CN112625757A - Device and method for fluidized catalytic gasification of pulverized coal - Google Patents

Device and method for fluidized catalytic gasification of pulverized coal Download PDF

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Publication number
CN112625757A
CN112625757A CN201910905967.7A CN201910905967A CN112625757A CN 112625757 A CN112625757 A CN 112625757A CN 201910905967 A CN201910905967 A CN 201910905967A CN 112625757 A CN112625757 A CN 112625757A
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gasification
bed
gas
furnace
pyrolysis
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钟思青
徐俊
霍威
高攀
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/58—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels combined with pre-distillation of the fuel
    • C10J3/60—Processes
    • C10J3/64—Processes with decomposition of the distillation products
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/721—Multistage gasification, e.g. plural parallel or serial gasification stages
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/723—Controlling or regulating the gasification process
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/725—Redox processes
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/82—Gas withdrawal means
    • C10J3/84—Gas withdrawal means with means for removing dust or tar from the gas
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0913—Carbonaceous raw material
    • C10J2300/0916—Biomass
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0913—Carbonaceous raw material
    • C10J2300/093—Coal
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0969—Carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0973—Water
    • C10J2300/0976—Water as steam
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0983—Additives
    • C10J2300/0986—Catalysts
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/12—Heating the gasifier
    • C10J2300/1223—Heating the gasifier by burners
    • 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
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Combustion & Propulsion (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
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  • Industrial Gases (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Abstract

The invention discloses a device for fluidized catalytic gasification of pulverized coal, which comprises: a feeder; the fast bed pyrolysis furnace is connected with the feeding machine through a feeding inclined pipe; the fluidized bed gasification furnace is connected with the fast bed pyrolysis furnace; the lower inlet of the fast bed gasification furnace is connected with the upper outlet of the fluidized bed gasification furnace; the upper inlet of the fluidized bed combustion chamber is connected with the lower outlet of the fluidized bed gasification furnace; a fine powder settling/stripping device connected with the fast bed pyrolysis furnace through a gasification inclined pipe. The invention also discloses a method for fluidized catalytic gasification of pulverized coal. The invention has the characteristics of high carbon conversion rate, high gasification strength, high pulverized coal utilization rate, wide gasified coal type adaptability, reasonable energy utilization, stable and efficient device operation.

Description

Device and method for fluidized catalytic gasification of pulverized coal
Technical Field
The invention belongs to the field of coal gasification, and relates to a device and a method for fluidized catalytic gasification of pulverized coal.
Background
Coal, petroleum and natural gas are three major primary energy sources in the world, wherein coal accounts for about 79% of the world energy reserves, and coal is one of the main fuel resources for generating power, heat, coal tar processing and by-product asphalt. China is a country with coal as a main energy structure, and the coal cannot be changed for a long time in the future, and according to statistics, the coal reaches 63.7% in a primary energy consumption structure of China in 2015. With the increasing shortage of petroleum resources, the effective utilization of coal resources has become a strategy for sustainable development of energy in China. The reserve of low-rank coal in China accounts for more than 55% of the total amount of coal resources, but the low-rank coal has high water content, low coalification degree and low direct combustion efficiency, thereby not only wasting resources, but also polluting the environment and causing the emission of acid rain, PM2.5, SOx, NOx and other greenhouse gases. The coal gasification technology is a key technology for realizing clean, efficient and comprehensive utilization of coal, is an important way for coal conversion, and is also one of key technologies for synthesizing chemicals, combined cycle power generation and preparing substitute natural gas from coal. The method is a key for realizing sustainable energy development in China and is an effective way for solving the global energy and environment problems.
China is the largest coal gasification technology application market in the world, and at present, various coal gasification technologies have been successfully applied in industrialization. The prior art widely belongs to an entrained flow gasification technology, and the carbon conversion rate is improved at the cost of high temperature and high pressure, so that the problems of high energy consumption, difficult gas purification, strict requirements on equipment and the like are caused. At the same time, the excessive operating temperatures of entrained flow slag gasification technology increase the investment, maintenance and operating costs of the entrained flow. Research reports of the American Electric Power Research Institute (EPRI) indicate that the existing industrial entrained-flow gasifier is not suitable for the gasification of high-ash and high-ash fusion-point coal, and the world needs an industrialized fluidized bed gasification technology. The fluidized bed technology has the nature of adapting to high ash melting point and high ash coal types no matter combustion or gasification, and the evidence proves that the circulating fluidized bed boiler successfully combusts coal gangue.
The natural gas is a high-quality fuel and an important chemical raw material, and has the advantages of safety, reliability, environmental protection and the like. With the rapid development of the economy of China and the acceleration of the urbanization pace, the demand for natural gas is increasing day by day. The natural gas yield of China is the amount which cannot meet the demand of natural gas, the contradiction between supply and demand is increasingly prominent, the supply gap can only be made up by relying on import, and the energy safety of China is greatly influenced. The existing coal-based natural gas technology can be divided into: two-step and one-step processes. The two-step coal-to-natural gas technology belongs to the more traditional technology, and is a method for converting coal into synthesis gas (CO + H2) and performing methanation to obtain SNG, which needs to undergo the following steps: gasification, shift cooling, purification, methane synthesis, and the like. The one-step coal-to-natural gas technology is characterized in that coal is used as a raw material to directly synthesize methane, and gasification, transformation and methanation reaction processes are realized in a gasification furnace through a catalyst to obtain the synthesis gas rich in methane. The two-step coal-to-natural gas technology needs to be realized in different reactors, so that the temperature and the pressure in each reaction process are not matched, the heat loss is high during the internal circulation of the system, and the energy conversion efficiency of the system is reduced. The one-step coal-based natural gas technology effectively solves the problems, realizes the coupling of material flow and heat, and has higher economical efficiency and feasibility, thereby becoming an important research direction in the field of coal-based natural gas.
