Dry-type furnace flue gas purification and waste heat recovery integrated device for co-processing multiple pollutants

Abstract

The utility model discloses a dry-type furnace flue gas purification and waste heat recovery integrated device for co-processing various pollutants, and relates to the field of flue gas recovery. A high-temperature heat exchanger, an air pre-heater, a high-temperature energy saver, a baking soda deacidification device, a dust and nitrate integrated purifier, a low-temperature energy saver, an activated carbon adsorption tower, an induced draft fan and an external smoke exhaust air pipe are sequentially arranged in the smoke flowing direction. The high-temperature heat exchanger and the baking soda deacidification process inlet flue are both connected with a feeding device, a ceramic fiber filter pipe is arranged in the dust and nitrate integrated purifier, an outlet flue is connected with a low-temperature energy saver, and redundant deacidification agents and secondary ash are pneumatically conveyed through a compressed air pipeline at the bottom. According to the device, efficient denitration and deacidification are achieved, dust particles, dioxin and heavy metal are removed, meanwhile, a waste heat recovery system recovers heat energy in a multi-section mode, all reactions are conducted at the proper temperature, secondary pollution is avoided, corrosion to system equipment is reduced, and the purposes of energy conservation and emission reduction are achieved on the whole.

Description

Technical Field

[0001] The utility model relates to the field of flue gas recovery, and in particular to a dry kiln flue gas purification and waste heat recovery integrated device for collaboratively treating multiple pollutants. Background Art

[0002] The flue gas generated by high-temperature combustion of solid waste in kilns may contain a variety of pollutants, mainly solid particulate matter generated during the combustion process: including dust and granular matter; gaseous pollutants generated during the combustion process: sulfur dioxide (SO2), nitrogen oxides (NOx) and hydrogen chloride (HCl); heavy metals: metal elements in the combustion waste, such as mercury, lead, cadmium, etc., may be discharged into the flue gas in gaseous or particulate form; at the same time, dioxins may be produced during the combustion process. Therefore, in order to prevent secondary pollution to the environment caused by the incineration process, it is necessary to purify the high-temperature flue gas generated by the incineration of solid waste.

[0003] Conventional treatment technologies for NOx in high-temperature flue gas are denitrification treatment, namely SNCR and SCR. Compared with SNCR, SCR requires the action of a catalyst and has a higher denitrification rate, but it has stricter requirements on environmental conditions such as flue gas temperature and oxygen content, and requires higher operating costs. SNCR is suitable for the treatment of some industrial flue gases with higher temperatures and higher oxygen content, but has relatively loose requirements on operating conditions, does not require the action of a catalyst, and has lower operating costs. In the treatment of high-temperature flue gas in kilns, SCR technology has certain advantages over SNCR.

[0004] For other acidic gases such as SOx, HCl and HF, conventional treatment technologies are wet deacidification and dry deacidification. Compared with wet deacidification, dry deacidification does not produce wastewater, does not cause secondary pollution, has low operating costs, and is suitable for the treatment of some high-temperature, high-ash flue gases.

[0005] The disposal methods of dioxins in solid waste mainly include high temperature disposal, biodegradation, chemical removal and low temperature pyrolysis. At present, developed countries mainly use the method of "stabilization solidification + landfill" to dispose of incineration fly ash. It is impossible to effectively detect dioxins in real time online at home and abroad, resulting in the inability to control emissions normally, which has certain limitations. Dry kiln flue gas purification technology uses high temperature environment to completely destroy dioxins in fly ash, and controls the temperature between 1300 and 1500℃. The removal rate of dioxins in solid waste can reach 98%. The high-temperature flue gas at 1200-1300℃ is rapidly cooled to 500℃ through the high-temperature heat exchanger in the waste heat boiler, which can effectively inhibit the secondary synthesis of dioxins. Finally, the possible residual and low-concentration dioxins are removed through the activated carbon adsorption tower to ensure that the dioxin content of the exhaust flue gas meets the standard.

