A liquid ammonia and coal-fired complementary power generation system and method

Abstract

The present invention relates to a liquid ammonia and coal-fired complementary power generation system and method, the system includes a main burner and a separate overburnt air burner arranged in a furnace, an economizer, an ammonia injection grid, an SCR denitration reactor and an air preheater are arranged in sequence in the tail flue connected to the furnace outlet flue, and an ammonia fuel burner is arranged in the main burner area; the ammonia injection grid is arranged on the inlet flue of the SCR denitration reactor; an SCR inlet flue gas sampling device is arranged on the flue between the economizer outlet and the ammonia injection grid; an SCR outlet flue gas sampling device is arranged on the flue between the SCR denitration reactor and the air preheater; the system also includes an ammonia supply device, which is respectively connected to the ammonia fuel burner and the ammonia injection grid. In the present invention, not all ammonia fuel is directly sprayed into the furnace, and this design method can improve the efficiency of the mixed combustion of ammonia fuel and coal powder, which is conducive to the ignition and stable combustion of ammonia fuel.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon emission reduction in thermal power plants, and in particular relates to a liquid ammonia and coal-fired complementary power generation system and method. Background Art

[0002] As an important source of CO2 emissions, the thermal power industry basically accounts for a quarter of the total domestic CO2 emissions. In the future, thermal power plants will face tremendous pressure to reduce CO2 emissions. Therefore, technical measures such as energy-saving upgrades, fuel clean substitution, and new CO2 capture devices should be adopted in the coal-fired power industry to meet future carbon emission requirements and truly achieve the goals of carbon peak and carbon neutrality. However, my country's energy structure is mainly coal-based, which will not change for a long time in the future. Thermal power is the main power source in power installations. Coal-fired power generation, as the main power source, shoulders the ballast and bottom-line backup functions in the power grid and cannot be shaken in the short term. Coal-fired power generation units are facing tremendous pressure to reduce carbon emissions. In the absence of large-scale reductions in power generation, new paths need to be opened up to control CO2 emissions.

[0003] Carbon emission reduction management and transformation of coal-fired power units will become the main way for coal-fired power to cope with the carbon market in the future. By adopting carbon detection and carbon emission management, real-time carbon emission measurement and carbon accounting of coal-fired power units can be carried out, so as to understand the carbon emission characteristics of the units more clearly; and technical transformation of units will become the main means to reduce carbon emissions. At present, the main way to reduce CO2 emissions of coal-fired power units is to reduce the coal consumption of power generation units through energy-saving and efficiency-improvement methods. Under the premise of the same power generation / heat supply, the coal consumption is reduced, thereby reducing CO2 emissions. The main problem at present is that the transformation and upgrading of coal-fired power unit equipment requires a large investment cost, which can only bring limited energy saving, and the CO2 emission reduction effect is not obvious. In addition, the poor economic benefits have affected the motivation for investment in coal-fired power unit equipment transformation. Therefore, there are many obstacles in the implementation of this technical route. Only when the carbon quota price is high enough, after the energy-saving transformation of coal-fired power units, the reduced CO2 emissions can recover part of the cost through the carbon trading market, thereby promoting energy-saving transformation. However, due to the constraints of thermodynamic cycles and basic physical laws, the space for exploring energy-saving potential is limited, and it is impossible to fundamentally achieve deep emission reductions of coal-fired power units.

[0004] Another way is to retrofit the unit with heat supply to reduce the coal consumption for power generation. In the process of calculating energy consumption, the energy-saving benefits will be attributed to the power generation side. It has no necessary connection with the CO2 emissions of the cogeneration unit. If the heating supply is increased, the CO2 emissions of the unit will increase instead. Summary of the invention

[0005] In order to overcome the deficiency of the existing technical solutions that CO2 cannot be significantly reduced, the present invention provides a liquid ammonia and coal-fired complementary power generation system and method, which utilizes zero-carbon NH3 as a supplementary fuel for coal-fired boilers, and burns it together with coal to generate electricity, thereby reducing the coal consumption of coal-fired power units, thereby achieving the same output (same power generation and heat supply) when the CO2 emissions of coal-fired power units are reduced, and NH3, as a combustion-supporting fuel, is conducive to the combustion of coal, thereby improving the stable combustion capacity of coal-fired units under low load, achieving deep peak regulation of the units, thereby providing load space for the consumption of new energy, further reducing the power generation of coal-fired power units, and reducing the total CO2 emissions of coal-fired units.