US patent 4077778 proposes a process for preparing methane by coal one-step method, which uses alkali metal carbonate or alkali metal hydroxide as catalyst, controls the reaction temperature in the furnace at about 700 ℃ by superheated steam, and reacts with coal powder under the action of catalyst to directly obtain methane-rich gas. The process needs to heat superheated steam to about 850 ℃, has high energy consumption and low carbon conversion rate, is difficult to maintain the reaction temperature under the condition of no external heat supply, and is still in the research and development stage.
Chinese patent CN102021037B proposes a method for producing methane by coal catalytic gasification in one step, which is to divide a gasification furnace into a synthesis gas generation section, a coal methanation section and a synthesis gas methanation section, so that the combustion, gasification, methanation and pyrolysis reactions are performed in stages. However, the gasification furnace needs to be provided with a plurality of layers of air distribution plates and overflow channels, the structure in the furnace is complex, the gasification efficiency and the methane yield are low, and the introduction of oxygen at the bottom of the fluidized bed is easy to melt and agglomerate ash slag to form large slag which blocks an outlet and a gas distributor of the gasification furnace, so that the operation stability of the device is affected and the technology is not provided with an industrialized device.
In summary, although the existing coal catalytic gasification technology solves the disadvantages of the traditional fixed bed and entrained flow gasification for preparing methane-rich synthesis gas to a certain extent, the existing coal catalytic gasification technology is in the research and development or amplification stage, and has not yet been applied industrially. Due to the limitations of fluidized bed technology and catalytic process conditions, carbon conversion and gasification intensity are low. Therefore, the key for the development of the coal gasification technology is how to effectively improve the carbon conversion rate and the gasification strength, effectively perform gradient utilization of heat of combustion, gasification and pyrolysis, reasonably couple reaction processes of combustion, gasification, pyrolysis, transformation, methanation and the like, and realize the true quality-based grading, high efficiency and clean utilization of the pyrolysis-gasification integrated pulverized coal.
Disclosure of Invention
The invention aims to provide a pulverized coal fluidized catalytic gasification device and a method for coupling pulverized coal pyrolysis, combustion and gasification, aiming at the problems of low carbon conversion rate and gasification strength, low methane yield, low pulverized coal utilization rate and difficult utilization of low-rank coal in the prior art. The invention has the characteristics of high carbon conversion rate, high gasification strength, high methane yield, high pulverized coal utilization rate, wide gasified coal type adaptability, reasonable energy utilization, and stable and efficient device operation.
According to an aspect of the present invention, there is provided an apparatus for fluidized catalytic gasification of pulverized coal, comprising:
a feeder;
the fast bed pyrolysis furnace is connected with the feeding machine through a feeding inclined pipe;
the fluidized bed gasification furnace is connected with the fast bed pyrolysis furnace;
the lower inlet of the fast bed gasification furnace is connected with the upper outlet of the fluidized bed gasification furnace;
the upper inlet of the fluidized bed combustion chamber is connected with the lower outlet of the fluidized bed gasification furnace;
a fine powder settling/stripping device connected with the fast bed pyrolysis furnace through a gasification inclined pipe.
According to some embodiments of the invention, the lower part of the side wall of the fast bed pyrolysis furnace is respectively provided with a pulverized coal inlet and a gasified semicoke inlet, and the pulverized coal inlet is connected with the feeding machine through a feeding inclined pipe; the gasification semicoke inlet is connected with the fine powder settling/stripping device through a gasification inclined pipe; the upper part of the fast bed pyrolysis furnace is provided with a pyrolysis product outlet which is connected with the fluidized bed gasification furnace.
According to a preferred embodiment of the present invention, a pyrolysis fluidization gas inlet is provided at the bottom of the fast bed pyrolysis furnace for receiving pyrolysis fluidization gas.
According to a preferred embodiment of the present invention, the fluidized-bed gasification furnace is arranged in parallel with the fast-bed pyrolysis furnace.
According to some embodiments of the present invention, the fluidized-bed gasification furnace is provided at an upper portion of a sidewall thereof with a pyrolysis product inlet, which is connected to the fast-bed pyrolysis furnace.
According to a preferred embodiment of the present invention, a gasifying agent inlet is provided at a lower portion of a sidewall of the fluidized-bed gasification furnace, and the gasifying agent inlet is configured to receive a gasifying agent.
According to a preferred embodiment of the present invention, a lower outlet of the fluidized-bed gasification furnace is connected to an upper inlet of the fluidized-bed combustion chamber.
According to some embodiments of the invention, a gas distribution plate is disposed below an interior of the fluidized bed combustor; and an ash residue discharge port is arranged at the bottom of the fluidized bed combustion chamber and is connected with an ash residue tank.
According to a preferred embodiment of the present invention, the upper outlet of the fluidized-bed gasification furnace is reduced in diameter and then connected to the lower inlet of the fast-bed gasification furnace.
According to a preferred embodiment of the present invention, the fast bed gasifier comprises, from bottom to top, a fast bed gasification/cracking zone, a fast bed steam shift zone and a fast bed methanation zone; preferably, a steam inlet is arranged on the side wall of the fast bed steam shift zone, and a synthesis gas return port is arranged on the side wall of the fast bed methanation zone.
According to some embodiments of the invention, the fines settling/stripper comprises a stripping section, a fines settling section, and a fines settling/stripper cyclone; a stripping gas inlet is formed in the lower part of the side wall of the fine powder settling/stripping device and used for receiving stripping gas; a semicoke outlet is arranged at the lower part of the side wall of the fine powder settling/stripping device and is connected with the fast bed pyrolysis furnace through a gasification inclined pipe; the top of the fine powder settling/stripping device is provided with a synthesis gas outlet which is connected with a gas outlet of the cyclone separator of the fine powder settling/stripping device and used for discharging the separated synthesis gas.
According to a preferred embodiment of the present invention, a fast bed cyclone is provided inside the fine powder settling/stripping vessel, which is connected to an upper outlet of the fast bed gasification furnace.
