CN117085482A

CN117085482A - Novel cremation machine tail gas wet treatment process method and device

Info

Publication number: CN117085482A
Application number: CN202311255844.6A
Authority: CN
Inventors: 仝明; 陈昕; 亢若宇; 项吕婷; 高红威; 任生先; 陈煜�; 潘雨艳
Original assignee: Weifeng Clean Technology Shanghai Co ltd
Current assignee: Weifeng Clean Technology Shanghai Co ltd
Priority date: 2023-09-26
Filing date: 2023-09-26
Publication date: 2023-11-21

Abstract

The invention provides aA novel cremation machine tail gas wet treatment process method and device comprise the following steps: (1) Incinerating remains in a main combustion chamber of the cremator, spraying atomized urea solution into a secondary combustion chamber for pyrolysis, and performing SNCR denitration reaction while inhibiting the generation of dioxin; (2) The incinerated high-temperature flue gas sequentially passes through a sludge drying section, a urea solution pyrolyzer, a cyclone dust collector and a GGH heat exchanger to be cooled step by step and dedusted; (3) The high-temperature flue gas is introduced into an integrated tail gas purification device and is subjected to two-stage washing and purification treatment of turbulent flushing reverse spray quenching washing and Venturi washing in sequence; (4) And (3) heating the low-temperature purified flue gas after the integrated purification treatment by using a GGH heat exchanger, introducing the low-temperature purified flue gas into a catalytic reduction reactor, and pumping the low-temperature purified flue gas into a chimney for emission by using a draught fan after reaction. The invention has the capability of removing multi-component smoke pollutants, and can synchronously and efficiently remove smoke dust and SO ₂ 、SO ₃ And pollutants such as HCl, nitrogen oxides, dioxin, heavy metals and the like, and realizes zero discharge of sewage, and the performance is stable and reliable.

Description

Novel cremation machine tail gas wet treatment process method and device

Technical Field

The invention belongs to the technical field of cremation machine tail gas treatment, and particularly relates to a novel cremation machine tail gas wet treatment process method and device.

Background

Along with the gradual expansion of the aging population of China, the cremation task of cremation machines of funeral and interment is increased day by day, and the cremation rate is improved year by year. In the operation process of the cremator, the cremation process is realized through the combustion of a cremator, waste gas containing pollutants is generated during the combustion and discharged into the atmosphere, and the harmful substances in the tail gas are more than 10, and mainly comprise persistent organic pollutants such as particulate matters, sulfur dioxide, hydrogen chloride, heavy metals (mercury), dioxin and the like. And because of the characteristics of funeral industry, the height of the chimney is generally low, and atmospheric pollutants diffuse near the ground, so that certain harm can be caused to nearby residents and the environment.

In the cremator incineration process of remains, combustible species are complex, including remains, coffins and the like. Cremation is a process of feeding remains and burial products into a hearth at one time to burn at high temperature until all combustible components are completely burned out. Because each remains component has difference, and the random burial product has complexity, diversity and non-uniformity, the remains cremation process is a discontinuous intermittent process. In addition, the fuel supply is continuously regulated in the cremation process, the furnace door is required to be opened and closed for multiple times, the fluctuation of combustion conditions in the furnace is easy to be caused, the content of pollutants in the generated flue gas is also suddenly high and suddenly low, the phenomena of deflagration and incomplete combustion exist, and the phenomenon of black smoke can occur in a chimney occasionally. Therefore, the problems of exceeding pollutant emission, poor reliability, low automation degree and the like exist in the actual operation of the cremator.

At present, various schemes are configured for the purification system of the incinerator flue gas, and the scheme is mainly characterized by different combinations of a deacidification system and a dust removal system, namely, a combination mode of acid gas absorption, dust removal, active carbon/active coke adsorption and the like is generally selected. The wet flue gas deacidification and dedusting combined technology, the semi-dry flue gas deacidification and dedusting combined technology, the dry flue gas deacidification and dedusting combined technology and the like are included, wherein the removal effect of the wet flue gas deacidification is good, the deacidification rate can reach more than 98%, and the consumption of the absorbent is small. The deacidification part generally comprises alkali liquor preparation, storage and conveying equipment, cooling washing tower equipment, washing sewage post-treatment equipment and the like. Most of the smoke pollutants enter washing slurry after washing, and are discharged after a series of sewage treatment steps such as filtering and stabilizing.