[0006] The liquid ammonia and coal-fired complementary power generation system involved in the present invention comprises a furnace, a main burner and a separate overburnt air burner arranged in the furnace, an economizer, an ammonia injection grid, an SCR denitrification reactor and an air preheater are arranged in sequence in the tail flue connected to the furnace outlet flue, and an ammonia fuel burner is arranged in the main burner area; the ammonia injection grid is arranged on the inlet flue of the SCR denitrification reactor; an SCR inlet flue gas sampling device is arranged on the flue between the economizer outlet and the ammonia injection grid, and the SCR inlet flue gas sampling device is connected to the SCR inlet flue gas component analysis device; an SCR outlet flue gas sampling device is arranged on the flue between the SCR denitrification reactor and the air preheater, and the SCR outlet flue gas sampling device is connected to the SCR outlet flue gas component analysis device; the system also comprises an ammonia supply device, and the ammonia supply device is respectively connected to the ammonia fuel burner and the ammonia injection grid.

[0007] Furthermore, the ammonia supply device includes a liquid ammonia storage tank, a liquid ammonia pump and a gasification device connected in sequence, wherein the outlet of the gasification device is divided into two routes, the first outlet of the gasification device is connected to the ammonia fuel burner in sequence via a fuel ammonia shut-off valve and a fuel ammonia regulating valve; the second outlet of the gasification device is connected to the ammonia injection grid in sequence via a reduction ammonia shut-off valve and a reduction ammonia regulating valve.

[0008] Furthermore, the ammonia supply device includes a liquid ammonia pump connected to a liquid ammonia storage tank and a gasification device, wherein the outlet of the liquid ammonia pump is divided into two routes, the first outlet of the liquid ammonia pump is connected to the gasification device, and the outlet of the gasification device is connected to the ammonia injection grid via a reduction ammonia shut-off valve and a reduction ammonia regulating valve in sequence; the second outlet of the liquid ammonia pump is connected to the ammonia fuel burner via a fuel ammonia shut-off valve and a fuel ammonia regulating valve in sequence.

[0009] Furthermore, the cross-sectional shape of the ammonia fuel burner is rectangular or circular, and it comprises a two-layer structure, one layer is a hollow structure, and the other layer is a grid structure.

[0010] Furthermore, the grid structure of the ammonia fuel burner is a catalyst cracking area, which is filled with a catalyst for catalytic cracking of ammonia; and the hollow structure of the ammonia fuel burner is a non-catalytic cracking area.

[0011] Furthermore, the main burners are symmetrically distributed on the side walls of the furnace, and the separated overfire air burners are located at the upper end of the main burners; and the ammonia fuel burners are symmetrically distributed in the main burner area.

[0012] The present invention also relates to a method for complementary power generation of liquid ammonia and coal, which utilizes the above-mentioned system, and the method has the following steps: liquid ammonia pumped out from a liquid ammonia storage tank by a liquid ammonia pump is heated into gaseous ammonia by a gasification device; the gaseous ammonia enters an ammonia fuel burner through a first outlet of the gasification device in sequence through a fuel ammonia shut-off valve and a fuel ammonia regulating valve, and is mixed with pulverized coal in the main burner area in the furnace for combustion; the flue gas after combustion continues to burn through a separated burnout air burner, and enters an SCR denitration reactor through an economizer; the gaseous ammonia enters an ammonia injection grid through a second outlet of the gasification device through a reduced ammonia shut-off valve and a reduced ammonia regulating valve, is mixed with the flue gas after combustion and enters the SCR denitration reactor.

[0013] The present invention also relates to a method for complementary power generation of liquid ammonia and coal, which utilizes the above-mentioned system, and the method has the following steps: the liquid ammonia that is pressurized and transported to the second outlet of the liquid ammonia storage tank by a liquid ammonia pump enters the ammonia fuel burner through a fuel ammonia shut-off valve and a fuel ammonia regulating valve, and is mixed with the pulverized coal in the main burner area in the furnace for combustion; the flue gas after combustion continues to burn through a separated overburnt air burner, and enters the SCR denitrification reactor through an economizer; the liquid ammonia that is pressurized and transported to the first outlet of the liquid ammonia storage tank by a liquid ammonia pump is heated into gaseous ammonia through a gasification device; the gaseous ammonia enters the ammonia injection grid through the outlet of the gasification device through a reduction ammonia shut-off valve and a reduction ammonia regulating valve, is mixed with the flue gas after combustion and enters the SCR denitrification reactor.

