The present application relates generally to the production of chemicals or materials using reactors that are otherwise configured to generate heat and electric power. More specifically, this application relates to an improved cyclone reactor for use in the generation of heat as well as for producing usable by-products that may be used in a variety of applications, such as in the production of calcium carbide (CaC2) or other chemicals.
CaC2 is a basic chemical that has utility in the production of other useful compounds such as acetylene (C2H2), which is commonly used in industrial organic chemistry for producing other compounds such as vinyl chloride or polyvinyl chloride. For example, CaC2 may react with water to form acetylene according to the following formula:
CaC2+2(H2O)→C2H2+Ca(OH)2
There are a number of different ways to produce CaC2. For example, CaC2 may be produced by heating a mixture of lime (e.g., calcium oxide or CaO) and carbon. CaC2 may also be generated in an electric-arc furnace from the reaction of coke and calcium oxide when heated to a temperature ranging from 1600-2100° C. with carbon monoxide as another by-product, as expressed by the following reaction:
CaO+3C→CaC2+CO
CaC2 may also be produced by the direct reaction of coke with calcium oxide and oxygen, with carbon monoxide being produced as a by-product. This reaction is illustrated chemically by the following formula:
It may be desirable to investigate new methods for the production of CaC2, especially in locations where oil reserves are limited and coal resources are plentiful. Methods of producing CaC2, such as using electric arc furnaces, have poor energy efficiency and may also produce potentially detrimental environmental effects. It would be advantageous, for example, to produce CaC2 or other carbon-based chemicals using a more efficient and more environmentally friendly method that relies on existing coal reserves. Especially advantageous would be a process where less expensive relative low-quality coal (i.e. coal with a low specific heat value) could be employed as a reactant.
One embodiment of the present application relates to a cyclone reactor for producing a usable by-product as part of a recoverable slag layer. The reactor may comprise a housing having an outer wall that defines a combustion chamber, an inlet configured to introduce a reactant into the reactor, a burner configured to combust the reactant in a flame zone near a central axis of the chamber, and an outlet configured to provide for the removal of the usable by-product from the housing. The reactor is configured to combust a first portion of the reactant in an exothermic reaction in the flame zone, and the reactor is configured to convert a second portion of the reactant in an endothermic reaction near the outer wall to produce the by-product as part of the slag layer.
Another embodiment of the present application relates to a method for producing a usable by-product in a cyclone reactor. The method may comprise introducing a reactant into a housing of the reactor through an inlet, using a burner to combust a first portion of the reactant in an exothermic reaction provided in a flame zone near a center of the housing, consuming a second portion of the reactant in an endothermic reaction near an outer wall of the housing to produce the by-product as part of a slag layer; and removing the slag layer including the by-product through an outlet in the housing. The endothermic reaction may take place at a temperature of at least 1600° C.
According to an exemplary embodiment, an improved and modified reactor (e.g., a cyclone burner or reactor) may be used for producing chemicals or materials, such as carbon-based chemicals, including, but not limited to calcium carbide (CaC2), lithium carbide (Li2C2), sodium carbide (Na2C2), potassium carbide (K2C2), magnesium carbide (Mg2C3 or MgC2). The improved reactor may advantageously allow for the production of such chemicals or materials using modified versions of existing technology using readily-available raw materials to produce chemicals for broad applicability.
Conventional cyclone burners are commonly used in coal-fired electric power plants, where coal having low ash melt temperatures is combusted for the generation of heat and electric power. Such cyclone burners, however, are typically operated at temperatures of between approximately 1200° C. and 1600° C. In contrast, to achieve the carbothermic reduction of calcium oxide (CaO) to CaC2 that takes place at temperatures above 1600° C., hot gas and flame temperatures of 1600-2500° C. are necessary, which makes conventional cyclone burners used in coal-fired power plants particularly unsuitable.
