An IGFC system and method for conveying pulverized coal using high-temperature fuel cell anode tail gas

Abstract

The present invention discloses an IGFC system and method for conveying pulverized coal using tail gas from anode of a high-temperature fuel cell. Raw coal is ground and dried in a coal preparation unit to form dry pulverized coal. High-pressure tail gas generated by anode of a high-temperature fuel cell is conveyed to a gasifier. Oxygen generated by a cryogenic air separation unit is conveyed to a gasifier for reaction. Slag is produced at the bottom of the gasifier. High-temperature raw coal gas produced at the top is conveyed to a waste heat boiler. Raw coal gas after waste heat recovery by the waste heat boiler enters the hot side inlet of a first gas heater. Coal gas at the cold side outlet of the first gas heater enters the anode of a high-temperature fuel cell as fuel gas for reaction. The tail gas at the outlet of the anode of the high-temperature fuel cell is conveyed to a catalytic burner for combustion reaction. After generating high-temperature and high-pressure gas, it is conveyed to a waste heat boiler after work by a gas turbine. The combustion tail gas is discharged into the atmosphere after being cooled. This is beneficial to improving the cold gas efficiency of the gasifier, eliminating the need to prepare high-purity nitrogen, and reducing the energy consumption of air separation.

Description

Technical Field

[0001] The invention belongs to the field of coal power generation, and relates to an IGFC system and method for conveying pulverized coal by using high-temperature fuel cell anode tail gas. Background Art

[0002] Fuel cells provide conditions for the indirect use of coal. There are usually two ways to feed coal into the gasification device. The first is to use pneumatic conveying to deliver dry coal powder into the gasification device, and the other is to use a coal slurry pump to deliver wet water-coal slurry into the gasification device. The IGFC system configured with dry feed gasification has a higher net power generation efficiency, but an inert gas is required as the medium for pneumatic conveying. At present, most gasification devices use high-purity nitrogen produced by a cryogenic air separation system to transport dry coal powder into the gasification device. However, the cryogenic air separation system consumes more energy to produce high-purity nitrogen, and the high-purity nitrogen has a lower temperature and needs to be heated simultaneously in the gasification device, which consumes the chemical energy of the fuel and is not conducive to improving the cold coal gas efficiency of the gasifier. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an IGFC system and method for conveying pulverized coal using high-temperature fuel cell anode tail gas, which is beneficial to improving the cold gas efficiency of the gasifier, eliminating the need to prepare high-purity nitrogen, and reducing air separation energy consumption.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] An IGFC system using high-temperature fuel cell anode tail gas to transport pulverized coal comprises a coal preparation unit, a gasifier, a waste heat boiler, a first gas-to-gas heater, a high-temperature fuel cell, a catalytic burner, a gas turbine and a waste heat boiler connected in sequence;

[0006] The raw material outputted from the outlet of the coal preparation unit is dry coal powder, the anode outlet of the high-temperature fuel cell is connected to the outlet of the coal preparation unit, and the inlet of the gasifier is connected to the outlet of the deep-cold air separation unit.

[0007] Preferably, a flow valve is provided between the anode outlet of the high-temperature fuel cell and the gasifier inlet.

[0008] Preferably, the high-pressure steam outlet of the waste heat boiler is connected to a steam turbine, and the medium-pressure steam outlet of the steam turbine is connected to the gasifier.

[0009] Further, the medium-pressure steam outlet of the steam turbine is connected to the cold side outlet of the first gas-to-gas heater.

[0010] Preferably, an oxygen compressor is provided between the gasifier and the cryogenic air separation unit.

[0011] Preferably, the high-temperature fuel cell is connected to a cathode regenerator, the cold side inlet of the cathode regenerator is connected to air, and the cold side outlet is connected to the cathode inlet of the high-temperature fuel cell; the hot side inlet of the cathode regenerator is connected to the cathode outlet of the high-temperature fuel cell, and the hot side outlet is connected to the inlet of the catalytic burner.

[0012] Furthermore, an air compressor is connected to the cold side inlet of the cathode regenerator.

[0013] A working method of an IGFC system using a high temperature fuel cell anode tail gas to transport pulverized coal based on any of the above items comprises the following process:

[0014] The raw coal is ground and dried in the coal preparation unit to form dry coal powder, and the high-pressure tail gas generated by the anode of the high-temperature fuel cell is transported to the gasifier. The oxygen generated by the deep-cold air separation unit is sent to the gasifier for reaction. Slag is produced at the bottom of the gasifier, and the high-temperature raw coal gas produced at the top is sent to the waste heat boiler. The raw coal gas after the waste heat is recovered by the waste heat boiler enters the hot side inlet of the first gas heater, and the coal gas at the cold side outlet of the first gas heater enters the high-temperature fuel cell anode as fuel gas for reaction; the tail gas at the outlet of the high-temperature fuel cell anode is sent to the catalytic burner for combustion reaction. After generating high-temperature and high-pressure gas, it is sent to the waste heat boiler after passing through the gas turbine to do work, and the combustion tail gas is discharged into the atmosphere after cooling.

