Tail energy recycling system of waste incineration flue gas purification system and working method

Abstract

The invention relates to the technical field of waste incineration, in particular to a waste incineration flue gas purification system tail energy recycling system and a working method. The system comprises a flue gas cooler system, a circulating water pump, a primary air heater, a secondary air heater, a demineralized water replenishing system, a sampling system, a blowdown system and a dosing system, the flue gas cooler system comprises a flue gas cooler, a plurality of circulating water heat exchange modules are arranged in the flue gas cooler, and the circulating water heat exchange modules are connected in series and / or in parallel; an outlet of the circulating water pump is connected with an inlet of the circulating water heat exchange module, an outlet of the circulating water heat exchange module is connected with circulating water inlets of the primary air heater and the secondary air heater, and a circulating water outlet of the primary air heater and a circulating water outlet of the secondary air heater are connected with an inlet of the circulating water pump through a water return pipeline. And a plurality of branches are arranged on the water return pipeline and are respectively connected with the demineralized water replenishing system, the sampling system, the sewage discharge system and the dosing system.

Description

Technical Field

[0001] The invention relates to the technical field of waste incineration, and in particular to a tail energy recovery and utilization system of a waste incineration flue gas purification system and a working method. Background Art

[0002] Garbage disposal is an important part of urban management. As an effective way to reduce and recycle garbage, garbage incineration has been widely used around the world. Garbage incineration can not only significantly reduce the volume of garbage, but also convert the combustible materials in the garbage into heat energy through the high-temperature combustion process, and then into electrical energy, thus realizing energy recycling. However, the flue gas generated during the garbage incineration process contains a variety of harmful substances, such as particulate matter, acidic gases (such as sulfur dioxide, hydrogen chloride), nitrogen oxides and heavy metals. If these substances are directly discharged into the atmosphere without treatment, they will pose a serious threat to the environment and human health.

[0003] Therefore, the waste incineration flue gas purification system has become an indispensable part of the waste incineration power plant. The waste incineration flue gas purification system is a combination of equipment that integrates multiple purification technologies. It is designed to effectively remove and reduce harmful substances in the flue gas generated during the waste incineration process to ensure that the flue gas emissions meet environmental protection standards, thereby protecting the environment from pollution. The system usually includes multiple links such as dust removal, deacidification, and denitrification to ensure that the flue gas emissions meet environmental protection standards. However, in traditional flue gas purification systems, the flue gas that has been purified through a series of links is often directly discharged into the atmosphere through the chimney, and the large amount of heat energy contained therein is not effectively utilized. This part of heat energy is actually a valuable resource. If it can be recovered and reused, it will be able to significantly improve the overall energy efficiency and economic benefits of the waste incineration power plant.

[0004] The primary air of a waste incinerator refers to the hot air flow sent into the bottom of the furnace, which provides the necessary oxygen for waste combustion and helps combustion, while promoting waste drying and uniform combustion. It is crucial to controlling the combustion process and reducing pollutant emissions.

[0005] The secondary air of a waste incinerator refers to the additional air flow sent into the waste incinerator from the upper middle part of the furnace to supplement the primary air, enhance the disturbance in the furnace, promote the full mixing of waste and oxygen, ensure the full combustion of waste, improve combustion efficiency and reduce pollutant generation.

[0006] The tail flue gas of the traditional waste incineration flue gas purification system is directly discharged into the atmosphere through the chimney, ignoring the large amount of heat energy contained in the flue gas. If this heat energy can be effectively recovered and reused, it will significantly improve the overall efficiency of the waste incineration power plant.

[0007] CN215637204U discloses a waste incineration flue gas waste heat utilization system, which includes a feed hopper, an incinerator, a waste heat boiler, a semi-dry reaction tower, a bag filter, an induced draft fan and a chimney arranged in sequence, and also includes a hot water circulation system. The hot water circulation system is composed of a loop consisting of a secondary low-temperature economizer, a primary low-temperature economizer, a hot water circulation pump and a heater. The waste heat of the flue gas discharged from the waste heat boiler is recovered through two-stage heat exchange, and the recovered heat is used for preheating the primary air, which effectively recovers the waste heat of the high-temperature flue gas and improves the thermal efficiency of the whole plant.

[0008] However, there are still some shortcomings in the prior art, including:

[0009] (1) The heat recovery is limited and the application is single

[0010] Existing technologies mainly limit waste heat recovery to heating primary air. This application method is too single and fails to fully tap the thermal energy potential of flue gas. The flue gas generated during the incineration process contains a large amount of thermal energy, but if it is only recovered by heating the primary air, the heat recovery amount is relatively low, and a large amount of thermal energy is still wasted.

[0011] Failure to consider using waste heat for other valuable process links, such as secondary air preheating, steam generation, plant heating, domestic hot water supply, etc., results in low overall heat recovery efficiency and failure to achieve diversified utilization of heat energy.