According to an exemplary embodiment, a partial oxidation scheme is used to produce the chemicals, such that the reactants (e.g., lime and coal) are introduced into the system as solids and conveyed into the reactor using one or more inlets at suitable placements and inlet conditions. The reactor may be configured to operate in a gas staging mode of operation, where a first portion of the reactant (e.g., carbon) is combusted, such as with additionally introduced oxygen (or air), in an exothermic reaction to produce carbon monoxide and carbon dioxide (inducing the high reaction temperatures). A second portion (e.g., the remaining portion) of the reactant (e.g., carbon) then is consumed or converted in an endothermic reaction with the CaO to produce CaC2 and CO, receiving the necessary energy input, such as through radiative heat transfer, from the combustion of the first portion of the reactant. The two reactions (e.g., exothermic, endothermic) in the reactor may occur substantially simultaneously or may occur independently with respect to time, and may take place in two different regions or locations in the reactor. The former exothermic reaction that induces the high reaction temperatures may take place in the center of the reactor near a central longitudinal axis of the reactor, such as in the flame zone region, within an oxidizing atmosphere. The latter endothermic reaction that produces a usable by-product (e.g., CaC2) from CaO may occur in an at least partially liquid (or molten) slag phase, such that the slag forms a layer provided along the inside surface of the wall of the reactor in a reducing atmosphere. The liquid slag layer including the CaC2 may then be recovered from the reactor to be subsequently used, for example, in the production of acetylene or for any other desired use.
According to an exemplary embodiment, an improved cyclone burner allows for the production of usable by-products as well as heat and electric power. Such an improved cyclone burner differs in several respects from conventional cyclone burners currently used. First, the reactor is configured to operate in a gas staging mode of operation, in which there are two separated gas zones within the reactor during operation. The first gas zone is a combustion or flame zone, which may be located substantially along the reactor axis where oxidizing conditions exist to fully (or substantially) combust a first portion of reactant (e.g., carbon) to form carbon-dioxide (CO2) to make full use of the coal heat content to achieve high temperatures in this zone. The second gas zone occurs away from the first zone, such as close to the outer wall of the reactor, and is a reducing zone that enables the formation of calcium carbide (CaC2) as part of a slag layer. The heat transfer from the first zone (i.e., the combustion zone) to the wall slag layer mainly occurs through radiant heat transfer, providing the high temperatures that facilitate the consumption of a second portion of the reactant (e.g., carbon) and the endothermic reaction that produces the by-product (e.g., CaC2). It is preferred to minimize the mixing between the two gas zones to ensure stable gas layering (e.g., stratified flow). Accordingly, the mixing between the two gas zones may be controlled (e.g., reduced, minimized), for example, by tailoring the swirl and axial gas flow characteristics (e.g., velocities) within the reactor.
Second, the aspect ratio (i.e., the ratio of the length to the diameter) of the reactor is larger than in conventional cyclone burners to provide a longer centerline flame zone to allow for enough residence time of the reactants (e.g., CaO, C) to achieve the high wall temperatures and to complete the reaction to form the usable by-product, such as CaC2.
Third, a flue gas recycle stream having preferably a CO-rich fraction may be introduced into the reactor, such as through an inlet, to support the reducing reaction conditions at the reactor wall in order to promote the carbide formation reaction.
Fourth, the pulverized coal burner configured within the reactor (e.g., along the reactor axis) may be optimized to allow more efficient mixing of the fuel, such as C or CaO if the reactants for the carbide reaction are not fed separately, and oxygen (and/or air) to facilitate faster heat release and a higher flame temperature to provide, such as to provide a stoichiometric ratio of the centerline flame zone as close to one (1) as possible. For example, the particle diameter of the pulverized coal may be reduced prior to being fed into the reactor. Smaller particle size of the coal may prolong suspension of the particles in the gas phase, which may provide for more efficient particle deposition downstream in the reactor.
In addition to the foregoing, the inventors have also found it advantageous to use smaller sized particles of reactants in the reactors disclosed herein compared to the particles used with conventional cyclone burners. The use of the smaller sized particles of reactants for the burner helps facilitate faster heat release to achieve the high wall temperatures required to produce the usable by-product.
