Process for production of H.SUB.2 .rich synthesis gas from coal/steam with Cu—Fe-alumina based catalysts
12122967 · 2024-10-22
Assignee
Inventors
Cpc classification
C10J3/16
CHEMISTRY; METALLURGY
International classification
Abstract
Materials, methods to prepare, and methods of use for producing an H.sub.2 rich synthesis gas stream from coal free of nitrogen is described. One embodiment of the method comprises. The method includes an oxygen carrier at least partially reduced using a fuel in a reactor forming a reduced metal oxide comprised of first series3d block-transition metals or mixture thereof. The reduced metal oxide is reacted with the solid fuel/steam to produce H.sub.2 and CO.sub.2/CO in the reactor; and the reduced metal oxide is added separately or simultaneously with a solid fuel while not impregnating the solid fuel with the reduced metal oxide.
Claims
1. A method for producing a syngas from a reduced metal aluminate catalyst, a steam, and a solid fuel consisting of: reducing the metal aluminate catalyst selected from one or more transition metal aluminates using the solid fuel for producing the reduced metal aluminate catalyst, wherein the one or more transition metal aluminates is selected from the group consisting of Cu.sup.+1, Cu.sup.0, and Fe.sup.+2, continuously delivering the steam and the solid fuel to the reduced metal aluminate catalyst; and supplying a heat for producing a continuous stream of syngas, wherein the syngas comprises a product stream consisting of at least >than 50 vol % of H.sub.2 and CO, wherein the solid fuel consisting of a solid carbonaceous fuel selected from the group consisting of a coal, coke, char biomass and biofuel, and wherein a reaction temperature for producing the syngas from the reduced metal aluminate catalyst, the stream and the solid fuel are greater than 500 C.
2. The method of claim 1, wherein supplying the heat is by a combustion of at least one or more of a fuel, a chemical looping combustion, a microwave heating source and a solar energy.
3. The method of claim 1, further comprising a reactor, wherein the reactor comprises a fluidized bed, a fixed bed, a moving bed or a spouted bed.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) These and other features, aspects, and advantages of the multiple embodiments of the present invention will become better understood with reference to the following description, appended claims, and accompanied drawings where:
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DESCRIPTION OF THE EMBODIMENTS
(14) The following description is provided to enable any person skilled in the art to use the embodiments of the invention and sets forth the best mode contemplated by the inventor for carrying out the invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the principles of one or more embodiments of the invention are defined herein specifically to provide description of ionic inorganic materials, methods of their preparation, and methods for using such materials. One or more embodiments relate to producing a H.sub.2 rich synthesis gas stream free of nitrogen from coal. More specifically, one or more embodiments relate to a catalytic process combined with or without chemical looping combustion to produce a H.sub.2 rich synthesis gas stream free of nitrogen from coal.
(15) One or more embodiments relates to a method for producing a syngas from a reduced metal oxide/oxygen carrier, steam and solid fuel combined with heat from a chemical looping combustion. The method includes reducing the metal oxide/oxygen carrier forming the reduced metal oxide/oxygen carrier, wherein the reduced metal oxide/oxygen carrier is selected from a transition metal oxide or a mixture there of with a gaseous or solid fuel in the fuel reactor; transferring some portion of the reduced metal oxide from fuel reactor to a catalytic reactor; supplying steam and solid fuel to the catalytic reactor containing the reduced metal oxide to produce H.sub.2 rich syngas, wherein the reduced metal oxide catalyst enhances the H.sub.2 rich syngas production rate with coal and steam; transferring some portion the reduced carrier from the fuel reactor to an oxidizing reactor; supplying the oxidizing gas to the oxidizing reactor, thereby generating heat and a re-oxidized oxygen carrier; transferring heat from the oxidizing reactor to the catalytic reactor; and transferring the re-oxidized oxygen carrier from oxidizing reactor to the fuel reactor.
