Efficient and energy-saving carnallite recycling tail gas treatment system
By designing a highly efficient and energy-saving miscellaneous salt resource-based exhaust gas treatment system, pressurized heating and SCR technology are used to remove NOx and dioxin gases in the exhaust gas and heat exchange, the problems of high energy consumption and unused heat in the prior art are solved, and the cost reduction and toxic gas degradation are achieved.
Patent Information
- Application Number
- CN202411887416.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-03-07
AI Technical Summary
When dealing with miscellaneous salt resourced exhaust gas, the prior art has problems such as high energy consumption, high cost of activated carbon adsorption, and failure to effectively utilize the thermal energy of high-temperature flue gas.
A highly efficient and energy-saving miscellaneous salt resource-based exhaust gas treatment system is designed, including a dust removal unit, a flue gas waste heat utilization unit, a SCR treatment unit and a flue gas purification unit. By pressurized heating of the flue gas and exchanging heat with the material, the NOx and dioxin gas are removed by using SCR technology, and the flue gas after secondary heat exchange is purified and discharged.
It effectively reduces the use of saturated steam in the evaporation system, the power consumption of the compressor operation and the energy consumption of the boiler, reduces the operating costs, and realizes the degradation of toxic gases in the flue gas, reducing the cost of disposing of activated carbon.
Smart Images
Figure CN119573068A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a highly efficient and energy-saving waste salt resource tail gas treatment system, belonging to the technical field of tail gas treatment. Background Art
[0002] At present, in the process of heat treatment (pyrolysis, incineration, etc.) of miscellaneous salt resource utilization, in order to avoid the generation of dioxin-like toxic and harmful gases (dioxin generation temperature 200~500℃), the flue gas is usually transported to the secondary combustion chamber for high-temperature decomposition, and the outlet flue gas temperature of the waste heat utilization device (such as waste heat boiler) in the process is controlled at about 550℃, and then enters the flue gas treatment system to be quickly cooled to below 200℃ for purification and discharge. The boiling point of organic matter is generally 100~600℃, so the high-temperature exhaust gas at the outlet of the waste heat boiler generally contains organic matter and heavy metal impurities. In actual production, in order to prevent the flue gas from regenerating dioxin-like toxic and harmful gases, the flue gas will first decompose the organic matter by high-temperature incineration (1100℃, stay for 2s), and then enter the denitrification, rapid cooling absorption, deacidification, dust removal and other treatment steps. The rapid cooling absorption tower can reduce the temperature of high-temperature flue gas to 200°C or below within 1 second, ensuring that the flue gas stays at the dioxin generation temperature for the shortest possible time. At the same time, the flue gas purification system is equipped with activated carbon adsorption, and then it is directly discharged after deacidification and flue gas dewhitening.
[0003] It can be seen that in order to meet the gas emission index of dioxins in the traditional process, a lot of energy consumption is added, and the activated carbon adsorption process in the traditional process can only adsorb toxic gases but cannot effectively degrade them, which in turn increases the disposal cost of adsorbed saturated activated carbon. In addition, the high-temperature flue gas is directly discharged after treatment, and a large amount of heat energy in it cannot be utilized. Selective catalytic reduction technology (SCR) refers to the use of reducing agents (such as NH3, urea) to selectively react with NOx in flue gas to generate non-toxic and non-polluting nitrogen and water under the action of a catalyst. And when the reaction temperature is around 300°C, the SCR process has a strong synergistic removal ability for NOx and dioxins, and can effectively remove both. In addition, in the evaporation process, in order to make the material reach the specified temperature, a large amount of electricity consumption and saturated steam consumption will be generated, resulting in excessively high operating and production costs. Therefore, it is of great significance to develop a treatment solution for high-temperature flue gas that effectively utilizes impure salt resources. Summary of the invention
[0004] In view of the deficiencies in the prior art, the present invention provides an efficient and energy-saving tail gas treatment system for recycling impure salt resources, which can not only remove NOx and dioxin gases in flue gas and avoid the risk of dioxin gases being generated in exhaust gas due to temperature reduction, but also utilize the heat energy in high-temperature flue gas, thereby reducing the energy consumption and operating costs of high-temperature decomposition and other evaporative heating.