Alternatively, the co-feeding of the reactants and oil into the burner of the reactor, such as being fed along the reactor axis or flame zone, may be utilized to facilitate the formation of the by-products. Another alternative is to use oil alone as the reactant input into the reactor. Small droplets of oil, such as oil droplets having diameters less than 100 μm, may be produced and fed into the flame zone of the burner to fuel the reaction. Small oil droplets may easily be produced using standard atomizing nozzles, as opposed to producing coal particles of that size which may involve energy-intensive comminution processes. Relative smaller droplet or particle size results in faster heat release, which in turn results in more efficient heat transfer to the wall, thereby creating the higher wall temperatures that are essential for the carbide generation reaction to proceed. Since gas residence time and therefore heat transfer efficiency may be especially critical with small-scale (or pilot installations) of the process, the oil co-firing may be especially advantageous therein, while conversely, in large-scale applications of the technology, oil co-firing may not be as advantageous.
Additionally, prior to being fed into the reactor, the coal may be processed to reduce the moisture content in the coal, such as through a coal-drying process, to increase the effective heat content of the coal. As another alternative, a higher quality (higher heat content) coal may be used.
As shown in
The system may further include additional devices or components as well, some of which are illustrated in
As shown in
The reactor 104 may include several inlets configured to introduce a reactant or other material into the reactor 104. As shown in
The reactor 204 includes a substantially cylindrical housing 205 having a first end 251 (e.g., an input end) and a second end 252 (e.g., an output end), a first inlet 206 (e.g., a primary inlet), a second inlet 207 (e.g., a secondary inlet), and a burner 208. According to an exemplary embodiment, the first inlet 206 and the burner 208 are provided at the first end 251 of the reactor 204. The first inlet 206 is configured to be connected (e.g., coupled) to the burner 208, and is configured to supply the burner 208 with reactant(s) and/or co-reactants. The coupled first inlet 206 and burner 208 may be connected to the first end 251 of the housing 205, and the burner 208 may be aligned with a central longitudinal axis 253 of the housing 205. This arrangement may produce a flame zone that extends from the burner 208 through a central portion of the housing 205 along the central longitudinal axis 253. As shown, the second inlet 207 is configured to be connected to an outer wall 250 of the housing 205 between the first end 251 and the second end 252 of the housing 205. The second inlet 207 is configured to introduce reactants and/or co-reactants into the housing 205.
The housing 205 of the reactor 204 may be substantially cylindrically or barrel shaped having an outer wall 250 and a central longitudinal axis (e.g., mid axis) 253, where the outer wall 250 extends from a first end 251 to a second end 252. The housing 205 defines a chamber 254 (e.g., a combustion chamber) in which the gas staging conditions or operations are configured to occur therein. The first and second ends 251, 252 of the housing 205 may be configured to have any suitable shape. For example, the first end 251 may be cone-shaped.
The housing 205 may be configured to extend horizontally, and/or may be tapered (e.g., inwardly or outwardly from the first end to the second end). The housing 205 also may be configured at an inclination angle relative to horizontal with the lower end at the slag outlet (second end 252) to influence the slag flow. According to other embodiments, the housing may be arranged at an inclination angle with the lower end at the first end or may configured to extend in a vertical direction. Where the housing 205 has a tapered wall, an oblique wall, or is configured at an angle of inclination, the housing may influence flow velocity and/or residence time of the slag layer 213, such as by utilizing gravity. In addition, the housing 205 may be configured to be fixed, such as fixed on the central longitudinal axis 253, or may be configured to move. For example, the housing 205 may be configured to rotate about the central longitudinal axis 253. Also for example, the housing 205 may be configured to oscillate or vibrate, which may help influence the reactions in the housing, such as by influencing the flow of the slag layer 213 in the housing 205.