[0014] Furthermore, liquid ammonia or gaseous ammonia enters the ammonia fuel burner through the fuel ammonia shut-off valve and the fuel ammonia regulating valve, and is sprayed by the ammonia fuel burner. A portion of the liquid ammonia or gaseous ammonia enters the catalytic cracking area of ​​the ammonia fuel burner and is cracked into hydrogen and nitrogen; the other portion of the liquid ammonia or gaseous ammonia enters the non-catalytic cracking area of ​​the ammonia fuel burner; the two portions of fuel are fed into the furnace together and mixed with the pulverized coal in the main burner area for combustion.

[0015] Furthermore, the NO after the mixed combustion of pulverized coal is analyzed by the SCR inlet flue gas sampling device connected to the flue between the economizer outlet and the ammonia injection grid, and the SCR inlet flue gas component analysis device connected to the SCR inlet flue gas sampling device. x concentration and NH3 concentration.

[0016] Furthermore, when the NH3 concentration measured by the SCR inlet flue gas composition analysis device is greater than NO x When the concentration is low, close the fuel ammonia regulating valve to reduce the amount of fuel ammonia entering the furnace, increase the amount of ammonia fuel in the catalytic cracking area of ​​the ammonia fuel burner, and reduce the amount of ammonia fuel in the non-catalytic cracking area of ​​the ammonia fuel burner until the NH3 concentration is lower than 100ppm.

[0017] Furthermore, when the NH3 concentration measured by the SCR inlet flue gas component analysis device is higher than 100ppm, the air supply volume of the ammonia fuel burner and the secondary air nozzles in the upper and lower areas is increased; at the same time, the amount of ammonia fuel in its catalytic cracking area is increased, and the amount of ammonia fuel in its non-catalytic cracking area is reduced.

[0018] Furthermore, when the NO x When the concentration is higher than 200ppm, reduce the air supply volume in the main burner area and increase the air supply volume of the separate overburnt air burner; at the same time, reduce the O2 concentration measured by the SCR inlet flue gas composition analysis device, and reduce the amount of fuel ammonia entering the furnace by adjusting and closing the fuel ammonia regulating valve.

[0019] Furthermore, an SCR outlet flue gas sampling device and an SCR outlet flue gas component analysis device connected to the SCR outlet flue gas sampling device are arranged on the flue between the SCR denitrification reactor and the air preheater to analyze NO in the flue gas at the outlet of the SCR denitrification reactor. x content; at the same time, according to the NO x and NH3 concentration, controlling the reduced NH3 flow entering the ammonia injection grid.

[0020] Furthermore, when the NH3 concentration measured by the SCR inlet flue gas component analysis device and the NH3 concentration measured by the SCR outlet flue gas component analysis device both exceed the standard, the fuel ammonia regulating valve and the reduction ammonia regulating valve are closed at the same time.

[0021] The invention discloses a liquid ammonia and coal-fired complementary power generation system and method, which has the following beneficial effects:

[0022] 1) The ammonia gas after liquid ammonia gasification is divided into two paths and sent to the furnace and SCR device respectively, which accelerates the combustion of liquid ammonia in the furnace. Some of the ammonia that is not fully burned and the NO generated during the combustion process in the furnace x Reduction reaction occurs, converting part of NO x The ammonia that escapes to the convection heating surface of the boiler is reduced to N2 and H2O and reacts with NO in the flue gas. x After being fully mixed, it enters the SCR reactor together with the ammonia gas sent from the SCR ammonia spray grid, where a catalytic reduction reaction occurs, thereby reducing the NO xEmissions, but also reduce the ammonia escape problem caused by incomplete combustion of liquid ammonia or ammonia gas in the boiler;

[0023] 2) In the present invention, an ammonia fuel burner is arranged in the furnace, and the grid structure area of ​​the ammonia fuel burner is filled with a catalyst for high-temperature decomposition of ammonia. When liquid ammonia or ammonia gas passes through this area, it absorbs the radiant heat in the furnace and cracks to generate hydrogen and nitrogen. The generated hydrogen has a fast ignition speed, and the high-temperature flame generated after combustion radiates the catalyst area, further promoting the decomposition of ammonia. The ammonia fuel is not all directly sprayed into the furnace. This design method of the present invention can improve the efficiency of the mixed combustion of ammonia fuel and coal powder, which is conducive to the ignition and stable combustion of ammonia fuel.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of a gaseous ammonia and coal-fired complementary power generation system in an embodiment of the present invention is shown;

[0027] Figure 2 A schematic diagram of a liquid ammonia fuel and coal-fired complementary power generation system in an embodiment of the present invention is shown;

[0028] Figure 3a A schematic diagram of the cross-sectional structure of a rectangular ammonia fuel burner with a catalyst filled in the outer region in an embodiment of the present invention is shown; Figure 3b A schematic diagram of the cross-sectional structure of a rectangular ammonia fuel burner with a catalyst filled in the inner region in an embodiment of the present invention is shown;

[0029] Figure 4a The cross-sectional structure diagram of a circular ammonia fuel burner with a catalyst filled in the outer region in an embodiment of the present invention is shown. Figure 4b A schematic diagram of the cross-sectional structure of a circular ammonia fuel burner with an internal area filled with catalyst in an embodiment of the present invention is shown.

