CN115650167B - Oxygen carrier for preparing synthetic gas by methane chemical chain reforming and preparation method and application thereof - Google Patents
Oxygen carrier for preparing synthetic gas by methane chemical chain reforming and preparation method and application thereof Download PDFInfo
- Publication number
- CN115650167B CN115650167B CN202211106977.2A CN202211106977A CN115650167B CN 115650167 B CN115650167 B CN 115650167B CN 202211106977 A CN202211106977 A CN 202211106977A CN 115650167 B CN115650167 B CN 115650167B
- Authority
- CN
- China
- Prior art keywords
- oxygen carrier
- methane
- gas
- oxygen
- reforming
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 161
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 155
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 148
- 239000001301 oxygen Substances 0.000 title claims abstract description 148
- 239000007789 gas Substances 0.000 title claims abstract description 77
- 239000000126 substance Substances 0.000 title claims abstract description 31
- 238000002407 reforming Methods 0.000 title claims abstract description 25
- 238000002360 preparation method Methods 0.000 title abstract description 16
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims abstract description 75
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 39
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000002243 precursor Substances 0.000 claims abstract description 35
- 238000001354 calcination Methods 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 19
- 238000001035 drying Methods 0.000 claims abstract description 14
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 14
- 238000003756 stirring Methods 0.000 claims abstract description 14
- 238000000227 grinding Methods 0.000 claims abstract description 12
- 229910052742 iron Inorganic materials 0.000 claims abstract description 10
- 229910052727 yttrium Inorganic materials 0.000 claims abstract description 9
- 239000008367 deionised water Substances 0.000 claims abstract description 8
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 40
- 239000011261 inert gas Substances 0.000 claims description 24
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 21
- 239000001569 carbon dioxide Substances 0.000 claims description 19
- 230000001590 oxidative effect Effects 0.000 claims description 14
- 239000000446 fuel Substances 0.000 claims description 12
- 229910017771 LaFeO Inorganic materials 0.000 claims description 11
- 230000008929 regeneration Effects 0.000 claims description 10
- 238000011069 regeneration method Methods 0.000 claims description 10
- 150000002500 ions Chemical class 0.000 claims description 8
- 229910002554 Fe(NO3)3·9H2O Inorganic materials 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 abstract description 50
- 230000000694 effects Effects 0.000 abstract description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 9
- 229910052799 carbon Inorganic materials 0.000 abstract description 9
- 230000008569 process Effects 0.000 abstract description 8
- 230000008021 deposition Effects 0.000 abstract description 7
- 239000000969 carrier Substances 0.000 description 17
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 229910001868 water Inorganic materials 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 11
- 230000009467 reduction Effects 0.000 description 11
- 239000000084 colloidal system Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 230000009257 reactivity Effects 0.000 description 8
- 238000005303 weighing Methods 0.000 description 8
- 239000002737 fuel gas Substances 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 229910044991 metal oxide Inorganic materials 0.000 description 6
- 150000004706 metal oxides Chemical class 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 5
- 235000011114 ammonium hydroxide Nutrition 0.000 description 5
- 150000001768 cations Chemical class 0.000 description 5
- 239000002131 composite material Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 230000035484 reaction time Effects 0.000 description 5
- 238000006057 reforming reaction Methods 0.000 description 5
- 230000001105 regulatory effect Effects 0.000 description 5
- 229910002422 La(NO3)3·6H2O Inorganic materials 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000003825 pressing Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 239000005431 greenhouse gas Substances 0.000 description 3
- 238000000634 powder X-ray diffraction Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000012692 Fe precursor Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000033116 oxidation-reduction process Effects 0.000 description 2
- 238000010926 purge Methods 0.000 description 2
- 238000011946 reduction process Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003090 exacerbative effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000007363 regulatory process Effects 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 229910000314 transition metal oxide Inorganic materials 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Abstract
The invention discloses an oxygen carrier for preparing synthesis gas by methane chemical chain reforming, and a preparation method and application thereof, wherein the oxygen carrier is prepared by the following steps: dissolving precursors of La, Y and Fe in deionized water according to Y xLa1‑xFeO3 to form a precursor solution; wherein x is more than 0 and less than 1; adding citric acid into the precursor solution, stirring until the citric acid is dissolved, adjusting the pH to 7-8, stirring under heating until the citric acid is sticky, drying, grinding and calcining to obtain the oxygen carrier for preparing the synthesis gas by reforming the methane chemical chain. The oxygen carrier is used in the chemical chain reforming process of methane, can effectively improve the reaction activity of the oxygen carrier and methane, has the methane conversion rate of over 92 percent, the synthetic gas selectivity of over 90 percent, and simultaneously has excellent carbon deposition resistance.
Description
Technical Field
The invention relates to the field of synthesis gas production by methane chemical chain reforming, in particular to an oxygen carrier for synthesis gas production by methane chemical chain reforming, a preparation method and application thereof.
