Ammonia production system and method for denitration system of thermal power plant

Abstract

The invention discloses an ammonia production system and method for a denitration system of a thermal power plant, and the ammonia production system comprises a unit steam extraction system, a rotary pyrolysis reactor system, an ammonia gas condensation mixing system, an ammonia injection and control system and a supercooled water recovery system, a heat release side outlet of the rotary pyrolysis reactor system is communicated with a return water low-pressure heater heat exchanger in a thermal power plant denitration system through a cold water recovery system, a pyrolysis gas outlet of the rotary pyrolysis reactor system is communicated with an inlet of an ammonia gas condensation mixing system, and an outlet of the ammonia gas condensation mixing system is communicated with an inlet of an ammonia injection and control system. According to the system and method, efficient coupling of ammonium bicarbonate pyrolysis and thermal power generating unit steam turbine steam extraction can be achieved, the ammonia production efficiency is improved, and efficient utilization of energy is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas denitration in thermal power plants, and relates to an ammonia production system and method for a denitration system in a thermal power plant. Background Art

[0002] With the increasingly stringent environmental protection policies, the efficiency and safety requirements of denitrification systems in thermal power plants are constantly increasing. Selective catalytic reduction (SCR) denitrification technology is widely used due to its high efficiency, but the selection and use of its reducing agent still faces many challenges.

[0003] At present, the commonly used reducing agents in the SCR denitrification system of thermal power plants mainly include liquid ammonia, ammonia water and urea. However, these traditional reducing agents have their own limitations: 1) The preparation cost of liquid ammonia is low, but as a Class B dangerous goods stipulated by the state, it has major safety hazards and strict transportation and storage requirements. 2) Ammonia water is safer than liquid ammonia, but it is still a dangerous chemical, corrosive, and has high transportation costs and requires large storage equipment. 3) Urea is safer, but the system investment and operating costs are high, energy consumption is large, and it is easy to crystallize in low temperature environments.

[0004] Therefore, the development of new safe, efficient and low-cost reducing agent preparation methods has become an urgent need in the industry. In recent years, ammonium bicarbonate has attracted widespread attention as a potential alternative raw material. Ammonium bicarbonate is the second largest nitrogen fertilizer after urea, with a wide source and relatively low price. More importantly, ammonium bicarbonate begins to decompose and produce ammonia at around 100°C, which makes it possible to use it in the preparation of denitrification reducing agents.

[0005] However, how to efficiently convert ammonium bicarbonate into ammonia and organically integrate it with the existing system of thermal power plants is still a technical problem that needs to be solved. In particular, how to make full use of the heat source within the unit plant and achieve efficient use of energy is one of the key directions of current research. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an ammonia production system and method for a denitrification system of a thermal power plant, which can achieve efficient coupling of pyrolysis of ammonium bicarbonate and steam extraction of a thermal power unit steam turbine, improve ammonia production efficiency, and achieve efficient utilization of energy.

[0007] To achieve the above-mentioned purpose, the present invention discloses an ammonia production system for a denitration system of a thermal power plant, comprising a unit steam extraction system, a rotary pyrolysis reactor system, an ammonia condensation mixing system, an ammonia injection and control system and a supercooled water recovery system, wherein the outlet of the unit steam extraction system is connected to the heat release side inlet of the rotary pyrolysis reactor system, the heat release side outlet of the rotary pyrolysis reactor system is connected to a return water low-pressure heat exchanger in the denitration system of the thermal power plant through a cold water recovery system, the pyrolysis gas outlet of the rotary pyrolysis reactor system is connected to the inlet of the ammonia condensation mixing system, and the outlet of the ammonia condensation mixing system is connected to the inlet of the ammonia injection and control system.

[0008] Furthermore, the steam extraction system of the unit includes a steam extraction port, a steam extraction pipeline, a multi-stage pressure regulating device, a flow regulating valve and a pipeline insulation layer, wherein the steam extraction port is connected to the heat release side inlet of the rotary pyrolysis reactor system through the steam extraction pipeline, and the multi-stage pressure regulating device, the flow regulating valve and the pipeline insulation layer are all arranged on the steam extraction pipeline.

