Device and method for producing synthesis gas by gasifying slag from entrained flow gasification or fly ash from CFB gasification

Abstract

The invention relates to a device and method for producing synthesis gas by gasifying fluidized bed gasification slag or CFB gasification fly ash, and belongs to the field of chemical synthesis gas. A circulating fluidized bed combustion chamber (1) is connected to a high-efficiency cyclone separator (3), the lower part of the high-efficiency cyclone separator (3) is connected to a fluidized bed gasification furnace (2), and the lower part of the fluidized bed gasification furnace (2) is connected to the circulating fluidized bed combustion chamber (1); the top of the high-efficiency cyclone separator (3) is connected to a superheater (4), an evaporator (5), an economizer (6), an air preheater (7) and an exhaust gas treatment device (8) in sequence; the synthesis gas outlet of the fluidized bed gasification furnace (2) is connected to a high-efficiency cyclone separator (9), the lower part of the high-efficiency cyclone separator (9) is connected to the fluidized bed gasification furnace (2), and the top of the high-efficiency cyclone separator (9) is connected to a evaporator (10), an air preheater (12) and a synthesis gas purification device (15) in sequence, and then hydrogen-rich synthesis gas is transported outward. The present invention can realize the preparation of hydrogen-rich synthesis gas by gasifying slag from an entrained flow bed or gasifying fly ash from a CFB gasification bed, thereby achieving high-value utilization.

Description

Technical Field

[0001] The present invention belongs to the field of chemical synthesis gas, and in particular relates to a device and method for producing synthesis gas by gasifying slag from an entrained flow bed or fly ash from a CFB gasification bed. Background Art

[0002] As an important clean coal utilization technology, coal gasification technology is growing rapidly at an annual rate of 25-30%. The coal gasification process produces a large amount of coal gasification slag. According to statistics, my country's annual coal gasification slag emissions exceed 70 million tons. The rapid increase in coal gasification slag emissions, and due to factors such as high carbon content, extremely low volatile matter, and high moisture content, the current comprehensive utilization rate is low. Stockpiling and landfilling remain the main methods of coal gasification slag disposal. In addition, with the rapid rise of atmospheric pressure circulating fluidized bed coal gasification technology, more than 100 circulating fluidized bed gasifiers are now in operation, generating a large amount of gasification fly ash (bag-type ash). This fly ash has a high carbon content, extremely low volatile matter, no water, and a high calorific value (most of which exceeds 5000Kcal / kg).

[0003] To effectively address the resource utilization challenges of coal gasification slag and CFB (circulating fluidized bed) gasification fly ash, domestic research institutes and universities have successfully utilized circulating fluidized bed technology to combust coal gasification slag and CFB gasification fly ash after 15 years of research. However, this treatment method only addresses the disposal of coal gasification slag and CFB gasification fly ash, without addressing their high-value production. If entrained-flow gasification slag or CFB gasification fly ash can be secondary gasified to produce hydrogen-rich syngas, their high-value production could be realized. Furthermore, this hydrogen-rich syngas is precisely the feedstock gas that coal chemical companies urgently need. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of resource utilization of entrained flow gasification slag and CFB gasification fly ash, and to provide an apparatus and method for gasifying entrained flow gasification slag or CFB gasification fly ash to produce synthesis gas.

[0005] The present invention uses circulating fluidized bed high-temperature circulating ash as a heat source and high-temperature superheated steam as a gasifying agent to gasify fluidized bed gasification slag or CFB gasification fly ash to produce hydrogen-rich synthesis gas, thereby achieving high-value utilization of solid waste.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] Option 1: Entrained-bed slag gasification or CFB fly ash gasification to produce syngas device, including a circulating fluidized bed combustion chamber, a fluidized bed gasifier, a high-efficiency cyclone separator (1), a superheater (1), an evaporator (1), an economizer, an air preheater (1), tail gas treatment equipment, a high-efficiency cyclone separator (2), an evaporator (2), an air preheater (2), a screw feeder (1), a screw feeder (2), and syngas purification equipment;

[0008] The top of the screw feeder is provided with a feeding port 1, and the top of the screw feeder is provided with a feeding port 2. The discharge port of the screw feeder 1 is connected to the feed port of the circulating fluidized bed combustion chamber, and the discharge port of the screw feeder 2 is connected to the feed port 1 of the fluidized bed gasifier; the flue gas outlet at the top of the circulating fluidized bed combustion chamber is connected to the flue gas inlet of the high-efficiency cyclone separator 1, and the discharge port at the lower end of the high-efficiency cyclone separator is connected to the feed port 2 of the fluidized bed gasifier, and the discharge port of the fluidized bed gasifier is connected to the return material inlet of the circulating fluidized bed combustion chamber; the top of the high-efficiency cyclone separator The flue gas outlet is connected with the flue gas inlet of superheater 1, evaporator 1, economizer, air preheater 1 and tail gas treatment equipment in sequence; the synthesis gas outlet at the top of the fluidized bed gasifier is connected with the synthesis gas inlet of high-efficiency cyclone separator 2, and the discharge port at the lower end of high-efficiency cyclone separator 2 is connected with feed port 3 of the fluidized bed gasifier; the synthesis gas outlet at the top of high-efficiency cyclone separator 2 is connected with the synthesis gas inlet of evaporator 2, air preheater 2 and synthesis gas purification equipment in sequence; the steam generated by evaporator 1 and evaporator 2 is combined and enters superheater 1 through a pipeline.

[0009] Furthermore, the steam outlet of the superheater 1 is connected to the wind chamber at the bottom of the fluidized bed gasifier through a pipeline; the air outlet of the air preheater 1 is connected to the air inlet of the air preheater 2, and the air outlet of the air preheater 2 is connected to the wind chamber at the bottom of the circulating fluidized bed combustion chamber.

[0010] A method for producing synthesis gas by gasifying slag from an entrained flow gasification process or fly ash from a CFB gasification process, the method comprising the following steps:

[0011] Step 1: High-temperature air at 200-300°C is introduced into the wind chamber at the bottom of the circulating fluidized bed combustion chamber. At the same time, the entrained-bed gasification coarse slag or coal is fed into the circulating fluidized bed combustion chamber through a screw feeder 1 for combustion, reaching a temperature of 1000-1050°C. The high-temperature flue gas discharged through the flue gas outlet at the upper end of the circulating fluidized bed combustion chamber enters a high-efficiency cyclone separator 1, where the circulating material carried in the high-temperature flue gas is separated and fed into the fluidized bed gasifier from the bottom of the high-efficiency cyclone separator 1. The entrained-bed gasification slag or CFB gasification fly ash is fed into the fluidized bed gasifier through a screw feeder 2, where it is mixed with the high-temperature circulating material and high-temperature water vapor, and reacts at 900-950°C to generate hydrogen-rich synthesis gas.