According to some embodiments of the invention, the apparatus further comprises an aftertreatment system comprising:
a gas-solid rapid separator connected with the synthesis gas outlet of the fine powder settling/stripping device;
and the gas separation device is connected with the gas-solid rapid separator.
According to a preferred embodiment of the present invention, the gas-solid rapid separator is provided with a synthesis gas inlet, a fly ash outlet and a gas-solid rapid separator gas outlet, the synthesis gas inlet is connected with the synthesis gas outlet of the fine powder sedimentation/stripping device, and the gas-solid rapid separator gas outlet is connected with a gas separation device.
According to a preferred embodiment of the invention, the gas separation device is provided with a gas inlet, a circulating gas outlet and a synthesis gas outlet, the gas inlet is connected with the gas outlet of the gas-solid rapid separator, and the circulating gas outlet is connected with the synthesis gas return port of the rapid bed methanation region.
According to some embodiments of the invention, the apparatus further comprises a catalyst system comprising a catalyst recovery unit and a catalyst loading unit; the upstream of the catalyst recovery device is connected with the ash tank, and the downstream of the catalyst recovery device is connected with the catalyst loading device; the upstream of the catalyst loading device is connected with the catalyst recovery device, and the downstream of the catalyst loading device is connected with the feeder.
According to a preferred embodiment of the invention, the catalyst recovery unit is provided with an inlet connected to a ash tank, an ash outlet connected to the catalyst loading unit and a catalyst outlet.
According to a preferred embodiment of the present invention, the catalyst loading device is provided with a first catalyst inlet, a second catalyst inlet, a carrier inlet and a catalyst outlet, the first catalyst inlet is connected with the catalyst outlet of the catalyst recovery device, the second catalyst inlet is used for replenishing the catalyst, the carrier inlet is used for adding the carrier, and the catalyst outlet is connected with the feeding machine.
According to a preferred embodiment of the invention, a gasification semicoke return valve is arranged on the gasification inclined tube, and is a non-mechanical return valve, preferably a U valve, a J valve, an L valve or an M valve. And (3) introducing loosening gas into the gasification semicoke return valve, and controlling the circulation quantity of the gasification semicoke, or the material level of the fine powder sedimentation/stripping device, or the temperature of the fast bed pyrolysis furnace by adjusting the air quantity of the loosening gas.
According to another aspect of the present invention, there is provided a method for fluidized catalytic gasification of pulverized coal, which employs the above apparatus, comprising the steps of:
(a) feeding the pulverized coal raw material into a fast bed pyrolysis furnace by a feeder, mixing the pulverized coal raw material with high-temperature gasification semicoke in the fast bed pyrolysis furnace and heating, and carrying out pyrolysis reaction on the pulverized coal to generate a pyrolysis product containing pyrolysis semicoke and pyrolysis gas;
(b) the pyrolysis product enters a fluidized bed gasification furnace, contacts with a gasification agent, and generates gasification reaction and tar cracking reaction in the fluidized bed gasification furnace and the fast bed gasification furnace to generate synthesis gas and carbon-containing gasification semi-coke;
(c) the synthesis gas enters a fine powder settling/stripping device, high-temperature gasification semi-coke is separated, and the high-temperature gasification semi-coke enters a fast bed pyrolysis furnace through a gasification inclined tube;
(d) the carbon-containing gasified semicoke enters the fluidized bed combustion chamber from the fluidized bed gasification furnace downwards to generate combustion reaction to produce ash and high-temperature gas; the high-temperature gas upwards enters the fluidized bed gasification furnace as a gasification agent.
According to some embodiments of the invention, the pulverized coal feedstock comprises pulverized coal and at least one of a catalyst and biomass; preferably, the catalyst comprises at least one of an alkali metal, an alkaline earth metal, and a transition metal.
According to the preferred embodiment of the invention, the catalyst is loaded on the pulverized coal by an impregnation method, a dry mixing method, an ion exchange method or the like, and the loading amount of the catalyst accounts for 0.1-30% of the mass of the pulverized coal.
According to the preferred embodiment of the invention, the pyrolysis pressure of the fast bed pyrolysis furnace is 0-6.5MPa, and the pyrolysis temperature is 400-800 ℃; and/or the pulverized coal in the dense phase zone of the fast bed pyrolysis furnace has the average density of 200-550kg/m3The linear speed of the empty tower is 0.1-1.0 m/s.
According to a preferred embodiment of the present invention, the pyrolysis fluidization gas is introduced into the fast bed pyrolysis furnace through a pyrolysis fluidization gas inlet at the bottom thereof; the pyrolysis fluidizing gas comprises water vapor and CO2At least one of CO and an inert gas.
According to some embodiments of the present invention, the pyrolysis product enters the upper portion of the fluidized-bed gasification furnace, contacts with the gasification agent, and undergoes gasification reaction and tar cracking reaction in the fluidized-bed gasification furnace and the fast-bed gasification furnace to generate synthesis gas and carbon-containing gasification semicoke. While the fast bed gasification furnace generates gasification reaction, steam is introduced into the fast bed steam shift zone to generate steam reaction (CO + H)2O＝CO2+H2) Adjusting H2The ratio of/CO; introducing the circulating synthesis gas into the methanation region of the fast bed to perform methanation reaction (CO + 3H)2＝CH4+H2O) to increase the yield of methane in the product.
According toIn a preferred embodiment of the invention, the gasifying agent is high-temperature gas from a fluidized bed combustion chamber or externally introduced gasifying agent through a gasifying agent inlet; the gasifying agent comprises steam and/or CO2。
According to the preferred embodiment of the present invention, the gasification pressure of the fluidized bed gasification furnace is 0-6.5MPa, the gasification temperature is 700-1200 ℃, and the average density of the pulverized coal is 200-450kg/m3The average superficial linear velocity is 0.2-1.2 m/s.
