A composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking

Abstract

A composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking relates to the technical field of biomass gasification, and comprises a gasifier, a high-temperature cyclone cracking furnace, a heat recovery device, a cyclone separator, a high-temperature filter, a material sealing valve, a steam drum and an ash hopper; the gasifier comprises, from bottom to top, a slag discharge ring pipe, a gasifying agent nozzle, a gasifying furnace air chamber, a distribution plate, a fly ash return port II, a gasifier dense phase section, a biomass feed port, a fly ash return port I, a secondary gasifying agent nozzle and a gasifier dilute phase section, the slag discharge ring pipe is used to discharge ash in the bed layer of the gasifier dense phase section, and the gasifying agent nozzle is used to spray the gasifying agent into the bed layer of the gasifier dense phase section; the solid discharge port of the high-temperature cyclone cracking furnace is connected with the solid feed port of the material sealing valve, and the composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking can shorten the gasification reaction time, greatly improve the gasification intensity of the gasifier, and generate more combustible components.

Description

Technical field:

[0002] The invention relates to the technical field of biomass gasification, and in particular to a composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking. Background technology:

[0004] Since my country's energy structure is mainly based on fossil energy such as coal and oil, and the reserves of fossil fuels (coal, oil, natural gas) are limited, and the environmental problems caused by their use are becoming increasingly serious, there is an urgent need to develop clean renewable energy. Biomass energy, one of the renewable energy sources, is a clean energy that can be stored and transported. It has the advantages of wide resource distribution and large storage capacity, so it has huge development potential.

[0005] Biomass gasification technology is a thermochemical treatment technology. Its basic principle is to put solid biomass into a gasifier for incomplete combustion. During the conversion process, gasifying agents such as oxygen or water vapor need to be added to cause partial oxidation reaction, combustion, and gasification. Due to the special physical properties of solid biomass raw materials, solid biomass raw materials need to be pre-treated by crushing and adding media before entering the gasifier for gasification. The pretreated raw materials are burned in the gasifier, and the heat generated is used to maintain pyrolysis and reduction reactions, and finally a combustible mixed gas is obtained. After filtering the gas to remove tar and impurities, it can be used for combustion, power generation, gas production, or further synthesis of chemical products.

[0006] The patent application with application number 201110094281.8 and publication number CN102206514A involves a two-stage biomass cyclone high-temperature cracking gasifier. The gasifier consists of an upper cyclone high-temperature thermal cracking gasification chamber, a lower steam spraying pyrolysis gasification chamber, a screw feeder, a biomass gas discharge pipe, a gas fuel high-speed burner, and an ash box. The gasifier can greatly reduce the tar content in the produced biomass gas, but the high-temperature (above 1600°C) anaerobic flue gas produced by the gas fuel high-speed burner will consume a large amount of fuel gas produced in the biomass gasification process, that is, the gas production per unit biomass consumption is greatly reduced. At the same time, in order to form a strong cyclone vortex, the high-temperature flue gas is sprayed into the cyclone cracking gasification chamber at a high speed of >80m / s along the cyclone tangent and close to the inner wall of the cyclone cracking gasification chamber. Under this operating condition, the high-temperature flue gas and the biomass particles entrained therein will severely erode the inner wall of the cyclone. Summary of the invention:

[0008] In order to solve the above technical problems, the present invention provides a composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking.

[0009] The present invention is achieved through the following technical solutions:

