This application relates generally to the production of heat and usable chemicals, materials, or by-products using venturi-type reactors that are otherwise configured to produce carbon black. More specifically, this application relates to an improved reactor (e.g., a venturi 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 1500-2100° 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) or a waste biomass with a low specific heat value could be employed as a reactant.
One embodiment of this application relates to a process for producing a usable product in a reactor. The process comprises introducing co-reactants comprising a fuel source and oxygen into a first section of the reactor through at least one inlet, wherein the fuel source comprises carbon. The process further comprises combusting at least a portion of the fuel source and oxygen in an exothermic reaction in the first section, wherein a burner is provided to generate a flame to combust the fuel source and oxygen. The process further comprises transferring the co-reactants through a second section of the reactor, the second section including a throat having a size that is smaller than a size of the first section, such that a vacuum is induced and a velocity of the co-reactants increases through the reactor. The process further comprises transferring the co-reactants into a third section of the reactor that is downstream from the throat, the third section including an inner wall having a size that is greater than the size of the throat. The process further comprises depositing at least a portion of the uncombusted carbon and a metal oxide along the inner wall of the third section, wherein the metal oxide is introduced into at least one of the first, second, and third sections of the reactor. The process further comprises converting the deposited metal oxide into the usable product in a carbothermic reduction reaction within a molten slag along the inner wall, wherein the carbothermic reaction occurs at a temperature of at least 1600° C. The process may further comprise recovering the molten slag containing the usable product from the reactor.
The size of the throat may be configured to decrease when moving from a first end of the throat that is adjacent to the first section to a second end of the throat that is adjacent to the third section of the reactor. The size of the throat may be configured to decrease at a constant rate and continuous manner from the first end to the second end of the throat.
The at least one inlet may include first and second inlets, wherein each of the first and second inlets is tangentially aligned relative to the first section in a direction that is transverse and offset from a longitudinal axis of the reactor to swirl the co-reactants introduced into the first section. At least one of an additive, a carbide, a residual oil, and a calcium source may be introduced into the third section of the reactor through a third inlet, to promote the formation of the molten slag along the inner wall.
A compound comprising at least one of an additive, a carbide, a residual oil, and a calcium source may be introduced into the second section of the reactor through a secondary inlet.
The molten slag may be recovered from the reactor through a first outlet. The reactor may optionally include a second outlet through which off gases are removed from the reactor.
The conversion of the metal oxide to the usable product may occur by reacting the deposited metal oxide with carbon, where the carbon is from at least one of the fuel source, combustion off gas, and another co-reactant introduced into the first section.
The usable product may include a carbide that comprises at least one element from at least one of groups one and two of the periodic table.
Another embodiment relates to a process for producing a usable product in a reactor. The process comprises introducing co-reactants into a first chamber defined by a cylindrical first section having an inner diameter, where the co-reactants comprise at least a fuel source and oxygen, the fuel source comprising carbon. The process further comprises combusting at least a portion of the fuel source and oxygen in the first chamber using a burner in an exothermic reaction; and transferring the co-reactants from the first chamber to a second chamber fluidly connected therewith. The second chamber is defined by a second section that extends between first and second ends, and a size of the first end is smaller than the inner diameter of the first section. The process further comprises transferring the co-reactants from the second chamber to a third chamber fluidly connected therewith, where the third chamber is defined by a cylindrical third section having an inner diameter that is larger than a size of the second end. The process further comprises forming a molten slag in the third chamber by carbothermic reduction of uncombusted carbon and a metal oxide, where the metal oxide is introduced into at least one of the first, second, and third chambers. The molten slag contains at least a portion of the usable product. The difference between the size of the first end and the inner diameter of the first section and between the size of the second end and the inner diameter of the third section influences a velocity and a temperature to promote the carbothermic reduction of the uncombusted carbon and the metal oxide.
The size of the first end may be the same as the size of the second end, such that the second section has a constant size throughout. The second section may be cylindrically shaped having a constant inner diameter that is smaller than the inner diameters of both of the first and third sections.
The size of the first end may be larger than the size of the second end, such that the size of the second section progressively narrows moving from the first end to the second end. The second section may be frusto-conical shaped.
The first end may be connected to the first section through a first side wall, and the second end may be connected to the third section through a second side wall.