The prior art CN104406184A discloses a cremation machine tail gas purifying treatment device by utilizing wet deacidification, which comprises a flue gas cooler, a spiral dust removal adsorber, an alkali liquor desulfurization system, a steam-water separator, a cloth bag dust removal system and a smoke exhaust system which are sequentially arranged; the flue gas cooler exchanges heat with air through the heat radiating fins on the outer walls of the smoke inlet pipe, the cooling pipe and the smoke return pipe, and the flue gas is cooled to 160 ℃ or lower; the spiral dust-removing adsorber comprises a spiral separator and an active carbon box, and is used for purifying the flue gas through dust removal and adsorption; the alkali liquor desulfurization system comprises an alkali liquor spray tower, and an alkali liquor atomization spray nozzle is used for atomizing an alkali solution and fully contacting with flue gas so as to achieve the purpose of desulfurization and acid removal; the steam-water separator separates moisture in the flue gas, so that the flue gas entering a subsequent cloth bag device is ensured to be dried; the flue gas is subjected to ultra-micro filtration by a cloth bag device to remove tiny dust particles, and finally is discharged through a chimney under the action of a draught fan. CN102755805a discloses a flue gas purifying and dedusting system of an environment-friendly cremator by wet deacidification, which comprises a secondary flue gas combustion chamber, a heat exchanger, a desulfurization and dedusting tower, an anion high-voltage electrostatic dust catcher, an active carbon dust absorption tower, a fan and a chimney, wherein flue gas discharged by the secondary combustion chamber at a temperature above 1000 ℃ is quenched by the heat exchanger and cooled to a temperature below 250 ℃, deacidified and dedusted by the desulfurization and dedusting tower, cooled to normal temperature, and then subjected to high-voltage electrostatic dust removal and cyclone active carbon dust absorption in sequence and then discharged by the chimney; the flue gas entering the desulfurization and dust removal tower is directly blown into the tower bottom effusion through a flue gas pipe, overflows upwards after being washed, and contacts with the spray liquid through the guide plate layer and the ball milling layer in sequence, so that desulfurization and dust removal are realized. CN116025915a discloses a flue gas desulfurization and deacidification device for cremation machine by wet deacidification, which comprises a base, an air inlet pipe, a neutralization mechanism for desulfurizing and deacidifying flue gas and a separation mechanism for reducing harmful particles, wherein the flue gas generated by cremation machine flows into a water tank of the neutralization mechanism to contact with water through the air inlet pipe, and meanwhile, alkaline solution in a liquid storage tank is sprayed into the water tank through a spray pipe, so that the alkaline solution contacts with the flue gas, and deacidification treatment is carried out on the flue gas; the deacidified flue gas enters the separating mechanism and is discharged after being heated and filtered.

However, in the wet flue gas treatment process in the prior art, the problems of subsequent sewage discharge, treatment and the like exist due to alkali liquor spraying or washing; in addition, the treatment of pollutants in the cremation machine tail gas in the prior art is relatively single, for example, the process application aiming at denitration is fresh, and the tail gas is difficult to comprehensively reach the standard and be discharged. In addition, the temperature of the flue gas treated by the wet process is reduced below the dew point, so that the phenomenon of white smoke is formed at the outlet of the chimney, and bad landscapes are easy to cause. Therefore, it is very necessary to provide a novel cremation machine tail gas wet treatment process and a device thereof.

Disclosure of Invention

In order to solve the defects in the prior art, the invention providesProvides a novel cremation machine tail gas wet treatment process method and a device thereof. The invention has short process flow, zero sewage discharge, capability of removing multi-component smoke pollutants, and synchronous and efficient removal of smoke dust and SO ₂ 、SO ₃ The system is simple and reliable, has stable performance, and has low investment, running cost and energy consumption.

The first object of the invention is to provide a novel cremation machine tail gas wet treatment process method, which mainly comprises the following steps:

(1) Burning stage of cremator: the remains are incinerated in a main combustion chamber of the cremator, the urea solution is atomized by compressed air and then sprayed into a hearth of the cremator through a urea spray gun of a secondary combustion chamber, ammonia is generated by pyrolysis to inhibit the generation of dioxin, and simultaneously SNCR denitration reaction is carried out;

(2) Stage-by-stage cooling and dust removal: the incinerated high-temperature flue gas sequentially passes through a sludge drying section, a urea solution pyrolyzer, a cyclone dust collector and a GGH heat exchanger to be cooled step by step and primarily dedusted, and is respectively contacted with dust and flue gas in the drying slurry in sequence with the cooled dust-containing slurry from the integrated tail gas purifying device to be cooled, the atomized urea solution is pyrolyzed, cyclone separation comprises dried dust particles, and the low-temperature purified flue gas discharged by the integrated tail gas purifying device is subjected to heat exchange and cooling;

(3) An integrated tail gas purification stage: introducing the high-temperature flue gas subjected to gradual cooling and dust removal into an integrated tail gas purification device, and sequentially carrying out two-stage washing and purification of turbulent flushing reverse spray quenching washing and venturi washing, and synchronously carrying out high-efficiency quenching, dust removal, desulfurization and deacidification and heavy metal removal;

(4) And (3) a heating catalytic reaction stage: and after the temperature of the low-temperature purified flue gas after the integrated tail gas purification is increased through the GGH heat exchanger, introducing the low-temperature purified flue gas into a catalytic reduction reactor for SCR denitration reaction and decomposing dioxin and organic pollutants VOCs, and pumping the purified flue gas after the reaction into a chimney by an induced draft fan for emission.