[0012] Step 2: The high-temperature flue gas (1000-1050°C) discharged from the flue gas outlet at the top of the high-efficiency cyclone separator enters the superheater, where the steam is heated to 800-850°C and a pressure of 0.4-0.6 MPa. It is then fed into the wind chamber at the bottom of the fluidized bed gasifier. Simultaneously, the flue gas from the superheater enters the evaporator, economizer, air preheater, and tail gas treatment equipment in sequence before being discharged into the atmosphere.

[0013] Step 3: The high-temperature circulating material and high-temperature superheated steam heat the fluidized bed gasifier to 900-950℃. The carbon in the gasified slag or the carbon in the CFB gasified fly ash reacts with water vapor to generate synthesis gas. The steam to carbon mass ratio S / C daf =1.5~2.5:1, S represents steam, C daf It means dry ash-free carbon;

[0014] Step 4: The high-temperature synthesis gas coming out of the top of the fluidized bed gasifier first enters the high-efficiency cyclone separator 2 to separate the unreacted carbon and bed material carried by the synthesis gas, and is returned to the fluidized bed gasifier for cyclic gasification. The high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 passes through the evaporator 2 and the air preheater 2 in turn for heat exchange and is cooled to 200°C. It then enters the synthesis gas purification equipment and is then transported downstream.

[0015] Furthermore, in step 3, the carbon in the gasified slag or the carbon in the CFB gasified fly ash reacts with high-temperature steam at a temperature of 900-950°C to generate hydrogen-rich synthesis gas, wherein the hydrogen-rich synthesis gas is composed of H2, CO, CO2, and CH4, wherein: H2 accounts for 60%-65% by volume, CO accounts for 15-20% by volume, CO2 accounts for 15-20% by volume, and CH4 accounts for less than 1.5% by volume, and the carbon gas yield is 3.0-3.5Nm 3 / kg(C daf ), C daf Indicates dry ash-free carbon.

[0016] Option 2: Entrained-bed slag gasification or CFB fly ash gasification to produce syngas device, including a circulating fluidized bed gasification chamber, a fluidized bed gasifier, a high-efficiency cyclone separator 1, a superheater 2, a waste heat boiler, an economizer, an oxygen preheater, syngas purification equipment, a high-efficiency cyclone separator 2, a screw feeder 1 and a screw feeder 2;

[0017] The top of the screw feeder is provided with a feeding port 1, and the top of the screw feeder is provided with a feeding port 2. The discharge port of the screw feeder 1 is connected to the feed port of the circulating fluidized bed gasification chamber, and the discharge port of the screw feeder 2 is connected to the feed port 1 of the fluidized bed gasification furnace; the synthesis gas outlet at the top of the circulating fluidized bed gasification chamber is connected to the synthesis gas inlet of the high-efficiency cyclone separator 1, and the discharge port at the lower end of the high-efficiency cyclone separator is connected to the feed port 2 of the fluidized bed gasification furnace, and the discharge port of the fluidized bed gasification furnace is connected to the return material inlet of the circulating fluidized bed gasification chamber; the synthesis gas outlet at the top of the high-efficiency cyclone separator 1 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 1, and the discharge port at the lower end of the high-efficiency cyclone separator is connected to the feed port 2 of the fluidized bed gasification furnace, and the discharge port of the fluidized bed gasification furnace is connected to the return material inlet of the circulating fluidized bed gasification chamber; The outlet merges with the synthesis gas outlet of the high-efficiency cyclone separator II and is connected to the synthesis gas inlet of the superheater II, the synthesis gas outlet of the superheater II is connected to the synthesis gas inlet of the waste heat boiler, the synthesis gas outlet of the waste heat boiler is connected to the synthesis gas inlet of the economizer, the synthesis gas outlet of the economizer is connected to the synthesis gas inlet of the oxygen preheater, and the synthesis gas outlet of the oxygen preheater is connected to the synthesis gas purification equipment; the synthesis gas outlet at the top of the fluidized bed gasifier is connected to the synthesis gas inlet of the high-efficiency cyclone separator II, and the discharge port at the lower end of the high-efficiency cyclone separator II is connected to the feed port III of the fluidized bed gasifier.

[0018] Furthermore, the oxygen outlet of the oxygen preheater is connected to the wind chamber at the bottom of the circulating fluidized bed gasification chamber; the superheated steam outlet of the second superheater is connected to the wind chamber at the bottom of the circulating fluidized bed gasification chamber and the fluidized bed gasification furnace 2 respectively.

[0019] A method for producing synthesis gas by gasifying slag from an entrained flow gasification process or fly ash from a CFB gasification process, the method comprising the following steps:

[0020] Step 1: Pure oxygen and 800-850℃ superheated steam are introduced into the wind chamber at the bottom of the circulating fluidized bed gasification chamber; at the same time, the coarse slag from the entrained flow gasification or the fly ash from the CFB gasification is fed into the circulating fluidized bed gasification chamber through a screw feeder for gasification, with the temperature reaching 1000-1100℃ and the carbon gas production rate reaching 2.5-3.0Nm 3 / kg(C daf ), C daf Represents dry ash-free carbon; high-temperature syngas enters high-efficiency cyclone separator 1 through the syngas outlet at the upper end of the circulating fluidized bed gasification chamber. Circulating materials carried in the high-temperature syngas are separated by high-efficiency cyclone separator 1 and fed into the fluidized bed gasifier 2 from the bottom of the high-efficiency cyclone separator 1. The temperature of the fluidized bed gasifier 2 is maintained at 900-950°C by heating with high-temperature circulating ash and 800-850°C superheated steam. Fine slag from entrained bed gasification and crushed coarse slag from gasification or CFB gasification fly ash are fed into the fluidized bed gasifier 2 through screw feeder 2 and mixed with high-temperature circulating materials and high-temperature steam to react at 900-950°C to generate hydrogen-rich syngas.