[0030] Reference numerals: 1, furnace; 2, main burner; 3, separate overburnt air burner; 4, economizer; 5, SCR inlet flue gas sampling device; 6, SCR inlet flue gas component analysis device; 7, ammonia injection grid; 8, SCR denitration reactor; 9, SCR outlet flue gas sampling device; 10, SCR outlet flue gas component analysis device; 11, air preheater; 12, liquid ammonia storage tank; 13, liquid ammonia pump; 14, gasification device; 15, fuel ammonia shut-off valve; 16, fuel ammonia regulating valve; 17, reduction ammonia shut-off valve; 18, reduction ammonia regulating valve; 19, ammonia fuel burner;

[0031] 20a, rectangular burner ammonia catalytic cracking area; 21a, rectangular burner ammonia non-catalytic cracking area; 22a, circular burner ammonia catalytic cracking area; 23a, circular burner ammonia non-catalytic cracking area. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a liquid ammonia and coal-fired complementary power generation system and method, which reduces the coal consumption of the boiler by gasifying or not gasifying the liquid ammonia and directly sending it to the ammonia fuel burner in the main burner area of ​​the furnace, and burning it together with the pulverized coal, thereby reducing the CO2 emission concentration and total emission of the boiler. The liquid ammonia used for combustion and the liquid ammonia used as a denitrification reducing agent share a set of liquid ammonia storage devices, which are divided into liquid ammonia fuel and gaseous ammonia fuel after gasification and evaporation according to the physical state of the ammonia fuel entering the furnace for combustion. The ammonia fuel is sent to the pulverized coal main burner area in the furnace through the ammonia fuel burner, mixed with the pulverized coal and burned, and its air distribution comes from the hot secondary air.

[0034] One aspect of the embodiments of the present invention provides a gaseous ammonia and coal-fired complementary power generation system, such as Figure 1 Another aspect of the present invention provides a liquid ammonia fuel and coal-fired complementary power generation system, such as Figure 2 shown. Figure 1 and Figure 2In the invention, the power generation system includes a furnace 1, a main burner 2 and a separated overburnt air burner 3 arranged inside the furnace 1, and an economizer 4, an ammonia injection grid 7, an SCR denitration reactor 8 and an air preheater 11 are arranged in sequence in the tail flue connected to the flue at the outlet of the furnace 1. An ammonia fuel burner 19 is arranged in the area of ​​the main burner 2; the ammonia injection grid 7 is arranged on the inlet flue of the SCR denitration reactor 8; an SCR inlet flue gas sampling device 5 is arranged on the flue between the outlet of the economizer 4 and the ammonia injection grid 7, and an SCR inlet flue gas component analysis device 6 is connected to the SCR inlet flue gas sampling device 5; the SCR inlet flue gas component analysis device 6 is used for online real-time measurement and display of the flue gas components after the mixed combustion of pulverized coal and ammonia fuel in the area of ​​the main burner 2 in the furnace 1, and the flue gas components are CO, O2, NO x 、NH3. An SCR outlet flue gas sampling device 9 is provided on the flue between the SCR denitration reactor 8 and the air preheater 11, and an SCR outlet flue gas component analysis device 10 is connected to the SCR outlet flue gas sampling device 9. The SCR outlet flue gas component analysis device 10 is used to monitor the denitration flue gas components at the outlet of the SCR denitration reactor 8 in real time, mainly including O2, NO x and NH3 concentration.

[0035] Figure 1 and Figure 2 In the power generation system, the ammonia supply device is further connected to the ammonia fuel burner 19 and the ammonia injection grid 7. The ammonia supply device comprises a liquid ammonia storage tank 12, a liquid ammonia pump 13 and a gasification device 14 which are connected in sequence. Figure 1 and Figure 2 The systems shown differ in the physical state of the ammonia entering the ammonia burner 19, whether it is a gas or a liquid.