[0005] The technical solution of the present invention to solve the above technical problems is as follows: an efficient and energy-saving waste salt resource tail gas treatment system, comprising a dust removal unit, a flue gas waste heat utilization unit, an SCR treatment unit and a flue gas purification unit; The inlet end of the dust removal unit is connected to the waste heat boiler through a flue gas pipe, and the dust removal unit is used to capture and remove dust from particles in the flue gas transported by the flue gas pipe; The outlet end of the dust removal unit is connected to the flue gas waste heat utilization unit through a conveying pipeline, and the flue gas waste heat utilization unit is used to pressurize and heat the flue gas conveyed by the dust removal unit, and the flue gas waste heat utilization unit is also used to perform the first heat exchange between the pressurized and heated flue gas and the material; The inlet end of the SCR processing unit is connected to the flue gas waste heat utilization unit through a transmission pipeline, and the SCR processing unit is used to remove NOx and dioxins from the flue gas transmitted by the flue gas waste heat utilization unit; The outlet end of the SCR processing unit is connected to the flue gas waste heat utilization unit via a conveying pipeline, and the flue gas waste heat utilization unit is also used to perform secondary heat exchange between the flue gas conveyed by the SCR processing unit and the material; The flue gas waste heat utilization unit is also connected to the flue gas purification unit via a transmission pipeline, and the flue gas purification unit purifies and discharges the flue gas after the secondary heat exchange transmitted by the flue gas waste heat utilization unit.
[0006] As a preferred solution for an efficient and energy-saving waste salt resource recovery tail gas treatment system, the dust removal unit includes a high-temperature dust collector, and the dust removal unit captures and removes dust from particles in the flue gas transported by the flue gas pipe through the high-temperature dust collector.
[0007] As a preferred solution for the high-efficiency and energy-saving waste salt resource tail gas treatment system, the flue gas waste heat utilization unit includes a gas storage heating box; The outlet end of the dust removal unit is connected to the gas storage and heating box of the flue gas waste heat utilization unit through a conveying pipeline, and the flue gas waste heat utilization unit pressurizes and heats the flue gas conveyed by the dust removal unit through the gas storage and heating box.
[0008] As a preferred solution for the high-efficiency and energy-saving waste salt resource tail gas treatment system, the flue gas waste heat utilization unit also includes a front-stage heat exchanger; The gas storage and heating box is connected to the front-stage heat exchanger through a conveying pipeline, and the flue gas waste heat utilization unit performs the first heat exchange between the flue gas pressurized and heated by the gas storage and heating box and the material through the front-stage heat exchanger.
[0009] As an optimal solution for an efficient and energy-saving waste salt resource exhaust gas treatment system, the flue gas waste heat utilization unit also includes a post-stage heat exchanger; the outlet end of the SCR treatment unit is connected to the post-stage heat exchanger of the flue gas waste heat utilization unit via a conveying pipeline, and the flue gas waste heat utilization unit performs secondary heat exchange between the flue gas and the material transported by the SCR treatment unit through the post-stage heat exchanger.
[0010] As a preferred solution for the high-efficiency and energy-saving salt resource recovery tail gas treatment system, the front-stage heat exchanger and the rear-stage heat exchanger both adopt horizontal cylindrical heat exchangers, and fluid channels are left between the plates of the front-stage heat exchanger and the rear-stage heat exchanger, and the plates of the front-stage heat exchanger and the rear-stage heat exchanger are both corrugated; The internal flue gas flow directions of the front-stage heat exchanger and the rear-stage heat exchanger are opposite to the material flow direction.
[0011] As an optimal solution for the efficient and energy-saving waste salt resource tail gas treatment system, the flue gas temperature after the flue gas pressurized and heated by the gas storage and heating box and the first heat exchange with the material is 300°C; The temperature of the flue gas after the secondary heat exchange between the flue gas transported by the SCR processing unit and the material is lower than 100°C.