(16) Yet another embodiment relates to a method for producing a syngas from reduced metal aluminate catalyst, steam, solid fuel. The method includes reducing the metal aluminate catalyst selected from one or more transition metal aluminates or a mixture of transition metal aluminates using at least one of a gaseous and solid fuel, producing a reduced metal aluminate catalyst; continuously delivering steam and solid fuel to the reduced metal aluminate catalyst; and supplying heat, producing a continuous stream of H.sub.2 rich syngas.
(17) Yet another embodiment relates to a method of producing a synthesis gas rich in hydrogen from solid carbonaceous fuel. The method includes delivering a metal aluminate to a reactor, where the metal aluminate is selected from the group comprising iron aluminate, copper-iron-manganese aluminate and copper-iron-aluminate; partially or fully reducing the metal aluminate with a solid or gaseous fuel; delivering a solid fuel to the reactor; delivering steam to the reactor; converting some portion of the solid fuel and the steam to a hydrogen rich synthesis gas and maintaining the reactor above 500 C.; continuing the delivery of steam and solid fuel to the reactor; and withdrawing product stream from the reactor, where the gaseous product comprises product stream, and where at least >50 vol. % of the product stream consists of H.sub.2 and CO.
(18) One or more methods of the present invention may include the reduced metal aluminate is selected from the group comprising Cu.sup.+1, Cu.sup.0, Fe.sup.0 and, Fe.sup.+2. The heat may be supplied by combustion of at least one or more of a fuel, chemical looping combustion, a microwave heating source and solar energy. The fuel comprises a solid carbonaceous fuel selected from the group comprising coal, coke, char. biomass and biofuels.
(19) Still other applications may include the reactor comprises a fluidized bed, fixed bed, moving bed or spouted bed; and the reaction temperature of reduced metal aluminate, coal and steam is greater than 500 C. In one or more embodiments the H.sub.2 rich syngas product stream is at least >50% vol. of H.sub.2 and CO.
(20) Embodiments relate to a catalytic process to produce H.sub.2 rich syngas directly from coal/steam as shown in
(21) Embodiments of the current process 10 have been demonstrated in a fluidized bed reactor where the contacts between the reduced metal oxide and coal is minimal during the H.sub.2 production process. The reduced oxygen carrier which does not get oxidized during the process may be used continuously for H.sub.2 rich syngas production as a catalytic process. Hence this process has a major advantage over H.sub.2 production process from steam decomposition with reduced metal which is operated in a cyclic manner because the metal gets oxidized and it has to be reduced prior to the next cycle.
(22) Also, unlike the H.sub.2 production from water splitting process with reduced iron oxide, one of the major advantages of the process is that it does not require an air separation unit for production of nitrogen free synthesis gas for initial reduction. The reduced oxygen carrier does not have to be in contact with the coal. The preferable temperatures for the catalytic process in the reactor 16 of
(23) Steam is required for the coal/steam/reduced oxygen carrier and the heat to produce steam may be obtained from the CLC of the same oxygen carrier. Embodiments of the invention relate to a process 100 with a three-reactor system (102, 104 and 106) shown in
(24) The oxidation reaction in reactor C 106 is exothermic and the heat 120 generated from the reactor C 106 may be used for production of steam that is required in the catalytic reactor B 102. The reduced oxygen carrier 114 from reactor A 104 is transferred to the catalytic reactor 102 in which coal/steam c is continuously added to produce H.sub.2 (major) and CO.sub.2/CO 126. Other carbonaceous fuels such as coke, bio mass and like may also be used instead of coal. The temperature in the reducing reactor A 104 is sufficient to reduce some portion of the metal oxide oxygen carrier while the temperature of the oxidizing reactor C 106 is sufficient to oxidize some portion of reduced metal oxide. In the catalytic reactor B 102, the reduced oxygen carrier remains reduced while coal-steam via the catalytic process produces syngas containing a high H.sub.2 concentration. The reduced oxygen carrier does not have to be in contact with the coal. The preferable temperatures for the catalytic process in the reactor B 102 is greater than 500 C.
