Denitration ammonia and cyanuric acid co-production equipment and control method thereof

Abstract

The invention discloses denitration ammonia and cyanuric acid co-production equipment and a control method thereof, and belongs to the technical field of chemical production, the denitration ammonia and cyanuric acid co-production equipment comprises: a reaction system for pyrolyzing urea; the flow distribution system is connected with the reaction system and is used for controlling the flow of ammonia gas input into the ammonia reduction denitration system; wherein the flow distribution system comprises an ammonia gas output subsystem and an ammonia gas storage subsystem, and the ammonia gas storage subsystem is used for storing ammonia gas in a gas main pipeline when the ammonia production amount of the reaction system is greater than the ammonia demand amount of the ammonia reduction denitration system; when the ammonia production amount of the reaction system is smaller than the ammonia demand amount of the ammonia reduction denitration system, the stored ammonia gas is output into the ammonia reduction denitration system; through the design of the ammonia gas output subsystem and the ammonia gas storage system, the technical problem that the regulation and control difficulty of the ammonia production rate of equipment in the related technology is large is solved, and the situation of secondary pollution caused by ammonia escape is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, and more specifically, to a denitrification ammonia and cyanuric acid co-production device and a control method thereof. Background Art

[0002] In coal-fired power plants that generate electricity by burning fuel, the exhaust gas from the boiler needs to be purified before being discharged into the atmosphere. The SNCR and SCR technologies commonly used in coal-fired power plants have basically the same principle of achieving flue gas denitrification, which is to selectively react with nitrogen oxides (mainly NO and NO2) in the flue gas under reducing atmosphere conditions through denitrification agents, ultimately generating harmless N2 and H2O. At present, most coal-fired power plants use urea hydrolysis or urea pyrolysis to produce amino-containing reducing agents. The energy consumption of urea pyrolysis to produce ammonia is high, the urea conversion rate is low, and during the operation of the ammonia production system, the urea hydrolyzer, pipelines, and valves are easily corroded and blocked, or the ammonia production system is shut down, increasing the operating cost. The process of producing cyanuric acid from urea produces ammonia gas, and the water vapor content in the produced gas is extremely low, which has little corrosion to the equipment. Therefore, the co-production process of ammonia and cyanuric acid for the preparation of denitrification reducing agent can reduce the risk of equipment corrosion and extend the service life of the equipment. In addition, the high-value by-product cyanuric acid is produced, which is conducive to reducing the cost of ammonia production. However, in the current process of producing cyanuric acid from urea, there are technical problems such as low ammonia concentration and difficulty in controlling the ammonia production rate. When the flue gas load from the boiler changes, it is difficult to make adaptive adjustments to the ammonia production of the equipment according to the ammonia required for denitrification. This will not only directly affect the denitrification efficiency, but in severe cases will cause ammonia escape and secondary pollution, leading to ash accumulation and blockage in the downstream air preheater, resulting in increased pressure loss and low-temperature corrosion. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems of low ammonia concentration and difficulty in regulating ammonia production rate in the existing process of preparing cyanuric acid from urea, and to propose a denitrification ammonia and cyanuric acid co-production equipment and a control method thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: The first aspect of the present invention provides a denitrification ammonia and cyanuric acid co-production device, the denitrification ammonia and cyanuric acid co-production device is connected to an ammonia reduction denitrification system, and the denitrification ammonia and cyanuric acid co-production device comprises: a reaction system, the reaction system is used to pyrolyze urea, output ammonia gas produced by the reaction, and collect cyanuric acid produced by the reaction; A flow distribution system, wherein the flow distribution system is connected to the reaction system via a gas main pipeline, and the flow distribution system is used to adjust the flow of ammonia gas input into the ammonia reduction denitration system; Wherein, the flow distribution system comprises: an ammonia output subsystem, the ammonia output subsystem being used to transport the ammonia output from the reaction system to an ammonia reduction denitration system; An ammonia storage subsystem is used to store the ammonia in the gas main pipeline when the ammonia production of the reaction system is greater than the ammonia demand of the ammonia reduction denitrification system; and to output the stored ammonia to the ammonia reduction denitrification system when the ammonia production of the reaction system is less than the ammonia demand of the ammonia reduction denitrification system.

[0005] Further, the reaction system comprises: a molten urea storage tank; A heater, wherein the heater is disposed in the molten urea storage tank; A reactor, wherein the reactor is provided with a gas outlet and a solid outlet, the gas outlet is connected to the gas inlet of the gas main pipeline, and the reactor is connected to the molten urea storage tank; A separator is arranged on the gas main pipeline and is used to capture solid particles of cyanuric acid in ammonia.

[0006] Furthermore, the reaction system further comprises: an atomizer, which is arranged inside the reactor and is used to atomize the molten urea output from the molten urea storage tank; The reactor is connected to the molten urea storage tank via a liquid pipeline, and the discharge end of the liquid pipeline is connected to the atomizer; a molten urea delivery pump is provided on the liquid pipeline.