[0010] A composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking, characterized in that it comprises a gasifier, a high-temperature cyclone cracking furnace, a heat recovery device, a cyclone separator, a high-temperature filter, a material sealing valve, a steam drum and an ash hopper; the gasifier comprises, from bottom to top, a slag discharge ring pipe, a gasifying agent nozzle, a gasifying furnace air chamber, a distribution plate, a fly ash return port II, a gasifier dense phase section, a biomass feed port, a fly ash return port I, a secondary gasifying agent nozzle and a gasifier dilute phase section, the slag discharge ring pipe is used to discharge the gasifier dense phase section bed The ash in the layer is discharged from the gasifier, and the gasifying agent nozzle is used to spray the gasifying agent into the dense phase section bed layer of the gasifier; the solid discharge port of the high-temperature cyclone cracking furnace is connected with the solid feed port of the material sealing valve, and the solid discharge port of the material sealing valve is connected with the dense phase section bed layer of the gasifier through the fly ash return port I, the bottom outlet of the lower cone section of the cyclone separator is connected with the top feed port of the ash hopper, and the bottom discharge port of the ash hopper is connected with the dense phase section bed layer of the gasifier through the fly ash return port II, and the solid discharge port of the high-temperature filter is connected with the fly ash return port II. The ash return port II is connected to the dense phase bed of the gasifier, the biomass feed port is located above the distribution plate, the secondary gasification agent nozzle is located above the dense phase bed of the gasifier, the top outlet of the gasifier is connected to the crude synthesis gas inlet of the high-temperature cyclone cracking furnace, and a gasification agent feed port is provided on the opposite side of the crude synthesis gas inlet of the high-temperature cyclone cracking furnace. The top gas-solid phase outlet of the high-temperature cyclone cracking furnace is connected to the heat recovery device, and the water / steam side of the heat recovery device is connected to the steam drum; the saturated water outlet at the bottom of the steam drum is connected to the saturated water inlet of the heat recovery device, the top saturated water / steam outlet on the water / steam side of the heat recovery device is connected to the saturated water / steam inlet at the bottom of the steam drum, the saturated steam outlet at the top of the steam drum is connected to the saturated steam inlet of the heat recovery device, and the superheated steam outlet of the heat recovery device is respectively connected to the gasification agent inlet of the cyclone cracking furnace and the gasification agent inlet of the gasification furnace gas chamber and the gasification agent nozzle of the gasifier; the bottom of the heat recovery device is connected to the gas-solid phase inlet of the cyclone separator, and the top outlet of the cyclone separator is connected to the crude synthesis gas inlet of the high-temperature filter.

[0011] In another aspect of the present invention, the heat recovery device is used to partially recover the sensible heat of the high-temperature dusty raw synthesis gas and produce superheated steam as a by-product.

[0012] In another aspect of the present invention, the cyclone separator is used to further separate part of the solid particles in the dusty raw synthesis gas.

[0013] In another aspect of the present invention, the high temperature filter is used to further filter out the semi-coke fly ash particles in the dusty raw synthesis gas that cannot be separated by the cyclone separator, and the semi-coke fly ash particles filtered out by the high temperature filter fall into the bottom cone section of the high temperature filter.

[0014] In another aspect of the present invention, the filter element of the high temperature filter is a metal filter element or a ceramic filter element.

[0015] In another aspect of the present invention, the height of the bed of the dense phase section of the gasifier is adjusted by controlling the slag discharge rate; there is a central high-temperature zone in the bed of the dense phase section of the gasifier, and a gasifying agent containing a certain oxygen concentration is sprayed into the central high-temperature zone through a gasifying agent nozzle to maintain the central high-temperature zone at a temperature level higher than the average temperature of the bed of the dense phase section, which is used for burning and gasifying the semi-coke fly ash particles with low reaction activity that are collected and returned from the high-temperature cyclone cracking furnace and the cyclone separator, and the high-temperature filter; the semi-coke fly ash particles separated from the high-temperature cyclone cracking furnace enter the dense phase section bed of the gasifier from the fly ash return port I above the distribution plate, and the semi-coke fly ash particles separated from the cyclone separator and the high-temperature filter The fly ash particles are introduced into the central high temperature zone of the dense phase section bed of the gasifier from the fly ash return port II; another part of the gasifying agent is introduced into the gas chamber of the gasifier to maintain the material in the dense phase section bed above the distribution plate in a stable fluidized state; the biomass feed port is located above the distribution plate, and is used to introduce biomass raw materials that have undergone raw material pretreatment; the secondary gasifying agent nozzle is located above the dense phase section bed of the gasifier, and is introduced with the secondary gasifying agent to promote further gasification of the solid and gas materials above the dense phase section of the gasifier and tar cracking reaction; the gasification of the solid and gas components in the gasifier and the cracking reaction of large molecular gases such as tar, as well as the sedimentation of large particles of solid continue to occur in the dilute phase section of the gasifier.

