Patent Application
20190330550
The present disclosure pertains to the field of energy utilization, and relates to a combustion method of fuels, a process and a procedure, in particular, a clean combustion method for a solid or semi-solid fuel, and more specifically, a clean combustion method for a fuel containing waste and scrap.
For a long time, people have burned biomass fuels such as trees, “fossil” fuels and artificial organic polymer waste materials for reasons such as waste disposal or acquisition of heat energy. However, along with the combustion, harmful smog may also be produced. That is. at the time of combustion, restricted by the combustion methods and the combustion devices, none of these materials is completely combusted.
Most of “fossil fuels”, taking bitumite as an example, are always scattered and burned, which seriously pollutes the atmosphere, and the heat-generating efficiency is low. The general heat-generating efficiency of large- and medium-sized stoves is only from 50% to 60%, and the minimum heat-generating efficiency of small-sized stoves is only from 20% to 30%. which not only causes waste of resources but also creates economic and environmental concerns.
With the development of technology, people also expect the born of a clean combustion (which may be defined as the one that the cleanliness of the exhaust gas is close to that emitted from the combustion of natural gas) technology of solid/semi-solid fuels with low reconstruction expenditure, low cost of use, and adaptability to various large-, medium-, small- and micro-sized stoves. Therefore, in the foreseeable future, coal and various combustible solids/semi-solids may still be used in parallel with various new energy resources for a long time. What's more, the use of a considerable portion of straw and inundant waste plastics and waste rubber tires as fuels is also a reasonable technical means to solve the environmental pollution.
Through years of efforts, the large-scale thermal power plant has now succeeded in spray-burning bituminous coal fines and has greatly improved the heat-generating efficiency to about 95%. After the exhaust gas is treated by a purification device, the purification rate reaches 90% to 95%, which is already close to clean combustion. However, there are still countless medium- and small-sized micro-enterprises which have low fuel availability and limited equipment, therefore, most of them cannot achieve the complete combustion of solid fuels such as pulverized coal, and are unable to install purification devices for exhaust gas. For example, when burning fuels formed from straw, there is still much smoke generated during the stages of ignition and fuel addition, meanwhile, with the use of air blast, most of the smoke dust is blown out. Therefore, there remains a need for a device which purifies the smog and smoke dust in the exhaust gas. Moreover, in such combustion manner, the calorific value is low. the fuels are not durable for combustion, and the cost is about more than 1 time of that of the scattered bitumite, so it is difficult to maintain this combustion manner for a long period of time.
In addition, compared with medium- and small-sized micro-enterprises, there are more difficulties in rural areas, especially villages and towns in outlying poverty-stricken areas, pastoral areas, areas along highways, field building and construction areas, and mining areas, where a large number of populations and houses are scattered. At the time of heating in living and production management and when there is no centralized heating in winter, the exhaust gas of the scattered bitumite is directly discharged, and the amount of the pollutants in the exhaust gas is 10 to 15 times of that generated by burning the same amount of bitumite in a large thermal power plant. The exhaust gas, smoke dust, and the like generated by such a combustion manner exacerbate the formation of haze, however, the engineering and technological field has had no good method to deal with it so far.
It is usually considered difficult to solve the problem of smoking when burning combustible solids, and it is necessary to first carefully analyze the cause of easy production of smoke. As is well-known, when combusted, wood such as biomass fuels, bitumite and lignite, and waste plastics and scrap rubber fire powder produce smoke all the time, regardless of whether stacked and then combusted or combusted in a stove.
The reason why the combustible solids are easy to produce smoke is explained by taking bitumite as an example. Bitumite either scattered and then combusted or briquetted and then combusted, is commonly ignited from the lower portion of a coal pile (briquette), and the protogenous high-temperature zone is right in the lower portion. When these fuels are heated to 200° C. to 250° C, a large amount of volatiles escapes sharply from the bitumite and is released into the atmosphere. Further, when the temperature is continuously raised to the ignition temperature of from 270° C. to 300° C., the escape of the volatiles of the bitumite is intensified, the thermal cracking of the volatiles produces a large amount of organics with large molecular weights, and the case of thermal disintegration of the coal briquettes into fine powder occurs sharply as well. In this temperature range, sulfur and organic and inorganic sulfur- and nitrogen-containing components are almost concurrently decomposed, oxidized, and escaped sharply (the pyrite in coal gangue starts to decompose into ½ equivalent of sulfur at about 200° C. according to the reaction formula FeS2=FeS+S in the presence of ultrafine activated carbon powder or reduced iron powder; at 300° C. to 400° C., almost all of the sulfur is rapidly decomposed and is all oxidized to sulfur oxide gas, which is greatly different from the ordinary pyrite that needs to undergo an oxidative desulfurization reaction at a high temperature of from 600° C. to 800° C.).
A more serious problem is that, during the combustion of a coal pile, these intensively escaped volatiles of bitumite, which consist of organics with large molecular weights, are mixed up with a large amount of original fine powder of the bitumite, fine powder and the powder of the fixed carbon newly generated from thermal disintegration (which are customarily called “smog” because they are visible to the naked eye and appear like mist; “zero smog” described in this specification means that there is no such smog visible to the naked eye when the exhaust gas is discharged front the chimney), and the exhaust gas of sulfur oxides and nitrogen oxides. These substances are surely cooled by the low-temperature coal layer above the combustion layer and the surrounding cold air, and are not easy to catch fire and even more difficult to be completely combusted since the internal space within the coal pile is narrow and the oxygen supply is inadequate (severely inadequate if without an air blast). Even if the combustion layer produces a flame, it is easily extinguished. An inevitable result is that when the entire coal pile is ignited from the bottom and the combustion continues until the temperature of the entire coal pile rises till the top appears red and hot, the exhaust gas in the above state will contain a distinctive suffocating odor of bitumite, appear as black brown thick smog, and emit in swarms. In addition, if the scattered bitumite is thrown onto the coal pile halfway and the coal pile is pried loosely for ventilation by a steel chisel, it is similar to a new round of ignition process at the bottom, flic same goes for the smoking status even if ignition is started from one side of the coal pile, or even from the top of the coal pile. Similar situation goes for the pollution discharge situation in the ignition-heating-combustion process of the solid fuels (such as lignite, plant fuels, waste plastics and scrap rubber tires) that are readily intensively thermally volatilized, thermally decomposed, and thermally disintegrated into organics with large molecular weights and charcoal panicles in a certain temperature range, and are cooled instantly due to inadequate and uneven supply of fuel gas.
In a word, conventional combustion allows the low-temperature zone in the upper portion and the high-temperature zone in the lower portion, meanwhile, the ventilation quantity is insufficient, the distribution is unbalanced, and the combustion is disorderly and incomplete. resulting in inevitable much black smoke in the exhaust gas and strong smell of sulfur. As for medium-, small- and micro-sized stoves, in particular, small-sized stoves which discharge the exhaust gas directly, it is necessary to completely change the way of combustion so as to eliminate the smog and the smell of sulfur.
In addition, in order to deal with the problem of the smog generated from combustion, people have also tried the igniting manner of “upper-ignition of honeycomb briquettes” for a period of time. However, all these technologies achieved from the research cannot reach the practical level and have entered the following misunderstandings.
1) The fire-leading coal placed on top in the stove may only be anthracite, which also results in that the actual combustion efficiency is not high, and there remains a need for taking advantage of special combustion means (as the key study objects are small-sized indoor stoves for residents and for greenhouses, the fire-leading coal placed on top of the coal pile in the stove may only be anthracites; in practice, bitumite, lignite, vegetable dyes, and the like must be blended in a large proportion to enable the content of the volatiles other than the fixed carbon to substantially raise to 30% to 40%, and even 50%, so that the long-flame combustion occurs front the very beginning and a high-temperature zone is rapidly formed in a large combustion chamber at the top of the coal pile).
2) An ignition agent used at the time of upper ignition is an oxidant. In general, these kinds of oxidants produce much smog upon ignition, which causes initial pollution instead. In addition, these kinds of oxidants are expensive and require special preservation, which not only increases the processing cost, but also imposes great pressure on production, logistics, storage, fire protection, and the like.
Cited Reference 1 (CN1959205A) discloses a combustion method of anthracite. A four-row burner consisting of primary air nozzles is arranged on the furnace wall near the center line o( the four walls at the lower hearth of the stove, and another four-row burner consisting of secondary air nozzles is arranged at the four comers of the hearth, and the secondary air nozzles are at the same level as the primary air nozzles. The primary and secondary air jet flows form two inner and outer concentric circles which are tangent to each other in rotary motions in the hearth, and the primary air is wrapped by the secondary air, a large amount of airflow in the primary air moves towards the central area of the hearth, and the secondary air forms an air curtain of an oxidizing atmosphere in the vicinity of the water wall. The nozzles of the tertiary air and the over fire air are arranged at the comers of the upper portion of the primary combustion zone to form a four-corner tangential jet flow.
Therefore, existing ways in this field of combusting and treating the solid or semi-solid fuels, especially these fuels containing waste and scrap, are still not desirable.
In view of the above-mentioned situation of the prior art, the technical problem to be solved by the present disclosure is to provide a combustion method for solid or semi-solid fuels, in particular, solid or semi-solid fuels containing waste and scrap. Users of this method may continue to use all sorts of medium-, small- and micro-sized stoves, and only after a slight reconstruction, the stoves may be piled up with columnar fuel briquettes with honeycomb-like vent holes which are prepared by formulating the excipients with various combustible solids and semi-solids, e.g., bitumite, lignite, plant fuels, waste plastics such as polyolefin, wastes from coal and petrochemical enterprises and so on, and molding. By means of “upper ignition-downward combustion”, a combustion which is static, orderly, long-flame, complete and zero-smog (throughout the whole combustion process from the moment of the ignition) is realized without an air blast or heightening the chimney, a high heat-generating efficiency and a high sulfur-fixing rate are achieved, and the cleanliness of the exhaust gas is close to that from natural gas and may be discharged directly without purification treatment (the exhaust gas of those formulated with rubber fire powder should not be discharged until being desulfurized and denitrated since the contents of sulfur and nitrogen are too high), that is, controlling the generation and emission of the toxic and harmful pollutants during a short combustion period.