[0021] Step 2: The high-temperature syngas at 1000-1100°C discharged from the syngas outlet at the top of the high-efficiency cyclone separator 1 and the hydrogen-rich syngas at 900-950°C discharged from the syngas outlet at the top of the high-efficiency cyclone separator 2 are combined and enter the superheater 2, where the steam temperature is heated to 800-850°C and the pressure is 0.4-0.6 MPa. Thereafter, the steam is respectively sent to the circulating fluidized bed gasification chamber and the bottom wind chamber of the fluidized bed gasifier; after entering the circulating fluidized bed gasification chamber, the steam reacts with oxygen and carbon to produce 1000-1100°C syngas; the steam enters the fluidized bed gasifier and heats the fluidized bed gasifier to 900-950°C with the high-temperature circulating material, and the carbon in the gasified slag or the carbon in the CFB gasification fly ash reacts with the high-temperature steam at a temperature of 900-950°C to produce hydrogen-rich syngas;

[0022] Step 3: The high-temperature synthesis gas coming out from the top of the fluidized bed gasifier enters the high-efficiency cyclone separator 2, separates the unreacted carbon and bed material carried by the synthesis gas, and returns them to the fluidized bed gasifier for circulating gasification. The high-temperature synthesis gas coming out from the top of the high-efficiency cyclone separator 2 is combined with the high-temperature synthesis gas separated from the high-efficiency cyclone separator 1 and enters the superheater 2. After passing through the synthesis gas outlet of the superheater 2, it enters the waste heat boiler, economizer, oxygen preheater and synthesis gas purification equipment in sequence, and then transports the synthesis gas to the downstream.

[0023] The beneficial effects of the present invention relative to the prior art are:

[0024] The present invention uses entrained-flow gasification slag or CFB gasification fly ash as raw materials to produce hydrogen-rich synthesis gas. The synthesis gas does not contain tar, and the heat exchange equipment does not have the problem of tar contamination. The present invention solves the problem that the existing technology cannot achieve high-value-added entrained-flow gasification slag and circulating fluidized-bed gasification fly ash, and converts the gasification slag or CFB gasification fly ash into hydrogen-rich synthesis gas, turning waste into treasure. The volume share of H2 in the synthesis gas is 60-65%, and H2+CO accounts for about 80%, which is a beneficial supplement to the synthesis gas of coal gasification enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the entrained-bed slag gasification and synthesis gas production device of the present invention, wherein the circulating fluidized-bed combustion chamber temperature is 1000-1050°C, and the fluidized-bed gasification furnace bed temperature is 900-950°C;

[0026] Figure 2 This is a schematic structural diagram of the CFB gasification fly ash gasification and synthesis gas production device of the present invention, wherein the circulating fluidized bed combustion chamber temperature is 1000-1050°C, and the fluidized bed gasification furnace bed temperature is 900-950°C;

[0027] Figure 3This is a schematic structural diagram of the entrained-bed gasification slag gasification and synthesis gas production device of the present invention, wherein the circulating fluidized-bed gasification chamber temperature is 1000-1100°C, and the fluidized-bed gasification furnace bed temperature is 900-950°C;

[0028] Figure 4 This is a schematic structural diagram of a CFB gasification fly ash gasification and synthesis gas production device of the present invention, wherein the circulating fluidized bed gasification chamber temperature is 1000-1100°C, and the fluidized bed gasification furnace bed temperature is 900-950°C.

[0029] The names of the components and their corresponding reference numerals in the above drawings are as follows:

[0030] Circulating fluidized bed combustion chamber 1, fluidized bed gasifier 2, high-efficiency cyclone separator 1 3, superheater 1 4, evaporator 1 5, economizer 6, air preheater 1 7, tail gas treatment equipment 8, high-efficiency cyclone separator 2 9, evaporator 2 10, air preheater 2 12, screw feeder 1 13, screw feeder 2 14, synthesis gas purification equipment 15, feed port 1 16, feed port 2 17, circulating fluidized bed gasification chamber 18, superheater 2 19, waste heat boiler 20, oxygen preheater 21. DETAILED DESCRIPTION

[0031] Specific implementation method 1: Figure 1 As shown, this embodiment discloses an entrained-bed slag gasification and synthesis gas production device, comprising a circulating fluidized-bed combustion chamber 1, a fluidized-bed gasifier 2, a high-efficiency cyclone separator 3, a superheater 4, an evaporator 5, an economizer 6, an air preheater 7, an exhaust gas treatment device 8, a high-efficiency cyclone separator 9, a second evaporator 10, a second air preheater 12, a first screw feeder 13, a second screw feeder 14, and a synthesis gas purification device 15;

[0032] A feeding port 16 is provided on the top of the screw feeder 13 (through which coarse slag from fluidized bed gasification is added into the screw feeder 13), and a feeding port 2 17 is provided on the top of the screw feeder 2 14 (through which fine slag from fluidized bed gasification and coarse slag less than 0.1 mm after crushing is added into the screw feeder 2 14). The discharge port of the screw feeder 13 is connected with the feed port of the circulating fluidized bed combustion chamber 1, and the discharge port of the screw feeder 2 14 is connected with the feed port 1 of the fluidized bed gasifier 2 (the feed port 1 is located on the side wall of the fluidized bed gasifier 2); the flue gas outlet at the top of the circulating fluidized bed combustion chamber 1 is connected with the flue gas inlet of the high-efficiency cyclone separator 3, and the discharge port at the lower end of the high-efficiency cyclone separator 3 is connected with the feed port 2 of the fluidized bed gasifier 2 (the feed port 2 is located at the upper end of the fluidized bed gasifier 2). The discharge port of the fluidized bed gasifier 2 is connected to the return material inlet of the circulating fluidized bed combustion chamber 1; the flue gas outlet at the top of the high-efficiency cyclone separator 3 is connected to the flue gas inlets of the superheater 4, the evaporator 5, the economizer 6, the air preheater 7 and the tail gas treatment equipment 8 in sequence; the synthesis gas outlet at the top of the fluidized bed gasifier 2 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 2 9, and the discharge port at the lower end of the high-efficiency cyclone separator 2 9 is connected to the feed port 3 of the fluidized bed gasifier 2 (the feed port 3 is located on the side wall of the fluidized bed gasifier 2 and above the feed port 1); the synthesis gas outlet at the top of the high-efficiency cyclone separator 2 9 is connected to the synthesis gas inlet of the evaporator 2 10, the air preheater 2 12 and the synthesis gas purification equipment 15 in sequence; the steam generated by the evaporator 5 and the evaporator 2 10 merges and enters the superheater 4 through the pipeline.

[0033] The steam outlet of the superheater 4 is connected to the bottom wind chamber of the fluidized bed gasification furnace 2 through a pipeline; the air outlet of the air preheater 7 is connected to the air inlet of the air preheater 2 12, and the air outlet of the air preheater 2 12 is connected to the bottom wind chamber of the circulating fluidized bed combustion chamber 1.