[0036] Figure 1 In the process, the liquid ammonia stored in the liquid ammonia storage tank 12 is pressurized and sent to the gasification device 14 by the liquid ammonia pump 13, and the liquid ammonia is heated from liquid to gas by the heating effect of the gasification device 14. The gasification device 14 has two outlets, and the first outlet is connected to the ammonia fuel burner 19 through the fuel ammonia shut-off valve 15 and the fuel ammonia regulating valve 16 in sequence, and a part of the gaseous ammonia is sent to the ammonia fuel burner 19. The second outlet of the gasification device 14 is connected to the ammonia injection grid 7 through the reduction ammonia shut-off valve 17 and the reduction ammonia regulating valve 18 in sequence, and the other part of the gaseous ammonia is sprayed into the ammonia injection grid 7.

[0037] Figure 2In the embodiment, the ammonia supply device includes a liquid ammonia pump 13 connected to a liquid ammonia storage tank 12 and a gasification device 14. The outlet of the liquid ammonia pump 13 is divided into two routes, the first outlet of which is connected to the gasification device 14, and the outlet of the gasification device 14 is connected to the ammonia injection grid 7 through a reduction ammonia shut-off valve 17 and a reduction ammonia regulating valve 18 in sequence, so that the liquid ammonia is gasified into gaseous ammonia and transported to the ammonia injection grid 7. The second outlet of the liquid ammonia pump 13 is connected to the ammonia fuel burner 19 through a fuel ammonia shut-off valve 15 and a fuel ammonia regulating valve 16 in sequence, so that the liquid ammonia pressurized by the liquid ammonia pump 13 is directly transported to the ammonia fuel burner 19.

[0038] The ammonia fuel burner 19 is provided with an inner and outer two-layer structure, one of which is a hollow structure and the other is a grid structure, and the grid structure is filled with a catalyst that can catalytically crack ammonia at high temperature. When liquid ammonia or gaseous ammonia passes through the grid structure area, it absorbs the radiation heat of the furnace 1 and cracks to generate hydrogen and nitrogen. The generated hydrogen has a fast ignition speed, and the high-temperature flame generated after combustion radiates the catalyst area, further promoting the decomposition of ammonia.

[0039] The cross-sectional shape of the ammonia fuel burner 19 can be divided into two shapes: rectangular and circular. The schematic diagram of the cross-sectional structure of the rectangular ammonia fuel burner is shown in FIG. Figure 3a , 3b As shown, the cross-sectional structure diagram of the circular ammonia fuel burner is as follows Figure 4a , 4b shown. Figure 3a and Figure 3b According to the different filling positions of the catalytic cracking catalyst, it is divided into external area filling and internal area filling. Figure 3a In the embodiment, the catalyst filling position for catalytic cracking of ammonia is located at the rectangular burner catalytic cracking region 20a, that is, Figure 3a The outer area of ​​the grid structure in the hollow structure is the rectangular burner ammonia non-catalytic cracking area 21a. Figure 3b In the embodiment, the catalyst filling position for catalytic cracking of ammonia is in the rectangular burner catalytic cracking region 20a, that is, Figure 3b The gridded internal area in the hollow structure is the rectangular burner ammonia non-catalytic cracking area 21a. Figure 4a In the embodiment, the catalyst filling position for catalytic cracking of ammonia is located at the catalytic cracking region 22a of the circular burner, that is, Figure 4a The outer area of ​​the grid structure in the hollow structure is the circular burner ammonia non-catalytic cracking area 23a. Figure 4b In the embodiment, the catalyst filling position for catalytic cracking of ammonia is in the circular burner catalytic cracking region 22a of ammonia, that is, Figure 4b The gridded internal area in the hollow structure and the external area of ​​the hollow structure are the circular burner ammonia non-catalytic cracking area 23a.

[0040] The rectangular cross-section is suitable for direct current pulverized coal burner boilers, which is convenient for installation and arrangement, and is easy to combine with the rectangular pulverized coal burner and its secondary air nozzle. During the combustion process, the ejected ammonia fuel and the secondary air can be quickly mixed, so that the flame formed after the combustion of the ammonia fuel can be stably burned. For the circular cross-section, it is suitable for swirl pulverized coal burner boilers, which is convenient for installation and arrangement, and is easy to combine with the circular pulverized coal burner and its secondary air nozzle. During the combustion process, the ammonia fuel ejected from the circular nozzle and the secondary air can be quickly mixed, ensuring that the flame formed after the combustion of the ammonia fuel can be stably burned. The swirl secondary air can provide sufficient air supply to the ammonia fuel burner 19, ensuring the required air during the ammonia combustion process.