[0009] Furthermore, the rotary pyrolysis reactor system is an externally heated rotary pyrolysis reactor or an internally heated rotary pyrolysis reactor.

[0010] Furthermore, the ammonia condensation and mixing system includes a condenser, a fan and a mixer. The pyrolysis gas outlet of the rotary pyrolysis reactor system is connected to the inlet of the mixer through the condenser and the fan, and the outlet of the mixer is connected to the inlet of the ammonia injection and control system.

[0011] Furthermore, the supercooled water recovery system includes a condensed water collection device and a supercooled water pump. The condensed water output from the heat release outlet of the rotary pyrolysis reactor system and the condensed water generated by the pyrolysis reaction enter the return water low-pressure heat exchanger through the condensed water collection device and the supercooled water pump.

[0012] The present invention discloses an ammonia production method for a denitration system of a thermal power plant, comprising the following steps:

[0013] The steam extracted by the unit's steam extraction system enters the rotary pyrolysis reactor system to release heat to heat the ammonium bicarbonate particles in the rotary pyrolysis reactor system, so that the ammonium bicarbonate particles are pyrolyzed to produce pyrolysis gas, which is condensed by the ammonia condensation and mixing system, mixed with the preheated air, and then sprayed into the flue through the ammonia injection and control system; at the same time, the condensed water output by the rotary pyrolysis reactor system is sent to the return water low-pressure heat exchanger through the cold water recovery system.

[0014] Furthermore, the rotary pyrolysis reactor system is an externally heated rotary pyrolysis reactor or an internally heated rotary pyrolysis reactor.

[0015] Furthermore, it also includes:

[0016] The logarithmic mean temperature difference of the temperature difference at both ends of the rotary pyrolysis reactor system is calculated, the heat exchange area of ​​the rotary pyrolysis reactor system is calculated according to the logarithmic mean temperature difference, and the number and size of the heat exchange tubes in the rotary pyrolysis reactor system are determined according to the heat exchange area of ​​the rotary pyrolysis reactor system.

[0017] Furthermore, the logarithmic mean temperature difference is:

[0018]

[0019] A=Q / (K*ΔT)

[0020]

[0021] Where K is the total heat transfer coefficient, h o is the heat transfer coefficient on the shell side of the heat exchanger, h i is the heat transfer coefficient in the heat transfer tube, b is the thickness of the heat transfer tube / m, A is the total heat transfer area of ​​the heat transfer tube, ΔT is the average heat transfer temperature difference based on the heat exchanger, R i and R o is the thermal resistance of dirt inside and outside the heat transfer tube, λ w is the thermal conductivity of the tube wall.

[0022] Furthermore, the supercooled water recovery system includes a condensed water collection device and a supercooled water pump. The condensed water output from the heat release outlet of the rotary pyrolysis reactor system and the condensed water generated by the pyrolysis reaction enter the return water low-pressure heat exchanger through the condensed water collection device and the supercooled water pump.

[0023] The present invention has the following beneficial effects:

[0024] The ammonia production system and method for the denitration system of a thermal power plant described in the present invention is used in specific operations. Since there are a large number of extraction steam resources in the steam turbine system of the thermal power unit, these extraction steam are usually used for water heating, deaerator heating and other purposes, but some waste heat is still not fully utilized. The present invention innovatively uses the extraction steam (typical parameter range is superheated steam with a pressure of 0.4-0.8MPa and a temperature of 230-300°C) of the connecting pipe of the medium and low pressure cylinder of the unit as a heat source, and deeply integrates it with the pyrolysis process of ammonium bicarbonate. This high-quality heat source provides sufficient thermal energy for the system and realizes the cascade utilization of energy. Using these extraction steam waste heat to pyrolyze ammonium bicarbonate to produce ammonia can not only improve the overall energy utilization efficiency of the unit, but also significantly reduce the cost of ammonia production. It has important theoretical significance and practical application value. This can not only solve the problems of traditional reducing agents, but also improve the overall energy utilization efficiency of thermal power plants, and provide a new technical path for the clean and efficient development of the thermal power industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a structural diagram of the present invention;

[0027] Figure 2 It is a structural diagram of an externally heated rotary pyrolysis reactor;

[0028] Figure 3 This is a structural diagram of an internal heating rotary pyrolysis reactor.