[0015] Preferably, medium-pressure steam is extracted from the middle of the steam turbine and fed into the gasifier for reaction; the medium-pressure steam extracted from the middle of the steam turbine is fed into the gasifier for reaction; the coal gas at the cold side outlet of the first gas-to-gas heater is mixed with the medium-pressure steam extracted from the middle of the steam turbine, the carbon monoxide component in the coal gas is diluted, and then fed into the anode of the high-temperature fuel cell.

[0016] Preferably, the air compressor pressurizes the ambient air and sends it into the cold side inlet of the cathode regenerator, and the high-temperature air at the cold side outlet of the cathode regenerator is sent to the cathode inlet of the high-temperature fuel cell, reacts in the high-temperature fuel cell, and then is sent to the hot side inlet of the cathode regenerator, and after being cooled, is sent to the catalytic burner for combustion reaction.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention uses high-temperature fuel cell anode tail gas as a medium for conveying dry coal powder. The high-temperature fuel cell anode tail gas is an inert gas relative to dry coal powder, and this tail gas has a relatively high temperature, a small temperature rise in the gasification device, and consumes less fuel chemical energy, which is beneficial to improving the cold gas efficiency of the gasifier; at the same time, it eliminates the need for a deep cold air separation device to prepare high-purity nitrogen, reduces air separation energy consumption, eliminates equipment such as a nitrogen compressor, simplifies the process flow, and reduces equipment investment. In this way, the present invention can improve the net power generation efficiency of the entire IGFC system.

[0019] Furthermore, the flow valve can control the flow rate of the anode tail gas of the high-temperature fuel cell during the process of conveying dry coal powder.

[0020] Furthermore, by mixing the medium-pressure steam extracted from the middle of the turbine with the coal gas at the cold side outlet of the first gas heater, the carbon monoxide component in the coal gas is diluted, making the composition of the fuel gas entering the high-temperature fuel cell more reasonable, thereby improving the net power generation efficiency of the IGFC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0022] Among them: 1-coal preparation unit; 2-gasification furnace; 3-waste heat boiler; 4-dust removal unit; 5-first gas-to-gas heater; 6-water scrubber; 7-second gas-to-gas heater; 8-carbonyl sulfide hydrolysis reactor; 9-low-temperature waste heat recovery unit; 10-coal gas cooler; 11-desulfurization unit; 12-humidifier; 13-water treatment unit; 14-sulfur recovery unit; 15-high-temperature fuel cell; 16-air compressor; 17-cathode regenerator; 18-catalytic burner; 19-gas turbine; 20-waste heat boiler; 21-steam turbine; 22-deep cold air separation unit; 23-oxygen compressor. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0024] like Figure 1 As shown, the IGFC system of the present invention adopting high-temperature fuel cell anode tail gas to transport pulverized coal includes a coal preparation unit 1, a gasification furnace 2, a waste heat boiler 3, a dust removal unit 4, a first gas heater 5, a high-temperature fuel cell 15, a catalytic burner 18, a gas turbine 19 and a waste heat boiler 20 connected in sequence.

[0025] The raw material outputted at the outlet of the coal preparation unit 1 is dry coal powder, the anode outlet of the high-temperature fuel cell 15 is connected to the outlet of the coal preparation unit 1 , and the inlet of the gasifier 2 is connected to the outlet of the deep cold air separation unit 22 .

[0026] A flow valve is provided between the anode outlet of the high-temperature fuel cell 15 and the inlet of the gasifier 2 , which can control the flow of the anode tail gas of the high-temperature fuel cell 15 during the process of conveying dry coal powder.

[0027] The high-pressure steam outlet of the waste heat boiler 20 is connected to the steam turbine 21, the medium-pressure steam outlet of the steam turbine 21 is connected to the gasifier 2, and the medium-pressure steam outlet of the steam turbine 21 is connected to the cold-side outlet of the first gas-to-gas heater 5. The medium-pressure steam extracted from the middle of the steam turbine 21 can be mixed with the coal gas at the cold-side outlet of the first gas-to-gas heater 5 to dilute the carbon monoxide component in the coal gas, so that the fuel gas composition entering the high-temperature fuel cell 15 is more reasonable, thereby improving the net power generation efficiency of the IGFC system.