[0007] Furthermore, the ammonia output subsystem includes: a first ammonia branch pipeline, wherein the gas inlet of the first ammonia branch pipeline is connected to the gas main pipeline; a first induced draft fan, the first induced draft fan is connected to the first ammonia branch pipeline, and is used to pump ammonia in the first ammonia branch pipeline into the ammonia reduction denitration system; A first valve is connected to the first ammonia branch pipeline and is located at the front end of the air inlet of the first induced draft fan.

[0008] Furthermore, the ammonia storage subsystem includes: A second ammonia branch pipeline, wherein the gas inlet of the second ammonia branch pipeline is connected to the gas main pipeline; the second ammonia branch pipeline is provided with: a second induced draft fan, the second induced draft fan being used to extract ammonia gas from the gas main pipeline; a second valve, the second valve being located at a front end of an air inlet of the second induced draft fan; A cooler, located at the rear end of the air outlet of the second induced draft fan, for cooling the ammonia gas output by the second induced draft fan; A compressor, the compressor is connected to the cooler and is used to compress the cooled ammonia; an ammonia storage tank, the ammonia storage tank being connected to the compressor and being used to store compressed ammonia; a third induced draft fan, the third induced draft fan being used to pump ammonia gas in the ammonia storage tank into an ammonia reduction denitration system; A third valve is located at a front end of an air inlet of the third induced draft fan.

[0009] A second aspect of the present invention provides a method for controlling a denitrification ammonia and cyanuric acid co-production device, which uses the denitrification ammonia and cyanuric acid co-production device described in any one of the first aspects, and comprises the following steps: S1: heating molten urea storage tank; S2: judging whether the molten urea storage tank meets the molten urea storage conditions based on the internal temperature value of the molten urea storage tank and the first temperature threshold interval; S3: introducing urea into the molten urea storage tank and heating the reactor; S4: judging whether the environment inside the reactor meets the urea thermal decomposition conditions based on the internal temperature value of the reactor and the second temperature threshold interval; S5: atomizing the molten urea into liquid particles, and transporting them into a reactor to react and generate ammonia and cyanuric acid; S6: Collect cyanuric acid solid particles, and control the flow distribution system to distribute the flow of ammonia in the gas main pipeline, and output the distributed ammonia to the ammonia injection grid of the ammonia reduction denitrification system.

[0010] Further, judging whether the molten urea storage tank meets the molten urea storage condition based on the internal temperature value of the molten urea storage tank and the first temperature threshold interval includes: The internal temperature value of the molten urea storage tank is obtained and compared with the first temperature threshold interval; if the internal temperature value of the molten urea storage tank does not match the first temperature threshold interval, the internal temperature value of the molten urea storage tank is adjusted by the heater until the internal temperature value of the molten urea storage tank is within the first temperature threshold interval, and then step S3 is entered.

[0011] Further, based on the internal temperature value of the reactor and the second temperature threshold interval, judging whether the internal environment of the reactor meets the urea pyrolysis condition includes: The internal temperature value of the reactor is obtained and compared with the second temperature threshold interval; if the internal temperature value of the reactor does not match the second temperature threshold interval, the reactor is kept heated until the internal temperature value of the reactor is in the second temperature threshold interval, and then step S5 is entered.

[0012] Furthermore, in step S6, the flow distribution system is controlled to distribute the flow of ammonia gas in the gas main pipeline, including: The denitrification state of the ammonia reduction denitrification system is determined based on the ammonia production from the thermal decomposition of molten urea in the current reactor and the ammonia demand for denitrification of the ammonia reduction denitrification system under the current operating conditions of the boiler unit.

[0013] Furthermore, based on the ammonia production of molten urea pyrolysis in the current reactor and the ammonia demand for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit, the denitration state of the ammonia reduction denitration system is judged, including: The ammonia production from the pyrolysis of molten urea in the current reactor is obtained, and compared with the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit; if the ammonia production from the pyrolysis of molten urea in the current reactor is greater than the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit, it is determined that the ammonia reduction denitration system is in an ammonia escape state; when the ammonia reduction denitration system is in an ammonia escape state, the ammonia flow rate from the gas main pipeline to the ammonia output subsystem is controlled to be reduced; the ammonia flow rate from the gas main pipeline to the ammonia storage subsystem is increased, and the ammonia entering the ammonia storage subsystem is stored in the ammonia storage subsystem; If the ammonia production from the thermal decomposition of molten urea in the current reactor is less than the ammonia required for denitrification by the ammonia reduction denitrification system under the current operating conditions of the boiler unit, it is judged that the ammonia reduction denitrification system is in a low-efficiency denitrification state; when the ammonia reduction denitrification system is in a low-efficiency denitrification state, the flow distribution system is controlled so that the ammonia in the gas main pipeline is output to the ammonia reduction denitrification system through the ammonia output subsystem; and the ammonia stored in the ammonia storage subsystem is output to the ammonia reduction denitrification system.