The usable product may comprise at least one element from at least one of group eleven of the periodic table, group twelve of the periodic table, and lanthanoids. The conversion of the at least one element to the usable product may occur by reacting the deposited elements with carbon, where the carbon is from at least one of the fuel source, combustion off gas, and another co-reactant introduced into the first section.
Yet another embodiment relates to a process for producing a usable product in a venturi reactor. The process comprises introducing co-reactants into a first chamber, where the co-reactants comprise carbon and oxygen. The process further comprises combusting at least a portion of the co-reactants in the first chamber, and transferring the co-reactants from the first chamber to a second chamber, where the second chamber is configured as a continuously uninterrupted tapered body to increase a velocity of the co-reactants. The process further comprises transferring the co-reactants from the second chamber to a third chamber, wherein uncombusted carbon and a compound react in a molten slag to form usable product. The compound is introduced into at least one of the first and third chambers of the reactor, and the compound comprises at least one of an oxide, a hydroxide, and a carbonate.
The compound and uncombusted carbon may react within the molten slag in a carbothermic reduction reaction at a temperature of at least 1600° C. The molten slag may form along an inner wall of the reactor. The compound may be introduced into the first chamber. A second compound comprising at least one of an additive, a carbide, a residual oil, and a calcium source may optionally be introduced into the third chamber of the reactor in order to further promote the carbothermic reaction in the third chamber.
The carbon may be a hybrid fuel source comprising carbon from a biomass and carbon from a non-biomass carbon source.
The second chamber may be configured as a linear tapered body that is continuous and uninterrupted along the entire body.
Referring generally to the Figures, disclosed herein are reactors (e.g., venturi-type carbon black reactors) and processes for producing products (e.g., chemicals, materials, etc.). For example, the reactors and processes, as disclosed herein, may produce 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 reactors and processes, as disclosed herein, may include a casing defining a chamber that includes a feature (e.g., a throat, a venturi, etc.) that is configured to induce a vacuum in the chamber to influence the turbulence and the temperature to promote carbothermic reduction of reactants introduced into the chamber. Thus, the reactors and processes, as disclosed herein, may be configured to produce heat and usable products.
Venturi reactors are used in carbon black production plants, where typically natural gas is combusted in air, oxygen enriched air, or pure oxygen for the purposes of generating high temperature combustion gases in which excess fuel or additional carbonaceous “make” (e.g., an aromatic oil) is injected and thermally decomposed into fine particles of carbon black and hydrogen off-gas. Such venturi reactors, however, are not operated in a slagging mode with the injection of metal oxides to achieve carbothermic reduction of, for example, calcium oxide (CaO) to CaC2 that takes place at temperatures above 1500° C. in a liquid molten slag media. Preferably, the carbothermic reduction reaction occurs at a temperature of at least 1600° C. in the molten slag.
As shown in
The casing 101 of the reactor 100 may include one or more than one wall that defines the one or more than one chamber 102 (e.g., a combustion chamber) inside the casing 101. As shown in
The casing 101 may include one or more sections that are configured to define the one or more chambers inside the reactor 100. Each section of the casing 101 may be generally defined by a portion of the outer wall 114 and/or the inner wall 115. As shown in
As shown in
As shown in
The second section 122 of the casing 101 may be configured to extend from the first section 121 generally in a horizontal direction, at an inclination angle relative to horizontal, or in a vertical direction. For example, the reactor may be vertically configured, such that the first section is provided above (or below) the second and/or third sections. The vertically aligned reactor having the combustion zone or section disposed above the downstream sections may be configured to utilize gravity to induce the slag layer (including the usable product) to flow or run down the reactor, such as to allow recovery of the usable product through a tap disposed at the bottom of the reactor.
As shown in
The casings of the reactors, as disclosed herein, may be configured to include one or more than one layer. For example, the casing may include an outer structural layer (e.g., an outer wall) made from a material, such as steel or another suitable high strength material, that is configured to provide the strength and durability to the casing. The casing may also include more than one outer structural layers Also, for example, the casing may include an inner layer (e.g., an inner wall) in the form of an inner refractory layer that is configured to withstand the high temperatures (e.g., 1500-2500° C.) that occur within the reactor, such as during the combustion process. For example, the casing may include an inner refractory layer that is 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, chromium oxide). 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 is 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.