(25) The oxygen carrier may comprise 3d block-transition (T) metal oxide or mixed metal oxides such as T.sub.xO.sub.yZ.sub.pO.sub.q where Z is a single or mixed metal oxides selected from transition metals, alkali or alkali earth metals or Ce, Zr, V, Mo, Sn and x>0, y>0, p>0, q>0. In addition, an inert support may also be used. The oxygen carrier (metal oxide) may be fully or partially reduced for catalytic production of H.sub.2 (high) and CO.sub.2/CO with coal/steam. For example, reduced iron oxide component may contain Fe metal or an iron oxide such as FeO, Fe.sub.3O.sub.4 and reduced copper oxide may contain Cu.sup.+1 or Cu.sup.0.
(26) The syngas stream with high H.sub.2 concentration produced by coal/steam/reduced metal oxide may be further processed in a commercial water gas shift reactor followed by a CO.sub.2 separation unit such as pressure swing process to obtain pure hydrogen.
(27) Oxygen carriers CuOFe.sub.2O.sub.3-alumina, hematite from Cliffs Natural Resources, Canada, and AMIRON-OH 48 hematite from Applied Minerals, N.Y. were used in this study. The oxygen carrier, CuOFe.sub.2O.sub.3-alumina was prepared using the commercial spray drying method at Nexceris Inc. and this oxygen carrier has shown promising results for chemical looping combustion. See e.g. Siriwardane et al., Fluidized bed testing of commercially prepared MgO-promoted hematite and CuOFe.sub.2O.sub.3 mixed metal oxide oxygen carriers for methane and coal chemical looping combustion, Applied Energy, 157 (2015) 348-357, 2015. The composition of the oxygen carrier was 30 wt. % CuO, 30 wt. % Fe.sub.2O.sub.3, and 40 wt. % alumina, and the particle size range was 74-250 m. Natural mineral hematite had a particle size of 300-600 m.
(28) Coals used in the experiments were Illinois #6 (High volatile bituminous coal), Rosebud coal (Sub bituminous coal) and Wyodak coal (Sub bituminous coal).
(29) The temperature programmed reaction (TPR) studies were carried out using a fluidized bed reactor manufactured by Autoclave Engineers HR-160 Reactor Assembly (Model #5010-2377/HR-160). The oxygen carrier/coal bed height was 7.62 cm, and the diameter was 6 cm. The reactor column was made from Inconel SB-564 to withstand temperatures up to 900 C. A ceramic porous plate with 15-40 m pores was used as the gas distributor. The setup is equipped with three electrical heaters installed around the reactor to heat the reactor to the target temperature of 850 C. Prior to the tests, either 20 g each of coal and 322 g CuOFe.sub.2O.sub.3-alumina oxygen carriers were mixed. Then the mixture was heated from 25 C. to 850 C. at a heating rate of 4 C./min in helium at a flow rate of 7.8 SLPM (24MFV of FeCu/alumina at 850 C.).
(30) Then the sample was maintained at 850 C. for 0.5 hours in helium. During the experiments, 15-30 vol. % steam was introduced either during the temperature ramp beginning at 300 C. or after the isothermal dwell at 850 C. After the reduction of the oxygen carrier with coal, the sample was cooled to ambient in He and additional 10 g of coal was added to the already reduced oxygen carrier. The 10 g coal addition TPR cyclic process was continued until 50-60 g of coal was consumed. The reactor effluent was monitored using a Pfeiffer Omnistar mass spectrometer. For the tests with Applied Minerals hematite the flow rate was 7.8 SLPM and for Cliffs hematite it was 11.6 SLPM. The amounts of Cliffs and Applied Minerals hematite used in the Fluidized bed tests were 545 g and 322 g respectively.
