A flue gas waste heat deep recovery system

Abstract

The present application relates to a flue gas waste heat deep recovery system, comprising: a shell, a flue gas channel is arranged inside the shell, and a spray assembly for spraying and cooling the flue gas is installed in the flue gas channel; a water tank for receiving spray water is arranged at the bottom of the shell, and the water tank is connected to a circulating heat exchange assembly through a pipeline. The spray assembly for directly spraying and cooling the flue gas constitutes a primary heat exchange of the flue gas, and the heat in the flue gas can be recovered into the spray water. The heat transfer efficiency is effectively improved through the form of direct gas-liquid contact, and the heat in the flue gas can be released more fully. The spray water after the flue gas is sprayed and cooled is stored in the water tank, realizing the heat storage function. The circulating heat exchange assembly connected to the water tank can form a secondary heat exchange, so that the heat storage energy of the spray water is transferred to the outside in the form of circulating heat exchange, which effectively reduces the temperature of the spray water after the heat is transferred, which is conducive to the direct recovery of the flue gas heat and ensures the recovery effect of the flue gas waste heat.

Description

Technical Field

[0001] The present application relates to the technical field of waste heat recovery, and in particular to a flue gas waste heat deep recovery system. Background Art

[0002] The heat loss of coal-fired and gas-fired boilers mainly includes heat loss from flue gas, heat loss from sewage, heat loss from incomplete combustion, and heat dissipation. The heat loss from flue gas and sewage has a greater impact on the thermal efficiency of the boiler and is easy to recycle. At present, the exhaust temperature of gas boilers is generally around 200°C, and the heat loss from flue gas is more than 10%; when the exhaust temperature is high, water vapor cannot condense to release latent heat energy, and is discharged with the flue gas, wasting heat energy. It also carries a large amount of sensible heat energy, which is also discharged with the flue gas, the so-called "white smoke" phenomenon.

[0003] There are many flue gas waste heat recovery devices in the prior art, but they all use non-direct contact heat conduction systems for heat exchange, and the heat exchange effect is low; the flue gas waste heat recovery device generally only includes a circulating heat exchange system, and the heat utilization rate is not high.

[0004] In addition, the flue gas waste heat recovery technology of most gas-fired boilers and coal-fired boilers currently has a high cold source temperature, which is unable to deeply cool the flue gas, and the problem of heat exchanger corrosion is serious. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a flue gas waste heat deep recovery system, which realizes the automatic waste heat recovery function and greatly improves the heat recovery efficiency in the flue gas.

[0006] The present invention provides a flue gas waste heat deep recovery system, comprising: a shell,

[0007] A smoke channel is arranged inside the shell, and a spray component for spraying and cooling the smoke is installed in the smoke channel;

[0008] A water tank for receiving spray water is arranged at the bottom of the shell, and the water tank is connected to a circulating heat exchange component through a pipeline.

[0009] In a further embodiment, the spray assembly includes a high-temperature section spray assembly and a low-temperature section spray assembly, and a flue gas deflector is provided between the high-temperature section spray assembly and the low-temperature section spray assembly.

[0010] In a further embodiment, a smoke inlet is provided on the side of the shell, a smoke outlet is provided on the top of the shell, the high-temperature section spray assembly is provided on the inner side of the smoke inlet, and the low-temperature section spray assembly is provided at the bottom of the smoke outlet.

[0011] In a further embodiment, a gas-liquid mixing assembly is further arranged between the high-temperature section spray assembly and the low-temperature section spray assembly, and the gas-liquid mixing assembly includes a bubble nozzle and a gas-liquid mixing sieve plate, the bubble nozzle is installed on the side wall of the shell, and the gas-liquid mixing sieve plate is located below the bubble nozzle and arranged in the flue gas channel.

[0012] In a further embodiment, the smoke deflector includes two smoke deflectors that are staggered at intervals, each of which is inclined relative to a horizontal plane, one of which is connected to the bottom of the gas-liquid mixing sieve plate, and the other smoke deflector is connected to the water tank.