[0034] Specific implementation method 2: Figure 1 As shown, this embodiment discloses a method for producing synthesis gas by gasifying slag through an entrained flow process using the apparatus described in the first embodiment. The method comprises the following steps:

[0035] Step 1: High-temperature air at 200-300°C is introduced into the wind chamber at the bottom of the circulating fluidized bed combustion chamber 1; at the same time, the coarse slag from the entrained bed gasification (Note: the entrained bed gasification slag includes coarse slag and fine slag, of which the coarse slag accounts for 60-70%, with a particle size of ≤3mm, and the fine slag accounts for 30-40%, with an average particle size of 20μm) is fed into the circulating fluidized bed combustion chamber 1 through a screw feeder 13 for combustion, and the temperature reaches 1000-1050°C. The high-temperature flue gas discharged from the flue gas outlet at the upper end of the circulating fluidized bed combustion chamber 1 enters the high-efficiency cyclone separator 3 , the circulating material carried in the high-temperature flue gas is separated and fed into the fluidized bed gasifier 2 from the bottom of the high-efficiency cyclone separator 3; the entrained bed gasification slag (including the entrained bed gasification fine slag and the gasification coarse slag, the gasification coarse slag is crushed to a particle size of ≤0.1mm before entering the fluidized bed gasifier 2) is fed into the fluidized bed gasifier 2 through the screw feeder 2 14 and mixed with the high-temperature circulating material (1000-1050℃) and high-temperature steam (i.e., superheated steam, 800-850℃), and reacts at 900-950℃ to generate hydrogen-rich synthesis gas;

[0036] Step 2: The high-temperature flue gas (1000-1050°C) discharged from the flue gas outlet at the top of the high-efficiency cyclone separator 3 enters the superheater 4, where the steam is heated to a temperature of 800-850°C and a pressure of 0.4-0.6 MPa before being fed into the bottom air chamber of the fluidized bed gasifier 2. Simultaneously, the flue gas from the superheater 4 sequentially enters the evaporator 5, economizer 6, air preheater 7, and tail gas treatment equipment 8 before being discharged into the atmosphere.

[0037] Step 3: High-temperature circulating materials and high-temperature superheated steam (800-850°C) enter the fluidized bed gasifier 2 from the wind chamber, heating the fluidized bed gasifier 2 to 900-950°C. The carbon in the gasified slag reacts with the steam to generate synthesis gas. The mass ratio of steam to carbon in the gasified slag is S / C daf =1.5~2.5:1, S represents steam, C daf It means dry ash-free carbon;

[0038] Step 4: In the fluidized bed gasifier 2, the high-temperature circulating material and high-temperature superheated steam heat the fluidized bed gasifier 2 to 900-950°C. The carbon in the gasified slag reacts with the high-temperature steam at 900-950°C to produce hydrogen-rich synthesis gas;

[0039] Step 5: The high-temperature synthesis gas from the top of the fluidized bed gasifier 2 first enters the high-efficiency cyclone separator 9 to separate the unreacted carbon and bed material carried by the synthesis gas, and is then returned to the fluidized bed gasifier 2 for cyclic gasification. The high-temperature synthesis gas from the top of the high-efficiency cyclone separator 9 passes through the evaporator 10 and the air preheater 12 in sequence for heat exchange and is cooled to 200°C. It then enters the synthesis gas purification equipment 15 and is then transported downstream.

[0040] In this embodiment, the circulating fluidized bed combustion chamber uses fluidized bed gasification coarse slag as fuel, burns the combustion chamber outlet temperature to 1000-1050°C, and the gasified fine slag and coarse slag (less than 0.1mm after crushing) are fed into the fluidized bed gasifier 2. The temperature of the fluidized bed gasifier 2 is maintained at 900-950°C under heating with high-temperature circulating ash (1000-1050°C) and 800-850°C superheated steam.

[0041] Furthermore, in step 4, the carbon in the gasified slag reacts with high-temperature steam at a temperature of 900-950°C to generate hydrogen-rich synthesis gas, wherein the hydrogen-rich synthesis gas is composed of H2, CO, CO2, and CH4, wherein: H2 accounts for 60%-65% by volume, CO accounts for 15-20% by volume, CO2 accounts for 15-20% by volume, and CH4 accounts for less than 1.5% by volume, and the carbon gas yield is 3.0-3.5Nm 3 / kg(C daf ), C daf Indicates dry ash-free carbon.

[0042] The high-temperature circulating material and high-temperature superheated steam heat the fluidized bed gasifier 2 to 905°C. Test data (1): CO = 15.91%, CO2 = 17.83%, CH4 = 1.25%, H2 = 65.0%; test data (2) at 920°C: CO = 16.12%, CO2 = 18.85%, CH4 = 1.17%, H2 = 63.86%.

[0043] Specific implementation method three: Figure 2 As shown, this embodiment discloses a CFB gasification fly ash gasification synthesis gas production device (a device for producing hydrogen-rich synthesis gas by gasification of CFB gasification fly ash), including a circulating fluidized bed combustion chamber 1, a fluidized bed gasifier 2, a high-efficiency cyclone separator 3, a superheater 4, an evaporator 5, an economizer 6, an air preheater 7, an exhaust gas treatment device 8, a high-efficiency cyclone separator 9, a second evaporator 10, a second air preheater 12, a first screw feeder 13, a second screw feeder 14 and a synthesis gas purification device 15;

[0044] A feeding port 16 is provided on the top of the screw feeder 13 (coal is fed into the screw feeder 13 through the feeding port 1), a feeding port 2 17 is provided on the top of the screw feeder 2 14 (CFB gasification fly ash is fed into the screw feeder 2 14 through the feeding port 2), the discharge port of the screw feeder 13 is connected to the feed port of the circulating fluidized bed combustion chamber 1, the discharge port of the screw feeder 2 14 is connected to the feed port 1 of the fluidized bed gasifier 2 (feed port 1 is located on the side wall of the fluidized bed gasifier 2); the flue gas outlet at the top of the circulating fluidized bed combustion chamber 1 is connected to the flue gas inlet of the high-efficiency cyclone separator 3, the discharge port at the lower end of the high-efficiency cyclone separator 3 is connected to the feed port 2 of the fluidized bed gasifier 2 (feed port 2 is located at the upper end of the fluidized bed gasifier 2), the discharge port of the fluidized bed gasifier 2 It is connected to the return material inlet of the circulating fluidized bed combustion chamber 1; the flue gas outlet at the top of the high-efficiency cyclone separator 3 is connected to the flue gas inlets of the superheater 4, evaporator 5, economizer 6, air preheater 7 and tail gas treatment equipment 8 in sequence; the synthesis gas outlet at the top of the fluidized bed gasifier 2 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 2 9, and the discharge port at the lower end of the high-efficiency cyclone separator 2 9 is connected to the feed port 3 of the fluidized bed gasifier 2 (feed port 3 is located on the side wall of the fluidized bed gasifier 2 and above the feed port 1); the synthesis gas outlet at the top of the high-efficiency cyclone separator 2 9 is connected to the synthesis gas inlet of the evaporator 2 10, air preheater 2 12 and synthesis gas purification equipment 15 in sequence; the steam generated by the evaporator 5 and the evaporator 2 10 are combined and enter the superheater 4 through the pipeline.