[0012] As an optimal solution for the efficient and energy-saving waste salt resource recovery tail gas treatment system, a gas booster pump is provided on the air inlet flue of the gas storage heating box; a pressure gauge and a pneumatic pressure control valve are provided at the outlet of the gas storage heating box, and when the pressure in the gas storage heating box reaches a fixed value, the pneumatic pressure control valve is opened to release the high-temperature gas.
[0013] As a preferred solution for the high-efficiency and energy-saving tail gas treatment system for recycling impure salt resources, the SCR treatment unit includes an SCR reactor, an evaporator, an ammonia storage tank, a buffer tank and a mixer; The ammonia storage tank is connected to the evaporator through a delivery pipeline, and the evaporator is used to vaporize the liquid ammonia stored inside the ammonia storage tank; the evaporator is connected to the buffer tank through a delivery pipeline, the buffer tank is connected to the mixer through a delivery pipeline, and the mixer is connected to the inlet end of the SCR reactor through a delivery pipeline.
[0014] As a preferred solution for the high-efficiency and energy-saving waste salt resource tail gas treatment system, the flue gas purification unit includes a deacidification device and a flue gas dewhitening device; The inlet end of the deacidification equipment is connected to the outlet end of the subsequent heat exchanger through a delivery pipeline, and the deacidification equipment is used to perform deacidification treatment on the flue gas delivered by the subsequent heat exchanger; The flue gas dewhitening equipment is connected to the deacidification equipment through a conveying pipeline, and the flue gas dewhitening equipment is used to dewhiten the flue gas after deacidification treatment by the deacidification equipment.
[0015] The beneficial effects of the present invention are as follows: since the inlet end of the dust removal unit is connected to the waste heat boiler through the flue gas pipe, the dust removal unit is used to capture and remove dust from particles in the flue gas transported by the flue gas pipe; the outlet end of the dust removal unit is connected to the flue gas waste heat utilization unit through a conveying pipeline, the flue gas waste heat utilization unit is used to pressurize and heat the flue gas transported by the dust removal unit, and the flue gas waste heat utilization unit is also used to perform a first heat exchange between the pressurized and heated flue gas and the material; the inlet end of the SCR treatment unit is connected to the flue gas waste heat utilization unit through a conveying pipeline, the SCR treatment unit is used to remove NOx and dioxins from the flue gas transported by the flue gas waste heat utilization unit; the outlet end of the SCR treatment unit is connected to the flue gas waste heat utilization unit through a conveying pipeline, the flue gas waste heat utilization unit is also used to perform a secondary heat exchange between the flue gas transported by the SCR treatment unit and the material; the flue gas waste heat utilization unit is also connected to the flue gas purification unit through a conveying pipeline, the flue gas purification unit purifies and discharges the flue gas transported by the flue gas waste heat utilization unit after the secondary heat exchange. The present invention can effectively reduce the usage of saturated steam in the evaporation system, the power consumption of the compressor and the energy consumption of the boiler, and can reduce the operating cost while making full use of the high-temperature flue gas generated by the resource utilization of mixed salts. It can not only realize energy resource utilization, but also degrade toxic gases in the flue gas, reduce the disposal cost of adsorbed saturated activated carbon, and its heat energy can also be reused in the evaporation system, reducing the energy consumption of the evaporation system. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.
[0017] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.
[0018] Figure 1 A schematic diagram of the structure of an efficient and energy-saving tail gas treatment system for recycling of impure salts provided in an embodiment of the present invention; Figure 2 A schematic cross-sectional view of a heat exchanger in a highly efficient and energy-saving waste salt resource recovery tail gas treatment system provided in an embodiment of the present invention.
[0019] In the figure, 1. dust removal unit; 2. flue gas waste heat utilization unit; 3. SCR treatment unit; 4. flue gas purification unit; 5. waste heat boiler; 6. high-temperature dust collector; 7. gas storage heating box; 8. front-stage heat exchanger; 9. rear-stage heat exchanger; 10. SCR reactor; 11. evaporator; 12. ammonia storage tank; 13. buffer tank; 14. mixer; 15. deacidification equipment; 16. flue gas dewhitening equipment. DETAILED DESCRIPTION
[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.
