CN111790458A - Regeneration method of deactivated methanation catalyst - Google Patents
Regeneration method of deactivated methanation catalyst Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims abstract description 196
- 238000011069 regeneration method Methods 0.000 title claims abstract description 23
- 238000006243 chemical reaction Methods 0.000 claims abstract description 47
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 22
- 230000001681 protective effect Effects 0.000 claims abstract description 22
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 230000008021 deposition Effects 0.000 claims abstract description 15
- 238000012216 screening Methods 0.000 claims abstract description 8
- 238000007599 discharging Methods 0.000 claims abstract description 7
- 238000010405 reoxidation reaction Methods 0.000 claims abstract description 6
- 238000004939 coking Methods 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 79
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 74
- 238000000034 method Methods 0.000 claims description 55
- 229910052757 nitrogen Inorganic materials 0.000 claims description 37
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 19
- 239000001257 hydrogen Substances 0.000 claims description 19
- 229910052739 hydrogen Inorganic materials 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 17
- 239000001301 oxygen Substances 0.000 claims description 17
- 229910052760 oxygen Inorganic materials 0.000 claims description 17
- 230000008929 regeneration Effects 0.000 claims description 11
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 10
- 230000000630 rising effect Effects 0.000 claims description 6
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 4
- 229910052786 argon Inorganic materials 0.000 claims description 2
- 239000001307 helium Substances 0.000 claims description 2
- 229910052734 helium Inorganic materials 0.000 claims description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 229920000049 Carbon (fiber) Polymers 0.000 claims 2
- 125000004432 carbon atom Chemical group C* 0.000 claims 2
- 239000004917 carbon fiber Substances 0.000 claims 2
- 230000002779 inactivation Effects 0.000 abstract description 3
- 238000003912 environmental pollution Methods 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
- 230000000694 effects Effects 0.000 description 13
- 238000010926 purge Methods 0.000 description 12
- 230000003647 oxidation Effects 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 230000002829 reductive effect Effects 0.000 description 10
- 229910002091 carbon monoxide Inorganic materials 0.000 description 8
- 238000005245 sintering Methods 0.000 description 7
- 238000011156 evaluation Methods 0.000 description 6
- 239000002923 metal particle Substances 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 6
- 239000003345 natural gas Substances 0.000 description 6
- 230000036961 partial effect Effects 0.000 description 6
- 238000011946 reduction process Methods 0.000 description 6
- 238000001035 drying Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000003245 coal Substances 0.000 description 4
- 230000009849 deactivation Effects 0.000 description 4
- 230000008030 elimination Effects 0.000 description 4
- 238000003379 elimination reaction Methods 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 238000004220 aggregation Methods 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000005262 decarbonization Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
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- 238000007873 sieving Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000002082 metal nanoparticle Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
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- 238000004064 recycling Methods 0.000 description 2
- 238000003746 solid phase reaction Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- -1 magnesium aluminate Chemical class 0.000 description 1
- ATTFYOXEMHAYAX-UHFFFAOYSA-N magnesium nickel Chemical compound [Mg].[Ni] ATTFYOXEMHAYAX-UHFFFAOYSA-N 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
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- 238000000746 purification Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000010200 validation analysis Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J38/00—Regeneration or reactivation of catalysts, in general
- B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
- B01J38/06—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using steam
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J38/00—Regeneration or reactivation of catalysts, in general
- B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J38/00—Regeneration or reactivation of catalysts, in general
- B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
- B01J38/10—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using elemental hydrogen
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J38/00—Regeneration or reactivation of catalysts, in general
- B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
- B01J38/12—Treating with free oxygen-containing gas
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
- C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
- C07C1/04—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon monoxide with hydrogen
- C07C1/0425—Catalysts; their physical properties
- C07C1/045—Regeneration
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/584—Recycling of catalysts
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a regeneration method of a deactivated methanation catalyst, which comprises the following steps: (1) after the methanation system is stopped, introducing protective gas, cooling and depressurizing the methanation reactor, and then enabling the inactivated methanation catalyst to be in contact reaction with steam; (2) providing protective gas for the catalyst obtained in the step (1), further reducing the temperature and the pressure, and then enabling the catalyst to contact and react with air; (3) discharging the catalyst obtained in the step (2) from the methanation reactor, and screening to remove the crushed and pulverized parts and the coking and caking parts to obtain the catalyst for eliminating carbon deposition and reoxidation; (4) and (4) refilling the catalyst obtained in the step (3) into the methanation reactor, and then enabling the catalyst to be in contact reaction with reducing gas to obtain a regenerated catalyst. The regeneration method is simple, saves cost and avoids environmental pollution caused by inactivation and discarding of the catalyst.