Furthermore, the inner layer of the casing may be made from more than one refractory material. For example, the inner layer (e.g., wall) of the first section 121 of the casing 101 may include a first refractory material, and the inner layer of the second section 122 of the casing 101 may include a second refractory material. The second refractory material may have a higher or lower temperature resistance compared to the first refractory material, such as to tailor the heat resistance of certain regions of the casing to the temperatures that the regions are expected to be subjected to during operation (e.g., combustion) of the reactor. Also, for example, the inner wall of the third section 123 may include a third refractory material that is different than the first and/or second refractory materials to further tailor the heat resistance of the reactor 100. Thus, the different regions of the casing may include different refractory materials, which may be tailored to withstand different temperature levels. They may also may be configured to withstand different level of corrosive environments. For example, a different refractory material may be employed in regions where no ash-bearing material is present (e.g., in the first section 121 or first section 102a of the chamber 102), compared to regions where ash-bearing materials are present, such as in the third section 123 of the casing 101 or third section 102c of the chamber 102 where slag (e.g., a molten slag layer) is formed along the inside of the inner layer of the reactor.
As shown in
As shown in
The reactors, as disclosed herein, may further include a device to help regulate (e.g., control, influence, etc.) the temperature of the casing. For example, the reactor may include one or more tubes that are configured to circumscribe at least a portion of the casing to regulate (e.g., control, influence, etc.) the temperature of the casing. As shown in
The fluid may be directed (e.g., forced) into the tube(s) from a temperature regulating device, such as a heat exchanger. Further, the fluid may exit the tube(s) 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 of the housing as the fluid passes over the wall, conducting some heat away from the wall and into the fluid. The heat remaining in the first fluid may then be absorbed by a downstream temperature regulating device, which may consist of another heat exchange arrangement (e.g., a second heat exchanger) where a second fluid is heated by cooling of the first fluid.
As shown in
The burner 103, regardless of orientation within the reactor, is configured to provide a flame that is configured to combust the reactant(s) in a flame zone. The burner 103 may be provided at locations other than the first end 117 of the casing 101 and initiate combustion of the reactant(s) in the first section 102a or another section of the chamber. The flame zone produced by the burner 103 may be configured to extend beyond the first section 102a into the second section 102b of the chamber 102 to continue combustion therein. The burner 103 may be aligned near a central axis of the chamber relative to the inner wall 115 to allow the flame to extend toward or into the second section of the chamber, such as generally along the longitudinal axis LA. As shown in
The first inlet 111 is configured to introduce a first reactant, such as air or fuel, into the reactor, such as the first section 102a of the chamber 102 of the reactor 100. According to an exemplary embodiment, the first inlet 111 is configured to introduce a non-ash bearing fuel source, such as natural gas, into the reactor 100. Using a non-ash bearing fuel as a reactant may advantageously prevent the buildup of solid materials, such as carbonaceous material (e.g., soot, ash, etc.), slag, or minerals. For example, introducing non-ash bearing fuel reactants may prevent the buildup of materials in the combustion section or near the throat. According to another exemplary embodiment, the first inlet 111 is configured to introduce biomass as the fuel, which may be a non-ash bearing biomass. The non-ash bearing biomass may be a liquid (e.g., condensed pyrolysis oils or pyrolysis tars) and/or a gas (e.g., flammable pyrolysis gases containing carbon monoxide, hydrogen, methane, etc.). According to yet another exemplary embodiment, the first inlet 111 may introduce a hybrid fuel, such as, for example, a combination of natural gas and biomass. The first inlet 111 may be configured to introduce an ash bearing fuel source into the reactor 100. Other fuel sources, including ash-bearing fuels, may be introduced into the reactor through the first inlet 111.
The first inlet 111 may be configured to introduce multiple co-reactants into the reactor. The first inlet 111 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 100. The first inlet 111 may be configured as a tube, pipe, or have any suitable configuration that is able to transfer reactant(s) into the reactor 100. The first inlet 111 includes an entrance that is connected to a device (e.g., an input assembly) that feeds the first reactant(s) into the first inlet 111. The first inlet 111 includes an exit that is connected to the casing 101, such as the first section 121, to direct the reactant(s) into the first section 102a of the chamber 102.
As shown in
The second inlet 112 is configured to introduce a second reactant, such as air or fuel, into the reactor, such as the first section 102a of the chamber 102 of the reactor 100. The second inlet 112 may be configured to introduce multiple co-reactants into the reactor. The second inlet 112 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. The second inlet 112 may be configured as a tube, pipe, or have any suitable configuration that is able to transfer reactant(s) into the reactor 100. The second inlet 112 includes an entrance that is connected to a device (e.g., an input assembly) that feeds the second reactant(s) into the second inlet. The second inlet 112 includes an exit that is connected to the casing, such as the first section 121, to direct the reactant(s) into the first section 102a of the chamber 102.