[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0022] See also Figure 1 , the embodiment of the present invention provides an efficient and energy-saving waste salt resource tail gas treatment system, including a dust removal unit 1, a flue gas waste heat utilization unit 2, an SCR treatment unit 3 and a flue gas purification unit 4; The inlet end of the dust removal unit 1 is connected to the waste heat boiler 5 through a flue gas pipe, and the dust removal unit 1 is used to capture and remove dust from particles in the flue gas transported by the flue gas pipe; the outlet end of the dust removal unit 1 is connected to the flue gas waste heat utilization unit 2 through a transport pipeline, and the flue gas waste heat utilization unit 2 is used to pressurize and heat the flue gas transported by the dust removal unit 1, and the flue gas waste heat utilization unit 2 is also used to perform the first heat exchange between the pressurized and heated flue gas and the material; The inlet end of the SCR processing unit 3 is connected to the flue gas waste heat utilization unit 2 through a conveying pipeline, and the SCR processing unit 3 is used to remove NOx and dioxins from the flue gas conveyed by the flue gas waste heat utilization unit 2; the outlet end of the SCR processing unit 3 is connected to the flue gas waste heat utilization unit 2 through a conveying pipeline, and the flue gas waste heat utilization unit 2 is also used to perform secondary heat exchange between the flue gas conveyed by the SCR processing unit 3 and the material; The flue gas waste heat utilization unit 2 is also connected to the flue gas purification unit 4 via a transmission pipeline, and the flue gas purification unit 4 purifies and discharges the flue gas after the secondary heat exchange transmitted by the flue gas waste heat utilization unit 2 .
[0023] In this embodiment, the dust removal unit 1 includes a high-temperature dust collector 6, and the dust removal unit 1 captures and removes particles in the flue gas transported by the flue gas pipe through the high-temperature dust collector 6. The flue gas waste heat utilization unit 2 includes a gas storage and heating box 7; the outlet end of the dust removal unit 1 is connected to the gas storage and heating box 7 of the flue gas waste heat utilization unit 2 through a conveying pipeline, and the flue gas waste heat utilization unit 2 pressurizes and heats the flue gas transported by the dust removal unit 1 received through the gas storage and heating box 7. The flue gas waste heat utilization unit 2 also includes a front-stage heat exchanger 8; the gas storage and heating box 7 is connected to the front-stage heat exchanger 8 through a conveying pipeline, and the flue gas waste heat utilization unit 2 performs the first heat exchange between the flue gas pressurized and heated by the gas storage and heating box 7 and the material through the front-stage heat exchanger 8. The flue gas waste heat utilization unit 2 also includes a post-stage heat exchanger 9; the outlet end of the SCR processing unit 3 is connected to the post-stage heat exchanger 9 of the flue gas waste heat utilization unit 2 through a conveying pipeline, and the flue gas waste heat utilization unit 2 performs secondary heat exchange between the flue gas and the material conveyed by the SCR processing unit 3 through the post-stage heat exchanger 9.
[0024] In this embodiment, the temperature of the flue gas after the pressurized and heated flue gas of the gas storage and heating box 7 and the material undergo the first heat exchange is 300°C; the temperature of the flue gas after the secondary heat exchange between the flue gas delivered by the SCR processing unit 3 and the material by the subsequent heat exchanger 9 is lower than 100°C. A gas booster pump is provided on the air inlet flue of the gas storage and heating box 7; a pressure gauge and a pneumatic pressure control valve are provided at the outlet of the gas storage and heating box 7, and the pneumatic pressure control valve is opened to release the high-temperature gas when the pressure in the gas storage and heating box 7 reaches a fixed value.