Background
Since the industrial revolution, the dependence of human activities on fossil energy has led to an annual increase in the content of greenhouse gases in the atmosphere, represented by CO 2, exacerbating global warming, ocean acidification, sea level rise and the formation of bad weather, greatly threatening the human living environment. Methane is the main component of coal bed gas, shale gas, combustible ice and biological methane, and is the second largest greenhouse gas discharged by the current human activities, and is inferior to carbon dioxide, but the unit greenhouse effect of methane is more than 20 times of that of carbon dioxide.
Methane dry gas reforming (CH 4+CO2→2CO+2H2,ΔH0 298K =247 kJ/mol) can convert methane and carbon dioxide into industrially important synthetic gas, but the reaction is strong in heat absorption and high in energy consumption, and carbon deposition is easy to form and cover an active site to cause catalyst deactivation; in addition, the hydrogen-carbon ratio of the generated synthesis gas is about 1, and if the subsequent methanol synthesis or Fischer-Tropsch synthesis (the required H 2/CO ratio is 2) is carried out, a gas regulating process is added, so that the energy consumption is increased. Methane chemical chain reforming technology utilizes the circulation of an oxygen carrier (usually metal oxide, MO) between a fuel reactor and a regeneration reactor to decouple the gas-gas reaction into two gas-solid half reactions (CH 4+ MO＝2H2+CO,CO2 +m=mo+co), which can not only produce a synthesis gas with a H 2/CO ratio of 2, directly serve as a feed gas for subsequent methanol synthesis or fischer-tropsch synthesis, but also convert greenhouse gases into CO, and can also obtain high purity hydrogen free of carbon contamination if CO 2 is replaced with H 2O(H2O +M＝MO+H2. The key to the successful operation of methane chemical chain reforming technology is the development of oxygen carriers that are resistant to high temperatures and that perform well.
Currently, studies on chemical chain oxygen carriers mainly include transition metal oxide oxygen carriers and composite metal oxide oxygen carriers. The iron-based oxygen carrier has the advantages of low cost, easy availability, environmental friendliness, high oxygen carrying capacity, good reactivity with CO 2 or water vapor and the like, and is considered as one of ideal oxygen carrier materials.
Dai et al [ J.Phys.chem.B,2006,110,45,22525-22531] studied three iron-based perovskite oxides AFeO 3 (A=La, nd, eu) for partial oxidation of methane chemical chains to make synthesis gas, and found that LaFeO 3 exhibited the best synthesis gas yield due to high oxygen mobility. But the reactivity of pure LaFeO 3 oxygen carrier with methane is not high (methane conversion is about 60-70%), and the cycle stability is poor.
At present, the methane chemical chain reforming technology is applicable to Fe-based perovskite oxygen carriers, and the problems of low methane conversion rate, poor cycle stability and the like still exist.
Disclosure of Invention
In order to solve the problems of low reactivity and poor cycle stability of Fe-based perovskite oxygen carriers and methane in the prior art, the invention aims to provide an oxygen carrier for preparing synthesis gas by reforming a methane chemical chain, and a preparation method and application thereof.
In order to achieve the above purpose, the invention adopts the following technical scheme:
An oxygen carrier for preparing synthetic gas by chemical chain reforming of methane has perovskite structure and structural formula Y xLa1-xFeO3, wherein x is more than 0 and less than 1.
Further, x is 0.05.ltoreq.x.ltoreq.0.2.
Further, x is 0.05, 0.1, 0.2, 0.4, 0.6 or 0.8.
A method for preparing an oxygen carrier for preparing synthesis gas by methane chemical-looping reforming, which comprises the following steps:
Dissolving precursors of La, Y and Fe in deionized water according to Y xLa1-xFeO3 to form a precursor solution; wherein x is more than 0 and less than 1;
Adding citric acid into the precursor solution, stirring until the citric acid is dissolved, adjusting the pH to 7-8, stirring under heating until the citric acid is sticky, drying, grinding and calcining to obtain the oxygen carrier for preparing the synthesis gas by reforming the methane chemical chain.
Further, the precursor of La is La (at least one of NO 3)3·6H2 O and H 14ClLaO7), the precursor of Y is Y (at least one of NO 3)3·6H2 O and YCl 3), and the precursor of Fe is at least one of FeCl 3、Fe(NO3)3·9H2 O and FeSO 4.
Further, the total concentration of the precursors of La, Y and Fe in the precursor solution is 1-1.2 mol/L.
Further, the amount of citric acid is 1.5 to 2.5 times the total molar amount of La, Y and Fe.
Further, the calcination process is as follows: calcining at 300-500 deg.c for 2-5 hr and then at 800-1000 deg.c for 2-5 hr.
Use of an oxygen carrier as described above for the chemical looping reforming of methane to produce synthesis gas, characterized in that the oxygen carrier is circulated between two communicating fuel reactors and a regeneration reactor; wherein, in the fuel reactor, the oxygen carrier oxidizes methane at 800-1000 ℃ to produce synthesis gas; in the regeneration reactor, the oxygen carrier is oxidized and regenerated at 800-1000 ℃ under an oxidizing atmosphere, and then enters the fuel reactor.