As shown in
Therefore, the first and second inlets 111, 112 may be configured as tangential inlets in order to introduce the reactants at tangential locations along the first section 121 of the casing 101. This arrangement may advantageously produce swirl and turbulence in the chamber 102 of the reactor 100, which may help promote the high temperatures that are necessary for carbothermic reduction. The initial turbulence may be further increased in the chamber 102, such as by the throat to further increase the temperatures in the flame zone of the reactor, as discussed in more detail below. Alternatively, the first inlet 111 and/or the second inlet 112 may have first and/or second radial configurations relative to, for example, the longitudinal axis LA.
Also shown in
As shown in
The inlets of the reactors, as disclosed herein, (e.g., the first inlets 111, 211 and/or the second inlets 112, 212) may include a damper or other suitable device configured to regulate or adjustably control the flow rate of the reactants through the inlet(s). Accordingly, the reactor may be configured such that the first inlet introduces the first reactant (e.g., air) into the chamber at a first controlled (and adjustable) flow rate, and the second inlet introduces the second reactant (e.g., fuel) in the chamber at a second controlled (and adjustable) flow rate in order to fuel the reaction within the reactor in a controlled manner. Thus, the inlets may be configured having adjustable pressures to produce adjustable velocities that push the reactants through the inlet and into the combustion chamber.
It is noted that the reactors, as disclosed herein, may include a fewer or greater number of inlets from the reactors 100, 200. For example, the reactor may include a single inlet configured to introduce the reactant(s) into the chamber. Any additional inlets may be configured similar to, the same as, or different than the inlets described herein. For example, the reactors may include secondary inlets positioned downstream of the first section of the chamber, as described below.
The outlets 113, 213 of the reactors 100, 200 may be configured to provide for the removal (e.g., recovery) of a usable product (e.g., CaC2) produced by the reactor, such as during and after combustion of the reactants, from the casing 101, 201. For example, each outlet 113, 213 may include a tap, a valve, or other suitable device that is configured to allow selective removal of the molten slag including the usable product from the reactor. As shown in
The reactors, as disclosed herein, may include a feature (e.g., throat, venturi) to induce a vacuum in the chamber to influence the turbulence and the temperature in the chamber to promote carbothermic reduction of the reactant(s) introduced into the chamber. The throat may be integrally formed with the casing, such as one or more layers of the casing, or may be formed separately then coupled to the casing.
As shown in
The throat 125 may be formed in the intermediate layer 116 and/or the inner layer 115 of refractory material underlying the intermediate layer 116. As shown, the second portion 102b of the chamber 102 has a uniform size (e.g., cross-sectional area, diameter) and, therefore, the size of the throat 125 is the same as the second portion 102b. Thus, the size of the second section 102b of the chamber 102 and the throat 125 may be smaller than the size of the chamber sections that are located upstream and/or downstream of the throat 125.
Alternatively, the section of the reactor defining the throat (e.g., the throat region) may be configured to have a non-uniform size and/or shape, such as having a varying size moving along the respective section of the casing. For example, the throat region may have a tapered shape (e.g., linear taper, curved taper, etc.). As shown in
The narrowing region 224 may be configured adjacent to and extending from the first section 202a of the chamber 202, or there may be one or more additional sections of the chamber provided between the first section 202a and the narrowing region 224. For example, there may be an intermediate section 202d disposed between the first section 202a of the chamber and the narrowing region 224 (e.g., the second section 202b of the chamber 202), which has a size (e.g., cross-section) that is greater than the size of the narrowing region 224, but less than the size of the first section 202a.