[0013] In a further embodiment, the water tank includes a high-temperature water tank and a low-temperature water tank for receiving spray water from the high-temperature section spray assembly and the low-temperature section spray assembly, and the circulating heat exchange assembly includes a circulating pump and a heat exchanger respectively arranged corresponding to the high-temperature water tank and the low-temperature water tank.

[0014] In a further embodiment, a spray pipe is connected between the heat exchanger and the shell, and the spray assembly includes a spray branch pipe connected to the spray pipe and a nozzle installed on the spray branch pipe, and the spray branch pipe is detachably connected to the spray pipe via a flange.

[0015] In a further embodiment, a gas-liquid mixing branch is connected to the spray pipe, the bubble nozzle is connected to the gas-liquid mixing branch, a plurality of through holes are evenly distributed on the gas-liquid mixing sieve plate, and the bubble nozzle includes a butterfly nozzle arranged below the low-temperature section spray assembly.

[0016] In a further embodiment, the heat exchanger includes a high-temperature section heat exchanger and a low-temperature section heat exchanger, and the spray pipe includes a high-temperature section spray pipe and a low-temperature section spray pipe respectively connected to the high-temperature section heat exchanger and the low-temperature section heat exchanger;

[0017] The heat exchanger is connected to a tap water inlet pipe and a tap water outlet pipe, an electric regulating valve is installed on the tap water inlet pipe, a temperature sensor is installed on the tap water outlet pipe, and the electric regulating valve and the temperature sensor are both electrically connected to a control module.

[0018] In a further embodiment, it further comprises a dosing device, a dosing pipeline is connected between the dosing device and the water tank, a pH sensor is installed in the water tank, and the pH sensor is electrically connected to the control module.

[0019] The flue gas waste heat deep recovery system in the present invention, through the spray component that directly sprays and cools the flue gas, constitutes a primary heat exchange of the flue gas, can recover the heat in the flue gas into the spray water, effectively improves the heat transfer efficiency through direct gas-liquid contact, and can release the heat in the flue gas more fully.

[0020] The spray water after the flue gas is sprayed and cooled is stored in a water tank to realize the heat storage function. The circulating heat exchange component connected to the water tank can form secondary heat exchange, so that the heat storage energy of the spray water is transferred to the outside in the form of circulating heat exchange, which effectively reduces the temperature of the spray water after the heat is transferred. The spray water after heat exchange can be circulated to the spray component for the second time, which is more conducive to the direct recovery of flue gas heat and ensures the recovery effect of flue gas waste heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of the structure of a flue gas waste heat deep recovery system provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the internal structure of a housing and a water tank provided in an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of the spray assembly provided in the embodiment of the present application;

[0025] Figure 4 A schematic diagram of the structure of the bubble nozzle of the gas-liquid mixing device provided in an embodiment of the present application.

[0026] icon:

[0027] 1-shell; 2-circulation heat exchange component; 3-dosing device; 4-smoke outlet; 5-smoke channel; 6-smoke baffle; 6-1-high-temperature smoke baffle; 6-2-low-temperature smoke baffle; 7-smoke inlet; 8-spray assembly; 9-water tank cover; 10-high-temperature water tank; 11-low-temperature water tank; 12-spray gun body; 13-spray gun nozzle; 14-blind flange; 15-spray pipe; 16-electric regulating valve; 17- Temperature sensor; 18-tap water pipe; 18-1-tap water inlet pipe; 18-2-tap water outlet pipe; 19-heat exchanger; 20-circulation pump; 21-flange; 22-dosing pipe; 23-dosing pump; 24-liquid tank; 25-stirring pump; 26-bubble nozzle; 27-screw; 28-butterfly nozzle; 29-nut; 30-nozzle support block; 31-gas-liquid mixing sieve plate; 32-gas-liquid mixing branch pipe. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0030] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] See also Figure 1-Figure 4The flue gas waste heat deep recovery system provided in the embodiment of the present application includes: a shell 1, a flue gas channel 5 is arranged inside the shell 1, and a spray component 8 for spraying and cooling the flue gas is installed in the flue gas channel 5; a water tank for receiving spray water is arranged at the bottom of the shell 1, and the water tank is connected to a circulating heat exchange component 2 through a pipeline.