[0028] An oxygen compressor 23 is provided between the gasifier 2 and the cryogenic air separation unit 22 .

[0029] The high temperature fuel cell 15 is connected to a cathode regenerator 17, the cold side inlet of the cathode regenerator 17 is connected to air, and the cold side outlet is connected to the cathode inlet of the high temperature fuel cell 15; the hot side inlet of the cathode regenerator 17 is connected to the cathode outlet of the high temperature fuel cell 15, and the hot side outlet is connected to the inlet of the catalytic burner 18. The cold side inlet of the cathode regenerator 17 is connected to an air compressor 16.

[0030] The hot side outlet of the first gas-to-gas heater 5 is connected to the inlet of the water scrubber 6, the outlet of the water scrubber 6 is connected to the hot side inlet of the second gas-to-gas heater 7, the hot side outlet of the second gas-to-gas heater 7 is connected to the inlet of the carbonyl sulfide hydrolysis reactor 8, the outlet of the carbonyl sulfide hydrolysis reactor 8 is connected to the cold side inlet of the second gas-to-gas heater 7, the cold side outlet of the second gas-to-gas heater 7 is connected to the inlet of the low-temperature waste heat recovery unit 9, the outlet of the low-temperature waste heat recovery unit 9 is connected to the inlet of the coal gas cooler 10, the outlet of the coal gas cooler 10 is connected to the inlet of the desulfurization unit 11, the outlet of the desulfurization unit 11 is respectively connected to the humidifier 12, the water treatment unit 13 and the sulfur recovery unit 14, and the outlet of the humidifier 12 is connected to the cold side inlet of the first gas-to-gas heater 5.

[0031] The working method of the IGFC system using high-temperature fuel cell anode tail gas to transport pulverized coal is as follows:

[0032] The raw coal is ground and dried in the coal preparation unit 1 to form dry coal powder, and the high-pressure tail gas generated by the anode of the high-temperature fuel cell 15 is transported to the gasifier 2. The pure oxygen at the outlet of the oxygen compressor 23 and the medium-pressure steam extracted from the middle of a small amount of the steam turbine 21 are simultaneously sent to the gasifier 2 for reaction. Slag is generated at the bottom of the gasifier 2, and the high-temperature raw coal gas generated at the top is sent to the waste heat boiler 3; the steam generated by the waste heat boiler 3 is sent to the waste heat boiler 20 for further heating. The raw coal gas after the waste heat is recovered by the waste heat boiler 3 is sent to the dust removal unit 4. The synthesis gas after cooling and dust removal enters the hot side inlet of the first gas heater 5, and is sent to the water washing tower 6 after cooling. The coal gas at the outlet of the water washing tower 6 is sent to the hot side inlet of the second gas-to-gas heater 7, and is sent to the carbonyl sulfide hydrolysis reactor 8 after further cooling, and then enters the cold side inlet of the second gas-to-gas heater 7. After being reheated, the coal gas enters the low-temperature waste heat recovery unit 9, and then enters the coal gas cooler 10. After the coal gas is reduced to the temperature required for the desulfurization process, it enters the desulfurization unit 11. The clean coal gas generated by the desulfurization unit 11 is sent to the humidifier 12 for humidification and then enters the cold side of the first gas-to-gas heater 5. The waste water and waste gas generated by the desulfurization unit 11 enter the water treatment unit 13 and the sulfur recovery unit 14 respectively to form solid salt and sulfur respectively.

[0033] After the coal gas at the cold side outlet of the first gas heater 5 is mixed with the medium-pressure steam extracted from the middle of the steam turbine 21, the carbon monoxide component in the coal gas is diluted and then used as fuel gas, which is sent to the anode of the high-temperature fuel cell 15 for reaction; a part of the tail gas at the anode outlet of the high-temperature fuel cell 15 is used as an inert medium to transport the dry coal powder produced by the coal preparation unit 1 to the gasifier 2, and the other part of the tail gas is sent to the catalytic burner 18 for combustion reaction, and after generating high-temperature and high-pressure gas, it is sent to the waste heat boiler 20 after the gas turbine 19 does work, and the combustion tail gas is discharged into the atmosphere after cooling. The air compressor 16 pressurizes the ambient air and sends it to the cold side inlet of the cathode regenerator 17. The high-temperature air at the cold side outlet is sent to the cathode inlet of the high-temperature fuel cell 15, reacts in the high-temperature fuel cell 15, and is sent to the hot side inlet of the cathode regenerator 17. After cooling, it is sent to the catalytic burner 18 for combustion reaction. The waste heat boiler 20 generates high-temperature and high-pressure steam and sends it to the steam turbine 21. The electric energy generated by the system is produced by the high temperature fuel cell 15, the gas turbine 19 and the steam turbine 21. The cryogenic air separation unit 22 produces high purity oxygen which is fed into the oxygen compressor 23 inlet.