The invention is further arranged that the oxygen content in the hearth of the cremator in the step (1) is controlled to be 4% -6%, the pressure in the hearth is controlled to be minus 50 to minus 10Pa under the micro negative pressure condition, the air distribution of the main combustion chamber and the secondary combustion chamber is automatically controlled through efficient oxygen control combustion, the main combustion chamber is ensured to burn fully under the negative pressure state, the secondary combustion chamber is further combusted to reduce the carbon monoxide and dioxin content in the flue gas, the cremator is fully combusted, and the generation amount of pollutants is reduced.

Preferably, the pressure in the hearth is controlled at a micro negative pressure of-20 Pa to-10 Pa.

The invention is further arranged that the temperature in the hearth of the cremator in the step (1) is within the range of 850-1000 ℃, the residence time of the combusted flue gas in the secondary combustion chamber in the cremator is not less than 2 seconds, excellent reaction conditions are provided for the SNCR denitration process, and meanwhile, the generation of organic pollutants VOCs and dioxin is reduced.

The invention is further arranged that the temperature of the high-temperature flue gas leaving the cremation furnace for incineration in the step (2) is 850+/-20 ℃, the cooled dust-containing slurry enters the sludge drying section, the cooled dust-containing slurry is atomized by compressed air and sprayed into the sludge drying section through a dust-containing slurry spray gun, the high-temperature flue gas is in contact, collision and mixing with the atomized dust-containing slurry, the smoke dust in the dust-containing slurry is dried by utilizing the heat energy of the high-temperature flue gas to generate solid particles, the high-temperature flue gas realizes primary cooling, and the temperature of the high-temperature flue gas leaving the sludge drying section is reduced to 670+/-20 ℃.

The invention is further arranged that the high-temperature flue gas leaving the sludge drying section in the step (2) enters the urea solution pyrolyzer, the urea solution is atomized and sent into the urea solution pyrolyzer by using compressed air to exchange heat with the high-temperature flue gas in a partition wall type mode, the atomized urea solution is decomposed into gas ammonia by using the heat energy of the high-temperature flue gas, and the gas ammonia is sent into a subsequent catalytic reduction reactor to be used as a denitration reducing agent to participate in SCR reaction, and dioxin is removed.

The invention is further arranged that the high-temperature flue gas leaving the urea solution pyrolyzer in the step (2) enters the cyclone dust collector tangentially, and the flue gas is removed and comprises smoke dust after slurry drying and is collected in an ash bucket at the bottom end of the cyclone dust collector.

The invention is further arranged that the temperature of the high-temperature flue gas leaving the cyclone dust collector in the step (2) is 660+/-20 ℃, the high-temperature flue gas enters the GGH heat exchanger to exchange gas with the low-temperature purified flue gas discharged from the integrated tail gas purifying device, the temperature of the high-temperature flue gas after GGH heat exchange is reduced to about 500+/-20 ℃, the requirement of the inlet flue gas temperature of the integrated tail gas purifying device is met, and then the high-temperature flue gas is sent into the integrated tail gas purifying device.

The invention is further arranged that the alkaline solution with the concentration of 10-30% prepared in the step (3) is sent to a slurry pool at the lower part of the integrated tail gas purifying device; and the slurry circulating pump pumps out the slurry from the slurry pool, sends the slurry into the slurry heat exchanger for cooling and then sends the slurry to a back spray nozzle of a turbulent flow back spray section in the integrated tail gas purifying device and a spray nozzle above a venturi scrubber of the main tower, so as to provide slurry for two-stage flue gas washing.

The invention is further arranged that the high-temperature flue gas passing through the GGH heat exchanger in the step (3) enters the turbulent flow reverse spraying section of the integrated tail gas purification device from top to bottom, the cooling slurry is sprayed out of the liquid upwards by the reverse spraying nozzle, the cooling slurry is in strong turbulent flow contact with the downward flowing high-temperature flue gas, and the effects of particle trapping, heavy metal removal, reaction absorption desulfurization deacidification, gas quenching cooling and the like are generated, so that the gas washing purification treatment effect is achieved.

The invention is further arranged that in the step (3), the high-temperature flue gas entering the integrated tail gas purifying device at 500+/-20 ℃ is quenched and cooled to below 80 ℃ in the turbulent reverse spraying section for less than or equal to 1 second so as to inhibit the regeneration of dioxin.