According to the preferred embodiment of the invention, the gasification pressure of the fast bed gasification/pyrolysis zone is 0-6.5MPa, and the gasification temperature is 700-1200 ℃; and/or the gasification pressure of the fast bed steam transformation zone is 0-6.5MPa, and the gasification temperature is 700-1000 ℃; and/or the gasification pressure of the methanation region of the fast bed is 0-6.5MPa, and the gasification temperature is 700-900 ℃; and/or the average density of the pulverized coal in the rapid bed gasification furnace is 50-150 kg/m3The average superficial linear velocity is 1.0-3.0 m/s.
According to some embodiments of the invention, the synthesis gas from the fast bed gasifier, which carries the non-gasified fine semi-coke powder, first enters the fast bed cyclone separator for preliminary gas-solid separation, the solid falls into the stripping section of the fine powder settling/stripping device, and the gas enters the settling section of the fine powder settling/stripping device.
According to the preferred embodiment of the invention, the gas from the fast bed cyclone separator enters the settling section of the fine powder settling/stripping device and the cyclone separator of the fine powder settling/stripping device to further separate out solids, the solids fall into the stripping section of the fine powder settling/stripping device, and the gas leaves the fine powder settling/stripping device and enters the gas-solid fast separator to be separated and remove fly ash, and then enters the gas separation device; the gas separation device separates methane from the synthesis gas and divides the methane into recycle gas (methane-poor gas) and methane-rich synthesis gas; a part of the gas from the gas separation unit is recycled to the fast bed methanation region, and the other part is discharged as methane-rich synthesis gas.
According to the preferred embodiment of the invention, stripping gas is introduced into the stripping section of the fine powder settling/stripping device through a stripping gas inlet, the solids in the stripping section are stripped, fly ash entrained in the solids is removed, and high-temperature gasification semicoke is obtained and enters the fast bed pyrolysis furnace through the gasification inclined tube.
According to a preferred embodiment of the invention, the stripping gas comprises steam, CO2At least one of CO and an inert gas.
According to the preferred embodiment of the invention, the loosening gas is introduced into the gasification semicoke return valve, and the circulation quantity of the gasification semicoke, or the material level of the fine powder settling/stripping device, or the temperature of the fast bed pyrolysis furnace is controlled by adjusting the air quantity of the loosening gas.
According to a preferred embodiment of the invention, the loosening gas comprises water vapour, CO2At least one of CO, air, oxygen, and an inert gas.
According to the preferred embodiment of the invention, the pressure of the fine powder settling/stripping device is 0-6.5MPa, the temperature is 700-1200 ℃, and the average density of the fine powder is 350-550kg/m3The average superficial linear velocity is 0.1-0.5 m/s.
According to some embodiments of the invention, the carbon-containing gasification semicoke enters the fluidized bed combustion chamber from the fluidized bed gasification furnace downwards, and is contacted with the oxidant to perform a combustion reaction to produce ash and high-temperature gas; the high-temperature gas upwards enters the fluidized bed gasification furnace to be used as a gasification agent and provides heat for gasification reaction; the ash and slag are discharged to an ash and slag tank through an ash and slag discharge port and then enter a catalyst recovery device to separate out a catalyst and the ash and slag, the recovered catalyst enters a catalyst loading device and is loaded on a carrier and then is conveyed to a feeder as a raw material.
According to a preferred embodiment of the invention, the oxidant comprises air and/or oxygen.
According to a preferred embodiment of the invention, the carrier comprises pulverized coal, coke and other carbonaceous material.
According to a preferred embodiment of the present invention, the catalyst and/or biomass may also be replenished through the second catalyst inlet of the catalyst support.
According to a preferred embodiment of the invention, the combustion of the fluidized bed combustorThe burning pressure is 0-6.5MPa, the burning temperature is 800-1500 ℃, and the average density of the pulverized coal is 300-450kg/m3The average superficial linear velocity is 0.2-0.6 m/s.
The technical scheme of the invention is that the pyrolysis of the pulverized coal raw material is carried out in the pyrolysis furnace to obtain pyrolysis gas (containing coal tar) and gasification raw material-pyrolysis semicoke, and the gasification raw material is obtained through pyrolysis, thereby expanding the application range of coal types. And carrying out gasification reaction of pyrolysis semicoke particles, cracking of coal tar and other reactions in the gasification furnace to generate synthesis gas. And most of the high-temperature gasified semicoke particles which are not gasified are used as heat carriers and circularly enter the pyrolysis furnace to be used as a heat source for pyrolysis, so that the energy consumption is reduced, and the cost of the heat carriers added in the traditional process is saved. A small part of gasified semicoke particles which are not gasified enter the combustion chamber to be subjected to combustion reaction with oxygen, and semicoke is converted into ash, so that the carbon conversion rate and the utilization rate of carbon residue are improved. The heat generated by the combustion reaction is used to provide heat consumption and heat rejection in the gasification reaction and to provide the necessary gasification agent for the gasification reaction. The invention is specially provided with a fine powder sedimentation/stripping device, and aims to remove fly ash entrained in high-temperature gasification semi-coke entering a pyrolysis furnace, thereby reducing the fly ash entrained in pyrolysis gas and avoiding the blockage of related equipment by the fly ash.
The invention couples the processes of pyrolysis and gasification, gasification and combustion, gasification and transformation, methanation and the like, realizes the partition coupling of gasification, transformation, methanation and tar cracking in one gasifier, and effectively improves the methane yield of one-way reaction; the separated synthesis gas is circularly returned to a methanation region of the gasification furnace for further methanation reaction, so that the synthesis gas rich in methane can be produced, coal tar is byproduct, and the quality-based graded utilization of low-rank coal is realized. The direct gasification or catalytic gasification of the pulverized coal can be carried out, and the catalyst is recycled after being separated and recovered, so that the high-efficiency, clean and reasonable comprehensive utilization of the coal is realized.