[0006] In summary, conventional high-temperature flue gas purification treatment adopts the process of "denitrification + dust removal + deacidification + removal of dioxins and heavy metals". The process is relatively long, and the wet deacidification process will produce more wastewater and "white smoke". In view of the above situation, this patent provides a dry denitrification and dust removal + deacidification synergistic purification measure, using an activated carbon adsorption tower to remove residual dioxins and heavy metals, simplifying the process; at the same time, it adopts waste heat multi-stage recovery technology to recover heat energy, and allows the denitrification and deacidification and activated carbon adsorption processes to be carried out at a suitable reaction temperature to improve the removal efficiency. Utility Model Content

[0007] The purpose of the utility model is to overcome the shortcomings of the prior art and to provide an integrated device for dry kiln flue gas purification and waste heat recovery for the coordinated treatment of multiple pollutants, which can not only achieve better denitrification, dust removal, deacidification, dioxin and heavy metal removal effects, but also recover heat energy in stages to reduce energy consumption.

[0008] The purpose of the utility model is to be achieved through the following technical solutions: a dry kiln flue gas purification and waste heat recovery integrated device for the coordinated treatment of multiple pollutants, including a high-temperature heat exchanger, an air preheater, a high-temperature energy saver, an integrated dust and nitrate purifier, a low-temperature energy saver and an activated carbon adsorption tower, the inlet flue of the high-temperature heat exchanger is used to pass the high-temperature flue gas discharged from the kiln for preliminary denitrification, the high-temperature heat exchanger is also connected to the denitrification agent silo through a compressed air pipeline, which is used to spray the denitrification agent into the high-temperature heat exchanger to achieve primary denitrification, the outlet flue of the high-temperature heat exchanger is connected to the air preheater and the high-temperature energy saver in sequence, and the high-temperature The energy saver is connected to the baking soda silo through a compressed air pipeline. At the same time, a primary denitrification and deacidification flue gas pipeline is set between the high-temperature energy saver and the integrated dust and nitrate purifier. Compressed air is used to spray baking soda into the high-temperature energy saver, so that the flue gas is deacidified in the primary denitrification and deacidification flue gas pipeline, and then passed into the integrated dust and nitrate purifier for secondary denitrification and dust removal treatment. The rear of the integrated dust and nitrate purifier is connected in sequence to the low-temperature energy saver and the activated carbon adsorption tower. The rear end of the activated carbon adsorption tower is connected to the induced draft fan and the external smoke exhaust duct through the tee joint of the duct, thereby guiding the clean flue gas to flow into the external smoke exhaust duct.

[0009] As a further technical solution, a ceramic fiber filter tube is installed in the integrated dust and saltpeter purifier, so that the dust in the flue gas is blocked on the surface of the filter tube due to the difference in particle size. The filtered flue gas reacts with the catalyst inside the filter tube wall during the process of passing through the filter tube wall, converting nitrogen oxides into nitrogen, thereby achieving secondary denitrification.

[0010] As a further technical solution, a baffle is arranged in front of the inlet of the integrated dust and saltpeter purifier to block large particles in the flue gas; a deacidification ash injector is arranged at the bottom of the integrated dust and saltpeter purifier to transport the accumulated dust particles and excess deacidification agent to the deacidification ash storage through a compressed air pipeline for treatment, and finally store them in ton bags; the integrated dust and saltpeter purifier is provided with an air pressure measuring gauge to maintain the internal pressure drop of the integrated dust and saltpeter purifier, and control the compressed air pipeline above the ceramic fiber filter tube through an electromagnetic valve to intermittently blow compressed air to flush out the dust particles accumulated on the surface of the filter tube.

[0011] As a further technical solution, the high-temperature heat exchanger, air preheater, high-temperature economizer and low-temperature economizer recover waste heat in the flue gas, and the gas recovered by the low-temperature economizer is introduced into the activated carbon adsorption tower to re-absorb the dioxins and heavy metals remaining in the flue gas; an expansion joint is arranged between the air duct three-way joint and the induced draft fan, and a check valve is arranged between the air duct three-way joint and the external smoke exhaust air duct.

[0012] An integrated method for dry denitration, deacidification and dust removal of kiln flue gas, using the above-mentioned integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants, comprises the following steps:

[0013] 1) The flue gas at the kiln outlet is first subjected to SNCR treatment and rapid cooling in the flue of the high-temperature heat exchanger to reduce the flue gas temperature to 500°C for preliminary denitrification;

[0014] 2) After the initial denitration, the flue gas passes through the air preheater and the high-temperature economizer to reduce the flue gas temperature to 280-300°C. Then, in the primary denitration and deacidification flue gas pipeline, the sodium-based baking soda deacidification agent reacts with the initial denitration flue gas in a solid fluidization manner to perform initial deacidification;

[0015] 3) The flue gas after preliminary denitration and deacidification is passed into the integrated dust and nitrate purifier. Under the filtering action of the ceramic fiber filter element, the nitrogen oxides are converted into nitrogen, and the dust particles are deposited or adsorbed on the outside of the filter tube, and are regularly purged and collected to achieve integrated denitration and dust removal;

[0016] 4) The flue gas after secondary denitration, dust removal and deacidification passes through the low-temperature economizer and activated carbon adsorption tower in sequence under the action of the induced draft fan. The activated carbon adsorption tower is used to adsorb residual dioxins and heavy metals, and finally clean flue gas is obtained;

[0017] 5) The clean flue gas flows into the external smoke exhaust duct under the guidance of the induced draft fan.