Further, the fuel reactor is a mixed gas of methane and inert gas, and the oxidizing atmosphere is a mixed gas of carbon dioxide and inert gas, a mixed gas of water vapor and inert gas, a mixed gas of oxygen and inert gas or a mixed gas of water vapor and carbon dioxide.
Further, the volume fraction of methane in the mixed gas of methane and inert gas is 2% -100%, the volume fraction of carbon dioxide in the mixed gas of carbon dioxide and inert gas is 2% -100%, the volume fraction of water vapor in the mixed gas of water vapor and inert gas is 2% -100%, and the volume fraction of oxygen in the mixed gas of oxygen and inert gas is 2% -100%.
Compared with the prior art, the invention has the beneficial effects that:
The composite metal oxide Y xLa1-xFeO3 (x= 0,0.05,0.1,0.2,0.4,0.6 and 0.8) series oxygen carrier with perovskite structure is prepared by the invention, the doping of Y does not form a hetero-phase, the Y 3+ ion with smaller radius successfully replaces part of La 3+ ion, the grain size of the oxygen carrier is effectively reduced, the dispersibility and the transmission and diffusion capacity of lattice oxygen are improved, and the perovskite structure is maintained in the multiple circulation process, so that the prepared oxygen carrier has high temperature resistance, strong sintering resistance and stable mechanical property in the circulation process.
The composite metal oxide Y xLa1-xFeO3 (x= 0.05,0.1,0.2,0.4,0.6 and 0.8) series oxygen carrier with perovskite structure has excellent methane activating ability and cycle stability. In the methane reduction process, fe species in the oxygen carrier doped with Y undergo deep reduction, zero-valent iron is generated on the surface of the oxygen carrier, and the oxygen carrier has the functions of efficiently adsorbing and activating methane. The reaction activity of the oxygen carrier and methane is greatly improved after the Y doping, but no carbon deposition is found, which indicates that the oxygen supply of the oxygen carrier is sufficient in the reaction process, and the Y doping greatly improves the transmission and diffusion capacity of lattice oxygen in the bulk phase, so that the lattice oxygen is continuously transported from the bulk phase to the surface for oxidizing the activated methane and partially oxidizing the methane into the synthesis gas with high selectivity. In addition, the doping of Y also obviously improves the dispersibility of the active component, inhibits the agglomeration and sintering of oxygen carrier particles in the reaction process, and further improves the circulation stability. When x=0.1, the Y 0.1La0.9FeO3 oxygen carrier has the optimal methane reaction activity, the methane conversion rate and the synthesis gas selectivity can still reach more than 90% by 30 th circulation, the molar ratio of H 2 to CO is maintained between 1.9 and 2.1, the ideal value is close to 2, and the quality of the synthesis gas is higher. The oxygen carrier has outstanding methane reaction activity, synthesis gas selectivity, carbon deposition resistance and cycle stability.
The Y xLa1-xFeO3 composite metal oxide with perovskite structure in the invention has universality to oxidizing atmosphere, can realize oxidation regeneration in air, water, carbon dioxide or water/carbon dioxide mixture, and has excellent cycle stability. The preparation method of the oxygen carrier is simple, environment-friendly and easy for industrial production.
Drawings
FIG. 1 is an X-ray powder diffraction pattern of the fresh state of the oxygen carrier prepared in comparative example 1 and examples 1, 2, 3.
FIG. 2 is a graph showing the kinetics of the oxygen carrier prepared in comparative example 1 during the reaction.
FIG. 3 is a graph of the kinetics of an oxygen carrier prepared in example 1 during a reaction.
FIG. 4 is a graph of the kinetics of an oxygen carrier prepared in example 5 during a reaction.
FIG. 5 is a graph comparing CH 4 conversion and H 2/CO over 10 cycles of reaction for the oxygen carriers prepared in comparative example 1, example 2, and example 4.
FIG. 6 is a graph comparing the synthesis gas yield and oxygen evolution during 10 cycles of the reaction for the oxygen carriers prepared in comparative example 1, example 2 and example 4.
FIG. 7 is an X-ray powder diffraction pattern of the oxygen carrier prepared in comparative example 1 after 2 reduction cycles, 10 reduction cycles and 10 reduction cycles, respectively.
FIG. 8 is an X-ray powder diffraction pattern of the oxygen carrier prepared in example 2 after 2 reduction cycles, 10 reduction cycles and 10 reduction cycles, respectively.
FIG. 9 is a graph of conversion, selectivity and H 2/CO over 30 cycles of reaction for the oxygen carrier prepared in example 2.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and specific examples, but the present invention is not limited to the following examples.
The oxygen carrier for preparing the synthesis gas by reforming the chemical chain of methane is a composite metal oxide with a perovskite structure, and the structural general formula is Y xLa1-xFeO3, wherein x is more than 0 and less than 1, and preferably x is 0.05, 0.1, 0.2, 0.4, 0.6 or 0.8.