Description
Technical Field
The invention belongs to the technical field of coal-based natural gas. In particular, the present invention relates to a process for the regeneration of a deactivated methanation catalyst.
Background
As a novel modern coal chemical technology, the coal-based natural gas industry in China has made great progress through the development of the last decade. The coal-to-natural gas core technology, namely the synthesis gas methanation process and the catalyst research also make important breakthrough, for example, methanation catalysts independently developed by the great Tang International chemical technology research institute Co., Ltd have successfully realized industrial application in the great Tang flag coal-to-natural gas project and are about to be industrially applied in the great Tang new coal-to-natural gas project.
The methanation catalyst generally uses nickel as an active metal, and the carrier mainly comprises an alumina type, a magnesium aluminate spinel type and a calcium aluminate type. The service life of the methanation catalyst used in industry is 2 years mostly. Catalyst deactivation is a problem encountered during the use of almost all commercial catalysts. Two main reasons for the deactivation of the methanation catalyst during normal use have been found through research: firstly, carbon deposition inactivation is shown in that the catalyst activity is greatly reduced due to the blockage of catalyst pores caused by carbon aggregation, and simultaneously, the catalyst is crushed and pulverized to cause the pressure drop of a catalyst bed layer to be greatly increased and the catalyst is forced to be replaced; secondly, the metal particles are sintered and inactivated, which shows that the active metal nickel is agglomerated, and the number of active centers is greatly reduced.
The conventional recovery treatment of the deactivated catalyst is complex, and a series of complex processes such as acid/alkali dissolution, separation, purification and the like are required to recover metal components in the deactivated catalyst. These conventional recycling methods are expensive and difficult to recycle.
CN 105642372A discloses a recycling method of an inactivated methanation catalyst, which comprises the steps of grinding, crushing, fully burning carbon, adding a forming aid, a lubricant and a pore-forming agent, granulating and pressing a ring to prepare a carrier precursor, drying and roasting the carrier precursor, then soaking a nickel-magnesium solution, and finally drying and roasting to obtain a regenerated methanation catalyst. The regeneration method has complex process, needs more substances for assistance, and still can cause the aggregation of active metal particles by repeated roasting in the process.
CN 103265384A discloses a methanation reaction system and a methanation catalyst regeneration process, wherein the regeneration process comprises on-line carbon deposition and CO on the surface of a catalyst2The regeneration method cannot solve the problem that the pressure drop of a bed layer is greatly increased due to carbon deposition to force the sintering and aggregation of the catalyst and active metal particles.
In conclusion, for the regeneration of the deactivated methanation catalyst, especially for the regeneration of the methanation catalyst deactivated by carbon deposition and/or metal particle sintering, a new simple and convenient regeneration method capable of fully utilizing the characteristics of the catalyst needs to be explored.
Disclosure of Invention
The invention aims to provide a regeneration method for a deactivated methanation catalyst, which is simple and convenient to operate and high in regeneration efficiency, can simultaneously realize regeneration of the methanation catalyst deactivated by carbon deposition and/or metal sintering, and has high catalytic performance and service life.
The above object of the present invention is achieved by the following means.
The invention provides a regeneration method of a deactivated methanation catalyst, which comprises the following steps:
(1) after the methanation system is stopped, introducing protective gas, cooling and depressurizing the methanation reactor, and then enabling the inactivated methanation catalyst to be in contact reaction with steam;
(2) providing protective gas for the catalyst obtained in the step (1), further reducing the temperature and the pressure, and then enabling the catalyst to contact and react with air;
(3) discharging the catalyst obtained in the step (2) from the methanation reactor, and screening to remove the crushed and pulverized parts and the coking and caking parts to obtain the catalyst for eliminating carbon deposition and reoxidation;
(4) and (4) refilling the catalyst obtained in the step (3) into the methanation reactor, and then enabling the catalyst to be in contact reaction with reducing gas to obtain a regenerated catalyst.
Preferably, in the method of the present invention, the deactivated methanation catalyst is a carbon deposit deactivated and/or catalyst sintering deactivated methanation catalyst.
Preferably, in the method of the present invention, the temperature and pressure reduction in step (1) is performed by cooling the methanation reactor to 250-400 ℃ and reducing the pressure to 0.5-1.5 MPa.
Preferably, in the method of the present invention, the temperature and pressure reduction in step (1) is performed by cooling the methanation reactor to 300-350 ℃ and reducing the pressure to 0.5-0.8 MPa.