[0016] In another aspect of the present invention, the gas-solid phase material at the top outlet of the gasifier enters the high-temperature cyclone cracking furnace, and a cracking reaction catalyst is introduced between the top outlet of the gasifier and the high-temperature cyclone cracking furnace. At the same time, a gasifying agent is introduced at the opposite side of the gas-solid phase feed port of the high-temperature cyclone cracking furnace barrel, so that the fly ash, catalyst solid particles and tar-containing gas and the gas-solid phase between the gasifying agent in the high-temperature cyclone cracking furnace are fully mixed and react violently, and a catalytic cracking reaction of hydrocarbons such as tar and methane is generated while separating the gas and solid; the unreacted semi-coke fly ash containing catalyst particles separated from the high-temperature cyclone cracking furnace enters the material sealing valve, and is separated from the material sealing valve and the gas-solid phase by the gasifying agent. The dense phase bed of the gasifier is connected to the fly ash return port I above the distribution plate, and enters the dense phase bed of the gasifier to continue to participate in the reaction; the top gas-solid phase outlet of the high-temperature cyclone cracking furnace is connected to the heat recovery equipment, and the semi-coke fly ash particles separated by the cyclone separator enter the ash hopper from the bottom outlet of the lower cone section of the cyclone separator; the top dust-containing raw synthesis gas after gas-solid separation by the cyclone separator enters the high-temperature filter, and the semi-coke fly ash in the ash hopper and the bottom cone section of the high-temperature filter is transported to the fly ash discharge port II of the gasifier through the pneumatic conveying gas of carbon dioxide / air / nitrogen, and enters the central high-temperature area of ​​the dense phase bed of the gasifier to participate in combustion and gasification reactions.

[0017] In another aspect of the present invention, the high temperature filter introduces oxygen, oxygen-enriched or air gas below the dust removal filter element to form a continuous smoldering state for the dust covering the metal or ceramic high temperature filter element to reduce the pressure drop on both sides of the filter element.

[0018] The beneficial effects of the present invention are:

[0019] The raw material adaptability is strong, and the bed height is controllable. The bed material in the bed can quickly heat up the added biomass feed, shorten the gasification reaction time, greatly improve the gasification intensity of the gasifier, and generate more combustible components;

[0020] The spouted fluidized bed gasification technology with circulating return material is adopted. The unreacted carbon particles can be returned to the dense phase bed layer of the gasifier or the central high temperature area of ​​the dense phase bed layer through the return material device and pneumatic conveying for further reaction, which improves the gasification efficiency and the calorific value of the gas. At the same time, there is no excess fly ash discharged from the system, which effectively solves the problem of discharge and treatment of escaped fly ash in the fluidized bed gasification system.

[0021] A secondary gasifying agent nozzle is arranged at the bottom of the dilute phase section of the gasifier, which can effectively reduce the tar concentration in the dusty raw synthesis gas entering the dilute phase section of the gasifier by further increasing the temperature of the dilute phase section of the gasifier;

[0022] The tar cracking catalyst is directly added to the high-temperature pipeline between the top outlet of the gasifier and the high-temperature cyclone cracking furnace. The high-temperature cyclone is used to form a strong vortex. At the same time, a gasifying agent is introduced into the cyclone to fully mix the fly ash, catalyst solids, tar-containing gas, and gasifying agent in the high-temperature cyclone. The reaction is intense. While separating the gas and solid, catalytic cracking reactions of hydrocarbons such as tar and methane are generated. The reaction time is also effectively extended due to the internal and external reverse vortex flows generated in the cyclone, which can greatly reduce the tar content in the fluidized bed outlet gas and simplify the subsequent gas purification system. The cyclone cracking furnace equipment structure is also very simple.

[0023] The tar in the hot gas has been completely removed, so the hot gas after further dry dust removal can be directly used without causing pollution to the pipelines and equipment due to tar condensation, which correspondingly improves the thermal efficiency of gas utilization;

[0024] The tar produced in the biomass gasification process can be effectively converted into low molecular weight gas products such as hydrogen and carbon monoxide, which effectively increases the effective gas output per unit biomass consumption. Description of the drawings:

[0026] Figure 1 This is a schematic diagram of the device structure of Example 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the device structure of Example 2 of the present invention.

[0028] Figure 3 This is a schematic diagram of the gasifier furnace body structure and the division of various areas in the gasifier furnace used in the present invention.