[0041] In the embodiment of the present invention, the gaseous ammonia fuel or liquid ammonia fuel transported by the ammonia supply device does not directly enter the furnace 1, but enters the furnace 1 after being sprayed by the ammonia fuel burner 19. In this process, the gaseous ammonia or liquid ammonia is cracked into hydrogen and nitrogen by using the ammonia catalytic cracking catalyst arranged in the grid structure area of ​​the ammonia fuel burner 19. The high-temperature flame generated by the combustion of hydrogen and ammonia provides high-temperature radiation heat for the cracking of ammonia. The ammonia fuel is mixed and burned with coal powder in the main burner 2. The combustion reaction equation in the main burner 2 area is: O2+NH3→N2+H2O, O2+NH3→NO+H2O, O2+NO→NO2; 2C+O2→2CO, 2CO+O2→2CO2. The main burners 2 are symmetrically distributed on the side wall of the furnace 1, and the separated overburning air burner 3 is located at the upper end of the main burner 2; the ammonia fuel burners 19 are symmetrically distributed in the main burner 2 area. In the embodiment of the present invention, a partial catalytic combustion method is adopted, and a circular or rectangular nozzle is set at the end of the ammonia fuel burner 19. The nozzle is divided into two parts, an inner part and an outer part, one of which is provided with a catalyst for ammonia cracking. When the ammonia fuel that is not easy to burn passes through the end of the ammonia fuel burner 19, under the combined action of the high-temperature flame radiation inside the furnace 1 and the ammonia combustion flame radiation, the fuel ammonia passing through this area undergoes a decomposition reaction and cracks into hydrogen and nitrogen. Hydrogen is easy to ignite and burn, and the combustion speed is fast, which can play the role of combustion-supporting and igniting ammonia fuel. Compared with directly spraying gaseous ammonia fuel or liquid ammonia fuel into the furnace 1, the present invention can better achieve the ignition and stable combustion of ammonia fuel.

[0042] Another aspect of the present invention provides a method for complementary power generation of liquid ammonia and coal, the method using Figure 1 When the system shown is implemented, the specific steps are as follows: the liquid ammonia coming out of the liquid ammonia storage tank 12 is heated by the gasification device 14 under the action of the liquid ammonia pump 13, and the liquid ammonia is heated from liquid to gas; then it is divided into two paths, the first path passes through the reduction ammonia shut-off valve 17 and the reduction ammonia regulating valve 18 in turn, and is sent to the ammonia injection grid 7, after being mixed with the boiler flue gas, it enters the SCR denitration reactor 8, and a denitration reduction reaction occurs to reduce NO in the flue gas.x The second part of the gaseous ammonia enters the catalytic cracking area of ​​the ammonia fuel burner 19 and is cracked into hydrogen and nitrogen; the other part of the gaseous ammonia enters the non-catalytic cracking area of ​​the ammonia fuel burner 19; the two parts of fuel are sent to the furnace 1 together, mixed with the pulverized coal in the main burner 2 area and burned, and then sprayed into the main burner 2 area in the furnace 1 to mix with the pulverized coal and burn together.

[0043] The flue gas after combustion passes through the separation burner 3 to further burn the unburned combustibles and at the same time, part of the generated NO x Reduction generates N2 and controls the NO at the outlet of furnace 1 x The SCR inlet flue gas sampling device 5 provided on the flue between the economizer 4 outlet and the ammonia injection grid 7, and the SCR inlet flue gas component analysis device 6 connected to the SCR inlet flue gas sampling device 5, measure and display the flue gas components (CO, O2, NO x , NH3), can provide feedback for the combustion of ammonia fuel in the furnace 1, guide the furnace 1 to optimize the air distribution, and control the CO and NO in the flue gas in the flue duct at the outlet of the economizer 4. x concentration, thereby achieving optimal combustion of ammonia fuel and pulverized coal inside the furnace, which can both ensure combustion efficiency and control pollutant emissions.