Said method comprises:
in a hearth of a stove, placing at least a coal layer placed underneath, a fire-leading coal layer, and an ignition agent layer in this order in a direction from a lower portion to an upper portion;
igniting from the ignition agent layer to enable the combustion to start from the upper portion of the hearth;
wherein,
the hearth is constituted by a furnace core, and a fire-gathering plate is disposed at the top of the hearth;
the coal layer placed underneath and the fire-leading coal layer have a plurality of through vent holes: an cross-sectional area of the vent holes located in a center portion of the hearth is larger than the cross-sectional area of the vent holes located in a surrounding portion of the center of the hearth; and on each cross section of the coal layer placed underneath and the fire-leading coal layer, the cross-sectional area of the vent holes is 10% to 30% of the cross-sectional area of said cross section;
the stove is provided with an air inlet in the lower portion, and the area of the cross section of the air inlet is 105% or more and 120% or less of the cross-sectional area of the vent holes;
the stove also has an air hose for secondary air intake, an air inlet of the air hose is located in the lower portion of the stove, and a hose wall of the air hose is attached to an external wall of the furnace core of the hearth.
According to the method described above, the ignition agent layer and the fire-gathering plate at the top of the hearth form a combustion chamber, and the volume of the combustion chamber is greater than or equal to the volume occupied by the fire-leading coal layer.
According to the method described above, the ignition agent layer comprises a charcoal grille, and an ignition paste and/or an ignition cake, the ignition paste and/or the ignition cake contain(s) an alcohol having 2 to 9 carbon atoms, and the content of the alcohol is 45 mass % or more as per a total mass of the ignition paste or the ignition cake.
According to the method described above, the ignition agent layer is compounded by the charcoal grille and the ignition paste, and the charcoal grille is formed by a straw charcoal.
According to the method described above, the fire-leading coal of the fire-leading coal layer comprises a coke powder, bitumite, a dehydrated lignite, a hot-molten and extrusion-molded particle of waste polyolefin, a biomass fuel particle, and optionally rosin or industrial waste wax; the average particle diameters of the coke powder, bitumite, the dehydrated lignite, the hot-molten and extrusion-molded particle of waste polyolefin and the biomass fuel particle increase sequentially; and the fire-leading coal is treated with an alkaline substance.
According to the method described above, a total content of the volatiles in the fire-leading coal layer is from 30% to 45%, preferably from 40% to 45% of the total mass of the fire-leading coal layer.
With the adoption of the above-mentioned technical solution, the present disclosure achieves the following technical effects.
The present disclosure adopts the manner of upper-ignition, and by igniting the ignition agent layer having the above-mentioned composition, allows an orderly combustion of the ignition agent layer, the fire-leading coal layer and the coal layer placed underneath, such that a continuous and stable long-flame combustion may be formed quickly after ignition. Since the radiant heat and the conduction heat absorbed by the red hot coal layer on the surface of the fire-leading coal is greater than the convective heat carried away by the rising of the cold air, the long-flame combustion is able to move down at a fast speed. Due to the specific design of the composition of the fire-leading coal and the pattern of the vent holes therein, at any differential time interval, only the coal layer right adjacent to the lower end of the red hot coal layer reaches a secondary high temperature, gradually releases volatiles, and enters the red hot vent holes to start combustion, thus being capable of achieving an orderly and sequential combustion. Alter the fuel gas reaches the combustion chamber with a large space, the full combustion is basically completed. Finally, the fuel gas obtains a supplement of a secondary air intake at the main torch in the center of the fire-gathering plate and is burned off, thus achieving zero-smog combustion throughout the whole process. In addition, the combustion is performed orderly based on the same mechanism.
In some specific embodiments, the tiny coal particles in the fire-leading coal and a strong alkaline sulfur-fixing agent may be uniformly mixed and produce a combined action. In the process of combustion, the sulfur-fixing rate is quite high, and the heat-generating efficiency is also quite high, in terms of the nitrogen-fixing rate, although the process of neutralizing a nitrogen oxide with hydrated lime and potassium carbonate to form calcium nitrate and potassium nitrate is a reversible reaction within a high temperature range of 600° C. to 900° C. in the hearth, the reversibility is limited and the cleanliness of the exhaust gas is close to that from natural gas.
During combustion, in the numerous micropores inside the red hot coal layer, a considerable amount of the fixed carbon is gasified through a water coal gasification reaction with the intramolecular and extramolecular moisture of the coal pile under the catalysis of the nanoscale particles in the cheap pigment-grade ferric oxide added to the mixture, which greatly prolongs the long-flame combustion period. Therefore, it is possible to catalyze the combustion of coal without using the expensive ferrocene.
Since the ignition agent and the fire-leading coal in the present disclosure work in close coordination and have reached a remarkable ignition effect, formulas containing toxic and dangerous oxidants are absolutely abandoned, that is, nitrate, chlorate, perchlorate, manganate, permanganate, manganese dioxide, inorganic and organic peroxides, nitro-compounds, and nitrocellulose are not used. The present disclosure does not use substances containing a heavy metal element and other toxic and harmful substances either.
The combustion method provided in the present disclosure produces less slag after combustion, generally about 10%, and the structure of the slag is loose and may almost fall automatically, which is very essential to industrial stoves. The slag contains fertilizer elements such as potassium, calcium, magnesium, iron, silicon, sulfur and nitrate nitrogen, and is alkaline. After combined with the organic fertilizer, the slag is used as a fertilizer and acid clay improver.
Due to the binary design of the ignition cake/paste as a flammable product and the fire-leading coal as a combustible product, they are stored separately and thus the fire protection pressure is reduced.
A powerful smoke abatement mechanism allows a variety of low-quality waste solids containing dements of carbon and hydrogen (or carbon, hydrogen and oxygen) to be incorporated into the fuels of the present disclosure, as long as they do not contain lead, cadmium, arsenic, mercury, thallium, beryllium, halogen, and much nitrogen anti sulfur, and do not contain other toxic and harmful substances, and they are ideally consumed as clean fuels.
The combustion method of the present disclosure is particularly suitable for small-sized and some medium-sized stoves, and is able to replace the existing methods of bunting scattered bitumite, burning plant fuels, and incinerating scattered plastics such as waste polyolefin. The heat-generating efficiency and the cleanliness of the exhaust gas are close to those from natural gas, the investment in constructing a plant is not large, the cost of the raw materials is low, the reconstruction cost of the users' stoves is low, and the product is in terms of tonnage or calorific value per unit. All these are equivalent to the widely used anthracite briquettes. Therefore, it is possible to promote the combustion method according to the market model, reduce or even do not need financial subsidies, and speed up the resolution of these current outstanding environmental-energy issues.
Further, the technical solution of the present disclosure is not only able to increase the energy utilization rate but also reduce the environment pollution, while the combustion method of solids or semi-solids provided in the present disclosure is particularly suitable for the combustion operation of medium- and small-sized stoves. Meanwhile, in the fuels of the present disclosure, solid or semi-solid industrial wastes may serve as fuels, which increases the recovery rate of the waste energy and reduces the cost of combustion.
Additionally, even without adding an air blowing device additionally, the combustion method of solid or semi-solid fuels provided in the present disclosure is also able to achieve the above technical effects, which further reduces the simplicity and economy in the implementation of the combustion method of the present disclosure.
The present disclosure will be described in detail below. Unless otherwise stated, all of the units used in the present disclosure are international standard units, and the numerical values or numeral ranges should be understood as the numerical values or numerical ranges further including allowable errors in industry in addition to the numerical values themselves.
The “solid” described in the present disclosure refers to an object having the ability to maintain a certain shape at a normal temperature, that is, an object which is basically considered as having a stable outer shape.
The “semi-solid” described in the present disclosure refers to an object that is in the form of a paste or a slurry at a normal temperature, which is usually not considered as having a stable outer shape.
The “volatiles” described in the present disclosure refers to the liquid and gaseous products as follows. When a sample is heated in the absence of air under the specified conditions, the organic matter in the sample is heated and decomposed to a part of said liquid (in this case, it is in a vapor state) and gaseous products with small molecular weights, which are called volatiles. The fraction of the volatiles in the mass of the coal sample is referred to as the yield of volatiles or simply referred to as volatiles.
<Stove>
The combustion method of solids or semi-solids described in the present disclosure is carried out in a stove. The size of the stove per se is not particularly limited in the present disclosure. However, the inventors have found that the combustion method of the present disclosure is particularly suitable for the combustion in medium- and small-sized stoves.
A stove has a furnace body. The material of the furnace body is not particularly limited, and it may be the thermal insulation material or fire-resistant material commonly used in this field. Inside the furnace body, a furnace core is provided and a hearth is surrounded by the furnace core. The shape of the hearth is not particularly limited, but the hearth is preferably cylindrical in the preferred embodiments of the present disclosure from the perspectives of the preparation of the stove and the convenience of subsequent use.
As for the material of the furnace core, in some specific embodiments of the present disclosure, the furnace core is made from a material that has both thermal insulation property and fire resistant property, is alkaline on the whole, and has a high content of magnesium and a low content of transition element(s). Such material may be employed, especially for the furnace core around the combustion chamber formed by the ignition agent layer and the top of the hearth (or the fire-gathering plate) described below. This is because the furnace core usually endures long-time burning of the fuel in the stove and thus having a high requirement for the fire resistance, meanwhile, this is to prevent the flame from coming into contact with the furnace core and causing the furnace core to release toxic and harmful substances when the fuel in the stove is combusted. Therefore, the material of the furnace core used in the present disclosure has less or substantially no various transition metal elements.
In addition, if a material is selected only by considering the fire resistance, it will be very unfavorable for the smooth ignition of small-sized heating stoves in the zero-smog state in the freezing cold weather in winter and the early formation of the high-temperature zone in the large combustion chamber. Therefore, the thermal insulation property of the material is also of great significance.
In addition, the fuel (the fire-leading coal layer/the coal layer placed underneath) to be described below has an alkaline sulfur-fixing ingredient, and is thus strong alkaline and is liable to be welded to an acidic furnace core at a high temperature. The low content of the transition element(s) (coloring elements)) is also able to make the furnace core show a light color and good for light and heat reflection, which is also advantageous for rapid temperature rise after ignition.
The stove of the present disclosure has a fire-gathering plate at the top of the hearth. The material of the fire-gathering plate is not particularly limited, but in the preferred embodiments, the material of the fire-gathering plate is as same as that of the furnace core around the combustion chamber. Preferably, the color of the fire-gather plate is better close to white. In a further preferred embodiment, the periphery of the fire-gathering plate is embedded with stainless steel or cheap steel with sulfur resistance to reinforce it. In other embodiments of the present disclosure, the less heat the fire-gathering plate used absorbs, the more light and heat the arc-shaped surface thereof reflects downwards. Therefore, it is possible for the heat preservation of the combustion taken place in the combustion chamber, which is favorable for complete combustion in the combustion chamber and reducing the generation of harmful smog resulting from incomplete combustion.