[0029] In the attached figure: 1, gasifier, 2, high-temperature cyclone cracking furnace, 3, heat recovery equipment, 4, cyclone separator, 5, high-temperature filter, 6, material sealing valve, 7, steam drum, 8, ash hopper, 9, oxygen / oxygen-enriched / air / water vapor (gasifying agent), 10, secondary gasifying agent, 11, slag discharge, 12, raw biomass, 13, cracking reaction catalyst, 14, boiler feed water, 15, tar-removed synthesis gas, 16, oxygen / oxygen-enriched / air, 17, gasifier dilute phase section, 18, secondary gasifying agent nozzle, 19, gasifier dense phase section, 20, fly ash return port I, 21, distribution plate, 22, gasifying agent nozzle, 23, slag discharge ring pipe, 24, gasifier air chamber, 25, fly ash return port II, 26, biomass feed port. Specific implementation method:

[0031] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings and embodiments:

[0032] In the description of the present invention, it is necessary to understand that the description indicating the orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Example 1

[0035] A composite gasification system of biomass pressurized fluidized bed gasification and cyclone cracking, comprising a gasifier 1, a high-temperature cyclone cracking furnace 2, a heat recovery device 3, a cyclone separator 4, a high-temperature filter 5, a material sealing valve 6, a steam drum 7 and an ash hopper 8; the gasifier 1 comprises, from bottom to top, a slag discharge ring pipe, a gasifying agent nozzle, a gasifying furnace air chamber, a distribution plate, a fly ash return port II, a gasifying furnace dense phase section, a biomass feed port, a fly ash return port I, a secondary gasifying agent nozzle and a gasifying furnace dilute phase section, the slag discharge ring pipe is used to discharge the gasifier dense phase. The ash in the dense phase section bed is discharged from the gasifier, and the gasifying agent nozzle is used to spray the gasifying agent into the dense phase section bed of the gasifier; the solid discharge port of the high-temperature cyclone cracking furnace is connected with the solid feed port of the material sealing valve, and the solid discharge port of the material sealing valve is connected with the dense phase section bed of the gasifier through the fly ash return port I, the bottom outlet of the lower cone section of the cyclone separator is connected with the top feed port of the ash hopper, and the bottom discharge port of the ash hopper is connected with the dense phase section bed of the gasifier through the fly ash return port II, and the solid discharge port of the high-temperature filter is connected with the solid feed port of the high-temperature filter. The fly ash return port II is connected to the dense phase bed of the gasifier, the biomass feed port is located above the distribution plate, the secondary gasification agent nozzle is located above the dense phase bed of the gasifier, the top outlet of the gasifier is connected to the crude synthesis gas inlet of the high-temperature cyclone cracking furnace, and a gasification agent feed port is provided on the opposite side of the crude synthesis gas inlet of the high-temperature cyclone cracking furnace. The top gas-solid phase outlet of the high-temperature cyclone cracking furnace is connected to the heat recovery device, and the water / steam side of the heat recovery device is connected to the steam drum; the saturated water outlet at the bottom of the steam drum is connected to the saturated water inlet of the heat recovery device, the top saturated water / steam outlet on the water / steam side of the heat recovery device is connected to the saturated water / steam inlet at the bottom of the steam drum, the saturated steam outlet at the top of the steam drum is connected to the saturated steam inlet of the heat recovery device, and the superheated steam outlet of the heat recovery device is respectively connected to the gasification agent inlet of the cyclone cracking furnace and the gasification agent inlet of the gasification furnace gas chamber and the gasification agent nozzle of the gasifier; the bottom of the heat recovery device is connected to the gas-solid phase inlet of the cyclone separator, and the top outlet of the cyclone separator is connected to the crude synthesis gas inlet of the high-temperature filter. The heat recovery device 3 is used to partially recover the sensible heat of the high-temperature dusty raw synthesis gas and produce superheated steam as a byproduct. The cyclone separator 4 is used to further separate some solid particles in the dusty raw synthesis gas. The high-temperature filter 5 is used to further filter out the semi-coke fly ash particles