The outer wall 250 of the housing 205 may include one or more than one layer of material. For example, the outer wall 250 of the housing 205 may include an outer layer configured to provide strength and durability to the housing 205 and an inner layer configured to resist the extremely high temperatures (e.g., 1600-2500° C.) that occur within the reactor 204. The outer layer of the outer wall 250 of the housing 205 may be made from steel (or other suitable high strength material) and the inner layer of the wall 250 of the housing 205 may be made from a refractory material or metal, such as niobium (Nb), molybdenum (Mo), tantalum (Ta), tungsten (W), zirconium (Zr) or rhenium (Re), and/or alloys or combinations thereof that may advantageously exhibit relatively high temperature resistance. The inner refractory layer may also be made from other insulating materials, such as silicon or silicon based compound, or from ceramics (e.g., zirconium dioxide, aluminum oxide, magnesium oxide, yttrium oxide, silicon carbide, silicon nitride, boron nitride, mullite, aluminum titanate, tungsten carbide). The inner refractory layer may be configured as a cladding or lining covering the inner surface of the outer layer, may be formed as a separate tube and then provided within and adjacent to the outer layer, or may be configured in any suitable manner. It should be noted that the outer and inner layers may be made from other suitable materials or methods, and those materials and methods disclosed herein are not intended as limiting.
In addition to the refractory, the reactor 204 may also utilize the formation of the slag layer 213 as another way to shield the outer wall 250 of the housing 105 from the high temperatures in the reactor 204 during operation. As the deposition of slag forms along the inner surface of the outer wall 250, both an inner molten layer 213b (e.g., melt film layer) and an outer solidified layer 213a form, where a self-insulation effect may occur as a result of the solidified layer 213a. The solidified layer 213a may reduce the effective temperature close to the outer wall 250 relative to the high temperatures at the core of the reactor 204. This self-insulating effect may protect the material(s) that forms the outer wall 250.
The housing 205 may further include one or a plurality of tubes 256 that are configured to circumscribe at least a portion of the outer wall 250 of the housing 205. The tubes 256 may be configured to carry a fluid (e.g., water, oil, air) that may be used to regulate the temperature of the outer wall 250 during operation of the reactor 204, such as to cool the outer wall 250. According to an exemplary embodiment, a plurality of tubes 256 may be annular in shape to wrap around the circular shape of the housing. In this arrangement, the plurality of tubes 256 may have a side-by-side arrangement around the housing. According to another exemplary embodiment, a tube 256 may have a helical shape and may be configured to wrap and wind around the outer wall 150 of the housing 205.
As shown in
The fluid may be directed into the tube(s) 256 from a temperature regulating device, such as a heat exchanger. Further, the fluid may exit the tube(s) 256 and pass back into the temperature regulating device to form a thermodynamic cycle. Thus, for example, the fluid may absorb heat from the outer wall 250 of the housing 205 as the fluid passes over the wall 250, conducting some of the heat to the wall of the respective tube 256. The heat in the wall may then be absorbed by a second fluid (e.g., air) passing over the respective tube 256 through convection, while the heat remaining in the first fluid may be absorbed by the temperature regulating device.
As shown in
The housing 205 may include an opening 258 or a plurality of openings to introduce reactants (and co-reactants when used) and to remove usable by-products and other materials formed during operation. As shown in
Also shown in
According to an exemplary embodiment, the first inlet 206 is configured to convey or transfer the primary reactants (e.g., pulverized coal, pulverized lime, air, oxygen) to a location where the burner 208 is able to ignite the reactants in the combustion chamber of the housing 205. The first inlet 206 may be provide as a pipe or hollow tube member that defines a passageway for the reactants to flow therein, such as from an input assembly of the system. The first inlet 206 may extend in a substantially linear direction (e.g., vertical), a non-linear direction (e.g., arcuate), or any suitable direction that can transfer the reactants to the reactor 204 to facilitate the reaction in the housing 205.
The first inlet 206 may be formed of any suitable material that is strong and durable enough to allow for the repeated conveyance (or transfer) of material (e.g., reactants) through the inlet and into the reactor 204. The first inlet 206 may include a first end connected to the burner of the reactor 204 (or directly to the housing 205 adjacent to the burner), and a second end that is connected to a device (e.g., an input assembly) that feeds the primary reactants into the first inlet 206. The first inlet 206 may include a damper or other device configured to regulate or adjustably control the flow rate of the reactants into the housing 205. Thus, the first inlet 206 may introduce the primary reactants into the burner at a controlled (and adjustable) flow rate to fuel the reaction within the reactor 204 in a controlled manner. The first inlet 206 may be configured to have an adjustable pressure to produce an adjustable velocity that pushes the reactants through the inlet and into the reactor 204.