Additionally, in some using occasions, for instance, as for those industrial and cooking stoves requiring great heat power and high operating temperature as well as stoves used for ignition in the freezing cold season, fast burning coal briquettes having a high calorific value are required to be used in combination with furnace core and fire-gathering plate with such high performance. In some other using occasions, for instance, those for heating, baking, drying, and boiling hot water in a region with lower latitude, low-cost coal briquettes may be selected to be used in combination with the furnace core and the fire-gathering plate.
In the present disclosure, the stove has an air inlet, also referred to as a primary air inlet at the bottom, which provides flowing air or oxygen for the combustion of the fuel in the hearth. In some specific embodiments of the present disclosure, a fire grate is provided at the primary air inlet, and the fire grate is a flat plate having grilles or a porous structure, which may provide supporting effect for the fuel in the hearth on the one hand, and may also provide air or oxygen entering the hearth or adjust the amount of air or oxygen entering the hearth on the other hand.
In some other specific embodiments of the present disclosure, in addition to the primary air inlet described above, the stove of the present disclosure also has a secondary air inlet, and the secondary air inlet introduces air or oxygen from the exterior of the stove into the interior of the hearth via a secondary air inlet hose. Typically, the air inlet of the secondary air inlet hose may be arranged beneath the exterior of the stove, while the secondary air inlet hose may be in connection with the combustion chamber inside the hearth from the top of the furnace core along the outer side of the furnace core inside the stove. Such a design enables the low-temperature gas entering from the air inlet of the secondary air inlet hose to be preheated by the furnace core when passing through the air inlet hose and coming into contact with the furnace core, which may improve fire adaptability to formulated fuels with a high content of volatiles.
In some specific embodiments, it can be observed that in the temperature-rising stage after ignition (igniting the ignition agent layer) in the hearth, a blue flame generated from the combustion enhanced by the airflow ejected via the secondary air inlet is able to intensively combust, which shows the synergistic effect of a secondary intake of air to the combustion.
Industrial stoves may be equipped with an automatic control device for air intake amount as required to ensure the flame coming out from the stove is in a state of oxidizing flame all the time, which is a very important control measure for complete combustion. Operators of simple stoves may also skillfully control the air intake amount to a preferable status based on experience.
What needs to be further explained is that at the end stage of each ignition and combustion, namely, after the end of the long-flame combustion, the secondary air inlet nozzle may be closed to avoid the secondary action of cooling.
Besides, in addition to the structure of the stove disclosed or defined above, it is self-evident that the stove used in the present disclosure may also comprise devices or structure conventionally applied in the stoves in this field, for example, may optionally comprise a heat insulating device of the stove, a processing device of stove ash, an additional air-blowing device, a monitoring device for the air intake amount of the secondary air inlet, a temperature detection and display device, and other auxiliary devices.
<Fuels>
The combustion method provided in the present disclosure is suitable for the combustion of the solid or semi-solid fuels.
In specific embodiments of the present disclosure, at least the coal layer placed underneath, the fire-leading coal layer and the ignition agent layer may be placed from the bottom to the upper portion of the hearth in this order.
In some specific embodiments, the fire-leading coal layer and the coal layer placed underneath may be formed by an independent combustion unit. In some other embodiments, the fire-leading coal layer and the coal layer placed underneath may be formed by arranging a plurality of independent combustion units in parallel
Ignition Agent Layer
In the combustion method of fuels provided in the present disclosure, upper-ignition method is adopted, that is, the ignition agent layer is ignited first.
The ignition agent layer of the present disclosure is as shown in
The ignition paste is more suitable for a case where many combustion units are combined, while the ignition cake is suitable for a case where I to 4 combination units are combined. However, the applications of the two are not thus limited, and they can be selected according to the situation of the actual stoves without any definite limitation on applications.
As for the ignition cake, the size thereof is not limited, and in some cases, it may adapt to the cross-sectional dimension of the hearth or may be ⅓ or more or ½ or more of the cross-sectional dimension. In addition, the thickness of the ignition cake is not limited cither. In general, when the thickness of the ignition cake is thin, the ignition cake is easily broken, especially for those having a large diameter, and it is thus slightly inconvenient. However, it may still be used after the fracture with little influence on the ignition effect.
As for the ignition paste, the control of the extrusion amount of a paste product should be noted, and it only needs to extrude the paste in an amount sufficient to ignite the fire above the fire-leading coal layer. The amount of the ignition paste is normally determined according to the actual situation.
In some specific embodiments of the present disclosure, a mixed low-carbon alcohol gel may be selected as the primary ingredient of the ignition paste and the ignition cake. Besides, the mixed low-carbon alcohol may form a sequential combustion so as to extend the combustion period of the ignition agent. More importantly, the gel comprised in the ignition paste or the ignition cake having the above composition is quickly melted by heat after ignition, and not only the fire-leading coal arranged at the bottom thereof has a large number of micropores, but also the surface of the solid particles comprised in the composition of the fire-leading coal may also have both hydrophilicity and lipophilicity, which is the same as or close to the surface characteristics of the selected alcohols. Therefore, the lower side of the ignited ignition cake is capable of quickly absorbing the burning gel liquid and a good situation of three-dimensional combustion and long-flame combustion appears soon, which is very favorable for forming the high-temperature zone in the large combustion chamber. This has been confirmed by the phenomena and the ignition effects observed by the inventors in numerous ignition tests and demonstrations.
The mixed low-carbon alcohol indicated in the present disclosure generally include alcohols having 2 to 9 carbon atoms, preferably alcohols having 3 to 7 carbon atoms, and they are not limited to the structural isomerism of the carbon chain and the number and isomerism of the alcoholic hydroxyl functional group(s). In addition, these low-carbon alcohols may be used in combination with aqueous solvents, for example, also including the case of using mere ethanol with or without water, and including the case of using mere isopropanol with or without water.
The alcohols which may be exemplified may be ethanol, ethylene glycol, propanol, isopropanol, propylene glycol, butanediol, isobutanol, neopentyl alcohol, isoamylol, pentanediol, hexanediol, etc. These alcohols may be one alcohol or a mixed alcohol of many kinds of alcohol.
Besides, though methanol has similar technical effects and has a low cost, however, due to its hypertoxicity, the present disclosure dose not advocate its wide use in small-sized stoves.
In addition, the composition of the ignition paste or the ignition cake may also comprise a solid ingredient and various additives. The solid ingredient may be selected from ingredient such as limestone, calcium carbonate, hydrated lime, etc. The additives may be selected from the metal salts of various fatty acids, such as the metal salts of oleic acid or stearic acid, and typically, calcium oleate, magnesium oleate, calcium stearate, magnesium stearate, and the like may be applied. These solid ingredients or additives may be used in a mixture of one or more substances.
In some specific embodiments of the present disclosure, as for the composition of fire ignition paste or the ignition cake, the content of the alcohols is 45% or more, preferably from 45% to 80%, e.g., 46%, 50%, 51%. 60%, 66%, 70%, etc., based on the total weight of the ignition paste or the ignition cake. In some other specific embodiments, the content of the solid ingredients) is 3% or less, for example. 2.5% to 0.5%. or the like.
The flash point, the ignition point, the melting point and volatility are mainly considered for the composition of the ignition paste or the ignition cake, and it is preferred that by adjusting the composition, the combustion of the ignition paste or the ignition cake has a gradient, so as to be capable of producing a sequential combustion in 2 to 3 minutes after ignition to extend the extremely valuable long-flame combustion period of the ignition agent.
At the time of preparing the ignition paste or the ignition cake, when the gel containing the mixed alcohol component and other components is produced, the difference between the lowest temperature to dissolve the gelatinizing agent safely and the temperature of paste formation and gelatinization should be greater than 20° C., preferably from 20° C. to 30° C. to facilitate the casting operation. The highest temperature during the casting operation is generally controlled at 60° C. to 70° C. to facilitate fire safety. When the air temperature is high and fluctuates greatly during the storage period of the ignition paste or the ignition cake, irreversible liquid alcohols are volatilized and precipitated from the gel. Therefore, in this case, the proportion of the volatile alcohols in the composition is as small as possible to reduce the harm to the human body or the environment. Meanwhile, the material cost may also be reduced.
As for the charcoal grille, in some specific embodiments of the present disclosure, the straw charcoal grille may be selected and used. As for the northern villages in winter, especially for scattered residents who use small-sized stoves for auxiliary ignition in remote and poor rural villages, the use of the charcoal grille is able to reduce ignition cost and improve ignition reliability
In some embodiments of the present disclosure, as for the ignition agent layer, a composite of the ignition cake and/or the ignition paste and the charcoal grille may be adopted. When the above composite is used as the ignition agent layer, the charcoal grille will soon be burned red after ignition and become a heat insulating layer of the fire-leading coal. When encountering the freezing cold weather, the charcoal grille is able to maintain the flame in the high-temperature zone in the upper portion of the fire-leading coal not excessively weakened to prolong the residence time of the long flame when the ignition cake is about to burn off, long flame is shortened and cooling and flameout may occur.
In some specific embodiments of the present disclosure, the ignition cake and the straw charcoal grille are combined into one, which is more convenient in use. As one of the serial ignition agents of the present disclosure, it has been successfully developed and is very easy to use. When producing this variety, a single-piece hot casting may be carried out. In region with slightly higher latitude, the ambient temperature is not high, the loss due to the volatilization of alcohols is small, the fire protection problem of the production plant is not great, and the production is convenient.
In addition, when producing the ignition cake, a long column-shaped ignition cake may be formed by casting and is simultaneously cut into several dozen pieces or more after cooling. The volatile loss of alcohols is small and the fire protection pressure is also small. In non-freezing weather, when a warm stove is ignited, as for the ignition of a combination of many combustion units, the straw charcoal grille may not be added, and it is possible to use a 3-5 mm ignition cake alone. The ignition cost is not high, and the ignition is also convenient.
When the composite of the charcoal grille and the ignition paste or the ignition cake is used as the ignition agent layer, after the ignition of the ignition agent layer, similar to the case described above, the upper and lower sides of the ignition cake or the ignition paste after being ignited are both capable of rapidly absorbing the ignited gel liquid, and a good situation of three-dimensional combustion and long-flame combustion appears soon, which is very favorable for forming the high-temperature zone in the large combustion chamber.