The narrowing region 224 may be configured having an angle (e.g., an angle of convergence), which may be measured relative to the longitudinal axis LA of the reactor. As shown in
The inner layer of the casing may include a second portion that extends from the first portion toward the outlet of the reactor. Also shown in
Alternatively, the section downstream of the throat may be configured having a non-uniform shape and/or size. As shown in
The widening region may be configured having an angle (e.g., an angle of divergence) of between 0° and 90°, and preferably is less than 90°. More preferably, the angle is configured to be less than the angle A. According to other examples, the third section 502c may have a non-uniform (e.g., non-linear, curved, etc.) widening arrangement moving from the throat 525 toward the outlet 513. The reactor 500 including the increasing tapered section (e.g., the third section 502c) downstream of the throat 525 may advantageously have a lower pressure drop compared to the reactor including a downstream section having a uniform size, such as the reactors of
The reactor 500 may optionally include additional chamber sections downstream of the third section 502c. Also shown in
According to an exemplary embodiment, the throat is configured as a venturi in order to induce a vacuum, which may draw in (e.g., suck) the reactants and/or other materials, which may be introduced into the reactor, to expose the reactants/materials to the high temperatures in the vacuum. The throat may increase the flow of the reactants (e.g., the velocity of the reactants) through the chamber and may advantageously increase the temperature in the chamber to help provide the relatively high flame temperatures (e.g., 1500-2500° C.), which are necessary for the carbothermic reduction of, for example, calcium oxide (CaO) to CaC2. The tangential injection of reactants into the throat may also promote swirl in the chamber, which may increase the turbulence through the throat upstream of the throat, and/or downstream of the throat. The increased turbulence may advantageously increase the shear forces in the fluid flow, which may tear away any solid materials, such as carbonaceous material (e.g., soot, ash, etc.), slag, minerals, and/or slag, from the inner surface of the reactor. This arrangement may advantageously help keep the inner surface relatively free of buildup of solid materials. The increased turbulence may also advantageously promote mixing and high rates of carbothermic reduction while reactant materials are in-flight before downstream deposition to the walls of the chamber where additional carbothermic reduction is expected to occur.
The throats and/or the narrowing regions (e.g., venturi) may be configured having relatively smooth transitions (e.g., a continuous uninterrupted taper), which may help streamline the velocity through the chamber and avoid circular eddies in the chamber. This arrangement may advantageously help increase the suction of the vacuum, which may, for example, help prevent the surface of the throat and/or narrowing region to remain clean (e.g., free of build-up of solid materials or debris).
The reactors, as disclosed herein, are configured to receive reactants (e.g., air, fuel, etc.) into the first section of the chamber through the inlet(s) of the reactor. A burner produces a flame zone configured to combust the reactants passing through the chamber, such as toward the throat. As the reactants flow through the chamber toward the throat, the throat induces a vacuum to increase the turbulence and increase the combustion temperature of the reactants in the chamber. The vacuum may be initiated upstream of the throat, such as in the narrowing region as shown in the example of
The formation of the slag layer in the chamber downstream from the throat 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 throat of the reactor to promote the formation of the slag layer during operation of the reactor 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, 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 throat of the reactor to accelerate the formation of the product (e.g., CaC2) in the melt as part of the slag layer. The presence of CaC2 in the slag layer, may serve to promote the chemical reaction that forms additional compounds of CaC2. In this case, the input reactant being fed into the reactor may be partially converted reactants from another reactor system or alternatively the injected reactants may be doped with relatively pure CaC2 in order to serve as a catalyst in the formation of CaC2 in the slag layer.
The reactors, as disclosed herein, may include one or more than one secondary inlet, which may be provided upstream and/or downstream of the throat, and/or a temperature regulating device. For example, the reactor may include a single secondary inlet provided upstream of the throat and downstream of the first section of the casing and/or the chamber.
As shown in
Also shown in
Each secondary inlet may be configured to introduce a secondary material (e.g., a second input reactant) into the reactor. For example, each secondary inlet may be configured to introduce a residual oil (e.g., coal tar, aromatic oils from petroleum, biochar created from pyrolysis processes, etc.) into the chamber of the rector. The residual oil may preferably be a low cost, viscous material. For example, the residual oil may be a slurry of oil, finely ground coal particles, and finely ground calcium oxide particles. A calcium source (e.g., calcium oxide, calcium hydroxide, calcium carbonate, etc.) is essential for calcium carbide production. The residual oil may be preheated to promote higher temperatures in the chamber and is introduced to promote formation of the usable product in the chamber by reacting in flight and/or promoting the production of a usably product. For example, the residual oil may be introduced at an downstream location relative to the throat (as shown in
According to an exemplary embodiment, the at least one secondary inlet is configured to introduce a product source, such as a calcium source, and a carbon source as the secondary input reactants. The calcium source may comprise calcium oxide (CaO), calcium carbonate (CaCO3), lime, a combination thereof, or any other suitable material including calcium. The carbon source may comprise coal, coke, a combination thereof, or any other suitable material including carbon. Additionally, the one or more than one secondary input reactant may be configured as a co-reactant. For example, the co-reactant may comprise an oxide, hydroxide, carbonate (e.g., of calcium, lithium, sodium, potassium, magnesium, etc.), or any other suitable element or compound. By introducing the calcium source and the carbon source, the carbothermic reactions in the reactor may produce a usable product, such as CaC2.