Preferably, in the method of the present invention, the temperature reduction in the step (1) is performed at a temperature reduction rate of not more than 80 ℃/h, more preferably at a temperature reduction rate of not more than 50 ℃/h.
Preferably, in the method of the present invention, the depressurization in the step (1) is carried out at a depressurization rate of not more than 0.1 MPa/min.
Preferably, in the method of the present invention, the temperature of the steam in the step (1) is 400 to 500 ℃, and the pressure is 2.0 to 5.0 MPa.
Preferably, in the method provided by the invention, the deactivated methanation catalyst in the step (1) is subjected to contact reaction with water vapor for 24-72 hours, and more preferably, for 24-48 hours;
preferably, in the process according to the invention, the ratio of the mass of steam introduced per hour to the volume of deactivated methanation catalyst is in tons (t): cubic meters (m)3) In terms of 0.7:1 to 1.4:1, and more preferably 0.9:1 to 1.2: 1.
Preferably, in the method of the present invention, the temperature and pressure reduction in step (2) is performed by cooling the catalyst obtained in step (1) to 30-80 ℃ and reducing the pressure to 0.1-0.5 MPa.
Preferably, in the method of the present invention, the temperature and pressure reduction in step (2) is performed by cooling the catalyst obtained in step (1) to 30-50 ℃ and reducing the pressure to 0.1-0.5 MPa.
Preferably, the protective gas in step (1) and step (2) is nitrogen, helium or argon; more preferably, the protective gas in step (1) and step (2) is nitrogen;
preferably, the temperature of the protective gas in the step (1) and the step (2) is normal temperature, and the pressure of the protective gas is 1.0-2.0 MPa.
Preferably, in the method of the present invention, the contact reaction with air in the step (2) is performed by a method comprising the steps of:
and introducing air into the methanation reactor, controlling the flow of the air to ensure that the temperature of the catalyst bed layer does not exceed 80 ℃, and then gradually increasing the oxygen content in the mixed gas of the protective gas and the air under the conditions that the temperature rising rate of the catalyst bed layer is controlled to be less than 1 ℃/min and the temperature of the catalyst bed layer does not exceed 80 ℃ after the temperature rising rate of the catalyst bed layer is less than 1 ℃/min until the volume fraction of the oxygen in the mixed gas at the outlet of the methanation reactor is 21 volume percent.
Preferably, in the method, the temperature of the catalyst bed layer is 50-70 ℃.
Preferably, in the method of the present invention, the contact reaction with air in the step (2) is performed by a method comprising the steps of:
and introducing air into the methanation reactor and controlling the flow of the air so that the oxygen content in the mixed gas of the protective gas and the air is controlled within the range of 0.5-2 vol%, and then gradually increasing the oxygen content in the mixed gas of the protective gas and the air until the volume fraction of the oxygen in the mixed gas at the outlet of the methanation reactor is 21 vol% after the temperature rising rate of the catalyst bed layer is less than 1 ℃/min.
Preferably, in the method of the present invention, the contact reaction with air in the step (2) is performed under the following conditions:
the volume of the protective gas and air mixture introduced per hour and the deactivated methaneThe volume ratio of the catalyst is measured in standard cubic meters (Nm)3) Cubic meter (m)3) In an amount of 50:1 to 1000:1, and more preferably 100:1 to 400: 1.
Preferably, in the method of the present invention, the contact reaction with the reducing gas in the step (4) is performed under the following conditions: the reaction temperature is 450-650 ℃, and the reaction pressure is 0.5-1.5 MPa.
Preferably, in the method of the present invention, the contact reaction with the reducing gas in the step (4) is performed under the following conditions: the reaction temperature is 500-550 ℃, and the reaction pressure is 0.5-1 MPa.
Preferably, in the method of the present invention, the reducing gas in the step (4) is a mixed gas of hydrogen and nitrogen.
Preferably, in the method of the present invention, the reducing gas in the step (4) is a mixed gas of hydrogen and nitrogen, wherein the volume of the hydrogen is 20-50 vol%.
Preferably, in the method of the present invention, the contact reaction with the reducing gas in the step (4) is performed under the following conditions: the ratio of the volume of reducing gas introduced per hour to the volume of deactivated methanation catalyst is in standard cubic meters (Nm)3) Cubic meter (m)3) The ratio is 100: 1-2000: 1, preferably 400: 1-1000: 1.
Preferably, in the method of the present invention, the contact reaction with the reducing gas in the step (4) is performed for 4 to 10 hours.
Preferably, in the method of the present invention, the contact reaction with the reducing gas in the step (4) is performed for 6 to 8 hours.
In the method, when the deactivated catalyst is in contact reaction with steam, on one hand, carbon deposition in the deactivated catalyst is promoted to be converted into CO, and the purpose of removing the carbon deposition is achieved; on the other hand, the sintered metal particles are promoted to be converted into metal oxides, and then the metal oxides are further subjected to solid-phase reaction with the carrier. And then the deactivated catalyst is in contact reaction with air, so that the sintered metal particles are further converted into metal oxide to be subjected to solid-phase reaction with the carrier, and meanwhile, a layer of metal oxide film is covered on the surface of the catalyst, so that the violent reaction caused by contact with oxygen in the process of discharging the catalyst is prevented, and the temperature of a catalyst bed layer is prevented from flying. And then screening the deactivated catalyst to remove the parts of crushing, pulverization and coking and caking so as to achieve the purpose of recovering the low pressure drop of the bed layer. And finally, during reduction treatment, the active metal is controllably reduced and separated out from the solid-phase reactant, and the redispersion of the active metal nanoparticles is realized, so that the regeneration of the deactivated catalyst is realized, the problem that the repeated roasting in the prior art easily causes the accelerated deactivation of the sintering of the active metal of the catalyst is solved, the activity of the regenerated catalyst reaches the level of a fresh catalyst, and the expected life of the regenerated catalyst is close to the level of the fresh catalyst.
The invention has the following beneficial effects:
(1) the regeneration method controls the conversion and regeneration of the catalyst through the processes of carbon elimination, oxidation, screening, reduction and the like. The regeneration method of the invention not only can eliminate the carbon deposition to regenerate the carbon deposition deactivated catalyst, but also can remove the parts of crushing, pulverization and coking agglomeration to further reduce the pressure drop of the catalyst bed layer, and simultaneously can disperse the agglomerated metal nano particles again to realize the regeneration of the metal sintering catalyst, thereby solving the problem of accelerated deactivation of the active metal sintering of the catalyst caused by repeated roasting in the prior art;
(2) the regeneration method is simple, saves the cost of the catalyst, and simultaneously avoids environmental pollution caused by inactivation and discarding of the catalyst;
(3) the catalyst regenerated by the method has the activity reaching the level of a fresh catalyst and the service life of the catalyst close to the level of the fresh catalyst, is suitable for the complete methanation process of hydrogen and carbon monoxide under different working conditions, is particularly suitable for the process technology of preparing natural gas from coal, and is also suitable for the process technology of preparing natural gas from coke oven gas.
Detailed Description
The present invention is described in further detail below with reference to specific embodiments, which are given for the purpose of illustration only and are not intended to limit the scope of the invention.
Example 1
(1) Steam decarbonization and partial oxidation of active metals
After the methanation system is stopped, the temperature of the methanation reactor is continuously reduced through a circulating compressor until the outlet temperature of the methanation reactor is 330 ℃, the pressure of the methanation system is reduced to 0.8MPa, the temperature reduction rate is controlled to be not more than 50 ℃/h in the temperature reduction process, and the pressure reduction rate is controlled to be not more than 0.1MPa/min in the pressure reduction process, so that the adverse effect on a catalyst bed layer caused by the over-high speed is prevented. After the methanation system is cooled and depressurized, normal-temperature nitrogen is introduced into the methanation reactor to purge and replace the methanation system. Analyzing and detecting the nitrogen content in the gas at the outlet of the methanation reactor, and judging that the substitution is qualified when the nitrogen content is more than 99 percent. To a methanation reactor (catalyst loading 48.4 m)3) Introducing 4.8MPa water vapor at 450 ℃, controlling the flow rate of the water vapor to be about 55t, simultaneously adjusting the flow rate of nitrogen, controlling the outlet temperature of the methanation reactor to be about 340 ℃, and introducing the water vapor for 24 hours. And during the period of introducing the water vapor, sampling and analyzing the outlet gas of the methanation reactor, and monitoring the hydrogen content in the gas. The carbon elimination and partial oxidation degree of the catalyst are judged by the hydrogen content. After the water vapor is cut off, hot nitrogen is adopted to purge and dry the methanation reactor, the duration of purging and drying is 4 hours, and the damage influence of water vapor condensation on the catalyst is prevented.
(2) Oxidation of reactive metals with air
And (3) cooling and purging the methanation system by adopting nitrogen with the temperature of normal temperature and the pressure of 1.5MPa, controlling the cooling speed of the catalyst bed layer to be not more than 50 ℃/h, reducing the bed layer temperature of the catalyst to 50 ℃ and reducing the pressure to 0.3 MPa. After the temperature of the catalyst bed layer is stable, slowly introducing air into the methanation reactor, and adjusting the flow of the air and the nitrogen to ensure that the oxygen content in the mixed gas of the air and the nitrogen is 1 volume percent, wherein the volume flow of the mixed air is controlled to be 15000Nm3At this point, the catalyst bed temperature was 60 ℃. When the temperature rise rate of the catalyst bed layer is less than 1 ℃/min, gradually increasing the oxygen content in the mixed gas of nitrogen and air to 21 percent, and strictly controlling the temperature of the catalyst bed layer to be less than 80 ℃ and the temperature rise of the bed layer to be less than 1 ℃/min in the process.
(3) Catalyst unloading agent sieving
And (3) discharging the catalyst after the reaction of the steam and the air from the methanation reactor, and screening to remove the crushed, pulverized, coked and agglomerated parts to obtain the catalyst for eliminating carbon deposition and reoxidation.
(4) Catalyst reduction
The catalyst obtained in the step (3) is filled back into the original reactor and is in contact reaction with reducing gas (mixed gas of hydrogen and nitrogen, wherein the volume percentage of the hydrogen is 50 percent) at the temperature of 550 and the pressure of 0.5MPa, and the flow rate of the reducing gas is controlled at 15000Nm3And h, reducing for 6h to obtain the regenerated catalyst I.
Example 2
(1) Steam decarbonization and partial oxidation of active metals
After the methanation system is stopped, the temperature of the methanation reactor is continuously reduced through a circulating compressor until the outlet temperature of the methanation reactor is 300 ℃, the pressure of the methanation system is reduced to 0.5MPa, the temperature reduction rate is controlled to be not more than 50 ℃/h in the temperature reduction process, and the pressure reduction rate is controlled to be not more than 0.1MPa/min in the pressure reduction process, so that the adverse effect on a catalyst bed layer caused by the over-high speed is prevented. After the methanation system is cooled and depressurized, normal-temperature nitrogen is introduced into the methanation reactor to purge and replace the methanation system. Analyzing and detecting the nitrogen content in the gas at the outlet of the methanation reactor, and judging that the substitution is qualified when the nitrogen content is more than 99 percent. To a methanation reactor (catalyst loading 8.1 m)3) Introducing 4.0MPa water vapor at 400 ℃, controlling the flow rate of the water vapor to be about 7.5t, simultaneously adjusting the flow rate of nitrogen, controlling the outlet temperature of the methanation reactor to be about 300 ℃, and introducing the water vapor for 48 hours. And during the period of introducing the water vapor, sampling and analyzing the outlet gas of the methanation reactor, and monitoring the hydrogen content in the gas. The carbon elimination and partial oxidation degree of the catalyst are judged by the hydrogen content. After the water vapor is cut off, hot nitrogen is adopted to purge and dry the methanation reactor, the duration of purging and drying is 6 hours, and the damage influence of the water vapor condensation on the catalyst is prevented.
(2) Oxidation of reactive metals with air
And (3) cooling and purging the methanation system by adopting nitrogen with the temperature of normal temperature and the pressure of 1.0MPa, controlling the cooling speed of the catalyst bed layer to be not more than 50 ℃/h, reducing the bed layer temperature of the catalyst to 40 ℃ and reducing the pressure to 0.5 MPa. After the temperature of the catalyst bed layer is stable, slowly introducing air into the methanation reactor, and adjusting the flow of the air and the nitrogen to ensure that the oxygen content in the mixed gas of the air and the nitrogen is 1 volume percent, wherein the volume flow of the mixed air is controlled to be 2000Nm3At this point, the catalyst bed temperature was 50 ℃. When the temperature rise rate of the catalyst bed layer is less than 1 ℃/min, gradually increasing the oxygen content in the mixed gas of nitrogen and air to 21 percent, and strictly controlling the temperature of the catalyst bed layer to be less than 80 ℃ and the temperature rise of the bed layer to be less than 1 ℃/min in the process.
(3) Catalyst unloading agent sieving
And (3) discharging the catalyst after the reaction of the steam and the air from the methanation reactor, and screening to remove the crushed, pulverized, coked and agglomerated parts to obtain the catalyst for eliminating carbon deposition and reoxidation.
(4) Catalyst reduction
The catalyst obtained in the step (3) is filled back into the original reactor and is in contact reaction with reducing gas (mixed gas of hydrogen and nitrogen, wherein the volume percentage of the hydrogen is 50 percent) at the temperature of 500 ℃ and the pressure of 0.5MPa, and the flow rate of the reducing gas is controlled to be 2500Nm3And/h, reducing for 8h to obtain a regenerated catalyst II.
Example 3
(1) Steam decarbonization and partial oxidation of active metals
After the methanation system is stopped, the temperature of the methanation reactor is continuously reduced through a circulating compressor until the outlet temperature of the methanation reactor is 350 ℃, the pressure of the methanation system is reduced to 0.8MPa, the temperature reduction rate is controlled to be not more than 50 ℃/h in the temperature reduction process, and the pressure reduction rate is controlled to be not more than 0.1MPa/min in the pressure reduction process, so that the adverse effect on a catalyst bed layer caused by the over-high speed is prevented. After the methanation system is cooled and depressurized, normal-temperature nitrogen is introduced into the methanation reactor to purge and replace the methanation system. Analysis and detection of methanation reactor vent gasAnd when the nitrogen content in the body is more than 99%, the displacement is qualified. To a methanation reactor (catalyst loading 0.57 m)3) Introducing steam of 5.0MPa and 500 ℃, controlling the flow rate of the steam to be about 0.7t, simultaneously adjusting the flow rate of nitrogen, controlling the outlet temperature of the methanation reactor to be about 350 ℃, and introducing the steam for 24 hours. And during the period of introducing the water vapor, sampling and analyzing the outlet gas of the methanation reactor, and monitoring the hydrogen content in the gas. The carbon elimination and partial oxidation degree of the catalyst are judged by the hydrogen content. After the water vapor is cut off, hot nitrogen is adopted to purge and dry the methanation reactor, the duration of purging and drying is 4 hours, and the damage influence of water vapor condensation on the catalyst is prevented.
(2) Oxidation of reactive metals with air
And (3) cooling and purging the methanation system by adopting nitrogen with the temperature of normal temperature and the pressure of 2.0MPa, controlling the cooling speed of the catalyst bed layer to be not more than 50 ℃/h, reducing the bed layer temperature of the catalyst to 30 ℃ and reducing the pressure to 0.1 MPa. After the temperature of the catalyst bed layer is stable, slowly introducing air into the methanation reactor, and adjusting the flow of the air and the nitrogen to ensure that the oxygen content in the mixed gas of the air and the nitrogen is 1 volume percent, wherein the volume flow of the mixed air is controlled to be 300Nm3The catalyst bed temperature was 35 ℃ at this time. When the temperature rise rate of the catalyst bed layer is less than 1 ℃/min, gradually increasing the oxygen content in the mixed gas of nitrogen and air to 21 percent, and strictly controlling the temperature of the catalyst bed layer to be less than 80 ℃ and the temperature rise of the bed layer to be less than 1 ℃/min in the process.
(3) Catalyst unloading agent sieving
And (3) discharging the catalyst after the reaction of the steam and the air from the methanation reactor, and screening to remove the crushed, pulverized, coked and agglomerated parts to obtain the catalyst for eliminating carbon deposition and reoxidation.
(4) Catalyst reduction
The catalyst obtained in the step (3) is filled back into the original reactor and is in contact reaction with reducing gas (mixed gas of hydrogen and nitrogen, wherein the volume percentage of the hydrogen is 20 percent) at the temperature of 550 ℃ and the pressure of 1.0MPa, and the flow rate of the reducing gas is controlled to be 30 percent0Nm3And/h, reducing for 8h to obtain a regenerated catalyst III.
A comparative validation of regenerated catalyst versus fresh catalyst is given below.
The activity of the regenerated catalyst I, the regenerated catalyst II and the regenerated catalyst III is evaluated and compared with the activity of a fresh methanation catalyst. Wherein the regenerated catalyst I, the regenerated catalyst II, the regenerated catalyst III and the fresh methanation catalyst all adopt the same evaluation conditions (simulating the industrial actual operation conditions): 20ml of the catalyst was charged into a tubular reactor having an inner diameter of 20mm, a catalyst loading height of 50mm, and a mixed gas (39.43 vol% of H therein)28.55 vol.% CO, 48.64 vol.% CH43.38 vol.% CO212.80% by volume H2O) at a reaction pressure of 3.1MPa, a catalyst inlet temperature of 300 ℃ or a catalyst hot spot temperature of 620 ℃ and an evaluation space velocity of 15000h-1Under the evaluation conditions of (3), the catalyst activity parameters were measured.
The activity data for regenerated catalyst I, regenerated catalyst II, regenerated catalyst III and fresh methanation catalyst are listed in Table 1.
Table 1 catalytic activity data
As can be seen from Table 1, the activity of the regenerated methanation catalyst is compared with that of the fresh methanation catalyst, and the CO and CO of the regenerated catalyst are evaluated at an inlet temperature of 300 DEG C2The conversion rate and the fresh catalyst are basically equal; CO and CO of the regenerated catalyst at a hotspot temperature of 620 ℃ evaluation2Conversion and fresh catalyst decreased slightly. The regenerated catalyst hot spot locations are consistent with the fresh catalyst. The evaluation shows that the catalytic activity of the regenerated methanation catalyst substantially reaches the level of the fresh catalyst.
The regenerated catalyst I was subjected to a 1000-hour life investigation experiment at a hot spot of 620 ℃. The 1000h lifetime study test results are shown in table 2.
TABLE 2 regenerated catalyst I1000 h Life test results
As can be seen from Table 2, the regenerated catalyst had CO and CO during the 1000h lifetime examination2The conversion rate is kept stable basically, the position of a catalyst hot spot is shifted down to 15mm from 12mm, the expected life of the regenerated catalyst is estimated to be about 13000h according to the downward shifting rate of the catalyst hot spot, and the expected life is slightly reduced from 16000h of the design service life of a fresh catalyst.
In conclusion, by combining the activity evaluation of the regenerated catalyst and the 1000h life investigation experiment result, the activity of the regenerated catalyst basically reaches the level of a fresh catalyst, and the expected life is close to the level of the fresh catalyst.
Claims (11)
1. A process for the regeneration of a deactivated methanation catalyst, comprising the steps of:
(1) after the methanation system is stopped, introducing protective gas, cooling and depressurizing the methanation reactor, and then enabling the inactivated methanation catalyst to be in contact reaction with steam;
(2) providing protective gas for the catalyst obtained in the step (1), further reducing the temperature and the pressure, and then enabling the catalyst to contact and react with air;
(3) discharging the catalyst obtained in the step (2) from the methanation reactor, and screening to remove the crushed and pulverized parts and the coking and caking parts to obtain the catalyst for eliminating carbon deposition and reoxidation;
(4) and (4) refilling the catalyst obtained in the step (3) into the methanation reactor, and then enabling the catalyst to be in contact reaction with reducing gas to obtain a regenerated catalyst.
2. The method of claim 1, wherein the deactivated methanation catalyst is a carbon-deactivated and/or catalyst-sintered deactivated methanation catalyst.
3. The method according to claim 1, wherein the temperature and pressure reduction in the step (1) is carried out by cooling the methanation reactor to 250-400 ℃ and reducing the pressure to 0.5-1.5 MPa;
preferably, the temperature and pressure reduction in the step (1) is carried out by cooling the methanation reactor to 300-350 ℃ and reducing the pressure to 0.5-0.8 MPa;
preferably, the temperature reduction in the step (1) is carried out at a temperature reduction rate of not more than 80 ℃/h, more preferably at a temperature reduction rate of not more than 50 ℃/h;
preferably, the pressure reduction in the step (1) is performed at a pressure reduction rate of not more than 0.1 MPa/min.
4. The method according to claim 1, wherein the temperature of the water vapor in the step (1) is 400 to 500 ℃ and the pressure is 2.0 to 5.0 MPa;
preferably, the deactivated methanation catalyst in the step (1) is subjected to contact reaction with water vapor for 24-72 hours, and more preferably, for 24-48 hours;
preferably, the ratio of the mass of steam fed in per hour to the volume of deactivated methanation catalyst is in tons: the ratio of the carbon atoms to the carbon atoms is 0.7:1 to 1.4:1 in cubic meter, and more preferably 0.9:1 to 1.2:1 in cubic meter.
5. The method according to claim 1, wherein the temperature and pressure reduction in the step (2) is carried out by cooling the catalyst obtained in the step (1) to 30-80 ℃ and reducing the pressure to 0.1-0.5 MPa;
preferably, the temperature and pressure reduction in the step (2) is carried out by cooling the catalyst obtained in the step (1) to 30-50 ℃ and reducing the pressure to 0.1-0.5 MPa;
preferably, the protective gas in step (1) and step (2) is nitrogen, helium or argon; more preferably, the protective gas in step (1) and step (2) is nitrogen;
preferably, the temperature of the protective gas in the step (1) and the step (2) is normal temperature, and the pressure of the protective gas is 1.0-2.0 MPa.
6. The method according to claim 1, wherein the contact reaction with air in the step (2) is performed by a method comprising the steps of:
introducing air into the methanation reactor, controlling the flow of the air to ensure that the temperature of the catalyst bed layer does not exceed 80 ℃, and then gradually increasing the oxygen content in the mixed gas of the protective gas and the air under the conditions that the temperature rising rate of the catalyst bed layer is controlled to be less than 1 ℃/min and the temperature of the catalyst bed layer does not exceed 80 ℃ after the temperature rising rate of the catalyst bed layer is less than 1 ℃/min until the volume fraction of the oxygen in the mixed gas at the outlet of the methanation reactor is 21 volume percent;
preferably, the temperature of the catalyst bed layer is 50-70 ℃.
7. The method according to claim 1, wherein the contact reaction with air in the step (2) is performed by a method comprising the steps of:
and introducing air into the methanation reactor and controlling the flow of the air so that the oxygen content in the mixed gas of the protective gas and the air is controlled within the range of 0.5-2 vol%, and then gradually increasing the oxygen content in the mixed gas of the protective gas and the air until the volume fraction of the oxygen in the mixed gas at the outlet of the methanation reactor is 21 vol% after the temperature rising rate of the catalyst bed layer is less than 1 ℃/min.
8. The method according to claim 1, wherein the contact reaction with air in the step (2) is carried out under the following conditions:
the ratio of the volume of the protective gas and air mixture introduced per hour to the volume of the deactivated methanation catalyst is calculated in standard cubic meters: the ratio of cubic meter is 50: 1-1000: 1, and more preferably 100: 1-400: 1.
9. The method according to claim 1, wherein the contact reaction with the reducing gas in the step (4) is carried out under the following conditions: the reaction temperature is 450-650 ℃, and the reaction pressure is 0.5-1.5 MPa;
preferably, the contact reaction with the reducing gas in the step (4) is carried out under the following conditions: the reaction temperature is 500-550 ℃, and the reaction pressure is 0.5-1 MPa;
preferably, the reducing gas in the step (4) is a mixed gas of hydrogen and nitrogen;
preferably, the reducing gas in the step (4) is a mixed gas of hydrogen and nitrogen, wherein the volume of the hydrogen accounts for 20-50% of the volume of the mixed gas.
10. The method according to claim 1, wherein the contact reaction with the reducing gas in the step (4) is carried out under the following conditions: the ratio of the volume of reducing gas introduced per hour to the volume of deactivated methanation catalyst is calculated in standard cubic meters: the ratio of the carbon fiber to the carbon fiber is 100: 1-2000: 1 in cubic meter, and preferably 400: 1-1000: 1.
11. The method according to claim 1, wherein the contact reaction with the reducing gas in the step (4) is carried out for 4-10 h;
preferably, the contact reaction with the reducing gas in the step (4) is carried out for 6-8 hours.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103265394A (en) * | 2013-05-27 | 2013-08-28 | 神华集团有限责任公司 | Methanation reaction system and regeneration technology of methanation catalyst |
| CN105642372A (en) * | 2016-03-21 | 2016-06-08 | 中国华能集团清洁能源技术研究院有限公司 | Recycling method of deactivated methanation catalyst |
| CN107987906A (en) * | 2016-10-26 | 2018-05-04 | 中国石油天然气股份有限公司 | A kind of method for producing methane |
| CN109107616A (en) * | 2018-07-30 | 2019-01-01 | 中国华能集团有限公司 | A kind of regeneration method inactivating methanation catalyst |
| CN109647436A (en) * | 2018-12-11 | 2019-04-19 | 中科廊坊过程工程研究院 | A kind of regeneration method of transition metal decaying catalyst |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103265394A (en) * | 2013-05-27 | 2013-08-28 | 神华集团有限责任公司 | Methanation reaction system and regeneration technology of methanation catalyst |
| CN105642372A (en) * | 2016-03-21 | 2016-06-08 | 中国华能集团清洁能源技术研究院有限公司 | Recycling method of deactivated methanation catalyst |
| CN107987906A (en) * | 2016-10-26 | 2018-05-04 | 中国石油天然气股份有限公司 | A kind of method for producing methane |
| CN109107616A (en) * | 2018-07-30 | 2019-01-01 | 中国华能集团有限公司 | A kind of regeneration method inactivating methanation catalyst |
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