[0018] As a further technical solution, in step 1), the flue gas discharged from the kiln outlet is produced by incineration of solid waste / hazardous waste, municipal sludge and coal; the flue gas is passed into a high-temperature heat exchanger for rapid cooling, thereby avoiding the secondary generation of dioxins and recovering waste heat at the same time.

[0019] As a further technical solution, in the step 2), the flue gas after preliminary denitrification is first introduced into the air preheater and supplied to the kiln hot air system, and then introduced into the high-temperature economizer to reduce the flue gas temperature and cooperate with the baking soda deacidification reaction, while recovering waste heat, and the particle size of the baking soda is 800 mesh.

[0020] As a further technical solution, in step 3), the deacidifying agent and dust particles at the bottom of the integrated dust and saltpeter purifier are transported to the deacidifying ash storage for treatment through a deacidifying ash ejector using compressed air.

[0021] As a further technical solution, in step 4), the flue gas after secondary denitrification, dust removal and deacidification is first passed into a low-temperature economizer to absorb waste heat and cool the flue gas to 120°C to control the flue gas reaction temperature in the activated carbon adsorption tower.

[0022] As a further technical solution, in step 5), part of the clean flue gas is introduced back into the kiln for combustion support to reduce fuel consumption.

[0023] The beneficial effects of the utility model are:

[0024] 1. The flue gas passes through the high-temperature heat exchanger (SNCR denitrification), air preheater, high-temperature energy saver, baking soda deacidification, dust and nitrate integrated purifier, low-temperature energy saver, activated carbon adsorption tower, induced draft fan and external exhaust duct in sequence. The process system is relatively simplified and feasible, with low operation difficulty and reduced flue gas pollutant emissions. At the same time, the whole system uses high-temperature heat exchangers, air preheaters, high-temperature energy savers and low-temperature energy savers, which can recover waste heat in the system, control the temperature of denitrification, deacidification and activated carbon adsorption processes, and convert waste heat into usable heat energy for heating water or air;

[0025] 2. The integrated flue gas purification process of SNCR denitrification + baking soda deacidification and dust removal is used. The primary and secondary denitrification, deacidification and dust removal processes all adopt dry processes to eliminate the complexity and danger of flue gas washing; no water is consumed for treatment, no wastewater is generated, and the corrosion of equipment is reduced and the service life is increased. The specific surface area of ​​the catalyst in the ceramic fiber filter tube wall of the secondary denitrification and dust removal process is large, and the denitrification efficiency is high, which can reach up to 95%. Compared with the traditional flue gas treatment process, the filter tube can realize surface dust removal and internal denitrification, and realize the integration of dust removal, deacidification and denitrification, which can ultimately achieve a sufficiently high NOx removal rate, significantly reduce the dust concentration in the purified flue gas, reduce the overall resistance of the purification device, and reduce the energy consumption of the fan; the filter tube replacement method is relatively simple to ensure continuous operation and up-to-standard emissions without stopping production;

[0026] 3. The entire integrated device uses high-temperature heat exchangers, air preheaters, high-temperature economizers and low-temperature economizers to realize waste heat recovery and utilization, which are used to heat medium air and water, and are used to supply the kiln hot air system and hot water system respectively, realizing the reuse of waste heat resources; at the same time, the flue gas temperature is reduced by the waste heat recovery equipment, which not only achieves the effect of rapid cooling of high-temperature flue gas to avoid the secondary generation of dioxins, but also can control the flue gas temperature so that the denitrification, deacidification and activated carbon adsorption processes can be carried out at an appropriate temperature, achieving a better pollutant removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the utility model.

[0028] Figure 2 It is a flow chart of the utility model.