[0025] In this embodiment, the SCR processing unit 3 includes an SCR reactor 10, an evaporator 11, an ammonia storage tank 12, a buffer tank 13 and a mixer 14; the ammonia storage tank 12 is connected to the evaporator 11 through a delivery pipeline, and the evaporator 11 is used to vaporize the liquid ammonia stored in the ammonia storage tank 12; the evaporator 11 is connected to the buffer tank 13 through a delivery pipeline, the buffer tank 13 is connected to the mixer 14 through a delivery pipeline, and the mixer 14 is connected to the inlet end of the SCR reactor 10 through a delivery pipeline. The flue gas purification unit 4 includes a deacidification device 15 and a flue gas deoxidation device 16; the inlet end of the deacidification device 15 is connected to the outlet end of the rear-stage heat exchanger 9 through a delivery pipeline, and the deacidification device 15 is used to deacidify the flue gas transported by the rear-stage heat exchanger 9; the flue gas deoxidation device 16 is connected to the deacidification device 15 through a delivery pipeline, and the flue gas deoxidation device 16 is used to deoxidize the flue gas after the deacidification treatment of the deacidification device 15.
[0026] The operating principle of the high-efficiency and energy-saving tail gas treatment system for recycling of impure salts according to the embodiment of the present invention is as follows: The flue gas first passes through the dust removal unit 1 and the high-temperature dust collector 6 for dust removal. The particles in the flue gas may absorb a large amount of dioxins. The high-temperature dust collector 6 can perform preliminary purification of the flue gas and reduce the wear and blockage of the system by the particles. After passing through the high-temperature dust collector 6, it enters the flue gas waste heat utilization unit 2.
[0027] Among them, the flue gas enters the gas storage heating box 7 of the flue gas waste heat utilization unit 2 through the air intake flue, and the gas booster pump on the air intake flue performs work on the gas transported to the gas storage heating box 7, pressurizing the gas in the gas storage heating box 7 to increase the temperature. A pressure gauge and a pneumatic pressure control valve are provided at the outlet of the gas storage heating box 7 to control the pressure in the gas storage heating box 7. When the pressure in the gas storage heating box 7 reaches a fixed value, the pneumatic pressure control valve automatically opens to release high-temperature gas. After the flue gas is heated in the gas storage heating box 7, it carries higher heat energy and enters the front-stage heat exchanger 8 of the flue gas waste heat utilization unit 2 for heat exchange to heat the material.
[0028] When the flue gas temperature of the front-stage heat exchanger 8 drops to about 300°C, the flue gas is passed to the SCR processing unit 3. The ammonia storage tank 12 in the SCR processing unit 3 stores 15 days of liquid ammonia. When used, the liquid ammonia is vaporized by the evaporator 11 and then enters the SCR reactor 10 through the ammonia buffer tank 13 and the mixer 14. Ammonia is evenly distributed and mixed with the flue gas above the SCR reactor 10 through a spray device. After mixing, the flue gas uses the vanadium tungsten titanium SCR process catalyst to synergistically remove NOx and dioxins. After the flue gas reacts in the SCR reactor 10, it continues to pass to the rear-stage heat exchanger 9 of the flue gas waste heat utilization unit 2. After passing through multiple rear-stage heat exchangers 9, the flue gas temperature drops below 100°C, and the heat energy in the flue gas is fully utilized and transported to the flue gas purification unit 4. The flue gas transported by the rear-stage heat exchanger 9 is deacidified by the deacidification equipment 15; the flue gas deacidification equipment 16 is used to deacidify the flue gas after the deacidification treatment of the deacidification equipment 15. After being purified and meeting the standards, this part of high-temperature flue gas is discharged. The thermal energy utilization of this part of high-temperature flue gas can reduce the amount of saturated steam used in the evaporation system and save the electricity consumption cost of steam and evaporation boilers.
[0029] See also Figure 2 In a possible embodiment, the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 are both horizontal cylindrical heat exchangers, fluid channels are left between the plates of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9, and the plates of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 are both corrugated; the internal flue gas flow direction of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 is opposite to the material flow direction.