[0045] The steam outlet of the superheater 4 is connected to the wind chamber at the bottom of the fluidized bed gasifier 2 through a pipeline;

[0046] The air outlet of the air preheater 1 7 is connected to the air inlet of the air preheater 2 12 , and the air outlet of the air preheater 2 12 is connected to the wind chamber at the bottom of the circulating fluidized bed combustion chamber 1 .

[0047] Specific implementation method four: Figure 2 As shown, this embodiment discloses a method for producing syngas by gasifying CFB fly ash using the apparatus described in the third embodiment, the method comprising the following steps:

[0048] Step 1: High-temperature air at 200-300°C is introduced into the wind chamber at the bottom of the circulating fluidized bed combustion chamber 1; at the same time, coal is fed into the circulating fluidized bed combustion chamber 1 through a screw feeder 13 and burned in the circulating fluidized bed combustion chamber 1, reaching a temperature of 1000-1050°C. The high-temperature flue gas discharged through the flue gas outlet at the upper end of the circulating fluidized bed combustion chamber 1 enters a high-efficiency cyclone separator 3, where the circulating material carried in the high-temperature flue gas is separated and fed into the fluidized bed gasifier 2 from the bottom of the high-efficiency cyclone separator 3. CFB gasification fly ash is fed into the fluidized bed gasifier 2 through a screw feeder 2 14 and mixed with the high-temperature circulating material (1000-1050°C) and high-temperature steam (i.e., superheated steam, 800-850°C), reacting at 900-950°C to generate hydrogen-rich synthesis gas;

[0049] Step 2: The high-temperature flue gas (1000-1050°C) discharged from the flue gas outlet at the top of the high-efficiency cyclone separator 3 enters the superheater 4, where the steam is heated to a temperature of 800-850°C and a pressure of 0.4-0.6 MPa before being fed into the bottom air chamber of the fluidized bed gasifier 2. Simultaneously, the flue gas from the superheater 4 sequentially enters the evaporator 5, economizer 6, air preheater 7, and tail gas treatment equipment 8 before being discharged into the atmosphere.

[0050] Step 3: High temperature circulating material and high temperature superheated steam (800-850℃) enter the fluidized bed gasifier 2 from the wind chamber, and heat the fluidized bed gasifier 2 to 900-950℃. The mass ratio of steam to carbon in CFB gasification fly ash S / C daf =1.5~2.5:1, S represents steam, C daf It means dry ash-free carbon;

[0051] Step 4: In the fluidized bed gasifier 2, the high-temperature circulating material and high-temperature superheated steam heat the fluidized bed gasifier 2 to 900-950°C. The carbon in the CFB gasification fly ash reacts with the high-temperature steam at this temperature to produce hydrogen-rich synthesis gas;

[0052] Step 5: The high-temperature synthesis gas from the top of the fluidized bed gasifier 2 first enters the high-efficiency cyclone separator 9 to separate the unreacted carbon and bed material carried by the synthesis gas, and is then returned to the fluidized bed gasifier 2 for cyclic gasification. The high-temperature synthesis gas from the top of the high-efficiency cyclone separator 9 passes through the evaporator 10 and the air preheater 12 in sequence for heat exchange and is cooled to 200°C. It then enters the synthesis gas purification equipment 15 and is then transported downstream.

[0053] Furthermore, the carbon in the CFB gasification fly ash reacts with high-temperature steam at a temperature of 900-950°C to generate hydrogen-rich synthesis gas, which is composed of H2, CO, CO2, and CH4, wherein: H2 accounts for 60%-65% by volume, CO accounts for 15-20% by volume, CO2 accounts for 15-20% by volume, and CH4 accounts for less than 1.50% by volume, with a carbon gas yield of 3.0-3.5Nm 3 / kg(C daf ), C daf Indicates dry ash-free carbon.

[0054] The high-temperature circulating material and high-temperature superheated steam heat the fluidized bed gasifier 2 to 905°C. Test data (1): CO = 18.22%, CO2 = 19.0%, CH4 = 1.0%, H2 = 61.77%; test data (2) at 920°C: CO = 18.61%, CO2 = 18.46%, CH4 = 0.84%, H2 = 62.08%.

[0055] In this embodiment, the circulating fluidized bed combustion chamber uses coal as fuel, and the combustion chamber outlet temperature is burned to 1000-1050°C. The circulating fluidized bed gasification fly ash is sent to the fluidized bed gasification furnace 2, and the temperature of the fluidized bed gasification furnace 2 is maintained at 900-950°C under heating with high-temperature circulating ash (1000-1050°C) and 800-850°C superheated steam temperature.

[0056] Specific implementation method five: Figure 3 As shown, this embodiment discloses an entrained-bed slag gasification synthesis gas production device (a device for producing hydrogen-rich synthesis gas by entrained-bed slag gasification), including a circulating fluidized-bed gasification chamber 18, a fluidized-bed gasification furnace 2, a high-efficiency cyclone separator 3, a superheater 19, a waste heat boiler 20, an economizer 6, an oxygen preheater 21, a synthesis gas purification device 15, a high-efficiency cyclone separator 9, a screw feeder 13, and a screw feeder 14;

[0057] A feeding port 16 is provided on the top of the screw feeder 13 (through which fluidized bed gasification coarse slag is added into the screw feeder 13), and a feeding port 2 17 is provided on the top of the screw feeder 2 14 (through which fluidized bed gasification fine slag and crushed coarse slag are added into the screw feeder 2). The discharge port of the screw feeder 13 is connected to the feed port of the circulating fluidized bed gasification chamber 18, and the discharge port of the screw feeder 2 14 is connected to the feed port 1 of the fluidized bed gasification furnace 2 (the feed port 1 is located on the side wall of the fluidized bed gasification furnace 2); the synthesis gas outlet at the top of the circulating fluidized bed gasification chamber 18 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 3, and the discharge port at the lower end of the high-efficiency cyclone separator 3 is connected to the feed port 2 of the fluidized bed gasification furnace 2 (the feed port 2 is located at the upper end of the fluidized bed gasification furnace 2). The inlet is connected to the return material inlet of the circulating fluidized bed gasification chamber 18; the synthesis gas outlet at the top of the high-efficiency cyclone separator 3 is merged with the synthesis gas outlet of the high-efficiency cyclone separator 29 and then connected to the synthesis gas inlet of the superheater 2 19, the synthesis gas outlet of the superheater 2 19 is connected to the synthesis gas inlet of the waste heat boiler 20, the synthesis gas outlet of the waste heat boiler 20 is connected to the synthesis gas inlet of the economizer 6, the synthesis gas outlet of the economizer 6 is connected to the synthesis gas inlet of the oxygen preheater 21, and the synthesis gas outlet of the oxygen preheater 21 is connected to the synthesis gas purification equipment 15; the synthesis gas outlet at the top of the fluidized bed gasifier 2 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 29, and the discharge port at the lower end of the high-efficiency cyclone separator 29 is connected to the feed port 3 of the fluidized bed gasifier 2 (the feed port 3 is located on the side wall of the fluidized bed gasifier 2 and above the feed port 1).