[0029] Among them, 1 is a rotary pyrolysis reactor system, 2 is a fan, 3 is a condenser, 4 is a mixer, and 5 is a supercooling water pump. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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.

[0031] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0032] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0033] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0034] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0035] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions 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, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0038] Embodiment 1

[0039] refer to Figure 1The ammonia production system for the denitration system of a thermal power plant described in the present invention comprises a unit steam extraction system, a rotary pyrolysis reactor system 1, an ammonia condensation mixing system, an ammonia injection and control system and a supercooled water recovery system, wherein the outlet of the unit steam extraction system is connected to the heat release side inlet of the rotary pyrolysis reactor system 1, the heat release side outlet of the rotary pyrolysis reactor system 1 is connected to the return water low-pressure heat exchanger in the denitration system of the thermal power plant through the cold water recovery system, the pyrolysis gas outlet of the rotary pyrolysis reactor system 1 is connected to the inlet of the ammonia condensation mixing system, and the outlet of the ammonia condensation mixing system is connected to the inlet of the ammonia injection and control system.

[0040] Specifically, the unit steam extraction system:

[0041] The present invention closely combines the ammonium bicarbonate pyrolysis device with the steam extraction system of the thermal power unit to fully utilize the high-grade thermal energy in the unit. Specifically, steam is extracted from the intermediate pressure cylinder of the steam turbine through the steam extraction system of the unit. Preferably, intermediate pressure extraction steam at about 260° C. and a pressure of about 0.5 MPa is extracted from the steam turbine of the thermal power unit.

[0042] The steam extraction system of the unit includes a steam extraction port, a steam extraction pipeline, a multi-stage pressure regulating device, a flow regulating valve and a pipeline insulation layer, wherein the steam extraction port is connected to the heat release side inlet of the rotary pyrolysis reactor system 1 through the steam extraction pipeline, and the multi-stage pressure regulating device, the flow regulating valve and the pipeline insulation layer are all arranged on the steam extraction pipeline. When working, the steam parameters are accurately adjusted according to the ammonia production demand through the multi-stage pressure regulating device, and the ammonia production system can be quickly started and stopped by cooperating with the flow regulating valve without affecting the normal operation of the unit.

[0043] Rotary pyrolysis reactor system 1:

[0044] Based on thermal calculation, the ammonia mass flow rate provided by the ammonia production system for a single 300MW unit is about 170kg / h. With an ammonia production of 170kg / h and a conversion rate of 95% as the target, 832kg / h of ammonium bicarbonate raw material is required, fed at normal temperature and pressure. The feed rate of the rotary inlet in the rotary pyrolysis reactor system 1 is 0.832t / h, and the outlet is 0.17t / h, and the average value is G m =0.5t / h. Set the material filling rate to 15% and the material residence time to 20 minutes. Set the cylinder inclination angle to 3° and the cylinder speed to 1r / min. According to the rotary kiln heating device size design formula, the rotary pyrolysis device length L is 6m and the diameter D is 0.75m.

[0045] Specifically, refer to Figure 2 and Figure 3 The rotary pyrolysis reactor system 1 is an external heating rotary pyrolysis reactor or an internal heating rotary pyrolysis reactor.