in the dusty raw synthesis gas that cannot be separated by the cyclone separator 4. The semi-coke fly ash particles filtered out by the high-temperature filter 5 fall into the bottom cone section of the high-temperature filter 5. The filter element of the high-temperature filter 5 is a metal filter element or a ceramic filter element.The height of the dense phase bed of the gasifier is adjusted by controlling the slag discharge rate; there is a central high-temperature zone in the dense phase bed of the gasifier, and a gasifying agent containing a certain oxygen concentration is sprayed into the central high-temperature zone through a gasifying agent nozzle to maintain the central high-temperature zone at a temperature level higher than the average temperature of the dense phase bed, which is used for combustion and gasification of the semi-coke fly ash particles with low reaction activity that are collected and returned from the high-temperature cyclone cracking furnace and the cyclone separator and the high-temperature filter; the semi-coke fly ash particles separated from the high-temperature cyclone cracking furnace enter the dense phase bed of the gasifier from the fly ash return port I above the distribution plate, and the semi-coke fly ash particles separated from the cyclone separator and the high-temperature filter are filtered out. The fly ash return port II is introduced into the central high-temperature zone of the dense phase section bed of the gasifier; another part of the gasifying agent is introduced into the gas chamber of the gasifier to maintain the material in the dense phase section bed above the distribution plate in a stable fluidized state; the biomass feed port is located above the distribution plate, and is used to introduce biomass raw materials after raw material pretreatment; the secondary gasifying agent nozzle is located above the dense phase section bed of the gasifier, and the secondary gasifying agent is introduced to promote further gasification of the solid and gas materials above the dense phase section of the gasifier and tar cracking reaction; the gasification of the solid and gas components in the gasifier and the cracking reaction of large molecular gases such as tar, as well as the sedimentation of large particles of solid continue to occur in the dilute phase section of the gasifier. The gas-solid phase materials at the top outlet of the gasifier 1 enter the high-temperature cyclone cracking furnace 2, and a cracking reaction catalyst is introduced between the top outlet of the gasifier 1 and the high-temperature cyclone cracking furnace 2. At the same time, a gasifying agent is introduced at the opposite side of the gas-solid phase feed port of the cylinder of the high-temperature cyclone cracking furnace 2, so that the fly ash, catalyst solid particles and tar-containing gas and the gas-solid phase between the gasifying agent in the high-temperature cyclone cracking furnace 2 are fully mixed and react violently, and a catalytic cracking reaction of hydrocarbons such as tar and methane is generated while separating the gas and solid; the unreacted semi-coke fly ash containing catalyst particles separated from the high-temperature cyclone cracking furnace 2 enters the material sealing valve 6, and is connected to the dense phase bed of the gasifier 1 through the material sealing valve 6. The layer is connected to the fly ash return port I near the top of the distribution plate, and enters the dense phase bed layer of the gasifier 1 to continue to participate in the reaction; the top gas-solid phase outlet of the high-temperature cyclone cracking furnace 2 is connected to the heat recovery equipment 3, and the semi-coke fly ash particles separated by the cyclone separator 4 enter the ash hopper 8 from the bottom outlet of the lower cone section of the cyclone separator 4; the top dust-containing crude synthesis gas after gas-solid separation by the cyclone separator 4 enters the high-temperature filter 5, and the semi-coke fly ash in the ash hopper 8 and the bottom cone section of the high-temperature filter 5 is transported to the fly ash discharge port II of the gasifier 1 through the carbon dioxide / air / nitrogen pneumatic conveying gas, and enters the central high-temperature area of ​​the dense phase bed layer of the gasifier 1 to participate in combustion and gasification reactions.

[0036] The biomass pressurized fluidized bed gasification and cyclone cracking composite gasification system comprises a gasifier 1, a high-temperature cyclone cracking furnace 2, a heat recovery device 3, a cyclone separator 4, a high-temperature filter 5, a material sealing valve 6, a steam drum 7 and an ash hopper 8.