[0034] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An IGFC system using high-temperature fuel cell anode tail gas to transport pulverized coal, characterized in that: It comprises a coal preparation unit (1), a gasifier (2), a waste heat boiler (3), a first gas-to-gas heater (5), a high-temperature fuel cell (15), a catalytic burner (18), a gas turbine (19) and a waste heat boiler (20) which are connected in sequence; The raw material outputted from the outlet of the coal preparation unit (1) is dry coal powder, the anode outlet of the high-temperature fuel cell (15) is connected to the outlet of the coal preparation unit (1), and the inlet of the gasifier (2) is connected to the outlet of the deep-cold air separation unit (22); A flow valve is provided between the anode outlet of the high-temperature fuel cell (15) and the inlet of the gasifier (2); The high-pressure steam outlet of the waste heat boiler (20) is connected to the steam turbine (21), and the medium-pressure steam outlet of the steam turbine (21) is connected to the gasifier (2); The high-temperature fuel cell (15) is connected to a cathode regenerator (17); a cold side inlet of the cathode regenerator (17) is connected to air, and a cold side outlet is connected to a cathode inlet of the high-temperature fuel cell (15); a hot side inlet of the cathode regenerator (17) is connected to a cathode outlet of the high-temperature fuel cell (15), and a hot side outlet is connected to an inlet of a catalytic burner (18).

2. The IGFC system for conveying pulverized coal using high-temperature fuel cell anode tail gas according to claim 1, characterized in that: The medium-pressure steam outlet of the steam turbine (21) is connected to the cold-side outlet of the first gas-to-gas heater (5).

3. The IGFC system for conveying pulverized coal using anode tail gas of a high temperature fuel cell according to claim 1, characterized in that: An oxygen compressor (23) is provided between the gasification furnace (2) and the cryogenic air separation unit (22).

4. The IGFC system for conveying pulverized coal using anode tail gas of a high temperature fuel cell according to claim 1, characterized in that: The cold side inlet of the cathode regenerator (17) is connected to an air compressor (16).

5. A method for operating an IGFC system using anode tail gas of a high temperature fuel cell to transport pulverized coal based on any one of claims 1 to 4, characterized in that: The process includes: The raw coal is ground and dried in the coal preparation unit (1) to form dry coal powder, and the high-pressure tail gas generated by the anode of the high-temperature fuel cell (15) is transported to the gasifier (2). The oxygen generated by the deep cold air separation unit (22) is sent to the gasifier (2) for reaction. Slag is generated at the bottom of the gasifier (2). The high-temperature raw coal gas generated at the top is sent to the waste heat boiler (3). The raw coal gas after the waste heat is recovered by the waste heat boiler (3) enters the hot side inlet of the first gas heater (5). The coal gas at the cold side outlet of the first gas heater (5) enters the anode of the high-temperature fuel cell (15) as fuel gas for reaction. The tail gas at the anode outlet of the high-temperature fuel cell (15) is sent to the catalytic burner (18) for combustion reaction. After generating high-temperature and high-pressure gas, it is sent to the waste heat boiler (20) after being worked by the gas turbine (19). The combustion tail gas is discharged into the atmosphere after being cooled.

6. The working method of the IGFC system using high temperature fuel cell anode tail gas to transport pulverized coal according to claim 5, characterized in that: The medium-pressure steam extracted from the middle of the steam turbine (21) is sent to the gasifier (2) for reaction; the medium-pressure steam extracted from the middle of the steam turbine (21) is sent to the gasifier (2) for reaction; the coal gas at the cold side outlet of the first gas heater (5) is mixed with the medium-pressure steam extracted from the middle of the steam turbine (21), the carbon monoxide component in the coal gas is diluted, and then sent to the anode of the high-temperature fuel cell (15).

7. The working method of the IGFC system using high temperature fuel cell anode tail gas to transport pulverized coal according to claim 5, characterized in that: The air compressor (16) pressurizes the ambient air and sends it to the cold side inlet of the cathode regenerator (17). The high-temperature air at the cold side outlet of the cathode regenerator (17) is sent to the cathode inlet of the high-temperature fuel cell (15). After reacting in the high-temperature fuel cell (15), it is sent to the hot side inlet of the cathode regenerator (17). After cooling, it is sent to the catalytic burner (18) for combustion reaction.

Images