[0029] Explanation of the reference numerals: high-temperature heat exchanger 1, air preheater 2, high-temperature energy saver 3, primary denitrification and deacidification flue gas duct 4, integrated dust and nitrate purifier 5, deacidification ash ejector 6, low-temperature energy saver 7, activated carbon adsorption tower 8, air duct three-way joint 9, expansion joint 10, induced draft fan 11, check valve 12, external smoke exhaust duct 13, denitrification agent silo 14, baking soda silo 15. DETAILED DESCRIPTION

[0030] The utility model will be described in detail below with reference to the accompanying drawings:

[0031] Example: As shown in the attached Figure 1 , 2 As shown, a dry kiln flue gas purification and waste heat recovery integrated device for synergistically treating multiple pollutants includes a high-temperature heat exchanger 1, an air preheater 2, a high-temperature energy saver 3, a primary denitrification and deacidification flue gas duct 4, an integrated dust and nitrate purifier 5, a deacidification ash ejector 6, a low-temperature energy saver 7, an activated carbon adsorption tower 8, an air duct three-way joint 9, an expansion joint 10, an induced draft fan 11, a check valve 12, an external exhaust air duct 13, a denitrification agent silo 14 and a baking soda silo 15.

[0032] Reference Figure 1 The inlet flue of the high-temperature heat exchanger 1 is used to pass the high-temperature flue gas discharged from the kiln for preliminary denitration. The high-temperature heat exchanger 1 is also connected to the denitrification agent silo 14 through a compressed air pipeline, which can spray the denitrification agent (usually urea) into the high-temperature heat exchanger 1 to achieve primary denitration. The outlet flue of the high-temperature heat exchanger 1 is connected to the air preheater 2 and the high-temperature energy saver 3 in sequence. The high-temperature energy saver 3 is connected to the baking soda silo 15 through a compressed air pipeline. At the same time, a primary denitration and deacidification flue gas pipeline 4 is set between the high-temperature energy saver 3 and the integrated dust purifier 5. The baking soda silo 15 uses compressed air to spray baking soda into the high-temperature energy saver 3, so that the flue gas is deacidified in the primary denitration and deacidification flue gas pipeline 4, and then passed into the integrated dust purifier 5 for secondary denitration and dust removal. The rear of the integrated dust and saltpeter purifier 5 is connected in sequence to a low-temperature energy saver 7 and an activated carbon adsorption tower 8, and the rear end of the activated carbon adsorption tower 8 is connected to the induced draft fan 11 and the external smoke exhaust duct 13 respectively through the duct three-way joint 9, thereby guiding the clean smoke to flow into the external smoke exhaust duct 13.

[0033] Furthermore, a ceramic fiber filter tube is installed in the integrated dust and saltpeter purifier 5, so that the dust in the flue gas is blocked on the surface of the filter tube due to the difference in particle size. The filtered flue gas reacts with the catalyst inside the filter tube wall during the process of filtering, and the nitrogen oxides are converted into nitrogen (NOx→N2). The purified gas is discharged to the low-temperature economizer 7 through the induced draft fan 11 for heat recovery to achieve secondary denitrification. Preferably, a baffle is provided in front of the inlet of the integrated dust and saltpeter purifier 5 to block large particles in the flue gas. In addition, the integrated dust and saltpeter purifier 5 is also provided with an air pressure measuring meter. In order to keep the internal pressure drop of the integrated dust and saltpeter purifier 5 at a reasonable level, the compressed air pipeline above the ceramic fiber filter tube is controlled by a solenoid valve, and compressed air is intermittently purged to flush out the dust particles accumulated on the surface of the filter tube. The bottom of the integrated dust purifier is also provided with a by-product outlet, which is connected to a deacidified ash injector 6 (i.e., a deacidified ash injector 6 is arranged at the bottom of the integrated dust purifier 5). Its main function is to transport the deacidified dust particles and excess deacidifying agent to the deacidified ash storage through a compressed air pipeline for processing, and finally store them in ton bags and ton bags.

[0034] The high temperature heat exchanger 1, the air preheater 2, the high temperature economizer 3 and the low temperature economizer 7 can recover the waste heat in the flue gas, and the gas recovered by the low temperature economizer 7 is passed into the activated carbon adsorption tower 8 to reabsorb the dioxins and heavy metals remaining in the flue gas. An expansion joint 10 is provided between the air duct three-way joint 9 and the induced draft fan 11, and a check valve 12 is provided between the air duct three-way joint 9 and the external exhaust air duct 13.