In the present disclosure, as for the ignition paste or the ignition cake, expensive raw materials, such as ethyl alcohol encapsulated with β-cyclodextrin, are not selected and used. The main consideration is that the ignition effect of the above-mentioned three-dimensional combustion is not good, and there is still an Obvious emission of the exhaust gas during use.
In brief, the ignition cake, the ignition paste and the charcoal grille in the ignition agent layer of the present disclosure may be flexibly used as appropriate.
Additionally, in the present disclosure, it is very important that the ignition agent layer and the fire-leading coal layer to be described below are of a binary design and are separately stored, which is advantageous for reducing the fire protection pressure. The commerciality-available fire-leading coal that may be ignited by a single match is a flammable product, which is very dangerous to be stored in large pile. The fire-leading coal of the present disclosure cannot be easily ignited by a single match or a lighter, and is only a combustible product. Although the ignition paste and cake are flammable products, the weight thereof is generally only 10% to 15% or less of the same fire-leading coal. They may be placed in a packing box or a case prior to use and are easy to be stored safely.
Fire-Leading Coal Layer
In the present disclosure, the fire-leading coal layer is arranged between the ignition agent layer and the coal placed underneath, and the heat released by the fire-leading coal layer is mainly utilized to form the high-temperature zone in the large combustion chamber at the top of the coal pile and ignite the coal placed underneath smoothly and steadily. For this reason, in the process of rapid combustion and temperature-rising, the fire-leading coal layer is required to certainly achieve an orderly, complete and long-flame combustion firstly and allow the red hot layer to move down according to the designed speed, thereby being capable of not producing black smoke and not discharging gas having foul smell and strong irritating smell of sulfur dioxide at the time of combustion.
To realize an orderly, complete and long-flame combustion, one or more of the following measures are taken in some specific embodiments of the present disclosure.
1) The ignition points of respective fud components in the composition of the fire-leading coal have a gradient from low to high, the above-mentioned fuel components are a biomass fuel, optional fallen rosin and industrial waste wax, an optional mixture of waste wax anti waste stearic acid prepared by the lost-wax casting method, hot-molten and extrusion-molded waste polyolefin particles, lignite, bitumite, and coke powder in turn.
2) The respective components have a proper particle size distribution according to the fineness, that is from thin to thickness: coke powder, bitumite, lignite, hot-molten and extrusion-molded waste polyolefin particles, and biomass fuel particles.
3) Each component itself has a rational particle size distribution either: for example, the coke powder all passes through a 60-mesh sieve, the bitumite all passes through a 30-mesh sieve, and the lignite all passes through a 20-mesh sieve. Of course, particle size distributions in nanoscale, micron-scale and millimeter-scale are also included. The hot-molten and extrusion-molded waste polyolefin particles are smaller than 2 mm, and a small amount of fine particles are allowed. The biomass fuel particles are smaller than 3 mm, and they carry a large amount of fine power themselves.
4) Lignite, fallen rosin, a mixture of waste wax and waste stearic acid prepared by the lost-wax casting method, other industrial waste wax, and the like are used in combination and then processed with an alkaline emulsion/solution, followed by adding biomass fuel particles and steaming and boiling the mixture. Macromolecular organic acids are mainly adsorbed by the biomass fuel particles and partially adsorbed by the pulverized coal so that they are highly dispersed, which facilitates the complete combustion of different components in a gradient. This effectively avoids the black smoke produced when a macromolecular organic containing a fused ring is burned, while substantially decreasing the production of 3,4-benzopyrene as a cancerogen. An alkaline sulfur-fixing ingredient is formed in the fire-leading coal after the alkaline treatment. Together with the emulsified rosin and the wax binders, most of the biomass fuel particles boiled in an alkaline emulsion or solution have become a self-produced cheap coal powder as organic binder, which is beneficial for reducing the ash content and increasing the calorific value of the formula. For instance, after partially emulsified with KOH, a lignite humic acid and a carboxylic acid with a large molecular weight in other raw materials, together with a plant fuel alkalized by KOH and Ca(OH)2, constitute a cheap organic binder to facilitate moderately reducing the ash content and increasing the calorific value and the mechanical strength. In the present disclosure, the alkaline emulsion or solution is prepared from an alkaline substance, which may be a hydroxide, an oxide or the like of an alkali metal, preferably NaOH, KOH, or Ca(OH)2.
5) The composition of the fire-leading coal is characterized by a high volatile content, which is beneficial for maintaining the long-flame combustion for most of the time. A total content of the volatiles is 40% to 45% based on the total weight of the fire-leading coal layer.
6) The plant fuel particles are combusted firstly and other volatiles and nanoscale carbon are combusted successively, such that there have been a considerable number of micropores as micro-coal gasification reaction chambers (selecting the pigment ferric oxide in which the nanoscale particles account for 10% or more as a catalyst to replace the expensive ferrocene) and combustion chambers of the fixed carbon in the red hot coal layer. A considerable portion of the fixed carbon is gasified, which facilitates prolonging the long-flame combustion period. The fuel gas keeps on burning when passing through the vent holes of the red hot coal layer which act as such small combustion chambers and gasification chambers, thereafter, the fuel gas is substantially combusted completely through the large combustion chamber, and finally undergoes after combustion in the main torch with a secondary air intake. The four-stage continuous combustion is another guarantee condition for realizing complete combustion.
7) The number of equivalents of hydrated lime compounding as a sulfur-fixing agent is 3 to 5 times that of the total sulfur content of the fuels, and potassium is added additionally to guarantee a high sulfur-fixing rate, since a portion of calcium will be consumed to bind to silicate instead of fixing sulfur.
8) The toxic and harmful raw materials in which the radioactive element(s) exceeds the standard and lead, cadmium, arsenic, mercury, beryllium, thallium, halogen or the like is contained are rejected, there is less slag in an amount of 10% to 12% in general, and the slag has a loose structure and may almost fall automatically. These factors are very important for a continuously-operating industrial stove. The slag contains fertilizer elements such as potassium, calcium, magnesium, iron, silicon and sulfur. The slag is slight alkaline after naturally absorbing oxygen and carbon dioxide for several days without being exposed to the rain, and it is suitable as a fertilizer and granular structure improver for acid clay after being used in combination with an organic fertilizer, or the slag may be used as a cement additive.
In the present disclosure, the combination of the ignition agent layer and the fire-leading coal is of importance. Such combination successfully realizes a combustion of a solid or semi-solid ignition agent which is oxidant-free, non-toxic and safe with no smog discharged during the overall combustion process (from the moment of ignition), to enable the combustion of the solid fuels to finally reach a cleanliness close to that of natural gas.
In addition, in the present disclosure, the fire-leading coal layer may be a monolayer fine-leading coal or may be designed as a multi-layer fire-leading coal.
Coal Layer Placed Underneath
In the present disclosure, the coal layer placed underneath is arranged below the fire-leading coal layer. The coal layer placed underneath is the primary coal layer which provides most of the calorific value, and the cost thereof may be lower than those of the igniting agent layer and the fire-leading coal layer.
In addition to the concerns that the compounding ingredient is capable of being smoothly ignited by the fire-leading coal and maintaining the long-flame combustion, the key point of the compounding ingredient is that it should be compounded with flexible raw materials which are low-cost/unit calorific value and may be purchased nearby; such as coke powder, lignite, biomass fuels, waste plastics, peats, and low-cost materials and wastes from coal and petrochemical industries, except for bitumite. In terms of the heating for enterprises such as chicken farms and the heating by cast-iron stoves for heatable brick beds, since the original hearth is large and many combustion units may be accommodated, the demand for calorific value is not necessarily high, but a low cost is desirable, and in this case, the compounding may be conducted in accordance with the following standard: (3800-4000)×4.1868 kJ/kg. If a strong heat power is demanded, the compounding may be conducted in accordance with the following standard: 5000×4.1868 kJ/kg or above.
In some specific embodiments of the present disclosure, the total volatile content in the formula of the coal layer placed underneath is suitably kept as at least 30% or more, e.g., from 40% to 50%. However, too high volatile content may cause the ash content of the fire-leading coal to be too low and the fire-leading coal is liable to collapse in the midway of combustion, thus blocking the vent holes in the upper portion. Containing a proper proportion of biomass fuel is favorable for ignition. Besides, the coal placed underneath undergoes great pressure when being molded, therefore, an inorganic binder may be added to the composition of the coal placed underneath alone and the drying is not required before release. When used, the coal placed underneath preferably maintains 10% to 15% moisture prior to the entry into a stove, which may increase the gasification rates of the fire-leading coal and its fixed carbon.
In addition, in the present disclosure, the coal layer placed underneath may be a monolayer coal placed underneath or may be designed as a multi-layer coal placed underneath.
Vent Holes of the Fire-leading Coal Layer and the Coal Layer Placed Underneath
In order to further enable the fuels in the fire-leading coal layer and the coal layer placed underneath to be completely combusted and to reduce the occurrence of smoke dust, in the present disclosure, the coal layer placed underneath and the fire-leading coal layer have a plurality of through vent holes from bottom to top, and the cross-sectional area of the vent holes located in the vicinity of the center portion of the hearth is greater than that of the vent holes located in the surrounding portion of the center of the hearth. Moreover, on each cross section of the coal layer placed underneath and the fire-leading coal layer, the cross-sectional area of the vent holes is 10% to 30%, preferably 15% to 25% of the urea of the above-mentioned cross section.
Such design may allow the coal placed underneath or the fire-leading coal located in the vicinity of the center of the hearth to be combusted completely, and fresh and Aiming air or oxygen may be provided via the air inlet and the air hose for secondary air inake arranged at the bottom of the stove.
When the fire-leading coal layer is combusted, the biomass fuel particles in the fire-leading coal layer are combusted firstly and other volatile* and nanoscale carbon are combusted successively, such that (here have been a considerable number of micropores as the micro-coal gasification reaction chambers and coal gas combustion chambers of the fixed carbon in the red hot coal layer, and the amount of gasification and combustion is increased, which facilitates prolonging the long-flame combustion period. The fuel gas keeps on burning when passing through the vent holes of the red hot coal layer which act as small combustion chambers, thereafter, the fuel gas is substantially combusted completely through the large combustion clumber in the upper portion, and finally undergoes after combustion in the main torch with a secondary air intake. The four-stage continuous combustion provides another guarantee for realizing complete combustion.