The burner 208 may be cylindrically shaped and configured to connect to the first end 251 of the housing 205, such that the burner 208 is aligned substantially with the central longitudinal axis 253 of the housing 205 and reactor 204. The burner 208 is configured to produce a flame zone 211 for the purpose of combustion of a first portion of the reactants (e.g., the primary reactants) in an exothermic reaction within the reactor 204. As shown in
According to an exemplary embodiment, the second inlet 207 is configured to introduce (e.g., convey, transfer, etc.) a fluid (e.g., secondary air, oxygen) into the reactor 204 from a source, such as an input assembly. In other words, the second inlet 207 may introduce one or more additional (or secondary) reactants into the reactor 204. The second inlet 207 may be provided as a pipe or hollow tube member that defines a passageway for the fluid to flow therein.
The second inlet 207 may connect to the outer wall 250 of the housing 205 between the first and second ends of the housing 205, or may be configured to connect anywhere on the housing 205. As shown in
The oxygen supply of the second inlet 207 or gas feed may be tightly controlled to prevent consumption of the carbon prior to generation of the carbide reaction. If not tightly controlled, under the conditions for the carbide reaction, the carbon may burn to carbon monoxide, such that the carbon for the carbide reaction may be consumed before initiation of the carbide generation. Thus, there may be some over-stoichiometric amount of carbon in the deposition zone or in the reactants introduced through the second inlet 207 so that some carbon monoxide can be produced. The carbon monoxide by the incomplete combustion, as well by the carbide reaction, can then burn completely or at least partially to carbon dioxide when mixed with oxygen in the inner or central region of the reactor 204, such as in the exothermic reaction region.
To further control and/or influence the complex demand and reaction conditions in the reactor 204, a third inlet (e.g., supply) may be provided. As shown in
The reactor 204 may further include an outlet 210 (e.g., a slag outlet) configured to facilitate the removal of the slag material or the slag layer 213 along with one or more than one by-product (e.g., CaC2) from the reactor 204, such as from the housing 205. As shown in
The fluid (e.g., primary, secondary, tertiary) used in the inlets (e.g., first, second, third) may be air, oxygen, or a combination thereof, or may include recycled flue gas from the reactor 204, such as a CO-rich fraction of flue gas that would aid in creating the reducing atmosphere needed for carbide-generation reaction along the outer wall 250 of the housing 205 of the reactor 204. For example, recycled flue gas may be cooled, compressed, then reheated prior to reintroduction into the reactor 204. Also, the recycle flue gas may be extracted from the reactor 204 through an additional gas-outlet, such as the second outlet opening 258d in the housing 205. Alternatively, the additional gas-outlet may be configured close to the outer wall 250 of the housing 205 or may be configured anywhere on the housing 205. Furthermore, the second inlet 207 and/or third inlet 209 may be used to feed a fraction of the reactants (e.g., CaO, C, coal) to influence the location and the homogeneity of the particle deposition, or the rate of deposition, along the outer wall 250 of the housing 205. Computer simulation (e.g., CFD analysis) suggests that if deposition occurs too early in the process, then the deposition rate at the downstream section of the reactor 204 may be reduced. In the extreme case, a reduced deposition may leave a portion of the reactor 204 uncovered by slag, which may prove detrimental to the wall refractory over time by reducing the durability (e.g., longevity) of the uncovered refractory. The deposition rate downstream may also be influenced by the third inlet 209. For example, the third inlet 209 may be configured to support or provide tangential distribution and/or the axial transport of the deposition layer to promote downstream deposition along the outer wall 250.
