Thermal power deep peak regulation coupling green ammonia generation system

Abstract

A thermal power deep peak regulation coupling green ammonia generation system is characterized in that an ammonia burner and a denitration reactor are arranged in a pulverized coal boiler, a high-temperature flue gas pipeline is arranged on the pulverized coal boiler on one side of the denitration reactor, a low-temperature flue gas pipeline is arranged on a tail flue of the pulverized coal boiler, and the other end of the high-temperature flue gas pipeline is connected with a biomass gasification device. The biomass gasification device is provided with a biomass feeding hole; high-temperature flue gas of the pulverized coal boiler enters the biomass gasification device through a high-temperature flue gas pipeline, and after heat exchange, flue gas of the biomass gasification device returns to a tail flue of the pulverized coal boiler through a low-temperature flue gas pipeline; the biomass gasification device is connected with the green ammonia synthesis device through a green hydrogen conveying pipeline, the output end of the green ammonia synthesis device is connected with the ammonia storage tank through an ammonia removal storage tank pipeline, and the ammonia storage tank is connected with the ammonia burner through a hearth ammonia removal pipeline. According to the invention, the unit can simultaneously realize four functions of assisting the thermal power unit to quickly change load, cleanly reduce carbon, synthesize green ammonia and denitrate flue gas.

Description

Technical Field

[0001] This invention relates to variable load and green ammonia synthesis technology for thermal power units, specifically to a deep peak shaving coupled green ammonia generation system for thermal power plants. Background Technology

[0002] As the proportion of new energy sources in the power grid system increases, thermal power units are shifting from initially serving base load to deep peak shaving. At the same time, the power grid is demanding rapid load changes and green, low-carbon performance from thermal power units. Currently, the pathways for reducing carbon emissions in thermal power are biomass co-firing, green ammonia co-firing, and carbon capture. Green ammonia is synthesized from green hydrogen and nitrogen, while green hydrogen is generally produced by electrolyzing water using electricity from renewable energy sources. Rapid load changes in thermal power units are constrained by the response speed of the main unit and pulverizing system.

[0003] CN111548826A discloses a method for retrofitting a biomass gas boiler using an MCFC (Multi-Cycle Fuel Cell) circulating loop fuel cell-biomass gas-pulverized coal coupling system to synthesize ammonia. The aim is to address the issues of coupling failure and inability to peak shaving that easily occur when clean energy supply is insufficient. This scheme utilizes an MCFC circulating loop fuel cell for grid-connected peak shaving of a pulverized coal boiler in a thermal power plant, and a biomass gas boiler for high-temperature steam-coupled peak shaving of the same boiler. This dual-layer coupling structure can simultaneously provide peak shaving for the pulverized coal boiler in the thermal power plant, or it can operate independently to achieve peak shaving. Direct grid connection of the MCFC circulating loop fuel cell can alleviate the coupling failure and inability to peak shaving problems caused by untimely straw supply.

[0004] However, this solution is limited in function and cannot achieve functions such as green ammonia synthesis and flue gas denitrification. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to simultaneously realize four functions of thermal power units: rapid load change, clean carbon reduction, green ammonia synthesis and flue gas denitrification, so as to meet the carbon reduction, green ammonia synthesis and rapid load change requirements of newly built and existing thermal power units. Therefore, a deep peak shaving coupled green ammonia generation system for thermal power is provided.

[0006] To solve the above problems, the present invention is achieved through the following technical solution: A deep peak-shaving coupled green ammonia generation system for thermal power includes a pulverized coal boiler, an ammonia burner and a denitrification reactor installed in the pulverized coal boiler, a high-temperature flue gas duct opened on the pulverized coal boiler on one side of the denitrification reactor, and a low-temperature flue gas duct opened on the tail flue of the pulverized coal boiler. The other end of the high-temperature flue gas duct is connected to a biomass gasification device, which is equipped with a biomass inlet. The high-temperature flue gas from the pulverized coal boiler enters the biomass gasification device through the high-temperature flue gas duct, and after heat exchange, the flue gas from the biomass gasification device returns to the tail flue of the pulverized coal boiler through the low-temperature flue gas duct. The biomass gasification unit is connected to the green ammonia synthesis unit via a green hydrogen transport pipeline. The output end of the green ammonia synthesis unit is connected to the ammonia storage tank via a pipeline to the ammonia storage tank. The ammonia storage tank is connected to the ammonia burner via a pipeline to the furnace.

[0007] The ammonia storage tank is also connected to a denitrification ammonia injection pipeline. The other end of the denitrification ammonia injection pipeline is mixed with the dilution air pipeline, and the end of the mixing pipeline is connected to the denitrification reactor.

[0008] The biomass gasification unit is a gasifier with a biomass feed inlet. The gasifier is divided into upper and lower sections: the upper section is the biomass gasification zone, and the lower section is the pipeline zone. High-temperature flue gas enters the pipeline zone and connects to the heat exchange pipeline within the pipeline zone. The other end of the heat exchange pipeline within the pipeline zone is connected to a low-temperature flue gas pipeline. A gasification gas pipeline is connected above the gasification zone of the biomass gasification unit, and the other end of the gasification gas pipeline is connected to a hydrogen separation unit. The hydrogen separation unit is connected to a green ammonia synthesis unit via a green hydrogen delivery pipeline.