[0037] The gasifier 1 is composed of a slag discharge ring pipe, a gasifier nozzle, a gasifier air chamber, a distribution plate, a fly ash discharge port II, a gasifier dense phase section, a biomass feed port, a fly ash discharge port I, a secondary gasifier nozzle and a gasifier dilute phase section from bottom to top. The ash in the bed of the dense phase section of the gasifier is discharged from the gasifier by the slag discharge ring pipe. The height of the bed of the dense phase section of the gasifier can be adjusted accordingly by controlling the slag discharge rate. There is a central high-temperature zone in the bed of the dense phase section of the gasifier. The central high-temperature zone is sprayed with a gasifier containing a certain oxygen concentration through the gasifier nozzle to maintain the central high-temperature zone at a higher temperature than the average temperature of the dense phase section bed. It is used for combustion and gasification of the semi-coke fly ash particles with low reaction activity that are collected and returned from the high-temperature cyclone cracking furnace and the cyclone separator and the high-temperature filter. The semi-coke fly ash particles separated from the high-temperature cyclone cracking furnace enter the dense phase section of the gasifier from the fly ash return port I above the distribution plate. The cyclone separator and the high-temperature filter separate the semi-coke fly ash particles. The separated semi-coke fly ash particles are introduced into the central high-temperature zone of the dense phase section bed of the gasifier from the fly ash return port II; another part of the gasifier is introduced into the gas chamber of the gasifier to maintain the material in the dense phase section bed above the distribution plate in a stable fluidized state; the biomass feed port is located near the top of the distribution plate, and is used to introduce biomass raw materials that have been pretreated; the secondary gasifier nozzle is located near the top of the dense phase section bed of the gasifier, and the secondary gasifier is introduced to promote further gasification of the solid and gas materials above the dense phase section of the gasifier and tar cracking reaction; the gasification of the solid and gas components in the gasifier and the cracking reaction of large molecular gases such as tar, as well as the sedimentation of large particles of solid, continue to occur in the dilute phase section of the gasifier.

[0038] The gas-solid phase materials at the top outlet of the gasifier 1 enter the high-temperature cyclone cracking furnace 2, and a cracking reaction catalyst is introduced between the top outlet of the gasifier 1 and the high-temperature cyclone cracking furnace 2. At the same time, a gasifying agent is introduced at the opposite side of the gas-solid phase feed port of the cylinder of the high-temperature cyclone cracking furnace 2, so that the fly ash, catalyst solid particles and tar-containing gas and the gas-solid phase between the gasifying agent in the high-temperature cyclone cracking furnace 2 are fully mixed and react violently, and catalytic cracking reactions of hydrocarbons such as tar and methane are generated while separating the gas and solid; the unreacted semi-coke fly ash containing catalyst particles separated from the high-temperature cyclone cracking furnace 2 enters the material sealing valve 6, and is connected to the fly ash return port I above the distribution plate of the dense phase section bed of the gasifier 1 through the material sealing valve 6, and enters the dense phase section bed of the gasifier 1 to continue to participate in the reaction; the top gas-solid phase outlet of the high-temperature cyclone cracking furnace 2 is connected to the heat recovery equipment 3.

[0039] The heat recovery device 3 is used to partially recover the sensible heat of the high-temperature dusty raw synthesis gas and produce superheated steam as a by-product. The water / steam side of the heat recovery device 4 is connected to the drum 7; the drum 7 maintains its liquid level by supplementing boiler feed water; the saturated water outlet at the bottom of the drum 7 is connected to the saturated water inlet of the heat recovery device 4, the saturated water / steam outlet at the top of the water / steam side of the heat recovery device 4 is connected to the saturated water / steam inlet at the bottom of the drum 7, the saturated steam outlet at the top of the drum 7 is connected to the saturated steam inlet of the heat recovery device 4, and the superheated steam outlet of the heat recovery device 4 is respectively connected to the gasifying agent inlet of the cyclone cracking furnace 2 and the gasifying agent inlet of the gasifier gas chamber and the gasifying agent nozzle of the gasifier 1.

[0040] The dusty raw synthesis gas after partial cooling of the heat recovery device 3 is connected from the bottom of the heat recovery device 3 to the gas-solid phase inlet of the cyclone separator 4. The cyclone separator 4 is used to further separate some solid particles in the dusty raw synthesis gas. The semi-coke fly ash particles separated by the cyclone separator 4 enter the ash hopper 8 from the bottom outlet of the lower cone section of the cyclone separator 4; the dusty raw synthesis gas at the top after gas-solid separation by the cyclone separator 4 enters the high-temperature filter 5.