The invention is further arranged that the high-temperature flue gas in the step (3) enters the main tower of the integrated tail gas purification device after being subjected to turbulent jet and reverse jet washing, flows through a venturi scrubber consisting of a plurality of venturi tubes in the main tower from bottom to top, and fierce collision and condensation occur between fine dust particles in the flue gas and liquid drops or fine dust particles through the shrinkage tube and the venturi tube of the venturi tubes; then the dust-containing liquid drops with larger particle size are quickly condensed into dust-containing liquid drops through a diffusion pipe of the venturi tube, and then the cooling slurry sprayed out through a spray nozzle above the venturi scrubber is trapped.

The invention is further arranged that the smoke after being subjected to turbulent reverse jet quenching washing and venturi washing and secondary washing purification in the step (3) is discharged out of the integrated tail gas purifying device after the water mist carried by the smoke is removed by a baffle plate demister arranged at the upper part of the main tower; and the cooling slurry after the secondary washing and purification is respectively contacted with the flue gas to form dust-containing slurry with different concentrations, and finally, the dust-containing slurry is converged into a slurry tank of the integrated tail gas purification device, slurry circulation is formed in the integrated tail gas purification device through the action of a slurry circulating pump and a slurry heat exchanger, the pH value of the circulating slurry is controlled to be 6-9, preferably the pH value is controlled to be 6.5-7.5, so that the desulfurization and deacidification efficiency is ensured, and fresh alkali solution is continuously or intermittently supplemented into the slurry tank according to the consumption of alkaline slurry.

The invention is further arranged to regularly or irregularly wash the baffle mist eliminator through the mist eliminator water flushing nozzle arranged above or below the baffle mist eliminator according to the pressure difference change of the baffle mist eliminator, elute water mist and fine particles attached to the surface of the mist eliminator, and simultaneously ensure the liquid level of the slurry pond and reduce the concentration of secondary washing slurry.

The invention is further arranged that in the step (4), the temperature of the low-temperature purified flue gas leaving the integrated tail gas purification device is 60+/-20 ℃, the low-temperature purified flue gas enters the GGH heat exchanger to exchange heat with the high-temperature flue gas, and the temperature is raised to be more than 160 ℃ so as to ensure the reaction temperature in the subsequent catalytic reduction reactor.

The invention is further arranged that in the step (4), after the purified flue gas entering the catalytic reduction reactor is uniformly distributed by air flow, the residual nitrogen oxides in the purified flue gas are further converted into nitrogen by utilizing the gas ammonia provided by the urea solution pyrolyzer under the action of a low-temperature sulfur-resistant molybdenum vanadium titanium catalyst in the reactor; and simultaneously, the dioxin and organic pollutants VOCs in the purified flue gas are oxidized and decomposed, and the nitrogen oxides, the dioxin and the organic pollutants VOCs are removed simultaneously in a high-efficiency manner through the catalytic reaction. The reaction temperature in the catalytic reduction reactor is 160-220 ℃, preferably 180-200 ℃.

The invention further provides that in the step (4), the low-temperature purified flue gas after the integrated tail gas purification is further purified by an adsorption reactor and then enters the GGH heat exchanger to exchange heat with the high-temperature flue gas. The adsorption reactors are arranged in parallel, one is provided with one adsorption reactor, and when one adsorption reactor works, the other adsorption reactor is desorbed and regenerated. Special filter materials or activated carbon/coke are arranged in the adsorption reactor and are used as adsorption media. The filter material is porous and granular, and pollutants in the flue gas are absorbed and adsorbed by the filter material and chemically react (oxidize) with the filter material by a chemical adsorption principle to generate harmless solids which are left in the filter material, and the special filter material or the activated carbon/coke is replaced periodically or irregularly according to the use condition.

The invention is further provided that in the step (4), a circulating fan and a regeneration air preheater are also arranged for heat preservation of the catalytic reduction reactor and regeneration of the adsorption medium in the adsorption reactor, the circulating fan pumps air and/or part of purified flue gas from the catalytic reduction reactor is preheated to 180 ℃ through the regeneration air preheater, when the cremation furnace works in daytime, the preheated air is introduced into one adsorption reactor to regenerate special filter materials or activated carbon/coke in the adsorption reactor, and the analysis gas generated after regeneration is introduced into the cremation furnace to burn and decompose pollutants in the analysis gas; when the cremator is stopped at night, the preheated gas is used as heat preservation circulating gas to be returned to the catalytic reduction reactor for cyclic heating in order to ensure the temperature required by the catalytic reduction reactor.