[0058] The oxygen outlet of the oxygen preheater 21 is connected to the bottom wind chamber of the circulating fluidized bed gasification chamber 18; the superheated steam outlet of the superheater 2 19 is connected to the bottom wind chamber of the circulating fluidized bed gasification chamber 18 and the fluidized bed gasification furnace 2 respectively.

[0059] Specific implementation method six: Figure 3 As shown, this embodiment discloses a method for producing synthesis gas by gasifying slag through an entrained flow process using the apparatus described in the fifth embodiment. The method includes the following steps:

[0060] Step 1: Pure oxygen and 800-850°C superheated steam (pure oxygen accounts for 40-45% of the total mass of superheated steam and oxygen) are introduced into the bottom wind chamber of the circulating fluidized bed gasification chamber 18; at the same time, the coarse slag from the entrained flow gasification is fed into the circulating fluidized bed gasification chamber 18 through a screw feeder 13 for gasification, with the temperature reaching 1000-1100°C and the carbon gas production rate being 2.5-3.0 Nm 3 / kg(C daf ), C dafRepresents dry ash-free carbon; the high-temperature synthesis gas enters the high-efficiency cyclone separator 3 through the synthesis gas outlet at the upper end of the circulating fluidized bed gasification chamber 18, and the circulating materials carried in the high-temperature synthesis gas are separated by the high-efficiency cyclone separator 3 and fed into the fluidized bed gasifier 2 from the bottom of the high-efficiency cyclone separator 3. The temperature of the fluidized bed gasifier 2 is maintained at 900-950°C under the heating of high-temperature circulating ash (1000-1100°C) and superheated steam at a temperature of 800-850°C; the fluidized bed gasification fine slag and the crushed gasification coarse slag (the particle size of the coarse slag after crushing is ≤0.1mm) are fed into the fluidized bed gasifier 2 through the screw feeder 2 14 and mixed with the high-temperature circulating material (1000-1100°C) and high-temperature steam (800-850°C), and react at 900-950°C to generate hydrogen-rich synthesis gas;

[0061] Step 2: The high-temperature synthesis gas at 1000-1100°C discharged from the synthesis gas outlet at the top of the high-efficiency cyclone separator 3 and the hydrogen-rich synthesis gas at 900-950°C discharged from the synthesis gas outlet at the top of the high-efficiency cyclone separator 2 9 are combined and then enter the superheater 2 19, where the steam temperature is heated to 800-850°C and the pressure is 0.4-0.6 MPa. Thereafter, the steam is respectively sent to the circulating fluidized bed gasification chamber 18 and the bottom wind chamber of the fluidized bed gasifier 2; after entering the circulating fluidized bed gasification chamber 18, it reacts with oxygen and carbon to produce synthesis gas at 1000-1100°C; then enters the fluidized bed gasifier 2 and the high-temperature circulating material to heat the fluidized bed gasifier 2 to 900-950°C, and the carbon in the gasified slag reacts with the high-temperature steam at a temperature of 900-950°C to produce hydrogen-rich synthesis gas;

[0062] Step 3: The high-temperature synthesis gas coming out of the top of the fluidized bed gasifier 2 enters the high-efficiency cyclone separator 2 9, and the unreacted carbon and bed material carried by the synthesis gas are separated and returned to the fluidized bed gasifier 2 for circulating gasification. The high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 9 is merged with the high-temperature synthesis gas separated from the high-efficiency cyclone separator 3 and then enters the superheater 2 19. After passing through the synthesis gas outlet of the superheater 19, it enters the waste heat boiler 20, the economizer 6, the oxygen preheater 21 and the synthesis gas purification equipment 15 in sequence, and then the synthesis gas is transported downstream.

[0063] In this embodiment, a circulating fluidized bed gasification chamber 18 (the circulating fluidized bed is a gasification furnace) and a fluidized bed gasification furnace 2 are used. The former is pure oxygen + steam gasification, and the latter is high-temperature steam gasification.

[0064] The circulating fluidized bed gasification chamber 18 uses fluidized bed gasification coarse slag as the gasification raw material and adopts pure oxygen + water vapor for gasification. The outlet temperature of the circulating fluidized bed gasification chamber 18 is 1000-1100°C. The gasified fine slag and the crushed coarse slag are sent to the fluidized bed gasification furnace 2. The temperature of the fluidized bed gasification furnace 2 is maintained at 900-950°C under the heating of high-temperature circulating ash (1000-1100°C) and 800-850°C superheated steam temperature.

[0065] The experimental results of the industrial test platform show that the composition of the synthesis gas at the outlet of the circulating fluidized bed gasification chamber 18 is as follows: CO: 19.76%, CO2: 24.97%, CH4: 0.84%, H2: 54.11%, and O2: 0.32%.

[0066] The composition of the synthesis gas at the outlet of fluidized bed gasification chamber 2 is: CO: 15.53%, CO2: 19.79%, CH4: 0.76%, H2: 63.92%.

[0067] The syngas at the outlet of the circulating fluidized bed gasification chamber 18 merges with the syngas of the fluidized bed gasification chamber 2, making the composition of the syngas more uniform and meeting the requirements of the syngas composition range.