[0046] Externally heated rotary pyrolysis reactor:

[0047] The solid particles of ammonium bicarbonate are stored in the silo, and when preparing ammonia, they are directly sent from the silo to the inside of the kiln through a conveyor. The medium-pressure steam extraction of the extraction unit provides the heat required for the decomposition of the solid ammonium bicarbonate. By heating the wall of the kiln-type cylinder, the heat is transferred to the solid ammonium bicarbonate particles close to the wall, and then to most of the ammonium bicarbonate particles in the cylinder by heat conduction. The ammonia produced by the decomposition is extracted from the pyrolysis furnace under negative pressure and sent to the SCR reactor after dilution. This implementation method requires additional heat exchange surface and steam flow space outside the rotating cylinder.

[0048] Internal heating rotary pyrolysis reactor:

[0049] The internal heating rotary pyrolysis reactor is provided with a plurality of heat transfer tubes arranged in parallel, the outside of the tubes are filled with ammonium bicarbonate particles, the inside of the tubes is filled with high-temperature flue gas, and the cylinder rotates to make the particles fully contact with the heat transfer tubes, thereby improving the heat transfer efficiency.

[0050] The enthalpy change of the decomposition reaction required for the pyrolysis of ammonium bicarbonate is 167.92 kJ / mol. Taking into account the reaction heat and air temperature rise, the system needs to provide an external heating power of about 900 kW. The steam pressure extracted at the inlet is 5 bar, the inlet temperature is 260 ° C, the outlet pressure is 2 bar, and the steam outlet temperature is 120 ° C. After heating, the steam condenses into saturated water, making full use of the latent heat of condensation of the steam. According to calculations, the required steam volume is about 0.96 t / h.

[0051] First, based on the physical properties of steam and the required total heating power, estimate the total heat transfer area and number of heat transfer tubes.

[0052] The heat transfer coefficient formula for condensation phase change in the horizontal tube is:

[0053]

[0054] Fouling thermal resistance R inside and outside the heat transfer tube i and R o Both are 0.00017179m 2 K / W; thermal conductivity of the tube wall λ w It is 45W / (m·K).

[0055] The overall heat transfer coefficient is:

[0056]

[0057] Among them, h o is the heat transfer coefficient of the shell side of the heat exchanger, and the heat transfer coefficient between the ammonium bicarbonate particles and the heat transfer tube is 500W / (m 2 ·K);h i is the heat transfer coefficient in the heat transfer tube; b is the thickness of the heat transfer tube / m.

[0058] The total heat transfer area of ​​the heat transfer tube is A = Q / (K*ΔT); the average heat transfer temperature difference ΔT based on the heat exchanger is obtained. The average temperature difference is the logarithmic average of the temperature difference at both ends of the heat exchanger, which is called the logarithmic mean temperature difference. The calculation formula of the countercurrent average temperature difference is the same, but the calculation method of the temperature difference at both ends is different. It can be calculated according to the following formula:

[0059]

[0060]

[0061] According to the calculated temperature difference, the required heat exchange area for steam heating is about 25m 2 The size of the selected single heat transfer tube is Φ25×2.5mm in diameter, 5m in length, and 32mm in spacing. The number of heat transfer tubes is calculated based on the heat exchange area. The number of single tubes required for steam heating is 64. A 4-pass tube is used and the tubes are arranged in sequence at a certain angle in the circumferential direction of the rotary device. A maximum of 38 rows of 4-pass tubes can be arranged circumferentially. For the steam heating solution, only 16 rows are needed to meet the heat exchange area requirements. The heat exchange tubes are mainly concentrated in the lower half of the cylinder, which is in full contact with the ammonium bicarbonate particles.

[0062] Ammonia condensation mixing system:

[0063] The ammonia condensation and mixing system includes a condenser 3, a fan 2 and a mixer 4, wherein the condenser 3 is added to reduce the moisture content in the product ammonia and improve the ammonia separation efficiency. After the product gas leaves the rotary pyrolysis reactor system 1, it is sent to the mixer 4 through the condenser 3 and the fan 2 to be diluted with the hot dilution air, and then sent to the denitrification flue to participate in the denitrification reaction.