[0035] like Figure 2As shown, a method for integrating dry denitration, deacidification and dust removal of kiln flue gas adopts the above-mentioned integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants, including the following steps:

[0036] 1) The flue gas at the kiln outlet is first subjected to SNCR treatment and rapid cooling treatment in the flue of the high-temperature heat exchanger 1 to reduce the flue gas temperature to 500°C for preliminary denitrification; wherein, the flue gas discharged from the kiln outlet is generated by the incineration of solid waste / hazardous waste, municipal sludge and coal; the flue gas is passed into the high-temperature heat exchanger 1 for rapid cooling treatment, thereby avoiding the secondary generation of dioxins and recovering waste heat at the same time.

[0037] 2) After the initial denitrification, the flue gas passes through the air preheater 2 and the high-temperature economizer 3 to reduce the flue gas temperature to 280-300°C. Then, in the primary denitrification and deacidification flue gas pipeline 4, the sodium-based baking soda deacidification agent reacts with the initial denitrification flue gas in a solid fluidization manner to perform initial deacidification; the flue gas after the initial denitrification is first passed into the air preheater 2 and supplied to the kiln hot air system, and then passed into the high-temperature economizer 3 to reduce the flue gas temperature and cooperate with the baking soda deacidification reaction, and at the same time, waste heat is recovered. Preferably, the particle size of the baking soda is 800 mesh.

[0038] 3) The flue gas after preliminary denitrification and deacidification is passed into the integrated dust and nitrate purifier 5. Under the filtering action of the ceramic fiber filter element, nitrogen oxides are converted into nitrogen, and dust particles are deposited or adsorbed on the outside of the filter tube. They are purged and collected regularly to achieve integrated denitrification and dust removal. The deacidifying agent and dust particles at the bottom of the integrated dust and nitrate purifier 5 are transported to the deacidification ash storage for treatment through the deacidification ash injector 6 using compressed air.

[0039] 4) The flue gas after the secondary denitrification, dust removal and deacidification passes through the low-temperature energy saver 7 and the activated carbon adsorption tower 8 in sequence under the action of the induced draft fan 11, and the activated carbon adsorption tower 8 is used to adsorb residual dioxins and heavy metals to finally obtain clean flue gas; since the flue gas after the secondary denitrification, dust removal and deacidification is first passed into the low-temperature energy saver 7, the waste heat is absorbed to cool the flue gas to 120°C, and the reaction temperature of the flue gas in the activated carbon adsorption tower 8 can be effectively controlled.

[0040] 5) The clean flue gas flows into the external exhaust duct 13 under the guidance of the induced draft fan 11. In addition, part of the clean flue gas can be introduced back into the kiln for combustion support, thereby reducing fuel consumption.

[0041] This embodiment provides an integrated device for dry kiln flue gas purification and waste heat recovery for the coordinated treatment of multiple pollutants. The device includes a high-temperature heat exchanger (SNCR denitrification) 1, an air preheater 2, a high-temperature energy saver 3, a dust and nitrate integrated purifier 5, a low-temperature energy saver 7, an activated carbon adsorption tower 8, an induced draft fan 11 and an external exhaust duct 13 along the flow direction of the high-temperature kiln flue gas. The SNCR denitrification process is carried out in the high-temperature heat exchanger 1, which is connected to a urea hopper and a feeding device (i.e., a denitrification agent silo 14), and the high-temperature flue gas passes through the high-temperature heat exchanger 1 to rapidly cool the flue gas temperature to 500°C to avoid secondary synthesis of dioxins. The flue gas after primary denitrification is discharged from the outlet flue of the high-temperature heat exchanger 1 to the air preheater 2 and then to the high-temperature energy saver 3, whose outlet flue is connected to a baking soda hopper and a feeding device (i.e., a baking soda silo 15). The primary denitrification flue gas is recovered through the air preheater 2 and the high-temperature energy saver 3 for heat energy recovery, reducing the flue gas temperature to a reasonable range for the baking soda deacidification reaction. Then, a deacidification reaction is carried out with a baking soda deacidifying agent in the pipeline from the high-temperature energy saver 3 to the integrated dust purifier 5 (i.e., the primary denitration and deacidification flue gas pipeline 4), and finally a primary denitration and deacidification flue gas is obtained. A ceramic fiber filter element is used inside the integrated dust purifier 5 for secondary denitration and dust removal. A deacidification ash injector 6 is installed at the bottom of the integrated dust purifier 5, which can transport excess deacidification agent and secondary ash to the deacidification ash warehouse through compressed air. The activated carbon adsorption tower 8 is mainly used to adsorb dioxins and heavy metals that may remain in the flue gas. The discharged clean flue gas passes through the air duct three-way joint 9 to return part of the flue gas to the kiln for secondary combustion. The remaining clean flue gas is prevented from reflux by the induced draft fan 11 and the check valve 12, and finally flows into the external exhaust air duct 13.