The invention provides a novel cremator tail gas wet treatment device, which comprises a cremator, a gradual cooling and dedusting system, an integrated tail gas purification device, a catalytic reduction reactor, an induced draft fan and a chimney, wherein:

the cremator comprises a main combustion chamber and a secondary combustion chamber which are communicated, and a burner and a plurality of air inlets are arranged on a hearth; the urea spray gun is arranged in the secondary combustion chamber, an inlet of the urea spray gun is communicated with the urea solution tank and the air compressor, and is used for atomizing the urea solution by utilizing compressed air provided by the air compressor, and spraying the atomized urea solution into a hearth of the secondary combustion chamber through the urea spray gun for pyrolysis and SNCR denitration reaction;

the step-by-step cooling and dedusting system comprises a sludge drying section, a urea solution pyrolyzer, a cyclone dust collector and a GGH heat exchanger which are sequentially connected, wherein a flue gas inlet of the sludge drying section is communicated with a flue gas outlet of the cremator, and a high-temperature flue gas outlet of the GGH heat exchanger is communicated with the integrated tail gas purification device;

the integrated tail gas purification device comprises a main tower and a turbulent jet section, the bottom end of the turbulent jet section is communicated with the main tower, the top of the turbulent jet section is an integrated tail gas purification device flue gas inlet and is communicated with a high-temperature flue gas outlet of the GGH heat exchanger, a plurality of upward jet nozzles are arranged in the integrated tail gas purification device and are used for jetting slurry upwards and coaxially and oppositely flowing with the reversely moving flue gas flow to collide, and primary turbulent jet reverse jet quenching washing is performed; the top of the main tower is an integrated tail gas purification device flue gas outlet, and the bottom of the main tower is used as a slurry pool for storing alkaline slurry; the inside of the main tower is sequentially provided with a venturi scrubber, a spray nozzle and a baffle plate demister from bottom to top, wherein the venturi scrubber and the spray nozzle are used for secondary venturi scrubbing and purification of flue gas, and the baffle plate demister is used for removing water mist carried by the flue gas and then discharging the flue gas; the slurry pool is communicated with a slurry heat exchanger through a circulating slurry pump, and a slurry outlet of the slurry heat exchanger is communicated with the reverse spray nozzle and the spray nozzle to provide cooling slurry for washing and absorbing two-stage flue gas;

The exhaust gas outlet of the integrated tail gas purification device is communicated with the low-temperature flue gas inlet of the GGH heat exchanger, and the low-temperature flue gas outlet of the GGH heat exchanger is communicated with the catalytic reduction reactor, the induced draft fan and the chimney in sequence to discharge purified flue gas.

The invention is further arranged that the side wall of the sludge drying section is provided with a plurality of dust-containing slurry spray guns, and the inlet of each dust-containing slurry spray gun is communicated with the slurry outlet of the slurry heat exchanger and the air compressor; and a urea solution inlet of the urea solution pyrolyzer is communicated with the urea solution tank and the air compressor, and an ammonia outlet of the urea solution pyrolyzer is communicated with an inlet of the catalytic reduction reactor.

The invention is further characterized in that two parallel adsorption reactors are arranged between the flue gas outlet of the integrated tail gas purification device and the low-temperature flue gas inlet of the GGH heat exchanger, the two adsorption reactors are provided with a special filter material or activated carbon/coke, and the adsorption reactors are internally provided with special filter materials or activated carbon/coke, so that the flue gas is further purified by utilizing the absorption, adsorption and chemical reaction actions of the special filter materials or activated carbon/coke; the adsorption reactor is also provided with a regeneration gas inlet and a regeneration gas outlet, and is used for introducing preheated gas to regenerate the filter material or the activated carbon/coke.

The invention is further arranged that an air flow uniform distribution device and a plurality of layers of wide-temperature catalysts are arranged in the catalytic reduction reactor, the air flow uniform distribution device comprises a diversion grid and a rectification grid and is used for ensuring uniform distribution of flue gas, the wide-temperature catalysts are preferably one to three layers, and are preferably low-temperature sulfur-resistant molybdenum vanadium-titanium catalysts, the activation temperature is more than or equal to 160 ℃, the flue gas temperature is wide in the catalyst treatment, the nitrogen oxide removal efficiency can reach more than 90% in the temperature range of 150-400 ℃, the catalyst has excellent low-temperature sulfur-resistant performance, the poisoning of sulfate and sulfite formed by SOx in the flue gas on the catalyst can be slowed down, and simultaneously dioxin and organic pollutants VOCs are adsorbed on the surface of the catalyst, and catalytic oxidation reaction occurs at the active position of the catalyst, so that the dioxin is decomposed to generate CO ₂ 、H ₂ O、HCl、H ₂ The catalyst can not only catalyze and eliminate NOx, but also remove dioxin and organic pollutants VOCs by high-efficiency oxidation.

The invention is further arranged that the outlet of the catalytic reduction reactor is communicated with a regeneration air preheater through a circulating fan, the regeneration air preheater is also communicated with the outside air, and the outlet of the regeneration air preheater is communicated with a regeneration gas inlet of the adsorption reactor and an inlet of the catalytic reduction reactor and is respectively used for regenerating special filter materials or activated carbon/coke in the adsorption reactor and preserving heat of the catalytic reduction reactor; and a regenerated gas outlet of the adsorption reactor is communicated with a burner of the cremator, and the resolved gas generated by the regeneration of the adsorption reactor is sent into the cremator for incineration treatment.