[0064] Ammonia injection and control system:

[0065] An ammonia injection grid is set up in accordance with the requirements of precise ammonia injection modification, equipped with an ammonia flow precision control device to achieve on-demand ammonia injection, equipped with an intelligent PID control algorithm to optimize system operating parameters and achieve automatic control of the ammonia injection process.

[0066] Subcooled water recovery system:

[0067] The supercooled water recovery system includes a condensed water collection device and a supercooled water pump 5. The condensed water output from the heat release outlet of the rotary pyrolysis reactor system 1 and the condensed water generated by the pyrolysis reaction enter the return water low-pressure heat exchanger through the condensed water collection device and the supercooled water pump 5 to improve the overall thermal efficiency, realize the recycling of water resources, and further optimize the economy and environmental protection of the ammonia production system.

[0068] Embodiment 2

[0069] The ammonia production method for a thermal power plant denitration system of the present invention comprises the following steps:

[0070] The steam extracted by the unit's steam extraction system enters the rotary pyrolysis reactor system 1 to release heat, so as to heat the ammonium bicarbonate particles in the rotary pyrolysis reactor system 1, so that the ammonium bicarbonate particles are pyrolyzed to produce pyrolysis gas, which is condensed by the ammonia condensation and mixing system, mixed with the preheated air, and then sprayed into the flue through the ammonia injection and control system; at the same time, the condensed water output by the rotary pyrolysis reactor system 1 is sent to the return water low-pressure heat exchanger through the cold water recovery system.

[0071] Compared with the prior art, the present invention has the following characteristics:

[0072] 1. The present invention makes full use of the waste heat of steam extraction from the steam turbine of the thermal power unit, significantly reduces the energy consumption of ammonia production, and improves the overall thermal efficiency of the unit by about 2-3%.

[0073] 2. The present invention adopts solid pyrolysis, which avoids the heat absorption of solution evaporation, further reduces energy consumption, and has high thermal efficiency.

[0074] 3. The system of the present invention has simple equipment and occupies only 1 / 3 of the floor space of the traditional ammonia preparation system, and the investment cost is reduced by about 40%.

[0075] 4. The raw material cost of the present invention is low, and the operating cost is reduced by about 30% compared with the traditional ammonia production scheme.

[0076] 5. The present invention improves the safety of the denitration system and completely eliminates the risk of using dangerous chemicals such as liquid ammonia.

[0077] 6. The pyrolysis reaction temperature of the present invention is low (110-150° C.), the equipment is less corrosive, and the service life of the equipment is extended.

[0078] 7. The system of the present invention has a fast response speed and can adjust the ammonia production in real time according to the unit load and denitrification demand within 15 minutes.

[0079] 8. The present invention adopts medium-pressure extraction steam as the heat source, and the temperature is easier to control, thereby improving the stability and controllability of the ammonia production process.

[0080] 9. The system of the present invention can realize rapid start and stop (start time <30min), does not affect the normal operation of the unit, and enhances the peak load regulation capability of the unit.

[0081] 10. The pyrolysis device and automatic control system of the present invention realize a high degree of automation of the ammonia production process, and the number of operators can be reduced from 3 people / shift to 1 person / shift, thereby reducing the difficulty of operation and labor costs.

[0082] 11. The system of the present invention operates stably, with an annual operating time of more than 8,000 hours, which greatly improves the reliability of the denitrification system.

[0083] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0084] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An ammonia production system for a thermal power plant denitrification system, characterized in that: The invention comprises a unit steam extraction system, a rotary pyrolysis reactor system (1), an ammonia condensation mixing system, an ammonia injection and control system and a supercooled water recovery system, wherein the outlet of the unit steam extraction system is connected to the heat release side inlet of the rotary pyrolysis reactor system (1), the heat release side outlet of the rotary pyrolysis reactor system (1) is connected to the return water low-pressure heat exchanger in the denitration system of the thermal power plant through the cold water recovery system, the pyrolysis gas outlet of the rotary pyrolysis reactor system (1) is connected to the inlet of the ammonia condensation mixing system, and the outlet of the ammonia condensation mixing system is connected to the inlet of the ammonia injection and control system.

