The present application is a U.S. national stage entry of International Application No. PCT/CN2020/070739, filed Jan. 7, 2020, which claims the priority to Patent Application CN 201920025966.9 entitled “SMALL STOVE, STOVE CORE AND SHAPE OF SAME ASSORTED WITH SMOKELESS COMBUSTION OF COMBUSTIBLE SOLIDS/SEMISOLIDS”, filed on Jan. 8, 2019, to China National Intellectual Property Administration, and Patent Application CN 201910014780.8 entitled “SMALL STOVE, STOVE CORE AND SHAPE OF SAME ASSORTED WITH SMOKELESS COMBUSTION OF COMBUSTIBLE SOLIDS/SEMISOLIDS”, filed on Jan. 8, 2019, to China National Intellectual Property Administration, which are incorporated herein by reference in their entirety.
The present invention relates to the efficient and clean combustion control technology for combustible solids and semisolids, and in particular, to technologies for a stove which is suitable for the field of non-forced combustion and assorted with smokeless, efficient and clean combustion of a shaped fuel block (hereinafter referred to as briquette) containing bituminous coal, other combustible solids/semisolids and auxiliary materials, and is usually (but not always) small and medium in size, and its stove core and a shape of briquette.
The present application exemplifies a cylindrical briquette with a diameter of 100 mm and assorted stove, stove core and flame concentrator for illustrative purpose, and includes, but is not limited to, stoves for non-forced combustion purpose of various shapes, structures, sizes and uses, and assorted stove cores and briquettes that can be conveniently manufactured as needed according to the techniques of the present invention. Among these, the stove core and the flame concentrator are either suitable for high-volume production in modules, or conveniently and quickly used to modify a stove by cutting and combining prefabricated standard modules on site in a building block manner.
Percentages relating to weight in the application refer to the parts by mass.
The term “volatile component” has the same meaning as the parent patent (Application No. 201810390637.4), i.e., including volatile matters in coal and other organic matters in the composition containing carbon, hydrogen, oxygen, sulfur, nitrogen and other elements which may evaporate to produce fuel gases at 300° C. or below.
The present invention relates to details of the techniques for thermally insulating/refractory stove core assorted with a small stove as shown in
It is known from the parent patent (Application No. 201810390637.4) and the Specification and
In the briquette stack of beehive vent holes established by the parent patent (Application No. 201810390637.4), in order to maintain a long-term combustion, 2-3 underlying briquettes (9) with a dry weight of 500 g and a height of 90 mm are stacked. This brings difficulties in aligning vent holes between upper and lower briquettes, particularly for the widely used briquettes with a minimum diameter of 100 mm (commonly known as “coalball” in north China), and may easily lead to serious accidents of fuming and combustion on the surface of a part of or even most briquettes. Accordingly, there is a need of technical measures for solving this potential risk.
Existing lower ignition mode ignites an anthracite briquette with a diameter of 100 mm. The overall cross-sectional area of the vent holes is about 1356 square millimeters as measured and is too small to meet the requirements of burning briquettes with the same diameter of the series of the present invention. Particularly, a pyrophoric briquette (10) with a volatile component of more than 40% and a high oxygen consumption during fast combustion may easily produce dark smoke, which is obviously caused by insufficient ventilation. In addition, a small combustion chamber over the briquette stack will fail to satisfy the complete combustion of a large amount of fuel gases produced by high volatile component content. The two problems must be solved by technical measures to implement an upper ignition mode for a small stove having greatest difficulties in igniting the briquette stack, such that even in a freezing cold weather, a complete combustion of smokeless state in the whole process may be realized from the moment of ignition.