(31) In some experiments, initial oxygen carrier reduction was conducted using. H.sub.2 for the first part of the experiment the reactor was loaded with oxygen carrier, and heated from ambient temperature to 700 C. in Helium. At 700 C., 10% H.sub.2 in He was introduced until the oxygen carrier was completely reduced. After the reduction with H.sub.2, reactor was cooled to ambient temperature in He and 10 g of coal was added. Then the coal/reduced oxygen carrier was heated to 850 C. and kept isothermal for 30 mins. and 15% steam was added. Two blank experiments were conducted: First test by reducing the oxygen carrier at 700 C. with 10% H.sub.2/He, then heating up the reduced oxygen carrier to 850 C. (no coal addition) and introducing 15% steam at 850 C. and the second blank test by heating coal to 850 C. (no oxygen carrier) and introducing steam at 850 C.
(32) In some experiments, initial reduction was conducted with methane and after the reduction with methane the oxygen carrier was cooled to ambient temperature, mixed with coal and temperature ramp was conducted with steam/helium.
(33) Fluidized bed reactor test data of CuOFe.sub.2O.sub.3-Alumina oxygen carrier (MO) with Wyodak coal/steam to produce H.sub.2 rich syngas during temperature ramp from ambient to 850 C. with 30% steam addition at 300 C. are illustrated in
(34) Comparative plots of data during similar temperature ramps with I0 g of Wyodak coal/30% steam without an oxygen carrier and 10 g Wyodak coal/unreduced oxygen carrier/30% steam are shown in
(35) Tests were conducted to understand whether the process of H.sub.2 production is continuous with the reduced oxygen carrier when the coal addition was continued after the initial reduction. In this test series, 15% steam was added at 850 C. after the temperature ramp with coal/oxygen carrier. The results are shown in
(36) TPR tests with Rosebud coal which is a sub bituminous coal was also conducted with CuOFe.sub.2O.sub.3Al.sub.2O.sub.3 oxygen carrier in the fluidized bed reactor. TPR-cycle 1 was performed with 20 g of coal and the oxygen carrier, with 15% steam addition at 300-850 C. Then three cycles of TPR were conducted by cooling the oxygen carrier and adding 10 g coal in each cycle. Blank experiment was also conducted with coal/steam without the oxygen carrier. The concentrations and amounts of gases produced are shown in
(37) TPR was also performed with Illinois #6 coal which is a high rank bituminous coal and CuOFe.sub.2O.sub.3Al.sub.2O.sub.3 oxygen carrier in the fluidized bed reactor. Similar to the previous tests, TPR was performed with 20 g of coal in cycle 1 with 15% steam addition at 850 C. and TPR cycles were repeated with a new 10 g coal/steam sample for three more cycles. Blank experiment was also conducted with Illinois #6 coal/steam without the oxygen carrier. The concentrations and amounts of gases produced are shown in
(38) To understand the effect of extent of reduction on H.sub.2 production with coal/steam, the CuOFe.sub.2O.sub.3-alumina oxygen carrier was fully reduced with 10% H.sub.2 in He at 700 C. Then the reduced oxygen carrier was cooled to ambient temperature, 10 g of coal was added and temperature ramp was performed up to 850 C. with 15% steam addition at 850 C. The results are shown in
(39) X-ray diffraction studies (XRD) were conducted to identify the phases of CuOFe.sub.2O.sub.3 Alumina oxygen carrier formed after the multi-cycle reactions with coal/steam. The XRD data of fresh and reacted with a metal aluminate catalyst such as CuOFe.sub.2O.sub.3-Alumina with both Wyodak and Illinois #6 coal is shown in Table 1. It should be noted that some Cu metal and Fe metal were detected with the reacted samples. The data indicated that metallic iron and copper remained after multi-cycle reaction with coal/steam.