[0030] Specifically, the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 are equipped with multiple horizontal cylindrical heat exchangers. The front-stage heat exchanger 8 and the rear-stage heat exchanger 9 are horizontal cylindrical, and there are channels between the two plates for the fluid to pass through. The plates are corrugated. This arrangement increases the turbulent state of the fluid while increasing the heat exchange area, thereby improving the heat transfer efficiency and heat exchange efficiency. The high-temperature flue gas is heat-exchanged step by step through multiple front-stage heat exchangers 8 and rear-stage heat exchangers 9. It should be noted that the flue gas flow direction is opposite to the material flow direction. Among them, the number of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 is determined according to the size of the flue gas temperature after heat exchange.
[0031] In a possible embodiment, the pneumatic pressure control valve should have both a pressure switch and a manual switch. The pressure switch is used for normal working conditions, and the manual switch is used for cleaning and maintenance.
[0032] In a possible embodiment, the front-stage heat exchanger 8, the rear-stage heat exchanger 9 and the SCR processing unit 3 are connected in series, so as to remove NOx, dioxins and multi-stage heat exchange. In the above embodiment, a plurality of front-stage heat exchangers 8 and rear-stage heat exchangers 9 are connected in series. In actual work, the number of series connections can be selectively increased or decreased according to actual working conditions.
[0033] In a possible embodiment, a temperature meter is provided between the front-stage heat exchanger 8, the rear-stage heat exchanger 9 and the SCR processing unit 3 to monitor the flue gas temperature entering and leaving the SCR processing unit 3. The temperature meter displays the heat exchange temperature of each stage in real time, monitors the real-time working conditions, and makes timely adjustments.
[0034] In a possible embodiment, the heat exchange cylinder shell of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9 can use an integrated shell made of heat-insulating material, and the cylinder covers on both sides are respectively provided with an air inlet, a feed inlet, an air outlet, and a feed outlet, and the cylinder cover seal is fixed with symmetrical fixing bolts.
[0035] In a possible embodiment, after long-term use, impurities in the flue gas may be deposited at the bottom of the front-stage heat exchanger 8 and the rear-stage heat exchanger 9, affecting the heat exchange efficiency. At this time, the pressure valve can be opened, and a fan can be used to supply air for flushing, and a smoke collection port can be installed under the front-stage heat exchanger 8 and the rear-stage heat exchanger 9.
[0036] In summary, the inlet end of the dust removal unit 1 of the present invention is connected to the waste heat boiler 5 through the flue gas pipe, and the dust removal unit 1 is used to capture and remove dust from the particles in the flue gas transported by the flue gas pipe; the outlet end of the dust removal unit 1 is connected to the flue gas waste heat utilization unit 2 through the conveying pipeline, and the flue gas waste heat utilization unit 2 is used to pressurize and heat the flue gas transported by the dust removal unit 1, and the flue gas waste heat utilization unit 2 is also used to perform the first heat exchange between the pressurized and heated flue gas and the material; the inlet end of the SCR treatment unit 3 ... The SCR treatment unit 3 is used to remove NOx and dioxins from the flue gas transported by the flue gas waste heat utilization unit 2; the outlet of the SCR treatment unit 3 is connected to the flue gas waste heat utilization unit 2 through a conveying pipeline, and the flue gas waste heat utilization unit 2 is also used to perform secondary heat exchange between the flue gas transported by the SCR treatment unit 3 and the material; the flue gas waste heat utilization unit 2 is also connected to the flue gas purification unit 4 through a conveying pipeline, and the flue gas purification unit 4 purifies and discharges the flue gas after the secondary heat exchange transported by the flue gas waste heat utilization unit 2. The flue gas first passes through the dust removal unit 1 to obtain a high-temperature dust collector 6 for dust removal. The particles in the flue gas may absorb a large amount of dioxin-like substances. The dust removal of the high-temperature dust collector 6 can perform preliminary purification of the flue gas and reduce the wear and fouling of the system by the particles. After passing through the high-temperature dust collector 6, it enters the flue gas waste heat utilization unit 2. The flue gas enters the gas