Compared with the prior art, the invention has the beneficial effects that:

(1) The invention has the advantages of short process flow, small system resistance, simple and reliable system, stable performance, low investment, running cost and energy consumption, realizes zero sewage discharge, solves the problems of single pollutant treatment and insufficient denitration and desulfurization capability in the existing cremation machine tail gas treatment technology, has the capability of efficiently removing multi-component flue gas pollutants, and can synchronously and efficiently remove smoke dust and SO ₂ 、SO ₃ The pollutants such as HCl, nitrogen oxides, dioxin, organic pollutants VOCs, heavy metals and the like are comprehensively discharged up to the standard; the emission index can be further optimized on the basis of the existing national standard by adjusting the operation parameters.

(2) The invention adopts the high-efficiency oxygen-control combustion technology, optimizes the structure and shape design of the combustion chamber, automatically controls the air distribution of the main combustion chamber and the secondary combustion chamber, controls the oxygen content of the flue gas in the cremator to be 4-6%, ensures that the main combustion chamber burns fully in a negative pressure state, and the secondary combustion chamber further burns to reduce the carbon monoxide, organic pollutants VOCs and dioxin content in the flue gas; meanwhile, a urea spray gun is arranged in the secondary combustion chamber, urea solution is sprayed into a hearth of the secondary combustion chamber to generate ammonia through pyrolysis, generation of dioxin is restrained, the residence time of flue gas is not less than 2s, SNCR denitration reaction is carried out by utilizing a proper temperature field of combustion of the cremator, and the content of nitrogen oxides in flue gas at an outlet of the cremator is reduced.

(3) The sludge drying section is arranged, dust-containing slurry in the system is atomized and sprayed into contact with high-temperature flue gas generated by incineration, the dust-containing slurry is subjected to drying treatment by utilizing the heat energy of the high-temperature flue gas, on one hand, the flue gas is initially cooled, meanwhile, the introduced dust-containing slurry can not introduce extra pollutants into the flue gas, dust and heavy metals contained in the flue gas can be removed in the contact collision process, and the dust-containing slurry is alkaline liquid for subsequent treatment, so that the high-temperature flue gas can be subjected to desulfurization and deacidification pretreatment; on the other hand, the slurry is dried to generate solid particles, so that the zero emission of the sewage of the whole system is realized, the solid content in the slurry is reduced, the abrasion of the slurry to a slurry circulating pump, a reverse spray nozzle, a spray nozzle and the like is reduced, the maintenance frequency is reduced, and the continuous and stable operation of the integrated tail gas purifying device is ensured.

(4) The urea solution pyrolyzer provided by the invention utilizes the heat energy of high-temperature flue gas to decompose urea solution into ammonia gas, and the ammonia gas is sent to the catalytic reduction reactor for SCR denitration reaction, so that the energy consumption of the system is reduced.

(5) The integrated tail gas purification device provided by the invention can be used for efficiently completing the integration of quenching of flue gas, dust removal, desulfurization and deacidification and heavy metal removal, and realizing energy conservation and synergy.

The turbulent jet reverse spray washing process utilizes the principle of impact science, and the uniquely designed non-atomized large-caliber reverse spray nozzle solves the problem that a spray head is easy to block in the traditional wet washing process, and greatly reduces the operation pressure of the spray head; and can adapt to multiple change of flue gas operating mode, purifying effect keeps good simultaneously: the gas phase material must pass through the turbulent exchange field of liquid phase, so that the change of gas quantity only makes the dynamic exchange field position move and has little influence on the removal efficiency, the turbulent contact has obvious adaptability to the change of gas phasor, and the removal rate is basically unchanged when the gas quantity in the system is changed by about 50%.

The high-temperature flue gas entering the integrated tail gas purifying device at 500+/-20 ℃ is quenched and cooled to below 80 ℃ in a turbulent flow reverse spraying section in a time of not more than 1 second so as to inhibit the regeneration of dioxin.

In the venturi washing process, the shrinkage tube, the throat and the diffusion tube of the venturi washer lead the fine dust particles to collide with the liquid drops or the fine dust particles and agglomerate strongly due to the rapid expansion and reduction of the relative flow velocity between the gas phase and the liquid phase, thereby concentrating and filtering finer dust in the flue gas and playing the roles of desulfurization and deacidification, dust removal and heavy metal removal.