[0068] Specific implementation method seven: Figure 4 As shown, this embodiment discloses a CFB gasification fly ash gasification synthesis gas production device, including a circulating fluidized bed gasification chamber 18, a fluidized bed gasifier 2, a high-efficiency cyclone separator 3, a superheater 19, a waste heat boiler 20, an economizer 6, an oxygen preheater 21, a synthesis gas purification device 15, a high-efficiency cyclone separator 9, a screw feeder 13 and a screw feeder 14;

[0069] A feeding port 16 is provided on the top of the screw feeder 13 (CFB gasification fly ash is added into the screw feeder 1 through the feeding port 1), and a feeding port 2 17 is provided on the top of the screw feeder 2 14 (CFB gasification fly ash is added into the screw feeder 2 14 through the feeding port 2 17). The discharge port of the screw feeder 13 is connected to the feed port of the circulating fluidized bed gasification chamber 18, and the discharge port of the screw feeder 2 14 is connected to the feed port 1 of the fluidized bed gasification furnace 2 (the feed port 1 is located on the side wall of the fluidized bed gasification furnace 2); the synthesis gas outlet at the top of the circulating fluidized bed gasification chamber 18 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 3, and the discharge port at the lower end of the high-efficiency cyclone separator 3 is connected to the feed port 2 of the fluidized bed gasification furnace 2 (the feed port 2 is located at the upper end of the fluidized bed gasification furnace 2), and the discharge port of the fluidized bed gasification furnace 2 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 3. The return material inlet of the circulating fluidized bed gasification chamber 18 is connected; the synthesis gas outlet at the top of the high-efficiency cyclone separator 3 is connected to the synthesis gas outlet of the high-efficiency cyclone separator 29 and then connected to the synthesis gas inlet of the superheater 2 19, the synthesis gas outlet of the superheater 2 19 is connected to the synthesis gas inlet of the waste heat boiler 20, the synthesis gas outlet of the waste heat boiler 20 is connected to the synthesis gas inlet of the economizer 6, the synthesis gas outlet of the economizer 6 is connected to the synthesis gas inlet of the oxygen preheater 21, and the synthesis gas outlet of the oxygen preheater 21 is connected to the synthesis gas purification equipment 15; the synthesis gas outlet at the top of the fluidized bed gasifier 2 is connected to the synthesis gas inlet of the high-efficiency cyclone separator 29, and the discharge port at the lower end of the high-efficiency cyclone separator 29 is connected to the feed port 3 of the fluidized bed gasifier 2 (the feed port 3 is located on the side wall of the fluidized bed gasifier 2 and above the feed port 1).

[0070] The oxygen outlet of the oxygen preheater 21 is connected to the wind chamber at the bottom of the circulating fluidized bed gasification chamber 18;

[0071] The superheated steam outlet of the second superheater 19 is communicated with the circulating fluidized bed gasification chamber 18 and the bottom wind chamber of the fluidized bed gasification furnace 2 respectively.

[0072] Specific implementation eight: Figure 4 As shown, this embodiment discloses a method for producing syngas by gasifying CFB fly ash using the apparatus described in the seventh embodiment, the method comprising the following steps:

[0073] Step 1: Pure oxygen and 800-850°C superheated steam (pure oxygen accounts for 40-45% of the total mass of superheated steam and oxygen) are introduced into the bottom air chamber of the circulating fluidized bed gasification chamber 18; at the same time, CFB gasification fly ash is fed into the circulating fluidized bed gasification chamber 18 through a screw feeder 13 for gasification, reaching a temperature of 1000-1100°C and a carbon gas yield of 2.5-3.0 Nm 3 / kg(C daf ), C dafRepresents dry ash-free carbon; the high-temperature synthesis gas enters the high-efficiency cyclone separator 3 through the synthesis gas outlet at the upper end of the circulating fluidized bed gasification chamber 18, and the circulating materials carried in the high-temperature synthesis gas are separated by the high-efficiency cyclone separator 3 and sent to the fluidized bed gasification furnace 2 from the bottom of the high-efficiency cyclone separator 3. The temperature of the fluidized bed gasification furnace 2 is maintained at 900-950°C under the heating of high-temperature circulating ash (1000-1100°C) and 800-850°C superheated steam temperature; CFB gasification fly ash is sent into the fluidized bed gasification furnace 2 through the screw feeder 2 14 and mixed with the high-temperature circulating material (1000-1100°C) and high-temperature water vapor (800-850°C), and reacts at 900-950°C to generate hydrogen-rich synthesis gas. Practice has shown that CFB gasification fly ash agglomerates in the circulating fluidized bed gasification chamber 18, and its particle size increases significantly, so that CFB gasification fly ash with an average particle size of about 20 μm can be separated in the high-efficiency cyclone separator 3 after being gasified in the circulating fluidized bed gasification chamber 18 and form a circulating material.

[0074] Step 2: The high-temperature syngas at 1000-1100°C discharged from the syngas outlet at the top of the high-efficiency cyclone separator 3 and the hydrogen-rich syngas at 900-950°C discharged from the syngas outlet at the top of the high-efficiency cyclone separator 2 9 are combined and then enter the superheater 2 19, where the steam temperature is heated to 800-850°C and the pressure is 0.4-0.6 MPa. Thereafter, the steam is respectively sent to the circulating fluidized bed gasification chamber 18 and the bottom wind chamber of the fluidized bed gasifier 2; after entering the circulating fluidized bed gasification chamber 18, it reacts with oxygen and carbon to produce syngas at 1000-1100°C; then enters the fluidized bed gasifier 2 and heats the fluidized bed gasifier 2 to 900-950°C with the high-temperature circulating material, and the carbon in the CFB gasification fly ash reacts with the high-temperature steam at a temperature of 900-950°C to produce hydrogen-rich syngas;

[0075] Step 3: The high-temperature synthesis gas coming out of the top of the fluidized bed gasifier 2 enters the high-efficiency cyclone separator 2 9, and the unreacted carbon and bed material carried by the synthesis gas are separated and returned to the fluidized bed gasifier 2 for circulating gasification. The high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 9 is merged with the high-temperature synthesis gas separated from the high-efficiency cyclone separator 3 and then enters the superheater 2 19. After passing through the synthesis gas outlet of the superheater 19, it enters the waste heat boiler 20, the economizer 6, the oxygen preheater 21 and the synthesis gas purification equipment 15 in sequence, and then the synthesis gas is transported downstream.

[0076] In this embodiment, the circulating fluidized bed gasification chamber 18 is pure oxygen + steam gasification, and the fluidized bed gasification furnace 2 is high temperature steam gasification.

[0077] The circulating fluidized bed gasifier 18 uses CFB gasification fly ash as the gasification feedstock, employing pure oxygen and steam for gasification. The outlet temperature of the circulating fluidized bed gasifier 18 is 1000-1100°C. The CFB gasification fly ash is fed into the fluidized bed gasifier 2, where the temperature is maintained at 900-950°C using high-temperature circulating ash (1000-1100°C) and superheated steam at 800-850°C. Experimental results on an industrial test platform indicate that the syngas composition at the outlet of the circulating fluidized bed gasifier 18 is: CO: 19.28%, CO2: 23.90%, CH4: 1.02%, H2=55.30%, and O2: 0.50%.