Compared with the prior art, the method has the advantages that the carbon conversion rate of the gasification outlet in the reactor is improved to 98%, the methane content in the synthesis gas is improved to 25%, the yield of the tar is increased by 10%, the method has the characteristics of high carbon conversion rate, high methane yield, high yield of the tar and high utilization rate of the pulverized coal, and a good technical effect is achieved.
Drawings
FIG. 1 is a schematic diagram of a pulverized coal fluidized catalytic gasification apparatus according to the present invention:
in fig. 1, 1 is a feeder; 2 is a feeding inclined tube; 3 is a fast bed pyrolysis furnace; 4 is a fluidized bed combustion chamber; 5 is a fluidized bed gasification furnace; 6 is a fast bed gasification furnace; 7 is a fast bed gasification/cracking zone; 8 is a fast bed steam shift zone; 9 is a fast bed methanation region; 10 is a fine powder settling/stripping device; 11 is a cyclone separator of a fast bed gasification furnace; 12 is a stripping section; 13 is a fine powder settling section; 14 is a fine powder settling/stripping cyclone separator; 15 is a gas distribution plate; 16 is a clinker outlet; 17 is a slag tank; 18 is a gasification inclined tube; 19 is a gasification semicoke return valve; 20 is a gas-solid rapid separator; 21 is a gas separation device; 22 is a catalyst recovery device; 23 is a pulverized coal catalyst loading device; a is a pulverized coal raw material; b is pyrolysis fluidization gas; c is an oxidant; d is a gasifying agent; e is water vapor; f is stripping gas; G. h is loosening air; i is fly ash; j is methane-rich syngas; k is ash; m is a carrier; n is a catalyst and/or biomass.
Detailed Description
The present invention will be further illustrated by the following examples, but is not limited to these examples.
In the following examples, the evaluation and testing methods involved are as follows:
the carbon conversion rate is calculated based on the carbon residue in the ash, and the specific formula is as follows:
CC＝(1-Cash/Craw) X 100%, where CC is carbon conversion, CashIs the carbon content in the ash, CrawIs the carbon content in the powdered coal raw material;
measuring gas components by an external standard method of an online gas chromatograph, and measuring the content of methane in the synthesis gas;
the yield of tar is calculated by the mass balance of gas, liquid and solid products, and the specific formula is as follows: y istar＝(Mraw-Mgas-Mash)/MrawX 100% where YtarFor tar yield, MrawIs the mass flow of the powdered coal raw material，MgasIs the product gas mass flow, MashIs the ash mass flow.
[ example 1 ]
The reaction process is as follows: the raw materials are sent into a fast bed pyrolysis furnace (3) by a feeder (1), and are mixed with high-temperature gasification semicoke/ash slag from a gasification furnace to be heated, so that pyrolysis reaction is carried out, and pyrolysis gas and pyrolysis semicoke enter a fluidized bed gasification furnace (5). Wherein, the pyrolysis semicoke is contacted with a gasifying agent D, and gasification reaction and tar cracking reaction are carried out in a fluidized bed gasification furnace (5) and a fast bed gasification furnace (6) to generate synthesis gas. While the fast bed gasification furnace (6) generates gasification reaction, the water vapor E is introduced into the fast bed water vapor shift zone (8) to generate water vapor shift reaction to adjust H2The ratio of/CO is that the circulating synthesis gas is introduced into the fast bed methanation region (9) to perform methanation reaction to improve the yield of methane in the product. The synthesis gas separated from the synthesis gas with the semi-coke fine powder enters a subsequent gas-solid rapid separator (20) to remove fly ash I, and partial synthesis gas in the synthesis gas is used as circulating gas to circulate to a rapid bed methanation region (9) for further methanation reaction, so that the yield of methane is improved. Fines recovered from the fines settling/stripper cyclone (14) fall through the dipleg into the stripping section (12). The stripping section (12) adopts stripping gas F to strip unreacted carbon-containing semicoke and ash, the carbon-containing semicoke and ash compounds after stripping enter the fast bed pyrolysis furnace (3) to be mixed with fresh pulverized coal after controlling the circulation quantity, and the fresh pulverized coal is heated to carry out pyrolysis. The carbon-containing gasified semicoke and ash fall into a fluidized bed combustion chamber (4) from the bottom of the fluidized bed gasification furnace (5) to be contacted and mixed with an oxidant C for combustion reaction, and the ash is discharged out of the device periodically or continuously. High-temperature gas generated by combustion enters the fluidized bed gasification furnace (5) upwards to be used as a gasification agent and provides heat for a gasification medium. The catalyst-containing ash discharged from the ash tank (17) enters a catalyst recovery device (22) to recover the catalyst after heat exchange, and then is discharged, and the recovered catalyst enters a catalyst loading device (23) to be recycled.
Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 400 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 200 kg/m3Fast bed pyrolysis furnace(3) The linear speed of the internal hollow tower is 1.0 m/s; the gasification pressure and the gasification temperature of the fluidized bed gasification furnace (5) are 0 and 700 ℃, and the average density of the pulverized coal is 200 kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 1.2 m/s; the gasification pressure and the gasification temperature of the fast bed gasification/pyrolysis zone (7) are 0 and 700 ℃; the gasification pressure and the gasification temperature of the fast bed steam transformation area (8) are 0 and 700 ℃; the gasification pressure and the gasification temperature of the fast bed methanation region (9) are 0 and 700 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 50kg/m3The average superficial linear velocity is 3.0 m/s; the combustion pressure and the combustion temperature of the fluidized bed combustion chamber (4) are 0 ℃ and 800 ℃, and the average density of the pulverized coal is 300 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.6 m/s; the pressure of the fine powder sedimentation/stripping device (10) is 0, the temperature is 700 ℃, and the average density of the fine powder is 350 kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.5 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. By adopting the scheme, the carbon conversion rate at the gasification outlet in the reactor is 93%, the methane content in the synthesis gas is increased to 16.7%, and the tar yield is 8.2%. The detailed results are shown in Table 1.