[0014] The beneficial effects of the present invention are as follows: the flow distribution system of the present application can utilize the ammonia storage tank to store part of the ammonia in the gas main pipeline when the ammonia production of the reaction system is greater than the ammonia demand of the ammonia reduction denitrification system through the design of the ammonia output subsystem and the ammonia storage system, thereby reducing the ammonia flow rate input into the ammonia output subsystem, and further reducing the ammonia flow rate input into the ammonia reduction denitrification system by the ammonia output subsystem; when the ammonia production of the reaction system is less than the ammonia demand of the ammonia reduction denitrification system, the ammonia in the ammonia storage tank and the ammonia in the ammonia output subsystem are input into the ammonia reduction denitrification system together, thereby ensuring the ammonia supply capacity of the ammonia and cyanuric acid co-production equipment for denitrification; the technical problem of the difficulty in regulating the ammonia production rate of the equipment in the related art is solved, and the occurrence of secondary pollution caused by ammonia escape is effectively avoided; The reaction system of the present application is provided with an atomizer and a separator, which can not only ensure the conversion rate of molten urea and the yield of ammonia, but also the high-value by-product cyanuric acid produced by the reaction is beneficial to reducing the cost of ammonia production; in the process of transporting ammonia from the reaction system to the flow distribution system, the solid particles of cyanuric acid carried in the ammonia are captured and collected, on the one hand, to effectively ensure the output of cyanuric acid; on the other hand, it can prevent the particles from entering the flow distribution system and causing wear and corrosion to the equipment and pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an overall schematic diagram of a denitrification ammonia and cyanuric acid co-production device provided in an embodiment of the present invention.

[0016] The markings in the figure are as follows: 1. Reaction system; 11. Gas main pipeline; 12. Molten urea storage tank; 13. Heater; 14. Reactor; 15. Atomizer; 16. Liquid pipeline; 161. Molten urea delivery pump; 17. Separator; 2. Traffic distribution system; 21. Ammonia output subsystem; 211. First ammonia branch pipeline; 212. First valve; 213. First induced draft fan; 22. Ammonia storage subsystem; 221. Second ammonia branch pipeline; 222. Second valve; 223. Second induced draft fan; 224. Cooler; 225. Compressor; 226. Ammonia storage tank; 227. Third valve; 228. Third induced draft fan. DETAILED DESCRIPTION

[0017] 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 only 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.

[0018] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0019] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] See also Figure 1 The embodiment of the present application shown provides a denitrification ammonia and cyanuric acid co-production equipment, which is usually connected to an ammonia reduction denitrification system. It should be noted that the ammonia reduction denitrification system in the technical solution of the present application can be an SNCR denitrification system (i.e., a selective non-catalytic reduction denitrification system) or an SCR denitrification system (i.e., a selective catalytic reduction denitrification system). In actual applications, the ammonia gas produced by the denitrification ammonia and cyanuric acid co-production equipment is first transported to the ammonia injection grid of the ammonia reduction denitrification system, and then sprayed into the reaction device of the ammonia reduction denitrification system through the ammonia injection grid. The ammonia gas is mixed with the flue gas in the reaction device and reacted to achieve the reduction and removal of NOx in the flue gas.

[0022] The ammonia and cyanuric acid co-production equipment for denitrification includes: a reaction system 1 and a flow distribution system 2; wherein the reaction system 1 is used to thermally decompose urea, and output ammonia produced by the reaction, and collect cyanuric acid produced by the reaction; the flow distribution system 2 is connected to the reaction system 1 through a gas main pipeline 11; when the ammonia and cyanuric acid co-production equipment for denitrification of the present application supplies ammonia to the ammonia reduction denitrification system, the ammonia output by the reaction system 1 is transported to the flow distribution system 2 through the gas main pipeline 11, and further, the flow distribution system 2 controls the ammonia flow rate input to the ammonia reduction denitrification system according to the actual ammonia demand of the ammonia reduction system.

[0023] More specifically, the reaction system 1 includes: a molten urea storage tank 12, a heater 13, a reactor 14 and an atomizer 15; when supplying ammonia to the ammonia reduction denitrification system, urea is continuously added to the molten urea storage tank 12; it can be understood that the urea added to the molten urea storage tank 12 includes but is not limited to granular urea and powdered urea.

[0024] In order to prevent urea from reacting in the molten urea storage tank 12, a heater 13 is disposed in the molten urea storage tank 12 to heat the urea and keep it in a molten state; in this embodiment, the heater 13 can be any one of a steam heat exchanger, an electric heater, a microwave heater, a hybrid heat exchanger, a partition heat exchanger, and a heat storage heat exchanger, or other heating equipment that can maintain the internal temperature of the molten urea storage tank 12 between 135°C and 160°C; As a preferred embodiment of the present application, when the heater 13 is a steam heat exchanger, it can use low-grade steam after temperature and pressure reduction from a coal-fired power plant. This technical solution can improve energy utilization efficiency and reduce energy consumption.