The preparation method of the oxygen carrier comprises the following steps:
Specifically, the oxygen carrier is prepared by a sol-gel method, firstly, precursors of La, Y and Fe are added according to a required stoichiometric ratio and are completely dissolved in deionized water to form a precursor solution, citric acid solid is weighed and added into the precursor solution to be stirred until the precursors are fully dissolved, and ammonia water is used for regulating the pH value of the solution to 7-8. Then the solution is stirred in a constant temperature water bath until the solution is a viscous colloid, and then the required aerobic carrier can be prepared by drying, grinding and calcining the viscous colloid.
Wherein the La precursor is La (at least one of NO 3)3·6H2 O and H 14ClLaO7; the Y precursor is Y (at least one of NO 3)3·6H2 O and YCl 3; the Fe precursor is at least one of FeCl 3、Fe(NO3)3·9H2 O and FeSO 4; the total concentration of La, Y and Fe precursors in the precursor solution is 1-1.2 mol/L; the amount of citric acid required is 1.5-2.5 times the total metal cation molar amount in the solution; the drying process is drying at 50-80 ℃ for 8-12 hours; the calcining process is calcining at 300-500 ℃ for 2-5 hours and then at 800-1000 ℃ for 2-5 hours).
The oxygen carrier as described above is applied in a methane chemical chain reforming process, in particular the oxygen carrier is circulated between two communicating reactors (fuel reactor and regeneration reactor); wherein in the fuel reactor, the oxygen carrier oxidizes methane to produce syngas; in the regeneration reactor, the oxygen carrier is oxidized and regenerated in an oxidizing atmosphere, and enters the next circulation process; the reaction is carried out under normal pressure, and the reaction temperature is 800-1000 ℃; the fuel reactor is a mixed gas of methane and inert gas, and the oxidizing atmosphere in the regeneration reactor is a mixed gas of carbon dioxide and inert gas, or a mixed gas of water vapor and inert gas, or a mixed gas of oxygen and inert gas, or a mixed gas of water vapor and carbon dioxide.
Wherein, the volume fraction of methane in the mixed gas of methane and inert gas is 2% -100%, the volume fraction of carbon dioxide in the mixed gas of carbon dioxide and inert gas is 2% -100%, the volume fraction of water vapor in the mixed gas of water vapor and inert gas is 2% -100%, and the volume fraction of oxygen in the mixed gas of oxygen and inert gas is 2% -100%.
The oxygen carrier can effectively improve the reactivity of the oxygen carrier and methane, the methane conversion rate is up to 92% or more, if carbon dioxide is adopted as an oxidizing atmosphere, the selectivity of synthesis gas is over 90%, and the oxygen carrier has excellent carbon deposition resistance, wherein H 2/CO is 2, and can be directly used for Fischer-Tropsch synthesis. The oxygen carrier has excellent methane reaction activity and stability in multiple redox cycles. Wherein, if water vapor and water/carbon dioxide are used as oxidizing atmosphere, high-value added products such as high-purity hydrogen, carbon monoxide or synthetic gas can be produced.
Comparative example 1
Preparation of LaFeO 3 oxygen Carrier
Weighing a certain amount of La (NO 3)3·6H2 O and Fe (NO 3)3·9H2 O) according to a stoichiometric ratio, dissolving in deionized water, stirring and dissolving after the solution is completely dissolved, weighing citric acid solid (citric acid: metal cation=2.5:1), regulating the pH value of the solution to 7-8 by ammonia water after the citric acid is fully dissolved, stirring the solution under the condition of constant-temperature water bath at 80 ℃ until the water content of the solution is evaporated to be sticky colloid, then placing the sticky colloid into a blast drying oven at 150 ℃ for drying for 12 hours to obtain a black precursor, fully grinding, placing a sample into a muffle furnace for calcining, firstly calcining at 400 ℃ for 4 hours at constant temperature to remove organic impurities in the sample, grinding the sample again after the sample is cooled to room temperature, then placing the ground sample into particles at 900 ℃ for calcining for 4 hours at constant temperature, pressing the obtained oxygen carrier powder into particles with 20-40 meshes under the pressure of 10MPa, and marking and bagging for standby.
Example 1
Preparation of Y 0.05La0.95FeO3 oxygen Carrier
And (3) weighing a certain amount of Y (NO) 3·6H2O、La(NO3)3·6H2 O and Fe (NO 3)3·9H2 O) according to a stoichiometric ratio, dissolving in deionized water, after the solution is completely dissolved, weighing citric acid solid (citric acid: cation=2.5:1), stirring and dissolving, after the citric acid is fully dissolved, regulating the pH value of the solution to be 7-8 by ammonia water, then placing the solution in a constant-temperature water bath at 80 ℃ for stirring until the water content of the solution is evaporated to be a viscous colloid, then placing the viscous colloid in a blast drying oven at 150 ℃ for drying for 12 hours to obtain a black precursor, fully grinding, placing a sample in a muffle furnace for calcining, firstly, calcining at 400 ℃ for 4 hours at constant temperature to remove organic impurities in the sample, after the sample is cooled to room temperature, grinding again, then placing the ground sample in 900 ℃ for calcining at constant temperature for 4 hours, pressing the obtained oxygen carrier powder into particles of 20-40 meshes under the pressure of 10MPa, and marking and bagging for standby.