The basic optical-thermal reflecting layer brings the following technical effects: 1. The basic inner circumferential surfaces of the section A stove core inner ring (2) and the flame concentrator (6) can prevent them from being sintered and bonded once they contact high-temperature strong basic slag; 2. The temperature of the inner surfaces of the two can be slightly reduced, thus reducing mullitization; 3. The inner surfaces of the two reflect light and heat to the briquette, which is advantageous to reduce the heat loss due to radial conduction through the outer wall of the stove and to quickly form a high-temperature region in the large combustion chamber (7). Multiple ignition tests proved that for an ignition at an air temperature of 20-25° C., after 1 hour, when the scorching briquette region moves down by more than 150 millimeters, the stove outer wall at corresponding section is only in a slightly warm state of about 30-35° C.; 4. Upon coating, the material liquid can penetrate into the inner wall of the stove core and the inner wall of the flame concentrator by about 2-5 mm to seal the micropores therein. As such, fuel gases containing fine carbon particles with good thermal conductivity coefficient caused by incomplete combustion from radially entering the stove core, thus avoiding radial heat loss; in addition, the gas in the micropores of the stove core can be prevented from radially flowing, thus increasing the effective thermal conductivity coefficient and the average thermal conductivity coefficient of the stove core, and having a significant positive technical effect.
The superior technical features of the selected thermally insulating/refractory materials, especially of the high-whiteness alumina silicate fiber include: a thermal conductivity coefficient down to 0.035 W/m·k, and a volumetric weight down to 0.1; capability of long-term use at 1000° C.; low selling price; and use in high-volume production of section A stove core inner ring (2) and flame concentrator (6) in modules by stove core manufacturers, or use in modifying a stove by cutting prefabricated standard modules into required shapes and sizes and conveniently and quickly combining the modules on site in a building block manner.
According to the requirement of the stove shown in
As for the thermally insulating material (3) filling the space outside the stove core, expanded perlite (or hollow vitrified microbeads) can be selected for low-grade stoves, and flyash floating beads from thermal power plants or hollow glass microbeads from specialized manufacturers (waste glass can partially be used) can be selected for medium/high-grade stoves. Preferably, the particle size of the microbeads is distributed continuously to give a maximized thermal insulating effect.
The technical effects of exemplary stoves, stove cores and assorted briquette stacks confirmed by multiple ignition/combustion tests have completely demonstrated the substantial progress of the novel technical features, and a good industrial practicability can be reasonably predicted.
1 is an iron sheet stove shell, 2 is a section A stove core inner ring, 3 is a stove core outer thermally insulating layer, 4 is a secondary air inlet pipeline, 5 is an air inlet and slag outlet opening, 6 is a flame concentrator, 7 is a large combustion chamber, 8 is a pyrophoric cake, 9 is an underlying briquette, 10 is a pyrophoric briquette, 11 is a straw/charcoal grate, 12 is a vent hole outer ring, 13 is a vent hole inner ring, 14 is a lateral ventilation channel at bottom of straw/charcoal grate (not shown in the figures, please refer to the drawings of the parent patent), 15 is a stove grate, 16 is a top recess of underlying briquette, 17 is a section A stove core outer ring, 18 is a top shelter ring [including cover of stove core outer thermally insulating layer (3), not indicated with size], 19 is a section B stove core, 20 is a conventional thermally insulating/refractory material layer at the stove bottom, 21 is a flame concentrator central torch hole, and 22 is a flame concentrator pressure/volume balance hole
1. After preparing a conventional thermally insulating/refractory material layer (20) at the stove bottom, a stove grate (15) and a section B stove core (19) are placed on the layer. A section A stove core inner ring (2) in its whole or in two semicircles and coated with a thin layer of basic optical-thermal reflecting material on the inner circumferential surface and an A section stove core outer ring (17) of which the inner circumferential surface is coated with a binder and liquid sodium silicate of more than 2.8 modules are bonded and combined to form a section A stove core, which is then placed above the section B stove core. A secondary air inlet pipeline (4) made of iron sheet is mounted, an outer thermal insulating layer (3) of the stove core is applied, and a cover and a top shelter ring (18) are mounted to form an assorted stove for the novel stove core.
2. A flame concentrator (6) according to
3. Two underlying briquettes (9) and one pyrophoric briquette (10) are sequentially added, and the vent holes are aligned according to the method in this disclosure.
4. A pyrophoric cake (8) and a straw/charcoal grate (11) are placed on the pyrophoric briquette (10), and the vent holes are visually aligned. The air inlet and slag outlet opening (5) is adjusted to a position covering about ⅙, ⅕ or ¼ of the ventilation area by using an ash hopper.