[0025] The reactor 14 is designed to provide an environment for urea reaction; a gas outlet and a solid outlet are provided on the reactor 14; the reactor 14 is connected to the molten urea storage tank 12, and the molten urea output from the molten urea storage tank 12 enters the reactor 14 and reacts in the reactor 14 to generate ammonia gas and cyanuric acid solid particles. The reaction equation of the above reaction is: 3CO(NH2)2→C3N3(OH)3+NH3, wherein ammonia gas leaves the reactor 14 from the gas outlet, and the solid product cyanuric acid gathers at the bottom of the reactor 14 and leaves the reactor 14 through the solid outlet; in the present embodiment, the reactor 14 may adopt a fluidized bed or a tunnel kiln, or other reaction equipment capable of maintaining the internal temperature of the reactor 14 between 200°C and 260°C, and the heating form of the reactor 14 includes but is not limited to electric heating, microwave heating, high-temperature flue gas or hot air indirect heating.

[0026] The atomizer 15 is arranged inside the reactor 14. The molten urea output from the molten urea storage tank 12 is atomized by the atomizer 15 and then enters the reactor 14 in the form of atomized liquid particles. The particle size of the atomized urea is not greater than 200 μm. With this technical solution, the molten urea is atomized into liquid particles and then enters the reactor 14 to react, which can improve the reaction efficiency, make the conversion rate of the molten urea reach more than 99%, and the yield of ammonia reach more than 95%, and can effectively inhibit the occurrence of side reactions. For specific parameters, please refer to the following Table 1 (Urea state and urea conversion rate, ammonia yield analysis data table); Table 1

[0027] In this embodiment, the atomizer 15 may be a rotary atomizer or an ultrasonic atomizer.

[0028] In the above technical solution, the reactor 14 is connected to the molten urea storage tank 12 via a liquid pipeline 16, and a molten urea delivery pump 161 is provided on the liquid pipeline 16. The discharge end of the liquid pipeline 16 is connected to the atomizer 15, so that the molten urea in the molten urea storage tank 12 can be directly pumped into the atomizer 15 for atomization.

[0029] The air inlet of the gas main pipeline 11 is connected to the gas outlet on the reactor 14; as a preferred embodiment of the present application, a separator 17 is provided on the gas main pipeline 11, and the separator 17 is used to capture the solid particles of cyanuric acid carried away from the reactor 14 by the ammonia gas; in the separator 17, the particle separation efficiency is not less than 99%, and the separated solid particles of cyanuric acid are collected together with the solid particles of cyanuric acid at the solid outlet of the reactor 14; the ammonia gas obtained after separation continues to be transported along the gas main pipeline 11 to the rear flow distribution system 2; in this embodiment, the separator 17 can adopt a cyclone separator or a bag dust collector.

[0030] The reaction system 1 of the present application is provided with an atomizer 15 and a separator 17, which can not only ensure the conversion rate of molten urea and the yield of ammonia, but also the high-value by-product cyanuric acid produced by the reaction is beneficial to reducing the cost of ammonia production; in the process of transporting ammonia from the reaction system 1 to the flow distribution system 2, the solid particles of cyanuric acid carried in the ammonia are captured and collected, on the one hand, to effectively ensure the output of cyanuric acid; on the other hand, it can prevent the particles from entering the flow distribution system 2 and causing wear and corrosion to the equipment and pipelines.

[0031] In order to make the flow rate of ammonia gas input into the ammonia reduction denitration system adaptively adjusted according to the flue gas load of the boiler, in this embodiment, the flow distribution system 2 includes: an ammonia gas output subsystem 21 and an ammonia gas storage subsystem 22; Among them, the ammonia output subsystem 21 is used to transport the ammonia output from the reactor 14 to the ammonia reduction denitrification system; more specifically, the ammonia output subsystem 21 includes: a first ammonia branch pipeline 211, a first valve 212 and a first induced draft fan 213; the air inlet of the first ammonia branch pipeline 211 is connected to the gas main pipeline 11, and its air outlet is connected to the ammonia spray grid of the ammonia reduction denitrification system; the first valve 212 and the first induced draft fan 213 are both connected to the first ammonia branch pipeline 211, and the first valve 212 is located at the front end of the air inlet of the first induced draft fan 213; when the ammonia output subsystem 21 is in operation, the first induced draft fan 213 can extract part of the ammonia from the gas main pipeline 11, and transport the ammonia to the ammonia spray grid of the ammonia reduction denitrification system through the first ammonia branch pipeline 211; by adjusting the opening of the first valve 212, the ammonia flow rate entering the ammonia reduction denitrification system from the ammonia output subsystem 21 can be changed.