[ example 2 ]
The reaction scheme is the same as in example 1. Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 400 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 200 kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 1.0 m/s; the gasification pressure and the gasification temperature of the fluidized bed gasification furnace (5) are 0 and 700 ℃, and the average density of the pulverized coal is 200 kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 1.2 m/s; the gasification pressure and the gasification temperature of the fast bed gasification/pyrolysis zone (7) are 0 and 700 ℃; the gasification pressure and the gasification temperature of the fast bed steam transformation area (8) are 0 and 700 ℃; the gasification pressure and the gasification temperature of the fast bed methanation region (9) are 0 and 700 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 50kg/m3The average superficial linear velocity is 3.0 m/s; the combustion pressure and the combustion temperature of the fluidized bed combustion chamber (4) are 0 ℃ and 800 ℃, and the average density of the pulverized coal is 300 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.6 m/s; the pressure of the fine powder settling/stripping device (10) is 0,The temperature is 700 ℃, and the average density of the pulverized coal is 350 kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.5 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. Through the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 93%, the content of methane in the synthesis gas is increased to 17.3%, and the yield of tar is 7.8%. The detailed results are shown in Table 1.
[ example 3 ]
The reaction scheme is the same as in example 1. Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 800 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 200 kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 1.0 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 0, the gasification temperature is 1200 ℃, and the average density of the pulverized coal is 200 kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 1.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 0, and the gasification temperature is 1200 ℃; the gasification pressure and the gasification temperature of the fast bed steam conversion zone (8) are 0 ℃ and 1000 ℃; the gasification pressure and the gasification temperature of the methanation region (9) of the fast bed are 0 and 900 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 50kg/m3The average superficial linear velocity is 3.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 0, the combustion temperature is 1500 ℃, and the average density of the pulverized coal is 300 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.6 m/s; the pressure of the fine powder sedimentation/stripping device (10) is 0, the temperature is 1200 ℃, and the average density of the fine powder is 350 kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.5 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. Through the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 96%, the content of methane in the synthesis gas is increased to 20.8%, and the yield of tar is 5.8%. The detailed results are shown in Table 1.
[ example 4 ]
The reaction scheme is the same as in example 1. Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 800 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 200 kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 1.0 m/s;the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 1200 ℃, and the average density of the pulverized coal is 200 kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 1.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 1200 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 1000 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 900 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 50kg/m3The average superficial linear velocity is 3.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1500 ℃, and the average density of the pulverized coal is 300 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.6 m/s; the pressure of the fine powder sedimentation/stripping device (10) is 6.5MPa, the temperature is 1200 ℃, and the average density of the fine powder is 350 kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.5 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. Through the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 96%, the content of methane in the synthesis gas is increased to 22.3%, and the yield of tar is 5.3%. The detailed results are shown in Table 1.
[ example 5 ]
The reaction scheme is the same as in example 1. Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 800 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 1200 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 1200 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 1000 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 900 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1500 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; thin and thinThe pressure of the powder sedimentation/stripping device (10) is 6.5MPa, the temperature is 1200 ℃, and the average density of the pulverized coal is 550kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.1 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. By the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 96%, the content of methane in the synthesis gas is increased to 22.9%, and the yield of tar is increased by 5.2%. The detailed results are shown in Table 1.
[ example 6 ]
The reaction scheme is the same as in example 1. Lignite is adopted as a raw material in the reaction flow. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 600 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 900 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 900 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 850 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 800 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1100 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; the pressure of the fine powder settling/stripping device (10) is 6.5MPa, the temperature is 900 ℃, and the average density of the fine powder is 550kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.1 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. By the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 95%, the content of methane in the synthesis gas is increased to 23.6%, and the yield of tar is increased by 9.9%. The detailed results are shown in Table 1.
[ example 7 ]
The reaction scheme is the same as in example 1. The raw materials in the reaction process adopt brown coal and 5 percent of K2CO3. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 600 ℃, (fast bed pyrolysis furnace:3) average density of pulverized coal 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 900 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 900 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 850 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 800 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1100 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; the pressure of the fine powder settling/stripping device (10) is 6.5MPa, the temperature is 900 ℃, and the average density of the fine powder is 550kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.1 m/s. Wherein the pyrolysis fluidization gas B adopts inert gas, and the gasifying agent D adopts water vapor. By the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 98%, the content of methane in the synthesis gas is increased to 24.8%, and the yield of tar is increased by 8.7%. The detailed results are shown in Table 1.
[ example 8 ]
The reaction scheme is the same as in example 1. The raw materials in the reaction process adopt brown coal and 5 percent of K2CO3. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 600 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 900 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 900 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 850 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 800 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, and combustion is performedThe temperature is 1100 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; the pressure of the fine powder settling/stripping device (10) is 6.5MPa, the temperature is 900 ℃, and the average density of the fine powder is 550kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.1 m/s. Wherein, the pyrolysis fluidization gas B adopts hydrogen, and the gasification agent D adopts steam. By the scheme, the conversion rate of the carbon at the gasification outlet in the reactor is 98%, the content of methane in the synthesis gas is increased to 25.0%, and the yield of tar is increased by 8.1%. The detailed results are shown in Table 1.
[ example 9 ]
The reaction scheme is the same as in example 1. The raw materials in the reaction process adopt brown coal and 5 percent of K2CO3. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 600 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 900 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 900 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 850 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 800 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1100 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; the pressure of the fine powder settling/stripping device (10) is 6.5MPa, the temperature is 900 ℃, and the average density of the fine powder is 550kg/m3The mean superficial velocity in the fine powder settler/stripper (10) was 0.1 m/s. Wherein the pyrolysis fluidized gas B adopts inert atmosphere, and the gasifying agent D adopts CO2. By the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 98%, the content of methane in the synthesis gas is increased to 24.7%, and the yield of tar is increased by 8.7%. The detailed results are shown in Table 1.