[0032] The flue gas waste heat deep recovery system in the present application is mainly used to recover the waste heat in the flue gas to solve the problem of white smoke emission from the flue gas while ensuring the effective utilization rate of the recovered heat.

[0033] Through the spray assembly 8 in the present application, the waste heat in the flue gas can be recovered in the form of primary heat exchange by spraying water directly on the flue gas, and the heat exchange efficiency can be greatly improved through the form of direct gas-liquid contact. At the same time, secondary emission reduction of the flue gas can be achieved by directly spraying the flue gas. The process of cooling the flue gas is accompanied by a large amount of condensation of water in the flue gas, and finally the "white smoke" phenomenon is basically eliminated.

[0034] The water tank for receiving the spray water arranged at the bottom of the shell 1 can perform secondary heat exchange recovery on the heat transferred to the spray water. By connecting the water tank to the circulating heat exchange component 2, the heat stored in the spray water in the water tank can be utilized in the form of external circulation. On the one hand, it can be used by heating the external water supply such as tap water during the external circulation heat exchange process. On the other hand, it can also reduce the temperature of the spray water when it circulates back to the spray component 8, thereby achieving the technical purpose of circulating the output of a low-temperature cold source and promoting the primary spray heat exchange effect.

[0035] The spray assembly 8 specifically includes a high temperature section spray assembly and a low temperature section spray assembly, and a flue gas baffle 6 is arranged between the high temperature section spray assembly and the low temperature section spray assembly. The flue gas high temperature section and the flue gas low temperature section can be distinguished by the arranged flue gas baffle 6, and a two-stage circulation heat exchange system of the high temperature section and the low temperature section can be formed, which can make fuller use of the heat in the flue gas, save energy, and effectively improve the heat exchange efficiency.

[0036] In this embodiment, two smoke baffles 6 spaced apart from each other are used to divide the smoke channel 5 into a high temperature section and a low temperature section. The smoke baffles 6 specifically include a high temperature smoke baffle 6-1 located at the bottom and a low temperature smoke baffle 6-2 located at the top.

[0037] A smoke inlet 7 is arranged on the side of the shell 1, a smoke outlet 4 is arranged on the top of the shell 1, a high-temperature smoke baffle 6-1 is arranged at a position adjacent to the smoke inlet 7, a high-temperature section spray assembly 6-2 is arranged on the inner side of the shell 1 of the smoke inlet 7, specifically between two smoke baffles 6, a low-temperature section spray assembly 8 is arranged at the lower part of the smoke outlet 4, and is located above the low-temperature smoke baffle 6-2, and the low-temperature smoke baffle 6-2 and the high-temperature smoke baffle 6-1 are both inclined at an angle of 30° to the horizontal plane. Through this arrangement, on the one hand, it can promote the formation of two-stage spraying of the high-temperature section and the low-temperature section, and on the other hand, it can make the two-stage spraying water fall into the high-temperature water tank 10 and the low-temperature water tank 11 at the bottom of the shell 1 respectively.

[0038] In order to enhance the contact between the spray water and the flue gas, so that the heat in the flue gas can be more fully absorbed, a gas-liquid mixing component is also arranged between the high-temperature section spray component and the low-temperature section spray component. The gas-liquid mixing component can form irregular turbulence of gas-liquid mixing to enhance the contact between the flue gas and the spray water. Specifically, the gas-liquid mixing component includes a bubble nozzle 26 and a gas-liquid mixing screen plate 31. The turbulent mixing of gas and liquid is formed by the cooperation between the two. The main purpose is to achieve a more complete fusion of flue gas and water, generate turbulent motion in the gas-liquid mixing field, and better improve the gas-liquid heat exchange, and improve the efficiency by more than 20%. The bubble nozzle 26 is installed on the side wall of the shell 1, and the gas-liquid mixing screen plate 31 is located below the bubble nozzle 26 and is arranged in the flue gas channel 5.

[0039] The low-temperature flue gas baffle 6-2 and the high-temperature flue gas baffle 6-1 in this embodiment are arranged alternately at intervals, and the low-temperature flue gas baffle 6-2 is connected to the gas-liquid mixing sieve plate 31. Specifically, the side of the low-temperature flue gas baffle 6-2 is connected to the side of the gas-liquid mixing sieve plate 31, and is connected to the inner wall of the shell 1 at the same time; the high-temperature flue gas baffle 6-1 is connected to the top of the water tank, and a smoke baffle is vertically arranged on the water tank opposite to the smoke inlet 7, and the high-temperature smoke gas baffle 6-1 is obliquely connected to the top of the smoke baffle. The low-temperature smoke gas baffle 6-2 and the high-temperature smoke gas baffle 6-1 can play a good diversion role, and respectively introduce the two-stage spray water into the two water tanks with different temperatures.

[0040] Combined with two inclined flue gas deflectors 6, the spray water generated by the high-temperature section spray assembly 8 can flow into the high-temperature water tank 10, while the spray water generated by the low-temperature section spray assembly 8 can flow into the low-temperature water tank 11, and the spray water is further circulated and cooled through the external circulation heat exchange assembly 2.

[0041] The circulating heat exchange assembly 2 specifically includes two sets of circulating pumps 20 and heat exchangers 19, each set of circulating pumps 20 and heat exchangers 19 corresponds to the high-temperature water tank 10 and the low-temperature water tank 11 respectively. A spray pipe 15 is connected between the heat exchanger 19 and the shell 1, which is used to return the spray water after heat exchange cooling to the spray assembly 8. The spray assembly 8 includes a spray branch pipe connected to the spray pipe 15 and a nozzle installed on the spray branch pipe. The spray branch pipe and the spray pipe 15 are detachably connected through a flange 21. The spray branch pipe in this embodiment is specifically connected to the spray pipe 15 through a blind flange 21. The diameter of the spray branch pipe and the spray pipe 15 is much smaller than the diameter of the flange 21. The form of detachable connection through the blind flange 21 facilitates the disassembly and assembly of the spray assembly 8 on the one hand, and more importantly, the spray direction of the nozzle can be adjusted. Combined with the inclination direction of the flue gas baffle 6, the spray water can be introduced into the high-temperature water tank 10 and the low-temperature water tank 11 respectively while accurately cooling and spraying the incoming flue gas.

[0042] The spray water of the gas-liquid mixing assembly is also replenished through the spray pipe 15. The spray pipe 15 is connected to a gas-liquid mixing branch pipe 32. The bubble nozzle 26 is connected to the gas-liquid mixing branch pipe 32. A plurality of through holes are evenly distributed on the gas-liquid mixing sieve plate 31. The bubble nozzle 26 includes a butterfly nozzle 28 arranged below the low-temperature section spray assembly 8.

[0043] The heat exchanger 19 in the present invention includes a high-temperature section heat exchanger and a low-temperature section heat exchanger, and the spray pipe 15 includes a high-temperature section spray pipe 15 and a low-temperature section spray pipe 15 respectively connected to the high-temperature section heat exchanger and the low-temperature section heat exchanger, and the gas-liquid mixing branch pipe is specifically connected to the low-temperature section spray pipe 15 located above.

[0044] From the perspective of utilizing the heat of the spray water in the secondary heat exchange water tank, the heat exchanger 19 is connected to a tap water inlet pipe 18-1 and a tap water outlet pipe 18-2 to heat the tap water supplied from the outside. An electric regulating valve 16 is installed on the tap water inlet pipe 18-1 to replenish external water supply to the system. At the same time, a temperature sensor 17 is installed on the tap water outlet pipe 18-2 to monitor the temperature of the tap water after heating. The electric regulating valve 16 and the temperature sensor 17 are both electrically connected to the control module of the flue gas waste heat deep recovery system, which is used to automatically adjust whether the electric regulating valve 16 is opened through the control module, and to feedback the temperature of the tap water after heating.

[0045] Based on the structure of the above-mentioned flue gas waste heat deep recovery system, the composition and working principle of each part are described in detail below.

[0046] In the spraying part of the primary heat exchange, pressure level gauges are respectively provided inside the high-temperature water tank 10 and the low-temperature water tank 11 for level measurement. The two groups of water tanks are respectively connected to the circulating pump 20 by water pipes, and the water in the water tanks is self-circulated through the circulating pump 20. A water tank cover 9 is provided on the upper side of the water tank outside the shell 1, and an opening directly connected to the smoke channel 5 is provided on the top of the water tank inside the shell. A smoke inlet 7 is provided on the side below the shell 1, and a smoke outlet 4 is provided on the top of the shell 1. The smoke inlet 7 and the smoke outlet 4 are both open wide-mouth structures, and the wide-mouth design facilitates the collection and discharge of smoke. Two groups of heat exchange spray components 8 are embedded in the smoke channel 5, and two smoke baffles 6 are built in the middle at an angle of 30° to the horizontal plane.

[0047] The inside of the shell 1 is divided from top to bottom into: a flue gas low temperature section, a low temperature flue gas baffle 6-2, a flue gas high temperature section, a low temperature water tank 11 and a high temperature water tank 10. The high temperature heat exchange zone and the low temperature heat exchange zone are divided by a flue gas baffle 6. The high temperature flue gas enters the high temperature section in the flue gas channel 5 through the flue gas inlet 7. Under the effect of the water droplet spray of the high temperature section spray assembly 8, the first cooling is achieved, and the water with a higher temperature flows into the high temperature water tank 10 along the high temperature flue gas baffle 6-1. The flue gas then enters the low temperature section. In order to achieve a more complete fusion of the flue gas and water and produce turbulent fusion, a gas-liquid mixing assembly composed of a bubble nozzle 26 and a gas-liquid mixing screen plate 31 is provided in the low temperature zone. The cooperation of the two constitutes a turbulent fusion device in the present invention, which can better improve the gas-liquid heat exchange and improve the efficiency by more than 20%.

[0048] The working principle is the same as that of the high temperature zone. Under the action of the low temperature section spray assembly 8, the low temperature spray water with a certain temperature is obtained through spray heat exchange and flows into the low temperature water tank 11. By scientifically separating the high temperature section and the low temperature section inside the shell 1, the required heat exchange of high temperature and low temperature is realized, and the energy saving effect is further guaranteed. At the same time, the internally designed gas-liquid mixing assembly and the spray assembly 8 realize the direct contact between the flue gas and the spray water. Compared with the traditional indirect heat exchange form, the heat exchange efficiency is greatly improved, and the waste heat utilization rate is also greatly improved.

[0049] The high temperature section spray assembly 8 and the low temperature section spray assembly 8 each include a spray gun body 12 formed by a spray branch pipe, a spray gun nozzle and a blind flange 14. Each spray assembly 8 is provided with two spray gun bodies 12, and each spray gun body 12 is provided with two spray gun nozzles 13. The spray gun nozzle 13 is made of 316L stainless steel, and the spray angle is designed to be 105°, which can more fully cover the flue gas channel 5 and improve the spraying effect. The spray gun body 12 is connected to the spray pipe 15 through the blind flange 14 and fixed by bolts, which is convenient for disassembly and cleaning, and has good sealing performance, and is convenient for adjusting the spray angle of the spray gun nozzle 13.

[0050] The spray gun nozzle 13 of the present invention sprays in a solid cone composed of small water droplets. Compared with the traditional hollow cone, this spraying effect has a better spraying effect and can increase the contact area between the small water droplets and the flue gas, thereby reducing the flue gas temperature. Four spray gun nozzles 13 are arranged in the low-temperature heat exchange zone and the high-temperature heat exchange zone respectively, which can effectively cover the entire low-temperature heat exchange zone and the high-temperature heat exchange zone, achieving the effect of no dead angle in the heat exchange zone, and can further improve the heat exchange efficiency between the flue gas and water.

[0051] The gas-liquid mixing device of the primary heat exchange part mainly includes a bubble nozzle 26 and a gas-liquid mixing screen plate 31, wherein the bubble nozzle 26 is connected to a gas-liquid mixing branch pipe, the bubble nozzle 26 is connected to the end of the gas-liquid mixing branch pipe, and is fixed by a nozzle support block 30. The bubble nozzle 26 in this embodiment is specifically a butterfly nozzle 28, and is fixed on the nozzle support block 30 by a screw 27 and a nut 29. The bubble nozzle 26 mainly sprays spray water in the horizontal direction.

[0052] The main structure of the gas-liquid mixing sieve plate 31 is a metal plate, on which there are evenly distributed pores in the form of through holes. The flue gas continues to rise through the gas-liquid mixing sieve plate 31 in the low-temperature section of the flue gas, and mixes with the horizontal spray water of a certain pressure ejected by the bubble nozzle 26, forming irregular turbulence, avoiding the separate flow of the two fluids, so that the flue gas and the spray water will not form their own channels, and the contact effect of the gas-liquid two phases is further guaranteed. In addition, turbulence will increase the mixing area and achieve more sufficient heat exchange.

[0053] The gas-liquid mixing sieve plate 31 is made of acid- and alkali-resistant 316L stainless steel, and a circular through hole is processed by a CNC laser cutting machine. The through hole diameter is 15mm, and the center distance between the through holes is 17mm. The through hole allows flue gas and spray water to pass through. The spray water is sprayed from the spray gun nozzle and the bubble nozzle 26. The solution drops to the gas-liquid mixing sieve plate 31 and contacts the flue gas in reverse. The spray water forms a splashing state similar to water splashes in the collision zone and splashes around. The tiny water droplets formed by the splashing contact the flue gas passing through the through hole, adsorbing the particulate matter in the flue gas, and absorbing the heat in the flue gas into the spray water droplets, so that the spray water and the flue gas are fully mixed, thereby achieving more sufficient heat exchange.

[0054] The secondary heat exchange part mainly includes a water supply pipeline, a plate heat exchanger 19, a circulation pump 20, a tap water pipeline 18 and a spray pipe 15. The tap water pipeline 18 includes a tap water inlet pipeline 18-1 and a tap water outlet pipeline 18-2. An electric regulating valve 16 is installed on the tap water inlet pipeline 18-1, and a temperature sensor 17 is installed on the tap water outlet pipeline 18-2.

[0055] Two parallel groups of circulation pumps 20 are connected to the plate heat exchanger 19 through pipes and sealed by flanges 21. One end of the plate heat exchanger 19 is connected to the spray assembly 8 through a spray pipe 15 to provide spray water; the other end is connected to the tap water pipe 18, and an electric regulating valve 16 is installed on the tap water inlet pipe 18-1, and a temperature sensor 17 is installed on the tap water outlet pipe 18-2. The temperature sensor 17 in this embodiment is specifically a PT100 platinum thermal resistor, which controls the tap water supply and monitors the outlet water temperature of the tap water after secondary heat exchange.

[0056] The high-temperature water tank 10 and the low-temperature water tank 11 are respectively equipped with pressure level gauges, which transmit the 4-20mA current signal of the liquid level to the PLC controller (programmable controller), and then give an output signal through the PLC program parameter setting value, which is transmitted to the automatic water replenishment electric regulating valve 16 for water replenishment. The water in the water tank will be pumped to the plate heat exchanger 19 through the circulation pump 20 for heat energy replacement, and the residual heat will be used for tap water heating to achieve secondary utilization of flue gas heat. At the same time, part of the heated water will be transported to the spray assembly 8 through the spray pipe 15 for spray heat exchange in the primary heat exchange process.

[0057] The flue gas waste heat deep recovery system of the present invention further comprises a dosing device 3, which is specifically a liquid medicine tank 24 with a stirring pump 25 disposed on the top, and a dosing pipeline 22 is connected between the liquid medicine tank 24 and the water tank.

[0058] The lower side of the medicine liquid tank 24 is connected to the dosing pump 23 through the dosing pipe 22 . Two branches are arranged at the output port of the dosing pipe 22 , leading to the high temperature water tank 10 and the low temperature water tank 11 respectively.