Example 2
Preparation of Y 0.1La0.9FeO3 oxygen Carrier
The specific procedure is as in example 1, except that the molar ratio of Y (NO) 3·6H2 O and La (NO 3)3) in the precursor solution is 1:9.
Example 3
Preparation of Y 0.2La0.8FeO3 oxygen Carrier
The specific procedure was as in example 1, except that the molar ratio of Y (NO) 3·6H2 O and La (NO 3)3) in the precursor solution was 2:8.
Example 4
Preparation of Y 0.4La0.8FeO3 oxygen Carrier
The specific procedure was as in example 1, except that the molar ratio of Y (NO) 3·6H2 O and La (NO 3)3) in the precursor solution was 4:6.
Example 5
Preparation of Y 0.6La0.4FeO3 oxygen Carrier
The procedure is as in example 1, except that the molar ratio of Y (NO) 3·6H2 O to La (NO 3)3) in the precursor solution is 6:4.
Example 6
Preparation of Y 0.8La0.2FeO3 oxygen Carrier
The procedure is as in example 1, except that Y (NO) 3·6H2 O and La (NO 3)3 are present in the precursor solution in a molar ratio of 8:2
Example 7
XRD testing of the oxygen carriers prepared in comparative example 1 and examples 1,2, 3 was performed on an X' pert Pro Super type ray diffractometer manufactured by Netherlands PAN ANALYTICAL. The copper target kα line was the light source (λ= 0.15432 nm), the graphite monochromator, and the tube voltage and tube current were 40kV and 40mA, respectively. The X-ray diffraction test results are shown in FIG. 1.
As can be seen from FIG. 1, only the perovskite LaFeO 3 phase diffraction peak can be observed in all oxygen carriers, which indicates that the oxygen carriers after roasting are of pure-phase perovskite structure and no impurity phase is generated. Meanwhile, as the Y substitution amount increases, the LaFeO 3 diffraction peak gradually shifts to a high angle, and the Y 3+ ion radius is used forLess than La 3+ ion radiusIndicating that Y 3+ ion successfully replaces La 3+ ion to enter LaFeO 3 crystal lattice to form Y xLa1-xFeO3 structure.
Example 8
The oxygen carrier prepared in comparative example 1 was evaluated for activity by methane chemical chain reforming reaction using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 900 ℃, the reaction time is 15min, and the reaction pressure is normal pressure. The reactor outlet gas was analyzed on-line using a GAM-200 type mass spectrometer. The reaction results are shown in FIG. 2.
As can be seen from fig. 2, the x=0 oxygen carrier has a small amount of CO 2 generated at the initial stage of the reaction, and a large amount of unreacted methane exists in the process, so that the generation of H 2 and CO both show a tendency of decreasing first and then slowly increasing, which indicates that the methane has lower reactivity and the release rate of lattice oxygen in the oxygen carrier is slower.
Example 9
The oxygen carriers prepared in examples 1 and 5 were evaluated for activity by methane chemical chain reforming reaction using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 900 ℃, the reaction time is 15min, and the reaction pressure is normal pressure. The reactor outlet gas was analyzed on-line using a GAM-200 type mass spectrometer. The reaction results are shown in FIGS. 3 and 4.
As can be seen from fig. 3 and 4, the unreacted methane content of the Y-doped oxygen carrier is greatly reduced compared to the pure LaFeO 3 of comparative example 1, a rapid synthesis gas generation is observed in the initial stage of the reaction (within 2.5 min), and the yield of synthesis gas is significantly improved, indicating that the converted methane is mainly selectively oxidized to synthesis gas. It can be seen that doping of Y significantly increases the activity of the oxygen carrier to react with methane and the rate of lattice oxygen release.
Example 10
Comparative examples 1, 2 and 4 the oxygen carriers prepared in example 1, 2 and 4 were evaluated for the cycle stability of methane chemical chain reforming of the oxygen carriers using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 900 ℃, and the reaction pressure is normal pressure. After the reduction for 8 minutes, the flow rate was switched to Ar purging for 5 minutes at 15ml/min, then the flow rate was switched to oxidizing atmosphere with a composition of 5% CO 2/Ar at 15ml/min, and the reaction temperature was 900℃for 10 minutes. The above procedure was repeated 10 times to test oxygen carrier stability. The reactor outlet gas was analyzed on line using a GAM-200 type mass spectrometer and the stability evaluation results are shown in fig. 5 and 6.
As can be seen from FIG. 5, the methane conversion rate of pure LaFeO 3 is only about 60%, and when the Y doping amount is 0.1 and 0.4 respectively, the methane conversion rate of the oxygen carrier is greatly improved from-60% to 92% and more than 90%, and the oxygen carrier is stable all the time in the 10 times oxidation-reduction process, and has proper H 2/CO (-2).