5. A small pinched paper strip of about 50 mm long is placed onto the surface of the straw/charcoal grate (11). The pyrophoric cake (8) is easily ignited in a smokeless state. The flame concentrator (6) is mounted and a large torch flame is quickly formed.
6. When the pyrophoric cake (8) is about to burn out or is burnt out in about 2-5 minutes, the flame length is generally shortened, which indicates the key moment for a successful smokeless ignition. At the moment, the straw/charcoal grate (11) is ignited and scorching to play a role in thermal insulation and continuously igniting the surface layer of the pyrophoric briquette (10). Soon the long flame combustion state is restored, and successful ignition becomes a probable event. If the flame is shortened to a greater extent or is about to disappear, the air supply should be reduced immediately. As long as the top vent holes of the pyrophoric briquette (10) are still scorching or have tiny flame, the long flame combustion state can be restored soon. After getting familiar with procedures, flameout will no longer be a concern. The air supply is increased after a few minutes until the firepower meets the requirements.
7. Within 10 minutes, (it can be observed that) the upper layer of the pyrophoric briquette (10) starts scorching at the height of about 5-10 mm, the large combustion chamber (7) also starts scorching, and a high-temperature region above the briquette stack is formed, which indicate that the briquette stack formally comes to a continuous good combustion state.
8. After the briquette stack is burnt out, or the scorching state disappears, the slags are slightly stirred to drop them into the ash hopper. The raw materials and auxiliary materials of the briquette do not contain toxic and harmful substances. The sulfur contained in the raw material is oxidized and neutralized into sulfate salts of calcium, potassium, magnesium, sodium and iron in the course of combustion. The aqueous solution of the slag has a pH of 7-8, and may be used to produce a weak basic compound fertilizer by mixing with the retted green grass fertilizer (if necessary, other fertilizer components such as potassium humate and the like may be added), which is suitable for improving the granular structure and increasing the fertility of acidic clay. The slag of briquette made of a fuel (such as garbage) containing toxic heavy metal elements shall not be used as fertilizer and should be separately disposed.
9. A simple small/micro stove can intermittently employ the smokeless combustible briquette according to steps 1-8; the static-state, smokeless, efficient and clean combustion effect without air supply produces an exhaust gas with a cleaning degree similar to that of natural gas, which contains a lower fraction of nitrogen oxide than natural gas and thus can be directly discharged.
Simple and cheap auxiliary materials, which are arranged inside the chimney and used for collecting trace dust, nitrogen oxides, sulfur oxides and trace volatile organic matters, further improve the cleanness of the exhaust gas close to that of natural gas. Please pay attention to the subsequent patent application of the applicant.
The present invention is illustrated by exemplary stoves, stove cores and shapes of briquette having a diameter of 100 mm with reference to the attached
Please note that another set of subsequent patent applications assorted with the development and application of the present series of technologies, which are smokeless combustion techniques of the present invention integrated applicable to straw power plant, waste incineration power plant and coal-fired thermal power plant with a power of 300 MW or less, such that the plants are converted into centralized heating facilities producing low-pressure steam. Suitable fuels include: bituminous coal, water-containing lignite, weathered coal, peat, coke powder, coal gangue, coal slime, petroleum coke and coal coke containing more than 5% of sulfur, oil shale with high volatile content, straw and other agricultural and forestry wastes, waste plastics, waste rubber wheel and other artificial polymer wastes, waste oil materials, combustible domestic and industrial garbage. As such, a smokeless, efficient and clean combustion in its whole process may be realized.
Number | Date | Country | Kind |
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201910014780.8 | Jan 2019 | CN | national |
201920025966.9 | Jan 2019 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2020/070739 | 1/7/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/143637 | 7/16/2020 | WO | A |
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20080092437 | Helms | Apr 2008 | A1 |
20130112186 | Crichlow | May 2013 | A1 |
20190330550 | Wang | Oct 2019 | A1 |
20210179958 | Wang | Jun 2021 | A1 |
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Number | Date | Country | |
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20220082261 A1 | Mar 2022 | US |