[0032] The ammonia storage subsystem 22 is used to store the ammonia output from the reaction system 1 when the ammonia production of the reaction system 1 is greater than the ammonia demand of the ammonia reduction denitrification system, so as to reduce the ammonia flow entering the ammonia reduction denitrification system and maintain the internal pressure of the ammonia and cyanuric acid joint detection equipment for denitrification stable; more specifically, the ammonia storage subsystem 22 includes: a second ammonia branch pipeline 221, the air inlet of the second ammonia branch pipeline 221 is connected to the gas main pipeline 11, and the air outlet is connected to the ammonia injection grid of the ammonia reduction denitrification system; the second ammonia branch pipeline 221 is provided with: a second valve 222, The second induced draft fan 223, the cooler 224, the compressor 225, the ammonia storage tank 226, the third valve 227 and the third induced draft fan 228; when the ammonia storage subsystem 22 is in operation, the second induced draft fan 223 can extract part of the ammonia from the gas main pipeline 11, and transport it to the cooler 224 through the second ammonia branch pipeline 221 for cooling; the cooled ammonia is compressed by the compressor 225 and stored in the ammonia storage tank 226 in the form of compressed gas; the third induced draft fan 228 is designed to pump the ammonia stored in the ammonia storage tank 226 to the ammonia injection grid of the ammonia reduction denitrification system.

[0033] In the above technical solution, the amount of ammonia entering the ammonia storage tank 226 can be changed by adjusting the opening of the second valve 222; the flow rate of ammonia output from the ammonia storage tank 226 to the ammonia reduction denitrification system can be changed by adjusting the opening of the third valve 227.

[0034] In this embodiment, the internal pressure of the ammonia storage tank 226 is less than or equal to 0.2 MPa, and its maximum reserve is at least greater than the ammonia required for denitrification of the ammonia reduction denitrification system for 0.5h under the 100% BMCR condition of the boiler unit (i.e., the operating condition under the maximum continuous evaporation rate).

[0035] In this embodiment, the cooler 224 may be a condenser or a water cooler, or other cooling equipment capable of reducing the temperature of the ammonia gas to 20° C. to 40° C.

[0036] As a preferred embodiment of the present application, the molten urea storage tank 12 and the reactor 14 are provided with a thermometer and a press for detecting the temperature and pressure values ​​inside the molten urea storage tank 12 and the reactor 14; the gas main pipeline 11, the first ammonia branch pipeline 211, and the second ammonia branch pipeline 221 are provided with a flow meter and an ammonia concentration meter for detecting the ammonia flow rate and ammonia concentration in each pipeline.

[0037] The flow distribution system 2 of the present application is designed with an ammonia output subsystem 21 and an ammonia storage subsystem 22. When the ammonia production of the reaction system 1 is greater than the ammonia demand of the ammonia reduction denitrification system, the ammonia storage tank 226 can be used to store part of the ammonia in the gas main pipeline 11, thereby reducing the ammonia flow rate input into the ammonia output subsystem 21, and further reducing the ammonia flow rate input into the ammonia reduction denitrification system from the ammonia output subsystem 21; when the ammonia production of the reaction system 1 is less than the ammonia demand of the ammonia reduction denitrification system, the ammonia in the ammonia storage tank 226 and the ammonia in the ammonia output subsystem 21 are jointly input into the ammonia reduction denitrification system, thereby ensuring the ammonia supply capacity of the ammonia and cyanuric acid co-production equipment for denitrification; the technical problem of the difficulty in controlling the ammonia production rate of the equipment in the related technology is solved, and the occurrence of secondary pollution caused by ammonia escape is effectively avoided.

[0038] The present invention also provides a method for controlling a denitrification ammonia and cyanuric acid co-production equipment in this embodiment. The control method adopts the denitrification ammonia and cyanuric acid co-production equipment in Embodiment 1. Specifically, the control method comprises the following steps: S1: Start the heater 13 to heat the molten urea storage tank 12; S2: judging whether the molten urea storage tank 12 meets the molten urea storage conditions based on the internal temperature value of the molten urea storage tank 12 and the first temperature threshold interval; More specifically, step S2 includes: obtaining the internal temperature value of the molten urea storage tank 12, and comparing it with the first temperature threshold interval; if the internal temperature value of the molten urea storage tank 12 does not match the first temperature threshold interval, adjusting the internal temperature value of the molten urea storage tank 12 by the heater 13 until the internal temperature value of the molten urea storage tank 12 is within the first temperature threshold interval, and then entering step S3; In the above steps, before the internal temperature of the molten urea storage tank 12 is heated to the first temperature threshold range, the remaining components of the reaction system 1 except the molten urea storage tank 12 and the heater 13, and the flow distribution system are all in a closed state.