(6) The GGH heat exchanger provided by the invention fully utilizes the heat energy of high-temperature flue gas generated by the system, exchanges heat with the integrated purified cooling and purifying flue gas, reduces the energy consumption of the system, and prevents the disordered emission of heat energy. And the temperature of the cooled and purified flue gas is raised, so that the optimal reaction temperature range of the subsequent catalytic reduction reactor is ensured.

(7) The two adsorption reactors arranged behind the integrated tail gas purification device alternately work, so that the service life of special filter materials or activated carbon/coke can be prolonged, the replacement frequency can be reduced, and the running cost can be reduced; meanwhile, a regeneration air preheater is arranged behind the catalytic reduction reactor, purified flue gas after catalytic reduction is sent to preheated air, heat energy of the purified flue gas is utilized, the obtained preheated gas is used as a special filter material or activated carbon/coke in one of the adsorption reactors for regeneration during the operation of the cremator in the daytime, and the preheated gas is returned to the catalytic reduction reactor for heat preservation during the shutdown of the cremator at night, so that the efficiency of denitration, dioxin removal and organic pollutant VOCs in the catalytic reactor is improved.

(8) The invention adopts cyclone dust removal, turbulent jet dust removal and Venturi washing dust removal of an integrated purification device, the total dust removal efficiency of a dust removal system is not less than 99%, and the dust emission is less than 30mg/Nm ³ The dust removal operation and maintenance cost is low.

(9) The method adopts multistage measures to eliminate dioxin in the flue gas, and comprises the steps of controlling the combustion temperature of a secondary combustion chamber, controlling urea pyrolysis in the secondary combustion chamber to ammonia to inhibit the generation of dioxin, reducing the temperature of sludge drying flue gas, reducing the temperature of GGH heat exchanger flue gas, quenching an integrated tail gas purification device, catalyzing and reducing reaction technology, special filter materials or activated carbon/pyro-oxidative decomposition reaction/adsorption, and ensuring the removal of dioxin.

(10) The external exhaust gas does not need to be discharged by flue gas reheating, the flow rate of the flue gas at the outlet of the chimney is higher, white smoke is not generated, the self-pulling force of the chimney is not influenced, the diffusion effect of the flue gas is good, the floor concentration of pollutants such as outlet dust, NOx and the like is lower, the discharge requirement is met, and the influence on the surrounding environment is small.

Drawings

FIG. 1 is a schematic structural diagram of a novel cremation machine tail gas wet treatment process flow of the present invention;

FIG. 2 is a schematic structural view of an integrated exhaust gas purifying device according to the present invention;

FIG. 3 is a process flow diagram of a novel cremation machine tail gas wet treatment process of the present invention.

Detailed Description

The technical scheme of the invention is clearly and completely described in the following by specific embodiments. It is to be understood that the described embodiments are only some, but not all, of the embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

As shown in fig. 1 and 3, the novel cremator tail gas wet treatment device comprises a cremator 1, a gradual cooling and dust removing system, an integrated tail gas purifying device 10, a catalytic reduction reactor 15, an induced draft fan 16 and a chimney 17, wherein:

the cremator 1 comprises a main combustion chamber 1-1 and a secondary combustion chamber 1-2 which are communicated, wherein a burner 1-3 and a plurality of air inlets 1-4 are respectively arranged on a hearth of the main combustion chamber 1-1 and the secondary combustion chamber 1-2, the burner 1-3 is communicated with an external fuel supply pipeline, and the air inlets 1-4 are communicated with a combustion-supporting fan 2 to respectively provide fuel and combustion-supporting air for combustion in the hearth; the two-combustion chamber 1-2 is internally provided with a urea spray gun 1-5, an inlet of the urea spray gun 1-5 is communicated with a urea solution tank 3 and an air compressor 5, compressed air provided by the air compressor 5 is utilized to atomize urea solution, the urea solution is sprayed into a hearth of the two-combustion chamber 1-2 through the urea spray gun 1-5 to be thermally decomposed and subjected to selective non-catalytic reduction (SNCR) denitration reaction, the generation of dioxin is inhibited, and the content of nitrogen oxides in the flue gas at an outlet of the cremator 1 is reduced;