[0044] Specifically, when the NH3 concentration detected by the SCR inlet flue gas component analysis device 6 is higher than 100ppm, it is necessary to increase the air supply volume of the ammonia fuel burner 19 and the secondary air nozzles in the upper and lower areas thereof, and increase the amount of ammonia fuel in the catalytic cracking area of ​​the ammonia fuel burner 19, and correspondingly reduce the amount of ammonia fuel in the non-catalytic cracking area, increase the proportion of ammonia fuel in catalytic cracking combustion, and reduce the proportion of ammonia fuel in non-catalytic cracking. If necessary, adjust and close the fuel ammonia regulating valve 16 to reduce the amount of fuel ammonia entering the furnace 1 until the NH3 concentration detected by the SCR inlet flue gas component analysis device 6 is lower than or equal to 100ppm. When the NOx concentration detected by the SCR inlet flue gas component analysis device 6 is higher than 200ppm, it is necessary to reduce the air supply volume in the main burner 2 area, increase the air supply volume of the separate burnout air burner 3, and reduce the O2 concentration detected by the SCR inlet flue gas component analysis device 6. By adjusting and closing the fuel ammonia regulating valve 16, the amount of fuel ammonia entering the furnace is reduced; when the NH3 concentration detected by the SCR inlet flue gas component analysis device 6 is greater than NO xWhen the concentration is low, it is necessary to adjust and close the fuel ammonia regulating valve 16 to reduce the amount of fuel ammonia entering the furnace 1, increase the amount of ammonia fuel in the catalytic cracking area, and correspondingly reduce the amount of ammonia fuel in the non-catalytic cracking area, increase the proportion of ammonia fuel in catalytic cracking combustion, and reduce the proportion of non-catalytic cracking ammonia fuel, until the NH3 concentration is lower than 100ppm.

[0045] The SCR outlet flue gas sampling device 9 and the SCR outlet flue gas component analysis device 10 connected to the SCR outlet flue gas sampling device 9 are arranged on the flue between the SCR denitration reactor 8 and the air preheater 11 to analyze the component data of the mixed flue gas after denitration, and control the reduced ammonia flow entering the ammonia injection grid 7 according to the component data. At the same time, the corresponding ammonia injection and the combustion of the furnace 1 are adjusted to ensure that the SCR outlet NO x The emission meets environmental protection requirements. When the NH3 concentration measured by the SCR inlet flue gas component analysis device 6 and the NH3 concentration measured by the SCR outlet flue gas component analysis device 10 both exceed the standard, the fuel ammonia regulating valve 16 and the reduction ammonia regulating valve 18 are closed at the same time. The present invention analyzes the NO in the flue gas at the outlet of the SCR denitrification reactor 8 by setting the SCR outlet flue gas component analysis device 10. x content, and at the same time, the NO x and NH3 concentration, calculate the reducing ammonia flow rate required to be input into the ammonia injection grid 7, thereby effectively utilizing the escaped ammonia in the furnace 1, and inject it into the SCR denitration reactor 8 together with the gaseous ammonia provided by the gasification device 14 as a reducing agent for the SCR reaction.

[0046] The power generation method of the present invention utilizes Figure 2 When the device shown is implemented, the difference is that the fuel ammonia is not gasified, but is directly divided into two paths from the outlet of the liquid ammonia pump 13. One path passes through the gasification device 14. After heating and evaporation, the ammonia gas passes through the reduction ammonia shut-off valve 17 and the reduction ammonia regulating valve 18 in turn and enters the ammonia injection grid 7. The other path does not pass through the gasification device 14. After being pressurized by the liquid ammonia pump 13, the liquid fuel ammonia passes through the fuel ammonia shut-off valve 15 and the fuel ammonia regulating valve 16 in turn and is sent to the furnace 1.

[0047] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid ammonia and coal-fired complementary power generation system, the system comprising a furnace (1), a main burner (2) and a separated overburnt air burner (3) arranged in the furnace (1), an economizer (4), an ammonia injection grid (7), an SCR denitrification reactor (8) and an air preheater (11) are arranged in sequence in a tail flue connected to the flue at the furnace (1) outlet, the system being characterized in that: An ammonia fuel burner (19) is arranged in the main burner (2) region; the cross-sectional shape of the ammonia fuel burner (19) is rectangular or circular, and comprises a two-layer structure, one layer being a hollow structure and the other layer being a grid structure; the grid structure of the ammonia fuel burner (19) is a catalyst cracking region, and is filled with a catalyst for catalytic cracking of ammonia; the hollow structure of the ammonia fuel burner (19) is a non-catalytic cracking region; The ammonia injection grid (7) is arranged on the inlet flue of the SCR denitration reactor (8); An SCR inlet flue gas sampling device (5) is provided on the flue between the economizer (4) outlet and the ammonia injection grid (7), and the SCR inlet flue gas sampling device (5) is connected to an SCR inlet flue gas component analysis device (6); An SCR outlet flue gas sampling device (9) is provided on the flue between the SCR denitration reactor (8) and the air preheater (11), and the SCR outlet flue gas sampling device (9) is connected to an SCR outlet flue gas component analysis device (10); The system further comprises an ammonia supply device, which is respectively connected to the ammonia fuel burner (19) and the ammonia injection grid (7).

2. The system according to claim 1, characterized in that The ammonia supply device comprises a liquid ammonia storage tank (12), a liquid ammonia pump (13) and a gasification device (14) which are connected in sequence, wherein: The outlet of the gasification device (14) is divided into two outlets. The first outlet of the gasification device (14) is connected to the ammonia fuel burner (19) via a fuel ammonia shut-off valve (15) and a fuel ammonia regulating valve (16) in sequence; The second outlet of the gasification device (14) is connected to the ammonia injection grid (7) via a reduction ammonia shut-off valve (17) and a reduction ammonia regulating valve (18) in sequence.

3. The system according to claim 1, characterized in that The ammonia supply device comprises a liquid ammonia pump (13) connected to a liquid ammonia storage tank (12) and a gasification device (14), wherein: The outlet of the liquid ammonia pump (13) is divided into two paths, the first outlet of the liquid ammonia pump (13) is connected to the gasification device (14), and the outlet of the gasification device (14) is connected to the ammonia injection grid (7) via a reduction ammonia shut-off valve (17) and a reduction ammonia regulating valve (18) in sequence; The second outlet of the liquid ammonia pump (13) is connected to the ammonia fuel burner (19) via a fuel ammonia shut-off valve (15) and a fuel ammonia regulating valve (16) in sequence.

4. The system according to claim 1, 2 or 3, characterized in that: The main burners (2) are symmetrically distributed on the side wall of the furnace (1); the separated overfire air burners (3) are located at the upper end of the main burners (2); and the ammonia fuel burners (19) are symmetrically distributed in the area of ​​the main burners (2).

5. A method for complementary power generation of liquid ammonia and coal, the method utilizing the system according to any one of claims 1, 2, and 4, characterized in that: The method steps are as follows: Liquid ammonia pumped out from the liquid ammonia storage tank (12) by a liquid ammonia pump (13) is heated into gaseous ammonia by a gasification device (14); The gaseous ammonia enters the ammonia fuel burner (19) through the first outlet of the gasification device (14) and the fuel ammonia shut-off valve (15) and the fuel ammonia regulating valve (16) in sequence, and is mixed with the pulverized coal in the main burner (2) area in the furnace (1) for combustion; the flue gas after combustion continues to burn through the separation overburnt air burner (3) and enters the SCR denitration reactor (8) through the economizer (4); The gaseous ammonia enters the ammonia injection grid (7) through the second outlet of the gasification device (14) through the reduction ammonia shut-off valve (17) and the reduction ammonia regulating valve (18), is mixed with the flue gas after combustion, and enters the SCR denitration reactor (8).

6. The method according to claim 5, characterized in that The NO after the pulverized coal mixed combustion is analyzed by an SCR inlet flue gas sampling device (5) connected to the flue between the economizer (4) outlet and the ammonia injection grid (7), and an SCR inlet flue gas component analysis device (6) connected to the SCR inlet flue gas sampling device (5). x concentration and NH3 concentration.

7. The method according to claim 6, characterized in that When the NH3 concentration measured by the SCR inlet flue gas composition analysis device (6) is greater than NO x When the concentration is lower than 100 ppm, the opening of the fuel ammonia regulating valve (16) is closed to reduce the amount of fuel ammonia entering the furnace 1, increase the amount of ammonia fuel in the catalytic cracking area of ​​the ammonia fuel burner (19), and reduce the amount of ammonia fuel in the non-catalytic cracking area of ​​the ammonia fuel burner (19) until the NH3 concentration is lower than 100 ppm.

8. The method according to claim 6, characterized in that When the NH3 concentration measured by the SCR inlet flue gas component analysis device (6) is higher than 100 ppm, the air supply volume of the ammonia fuel burner (19) and the secondary air nozzles in the upper and lower regions thereof is increased; at the same time, the amount of ammonia fuel in the catalytic cracking region is increased, and the amount of ammonia fuel in the non-catalytic cracking region is reduced.

9. The method according to claim 7 or 8, characterized in that: An SCR outlet flue gas sampling device (9) and an SCR outlet flue gas component analysis device (10) connected to the SCR outlet flue gas sampling device (9) are provided on the flue between the SCR denitration reactor (8) and the air preheater (11) to analyze NO in the flue gas at the outlet of the SCR denitration reactor (8). x content; at the same time, according to the NO x and NH3 concentration, and controls the reduced NH3 flow rate entering the ammonia injection grid (7).

Images