The primary reactants (e.g., air, oxygen, pulverized coal, and pulverized lime) are transferred at a controlled flow rate through the first inlet 206 into the reactor 204 where the burner 208 initiates combustion of some of the primary reactants creating a flame zone 211 that passes through the center region of the hollow reactor 204, such as along the central longitudinal axis 253 of the housing 205. A first portion (e.g., some of the particles) of the reactant (e.g., carbon from the coal) reacts with oxygen in the oxidative atmosphere of the flame zone 211 in an exothermic reaction that generates very high temperatures as well as by-products such as carbon monoxide and carbon dioxide. The fluid and/or second fluid (e.g., air, oxygen, recycled flue gas, combination thereof) enters the reactor 204, such as along the outer wall 250 in a direction substantially tangential to the flame zone 211 of combusting reactants, with a velocity that induces swirl within the reactor 204 thereby creating centrifugal forces that distribute the particles of carbon and CaO along the inside surface of the outer wall 250 of the housing 205 of the reactor 204. A second portion (e.g., some of the particles) of the reactant (e.g., carbon and CaO) that deposit along the outer wall 250 reacts in the reducing atmosphere, such as in the slag layer 213, in an endothermic reaction that produces a usable by-product (e.g., CaC2). The tangential velocities created by the fluid from the second inlet 207 and the axial velocities created by the flame zone 211 (e.g., primary air, tertiary air) and/or the second fluid from the third inlet 209, combined with gravitational forces, enable the liquid slag layer to flow along the inside surface of the outer wall 250 of the reactor 204. The slag layer 213 (e.g., liquid slag layer) including the usable by-product (e.g., CaC2) then may be removed, such as through the outlet 210 of the reactor 204 to be processed to recover the useable by-product (e.g., CaC2) from the slag material.
The feed of auxiliary material into the reactor 204 may be necessary to influence or control the slag melting temperature. Melting temperatures that are too high may inhibit the formation of the liquid slag layer, while melting temperatures that are too low may inhibit the reaction that produces the carbide generation as well as may allow for the formation of a liquid layer that is too thin, which induces high liquid velocities and low residence time. The melting temperatures of CaO and CaC2 are relatively high (e.g., about 2600° C. and about 2300° C. respectively). Thus, a eutectic mixture of both CaO and CaC2 having a mass ratio of about 1:1 is preferable, since it may supply a minimum melt temperature of about 1810° C., which is in the desired temperature range (e.g., 1600-2500° C.).
As shown in
The formation of the slag layer 213 may be influenced or tailored, such as through the introduction of materials (e.g., additives) that effect the characteristics (e.g., melt, flow, etc.) of the slag layer. For example, melt promoting additives may be introduced into the reactor 204 to promote the formation of the slag layer 213 in the reactor 204 during its operation so that the carbothermic reaction can be carried out at lower temperatures in a melt. As another example, the additives may serve as fluxants configured to lower the melting of ash and lower the temperature at which dissolution of the CaO occurs in the melt. The fluxant additives may be configured to promote the flow of the melt, such as by influencing (e.g., decreasing) the viscosity of the slag layer 213, such as the liquid melt film layer 213b, to allow the carbon to move more freely in the liquid layer, which may speed up the reaction between the carbon and the CaO to promote the production of the CaC2. As another example, catalytic additives may be introduced into the reactor 204 to accelerate the formation of the by-product (e.g., CaC2) in the melt as part of the slag layer 213. The presence of CaC2 in the slag layer 213, such as in the liquid melt film layer 213b, may serve to promote the chemical reaction that forms additional compounds of CaC2. In this case, the input reactant being fed into the reactor 204 may be doped with CaC2 in order to serve as a catalyst in the formation of CaC2 in the slag layer 213 near the outer wall 250 of the housing 205 during the endothermic reaction. The initial presence of CaC2 in the reactor 204 may also form a eutectic mixture thereby lowering the melt temperature to promote the formation of CaC2. The additives (e.g., melt promoting, fluxants, catalysts) may be fed into the reactor, such as through an inlet (e.g., first, second, third) of the reactor as reactants or co-reactants. The additives may comprise minerals, elements, or any suitable compound (e.g., silica, alumina). Examples of catalytic additives may comprise a carbide (e.g., CaC2), an oxide (e.g., manganese oxide), and/or certain metals (e.g., copper). Examples of promoting additives may comprise, among others, non-volatile alkali and alkaline earth metal oxides, hydroxides, and/or carbonates (e.g., potassium, sodium, strontium, barium).