[0042] This embodiment provides a dry furnace flue gas purification integrated device. The whole system process is simple and the operation difficulty is low. It reduces the flow resistance of flue gas, intercepts dust, and reduces secondary pollution. At the same time, the whole system uses the waste heat recovery system to control the flue gas temperature in sections to reduce energy consumption. The first-level denitrification and deacidification adopts SNCR denitrification and baking soda deacidification to neutralize sulfur dioxide (SO2), hydrogen chloride (HCl) and nitrogen oxides (NO x ) and other acidic gases, improve the flue gas purification effect and reduce the flue gas temperature. The secondary denitrification and dust removal uses a denitrification ceramic fiber filter tube with a high-efficiency catalyst, which can ultimately achieve a sufficiently high NO x The removal rate can significantly reduce the dust concentration in the purified flue gas, reduce the overall resistance of the purification device, and reduce the energy consumption of the fan.

[0043] In this embodiment, the urea feeding device includes a urea powder storage bin (denitrifier silo 14), which is set with one discharge port and has uniform urea particles. The feeding amount of urea entering the flue is controlled by a solenoid valve, and compressed air is used as power to transport it to the inlet flue of the high-temperature heat exchanger 1. At high temperature, urea reacts with nitrogen oxides in the flue gas to generate nitrogen and water. The main reaction equation is as follows:

[0044] 4NH3+4NO+O2=4N2+6H2O.

[0045] In this embodiment, a baking soda powder feeding device storage bin (baking soda silo 15) is set with one discharge port, and the feeding amount of baking soda is controlled by a hopper feeder through an electromagnetic valve, and is pneumatically transported to the outlet flue duct of the high-temperature economizer 3 by compressed air, and reacts with the flue gas after the primary denitrification treatment to perform deacidification treatment.

[0046] In this embodiment, the added sodium-based baking soda deacidifying agent comes into contact with the high-temperature flue gas discharged from the kiln, and is decomposed into Na2CO3 with smaller fineness, larger specific surface area and higher activity in the hot flue gas. SO in the flue gas discharged at the tail end of the high-temperature economizer X , HCl and baking soda deacidification agent are fully mixed and reacted. The main reaction formula is as follows:

[0047] 2NaHCO3+SO2=Na2SO3+2CO2+H2O;

[0048] 2NaHCO3+SO3=Na2SO4+2CO2+H2O;

[0049] NaHCO3+HCl=NaCl+CO2+H2O;

[0050] Na2CO3+SO2=Na2SO3+CO2;

[0051] Na2CO3+SO3=Na2SO4+CO2;

[0052] Na2SO3+1 / 2O2=Na2SO4.

[0053] In this embodiment, the primary denitrification and deacidification flue gas is discharged from the outlet of the high-temperature economizer 3. The flue gas temperature generated by the combustion of solid waste / hazardous waste in the kiln is 1200-1300°C, which is cooled to 500°C by the high-temperature heat exchanger, and then cooled to 280-300°C by the air preheater 2 and the high-temperature economizer 3.

[0054] In this embodiment, the secondary denitrification and deacidification flue gas passing through the integrated dust and salt purifier 5 is transported from the upper purified flue gas outlet through the flue to the flue gas inlet of the low-temperature energy saver 7. The secondary denitrification and deacidification flue gas is cooled to 120°C by the low-temperature energy saver.

[0055] In this embodiment, the low-temperature economizer 6 is connected to the activated carbon adsorption tower device 7 through a pipeline. The adsorption efficiency of dioxins is relatively high at the flue gas temperature, and dioxins and heavy metals that may remain in the flue gas can be removed to ensure that the flue gas meets the emission standards.

[0056] In this embodiment, the purified flue gas is discharged from the external exhaust duct 13 under the action of the induced draft fan 11.