[0009] The green ammonia synthesis unit is a synthesis reactor.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention enables the unit to simultaneously realize four functions, namely, rapid load change, clean carbon reduction, green ammonia synthesis and flue gas denitrification, and can be used in new and existing thermal power units with carbon reduction, green ammonia synthesis and rapid load change requirements. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0014] like Figure 1As shown, a deep peak-shaving coupled green ammonia generation system for thermal power includes a pulverized coal boiler 1, an ammonia burner 5 and a denitrification reactor 6 installed in the pulverized coal boiler, a high-temperature flue gas duct 101 opened on the pulverized coal boiler 1 on one side of the denitrification reactor 6, and a low-temperature flue gas duct 102 opened on the tail flue of the pulverized coal boiler 1. The other end of the high-temperature flue gas duct 101 is connected to a biomass gasification device 2, which is provided with a biomass inlet. The high-temperature flue gas from the pulverized coal boiler 1 enters the biomass gasification device 2 through the high-temperature flue gas duct 101. After heat exchange, the flue gas from the biomass gasification device 2 returns to the tail flue of the pulverized coal boiler 1 through the low-temperature flue gas duct 102. The biomass gasification device 2 is connected to the green ammonia synthesis device 3 via a green hydrogen transport pipeline 103. The output end of the green ammonia synthesis device 3 is connected to the ammonia storage tank 4 via an ammonia storage tank pipeline 104. The ammonia storage tank 4 is connected to the ammonia burner 5 via an ammonia gas pipeline 105.

[0015] Even better, the ammonia storage tank 4 is also connected to a denitrification ammonia injection pipe 106, the other end of which is mixed with the dilution air pipe 107, and the end of the mixing pipe is connected to the denitrification reactor 6.

[0016] Furthermore, the biomass gasification device 2 is a gasifier, which is equipped with a biomass feed inlet. The gasifier converts solid biomass (such as sawdust, straw, rice husks, etc.) into combustible gas (mainly composed of carbon monoxide, hydrogen, methane, etc.) under high temperature and limited oxygen conditions. In this invention, the gasifier is divided into upper and lower parts: the upper part is the biomass gasification zone 21, and the lower part is the pipeline zone 22. The high-temperature flue gas pipeline 101 enters the pipeline zone 22 and connects with the heat exchange pipeline within the pipeline zone 22. The other end of the heat exchange pipeline within the pipeline zone 22 is connected to the low-temperature flue gas pipeline 102. In this way, the high-temperature flue gas from the pulverized coal boiler 1 does not directly contact the biomass in the biomass gasification device 2, but only provides heat, realizing heat exchange between the flue gas and biomass, increasing the temperature of the biomass, and promoting gasification. The cooled flue gas then returns to the tail end of the boiler. A gasification gas pipeline 108 is connected above the gasification zone 21 of the biomass gasification device 2, and the other end of the gasification gas pipeline 108 is connected to the hydrogen separation device 7.

[0017] The biomass gasification unit 2 outputs biomass gasification gas (mainly composed of carbon monoxide, carbon dioxide, hydrogen, and water vapor). Therefore, biomass gasification unit 2 is connected to hydrogen separation unit 7 to extract hydrogen, which is then connected to green ammonia synthesis unit 3 via green hydrogen transmission pipeline 103. Other combustible gases from hydrogen separation unit 7 can be sold or used for other purposes.

[0018] Furthermore, the green ammonia synthesis unit 3 is a synthesis reactor, with one input being green hydrogen supplied by the green hydrogen delivery pipeline 103 and the other input being nitrogen. In the synthesis reactor, green hydrogen and nitrogen are synthesized into green ammonia, which is then stored in the ammonia storage tank 4 through the ammonia storage tank pipeline 104.

[0019] The working principle of this invention is: At the flue opening of the pulverized coal boiler 1, when the unit rapidly sheds its load, the flue gas is led to the biomass gasification unit 2 through the high-temperature flue gas pipeline 101, serving as the heat source for biomass gasification. The flue gas does not directly contact the biomass, only providing heat. After heat exchange, the flue gas returns to the tail flue of the pulverized coal boiler 1 through the low-temperature flue gas pipeline 102. After biomass gasification, green hydrogen is separated and sent to the green ammonia synthesis unit 3 through the green hydrogen conveying pipeline 103. Green hydrogen and nitrogen are synthesized into green ammonia in the green ammonia synthesis unit 3, and then stored in the ammonia storage tank 4 through the ammonia storage tank pipeline 104.