[0039] In the process of heating the molten urea storage tank 12 by the heater 13, the internal temperature value of the molten urea storage tank 12 can be obtained by the thermometer provided on the molten urea storage tank 12, so as to determine whether the internal temperature value of the molten urea storage tank 12 is within the first temperature threshold interval; wherein, the maximum value of the first temperature threshold interval is less than 160°C, and the minimum value thereof is greater than 135°C; if the current internal temperature value of the molten urea storage tank 12 is within the first temperature threshold interval, it indicates that the internal temperature value of the molten urea storage tank 12 matches the first temperature threshold interval, the molten urea storage tank 12 meets the storage conditions of the molten urea, and the molten urea will not react in the molten urea storage tank 12.

[0040] S3: Urea is introduced into the molten urea storage tank 12 and the reactor 14 is started.

[0041] In this step, after the molten urea storage tank 12 meets the storage conditions of molten urea, granular urea or powdered urea is introduced into the molten urea storage tank 12 and collected at the bottom of the molten urea storage tank 12 in a molten state; at the same time, the reactor 14 is started to increase the internal temperature of the reactor 14.

[0042] S4: Based on the internal temperature value of the reactor 14 and the second temperature threshold interval, determining whether the internal environment of the reactor 14 meets the urea thermal decomposition condition; More specifically, step S4 includes: obtaining the internal temperature value of the reactor 14 and comparing it with the second temperature threshold interval; if the internal temperature value of the reactor 14 does not match the second temperature threshold interval, waiting for the reactor 14 to continue heating until the internal temperature value of the reactor 14 is in the second temperature threshold interval, and then entering step S5; In this step, after the reactor 14 is started, while the internal temperature of the reactor 14 is increasing, the internal temperature of the reactor 14 can be obtained by a thermometer provided on the reactor 14, so as to determine whether the internal temperature of the reactor 14 is within the second temperature threshold interval; wherein the maximum value of the second temperature threshold interval is less than 260°C, and the minimum value thereof is greater than 200°C; if the current internal temperature of the reactor 14 is within the second temperature threshold interval, it indicates that the internal temperature of the reactor 14 matches the second temperature threshold interval, the environment within the reactor 14 has met the urea thermal decomposition conditions, and the molten urea can react quickly after being introduced into the reactor 14.

[0043] S5: The molten urea delivery pump 161, the atomizer 15 and the separator 17 are started synchronously, so that the molten urea is atomized into liquid particles, and then enters the reactor 14 to react and generate ammonia and cyanuric acid.

[0044] After the environment in the reactor 14 meets the urea pyrolysis conditions, the molten urea delivery pump 161 pumps the molten urea from the molten urea storage tank 12 to the atomizer 15. The ammonia generated by the pyrolysis of the molten urea passes through the separator 17 to remove solid particles and then enters the rear flow distribution system 2; in this step, the efficiency of the molten urea delivery pump 161 in pumping the molten urea can at least make the ammonia production per unit time of the reactor 14 greater than or equal to the ammonia demand per unit time of the ammonia reduction denitrification system under the 100% BMCR condition of the boiler unit, so as to reduce the probability of a decrease in the denitrification efficiency of the ammonia reduction denitrification system.

[0045] As a preferred embodiment of the present application, in the process of increasing the internal temperature value of the reactor 14, the internal pressure value of the reactor 14 can be obtained by a pressure gauge arranged on the reactor 14, and the internal pressure value of the reactor 14 can be compared with the set pressure threshold interval to determine whether the interior of the reactor 14 is in a slightly negative pressure state; wherein the maximum value of the pressure threshold interval is less than -20Pa, and the minimum value is greater than -100Pa; if the current internal pressure value of the reactor 14 is within the pressure threshold interval, it can prevent the molten urea atomized into liquid particles from being directly brought into the gas main pipeline 11 by the ammonia gas in the reactor 14.

[0046] S6: collecting cyanuric acid solid particles at the solid outlet of the reactor 14 and the separator 17, and controlling the flow distribution system 2 to distribute the flow of ammonia in the gas main pipeline 11, and outputting the distributed ammonia to the ammonia injection grid of the ammonia reduction denitration system; More specifically, in step S6, the flow distribution system 2 is controlled to distribute the flow of ammonia in the gas main pipeline 11, including: judging the denitration state of the ammonia reduction denitration system based on the ammonia production of molten urea pyrolysis in the current reactor 14 and the ammonia required for denitration of the ammonia reduction denitration system under the current working condition of the boiler unit; In this step, the amount of ammonia produced by the thermal decomposition of the molten urea in the current reactor 14 can be calculated and obtained through the indication of the flow meter arranged on the gas main pipeline 11 .

[0047] The ammonia production from the pyrolysis of molten urea in the current reactor 14 is compared with the ammonia demand for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit; if the ammonia production from the pyrolysis of molten urea in the current reactor 14 is greater than the ammonia demand for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit, it is determined that the ammonia reduction denitration system is in an ammonia escape state; at this time, the opening of the first valve 212 is controlled to be reduced, thereby reducing the ammonia flow rate directly input from the ammonia output subsystem 21 to the ammonia reduction denitration system. In the above technical solution, part of the ammonia in the gas main pipeline 11 passes through the ammonia output subsystem 21 is output to the ammonia reduction denitration system; while reducing the opening of the first valve 212, the opening of the second valve 222 is increased, the third valve 227 and the third induced draft fan 228 are closed, and the second induced draft fan 223, the cooler 224, and the compressor 225 are started to store the remaining ammonia in the gas main pipeline 11 in the ammonia storage tank 226, so as to store the excess ammonia generated by the pyrolysis of the reactor 14; it can be understood that the opening of the first valve 212 and the second valve 222 are regulated according to the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit.

[0048] In this step, the ammonia production of the reactor 14 minus the amount of ammonia entering the ammonia storage tank 226 = the ammonia required for denitrification by the ammonia reduction denitrification system; after the pressure of the ammonia storage tank 226 reaches the maximum value, if the ammonia production of the reactor 14 is still greater than the ammonia required for denitrification by the ammonia reduction denitrification system, the molten urea delivery pump 161 is controlled to reduce the efficiency of pumping molten urea to the atomizer 15, thereby reducing the total ammonia production by thermal decomposition of the molten urea in the reactor 14; at this time, the amount of molten urea entering the reactor 14 = the ammonia required for denitrification by the ammonia reduction denitrification system / the ammonia yield of the molten urea in the reactor 14.

[0049] If the ammonia production from the thermal decomposition of molten urea in the current reactor 14 is less than the ammonia demand for denitrification of the ammonia reduction denitrification system under the current operating conditions of the boiler unit, it is determined that the ammonia reduction denitrification system is in a low-efficiency denitrification state; at this time, the second valve 222 is controlled to be closed, and the opening of the first valve 212 is increased, and the ammonia in the gas main pipeline 11 is output to the ammonia reduction denitrification system through the ammonia output subsystem 21; at the same time, the third valve 227 and the third induced draft fan 228 are opened to output the ammonia stored in the ammonia storage tank 226 to the ammonia reduction denitrification system; it can be understood that the opening of the third valve 227 is regulated according to the ammonia demand for denitrification of the ammonia reduction denitrification system under the current operating conditions of the boiler unit.

[0050] In this step, the ammonia production of the reactor 14 + the ammonia output of the ammonia storage tank 226 = the ammonia required for denitrification by the ammonia reduction denitrification system.

[0051] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A denitrification ammonia and cyanuric acid co-production device, wherein the denitrification ammonia and cyanuric acid co-production device is connected to an ammonia reduction denitrification system, It is characterized in that The denitrification ammonia and cyanuric acid co-production equipment comprises: A reaction system, wherein the reaction system is used to pyrolyze urea, output ammonia produced by the reaction, and collect cyanuric acid produced by the reaction; A flow distribution system, wherein the flow distribution system is connected to the reaction system via a gas main pipeline, and the flow distribution system is used to adjust the flow of ammonia gas input into the ammonia reduction denitration system; Wherein, the flow distribution system comprises: an ammonia output subsystem, the ammonia output subsystem being used to transport the ammonia output from the reaction system to an ammonia reduction denitration system; An ammonia storage subsystem is used to store the ammonia in the gas main pipeline when the ammonia production of the reaction system is greater than the ammonia demand of the ammonia reduction denitrification system; and to output the stored ammonia to the ammonia reduction denitrification system when the ammonia production of the reaction system is less than the ammonia demand of the ammonia reduction denitrification system.

2. A denitrification ammonia and cyanuric acid co-production device according to claim 1, It is characterized in that The reaction system comprises: a molten urea storage tank; A heater, wherein the heater is disposed in the molten urea storage tank; A reactor, wherein the reactor is provided with a gas outlet and a solid outlet, the gas outlet is connected to the gas inlet of the gas main pipeline, and the reactor is connected to the molten urea storage tank; A separator is arranged on the gas main pipeline and is used to capture solid particles of cyanuric acid in ammonia.

3. A denitrification ammonia and cyanuric acid co-production device according to claim 2, It is characterized in that The reaction system further comprises: an atomizer, which is arranged inside the reactor and is used to atomize the molten urea outputted from the molten urea storage tank; The reactor is connected to the molten urea storage tank via a liquid pipeline, and the discharge end of the liquid pipeline is connected to the atomizer; a molten urea delivery pump is provided on the liquid pipeline.

4. A denitrification ammonia and cyanuric acid co-production device according to claim 2, It is characterized in that The ammonia output subsystem comprises: a first ammonia branch pipeline, wherein the gas inlet of the first ammonia branch pipeline is connected to the gas main pipeline; a first induced draft fan, the first induced draft fan is connected to the first ammonia branch pipeline, and is used to pump ammonia in the first ammonia branch pipeline into the ammonia reduction denitration system; A first valve is connected to the first ammonia branch pipeline and is located at the front end of the air inlet of the first induced draft fan.

5. The denitrification ammonia and cyanuric acid co-production device according to claim 2, It is characterized in that The ammonia storage subsystem comprises: A second ammonia branch pipeline, wherein the gas inlet of the second ammonia branch pipeline is connected to the gas main pipeline; the second ammonia branch pipeline is provided with: a second induced draft fan, the second induced draft fan being used to extract ammonia gas from the gas main pipeline; a second valve, the second valve being located at a front end of an air inlet of the second induced draft fan; A cooler, located at the rear end of the air outlet of the second induced draft fan, for cooling the ammonia gas output by the second induced draft fan; A compressor, the compressor is connected to the cooler and is used to compress the cooled ammonia; an ammonia storage tank, the ammonia storage tank being connected to the compressor and being used to store compressed ammonia; a third induced draft fan, the third induced draft fan being used to pump ammonia gas in the ammonia storage tank into an ammonia reduction denitration system; A third valve is located at a front end of an air inlet of the third induced draft fan.

6. A method for controlling a denitrification ammonia and cyanuric acid co-production equipment, It is characterized in that The denitrification ammonia and cyanuric acid co-production device according to any one of claims 2 to 5 comprises the following steps: S1: heating molten urea storage tank; S2: judging whether the molten urea storage tank meets the molten urea storage conditions based on the internal temperature value of the molten urea storage tank and the first temperature threshold interval; S3: introducing urea into the molten urea storage tank and heating the reactor; S4: judging whether the environment inside the reactor meets the urea thermal decomposition condition based on the internal temperature value of the reactor and the second temperature threshold interval; S5: atomizing the molten urea into liquid particles, and transporting them into a reactor to react and generate ammonia and cyanuric acid; S6: Collect cyanuric acid solid particles, and control the flow distribution system to distribute the flow of ammonia in the gas main pipeline, and output the distributed ammonia to the ammonia injection grid of the ammonia reduction denitrification system.

7. A method for controlling a denitrification ammonia and cyanuric acid co-production equipment according to claim 6, It is characterized in that Based on the internal temperature value of the molten urea storage tank and the first temperature threshold interval, judging whether the molten urea storage tank meets the molten urea storage condition includes: The internal temperature value of the molten urea storage tank is obtained and compared with the first temperature threshold interval; if the internal temperature value of the molten urea storage tank does not match the first temperature threshold interval, the internal temperature value of the molten urea storage tank is adjusted by the heater until the internal temperature value of the molten urea storage tank is within the first temperature threshold interval, and then step S3 is entered.

8. A method for controlling a denitrification ammonia and cyanuric acid co-production equipment according to claim 6, It is characterized in that Based on the internal temperature value of the reactor and the second temperature threshold interval, judging whether the internal environment of the reactor meets the urea pyrolysis condition includes: The internal temperature value of the reactor is obtained and compared with the second temperature threshold interval; if the internal temperature value of the reactor does not match the second temperature threshold interval, the reactor is kept heated until the internal temperature value of the reactor is in the second temperature threshold interval, and then step S5 is entered.

9. A method for controlling a denitrification ammonia and cyanuric acid co-production equipment according to claim 6, It is characterized in that In step S6, the flow distribution system is controlled to distribute the flow of ammonia gas in the gas main pipeline, including: The denitrification state of the ammonia reduction denitrification system is determined based on the ammonia production from the thermal decomposition of molten urea in the current reactor and the ammonia demand for denitrification of the ammonia reduction denitrification system under the current operating conditions of the boiler unit.

10. A method for controlling a denitrification ammonia and cyanuric acid co-production equipment according to claim 9, It is characterized in that Based on the ammonia production of molten urea pyrolysis in the current reactor and the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit, the denitration state of the ammonia reduction denitration system is judged, including: The ammonia production from the pyrolysis of molten urea in the current reactor is obtained, and compared with the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit; if the ammonia production from the pyrolysis of molten urea in the current reactor is greater than the ammonia required for denitration of the ammonia reduction denitration system under the current operating conditions of the boiler unit, it is determined that the ammonia reduction denitration system is in an ammonia escape state; when the ammonia reduction denitration system is in an ammonia escape state, the ammonia flow rate from the gas main pipeline to the ammonia output subsystem is controlled to be reduced; the ammonia flow rate from the gas main pipeline to the ammonia storage subsystem is increased, and the ammonia entering the ammonia storage subsystem is stored in the ammonia storage subsystem; If the ammonia production from the thermal decomposition of molten urea in the current reactor is less than the ammonia required for denitrification by the ammonia reduction denitrification system under the current operating conditions of the boiler unit, it is judged that the ammonia reduction denitrification system is in a low-efficiency denitrification state; when the ammonia reduction denitrification system is in a low-efficiency denitrification state, the flow distribution system is controlled so that the ammonia in the gas main pipeline is output to the ammonia reduction denitrification system through the ammonia output subsystem; and the ammonia stored in the ammonia storage subsystem is output to the ammonia reduction denitrification system.

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