[0012] (2) Poor adaptability to operating conditions and insufficient stability

[0013] The existing technology does not fully consider the impact of fluctuations in flue gas temperature, flow rate and other parameters on the waste heat recovery system. During the waste incineration process, these parameters will fluctuate with factors such as waste type, combustion efficiency, seasonal changes, etc., and the existing system lacks effective regulation and control systems to cope with these changes.

[0014] The lack of intelligent control systems to monitor and adjust key parameters such as flue gas temperature and flow in real time makes it difficult for the system to maintain efficient and stable operation under different working conditions. At the same time, there is also a lack of effective monitoring and response measures for changes in flue gas composition, which may lead to system performance degradation or even failure.

[0015] (3) Lack of technical feasibility and completeness

[0016] Existing technologies do not provide a complete heat recovery and utilization solution, and only stay in a single application scenario, resulting in poor feasibility of the technology in practical applications. The lack of detailed system design and equipment selection makes the technology face many difficulties in the process of promotion and application.

[0017] (4) Serious corrosion and blockage problems on the circulating water side and flue gas side

[0018] In the process of heat recovery, the presence of dissolved oxygen in the circulating water will cause corrosion of metal pipes and equipment, resulting in rust particles. These particles will flow with the circulating water and gradually settle in the heat exchanger pipeline, causing pipeline blockage, seriously affecting the heat transfer efficiency and operational stability of the system. The existing technology does not provide effective anti-corrosion and anti-blocking measures, such as the failure to use corrosion-resistant materials, the failure to set up filtering devices or cleaning systems, and the failure to conduct regular water quality monitoring and treatment, which will lead to increasingly serious corrosion and blockage problems.

[0019] Due to the lower temperature on the flue gas side and the high water content in the waste incineration flue gas, acidic low-temperature corrosion is very likely to occur, causing flue gas pipeline leakage, affecting the stable and reliable operation of the entire waste incineration power generation system.

[0020] (5) The circulating water system has a lack of sewage discharge and water replenishment functions

[0021] The existing technology does not consider the sewage system of the circulating water system, which leads to the gradual accumulation of harmful substances (such as salt, impurities, particulate matter, etc.) in the water, affecting the stable operation and heat transfer efficiency of the system. The lack of an effective sewage system and the inability to discharge harmful substances in the water in time may lead to a decline in system performance or even failure.

[0022] At the same time, the prior art does not provide a system water replenishment function. If there is no timely water replenishment function, vaporization and leakage will occur in the circulating water system, affecting the stable operation of the circulating water pump and further affecting the stable operation of the system.

[0023] (6) Inadequate water quality testing and control

[0024] The existing technology does not consider the sampling and dosing system, and the water quality cannot be monitored and controlled in real time. The quality of water directly affects the stable operation and heat transfer efficiency of the system. There is a lack of effective water quality detection methods, and it is impossible to understand the water quality status in time, and it is impossible to effectively control and treat the water quality. There is no sampling point or sampling device, and it is impossible to regularly sample and analyze the circulating water; at the same time, there is no dosing device or dosing system, and it is impossible to add chemicals in time according to the water quality status to adjust and treat the water quality. This may cause the water quality to deteriorate, and then affect the overall performance and stability of the system.

[0025] In summary, the existing heat recovery technology for waste incineration flue gas purification systems has the disadvantages of limited heat recovery and single application, poor adaptability and insufficient stability of operating conditions, lack of technical feasibility and integrity, serious corrosion and blockage problems, lack of sewage discharge and water replenishment functions of the circulating water system, and insufficient water quality detection and control. This field urgently needs to design a new waste incineration flue gas purification system tail energy recovery and utilization system. Summary of the invention

[0026] In view of the problem of heat waste in the waste incineration flue gas purification system, the present invention provides a waste incineration flue gas purification system tail energy recovery and utilization system and working method to maximize the utilization of heat. The system of the present invention has good adaptability to working conditions, has perfect water quality monitoring, sewage discharge, water replenishment and pressure stabilization functions, can effectively prevent blockage, has stable and reliable operation, and the system is complete and has good feasibility.

[0027] In order to solve the above technical problems, this application provides the following technical solutions:

[0028] A tail energy recovery and utilization system for a waste incineration flue gas purification system, comprising a flue gas cooler system, a circulating water pump, a primary air heater, a secondary air heater, a demineralized water replenishment system, a sampling system, a sewage discharge system, and a dosing system;

[0029] The flue gas cooler system comprises a flue gas cooler, wherein a plurality of circulating water heat exchange modules are arranged in the flue gas cooler, and the circulating water heat exchange modules are connected in series and / or in parallel; the outlet of the circulating water pump is connected to the inlet of the circulating water heat exchange module, and the outlet of the circulating water heat exchange module is respectively connected to the circulating water inlet of the primary air heater and the secondary air heater, and the circulating water outlet of the primary air heater and the circulating water outlet of the secondary air heater are connected to the inlet of the circulating water pump through a return water pipeline;

[0030] The return water pipeline is provided with a plurality of branches, and the branches are respectively connected with the demineralized water replenishment system, the sampling system, the sewage discharge system and the dosing system.