In addition, when a plurality of combustion units consisting of the fire-leading coal layer and the coal layer placed underneath are used in the hearth, these combustion units may be arranged in parallel and are ignited and combusted simultaneously. Under this circumstance, space may exist between different combustion units. In some specific embodiments, when a plurality of combustion units are used, the space between the combustion units located in the vicinity of the center of the hearth is larger than the space between the combustion units located in the periphery of the hearth, which is beneficial to the supply of air or oxygen to the fuels in the central portion so as to ensure that the fuels in different portions may be completely combusted.
In some other specific embodiments, the stacking manner of the fuels of the present disclosure is as below from top to down, combustion units which are placed in the hearth and to be combusted are as follows in turn: one straw charcoal grille and one ignition cake, one piece of fire-leading coal, and one to three pieces of coal placed underneath. If the ignition paste is used, after the coal placed underneath and the fire-leading coal are placed inside, the ignition paste is temporarily squeezed on the top of the fire-leading coal before ignition and then ignited immediately. If necessary, a plurality of composition units may be horizontally stacked arbitrarily for ignition, and this naturally needs to fit the hearth, the fire grate and the fire-gathering plate. When n plurality of composition units are employed in a large hearth, the using amount of the ignition agent is low, that is, the cost may be moderately lowered, the temperature rises quickly, and the beneficial effect is obvious.
Additionally, the cross-sectional area of the air inlet in the lower portion of the stove should be 5% to 20% larger than the total cross-sectional area of the vent holes in the above-mentioned fire-leading coal layer and the coal layer placed underneath, and the more the combined combustion units are, the closer the value is to 20%. The present disclosure is designed such that complete combustion can be guaranteed even without adding an air-blowing device individually and heightening the chimney.
Combustion Method
In the combustion method of solid or semi-solid fuels provided in the present disclosure, an ignition manner of upper-ignition is adopted, that is after each fuel layer are arranged in the hearth, the ignition agent layer on the uppermost layer is ignited, and a sequential combustion occurs in the hearth from top to bottom. Meanwhile, the combustion process is accomplished with the aid of an inlet air intake at the bottom and a secondary air intake.
1. Furnace wall
2. Furnace core
3. Heat insulating layer
4. Secondary air inlet hose
5. Primary air inlet and soot door
6. Fire-gathering plate
7. Large combustion chamber
8. Ignition cake
9. Coal placed underneath
10. Fire-loading coal
11. Straw charcoal grille
12. Outer ring vent hole
13. Inner ring vent hole
14. Cross channel for flame on straw charcoal grille
15. Cast-iron fire grate
(1) Technical problem to be solved by the present disclosure is as follows. Without fuels for compulsory heating, users may continue to use all sorts of medium-, small- and micro-sized stoves, and various combustible solids or semi-solids, e.g., bitumite, lignite, plant fuels, waste plastics such as polyolefin, wastes front coal and petrochemical enterprises and so on may be stacked inside only by slight reconstruction. The combustible solids or semi-solids are formulated with excipients elaborately and molded to columnar fuel briquettes with honeycomb-like vent holes. By means of “upper ignition-downward combustion”, a combustion which is static, orderly, long-flame, complete and zero-smog (throughout the whole combustion process from the moment of the ignition) is realized without an air blast or heightening the chimney, a high heat-generating efficiency and a high sulfur-fixing rate are achieved, and the cleanliness of the exhaust gas is close to that from natural gas and may be discharged directly without purification treatment (the exhaust gas of those formulated with rubber fire powder should not be discharged until being desulfurized and denitrated since the contents of sulfur and nitrogen are too high), that is, controlling the generation and emission of the toxic and harmful pollutants during a short combustion period.
(2) Solution to the technical problem of the present disclosure is as follows. The technical problem described in paragraph [001] is solved by integrating the following two well-known technologies and five innovative technical measures, which are described in detail in the following paragraphs [003] to [004], and paragraphs [005] to [0052], respectively.
Integrated well-known technology I: The combustion manner of “upper ignition-downward combustion” may form a coal briquette pile and a hearth temperature distribution in which the high-temperature zone is in the upper portion and the low-temperature zone is in the lower portion, so that the red hot coal layer instantly formed at the top of the fire-leading coal (10) is able to gradually move down at a designed speed since the radiant heat produced by the flame from the large combustion chamber (7) plus the conductive heat produced by the internal temperature difference within the coal body is higher than the convective heat taken away by the rising of cold air. In this way, at every differential time interval, only the secondary high temperature layer (or referred to as prospective red hot layer) right adjacent to the upper red hot coal layer generates a micro amount of thermal volatilization, thermal cracking, and thermal disintegration as well as the thermal decomposition and oxidation of compounds containing sulfur and nitrogen, which provides a significant condition for effectively avoiding the occurrence of the terrible situation where the manners such as downward ignition enable these combustible volatiles and pollutants containing sulfur and nitrogen elements to rush out so intensively that they have no time to be completely combusted and have no time to be absorbed by a Strong alkaline sulfur-fixing agent to transform into sulfate in solid form preserved in the coal briquette pile or slag, thereby inevitably producing black brown smog. Integrated well-known technology II: The matched stoves for briquette fuels must be provided with a secondary air inlet hose (4) and the space at the top of the coal pile must be covered with a fire-gathering plate (6) to form a simple combustion chamber. The secondary air inlet hose (4) is below the stove and the air inlet hose is adhered to the external wall of the furnace core (2), which is beneficial to the preheating of air and may improve the adaptability to the formula with a high content of volatiles. Blue flame generated by the combustion enhanced by the airflow ejected via the secondary air inlet (4) is often observed to be combusted brightly during the temperature-rising stage after ignition, which is sufficient to prove the effect.
People have usually ignited fuels such as wood and straw from the bottom since lime immemorial. In this way, the fire is heating up rapidly, but the smoke is heavy. People sometimes ignite the stacked solid fuels from the top and sides thereof, and the stacked solid fuels may be burned downward and inward slowly but producing less smoke, which is a familiar common sense of life that has been known to humans long before. The scientific principle thereof is that the radiant heat of the flame generated by combustion and the conductive heat generated by the heating of the fuels themselves may be equivalently spread in a 360-degree space without being affected by gravity. Therefore, the “upper ignition-downward combustion” mode has been a well-known technology since ancient times. The content described in paragraph [001] further explains that it is a well-known technology.
The innovative technical measures of the present disclosure are illustrated with 47 paragraphs, i.e., from paragraph [005] to paragraph [0052], and they are the vent holes and the more rational hole size and arrangement. Regardless of whether the coal briquettes are made into a cylindrical or square column and regardless of their geometric sizes, all of the coal briquettes adopt circular vent holes. The total cross-sectional area of the vent holes is 10% or more (depending on factors such as the product usage and the composition of the main raw material, the highest value may be up to 25% or the value is slightly higher and is up to 30%) larger than that of the commercially available anthracites (which are called honeycomb briquettes in the south), so as to adapt to the requirements for large oxygen consumption necessary for fast combustion of the volatiles with a high content in the fire-leading coal (10) of the present disclosure. Current cylindrical briquette having a diameter of 100 mm and having honeycomb-like vent holes is taken as an example. The diameters of several vent holes (13) in the central part of the briquette need to be extraordinarily enlarged so that they are 2 to 3 mm larger than those of the peripheral vent holes (12), to enable the big torch flame beam from the primary hole in the center of the fire-gathering plate (6) to further get fresh air in an amount similar to that obtained through the holes of the peripheral secondary air inlet hose (4) in the furnace core (2). When a plurality of composition units are horizontally stacked in a large hearth, the distance between the composition units in the central part is 2 to 3 mm larger than that between the peripheral units, which allows the central part of the coal briquette pile to get a secondary air intake amount similar to that of the peripheral part and provides another guarantee measure to enable the big torch fame from the primary* hole in the center of the above-mentioned fire-gathering plate (6) to get adequate amount of fresh air. The cross-sectional area of the air inlet (4) at the lower portion of the stove should be suitably 5% to 20% larger than the total cross-sectional area of the internal and external vent holes of the coal briquette pile, and the more the composition units are, the closer the value is to 20%. It is suitable that industrial stoves are equipped with automatic air volume control devices for the primary air inlet (5) and the secondary air inlet to ensure that the flame coming out of the stove is in the form of oxidizing flame all the time, which is a very important control measure for complete combustion. Operators of simple stoves may also skillfully control the air intake amount to a preferable status based on experience. At the end stage of each combustion, namely, at the end of the long-flame combustion, the secondary air inlet nozzle (4) may be closed to avoid the secondary action of cooling in the stove. Making the above four improvements which increase the oxygen supply is quite essential, in this way, complete combustion may be guaranteed without an air blast or heightening a chimney.
Large combustion chamber (7); There needs to be a space with sufficient size (whose volume is not less than that of one piece of coal placed underneath (9)) above the furnace core (2), and the furnace core (2) is covered with the fire-gathering plate (6) to form a simple large combustion chamber (7). In case that the formula has an extremely high volatile content and the coal gasification rate of the fixed carbon is also high, the height of the large combustion chamber (7) needs to be properly increased. The height of the combustion chamber plus the height of the furnace core (2) corresponding to Die height of the fire-leading coal (10) should be made from an material that has both a dominated thermal insulation property and a fire resistant property, is alkaline on the whole, and has a high content of magnesium and a low-content of transition element(s). This is because the material is selected only by considering the fire resistance as with the case of the conventional stoves, which is quite unfavorable for the crucial design of the smooth ignition in a zero-smog state in a small-sized heating stove in freezing cold weather in winter and the early formation of the high-temperature zone in the large combustion chamber (7). Coal briquettes formulated according to a sulfur-fixing formula are strong alkaline and are liable to be welded to an acidic furnace core at a high temperature. The low content of the transition element(s) (coloring element(s)) is able to make the furnace core light in color and good for light and heat reflection, which is advantageous for rapid temperature rise after ignition.