2. The ammonia production system for a thermal power plant denitration system according to claim 1, characterized in that: The steam extraction system of the unit comprises a steam extraction port, a steam extraction pipeline, a multi-stage pressure regulating device, a flow regulating valve and a pipeline insulation layer, wherein the steam extraction port is connected to the heat release side inlet of the rotary pyrolysis reactor system (1) through the steam extraction pipeline, and the multi-stage pressure regulating device, the flow regulating valve and the pipeline insulation layer are all arranged on the steam extraction pipeline.

3. The ammonia production system for a thermal power plant denitration system according to claim 1, characterized in that: The rotary pyrolysis reactor system (1) is an externally heated rotary pyrolysis reactor or an internally heated rotary pyrolysis reactor.

4. The ammonia production system for a thermal power plant denitrification system according to claim 1, characterized in that: The ammonia condensation and mixing system comprises a condenser (3), a fan (2) and a mixer (4); the pyrolysis gas outlet of the rotary pyrolysis reactor system (1) is connected to the inlet of the mixer (4) via the condenser (3) and the fan (2); and the outlet of the mixer (4) is connected to the inlet of the ammonia injection and control system.

5. The ammonia production system for a thermal power plant denitration system according to claim 1, characterized in that: The supercooled water recovery system comprises a condensed water collection device and a supercooled water pump (5), and the condensed water output from the heat release outlet of the rotary pyrolysis reactor system (1) and the condensed water generated by the pyrolysis reaction enter the return water low-pressure heat exchanger through the condensed water collection device and the supercooled water pump (5).

6. A method for producing ammonia for a denitration system of a thermal power plant, characterized in that: The ammonia production system for a thermal power plant denitrification system according to claim 1 comprises the following steps: The steam extracted by the unit's steam extraction system enters the rotary pyrolysis reactor system (1) to release heat, thereby heating the ammonium bicarbonate particles in the rotary pyrolysis reactor system (1), causing the ammonium bicarbonate particles to pyrolyze and generate pyrolysis gas. The pyrolysis gas is condensed by an ammonia condensation and mixing system, mixed with preheated air, and then sprayed into the flue through an ammonia injection and control system. At the same time, condensed water output from the rotary pyrolysis reactor system (1) is sent to the return water low-pressure heat exchanger through a cold water recovery system.

7. The method for producing ammonia for a denitration system of a thermal power plant according to claim 6, characterized in that: The rotary pyrolysis reactor system (1) is an externally heated rotary pyrolysis reactor or an internally heated rotary pyrolysis reactor.

8. The method for producing ammonia for a denitration system of a thermal power plant according to claim 6, characterized in that: Also includes: The logarithmic mean temperature difference of the temperature difference at both ends of the rotary pyrolysis reactor system (1) is calculated, the heat exchange area of ​​the rotary pyrolysis reactor system (1) is calculated based on the logarithmic mean temperature difference, and the number and size of the heat exchange tubes in the rotary pyrolysis reactor system (1) are determined based on the heat exchange area of ​​the rotary pyrolysis reactor system (1).

9. The method for producing ammonia for a denitration system of a thermal power plant according to claim 8, characterized in that: The supercooled water recovery system comprises a condensed water collection device and a supercooled water pump (5), and the condensed water output from the heat release outlet of the rotary pyrolysis reactor system (1) and the condensed water generated by the pyrolysis reaction enter the return water low-pressure heat exchanger through the condensed water collection device and the supercooled water pump (5).

10. The method for producing ammonia for a denitration system of a thermal power plant according to claim 8, characterized in that: The ammonia condensation and mixing system comprises a condenser (3), a fan (2) and a mixer (4); the pyrolysis gas outlet of the rotary pyrolysis reactor system (1) is connected to the inlet of the mixer (4) via the condenser (3) and the fan (2); and the outlet of the mixer (4) is connected to the inlet of the ammonia injection and control system.

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