(40) TABLE-US-00001 TABLE 1 XRD data of fresh and reacted metal aluminate catalyst such as CuO-Fe.sub.2O.sub.3-Alumina Reacted with Reacted with Wyodak Illinois #6 Phases Fresh coal/steam coal/steam Spinel (Cu aluminate) 40 31 20 Corundum (aluminum oxide) 13 11 23 Hercynite (iron aluminate) 47 33 42 Fe 12 13 Cu 13 2
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(42) X-Ray photoelectron spectroscopy (XPS) which is a surface analysis (50 A of the surface) technique was conducted to determine the elemental and oxidation changes of CuOFe.sub.2O.sub.3-Alumina after reactions with coal/steam. XPS data of the fresh material showed the presence of Cu.sup.+.sup.
(43) TPR experiments in the Fluidized bed reactor was also performed with natural mineral hematite (Fe.sub.2O.sub.3). TPR was performed with 20 g of Wyodak coal/Applied minerals hematite in cycle 1 with 15% steam addition at 850 C. and TPR cycles were repeated with anew 10 g coal sample/steam at each cycle for five more cycles. Blank experiment was also conducted with coal/steam without the oxygen carrier. The concentrations of gases produced are shown in
(44) H.sub.2 was used as the fuel for the initial reduction with Cliffs natural mineral hematite and then Wyodak/coal/steam TPR was conducted to determine the H.sub.2 production. Hematite was fully reduced with 10% H.sub.2 in He at 700 C. Then the reduced oxygen carrier was cooled to ambient temperature, 10 g of coal was added and temperature ramp was performed up to 850 C. with 15% steam addition at 850 C. The results are shown in
(45) Methane was used for the initial reduction step with Cliffs natural mineral hematite. Reduction time was changed to obtain different extents of reduction. The data with reduced hematite/coal/steam are shown in
(46) The process described herein differs from the catalytic coal gasification process reported in the literature in which coal is impregnated with solutions containing the catalysts such as alkali and iron salts. The process described herein was conducted in a fluidized bed reactor and the contact between the reduced metal oxide and coal was minimal. Coal may be added to the reactor continuously which makes the operation very easy unlike the catalytic gasification in which the coal must be impregnated with catalyst solution.
(47) These data also indicated that the H.sub.2 rich syngas production process herein with coal/steam/reduced oxygen carrier could not have been proceeded via WGS shift reaction. When coal/steam was introduced to the reduced oxygen carrier, rates of production of H.sub.2, CO.sub.2 and CO increased simultaneously (
(48) Therefore, the likely mechanism for enhanced H.sub.2 production with reduced oxygen carrier by coal/steam is due to enhancement of reaction [3] which also contributes to 2 moles of H.sub.2 for every CO.sub.2 mole. When steam concentration was 30 vol. % there was more CO.sub.2 than that with 15 vol. %. With more steam, reaction [3] appears to be the dominant reaction.
(49) It is possible that, the sulfur released from coal may react with the reduced oxygen carrier and sulfur may be removed as SO.sub.2 by oxidizing the oxygen carrier and the SO.sub.2 stream may be processed using traditional SO.sub.2 removal processes or may be used for CaSO.sub.4 production. Ash generated in the process will be mixed with the reduced metal oxide and ash may be removed by density separation or magnetic separation.
(50) Embodiments relate to a method for producing an H.sub.2 stream free of nitrogen from coal, the method comprising an oxygen carrier at least partially reduced using a fuel in a reactor forming a reduced metal oxide comprised of first series3d block-transition metals or mixture thereof. The reduced metal oxide is reacted with the solid fuel/steam to produce H.sub.2 and CO.sub.2/CO in the reactor; and the reduced metal oxide is added separately or simultaneously with a solid fuel while not impregnating the solid fuel with the reduced metal oxide.
(51) Embodiments may include the metal oxide comprises the first series3d block-transition metal (T) oxide or mixed metal oxides such as T.sub.xO.sub.yZ.sub.pO.sub.q or Z.sub.pT.sub.xO.sub.y where Z is a single or mixed metal oxide selected from transition metals, alkali, alkali earth metals or Ce, Zr, V, Mo, Sn and x>0, y>0, P>0, Q>0; the metal oxide comprises a hematite or CuOFe.sub.2O.sub.3 mixture which may be reduced to Cu.sup.+1, Cu.sup.0, Fe.sup.0, Fe.sup.+2, Fe+.sup.3; and/or the reduced metal oxide comprises reduced forms of transition metal oxides, alkali metal oxides and Ce, Zr, V, Mo, Sn.