Fire-gathering plate (6): It is preferred that the fire-gathering plate (6) has a thin thickness and a light weight. Preferably, the material is the same as the thermal insulation-fire resistance material for the upper portion of the furnace core (2), and more preferably and most preferably, the color of the furnace core is nearly white. The periphery of the fire-gathering plate (6) is preferably embedded with a circle of stainless steel strip or cheap steel strip with good sulfur resistance to reinforce it. In short, the fire-gathering plate (6) is better, when it absorbs less heat and its inner arc-shaped surface reflects more light and heat downwards. As for industrial and cooking stoves requiring great heat power and high operating temperature, and stoves used for coal briquettes having the minimum diameter (often 100 mm), single composition unit and ignition in the freezing cold season, the fire-leading coal (10) having a high calorific value and capable of fast burning used in combination with the furnace core (2) and the fire-gathering plate (6) having such high performance is required. As for stoves for heating, baking, drying, and boiling hot water in a region with low latitude, low-cost fire-leading coal (10) may be chosen to be used in combination with the furnace core (2) and the fire-gathering plate (6).
Composition and structure of coal briquette pile: The stacking manner of the coal briquettes of the present disclosure is as below. From top to down, each combustion unit which is placed in the hearth and to be combusted comprises the following substances in turn: one straw charcoal grille (11) and one ignition cake (8), one piece of fire-leading coal (10), and one to three pieces of coal placed underneath (9). If the ignition paste is used, after the coal placed underneath (9) and the fire-leading coal (10) are placed inside, the ignition paste is temporarily squeezed on the top of the fire-leading coal (10) before ignition and then ignited immediately. If necessary, a plurality of composition units may be horizontally stacked arbitrarily for ignition, and this naturally needs to fit the hearth, the furnace core (2), the fire grate (15) and the fire-gathering plate (6). When a plurality of composition units are employed in a large hearth, since “many hands make light work”, the using amount of the ignition agent is less, i.e., the cost may be reduced appropriately, the temperature rises rapidly, and the beneficial effect is remarkable.
Ignition paste and ignition cake (8): A combination of the ignition paste and the ignition cake which is used in combination with the fire-leading coal (10) is able to form the high-temperature zone in the large combustion chamber (7) after ignition rapidly, which is the most important core technology of the present disclosure, wherein the unsafe and high-cost oxidant that discharges highly toxic smog firstly when ignited is replaced with a solid or semi-solid non-toxic ignition agent which is relatively safe. In addition, several improved technical measures including the stove, the furnace core, the fine-gathering plate, the secondary air supply, the cross-sectional area and arrangement of the vent holes of the coal briquettes, and ways of stacking and placing the coal briquettes finally succeed in realizing zero smog, low content of carbon monoxide, low content of volatile organic, low content of oxysulfide and low emission of smoke dust throughout the w hole combustion process from the moment of ignition, such that the combustible solids and semi-solids finally achieve a cleanliness of the exhaust gas close to that of natural gas. Besides, the slag is less in amount, loose and easy to fall, and is neither toxic nor harmful, which may be used as a fertilizer and granular structure improver for acid clay or a cement additive.
The ignition paste is more suitable for stoves with more composition units, and the ignition cake (8) is suitable for stoves with 1 to 4 combination units, but the ignition paste and the ignition cake have no clear technical specification of use and are selected by the consumers voluntarily. Thin ignition cakes break easily, especially for those with large diameters, and it is thus slightly inconvenient. However, it may still be used after the fracture and has little influence on the ignition effect. It should be noted that more extrusion amount of the paste product is not always belter, and the ignition cost may be saved after skillful at using it.
Selecting a mixed low-carbon alcohol gel as the ignition paste and ignition cake (8) to replace the expensive oxidant which emits toxic smoke when ignited enables the correct technical idea, namely, “upper ignition-downward combustion” of the briquette solid fuels, to possess all of novelty, advancement and utility, thus being able to be put into practice. Here, concerns are that the cost is slightly lower in comparison to using single ethanol and the mixed alcohol may form sequential combustion so as to extend the precious combustion time of the ignition agent. The third concern, which is also the biggest technical secret of the ignition agent, is as below. After being ignited, the gel melts rapidly due to heating; there are a large number of micropores in the fire-leading coal (10) on one hand, and the surface of the solid particles thereof is made to have both hydrophilicity and lipophilicity on the other hand, which is identical to the selected alcohols, and the case of the straw charcoal grille (11) placed above the ignition cake (8) is also similar. Therefore, for all these reasons, so the upper and lower sides of the ignited ignition cake (8) are capable of rapidly absorbing the burning gel liquid and a good situation of three-dimension combustion and long-flame combustion appears soon, which is very favorable for forming the high-temperature zone in the large combustion chamber (7). This has been repeatedly confirmed by the phenomena and the ignition effects observed by the inventors in numerous ignition tests and demonstrations.
The mixed low-carbon alcohols indicated in the present disclosure generally include alcohols having 2 to 9 carbon atoms, and are not limited to the structural isomerism of the carbon chain and the number and isomerism of the alcohol hydroxyl functional groups. Situations of using mere ethanol with or without water and using mere isopropanol with or without water are also included. Though methanol has similar technical effects and lower cost and may also be included, however, due to its hypertoxicity, the present disclosure does not advocate its wide use in small-sized stoves, and methanol is suitable for industrial stoves in facilities and plants with good management condition. The flash point, the ignition point, the melting point and volatility are mainly considered at the time of formulating, each of which should have a gradient in hope of being capable of producing a sequential combustion within 2 to 3 minutes after ignition to prolong the extremely precious long-flame combustion period of the ignition agent. When producing the gels, the difference between the lowest temperature to dissolve the gelatinizing agent safely and the temperature of paste formation and gelatinization should be greater than 20° C., preferably 30° C. to facilitate casting operation. The highest temperature is generally controlled at 60° C. to 70° C. to facilitate fire safety. When the air temperature is high and fluctuates greatly during the storage period of the ignition cake (8), a small amount of irreversible liquid alcohols are volatilized and precipitated from the gel, therefore, the ignition cake (8) should be stored in a warehouse which is dark, cool and ventilated. Material cost is low.
Straw charcoal grille (11): It is an attachment specially designed for assisting the ignition, reducing the ignition cost and improving the ignition reliability of small- and micro-sized stoves used in freezing cold weather in winter at high and middle latitudes and in regions with an elevation of 2000 meters or more. After the ignition, the straw charcoal grille (11) will burn itself red soon and become a heat insulating layer of the fire-leading coal (10). In the case of encountering freezing cold weather, the straw charcoal grille (11) keeps the flame in the high-temperature zone in the upper portion of the fire-leading coal (10) not excessively being shortened and the long flame will resurrect later when the ignition cake (8) is about to burn out the long flame is be shortened, cooling and flameout may happen, and a crisis appears. The flame contains a part of plasmas and carries more energy, which is very beneficial for generating strong radiation in the high-temperature zone of the hearth. Therefore, maintaining the long-flame combustion is an extremely important condition for the “upper ignition-downward combustion” state to be formed quickly and proceed continuously. The straw charcoal grille (11) may also be used in combination with an ignition paste.
The ignition cake (8) and the straw charcoal grille (11) are combined into one, which is more convenient to use. As one variety of the serial ignition agents of the present disclosure, it has been successfully developed and is very user-friendly. Please pay attention to later patent applications of the inventors and the applicant of the present disclosure. However, when the variety is produced, it may only be hot cast in a single piece. When the variety is produced in a region with slightly higher altitude in winter, the volatilization loss of alcohols is small and the fire safety issues in the workshop are not big either, therefore, it is convenient. Under other conditions, the investment in fire protection equipment and environmental protection equipment is slightly larger and the production is also feasible.
When the ignition cake (8) is produced, the raw material is first cast into a long column shape, and after cooling and demolding, each long cylindrical gel rod may be sliced at one time. The volatilization loss of alcohols is small, and the fire-protection pressure is also small. In non-freezing weather, in the case of igniting many composition units in a warm stove, the straw charcoal grille (11) may not be added and a 4 mm slice may be used alone. The ignition cost is not high and it is convenient.
Expensive alcohols encapsulated with β-cyclodextrin are not selected and used as the raw materials for the ignition agent. The main considerations are that the gel is capable of producing the ignition effect of the aforementioned three-dimensional combustion effect, and secondly, the cost of the gel is low.
In short, customers may flexibly use the three parts of the ignition agent, that is, the ignition cake (8), the ignition paste and the straw charcoal grille (11) as appropriate and at will.
The binary design of the ignition agent and the fire-leading coal (10) and the separate transportation and storage are advantageous for reducing fire-protection pressure, which is very important. Current commercially-available fire-leading coal (for use in igniting common anthracites from the bottom; it produces a large amount of black smoke upon ignition and must be ignited outdoors) which may be ignited by a single match is a flammable product, which is very dangerous to be stored in large pile. The fire-leading coal (10) of the present disclosure cannot be easily ignited by a single match or a lighter, and is only a combustible product. Although the ignition paste and the ignition cake are flammable products, the volume and weight thereof are generally only 10% to 15% or less of those of the fire-leading coal (10). They are placed in a packing box or case, and are easy to be transported and stored safely. In addition, the fire-leading coal (10) needs to be dried by heating, while the ignition agent is neither necessary nor allowed to be dried by healing.
As for the formulas, production processes and packing methods of the ignition paste, the ignition cake (8) and the upper-mounted straw charcoal grille (11) placed above, please refer to the specific embodiments (1), (2) and (3) in Part V.
f. Fire-leading coal (10): It is an important structural-type coal block necessary for connecting the ignition paste/cake (8) with the coal placed underneath (9), anti the heat released from the fire-leading coal is mainly relied on to form the high-temperature zone in the large combustion chamber (7) at the top of the coal briquette pile and smoothly and steadily ignite the coal placed underneath (9). Therefore, the fire-leading coal is required to certainly reach an orderly, complete and long-flame combustion firstly in the process of rapid combustion and temperature rising, so as to allow the red hot coal layer to gradually move down at a designed speed, thereby not producing black smoke and rarely emitting gas containing suffocating foul smell and strong irritating smell of sulfur dioxide which are produced when bitumite is combusted in conventional ways during the whole combustion process of the coal briquettes.
In order to realize an orderly, complete and long-flame combustion, in the present disclosure, the technical principle and technical measures employed in preparing the fire-leading coal (10) and the coal placed underneath (9) are as follows.
1. The ignition points of respective fuel components have a proper gradient from low to high, the above-mentioned fuel components are a plant fuel, fallen rosin, industrial waste wax, lost-wax casted waste wax (containing stearic acid), waste polyolefin plastics, lignite, bitumite, coal slime, . . . coke powder in turn.