[0041] The high temperature filter 5 is used to further filter out the semi-coke fly ash particles in the dusty raw synthesis gas that cannot be separated by the cyclone separator 4. The semi-coke fly ash particles filtered out by the high temperature filter 5 fall into the bottom cone section of the high temperature filter 5; the raw synthesis gas after filtration and dust removal by the high temperature filter 5 does not contain tar and can be used directly or after further purification treatment.

[0042] The semi-coke fly ash in the bottom cone section of the ash hopper 8 and the high-temperature filter 5 is transported to the fly ash discharge port II of the gasifier 1 through pneumatic conveying gases such as carbon dioxide / air / nitrogen, and enters the central high-temperature area of ​​the dense phase bed of the gasifier 1 to participate in combustion and gasification reactions.

[0043] The high temperature filter 5 can be made of a metal filter element or a ceramic filter element.

[0044] Example 2

[0045] In this embodiment, a small amount of oxygen, oxygen-rich or air gas is introduced below the dust removal filter element of the high-temperature filter 5 in Embodiment 1 to form a continuous smoldering state for the dust covering the metal or ceramic high-temperature filter element, so as to reduce the pressure drop on both sides of the filter element.

[0046] In conclusion, the above is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the patent of the present invention.

Claims

1. A biomass pressurized fluidized bed gasification and cyclone cracking composite gasification system, characterized in that: The invention comprises a gasifier (1), a high-temperature cyclone cracking furnace (2), a heat recovery device (3), a cyclone separator (4), a high-temperature filter (5), a material sealing valve (6), a steam drum (7) and an ash hopper (8); the gasifier (1) comprises, from bottom to top, a slag discharge ring pipe, a gasifying agent nozzle, a gasifying furnace air chamber, a distribution plate, a fly ash return port II, a gasifying furnace dense phase section, a biomass feed port, a fly ash return port I, a secondary gasifying agent nozzle and a gasifying furnace dilute phase section, the slag discharge ring pipe is used to discharge ash in the bed layer of the gasifying furnace dense phase section out of the gasifier, and the gasifying agent nozzle is used to spray gasifying agent into the bed layer of the gasifying furnace dense phase section. agent; the solid discharge port of the high-temperature cyclone cracking furnace is communicated with the solid feed port of the material sealing valve, the solid discharge port of the material sealing valve is communicated with the dense phase section bed layer of the gasifier through the fly ash return port I, the bottom outlet of the lower cone section of the cyclone separator is communicated with the top feed port of the ash hopper, the bottom discharge port of the ash hopper is communicated with the dense phase section bed layer of the gasifier through the fly ash return port II, the solid discharge port of the high-temperature filter is communicated with the dense phase section bed layer of the gasifier through the fly ash return port II, the biomass feed port is located above the distribution plate, the secondary gasification agent nozzle is located above the dense phase section bed layer of the gasifier, and the top outlet of the gasifier is connected to the high-temperature cyclone The crude synthesis gas inlet of the wind cracking furnace is connected, a gasifying agent feed inlet is arranged on the opposite side of the crude synthesis gas inlet of the high-temperature cyclone cracking furnace, a gas-solid phase outlet at the top of the high-temperature cyclone cracking furnace is connected to a heat recovery device, a water / steam side of the heat recovery device is connected to a steam drum; a saturated water outlet at the bottom of the steam drum is connected to a saturated water inlet of the heat recovery device, a saturated water / steam outlet at the top of the water / steam side of the heat recovery device is connected to a saturated water / steam inlet at the bottom of the steam drum, a saturated steam outlet at the top of the steam drum is connected to a saturated steam inlet of the heat recovery device, and a superheated steam outlet of the heat recovery device is respectively connected to the gasifying agent inlet and The gasification chamber of the gasification furnace is connected to the gasification agent inlet of the gasification agent nozzle; the bottom of the heat recovery device is connected to the gas-solid phase inlet of the cyclone separator, and the top outlet of the cyclone separator is connected to the raw synthesis gas inlet of the high-temperature filter; the heat recovery device (3) is used to partially recover the sensible heat of the high-temperature dust-containing raw synthesis gas and produce superheated steam as a by-product; the semi-coke fly ash in the ash hopper (8) and the bottom cone section of the high-temperature filter (5) is transported to the fly ash return port II of the gasification furnace (1) through the carbon dioxide / air / nitrogen pneumatic conveying gas combination, and enters the central high-temperature zone of the dense phase section bed of the gasification furnace to participate in combustion and gasification reactions.