As can be seen from FIG. 6, the yield and the oxygen yield of the synthesis gas of the pure LaFeO 3 are only about 1.3mmol/g and about 0.6mmol/g, and when a small amount of Y is doped (x=0.1), the yield and the oxygen yield of the synthesis gas are greatly improved to 2.25mmol/g and 1.05mmol/g, 73% and 75% are respectively improved, and the performance is remarkably improved. And each performance of the oxygen carrier after Y doping is kept stable in the 10 times of oxidation-reduction process, and the oxygen carrier has no descending trend. Thus, the doping of Y not only significantly improves the reactivity of the oxygen carrier with methane, but also improves the cycle stability.
The oxygen carriers prepared in example 1 (x=0.05) and example 3 (x=0.2) had similar properties to those of example 2 (x=0.1) and example 4 (x=0.4) described above.
Example 11
XRD testing during oxygen carrier cycling was performed on an X' pert Pro Super type ray diffractometer manufactured by the company PAN ANALYTICAL in the Netherlands, comparative example 1 and example 2. The copper target kα line was the light source (λ= 0.15432 nm), the graphite monochromator, and the tube voltage and tube current were 40kV and 40mA, respectively. The X-ray diffraction test results are shown in fig. 7 and 8.
From fig. 7 and 8, it was found that the perovskite structures of both LaFeO 3 and Y 0.1La0.9FeO3 oxygen carriers were maintained during 10 cycles, demonstrating that the structures were stable. In the methane reduction process, the oxygen carrier doped with Y is subjected to deep reduction, zero-valent iron is generated on the surface of the oxygen carrier, and the oxygen carrier can be used as an active center for adsorbing methane. Although the reactivity of the oxygen carrier and methane is greatly improved after the Y doping, no carbon deposition is found, which indicates that the oxygen supply of the oxygen carrier is sufficient in the reaction process, and the activated methane can be rapidly oxidized to generate synthesis gas. The above results show that the doping of Y not only promotes the deep reduction of Fe, is beneficial to the activation of methane and the great improvement of the oxygen yield, but also obviously improves the migration capability of bulk lattice oxygen, so that the lattice oxygen is continuously transferred to the surface from bulk migration and used for oxidizing the adsorbed and activated methane, which is probably an important reason that the oxygen carrier after the Y doping modification has excellent methane reaction activity, high cycle stability and anti-carbon deposition performance.
Example 12
The oxygen carrier prepared in example 2 was evaluated for the cycle stability of methane chemical chain reforming of the oxygen carrier by using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 900 ℃, and the reaction pressure is normal pressure. After the reduction for 8 minutes, the flow rate was switched to Ar purging for 5 minutes at 15ml/min, then the flow rate was switched to oxidizing atmosphere with a composition of 5% CO 2/Ar at 15ml/min, and the reaction temperature was 900℃for 10 minutes. The above procedure was repeated 30 times to test oxygen carrier stability. The reactor outlet gas was analyzed on-line using a GAM-200 type mass spectrometer. The results of the stability evaluation are shown in fig. 9.
From fig. 9, it can be seen that the methane conversion rate and the synthesis gas selectivity of the Y-doped Y 0.1La0.9FeO3 oxygen carrier can still reach more than 90% even when reaching the 30 th cycle, the molar ratio of H 2 to CO is always maintained between 1.9 and 2.1, the ideal value is close to 2, and the synthesis gas quality is high. The above results indicate that the Y-doped oxygen carrier still exhibits excellent methane reactivity and cycling stability during 30 consecutive high temperature redox reactions.
Example 13
The procedure for the evaluation was identical to that of example 10, except that the regeneration atmosphere was changed to 5% CO 2/Ar or 5%H 2 O/Ar, using the oxygen carrier prepared in example 2.
Example 14
The oxygen carrier prepared in example 1 was evaluated for activity by methane chemical chain reforming reaction using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 800 ℃, the reaction time is 15min, and the reaction pressure is normal pressure.
Example 15
The oxygen carrier prepared in example 5 was evaluated for activity by methane chemical chain reforming reaction using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 950 ℃, the reaction time is 15min, and the reaction pressure is normal pressure.
Example 16
Preparation of Y 0.1La0.9FeO3 oxygen Carrier
And (3) weighing a certain amount of Y (NO) 3·6H2O、La(NO3)3·6H2 O and Fe (NO 3)3·9H2 O) according to a stoichiometric ratio, dissolving in deionized water, after the solution is completely dissolved, weighing citric acid solid (citric acid: cation=2.5:1), stirring and dissolving, after the citric acid is fully dissolved, regulating the pH value of the solution to be 7-8 by ammonia water, then placing the solution in a constant-temperature water bath condition at 70 ℃ for stirring until the water content of the solution is evaporated to be a viscous colloid, then placing the viscous colloid in a blast drying oven at 150 ℃ for drying for 10 hours to obtain a black precursor, fully grinding, placing a sample in a muffle furnace for calcining, firstly, calcining at 400 ℃ for 3 hours at constant temperature to remove organic impurities in the sample, after the sample is cooled to room temperature, grinding again, then placing the ground sample in 800 ℃ for calcining at constant temperature for 5 hours, pressing the obtained oxygen carrier powder into particles with 20-40 meshes under the pressure of 10MPa, and marking and bagging for standby.