[0059] The water tank dosing device 3 transmits the pH data measured by the invasive pH sensor (not shown in the figure) installed in the water tank to the PLC controller in real time, and then the PLC program controls the setting of parameters and gives a control signal to start the electric regulating valve 16. After the liquid medicine in the liquid medicine tank 24 is evenly mixed by the stirring pump 25, the liquid medicine in the liquid medicine tank 24 is pumped to the water tank by the dosing pump 23, completing the automatic dosing function to balance the pH of the water.

[0060] The flue gas waste heat deep recovery system of the present invention, based on the primary heat exchange of spray heat exchange and the secondary heat absorption of external circulation heat exchange, can reduce the exhaust temperature to 20°C and improve the energy utilization rate of the original system by 7%-10%; at the same time, by using the direct contact spray form, the secondary emission reduction of the flue gas can be achieved. The process of flue gas cooling is accompanied by a large amount of condensation of water in the flue gas, and finally the "white smoke" phenomenon is basically eliminated.

[0061] It should be noted that, in the absence of conflict, the features in the embodiments of this application may be combined with each other.

[0062] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A flue gas waste heat deep recovery system, characterized in that: Includes: housing, A smoke channel is arranged inside the shell, and a spray component for spraying and cooling the smoke is installed in the smoke channel; A water tank for receiving spray water is provided at the bottom of the shell, and the water tank is connected to a circulating heat exchange component through a pipeline; The spray assembly includes a high-temperature section spray assembly and a low-temperature section spray assembly, and a smoke baffle is arranged between the high-temperature section spray assembly and the low-temperature section spray assembly; The side of the shell is provided with a smoke inlet, the top of the shell is provided with a smoke outlet, the high-temperature section spray assembly is provided on the inner side of the smoke inlet, and the low-temperature section spray assembly is provided at the lower part of the smoke outlet; A gas-liquid mixing component is also provided between the high-temperature section spray component and the low-temperature section spray component, and the gas-liquid mixing component includes a bubble nozzle and a gas-liquid mixing screen plate, the bubble nozzle is installed on the side wall of the shell, and the gas-liquid mixing screen plate is located below the bubble nozzle and is provided in the smoke channel; The smoke baffles include two staggered ones, each of which is inclined relative to the horizontal plane, one of which is connected to the bottom of the gas-liquid mixing sieve plate, and the other is connected to the top of the water tank.

2. The flue gas waste heat deep recovery system according to claim 1 is characterized in that: The water tank includes a high-temperature water tank and a low-temperature water tank for receiving spray water from the high-temperature section spray assembly and the low-temperature section spray assembly, and the circulating heat exchange assembly includes a circulating pump and a heat exchanger respectively arranged corresponding to the high-temperature water tank and the low-temperature water tank.

3. The flue gas waste heat deep recovery system according to claim 2 is characterized in that: A spray pipe is connected between the heat exchanger and the shell. The spray assembly includes a spray branch pipe connected to the spray pipe and a nozzle installed on the spray branch pipe. The spray branch pipe is detachably connected to the spray pipe through a flange.

4. The flue gas waste heat deep recovery system according to claim 3 is characterized in that: The spray pipe is connected to a gas-liquid mixing branch pipe, the bubble nozzle is connected to the gas-liquid mixing branch pipe, a plurality of through holes are evenly distributed on the gas-liquid mixing screen plate, and the bubble nozzle includes a butterfly nozzle arranged below the low-temperature section spray assembly.

5. The flue gas waste heat deep recovery system according to claim 3 is characterized in that: The heat exchanger includes a high-temperature section heat exchanger and a low-temperature section heat exchanger, and the spray pipe includes a high-temperature section spray pipe and a low-temperature section spray pipe respectively connected to the high-temperature section heat exchanger and the low-temperature section heat exchanger; The heat exchanger is connected to a tap water inlet pipe and a tap water outlet pipe, an electric regulating valve is installed on the tap water inlet pipe, a temperature sensor is installed on the tap water outlet pipe, and the electric regulating valve and the temperature sensor are both electrically connected to a control module.

6. The flue gas waste heat deep recovery system according to claim 5, characterized in that: It also includes a dosing device, a dosing pipeline is connected between the dosing device and the water tank, a pH sensor is installed in the water tank, and the pH sensor is electrically connected to the control module.

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