2. The biomass pressurized fluidized bed gasification and cyclone pyrolysis composite gasification system according to claim 1, characterized in that: The cyclone separator (4) is used to further separate some solid particles from the dusty raw synthesis gas.

3. The biomass pressurized fluidized bed gasification and cyclone pyrolysis composite gasification system according to claim 1, characterized in that: The high-temperature filter (5) is used to further filter out the semi-coke fly ash particles in the dusty raw synthesis gas that cannot be separated by the cyclone separator (4), and the semi-coke fly ash particles filtered out by the high-temperature filter (5) fall into the bottom cone section of the high-temperature filter (5).

4. The biomass pressurized fluidized bed gasification and cyclone pyrolysis composite gasification system according to claim 1, characterized in that: The filter element of the high temperature filter (5) is a metal filter element or a ceramic filter element.

5. The biomass pressurized fluidized bed gasification and cyclone pyrolysis composite gasification system according to claim 1, characterized in that: The height of the dense phase bed of the gasifier is adjusted by controlling the slag discharge rate; there is a central high temperature zone in the dense phase bed of the gasifier, and a gasifying agent containing a certain oxygen concentration is sprayed into the central high temperature zone through a gasifying agent nozzle to maintain the central high temperature zone at a higher temperature level than the average temperature of the dense phase bed, and is used for burning and gasifying the semi-coke fly ash particles with low reaction activity that are collected and returned from the high-temperature cyclone cracking furnace and the cyclone separator and the high-temperature filter; the semi-coke fly ash particles separated from the high-temperature cyclone cracking furnace enter the dense phase bed of the gasifier from the fly ash return port I above the distribution plate, and the semi-coke fly ash particles separated from the cyclone separator and the high-temperature filter are introduced into the central high temperature zone of the dense phase bed of the gasifier from the fly ash return port II; another part of the gasifying agent is introduced into the gas chamber of the gasifier to maintain the material in the dense phase bed above the distribution plate in a stable fluidized state; The biomass feed port is located above the distribution plate and is used to introduce biomass raw materials that have been pretreated. The secondary gasification agent nozzle is located above the bed layer of the dense phase section of the gasifier and is used to introduce secondary gasification agent to promote further gasification of solid and gas materials above the dense phase section of the gasifier and tar cracking reactions. The gasification of solid and gas components in the gasifier and cracking reactions of macromolecular gases such as tar, as well as the sedimentation of large particles of solid, continue to occur in the dilute phase section of the gasifier.

6. The biomass pressurized fluidized bed gasification and cyclone pyrolysis composite gasification system according to claim 5, characterized in that: The gas-solid phase material at the top outlet of the gasifier (1) enters the high-temperature cyclone cracking furnace (2), and a cracking reaction catalyst is introduced between the top outlet of the gasifier (1) and the high-temperature cyclone cracking furnace (2). At the same time, a gasifying agent is introduced into the opposite side of the gas-solid phase feed inlet of the cylinder of the high-temperature cyclone cracking furnace (2), so that the fly ash, catalyst solid particles and tar-containing gas and the gas-solid phase between the gasifying agent in the high-temperature cyclone cracking furnace (2) are fully mixed and react violently, and a catalytic cracking reaction of tar and hydrocarbons such as methane is generated while the gas and solid are separated; the tar-containing gas separated by the high-temperature cyclone cracking furnace (2) is The unreacted semi-coke fly ash of the catalyst particles enters the material seal valve (6), and is connected to the fly ash return port I above the distribution plate of the dense phase section of the gasifier through the material seal valve (6), and enters the dense phase section of the gasifier (1) to continue to participate in the reaction; the top gas-solid phase outlet of the high-temperature cyclone cracking furnace (2) is connected to the heat recovery device (3), and the semi-coke fly ash particles separated by the cyclone separator (4) enter the ash hopper (8) from the bottom outlet of the lower cone section of the cyclone separator (4); the top dust-containing raw synthesis gas after gas-solid separation by the cyclone separator (4) enters the high-temperature filter (5).

Images