[0031] Further, the circulating water pump comprises a first circulating water pump and a second circulating water pump arranged in parallel, the outlet of the first circulating water pump is provided with a first electric valve, and the outlet of the second circulating water pump is provided with a second electric valve;

[0032] The outlet of the first electric valve and the outlet of the second electric valve are connected to a water outlet pipeline, and a flow meter and a first water temperature measuring point are sequentially arranged at the front end of the water outlet pipeline.

[0033] Furthermore, the number of the circulating water heat exchange modules is two, namely a first circulating water heat exchange module and a second circulating water heat exchange module;

[0034] The inlet and outlet of the first circulating water heat exchange module are both connected to the water outlet pipeline, a first valve and a second water temperature measuring point are sequentially arranged on the first branch between the water outlet pipeline and the inlet of the first circulating water heat exchange module, a third water temperature measuring point is arranged on the second branch between the outlet of the first circulating water heat exchange module and the water outlet pipeline; a second valve is arranged on the water outlet pipeline between the first branch and the second branch;

[0035] The inlet and outlet of the second circulating water heat exchange module are both connected to the water outlet pipeline, a third valve and a fourth water temperature measuring point are sequentially arranged on the third branch between the water outlet pipeline and the inlet of the second circulating water heat exchange module, a fifth water temperature measuring point is arranged on the fourth branch between the outlet of the second circulating water heat exchange module and the water outlet pipeline; a fourth valve is arranged on the water outlet pipeline between the third branch and the fourth branch;

[0036] A sixth water temperature measuring point is provided on the water outlet pipeline behind the connection point between the fourth branch and the water outlet pipeline.

[0037] Furthermore, the circulating water inlet pipeline of the primary air heater is provided with a third electric valve, and the circulating water outlet pipeline of the primary air heater is provided with a primary air heater outlet water temperature measuring point and a first filter in sequence;

[0038] The air inlet of the primary air heater is connected to the primary fan outlet, and a primary air heater inlet temperature measuring point is provided on the pipeline between the two; the air outlet of the primary air heater is connected to the primary air preheater inlet, and a primary air heater outlet temperature measuring point is provided on the pipeline between the two.

[0039] Furthermore, a fourth electric valve is provided at the front end of the circulating water inlet of the secondary air heater, and a secondary air heater outlet water temperature measuring point and a second filter are provided in sequence on the circulating water outlet pipeline of the secondary air heater.

[0040] The air inlet of the secondary air heater is connected to the secondary air fan outlet, and a secondary air heater inlet temperature measuring point is provided on the pipeline between the two; the air outlet of the secondary air heater is connected to the secondary air air preheater inlet, and a secondary air heater outlet temperature measuring point is provided on the pipeline between the two.

[0041] Furthermore, a pressure measuring point is provided on the return water pipeline behind the connection point between the desalted water replenishment system and the return water pipeline.

[0042] Furthermore, a fifth electric valve is provided on the pipeline between the sewage system and the return water pipeline.

[0043] Furthermore, a smoke inlet temperature measuring point is provided on the smoke inlet pipeline of the smoke cooler, and a smoke outlet temperature measuring point is provided on the smoke outlet pipeline of the smoke cooler.

[0044] Furthermore, the shell of the flue gas cooler and the low-temperature zone after cooling are the anti-corrosion areas, and the anti-corrosion areas are subjected to two-cloth and six-coat anti-corrosion, specifically, rolling on the first coat of composite resin coating → rolling on the second coat of composite resin coating and pasting a layer of glass fiber cloth → rolling on the third coat of composite resin coating and pasting a layer of glass fiber cloth → rolling on the third coat of composite resin coating.

[0045] The working method of the tail energy recovery and utilization system of the waste incineration flue gas purification system comprises the following steps:

[0046] (1) The flow rate of each circulating water heat exchange module is controlled by valves. When the temperature of the sixth water temperature measuring point is higher than 120°C, the number of circulating water heat exchange modules put into use is reduced, the heat exchange area is reduced, and the heat exchange amount is reduced to ensure that the sixth water temperature measuring point is lower than 120°C;

[0047] (2) Ensure that the temperature detected at the flue gas inlet temperature measuring point is between 140 and 150°C; when the temperature at the flue gas inlet temperature measuring point rises, increase the flow rate of the first circulating water pump or the second circulating water pump accordingly to increase the system circulating water volume; under normal circumstances, the first circulating water pump runs and the second circulating water pump stops; when the first circulating water pump fails, open the second electric valve, close the first electric valve, and start the second circulating water pump;

[0048] (3) Controlling the circulating water flow of the primary air heater and the secondary air heater through the third electric valve and the fourth electric valve;

[0049] The primary air heater inlet temperature measuring point and the primary air heater outlet temperature measuring point are used for temperature detection and do not participate in control; the secondary air heater inlet temperature measuring point and the secondary air heater outlet temperature measuring point are used for temperature detection and do not participate in control;

[0050] The sixth water temperature measuring point is used to display the heater inlet water temperature and does not participate in the control; the primary air heater outlet water temperature measuring point and the secondary air heater outlet water temperature measuring point are used to display the heater outlet water temperature and do not participate in the control;

[0051] (4) Monitor the pressure at the pressure measuring point and replenish the pipeline with water through the desalted water replenishment system to ensure that the pressure is 0.3-0.5 MPa. Start replenishment when the pressure is lower than 0.3 MPa and stop replenishment when the pressure reaches 0.5 MPa;

[0052] (5) The circulating water is sampled through the sampling system to detect the conductivity, dissolved oxygen and pH value; the pH value of the system is maintained at 9-12. When it is lower than the set value, NaOH solution is automatically added to the system through the metering pump; the conductivity of the system should be lower than 1500us / cm. If it is higher than this value, an alarm will be triggered and the fifth electric valve will be opened for sewage discharge; the dissolved oxygen range of the system is 0-2mg / L. When it exceeds 0.7mg / L, the dosing system will be started to add sodium sulfite, and it will be stopped when it is lower than 0.4mg / L.

[0053] (6) Filter and remove system impurities through the first filter and the second filter, and clean or replace them regularly.

[0054] The present invention collects and utilizes the heat energy at the tail of the flue gas purification system after the garbage incineration through the innovatively designed tail energy recovery and utilization system of the garbage incineration flue gas purification system to preheat or heat the air supply required for garbage incineration, including the crucial primary air and secondary air. This improvement not only reduces the amount of steam consumed for air supply heating and reduces operating costs, but also allows the heat energy that was originally wasted to be converted into useful energy. The saved steam can be further used for external heating or input into a steam turbine for power generation, thereby greatly improving the power output and economic benefits of the power plant without affecting the garbage treatment efficiency.

[0055] Compared with the prior art, the waste incineration flue gas purification system tail energy recovery and utilization system and working method of the present invention have at least the following beneficial effects:

[0056] (1) Increased heat recovery and diversified applications

[0057] The system of the present invention not only uses the heat in the flue gas to heat the primary air, but also heats the secondary air through the secondary air heater, thus realizing diversified utilization of heat. This design significantly increases the amount of heat recovery, making fuller use of the heat energy in the flue gas, thereby improving the overall heat recovery efficiency.

[0058] (2) Strong adaptability and high stability in operating conditions

[0059] Through the modular flue gas cooler design, the system of the present invention can flexibly adjust the heat exchange area and heat exchange capacity to adapt to the fluctuations of flue gas temperature, flow rate and other parameters. The introduction of the automatic control system enables the entire heat exchange system to be automatically adjusted according to actual needs, ensuring the stable operation of the system under different working conditions. The implementation of the temperature and flow control strategy further improves the stability and reliability of the system.

[0060] (3) High technical feasibility and integrity

[0061] The system of the present invention provides a complete heat recovery and utilization solution, including multiple components such as flue gas cooler, primary air heater, secondary air heater, as well as auxiliary systems such as circulating water pump, sampling monitoring system, sewage discharge system, dosing system, water replenishment and pressure stabilization system, etc. This systematic design greatly enhances the feasibility of the technology in practical applications and also improves the integrity of the technology.

[0062] (4) Effectively prevent water side corrosion and blockage

[0063] By setting up the first filter and the second filter, impurities in the circulating water can be removed, thereby reducing the risk of corrosion and blockage. A water quality management and maintenance system has been established, including a sampling monitoring system, a dosing system, and a sewage system, which can monitor and control the water quality of the circulating water in real time, further preventing the occurrence of corrosion and blockage.

[0064] (5) Effectively prevent flue gas side corrosion

[0065] The use of low-cost glass cloth and composite resin can effectively prevent corrosion; the cost is lower than high-cost anti-corrosion solutions such as 2205, 2507, and titanium steel composite plates.

[0066] (6) Improved sewage discharge and water replenishment functions of the circulating water system

[0067] The system of the present invention is provided with a sewage discharge system, which can discharge harmful substances in the circulating water in time, ensuring the stable operation and heat transfer efficiency of the system. The introduction of the water replenishment and pressure stabilization system ensures the stability of the system pressure and avoids the problem of unstable operation of the circulating water pump caused by vaporization, leakage and other reasons.

[0068] (7) Accurate water quality testing and control

[0069] The setting of the sampling monitoring system enables the system of the present invention to monitor the water quality indicators of the circulating water in real time, providing data support for water quality control. The introduction of the dosing system can timely add chemicals to adjust and treat the water quality according to the water quality conditions, ensuring that the water quality of the circulating water meets the system requirements.

[0070] (8) High level of intelligence and automation

[0071] The entire heat exchange system is automatically controlled through pipelines, valves and control systems, which improves the intelligence and automation level of the system. This design not only reduces manual intervention, but also improves the response speed and adjustment accuracy of the system.

[0072] (9) The present invention solves the technical problems of low energy utilization efficiency and high operating costs in waste incineration power plants by efficiently recovering and reusing flue gas heat, thereby promoting sustainable utilization of energy and green development of the environment.

[0073] The tail energy recovery and utilization system and working method of the waste incineration flue gas purification system of the present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a structural schematic diagram of the tail energy recovery and utilization system of the waste incineration flue gas purification system of the present invention.

[0075] Among them, 1- flue gas cooler, 2- first circulating water pump, 3- second circulating water pump, 4- primary air heater, 5- secondary air heater, 6- demineralized water replenishment system, 7- sampling system, 8- sewage system, 9- dosing system,;

[0076] 11-anti-corrosion area; 12-smoke inlet temperature measuring point, 13-smoke outlet temperature measuring point, 14-first valve, 15-second valve, 16-third valve, 17-fourth valve;

[0077] 21-first electric valve, 22-flow meter, 23-first water temperature measuring point, 24-second water temperature measuring point, 25-third water temperature measuring point, 26-fourth water temperature measuring point, 27-fifth water temperature measuring point, 28-sixth water temperature measuring point;

[0078] 31- second electric valve;

[0079] 41-third electric valve, 42-first filter, 43-primary fan outlet, 44-primary air preheater inlet, 45-primary air heater inlet temperature measuring point, 46-primary air heater outlet temperature measuring point, 47-primary air heater outlet water temperature measuring point;

[0080] 51- the fourth electric valve, 52- the second filter, 53- the secondary fan outlet, 54- the secondary air preheater inlet, 55- the secondary air heater inlet temperature measuring point, 56- the secondary air heater outlet temperature measuring point, 57- the secondary air heater outlet water temperature measuring point;

[0081] 61-pressure measuring point; 81-fifth electric valve. DETAILED DESCRIPTION

[0082] like Figure 1 As shown, a tail energy recovery and utilization system of a waste incineration flue gas purification system includes a flue gas cooler system, a circulating water pump, a primary air heater 4, a secondary air heater 5, a desalted water replenishing system 6, a sampling system 7, a sewage discharge system 8, and a dosing system 9; the flue gas cooler system includes a flue gas cooler 1, and the flue gas cooler 1 is provided with two circulating water heat exchange modules, the outlet of the circulating water pump is connected to the inlet of the circulating water heat exchange module, and the outlet of the circulating water heat exchange module is respectively connected to the circulating water inlet of the primary air heater 4 and the secondary air heater 5, and the circulating water outlet of the primary air heater 4 and the circulating water outlet of the secondary air heater 5 are connected to the inlet of the circulating water pump through a return water pipeline; a plurality of branches are arranged on the return water pipeline, and the branches are respectively connected to the desalted water replenishing system 6, the sampling system 7, the sewage discharge system 8 and the dosing system 9.

[0083] A flue gas inlet temperature measuring point 12 is provided on the flue gas inlet pipeline of the flue gas cooler 1 , and a flue gas outlet temperature measuring point 13 is provided on the flue gas outlet pipeline of the flue gas cooler 1 .

[0084] The shell of the flue gas cooler 1 and the low temperature area after cooling are the anti-corrosion area 11, and the anti-corrosion area 11 is subjected to two-cloth six-coat anti-corrosion, specifically rolling the first layer of composite resin coating → rolling the second layer of composite resin coating and pasting a layer of glass cloth → rolling the third layer of composite resin coating and pasting a layer of glass cloth → rolling the third layer of composite resin coating, with good anti-corrosion effect and low cost. Among them, the composite resin coating can be selected from the OM5 composite resin coating of Taiyuan Aoem Chimney Material Co., Ltd.; the glass cloth can be selected from the glass cloth of Lingqiu Glass Fiber Factory in Shanxi Province, with a specification of CN10×10×0.1mm.

[0085] The circulating water pump includes a first circulating water pump 2 and a second circulating water pump 3 arranged in parallel, the outlet of the first circulating water pump 2 is provided with a first electric valve 21, and the outlet of the second circulating water pump 3 is provided with a second electric valve 31; the outlet of the first electric valve 21 and the outlet of the second electric valve 31 are connected to a water outlet pipeline, and a flow meter 22 and a first water temperature measuring point 23 are provided at the front end of the water outlet pipeline in sequence.

[0086] The two circulating water heat exchange modules are respectively a first circulating water heat exchange module and a second circulating water heat exchange module; the inlet and outlet of the first circulating water heat exchange module are both connected to the outlet water pipeline, and a first valve 14 and a second water temperature measuring point 24 are sequentially arranged on the first branch between the outlet water pipeline and the inlet of the first circulating water heat exchange module, and a third water temperature measuring point 25 is arranged on the second branch between the outlet of the first circulating water heat exchange module and the outlet water pipeline; a second valve 15 is arranged on the outlet water pipeline between the first branch and the second branch; the inlet and outlet of the second circulating water heat exchange module are both connected to the outlet water pipeline, and a third valve 16 and a fourth water temperature measuring point 26 are sequentially arranged on the third branch between the outlet water pipeline and the inlet of the second circulating water heat exchange module, and a fifth water temperature measuring point 27 is arranged on the fourth branch between the outlet of the second circulating water heat exchange module and the outlet water pipeline; a fourth valve 17 is arranged on the outlet water pipeline between the third branch and the fourth branch.

[0087] A sixth water temperature measuring point 28 is provided on the water outlet pipeline behind the connection point between the fourth branch and the water outlet pipeline.

[0088] The circulating water inlet pipeline of the primary air heater 4 is provided with a third electric valve 41, and the circulating water outlet pipeline of the primary air heater 4 is provided with a primary air heater outlet water temperature measuring point 47 and a first filter 42 in sequence; the air inlet of the primary air heater 4 is connected to the primary fan outlet 43, and a primary air heater inlet temperature measuring point 45 is provided on the pipeline between the two; the air outlet of the primary air heater 4 is connected to the primary air air preheater inlet 44, and a primary air heater outlet temperature measuring point 46 is provided on the pipeline between the two.

[0089] A fourth electric valve 51 is provided at the front end of the circulating water inlet of the secondary air heater 5, and a secondary air heater outlet water temperature measuring point 57 and a second filter 52 are provided in sequence on the circulating water outlet pipeline of the secondary air heater 5. The air inlet of the secondary air heater 5 is connected to the secondary fan outlet 53, and a secondary air heater inlet temperature measuring point 55 is provided on the pipeline between the two; the air outlet of the secondary air heater 5 is connected to the secondary air preheater inlet 54, and a secondary air heater outlet temperature measuring point 56 is provided on the pipeline between the two.

[0090] A pressure measuring point 61 is provided on the return water pipeline behind the connection point between the desalted water replenishment system 6 and the return water pipeline. A fifth electric valve 81 is provided on the pipeline between the sewage system 8 and the return water pipeline.

[0091] The entire heat exchange system is automatically controlled through pipelines, valves, and control systems. The circulating water passes through the first circulating water pump 2 (or the second circulating water pump 3), the first electric regulating valve 21 (or the second electric valve 31), the flow meter 22, the first water temperature measuring point 23, the circulating water heat exchange module, the sixth water temperature measuring point 28, the primary air heater 4 and the secondary air heater 5, the sampling system 7, the sewage system 8, the dosing system 9, the demineralized water replenishment system 6, and finally reaches the first circulating water pump 2 (or the second circulating water pump 3) to complete the closed cycle.

[0092] The working method of the tail energy recovery and utilization system of the waste incineration flue gas purification system comprises the following steps:

[0093] (1) The flow rate of the two circulating water heat exchange modules is controlled by valves (for example, when the second valve 15 and the fourth valve 17 are closed, and the first valve 14 and the third valve 16 are opened, the circulating water flows through the two modules; when the first valve 14 and the fourth valve 17 are closed, and the second valve 15 and the third valve 16 are opened, the circulating water flows through the second circulating water heat exchange module. Similarly, other operation modes can be derived). When the temperature of the sixth water temperature measuring point is higher than 120°C, the number of circulating water heat exchange modules put into use is reduced, the heat exchange area is reduced, and the heat exchange amount is reduced to ensure that the sixth water temperature measuring point is lower than 120°C.

[0094] (2) Ensure that the temperature detected at the flue gas inlet temperature measuring point is between 140 and 150°C; when the temperature at the flue gas inlet temperature measuring point rises, increase the flow rate of the first circulating water pump 2 or the second circulating water pump 3 accordingly to increase the system circulating water volume; under normal circumstances, the first circulating water pump 2 runs and the second circulating water pump 3 stops; when the first circulating water pump 2 fails, open the second electric valve 31, close the first electric valve 21, and start the second circulating water pump 3 to ensure reliable operation of the system.

[0095] (3) Controlling the circulating water flow of the primary air heater 4 and the secondary air heater 5 by means of the third electric valve 41 and the fourth electric valve 51;

[0096] The primary air heater inlet temperature measuring point 45 and the primary air heater outlet temperature measuring point 46 are used for temperature detection and do not participate in control; the secondary air heater inlet temperature measuring point 55 and the secondary air heater outlet temperature measuring point 56 are used for temperature detection and do not participate in control;

[0097] The sixth water temperature measuring point 28 is used to display the heater inlet water temperature and does not participate in the control; the primary air heater outlet water temperature measuring point 47 and the secondary air heater outlet water temperature measuring point 57 are used to display the heater outlet water temperature and do not participate in the control.

[0098] (4) Monitor the pressure at the pressure measuring point 61 and automatically replenish the pipeline with water through the desalted water replenishment system 6 to ensure that the pressure is 0.3-0.5 MPa. Start replenishment when the pressure is lower than 0.3 MPa and stop replenishment when the pressure reaches 0.5 MPa, thereby improving the safety and stability of the system.

[0099] (5) The circulating water is sampled through the sampling system 7 to detect parameters such as conductivity, dissolved oxygen, and pH value; the pH value of the system is maintained at 9-12, and when it is lower than the set value, NaOH solution is automatically added to the system through the metering pump; the conductivity of the system should be lower than 1500us / cm, and if it is higher than this value, an alarm is triggered and the fifth electric valve 81 is opened for sewage discharge; the dissolved oxygen range of the system is 0-2mg / L, and when it exceeds 0.7mg / L, the dosing system 9 is started to add sodium sulfite, and when it is lower than 0.4mg / L, it is stopped. The water quality indicators of the circulating water are monitored in real time, and the dosing and sewage discharge operations are automatically performed as needed to ensure that the water quality of the circulating water meets the system requirements.

[0100] (6) The system impurities are filtered out through the first filter 42 and the second filter 52, and are cleaned or replaced regularly.

[0101] The present invention forms a flue gas recovery and utilization system with complete functions and reliable operation through a flue gas cooler, a primary air heater, a secondary air heater, a circulating water pump, a sampling system, a sewage discharge system, a dosing system, and a demineralized water replenishment system. The heat in the flue gas is recovered and used to heat the primary air and the secondary air respectively through the primary air heater and the secondary air heater.

[0102] This system uses a flue gas cooler composed of several heat exchange modules. The modules are flexibly controlled through pipes and valves. The heat exchange area and heat exchange amount can be adjusted according to actual needs to improve system efficiency and flexibility.

[0103] The entire heat exchange system, including flue gas cooler, circulating water pump, primary air heater, secondary air heater, etc., is automatically controlled through pipelines, valves and control systems, which improves the stability and reliability of the system. In addition, by setting multiple temperature measurement points and valves, the circulating water temperature, flow rate and the number of flue gas cooler modules can be accurately controlled to ensure that the system can operate stably under different working conditions.

[0104] In summary, the system achieves the advantages of increased heat recovery and diversified applications, strong adaptability and high stability of operating conditions, high technical feasibility and integrity, effective prevention of corrosion and blockage, perfect sewage discharge and water replenishment functions of the circulating water system, and precise water quality detection and control. These advantages make the present invention have significant advantages and broad application prospects in the field of heat recovery and utilization at the tail of garbage incineration flue gas purification system.

[0105] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A waste incineration flue gas purification system tail energy recovery and utilization system, characterized by: It includes a flue gas cooler system, a circulating water pump, a primary air heater (4), a secondary air heater (5), a desalted water replenishment system (6), a sampling system (7), a sewage discharge system (8), and a dosing system (9); The flue gas cooler system comprises a flue gas cooler (1), wherein the flue gas cooler (1) is provided with a plurality of circulating water heat exchange modules, wherein the circulating water heat exchange modules are connected in series and / or in parallel; the outlet of the circulating water pump is connected to the inlet of the circulating water heat exchange module, and the outlet of the circulating water heat exchange module is respectively connected to the circulating water inlet of the primary air heater (4) and the secondary air heater (5); the circulating water outlet of the primary air heater (4) and the circulating water outlet of the secondary air heater (5) are connected to the inlet of the circulating water pump via a return water pipeline; The return water pipeline is provided with a plurality of branches, which are respectively connected to the demineralized water replenishment system (6), the sampling system (7), the sewage discharge system (8) and the drug addition system (9).

2. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: The circulating water pump comprises a first circulating water pump (2) and a second circulating water pump (3) which are arranged in parallel, the outlet of the first circulating water pump (2) is provided with a first electric valve (21), and the outlet of the second circulating water pump (3) is provided with a second electric valve (31); The outlet of the first electric valve (21) and the outlet of the second electric valve (31) are connected to a water outlet pipeline, and a flow meter (22) and a first water temperature measuring point (23) are provided at the front end of the water outlet pipeline in sequence.

3. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: The number of the circulating water heat exchange modules is two, namely a first circulating water heat exchange module and a second circulating water heat exchange module; The inlet and outlet of the first circulating water heat exchange module are both connected to the water outlet pipeline, a first valve (14) and a second water temperature measuring point (24) are provided in sequence on a first branch between the water outlet pipeline and the inlet of the first circulating water heat exchange module, a third water temperature measuring point (25) is provided on a second branch between the outlet of the first circulating water heat exchange module and the water outlet pipeline; a second valve (15) is provided on the water outlet pipeline between the first branch and the second branch; The inlet and outlet of the second circulating water heat exchange module are both connected to the water outlet pipeline, a third valve (16) and a fourth water temperature measuring point (26) are provided in sequence on the third branch between the water outlet pipeline and the inlet of the second circulating water heat exchange module, a fifth water temperature measuring point (27) is provided on the fourth branch between the outlet of the second circulating water heat exchange module and the water outlet pipeline; a fourth valve (17) is provided on the water outlet pipeline between the third branch and the fourth branch; A sixth water temperature measuring point (28) is provided on the water outlet pipeline behind the connection point between the fourth branch and the water outlet pipeline.

4. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: The circulating water inlet pipeline of the primary air heater (4) is provided with a third electric valve (41), and the circulating water outlet pipeline of the primary air heater (4) is provided with a primary air heater outlet water temperature measuring point (47) and a first filter (42) in sequence; The air inlet of the primary air heater (4) is connected to the primary air fan outlet (43), and a primary air heater inlet temperature measuring point (45) is provided on the pipeline between the two; the air outlet of the primary air heater (4) is connected to the primary air preheater inlet (44), and a primary air heater outlet temperature measuring point (46) is provided on the pipeline between the two.

5. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: A fourth electric valve (51) is provided at the front end of the circulating water inlet of the secondary air heater (5), and a secondary air heater outlet water temperature measuring point (57) and a second filter (52) are provided in sequence on the circulating water outlet pipeline of the secondary air heater (5); The air inlet of the secondary air heater (5) is connected to the secondary air fan outlet (53), and a secondary air heater inlet temperature measuring point (55) is provided on the pipeline between the two; the air outlet of the secondary air heater (5) is connected to the secondary air preheater inlet (54), and a secondary air heater outlet temperature measuring point (56) is provided on the pipeline between the two.

6. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: A pressure measuring point (61) is provided on the return water pipeline behind the connection point between the desalted water replenishment system (6) and the return water pipeline.

7. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: A fifth electric valve (81) is provided on the pipeline between the sewage discharge system (8) and the return water pipeline.

8. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: A smoke inlet temperature measuring point (12) is provided on the smoke inlet pipeline of the smoke cooler (1), and a smoke outlet temperature measuring point (13) is provided on the smoke outlet pipeline of the smoke cooler (1).

9. The tail energy recovery and utilization system of the waste incineration flue gas purification system according to claim 1 is characterized by: The shell of the flue gas cooler (1) and the low-temperature zone after cooling are the anti-corrosion area (11), and the anti-corrosion area (11) is subjected to two-cloth six-coat anti-corrosion, specifically rolling on a first coat of composite resin coating → rolling on a second coat of composite resin coating and pasting a layer of glass fiber cloth → rolling on a third coat of composite resin coating and pasting a layer of glass fiber cloth → rolling on three coats of composite resin coating.

10. The working method of the tail energy recovery and utilization system of the waste incineration flue gas purification system according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) The flow rate of each circulating water heat exchange module is controlled by valves. When the temperature of the sixth water temperature measuring point is higher than 120°C, the number of circulating water heat exchange modules put into use is reduced, the heat exchange area is reduced, and the heat exchange amount is reduced to ensure that the sixth water temperature measuring point is lower than 120°C; (2) Ensure that the temperature detected at the flue gas inlet temperature measuring point is between 140 and 150°C; when the temperature at the flue gas inlet temperature measuring point rises, increase the flow rate of the first circulating water pump or the second circulating water pump accordingly to increase the system circulating water volume; under normal circumstances, the first circulating water pump runs and the second circulating water pump stops; when the first circulating water pump fails, open the second electric valve, close the first electric valve, and start the second circulating water pump; (3) Controlling the circulating water flow of the primary air heater and the secondary air heater through the third electric valve and the fourth electric valve; The primary air heater inlet temperature measuring point and the primary air heater outlet temperature measuring point are used for temperature detection and do not participate in control; the secondary air heater inlet temperature measuring point and the secondary air heater outlet temperature measuring point are used for temperature detection and do not participate in control; The sixth water temperature measuring point is used to display the heater inlet water temperature and does not participate in the control; the primary air heater outlet water temperature measuring point and the secondary air heater outlet water temperature measuring point are used to display the heater outlet water temperature and do not participate in the control; (4) Monitor the pressure at the pressure measuring point and replenish the pipeline with water through the desalted water replenishment system to ensure that the pressure is 0.3-0.5 MPa. Start replenishment when the pressure is lower than 0.3 MPa and stop replenishment when the pressure reaches 0.5 MPa; (5) The circulating water is sampled through the sampling system to detect the conductivity, dissolved oxygen and pH value; the pH value of the system is maintained at 9-12. When it is lower than the set value, NaOH solution is automatically added to the system through the metering pump; the conductivity of the system should be lower than 1500us / cm. If it is higher than this value, an alarm will be triggered and the fifth electric valve will be opened for sewage discharge; the dissolved oxygen range of the system is 0-2mg / L. When it exceeds 0.7mg / L, the dosing system will be started to add sodium sulfite, and it will be stopped when it is lower than 0.4mg / L. (6) Filter and remove system impurities through the first filter and the second filter, and clean or replace them regularly.

Images