It should also be noted that the reactor may be configured to produce other useful 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.
Slag viscosity modifier additives may include low melting feldspar minerals. Feldspars typically melt at temperatures of around 1000° C.˜1200° C. and are the most abundant group of minerals in the earth's crust. Feldspars are alkali containing mineral deposits comprised of individual, or mixed, alkali metal components; typically sodium, potassium, and calcium. Sodium feldspar (albite) has the chemical formula: Na2O.Al2O3.6SiO2. Potassium feldspar (orthoclase) has the chemical formula: K2O.Al2O3.6SiO2. Lime feldspar (anorthite) has the chemical formula: CaO.Al2O3.2SiO2. In addition to serving as fluxing agents to reduce the melting temperature and viscosity of slag melts, these feldspars may also serve as feedstock for the reactor, carbothermically reduced at elevated temperatures in the presence of carbon char, resulting in the formation of desired acetylides: sodium carbide (Na2C2), potassium carbide (K2C2) and calcium carbide (CaC2); all of which readily hydrolyze when contacted with water to form acetylene.
As shown in
The temperature regulating device 440 is configured to reduce the temperatures inside the chamber of the reactor 400. For example, the temperature regulating device 440 may be configured to cool the hot off-gases produced by the reactor. The temperature regulating device may include a water scrubber, a fluid (e.g., water) spray, or another suitable device that can quickly cool the material in the reactor from the high temperatures down to a lower temperature, such as 130° C. Alternatively, the hot off-gases produced by the reactor may be used in a boiler, such as for fuel in the boiler provided downstream of the reactor.
It is noted that although
Now, a calculation of one example for a venturi reactor is provided for the production of CaC2 using coal and CaO. For this calculation, a reactor similar to the embodiment of
For this calculation, it was assumed that 1.75 kg/hr of methane is fed tangentially into the first chamber through a first inlet of the first section and 7.1 kg/hr of O2 is fed through a second inlet in the first chamber where the methane and oxygen combust producing a hot off gas mixture of CO, CO2, H2, water vapor and unreacted O2. A steam jacket around the first chamber is used to remove excess heat and maintain a temperature of 2300° C. The hot off gas travels into the second section.
For this calculation, it was assumed that 32.7 kg/hr of coal and 84 kg/hr of CaO enter the venturi reactor through a common inlet in the second section, where they are mixed and heated with the hot off gas. As the coal is heated, it releases all its volatile matter, including hydrogen, sulfur, oxygen, nitrogen and some of its carbon. The oxygen from the coal, as well as the O2 in the original off gas, and the hydrogen react with the remaining gaseous compounds to produce mainly CO, CO2, H2O, H2S and SO2. As the gas and solid travel into the third section of the reactor, the solid coal particles are softened at these elevated temperatures and impact the walls of the reactor, creating a molten slag layer that slowly flows down the reactor walls toward the exit of the third section. Similarly, the CaO particles, upon hitting the walls of the reactor, are trapped in the molten slag where they flow with the slag and react with the carbon in the slag layer. For this calculation, 75% of the carbon was calculate to react with the CaO, in the manner described above, producing CaC2 solid and CO gas. The exiting slag flow rate is 29.8 kg/hr, with 25.0 kg/hr of CaC2 (83.9% purity). Because of the endothermic reaction, the exiting slag layer and off gas are at 1800° C. By the time the off gas exits the third section of the reactor, all the O2 has fully reacted and the final gas composition (at thermodynamic equilibrium) is:
The off gas travels to a downstream reactor where air or O2 is introduced to allow combustion to go to completion and heat is extracted from the gas stream, for example to produce high pressure steam for power generation.
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 are 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, such as the casings of the reactors, 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. For example, any element (e.g., inlet, burner, casing, etc.) disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein.
This application claims the benefit of and priority to U.S. Provisional Patent App. No. 61/821,992, which was filed on May 10, 2013. The foregoing U.S. provisional application is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61821992 | May 2013 | US |