[ COMPARATIVE EXAMPLE 1 ]
The reaction scheme is the same as in example 1.The raw materials in the reaction process adopt brown coal and 5 percent of K2CO3. The pyrolysis pressure and the pyrolysis temperature of the fast bed pyrolysis furnace (3) are 0 ℃ and 600 ℃, and the average density of the pulverized coal of the fast bed pyrolysis furnace (3) is 550kg/m3The linear speed of an empty tower in the fast bed pyrolysis furnace (3) is 0.1 m/s; the gasification pressure of the fluidized bed gasification furnace (5) is 6.5MPa, the gasification temperature is 900 ℃, and the average density of the pulverized coal is 450kg/m3The linear speed of an average empty tower in the fluidized bed gasification furnace (8) is 0.2 m/s; the gasification pressure of the fast bed gasification/pyrolysis zone (7) is 6.5MPa, and the gasification temperature is 900 ℃; the gasification pressure of the fast bed steam conversion zone (8) is 6.5MPa, and the gasification temperature is 850 ℃; the gasification pressure of the fast bed methanation region (9) is 6.5MPa, and the gasification temperature is 800 ℃; the average density of the pulverized coal in the fast bed gasification furnace (6) is 150kg/m3The average superficial linear velocity is 1.0 m/s; the combustion pressure of the fluidized bed combustion chamber (4) is 6.5MPa, the combustion temperature is 1100 ℃, and the average density of the pulverized coal is 500 kg/m3The linear speed of the average empty tower in the fluidized bed combustion chamber (4) is 0.2 m/s; the fines settler/stripper (10) is not provided and is replaced by a cyclone separator only. The pyrolysis fluidization gas B adopts inert atmosphere; the gasifying agent D adopts steam. Through the scheme, the conversion rate of carbon at the gasification outlet in the reactor is 90%, the content of methane in the synthesis gas is increased to 19.5%, and the yield of tar is 7.9%. The detailed results are shown in Table 1.
[ COMPARATIVE EXAMPLE 2 ]
The method is characterized in that a new ao group PDU gasification reaction device in the prior art (see Bishencheng, catalytic gasification (one-step method) development progress of coal-based natural gas technology [ C ]. fourth economic workshop on coal-based synthetic natural gas technology, 2013, Wuluqi) is adopted, lignite is adopted as a raw material, 10% potassium carbonate is added as a catalyst, the linear speed is less than 10m/s, the operating temperature is 800 ℃, the methane content in an outlet gas component obtained by gasification is 14%, the carbon conversion rate is 90%, no tar product is generated, and the result is detailed in Table 1.
[ COMPARATIVE EXAMPLE 3 ]
By adopting a traditional lurgi furnace pressurized fixed bed gasification device in the prior art (see Roc and the like, development and application of lurgi coal gasification technology [ J ]. clean coal technology, 2009,15 (5): 48-51), raw material lignite is gasified at 850 ℃, the methane content in the gas components at the outlet is 8.3%, the tar yield is 9%, the carbon conversion rate is only 90%, and the results are detailed in Table 1.
TABLE 1
Figure BDA0002213278910000151
Figure BDA0002213278910000161
Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims (16)

1. An apparatus for fluidized catalytic gasification of pulverized coal, comprising:
a feeder;
the fast bed pyrolysis furnace is connected with the feeding machine through a feeding inclined pipe;
the fluidized bed gasification furnace is connected with the fast bed pyrolysis furnace;
the lower inlet of the fast bed gasification furnace is connected with the upper outlet of the fluidized bed gasification furnace;
the upper inlet of the fluidized bed combustion chamber is connected with the lower outlet of the fluidized bed gasification furnace;
a fine powder settling/stripping device connected with the fast bed pyrolysis furnace through a gasification inclined pipe.
2. The device of claim 1, wherein a pulverized coal inlet and a gasified semicoke inlet are respectively arranged at the lower part of the side wall of the fast bed pyrolysis furnace, and the pulverized coal inlet is connected with the feeding machine through a feeding inclined pipe; the gasification semicoke inlet is connected with the fine powder settling/stripping device through a gasification inclined pipe; the upper part of the fast bed pyrolysis furnace is provided with an outlet which is connected with the fluidized bed gasification furnace; preferably, a pyrolysis fluidization gas inlet is arranged at the bottom of the fast bed pyrolysis furnace and used for receiving pyrolysis fluidization gas.
3. The apparatus as claimed in claim 1 or 2, wherein a pyrolysis product inlet is provided at an upper portion of a sidewall of the fluidized-bed gasification furnace, and is connected to an outlet of the fast-bed pyrolysis furnace; preferably, a gasifying agent inlet is arranged at the lower part of the side wall of the fluidized bed gasification furnace and is used for receiving a gasifying agent; and/or an ash discharging port is arranged at the bottom of the fluidized bed combustion chamber and is connected with an ash tank.
4. The apparatus according to any one of claims 1 to 3, wherein the fast bed gasifier comprises from bottom to top a fast bed gasification/cracking zone, a fast bed steam shift zone and a fast bed methanation zone; preferably, a steam inlet is arranged on the side wall of the fast bed steam shift zone, and a synthesis gas return port is arranged on the side wall of the fast bed methanation zone.
5. The apparatus of any one of claims 1-4, wherein the fines settler/stripper comprises a stripping section, a fines settler section, and a fines settler/stripper cyclone; a stripping gas inlet is formed in the lower part of the side wall of the fine powder settling/stripping device and used for receiving stripping gas; a semicoke outlet is arranged at the lower part of the side wall of the fine powder settling/stripping device and is connected with the fast bed pyrolysis furnace through a gasification inclined pipe; the top of the fine powder settling/stripping device is provided with a synthesis gas outlet which is connected with a gas outlet of a cyclone separator of the fine powder settling/stripping device and used for discharging synthesis gas; and/or a fast bed cyclone separator is arranged in the fine powder settling/stripping device and is connected with the upper outlet of the fast bed gasification furnace.