(52) Embodiments includes an inert support may be combined with the metal oxide, wherein the inert support comprises from about 5 wt. % to about 60 wt. % of the metal oxide and the inert support may comprise alumina, silica, alumina silicates, clay, titania, or mixtures thereof. The inert support may interact to form compounds with metal oxides forming aluminates, silicates, titanates of transition metals such as iron aluminates and copper aluminates.
(53) Embodiments may include the solid fuel comprises coal, coke, char.biomass or bio fuel; or the fuel used for the initial reduction of the metal oxide comprises methane, hydrogen, syngas, coal, coke, char, bio mass, or biofuel.
(54) One or more embodiments include the H.sub.2 rich syngas product stream is at least >50% vol. of H.sub.2 and CO. The reactor may comprise a fluidized bed, fixed bed, moving bed or spout bed. The reaction temperature of the reduced metal, coal and steam is greater than 500 C. Further the steam required for the process is generated from heat from a chemical looping combustion of fuel with metal oxide.
(55) Still other embodiments relate to a method for producing syngas from reduced metal oxide/steam/solid fuel combined with heat from a chemical looping combustion of metal oxide wherein the process comprises reducing the metal oxide or oxygen carrier selected from a transition metal oxides or a mixture there of with a gaseous or solid fuel in the fuel reactor; transferring some portion of the reduced metal oxide from a fuel reactor to a catalytic reactor; supplying steam and solid fuel to the catalytic reactor containing the reduced metal oxide to produce H.sub.2 rich syngas; transferring some portion the reduced carrier from the fuel reactor to an oxidizing reactor; supplying the oxidizing gas to the oxidizing reactor, thereby generating heat and a re-oxidized oxygen carrier; transferring heat from the oxidizing reactor to the catalytic reactor; and transferring the re-oxidized oxygen carrier from oxidizing reactor to the fuel reactor.
(56) Yet another embodiment relates to a method of producing synthesis gas rich of hydrogen from sold carbonaceous fuel comprising delivering a metal oxide to a reactor, where the metal oxide comprises iron oxide, CuOFe.sub.2O.sub.3, CuOFe.sub.2O.sub.3-Alumina or thereof>5 wt. %; partially or fully reducing the metal oxide with a solid or gaseous fuel; delivering a solid fuel to the reactor; delivering steam to the reactor; converting some portion of the solid fuel and the steam to a hydrogen rich synthesis gas and maintaining the reactor above 500 C.; continuing the delivery of steam and solid fuel to the reactor; and withdrawing product stream from the reactor, where the gaseous product comprises product stream, and where at least >50 vol. % of the product stream consists of H.sub.2 and CO.
(57) Having described the basic concept of the embodiments, it will be apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations and various improvements of the subject matter described and claimed are considered to be within the scope of the spirited embodiments as recited in the appended claims. Additionally, the recited order of the elements or sequences, or the use of numbers, letters or other designations therefor, is not intended to limit the claimed processes to any order except as may be specified. All ranges disclosed herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof. Any listed range is easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as up to, at least, greater than, less than, and the like refer to ranges which are subsequently broken down into sub-ranges as discussed above. As utilized herein, the terms about, substantially, and other similar terms are intended to have a broad meaning in conjunction with the common and accepted usage by those having ordinary skill in the art to which the subject matter of this disclosure pertains. As utilized herein, the term approximately equal to shall carry the meaning of being within 15, 10, 5, 4, 3, 2, or 1 percent of the subject measurement, item, unit, or concentration, with preference given to the percent variance. 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 exact numerical ranges provided. Accordingly, the embodiments are limited only by the following claims and equivalents thereto. All publications and patent documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication or patent document were so individually denoted.