The reactor 304 of
For the CFD model of Example 1 of the reactor 304, coal, calcium oxide (CaO), and primary combustion air enter the first inlet opening 358a of the housing 305 from the first inlet 306 at a location that is adjacent the scroll burner 308 at the first end 351 of the housing 305. A fluid comprising secondary air enters the housing 305 through the tangentially configured second inlet 307 adjacent the outer wall 350 of the housing 305. A second fluid comprising tertiary air enters the housing 305 through first inlet opening 358a along the central longitudinal axis 353. During the computational analysis run of the reactor 304, a first portion of the coal particles is combusted while moving in suspension in the flame zone along the central longitudinal axis 353, and a second portion of the coal particles becomes deposited on the inside surface of the outer wall 350 together with CaO due in part to the centrifugal acceleration induced by the swirling motion in the reactor 304. The reactor 304 is equipped with a studded (cooled) wall section close to the second inlet 307, and the remainder of the wall 350 is refractory lined.
It should be noted that this CFD model takes into consideration only coal combustion and was modeled to mainly establish reaction conditions appropriate for calcium carbide (CaC2) generation as part of the slag layer along the outer wall of the housing. The complex fluid dynamics, mass transfer and reaction phenomena governing carbide generation in the slag layer was not captured by the CFD model and therefore was considered separately in a separate example (multi-scale modeling approach) discussed below. Accordingly, the main output of the CFD model of Example 1 was the wall temperature distribution which serves as an input for the film calculations used in the one-dimensional model of Example 2. The results (i.e., the output) of the CFD model of Example 1 are provided in Table 2 below.
To assess the calcium carbide generation as part of the slag layer along the outer wall, the local wall temperature distribution over the reactor length was evaluated in the CFD model of Example 1.
The one-dimensional model of Example 2 was performed to evaluate the predicted results pertaining to the fluid dynamics, heat transfer, mass transfer, and reaction kinetics in the reactor for generating the CaC2 in the slag layer. To simplify the modeling, the reactor shown in
It should also be noted that the reactor may be configured to produce other useful by-products instead of or in addition to calcium carbide (CaC2), including, but not necessarily limited to other carbides formed from the elements of groups one and two in the periodic table, such as lithium carbide (Li2C2), sodium carbide (Na2C2), potassium carbide (K2C2), and magnesium carbide (Mg2C3 or MgC2). For example, the reactor may be configured to produce sodium carbide (Na2C2) and carbon monoxide from sodium oxide (or sodium carbonate) and carbon. Sodium carbide can be reacted with water to produce acetylene and sodium hydroxide. It is also believed that other acetylides may be formed within the reactor from the transition metal elements (e.g., group 11 of the periodic table), from the metal elements (e.g., group 12 of the periodic table), from lanthanoids (e.g., lanthanum (La), cerium (Ce), praseodymium (Pr), terbium (Tb)), steel, metallic silicon, aluminum, or other carbides. For example, copper carbide (Cu2C2) or zinc carbide (ZnC2) may be able to be formed from within the reactor. Also, the reactor may be fed with bio-derived carbonaceous materials, such as biomass, biocoal, biochar, or a combination thereof, to produce bio-derived chemicals, such as bio-derived carbides. According to other exemplary embodiments, the systems and techniques discussed herein may be used to facilitate other reduction reactions, such as the reduction of iron oxides to elemental iron.
As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.
It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).
The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.
It is important to note that the construction and arrangement of the reactors as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.
This application is a Divisional of U.S. Non-Provisional patent application Ser. No. 13/400,528, which was filed on Feb. 20, 2012, which claims the benefit of and priority to U.S. Provisional Patent Application No. 61/444,944, which was filed on Feb. 21, 2011. The entire disclosures of aforementioned U.S. patent applications are incorporated herein by reference.
Number | Date | Country | |
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61444944 | Feb 2011 | US |
Number | Date | Country | |
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Parent | 13400528 | Feb 2012 | US |
Child | 14270055 | US |