6. The apparatus of any one of claims 1-5, further comprising an aftertreatment system comprising:
a gas-solid rapid separator connected with the synthesis gas outlet of the fine powder settling/stripping device;
and the gas separation device is connected with the gas-solid rapid separator.
7. The apparatus of any one of claims 1-6, further comprising a catalyst system comprising a catalyst recovery device and a catalyst loading device; the upstream of the catalyst recovery device is connected with the ash tank, and the downstream of the catalyst recovery device is connected with the catalyst loading device; the upstream of the catalyst loading device is connected with the catalyst recovery device, and the downstream of the catalyst loading device is connected with the feeder.
8. A method for fluidized catalytic gasification of pulverized coal using the apparatus of any one of claims 1 to 7, comprising the steps of:
(a) feeding the pulverized coal raw material into a fast bed pyrolysis furnace by a feeder, mixing the pulverized coal raw material with high-temperature gasification semicoke in the fast bed pyrolysis furnace and heating, and carrying out pyrolysis reaction on the pulverized coal to generate a pyrolysis product containing pyrolysis semicoke and pyrolysis gas;
(b) the pyrolysis product enters a fluidized bed gasification furnace, contacts with a gasification agent, and generates gasification reaction and tar cracking reaction in the fluidized bed gasification furnace and the fast bed gasification furnace to generate synthesis gas and carbon-containing gasification semi-coke;
(c) the synthesis gas enters a fine powder settling/stripping device, high-temperature gasification semi-coke is separated, and the high-temperature gasification semi-coke enters a fast bed pyrolysis furnace through a gasification inclined tube;
(d) the carbon-containing gasified semicoke enters the fluidized bed combustion chamber from the fluidized bed gasification furnace downwards to generate combustion reaction to produce ash and high-temperature gas; the high-temperature gas upwards enters the fluidized bed gasification furnace as a gasification agent.
9. The method of claim 8, wherein the pulverized coal feed comprises pulverized coal and at least one of a catalyst and biomass; preferably, the catalyst comprises at least one of an alkali metal, an alkaline earth metal, and a transition metal.
10. The method as claimed in claim 8 or 9, wherein the pyrolysis pressure of the fast bed pyrolysis furnace is 0-6.5MPa, and the pyrolysis temperature is 400-800 ℃; and/or the pulverized coal in the dense phase zone of the fast bed pyrolysis furnace has the average density of 200-550kg/m3The linear speed of the empty tower is 0.1-1.0 m/s.
11. The method according to any one of claims 8 to 10, wherein the pyrolysis product enters the fluidized-bed gasification furnace, contacts with a gasification agent, and undergoes gasification reaction and tar cracking reaction in the fluidized-bed gasification furnace and the fast-bed gasification furnace to generate synthesis gas and carbon-containing gasification semicoke; introducing steam into the fast bed steam conversion area while the fast bed gasification furnace is in gasification reaction to generate steam reaction; and introducing the circulating synthesis gas into the fast bed methanation region to perform methanation reaction.
12. The method according to any of claims 8-11, wherein the fluidized bed is a fluidized bedThe gasification pressure of the gasification furnace is 0-6.5MPa, the gasification temperature is 700-3The average superficial linear velocity is 0.2-1.2 m/s; and/or the gasification pressure of the fast bed gasification/pyrolysis zone is 0-6.5MPa, and the gasification temperature is 700-1200 ℃; and/or the gasification pressure of the fast bed steam transformation zone is 0-6.5MPa, and the gasification temperature is 700-1000 ℃; and/or the gasification pressure of the methanation region of the fast bed is 0-6.5MPa, and the gasification temperature is 700-900 ℃; and/or the average density of the pulverized coal in the rapid bed gasification furnace is 50-150 kg/m3The average superficial linear velocity is 1.0-3.0 m/s.
13. The method as claimed in any one of claims 8 to 12, wherein the synthesis gas from the fast bed gasifier, which carries the semi-coke fine powder that is not gasified, first enters a fast bed cyclone separator for gas-solid separation, the solid falls into a stripping section of a fine powder settling/stripping device, and the gas enters a settling section of the fine powder settling/stripping device; and/or the gas from the fast bed cyclone separator enters a settling section of a fine powder settling/stripping device and a fine powder settling/stripping device cyclone separator to further separate out solids, the solids fall into a stripping section of the fine powder settling/stripping device, the gas leaves the fine powder settling/stripping device and enters a gas-solid fast separator to remove fly ash, and then the gas enters a gas separation device; and recycling part of the gas from the gas separation device to the fast bed methanation region.
14. The method according to any one of claims 8 to 13, characterized in that stripping gas is introduced into the stripping section of the fines settler/stripper to strip the solids in the stripping section and obtain high temperature gasification semicoke, which enters the fast bed pyrolysis furnace via gasification inclined tubes.
15. The method according to any one of claims 8 to 14, wherein the carbon-containing gasification semicoke enters the fluidized bed combustion chamber from the fluidized bed gasification furnace downwards, is contacted with the oxidant, and undergoes a combustion reaction to produce ash and high-temperature gas; the high-temperature gas upwards enters a fluidized bed gasification furnace to be used as a gasification agent; and discharging ash slag.
16. The method as claimed in any one of claims 8 to 15, wherein the pressure of the fine powder sedimentation/stripping device is 0-6.5MPa, the temperature is 700 ℃ and 1200 ℃, and the average density of the fine coal is 350 ℃ and 550kg/m3The average superficial linear velocity is 0.1-0.5 m/s; and/or the combustion pressure of the fluidized bed combustion chamber is 0-6.5MPa, the combustion temperature is 800-1500 ℃, and the average density of the pulverized coal is 300-450kg/m3The average superficial linear velocity is 0.2-0.6 m/s.
CN201910905967.7A 2019-09-24 2019-09-24 Device and method for fluidized catalytic gasification of pulverized coal Pending CN112625757A (en)

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