Example 17
Preparation of Y 0.2La0.8FeO3 oxygen Carrier
And (3) weighing a certain amount of Y (NO) 3·6H2O、La(NO3)3·6H2 O and Fe (NO 3)3·9H2 O) according to a stoichiometric ratio, dissolving in deionized water, after the solution is completely dissolved, weighing citric acid solid (citric acid: cation=2.5:1), stirring and dissolving, after the citric acid is fully dissolved, regulating the pH value of the solution to be 7-8 by ammonia water, then placing the solution in a constant-temperature water bath condition at 70 ℃ for stirring until the water content of the solution is evaporated to be a viscous colloid, then placing the viscous colloid in a blast drying oven at 150 ℃ for drying for 10 hours to obtain a black precursor, fully grinding, placing a sample in a muffle furnace for calcining, firstly, calcining at 400 ℃ for 5 hours at constant temperature to remove organic impurities in the sample, after the sample is cooled to room temperature, grinding the sample again, then placing the ground sample in a constant-temperature calcining for 2.5 hours at 1000 ℃, pressing the obtained oxygen carrier powder into particles with 20-40 meshes under the pressure of 10MPa, and marking and bagging for standby.
Example 18
The oxygen carriers prepared in example 16 and example 17 were evaluated for activity by methane chemical chain reforming reaction using a fixed bed reactor. The oxygen carrier dosage is 200mg, and the granularity is 20-40 meshes. The fuel gas composition is 5% CH 4/Ar, the flow is 15ml/min, the reaction temperature is 900 ℃, the reaction time is 15min, and the reaction pressure is normal pressure.
The above description is only a preferred example of the present invention and is not intended to limit the present invention in any way; any person skilled in the art can make many possible modifications, equivalents, or improvements to the solution of the present invention using the method described above, without departing from the scope of the solution of the present invention. Therefore, any simple modification, equivalent substitution, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention, unless departing from the technical solution of the present invention.
Claims (4)
1. An oxygen carrier for preparing synthetic gas by methane chemical chain reforming is characterized in that the oxygen carrier has a perovskite structure, the structural formula is Y xLa1-xFeO3, wherein x is more than 0 and less than 1, the oxygen carrier is a cubic crystal system, and Y 3+ ions replace La 3+ ions and enter LaFeO 3 crystal lattice.
2. An oxygen carrier for use in the chemical looping reforming of methane to produce synthesis gas according to claim 1, wherein x is 0.05, 0.1, 0.2, 0.4, 0.6 or 0.8.
3. A method for preparing an oxygen carrier for methane chemical looping reforming to produce synthesis gas, comprising the steps of:
Dissolving precursors of La, Y and Fe in deionized water according to Y xLa1-xFeO3 to form a precursor solution; wherein x is more than 0 and less than 1;
adding citric acid into the precursor solution, stirring until the citric acid is dissolved, adjusting the pH to 7-8, stirring under heating until the citric acid is sticky, drying, grinding and calcining to obtain an oxygen carrier for preparing the synthesis gas by reforming the chemical chain of methane;
The precursor of La is La (at least one of NO 3)3·6H2 O and H 14ClLaO7; the precursor of Y is Y (at least one of NO 3)3·6H2 O and YCl 3; the precursor of Fe is at least one of FeCl 3、Fe(NO3)3·9H2 O and FeSO 4);
The total concentration of the precursors of La, Y and Fe in the precursor solution is 1-1.2 mol/L;
The amount of citric acid is 1.5-2.5 times of the total molar amount of La, Y and Fe.