storage and heating box 7 of the flue gas waste heat utilization unit 2 through the air intake flue. The gas booster pump on the air intake flue performs work on the gas transported to the gas storage and heating box 7, pressurizing the gas in the gas storage and heating box 7 to increase the temperature. A pressure gauge and a pneumatic pressure control valve are provided at the outlet of the gas storage and heating box 7 to control the pressure in the gas storage and heating box 7. When the pressure in the gas storage and heating box 7 reaches a fixed value, the pneumatic pressure control valve automatically opens to release high-temperature gas. After the flue gas is heated in the gas storage and heating box 7, it carries higher heat energy and enters the front-stage heat exchanger 8 of the flue gas waste heat utilization unit 2 for heat exchange to heat the material. When the flue gas temperature in the front-stage heat exchanger 8 drops to about 300°C, the flue gas passes to the SCR processing unit 3. The ammonia storage tank 12 in the SCR processing unit 3 stores 15 days of liquid ammonia. When used, the liquid ammonia is vaporized by the evaporator 11 and then enters the SCR reactor 10 through the ammonia buffer tank 13 and the mixer 14. Ammonia is evenly distributed and mixed with flue gas through a spray device above the SCR reactor 10. After mixing, the flue gas uses the vanadium-tungsten-titanium SCR process catalyst to remove NOx and dioxins synergistically. After the flue gas reacts in the SCR reactor 10, it continues to pass to the rear heat exchanger 9 of the flue gas waste heat utilization unit 2. After passing through multiple rear heat exchangers 9, the flue gas temperature drops below 100°C, and the heat energy in the flue gas is fully utilized and transported to the flue gas purification unit 4. The flue gas transported by the rear heat exchanger 9 is deacidified by the deacidification equipment 15; the flue gas deacidification equipment 16 is used to deacidify the flue gas after the deacidification treatment of the deacidification equipment 15.After being purified and discharged to meet the standards, the heat energy utilization of this part of high-temperature flue gas can reduce the amount of saturated steam used in the evaporation system, saving the cost of steam and electricity consumption of evaporation boilers. The present invention can effectively reduce the use of saturated steam in the evaporation system, the power consumption of the compressor and the energy consumption of the boiler, while fully utilizing the high-temperature flue gas generated by the resource utilization of impure salts and reducing the operating cost, which can not only realize energy resource utilization; but also degrade toxic gases in the flue gas, reduce the disposal cost of adsorbed saturated activated carbon, and its heat energy can also be reused in the evaporation system, reducing the energy consumption of the evaporation system.
[0037] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0038] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. An efficient and energy-saving salt resource tail gas treatment system, characterized in that: It comprises a dust removal unit (1), a flue gas waste heat utilization unit (2), an SCR treatment unit (3) and a flue gas purification unit (4); The inlet end of the dust removal unit (1) is connected to the waste heat boiler (5) via a flue gas pipe, and the dust removal unit (1) is used to capture and remove dust from particles in the flue gas transported by the flue gas pipe; The outlet end of the dust removal unit (1) is connected to the flue gas waste heat utilization unit (2) via a conveying pipeline, and the flue gas waste heat utilization unit (2) is used to pressurize and heat the flue gas conveyed by the dust removal unit (1). The flue gas waste heat utilization unit (2) is also used to perform a first heat exchange between the pressurized and heated flue gas and the material; The inlet end of the SCR processing unit (3) is connected to the flue gas waste heat utilization unit (2) via a transmission pipeline, and the SCR processing unit (3) is used to remove NOx and dioxins from the flue gas transmitted by the flue gas waste heat utilization unit (2); The outlet end of the SCR processing unit (3) is connected to the flue gas waste heat utilization unit (2) via a conveying pipeline, and the flue gas waste heat utilization unit (2) is also used to perform secondary heat exchange between the flue gas conveyed by the SCR processing unit (3) and the material; The flue gas waste heat utilization unit (2) is also connected to the flue gas purification unit (4) via a transmission pipeline, and the flue gas purification unit (4) purifies and discharges the flue gas after secondary heat exchange that is transmitted by the flue gas waste heat utilization unit (2).
2. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 1 is characterized in that: The dust removal unit (1) comprises a high-temperature dust collector (6), and the dust removal unit (1) captures and removes particles in the flue gas transported by the flue gas pipe through the high-temperature dust collector (6).
3. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 1 is characterized in that: The flue gas waste heat utilization unit (2) comprises a gas storage and heating box (7); The outlet end of the dust removal unit (1) is connected to the gas storage and heating box (7) of the flue gas waste heat utilization unit (2) via a delivery pipeline, and the flue gas waste heat utilization unit (2) pressurizes and heats the flue gas delivered by the dust removal unit (1) via the gas storage and heating box (7).
4. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 3 is characterized in that: The flue gas waste heat utilization unit (2) further comprises a front-stage heat exchanger (8); The gas storage and heating box (7) is connected to the front-stage heat exchanger (8) via a conveying pipeline, and the flue gas waste heat utilization unit (2) performs a first heat exchange between the flue gas pressurized and heated by the gas storage and heating box (7) and the material via the front-stage heat exchanger (8).
5. The high-efficiency and energy-saving waste salt resource tail gas treatment system according to claim 4 is characterized in that: The flue gas waste heat utilization unit (2) further comprises a post-stage heat exchanger (9); the outlet end of the SCR processing unit (3) is connected to the post-stage heat exchanger (9) of the flue gas waste heat utilization unit (2) via a transmission pipeline, and the flue gas waste heat utilization unit (2) performs secondary heat exchange between the flue gas transported by the SCR processing unit (3) and the material through the post-stage heat exchanger (9).
6. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 5 is characterized in that: The front-stage heat exchanger (8) and the rear-stage heat exchanger (9) are both horizontal cylindrical heat exchangers, fluid channels are left between the plates of the front-stage heat exchanger (8) and the rear-stage heat exchanger (9), and the plates of the front-stage heat exchanger (8) and the rear-stage heat exchanger (9) are both corrugated; The internal flue gas flow directions of the front-stage heat exchanger (8) and the rear-stage heat exchanger (9) are opposite to the material flow direction.
7. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 6 is characterized in that: The temperature of the flue gas after the pressurized and heated flue gas in the gas storage and heating box (7) and the material undergoes the first heat exchange is 300° C.; The temperature of the flue gas after the secondary heat exchange between the flue gas transported by the SCR processing unit (3) and the material by the rear-stage heat exchanger (9) is lower than 100°C.
8. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 6 is characterized in that: A gas booster pump is provided on the air inlet flue of the gas storage and heating box (7); a pressure gauge and a pneumatic pressure control valve are provided at the outlet of the gas storage and heating box (7); when the pressure in the gas storage and heating box (7) reaches a fixed value, the pneumatic pressure control valve is opened to release high-temperature gas.
9. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 1 is characterized in that: The SCR processing unit (3) comprises an SCR reactor (10), an evaporator (11), an ammonia storage tank (12), a buffer tank (13) and a mixer (14); The ammonia storage tank (12) is connected to the evaporator (11) via a delivery pipeline, and the evaporator (11) is used to vaporize liquid ammonia stored in the ammonia storage tank (12); the evaporator (11) is connected to the buffer tank (13) via a delivery pipeline, the buffer tank (13) is connected to the mixer (14) via a delivery pipeline, and the mixer (14) is connected to the inlet end of the SCR reactor (10) via a delivery pipeline.
10. The high-efficiency and energy-saving tail gas treatment system for recycling impure salts according to claim 5, characterized in that: The flue gas purification unit (4) comprises a deacidification device (15) and a flue gas dewhitening device (16); The inlet end of the deacidification device (15) is connected to the outlet end of the subsequent heat exchanger (9) via a delivery pipeline, and the deacidification device (15) is used to perform deacidification treatment on the flue gas delivered by the subsequent heat exchanger (9); The flue gas deoxidation device (16) is connected to the deoxidation device (15) via a conveying pipeline, and the flue gas deoxidation device (16) is used to deoxidize the flue gas after deoxidation treatment by the deoxidation device (15).