2. The respective fuel components must have a proper panicle size distribution according to fineness.
3. Each component itself has a rational particle size distribution. For instance, bitumite ail passes through a 30-mesh sieve, and particle size distributions in nanoscale, micron-scale and millimeter-scale arc naturally included; lignite all passes through a 20-mesh sieve, and its particle size distribution is similar to that of bitumite; the sheet of waste polyolefin plastics has a particle size of less than 2 mm and contains a few fine particles; the plant fuel particles have a particle size of less than 3 mm, and they carry a large number of fine power themselves.
4. Lignite, fallen rosin, lost-wax casted waste wax, and other industrial waste waxes are reasonably formulated and used. After using a KOH solution to neutralize a part of the macromolecular organic acids to form an emulsion, the plant fuel particles are then added to be properly boiled. The macromolecular organic acids are mainly adsorbed by the plant fuel particles and partially adsorbed by the fine pulverized coal so that they are highly dispersed, which facilitates an orderly combustion and thus effectively avoiding the black smoke produced when a macromolecular organic containing a fused ring is burned, while substantially decreasing the production of 3,4-benzopyrene as a cancerogen. Additionally, the plant fuel particles boiled in a KOH alkaline solution, together with the emulsified rosin, waxes and a lignite binder, become a cheap organic binder of pulverized coal and other excipient powder that is self-produced by the way in the production process, which is beneficial for reducing the ash content, increasing the calorific value of the formula and maintaining the mechanical strength of the coal briquettes.
5. In addition to the occurrence stales of the raw materials described in paragraphs [0022], [0023], [0024] and [0025], the formula of the fire-leading coal (10) must be featured in a high volatile content, which is a technical measure necessary for keeping long-flame combustion for most of the time. In the instant specification, the volatile content of bitumite and lignite plus the total weight of the macromolecular organics contained in the plant fuels and the like are counted into the total volatile content. According to different uses of the product, the total volatile content thereof is suitably maintained as at least 30% or more, generally 40%, and 50% if particularly required. However, too high volatile content may cause the ash content to be excessively low, and the fire-leading coal is liable to collapse in the midway of combustion, thus blocking the vent holes. In addition, it is favorable for the coal placed underneath (9) to be smoothly ignited when it contains a moderate proportion of the plant fuels.
6. The plant fuel particles are combusted firstly and other volatiles and nanoscale carbon are combusted successively, such that there have been a considerable number of micropores as micro-coal gasification reaction chambers of the fixed carbon and coal gas combustion chambers in the red hot coal layer, and the amount of gasification and combustion is increased, which facilitates prolonging the long-flame combustion period. The fuel gas keeps burning when passing through the vent holes (12, 13) of the red hot coal layer which act as small combustion chambers, thereafter, the fuel gas is substantially combusted completely through the large combustion chamber (7), and finally undergoes after combustion in the main torch with a secondary and a third air intake. The four-stage continuous combustion is another guarantee condition for realizing complete combustion.
A cylindrical fire-leading coal (10) having a diameter of 100 mm is taken as an example. Ingredient: dry base: 200 g for each; and a heat of (5000-5300)×4.1868 kJ/kg is suitable; the fire-leading coal is divided into upper and lower layers and it is suitable for the fire-leading coal to be fed twice and hydroformed once. As for the formula, the production process and the packing method of a product for heating, please refer to the specific embodiment (4) in Part V.
f. Coal placed underneath (9): It is the main coal briquette which provides most of the calorific value, and the cost is lower than those of the ignition agent and the fire-leading coal (10). In addition to the concerns that the compounding ingredient is capable of being smoothly ignited by the fire-leading coal (10) and maintaining the long-flame combustion, the key point of the compounding ingredient that it should be compounded with flexible raw materials which are low-cost/unit calorific value and may purchased nearby, such as coke powders, lignite, plant fuels, waste plastics, peals as well as low-cost materials and wastes from coal and petrochemical industries, except for bitumite. In terms of stoves used for warming, heating, boiling water and baking for industrial enterprises such as livestock farms and scattered residents, since the original hearth for burning scattered bitumite and plant fuels is large and many composition units may be accommodated, the demand for the calorific value is not necessarily high, but a low cost is desirable; and in this case, the formula may be designed in accordance with the following standard: (3800-4000)×4.1868 kJ/kg. If a strong heat power is demanded, the formula may be designed as 5000*4.1868 kJ/kg or more.
The molding pressure of the coal placed underneath (9) is large, and an inorganic binder may be added alone without drying before release. The coal briquettes preferably maintain 10% to 15% moisture prior to the entry into stoves, which may increase the gasification rates of of the fixed carbon. As for the formula and the production process, please refer to the specific embodiment (5) in Part V.
The mixed low-carbon alcohol ignition agent, the elaborate formula and production process of the coal briquettes in combination with the novel stove, furnace core and fire-gathering plate and a secondary or even a third air inlet structure as well as the combustion manner wherein the high-temperature zone is in the upper portion and the low-temperature zone is in the lower portion which is formed by “upper ignition-downward combustion” together constitute the sufficient and necessary conditions of an orderly, long-flame and complete combustion, and finally realize the effects of zero-smog emission in the whole combustion process and a high sulfur-fixing rate.
(3) The beneficial effects of the present disclosure w ill be further described in detail as follows: {circumflex over (1)} Since a zero-smog, orderly and long-flame combustion starts from the moment of ignition at the top of the vertical composition units of a mixed low-carbon alcohol gel ignition agent, the fire-leading coal (10) and the coal placed underneath (9) which are placed in the furnace core of a specialized stove, so the high-temperature zone is firstly formed in the large combustion chamber (7) at the top of the coal briquette pile. Since continuous and stable long-flame combustion may be formed soon after the ignition, the radiant heat and the conductive heat absorbed by the red hot coal layer on the surface of the fire-leading coal (10) is greater than the convective heat taken away by the rising of cold air and thus the red hot coal layer is allowed to move down rapidly. Due to the elaborate design of the ingredients in the formula and the occurrence state of the fire-leading coal (10), at any differential time interval, only the coal layer right adjacent to the lower end of the red hot coal layer reaches the secondary high temperature and differentially releases volatiles and generates flammable products from thermal decomposition, thermal cracking and thermal disintegration, all of which gradually enter the micropores in the red hot coal layer for preliminary combustion, and then enter into the red hot vent holes to be combusted continuously. The fuel gas is substantially combusted completely after reaching the large combustion chamber (7), and finally bunt out with the aid of the supplementary air intake brought by the inner ring vent hole (13) in the primary torch in the center of the fire-gathering plate (6), that is, an orderly sequential combustion is realized reliably and the bad state in which the exhaust gas unable to be completely combusted in a scattered state is discharged intensively is completely eradicated, so it appears as zero-smog combustion in the whole process and the heat-generating efficiency is certainly very high. Moreover, fortunately, based on the same mechanism of orderly combustion, the coal-based sulfur in the coal is orderly oxidized after being heated and becomes SO2 and SO3, and undergoes acid-base neutralization reaction to become the sulfates and sulfites of potassium/calcium/magnesium/iron while most of the sulfates and sulfites are fixed in the slag, so the sulfur-fixing rate is also quite high during the combustion process. Only the nitrogen-fixing rate is limited since neutralizing nitric oxide with hydrated lime and potassium carbonate to form calcium nitrate and potassium nitrate is a reversible reaction within a high temperature range of 600° C. to 900° C. in the hearth, but the cleanliness of the exhaust gas is already close to that of the exhaust gas emitted from the combustion of natural gas.
{circumflex over (2)} In the numerous micropores inside the red hot coal layer, a considerable amount of the fixed carbon is gasified through a water-gas shift reaction with the intramolecular and extramolecular moisture in the coal briquettes under the catalysis of the cheap nanoscale iron sesquioxide particles added to the mixture, which greatly increases the long-flame combustion period. Hence, expensive ferrocene may not be used to catalyze the combustion of fuels such as bitumite.
{circumflex over (3)} Since the ignition agent and the fire-leading coal (10) of the present disclosure work in close coordination and have achieved a remarkable ignition effect, formulas comprising toxic and dangerous oxidants are absolutely abandoned, namely, not using nitrate. chlorate, perchlorate, manganate, permanganate, manganese dioxide, inorganic-organic peroxides, nitro-compounds, nitrocellulose, etc. The formula of the present disclosure also strictly rejects the use of a raw material containing heavy metal element(s) such as lead, cadmium, arsenic, mercury, and thallium and a raw material in which the radioactivity is out of standard, and strictly rejects the use of the toxic and harmful raw materials containing bismuth, halogen, or the like.
{circumflex over (4)} There is less slag in an amount of 10% to 12% in general, and the slag has a loose structure and may almost fall automatically, which is very important for a continuously-operating industrial stove. The slag contains fertilizer elements such as potassium, calcium, magnesium, iron, silicon and sulfur. The slag is slightly alkaline after naturally absorbing oxygen for several days without being exposed to the rain, and it is suitable as a fertilizer and granular structure improver for acid clay after being used in combination with an organic fertilizer.
{circumflex over (5)} Due to the binary design of the flammable ignition cake (8) and the combustible fire-leading coal (10), they are transported and stored separately and thus reducing the fire-protection pressure. The five-leading coal (10) cannot be easily ignited directly by a single match or a lighter.
{circumflex over (6)} The powerful smoke abatement mechanism allows a variety of tow-value waste solids or semi-solids containing elements of carbon and hydrogen (or oxygen) to be incorporated into the formula of the present disclosure, as long as they are free from the aforementioned toxic and harmful substances, and they are ideally consumed as clean fuels. Scrap rubber fire powder having higher sulfur and nitrogen content may be blended in the coal placed underneath (9) in a larger proportion to reduce the product costs, but the exhaust gas cannot be directly discharged and should be discharged after purified by desulfurization and denitration device, thus being suitable for use in industrial stoves.
{circumflex over (7)} The product of the technology of the present disclosure is mainly used for small- and micro-sized stoves and some medium-sized stoves where compulsory combustion is not required, and is able to replace the combustion of scattered bitumite, the combustion of plant fuels, and the incineration of waste plastics such as polyolefin. The heat-generating efficiency and the cleanliness of the exhaust gas are already close to those from the combustion of natural gas, the investment in constructing a plant is not large, the cost of the raw materials is low, the reconstruction cost of the users' stoves is low, and the product is in terms of tonnage or calorific value per unit. All these are equivalent to or slightly lower than the widely used anthracite briquettes. Therefore, it is possible to promote the product according to the market model and reduce or even do not need to use financial subsidies.