[0078] The composition of the synthesis gas at the outlet of fluidized bed gasification chamber 2 is: CO: 15.90%, CO2: 19.38%, CH4: 0.77%, H2: 63.95%.

[0079] After the two types of synthesis gas are combined, they meet the company's requirements for the synthesis gas composition range.

[0080] The above are only preferred specific implementation methods of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the patent of the present invention, who makes equivalent replacements or changes based on the technical solution of the patent of the present invention and the invention patent concept of the patent, should be covered by the scope of protection of the patent of the present invention.

Claims

1. A method for producing synthesis gas by gasifying slag from entrained flow gasification or fly ash from CFB gasification, characterized by: The method is implemented based on a device for producing synthesis gas by gasifying slag from an entrained flow or fly ash from a CFB gasification process. The device comprises a circulating fluidized bed gasification chamber (18), a fluidized bed gasification furnace (2), a high-efficiency cyclone separator (1) (3), a superheater (2) (19), a waste heat boiler (20), an economizer (6), an oxygen preheater (21), a synthesis gas purification device (15), a high-efficiency cyclone separator (2) (9), a first screw feeder (13) and a second screw feeder (14); The top of the spiral feeder 1 (13) is provided with a feeding port 1 (16), the top of the spiral feeder 2 (14) is provided with a feeding port 2 (17), the discharge port of the spiral feeder 1 (13) is connected to the feed port of the circulating fluidized bed gasification chamber (18), and the discharge port of the spiral feeder 2 (14) is connected to the feed port 1 of the fluidized bed gasification furnace (2); the synthesis gas outlet at the top of the circulating fluidized bed gasification chamber (18) is connected to the synthesis gas inlet of the high-efficiency cyclone separator 1 (3), the discharge port at the lower end of the high-efficiency cyclone separator 1 (3) is connected to the feed port 2 of the fluidized bed gasification furnace (2), and the discharge port of the fluidized bed gasification furnace (2) is connected to the return material inlet of the circulating fluidized bed gasification chamber (18); the synthesis gas outlet at the top of the high-efficiency cyclone separator 1 (3) is connected to the synthesis gas inlet of the high-efficiency cyclone separator 1 (3). The synthesis gas outlet is connected to the synthesis gas outlet of the high-efficiency cyclone separator (9) and then to the synthesis gas inlet of the superheater (19). The synthesis gas outlet of the superheater (19) is connected to the synthesis gas inlet of the waste heat boiler (20). The synthesis gas outlet of the waste heat boiler (20) is connected to the synthesis gas inlet of the economizer (6). The synthesis gas outlet of the economizer (6) is connected to the synthesis gas inlet of the oxygen preheater (21). The synthesis gas outlet of the oxygen preheater (21) is connected to the synthesis gas purification equipment (15). The synthesis gas outlet at the top of the fluidized bed gasifier (2) is connected to the synthesis gas inlet of the high-efficiency cyclone separator (9). The discharge port at the lower end of the high-efficiency cyclone separator (9) is connected to the feed port of the fluidized bed gasifier (2). The oxygen outlet of the oxygen preheater (21) is connected to the bottom wind chamber of the circulating fluidized bed gasification chamber (18); the superheated steam outlet of the second superheater (19) is connected to the bottom wind chamber of the circulating fluidized bed gasification chamber (18) and the fluidized bed gasification furnace (2). The method comprises the following steps: Step 1: Pure oxygen and 800-850℃ superheated steam are introduced into the bottom air chamber of the circulating fluidized bed gasification chamber (18); at the same time, the fluidized bed gasification coarse slag or CFB gasification fly ash is fed into the circulating fluidized bed gasification chamber (18) through the screw feeder (13) for gasification, with the temperature reaching 1000-1100℃ and the carbon gas production rate of 2.5-3.0Nm 3 / kg(C daf ), C daf Represents dry ash-free carbon; the high-temperature synthesis gas enters the high-efficiency cyclone separator (3) through the synthesis gas outlet at the upper end of the circulating fluidized bed gasification chamber (18), and the circulating material carried in the high-temperature synthesis gas is separated by the high-efficiency cyclone separator (3) and sent to the fluidized bed gasification furnace (2) from the bottom of the high-efficiency cyclone separator (3), and the temperature of the fluidized bed gasification furnace (2) is maintained at 900-950°C under the heating of high-temperature circulating ash and 800-850°C superheated steam temperature; the fluidized bed gasification fine slag and the crushed gasification coarse slag or CFB gasification fly ash are sent into the fluidized bed gasification furnace (2) through the screw feeder (14) and mixed with the high-temperature circulating material and superheated steam, and reacted at 900-950°C to generate hydrogen-rich synthesis gas; Step 2: The 1000-1100℃ high temperature synthesis gas discharged from the synthesis gas outlet of the top of the high efficiency cyclone separator 1 (3) and the 900-950℃ hydrogen-rich synthesis gas discharged from the synthesis gas outlet of the top of the high efficiency cyclone separator 2 (9) are combined and then enter the superheater 2 (19), and the steam temperature is heated to 800-850℃ to form superheated steam with a pressure of 0.4-0.6Mpa. After that, the superheated steam is respectively sent to the circulating fluidized bed gasification chamber (18) and the bottom wind chamber of the fluidized bed gasifier (2); after entering the circulating fluidized bed gasifier chamber (18), the gasification reaction occurs with the carbon together with oxygen to produce 1000-1100°C synthesis gas; entering the fluidized bed gasifier (2) and heating the fluidized bed gasifier (2) to 900-950°C with the high-temperature circulating material, and the carbon in the gasified slag or the carbon in the CFB gasified fly ash reacts with the superheated steam at a temperature of 900-950°C to produce hydrogen-rich synthesis gas; Step 3: The high-temperature synthesis gas coming out of the top of the fluidized bed gasifier (2) enters the high-efficiency cyclone separator 2 (9), and the unreacted carbon and bed material carried by the synthesis gas are separated and returned to the fluidized bed gasifier (2) for circulating gasification. The high-temperature synthesis gas coming out of the top of the high-efficiency cyclone separator 2 (9) is combined with the high-temperature synthesis gas separated from the high-efficiency cyclone separator 1 (3) and enters the superheater 2 (19). After passing through the synthesis gas outlet of the superheater 2 (19), it enters the waste heat boiler (20), the economizer (6), the oxygen preheater (21) and the synthesis gas purification equipment (15) in sequence, and then the synthesis gas is transported downstream.

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