[0057] Combined with the above-mentioned dry furnace flue gas purification and waste heat recovery integrated device for synergistic treatment of multiple pollutants, and tested on site, the specific treatment results are as follows:

[0058] After SNCR denitrification + baking soda deacidification + ceramic fiber filter tube deacidification and dust removal + activated carbon adsorption, the flue gas discharged to the external exhaust duct 13 was found to have a dust emission of ≤20mg / m 3 , SO2 emission ≤80mg / m 3 , the removal rate is 90-96%, NO x ≤100mg / m 3 HCl≤20mg / m 3 HCl removal rate is 90-98%, dioxin content is <0.1ng TEQ / Nm 3 The emission data are shown in Table 1 below, which fully meet the corresponding atmospheric emission standards of GB 18485-2014 Municipal Waste Incineration Pollution Control Standard.

[0059] Table 1 Flue gas emission comparison table Unit: mg / m 3 , except dioxins

[0060]

[0061] It is understandable that, for those skilled in the art, any equivalent replacement or change to the technical solution and the concept of the utility model should fall within the protection scope of the claims attached to the utility model.

Claims

1. An integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants, characterized in that: The invention comprises a high-temperature heat exchanger (1), an air preheater (2), a high-temperature energy saver (3), an integrated dust and nitrate purifier (5), a low-temperature energy saver (7) and an activated carbon adsorption tower (8), wherein the inlet flue of the high-temperature heat exchanger (1) is used to introduce the high-temperature flue gas discharged from the kiln for preliminary denitration, the high-temperature heat exchanger (1) is also connected to a denitrification agent silo (14) through a compressed air pipeline, and is used to spray the denitrification agent into the high-temperature heat exchanger (1) to achieve primary denitration, the outlet flue of the high-temperature heat exchanger (1) is connected to the air preheater (2) and the high-temperature energy saver (3) in sequence, the high-temperature energy saver (3) is connected to a baking soda silo (15) through a compressed air pipeline, and at the same time, the high-temperature A primary denitration and deacidification flue gas pipeline (4) is arranged between the high-temperature energy saver (3) and the integrated dust and nitrate purifier (5). Compressed air is used to spray baking soda into the high-temperature energy saver (3), so that the flue gas undergoes a primary denitration and deacidification treatment in the primary denitration and deacidification flue gas pipeline (4), and then passes into the integrated dust and nitrate purifier (5) for secondary denitration and dust removal treatment. The integrated dust and nitrate purifier (5) is connected to a low-temperature energy saver (7) and an activated carbon adsorption tower (8) in sequence at the rear. The rear end of the activated carbon adsorption tower (8) is connected to an induced draft fan (11) and an external smoke exhaust duct (13) respectively through a duct three-way joint (9), thereby guiding the clean smoke to flow into the external smoke exhaust duct (13).

2. The integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants according to claim 1 is characterized in that: A ceramic fiber filter tube is installed in the integrated dust and saltpeter purifier (5), so that the dust in the flue gas is blocked on the surface of the filter tube due to the difference in particle size. The filtered flue gas reacts with the catalyst inside the filter tube during the process of passing through the filter tube wall, converting nitrogen oxides into nitrogen, thereby achieving secondary denitrification.

3. The integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants according to claim 2 is characterized in that: A baffle is provided in front of the inlet of the integrated dust purifier (5) for blocking large particles in the flue gas; a deacidification ash injector (6) is provided at the bottom of the integrated dust purifier (5) for transporting the accumulated dust particles and excess deacidification agent to the deacidification ash storage for treatment through a compressed air pipeline, and finally storing them in ton bags; the integrated dust purifier (5) is provided with an air pressure measuring meter for maintaining the internal pressure drop of the integrated dust purifier (5), and controlling the compressed air pipeline above the ceramic fiber filter tube through an electromagnetic valve to intermittently perform compressed air blowing to flush away the dust particles accumulated on the surface of the filter tube.

4. The integrated device for dry kiln flue gas purification and waste heat recovery for collaborative treatment of multiple pollutants according to claim 1 is characterized in that: The high-temperature heat exchanger (1), air preheater (2), high-temperature economizer (3) and low-temperature economizer (7) recover waste heat in the flue gas, and the gas recovered by the low-temperature economizer (7) is introduced into the activated carbon adsorption tower (8) to reabsorb dioxins and heavy metals remaining in the flue gas; an expansion joint (10) is provided between the air duct three-way joint (9) and the induced draft fan (11), and a check valve (12) is provided between the air duct three-way joint (9) and the external smoke exhaust air duct (13).

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