Names of the reference signs in
1. Furnace wall 2. furnace core 3. Heat insulating layer 4. Secondary air inlet hose 5. Primary air inlet and soot door 6. Fire-gathering plate 7. Large combustion chamber 8. Ignition cake 9. Coal placed underneath 10. Fire-leading coal 11. Straw charcoal grille 12. Outer ring vent hole 13. Inner ring vent hole 14. cross channel for flame on straw charcoal grille 15. Cast-iron lire grate
(1) Ignition paste The formula is as follows: a) isopropanol: 46%. b) ethanol: 20%. c) ethanediol: 5%. d) calcium oleate: 3%, e) magnesium oleate: 1%, f) calcium stearate: 3%, g) magnesium stearate: 1%. and h) water: 21%.
In a 0.5 m3 enamel-jacketed anchor stirring reactor, a, b and c are added. The stirrer is turned on at a low speed. The jacket steam is opened and heated slowly up to 60° C., while the gel paste-forming agents d, e, f and g are added gradually in batches, and finally, a burning rate inhibitor and gelling temperature rate regulator h is added slowly. A samples is taken and tested. The sample is qualified if the paste-forming point is 46±2° C. The sample is kept at 55° C. to 60° C. and injected into a 200 to 500 g polyvinyl chloride collapsible tube, which is sealed with a screw top, naturally cooled to the normal temperature, and thereafter packaged by a 10 kg corrugated carton for storage in the warehouse.
Since this ignition paste is a flammable product, aspects such as the layout and the construction of the workshops, test rooms and warehouses, the installation of workshop equipment and various lines, personnel training are all strictly implemented according to the fire protection regulations. The same is true with the ignition cake (8) below.
(2) Ignition cake (8): The formula is as follows: a) isopropanol: 46%, b) ethanol: 20%, c) ethanediol: 5%, d) water: 20%, e) calcium stearate: 5%, f) magnesium stearate: 3%, and g) hydrated lime: 1%.
In the same equipment for producing the ignition paste, a, b and c are added. The stirrer is turned to the lowest gear. The jacket steam is opened and heated up slowly, while the gelatinizing agent is added in batches. When the temperature of the material in the reactor rises to 60° C., the steam is turned down. After the feed liquid is almost transparent, a burning rate inhibitor and gelling temperature rate regulator d is added slowly, a supplementary curing agent g is sprinkled finally, and the temperature is allowed to rise to 70° C. A samples is taken and the gelatinization temperature is measured, which should be higher than 40° C. The temperature of the material is maintained at 50° C. to 60° C., and then the feed liquid is started to be poured into a stainless steel die having a diameter of 100 mm and a height of 150 mm. The layout and the size of the core rod of the die are prepared as specified in in
(3) Straw charcoal grille (11): To a blender mixer, added are 100 kg of fully carbonized product of straw, pine, China fir, or hemp pole that all pass through a 10-mesh sieve, 2.8 mole or more of potassium water glass with a concentration of 15% to 20% in an amount of 6% of the carbonized product based on the dry base, and 3 kg of hydrated lime powder. After uniformly blended, the mixture is transferred to the hopper of the molding press and molded into the straw charcoal grille (11) as shown in
(4) Fire-leading coal (10): The above-mentioned recommended fire-leading coal (10) which has a diameter of 100 mm, is 200 g on dry base and has a calorific value of (5000-5300)×4.1868 kJ/kg is taken as an example, and the formula and the production process of the double-layer material thereof are as below:
a) Pine sawdust: 20 kg (15 kg); b) peanut shell powder: 5 kg (9 kg); c) fallen rosin: 9 kg (4.5 kg); d) lost-wax casted waste wax: 9 kg (4.5 kg); c) potassium hydroxide: 3.2 kg (1.6 kg); f) bitumite: 6000×4.1868 kJ/kg, volatiles: 35%, 18 kg of bitumite which all passes through a 60-mesh sieve. 30 kg of bitumite which all passes through a 25-mesh sieve (grade identical with the former one, 65.85 kg of bitumite which all passes through a 25-mesh sieve); g) hydrated lime powder 3.5 kg (5 kg); h) 40% potassium water glass: 5 kg (8 kg); i) water: 40 kg (35 kg); j) ferric oxide pigment: 0.3 kg (0.35 kg). The data in the parentheses are the formula data of the lower-layer materials of the fire-loading coal (10).
An open iron pan with a paddle stirrer was placed over a small-sized demonstration stove for boiling water in enterprises that use a combination of nine coal piles with a diameter of 100 mm formal by the product of the present disclosure, i is added, the coal pile is ignited to heat up, the stirring is started at the lowest speed, e and c are added, other debris such as branches, leaves, stones in c are picked out by hand, and d is added. When the temperature in the pan is close to the boiling point, the dissolution and emulsification operations should have been completed. The valve of the discharge pipe equipped with a wire mesh for filtration at the side pipe orifice at the bottom of the pan is switched on. The emulsion is filtered while it is hot and is allowed to flow into a kneading pot with a steam heating jacket, and a and b have already been added in the pot. After the completion of feeding, the kneading is started and the steam is opened until a and b are completely wet, the kneading is stopped, and the mixture is insulated for 15 to 20 minutes. f, g, h and j that have already been mixed uniformly in a dry mixer in advance are added and kneaded for 15 to 20 minutes until the materials are completely and uniformly mixed. The kneaded stock is conveyed to the 1# hopper of a hydraulic molding machine, and this is the upper feedstock of the fire-leading coal (10). Another set of the same system is used to prepare the lower feedstock of the fire-leading coal (10), which is conveyed to the 2# hopper of the hydraulic molding machine. The hydraulic molding machine is started and 1# feedstock and 2# feedstock in equivalent amount are conveyed into a molding cylinder in turn while they are hot, compression molded at one time, and transferred to a big large-scale low-temperature ventilation drying room while they are hot. The fire-leading coal (10) is dried at 60° C. until the moisture content is less than 10%, and is moved out together with a rail car to the natural cooling section in the workshop. When the temperature is lowered to 35° C. or less, each fire-leading coal (10) is packaged in an ultra-thin polyethylene plastic bag and then placed in a corrugated carton for storage. The molding pressure is carefully adjusted according to the variety and specification of the product to maintain a proper crispness, which facilitates a rapid temperature rise and the coal gasification reaction of the fixed carbon in the ignition stage. It is not suitable to blindly pursue high mechanical strength. The aforementioned formula has already had sufficient adhesive strength, and the molding pressure may be well adjusted such that the mechanical strength of the product is able to adapt to the logistic operation in a non-barbaric state,
(5) Coal placed underneath (9): The high-temperature zone above the coal placed underneath (9) has been already formed, and is easy to be smoothly ignited. The flexibility of the formula is large, but it is still necessary to pay attention to the reasonable occurrence stale and the gradient particle size distribution of the components thereof, so that the long-flame combustion period is prolonged as much as possible. The focus of some formulas has turned to the use of the low-cost raw materials and the product is supplied to the scattered residents in villages for heating at a lower unit price. The formula and the key points of the production process of a product for heating are as follows: a) straw pieces: 10%. b) pine sawdust: 10%, c) 20% of potassium water glass: 8%, d) bitumite powder (5000*4.1868 KJ kg, volatiles: 30%. sulfur: 2.5% or less): 68%, e. hydrated lime powder (in term of equivalent): equivalent to 3 times of sulfur equivalent, f) ferric oxide pigment: 0.5%, g) plastic pieces of polyolefin waste: 5%, and h) water: 5%.
d with a fineness of 25 mesh and the moderately-sized a, b and g are weighed, put into a mixer, and mixed for about 10 minutes. Thereafter, the pre-mixed e and f that are 10 times of the weight of d, a and h are added and the mixture is mixed continuously for several minutes, c is sprayed, and the mixture is mixed for several minutes. The mixture is moved into the hopper of the hydraulic molding machine, molded with a larger pressure, stored and dried naturally. When entering the stove, containing 10% to 15% of moisture is quite advantageous to the coal gasification reaction of the fixed carbon.
The formulas and production processes exemplified in the specific embodiments are merely for further illustrating the content of the present disclosure, but are not limited thereto, and the embodiments are all included in the scope of the present disclosure as long as they adopt the following technical contents in the briquette fuels for “upper ignition-downward combustion”: 1. the gel paste or cake (8) of low-carbon alcohols is used as the ignition agent, and the straw charcoal and other plant charcoals are used as auxiliary ignition agents, regardless of how the formula, the production process and the packaging form are adjusted; 2. the formula and the molding process of the fire-leading coal (10), as long as a) an ingredient having a high volatile content of 30%-40%-50% is adopted, b) both of the ignition point and the particle size of each fuel component are arranged in gradient to facilitate an orderly and sequential combustion, and c) after lignite aid other materials containing a macromolecular organic acid are partially emulsified (neutralization reaction with potassium hydroxide and the like), the mixture and a plant fuel boiled with an alkaline substance such as potassium hydroxide, hydrated lime and plant ash together constitute a fool and binder, so as to save the cost of the binder, regardless of how the formula, the production process and the packaging form are adjusted; 3, commercial iron sesquioxide containing at least 10% or more of iron sesquioxide and having a particle size of 50 nm or less is adopted to catalyze a part of the fixed carbon in the coal components to be gasified in the micropores and the vent holes in the red hot coal layer before combustion, so as to facilitate the extension of the long-flame combustion period; 4. the furnace core (2) has a height of at least from the bottom of the fire-leading coal (10) to the bottom of the fire-gathering plate (6), and the fire-gathering plate (6) itself is made from a light alkaline fire-resistant material having good thermal insulation property and containing a high content of magnesium and a low content of transition elements); 5. a total area of the air inlet of the stove and the vent holes of the coal briquettes is enlarged by 10%-20%-30%, as compared to that of anthracites originally used, and the diameter of the inner ring vent hole (13) is larger than that of the outer ring vent hole (12); 6. after tests, the raw material does not contain radioactive elements beyond standard, does not contain lead, cadmium, arsenic, mercury, thallium, and beryllium, and does not contain halogen, much sulfur and nitrogen as well as other toxic and harmful substances, so the burnt slag mainly contains elements such as potassium, calcium, magnesium, iron, silicon and sulfur, thus being used as a fertilizer; 7. various combustible solids and semi-solids, including the low-value wastes thereof, may all be used as a formulated fuel according to the methods described in the present specification to realize highly efficient and clean combustion, and are thus included in the content of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810390637.4 | Apr 2018 | CN | national |