4. Use of an oxygen carrier according to any one of claims 1 or 2 for the production of synthesis gas by chemical looping reforming of methane, wherein the oxygen carrier is circulated between two communicating fuel reactors and a regeneration reactor; wherein, in the fuel reactor, the oxygen carrier oxidizes methane at 800-1000 ℃ to produce synthesis gas; in a regeneration reactor, the oxygen carrier is oxidized and regenerated at 800-1000 ℃ under an oxidizing atmosphere, and then enters a fuel reactor;
The fuel reactor is filled with a mixed gas of methane and inert gas, and the oxidizing atmosphere is a mixed gas of carbon dioxide and inert gas, a mixed gas of water vapor and inert gas, a mixed gas of oxygen and inert gas or a mixed gas of water vapor and carbon dioxide;
the volume fraction of methane in the mixed gas of methane and inert gas is 2% -100%, the volume fraction of carbon dioxide in the mixed gas of carbon dioxide and inert gas is 2% -100%, the volume fraction of water vapor in the mixed gas of water vapor and inert gas is 2% -100%, and the volume fraction of oxygen in the mixed gas of oxygen and inert gas is 2% -100%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211106977.2A CN115650167B (en) | 2022-09-09 | Oxygen carrier for preparing synthetic gas by methane chemical chain reforming and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211106977.2A CN115650167B (en) | 2022-09-09 | Oxygen carrier for preparing synthetic gas by methane chemical chain reforming and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115650167A CN115650167A (en) | 2023-01-31 |
| CN115650167B true CN115650167B (en) | 2024-07-09 |
Family
ID=
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108855109A (en) * | 2018-07-02 | 2018-11-23 | 西北大学 | A kind of chemical chain partial oxidation methane preparing synthetic gas carrier of oxygen and its preparation method and application |
| CN110876938A (en) * | 2019-11-05 | 2020-03-13 | 天津大学 | Perovskite type composite metal oxide oxygen carrier and preparation method and application thereof |
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108855109A (en) * | 2018-07-02 | 2018-11-23 | 西北大学 | A kind of chemical chain partial oxidation methane preparing synthetic gas carrier of oxygen and its preparation method and application |
| CN110876938A (en) * | 2019-11-05 | 2020-03-13 | 天津大学 | Perovskite type composite metal oxide oxygen carrier and preparation method and application thereof |
Non-Patent Citations (2)
| Title |
|---|
| Dinh Van Tac等.Influence of Lanthanum Content and Annealing Temperature on the Size and Magnetic Properties of Sol–Gel Derived Y1-xLaxFeO3 Nanocrystals.Inorganic Materials.2011,第47卷(第5期),521-526. * |
| Influence of Lanthanum Content and Annealing Temperature on the Size and Magnetic Properties of Sol–Gel Derived Y1-xLaxFeO3 Nanocrystals;Dinh Van Tac等;Inorganic Materials;20111231;第47卷(第5期);521-526 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ding et al. | A novel composite perovskite-based material for chemical-looping steam methane reforming to hydrogen and syngas | |
| Zhao et al. | Synergistic improvements in stability and performance of the double perovskite-type oxides La2− xSrxFeCoO6 for chemical looping steam methane reforming | |
| CN108855109B (en) | Synthetic gas oxygen carrier prepared by oxidizing methane with chemical chain part and preparation method and application thereof | |
| Jiang et al. | Solar hydrogen production via perovskite-based chemical-looping steam methane reforming | |
| Zhao et al. | Effects of Co-substitution on the reactivity of double perovskite oxides LaSrFe2-xCoxO6 for the chemical-looping steam methane reforming | |
| CN111087026B (en) | Chemical chain methane partial oxidation oxygen carrier and preparation method and application thereof | |
| Zhu et al. | Metal modified hexaaluminates for syngas generation and CO2 utilization via chemical looping | |
| CN113135598B (en) | Oxygen carrier for preparing synthesis gas by methane chemical-looping reforming and preparation method and application thereof | |
| CN112844403B (en) | Yttrium manganese nickel perovskite structure catalyst for autothermal reforming of acetic acid to produce hydrogen | |
| Yan et al. | Chemical looping catalytic steam gasification (CLCSG) of algae over La1-xBaxFeO3 perovskites for syngas production | |
| CN114588912B (en) | Preparation method and application of alkali metal doped perovskite catalyst suitable for methane dry reforming | |
| Ngoensawat et al. | Effect of La and Gd substitution in BaFeO3-δ perovskite structure on its catalytic performance for thermochemical water splitting | |
| Cao et al. | Screening loaded perovskite oxygen carriers for chemical looping steam methane reforming | |
| Zhou et al. | Ruddlesden‐Popper‐type perovskite Sr3Fe2O7− δ for enhanced thermochemical energy storage | |
| Xiaoping et al. | Effect of calcination temperature and reaction conditions on methane partial oxidation using lanthanum-based perovskite as oxygen donor | |
| CN112811476B (en) | Nickel-doped brownmillerite type oxygen carrier and preparation method and application thereof | |
| Kim et al. | Surface enrichment of lanthanum on Co3O4 for stable chemical looping combustion | |
| CN110683511B (en) | Methane cracking hydrogen production coupling CO2Reduced chemical looping process | |
| CN115650167B (en) | Oxygen carrier for preparing synthetic gas by methane chemical chain reforming and preparation method and application thereof | |
| CN112408320A (en) | Load type double-active metal composite oxygen carrier and preparation method and application thereof | |
| CN114405511B (en) | Oxygen carrier for preparing synthesis gas and combining CO and hydrogen as well as preparation method and application thereof | |
| CN115626666A (en) | Tricalcium titanium ore type composite metal oxide oxygen carrier and preparation method and application thereof | |
| CN112295566B (en) | Chemical chain methane reforming oxygen carrier and preparation method and application thereof | |
| CN115650167A (en) | Oxygen carrier for preparing synthesis gas by methane chemical-looping reforming and preparation method and application thereof | |
| CN110721691B (en) | CFAN catalyst, preparation thereof and application thereof in methane hydrogen production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant |