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CN-121975539-A - Biomass pyrolysis gasification coupling method and system

CN121975539ACN 121975539 ACN121975539 ACN 121975539ACN-121975539-A

Abstract

The invention relates to the technical field of biomass treatment, and particularly discloses a biomass pyrolysis gasification coupling method and system. The method comprises the steps of (1) carrying out pyrolysis reaction on biomass to generate pyrolysis oil gas and semicoke, (2) carrying out gasification reaction on the semicoke and a gasifying agent in contact with a tar cracking catalyst in a fluidized state to obtain gasification gas and gasification residues, (3) carrying out reforming reaction on the gasification gas in contact with a methane reforming catalyst in the fluidized state to obtain crude synthesis gas, and (4) purifying the crude synthesis gas to obtain synthesis gas. The biomass pyrolysis gasification coupling method provided by the invention can not only remarkably reduce the content of methane in the synthesis gas and improve the yield of the synthesis gas and the quality of the synthesis gas, but also improve the continuous stability of the reaction, reduce the purification difficulty of the crude synthesis gas, simplify the flow, and be suitable for industrialized popularization.

Inventors

  • HUANG LINGXIANG
  • ZHANG XUHUI
  • XU RUN
  • XIA GUOFU
  • LUAN XUEBIN
  • HUANG XINYI

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260505
Application Date
20241031

Claims (10)

  1. 1. A biomass pyrolysis gasification coupling method, characterized in that the method comprises the following steps: (1) Biomass is subjected to pyrolysis reaction to generate pyrolysis oil gas and semicoke; (2) In a fluidized state, the semicoke and the gasifying agent are contacted with a tar cracking catalyst to carry out gasification reaction, so as to obtain gasification gas and gasification residues; (3) In a fluidized state, the gasification gas contacts a methane reforming catalyst to carry out reforming reaction to obtain crude synthesis gas; (4) And purifying the crude synthesis gas to obtain synthesis gas.
  2. 2. The coupling process according to claim 1, wherein the pyrolysis reaction operating conditions of the biomass comprise a pyrolysis temperature of 400-1000 ℃, preferably 700-800 ℃, a pyrolysis pressure of 0.1-5Mpa, preferably 0.1-1Mpa, a pyrolysis time of 1-4h, preferably 1-2h.
  3. 3. The coupling method according to claim 1 or 2, wherein the gasifying agent is selected from one or more of high temperature water vapor, air, oxygen, preferably high temperature water vapor.
  4. 4. The coupling method according to any one of claims 1-3, wherein the tar cracking catalyst comprises a carrier I and an active component I, wherein the carrier I is selected from one or more of CaO, mgO, al 2 O 3 , olivine and mayenite, and the active component I is selected from one or more of Co, mo, ni, ce; Preferably, the mass content of the carrier I is 88-98%, preferably 92-96%, and the mass content of the active component is 2-12%, preferably 4-8%, based on the total mass of the tar cracking catalyst.
  5. 5. The coupling method according to any one of claims 1 to 4, wherein the operation conditions of the gasification reaction include a gasification reaction temperature of 600 to 900 ℃, preferably 700 to 800 ℃, a gasification reaction pressure of 0.1 to 5Mpa, preferably 0.1 to 1Mpa, a gasification reaction residence time of 0.5 to 3.5s, preferably 1.5 to 2s, a fluidization linear velocity of 0.1 to 4m/s, preferably 1 to 3m/s, a mass ratio of semicoke to gasifying agent of 1:1 to 3.5, preferably 1:1.5 to 2.5, and a tar cracking catalyst packing density of 700 to 900Kg/m 3 , preferably 800 to 900Kg/m 3 .
  6. 6. The coupling process according to any one of claims 1-5, wherein the methane reforming catalyst comprises a support II and an active component II, wherein the support II is selected from one or more of Al 2 O 3 、SiO 2 、MgO、C 12 A 7 , preferably Al 2 O 3 and MgO, and the active component II is selected from one or more of Ni, fe, mo, zn, preferably Ni and/or Fe; preferably, the mass content of the carrier II is 90-99%, preferably 93-95%, and the mass content of the active component II is 1-10%, preferably 5-7%, based on the total mass of the methane reforming catalyst.
  7. 7. The coupling method according to any one of claims 1 to 6, wherein the operating conditions of the reforming reaction include a reforming reaction temperature of 700 to 1000 ℃, preferably 700 to 900 ℃, a reforming reaction pressure of 0.1 to 5Mpa, preferably 0.1 to 1Mpa, a fluidization linear velocity of 0.1 to 4m/s, preferably 1 to 3m/s, and a methane reforming catalyst packing density of 800 to 1000Kg/m 3 , preferably 900 to 1000Kg/m 3 .
  8. 8. The coupling method according to any one of claims 1-7, wherein the crude synthesis gas is subjected to dust removal treatment to obtain dust-removed synthesis gas and an inactivated catalyst, wherein the inactivated catalyst is regenerated and returned to a reforming reaction for recycling, and the dust-removed synthesis gas is introduced into a pyrolysis reaction for supplying heat for the pyrolysis reaction; Preferably, the dedusted synthesis gas is first introduced into the pyrolysis reaction for supplying heat to the pyrolysis reaction, and then is heat exchanged with demineralised water for producing low temperature water vapour.
  9. 9. The coupling method of claim 8, wherein when the gasifying agent is high-temperature water vapor, the pyrolysis oil gas is dedusted and used as fuel for heating the low-temperature water vapor to produce high-temperature vapor.
  10. 10. The biomass pyrolysis gasification coupling system is characterized by comprising a pyrolysis furnace 100, a fluidized bed gasification furnace (200) and a first dust remover (300), wherein the fluidized bed gasification furnace (200) is a zoned fluidized bed gasification furnace and comprises a cracking zone (201) and a reforming zone (202), a filter (203) is arranged between the cracking zone (201) and the reforming zone (202), the cracking zone (201) is provided with a semicoke inlet (2011), a gasifying agent inlet (2012) and a gasification residue outlet 2013, and the reforming zone 202 is provided with a feed inlet (2021), a raw synthesis gas outlet (2022) and an optional catalyst circulation port (2023); wherein the solid phase outlet of the pyrolysis furnace (100) is connected with the semicoke inlet (2011), and the raw synthesis gas outlet (2022) is connected with the first dust collector (300).

Description

Biomass pyrolysis gasification coupling method and system Technical Field The invention relates to the technical field of biomass treatment, in particular to a biomass pyrolysis gasification coupling method and system. Background Synthesis gas is a mixed gas rich in H 2, CO and small amounts of CO 2 that can be used as an intermediate for refining or synthesizing various high quality liquid fuels and chemicals. Biomass contains abundant C and H elements and can be used for preparing synthesis gas. The biomass to produce the synthesis gas has the following two outstanding advantages that 1) biomass is a renewable resource and has rich sources, and 2) the biomass synthesis gas is taken as an intermediate to synthesize very various chemicals and high-quality liquid fuels. At present, two technical approaches exist for preparing synthetic gas from biomass, namely, firstly, directly gasifying the biomass in a gasification furnace, then reforming and converting generated fuel gas into synthetic gas, and secondly, firstly, carrying out medium-temperature fast pyrolysis on the biomass to obtain bio-oil, and then gasifying the bio-oil, and preparing the synthetic gas through reforming and converting. But both of these techniques generally suffer from the following problems: (1) The biomass gasification reactor has low universality for gasification tests of various biomass or mixed biomass raw materials and high requirements for the raw materials; (2) The gas production component obtained by the existing biomass gasification technology does not meet the requirements of chemical synthesis technology. The H/C molar ratio in the produced gas is generally lower, the theoretical proportion of synthesis of chemicals such as methanol, ethanol and the like can not be reached, and the content of CO 2、CH4 in the produced gas is higher, so that the synthesis of chemical products in the later period is influenced; (3) A large amount of tar which is difficult to utilize is produced in the process of preparing the synthetic gas by gasifying the biomass, and the gas production effect and the operation of a system are affected; (4) Most of domestic researches on the preparation of synthesis gas from biomass still stay in a laboratory stage at present, and industrial application is difficult to realize. CN117285964A discloses a device and a method for preparing synthetic gas by biomass gasification coupling non-catalytic conversion, wherein the method adopts a non-catalytic converter to convert methane and tar generated by gasification into effective gas components CO and H 2, and the obtained synthetic gas contains 30-40mol% of H 2, 25-35mol% of CO, 0.5-2.5mol% of tar and 7-15mol% of methane. The methane content in the synthesis gas obtained in the way is about 10mol percent, and the H/C mole ratio in the synthesis gas is lower, so that the subsequent processes of synthesizing methanol and the like are influenced. Therefore, it is desirable to provide a biomass pyrolysis gasification coupling method and system capable of producing synthesis gas with the advantages of low carbon dioxide and methane content and high H/C molar ratio and improving the yield of the synthesis gas. Disclosure of Invention The invention aims to solve the problems of high tar yield, high carbon dioxide and methane content in the synthesis gas, low H/C molar ratio, low synthesis gas yield and the like in the preparation of the synthesis gas by biomass, and can produce the synthesis gas with the advantages of low carbon dioxide and methane content and high H/C molar ratio, and the biomass pyrolysis gasification coupling method and system can improve the synthesis gas yield. The first aspect of the invention provides a biomass pyrolysis gasification coupling method, wherein the method comprises the following steps: (1) Biomass is subjected to pyrolysis reaction to generate pyrolysis oil gas and semicoke; (2) In a fluidized state, the semicoke and the gasifying agent are contacted with a tar cracking catalyst to carry out gasification reaction, so as to obtain gasification gas and gasification residues; (3) In a fluidized state, the gasification gas contacts a methane reforming catalyst to carry out reforming reaction to obtain crude synthesis gas; (4) And purifying the crude synthesis gas to obtain synthesis gas. The second aspect of the invention provides a biomass pyrolysis gasification coupling system, wherein the system comprises a pyrolysis furnace 100, a fluidized bed gasification furnace 200 and a first dust remover 300, wherein the fluidized bed gasification furnace 200 is a zoned fluidized bed gasification furnace and comprises a cracking zone 201 and a reforming zone 202, a filter 203 is arranged between the cracking zone 201 and the reforming zone 202, the cracking zone 201 is provided with a semicoke inlet 2011, a gasifying agent inlet 2012 and a gasification residue outlet 2013, and the reforming zone 202 is provided with a feed inlet 2021, a raw s