[0020] When the unit increases its load, green ammonia can be used as auxiliary fuel for the boiler, entering the ammonia burner 5 through the ammonia gas pipeline to the furnace 105 for combustion. Since the combustion of gaseous fuel in the furnace only takes tens of seconds, it helps the unit achieve rapid load increase before the pulverizing system reacts in time. The green ammonia in the ammonia storage tank 4 can be used as a combustion aid and stable fuel for the pulverized coal boiler 1, or it can be mixed with dilution air through the denitrification ammonia injection pipeline 106 and then enter the denitrification reactor 6 as a reducing agent for flue gas denitrification, or it can be sold or used for other purposes depending on the specific circumstances. The biomass gasification unit 2 can operate intermittently according to the unit's load adjustment, or it can use the extracted flue gas as an auxiliary heat source and other fuels as the main heat source for continuous operation.

[0021] Therefore, this invention proposes a green ammonia generation system coupled with variable load of thermal power units, and simultaneously realizes four functions: 1. Rapid load change of thermal power units: When the unit reduces the load, flue gas is drawn from the flue of the thermal power unit. The removal of flue gas causes a decrease in the heat absorption of steam, which causes the load on the turbine side to drop rapidly. When the unit increases the load, the generated green ammonia can be used as auxiliary fuel to enter the furnace for combustion (this process only takes tens of seconds), thereby assisting the unit to achieve rapid load increase.

[0022] 2. Clean Carbon Reduction: The high-temperature flue gas from the pulverized coal boiler 1 is used as the heat source for the biomass gasification device 2. The biomass gasification products are generally carbon monoxide, carbon dioxide, nitrogen, and hydrogen. Biomass is a zero-carbon emission fuel, and the hydrogen produced by biomass gasification is green hydrogen, which combines with nitrogen to synthesize green ammonia. This process involves biomass, effectively reducing carbon emissions.

[0023] 3. Green ammonia synthesis: After biomass gasification, green hydrogen is separated and sent to green ammonia synthesis unit 3 through green hydrogen transmission pipeline 103. Green hydrogen and nitrogen are synthesized into green ammonia in green ammonia synthesis unit 3. The generated green ammonia is sold or used for other purposes depending on the specific circumstances.

[0024] 4. Flue gas denitrification: The green ammonia in the ammonia storage tank 4 can be used as a combustion aid and stable fuel for the pulverized coal boiler 1, or it can be mixed with dilution air through the denitrification ammonia injection pipe 106 and then enter the denitrification reactor 6 as a reducing agent for flue gas denitrification.

[0025] Therefore, this invention enables the unit to simultaneously achieve four functions: rapid load change, clean carbon reduction, green ammonia synthesis, and flue gas denitrification. It can be used in new and existing thermal power units that have requirements for carbon reduction, green ammonia synthesis, and rapid load change.

[0026] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A deep peak-shaving coupled green ammonia generation system for thermal power plants, characterized in that: The system includes a pulverized coal boiler (1), an ammonia burner (5) and a denitrification reactor (6) are installed in the pulverized coal boiler, a high-temperature flue gas pipe (101) is opened on the pulverized coal boiler (1) on one side of the denitrification reactor (6), and a low-temperature flue gas pipe (102) is opened on the tail flue of the pulverized coal boiler (1). The other end of the high-temperature flue gas pipe (101) is connected to a biomass gasification device (2), and the biomass gasification device (2) is provided with a biomass feed inlet. The high-temperature flue gas of the pulverized coal boiler (1) enters the biomass gasification device (2) through the high-temperature flue gas pipe (101), and after heat exchange, the flue gas of the biomass gasification device (2) returns to the tail flue of the pulverized coal boiler (1) through the low-temperature flue gas pipe (102). The biomass gasification device (2) is connected to the green ammonia synthesis device (3) through the green hydrogen transport pipeline (103). The output end of the green ammonia synthesis device (3) is connected to the ammonia storage tank (4) through the ammonia storage tank pipeline (104). The ammonia storage tank (4) is connected to the ammonia burner (5) through the ammonia gas pipeline to the furnace (105).

2. The thermal power deep peak shaving coupled green ammonia generation system according to claim 1, characterized in that: The ammonia storage tank (4) is also connected to a denitrification ammonia spraying pipe (106). The other end of the denitrification ammonia spraying pipe (106) is mixed with the dilution air pipe (107). The end of the mixing pipe is connected to the denitrification reactor (6).

3. The thermal power deep peak shaving coupled green ammonia generation system according to claim 1, characterized in that: The biomass gasification device (2) is a gasifier with a biomass feed inlet. The gasifier is divided into two parts: the upper part is the biomass gasification zone (21) and the lower part is the pipeline zone (22). The high-temperature flue gas pipeline (101) enters the pipeline zone (22) and is connected to the heat exchange pipeline in the pipeline zone (22). The other end of the heat exchange pipeline in the pipeline zone (22) is connected to the low-temperature flue gas pipeline (102). The gasification gas pipeline (108) is connected above the gasification zone (21) of the biomass gasification device (2). The other end of the gasification gas pipeline (108) is connected to the hydrogen separation device (7). The hydrogen separation device (7) is connected to the green ammonia synthesis device (3) through the green hydrogen transport pipeline (103).

4. The thermal power deep peak shaving coupled green ammonia generation system according to claim 1, characterized in that: The green ammonia synthesis unit (3) is a synthesis reactor.

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