the step-by-step cooling and dedusting system comprises a sludge drying section 4, a urea solution pyrolyzer 6, a cyclone dust collector 7 and a GGH heat exchanger 8 which are sequentially connected, wherein a flue gas inlet of the sludge drying section 4 is communicated with a flue gas outlet of the cremator 1, a plurality of dust-containing slurry spray guns 4-1 are arranged on the side wall of the sludge drying section 4, an inlet of each dust-containing slurry spray gun 4-1 is communicated with the integrated tail gas purification device 10 and the air compressor 5, compressed air provided by the air compressor 5 is utilized to atomize dust-containing slurry after deacidification and dedusting in the integrated tail gas purification device 10 into the sludge drying section 4, and the dust-containing slurry is contacted with high-temperature flue gas for collision and mixing, and the heat energy of the high-temperature flue gas is utilized to dry smoke dust in the dust-containing slurry; the flue gas outlet of the sludge drying section 4 is communicated with the flue gas inlet of the urea solution pyrolyzer 6, the urea solution inlet of the urea solution pyrolyzer 6 is communicated with the urea solution tank 3 and the air compressor 5, compressed air provided by the air compressor 5 is utilized to atomize the urea solution, the urea solution is sent into the urea solution pyrolyzer 6 to decompose the urea solution into ammonia gas by utilizing the heat energy of high-temperature flue gas, the ammonia gas outlet of the urea solution pyrolyzer 6 is communicated with the inlet of the catalytic reduction reactor 15, and the ammonia gas is used as a denitration reducing agent to participate in Subsequent Catalytic Reduction (SCR) reaction; the flue gas outlet of the urea solution pyrolyzer 6 is communicated with the flue gas inlet of the cyclone dust collector 7, and the bottom end of the cyclone dust collector 7 is provided with an ash bucket 8 for collecting the dust which is removed by cyclone dust collection and contains the dried slurry; the flue gas outlet of the cyclone dust collector 7 is communicated with the high-temperature flue gas inlet of the GGH heat exchanger 8, and the high-temperature flue gas and the low-temperature purified flue gas discharged by the integrated tail gas purification device 10 are subjected to gas-gas heat exchange and temperature reduction and then are sent into the integrated tail gas purification device 10.

Referring to fig. 2, the integrated tail gas purifying device 10 has the functions of quenching, dedusting, desulfurizing and deacidifying simultaneously, and comprises a main tower 10-1 and a turbulent jet reverse spraying section 10-2 with the bottom end communicated with the main tower 10-1, wherein the top of the turbulent jet reverse spraying section 10-2 is an integrated tail gas purifying device flue gas inlet 10-3 communicated with a high temperature flue gas outlet of the GGH heat exchanger 8, and a plurality of upward reverse spraying nozzles 10-4 are arranged in the integrated tail gas purifying device for spraying slurry upwards, coaxially and oppositely flowing with the reversely moving flue gas flow to collide, and performing primary turbulent jet reverse spraying quenching washing; the top of the main tower 10-1 is an integrated tail gas purification device flue gas outlet 10-5, and the bottom is used as a slurry pool for storing alkaline slurry; the inside of the main tower 10-1 is sequentially provided with a venturi scrubber 10-6, a spray nozzle 10-7 and a baffle plate demister 10-8, wherein the venturi scrubber 10-6 and the spray nozzle 10-7 are used for secondary venturi scrubbing and purification of flue gas, fine particles and water vapor in the flue gas are separated, the fine particles and the water vapor are condensed into dust-containing liquid drops with larger particle sizes through the venturi scrubber 10-6, and then are trapped by spray liquid of the spray nozzle 10-7 above, and the baffle plate demister 10-8 is used for removing the water mist carried by the flue gas and then discharging the flue gas; the slurry pool is communicated with an alkali dissolving tank 11 to provide NaOH alkali solution for the integrated tail gas purification device 10, the slurry pool is also communicated with a slurry inlet of a slurry heat exchanger 13 through a circulating slurry pump 12, the slurry is cooled through heat exchange with cooling water, a slurry outlet of the slurry heat exchanger 13 is communicated with a reverse spray nozzle 10-4 and a spray nozzle 10-7 to provide cooling slurry for two-stage flue gas washing and absorption, and a slurry outlet of the slurry heat exchanger 13 is also communicated with an inlet of a dust-containing slurry spray gun 4-1 of the sludge drying section 4 to dry smoke dust in the dust-containing slurry.

The integrated tail gas purification device is characterized in that a flue gas outlet 10-5 is communicated with a low-temperature flue gas inlet of the GGH heat exchanger 8, low-temperature purified flue gas exchanges heat with high-temperature flue gas which is not subjected to integrated tail gas purification treatment, the low-temperature flue gas outlet of the GGH heat exchanger 8 is communicated with an inlet of the catalytic reduction reactor 15, denitration and decomposition of dioxin and organic pollutants VOCs are further carried out in the catalytic reduction reactor 15, an outlet of the catalytic reduction reactor 15 is communicated with the chimney 17 through the induced draft fan 16, and the treated purified flue gas is discharged to the atmosphere outside the chimney 17.

Further, a mist eliminator water flushing nozzle 10-9 is arranged above or below the baffle mist eliminator 10-8, and the mist eliminator water flushing nozzle 10-9 is connected with external process water, and as the rising purified flue gas possibly still contains water mist and fine particles, the water mist and fine particles can adhere to the surface of the baffle mist eliminator 10-8, flushing can be performed regularly or irregularly according to the pressure difference change of the baffle mist eliminator 10-8, and meanwhile, the liquid level of a slurry pond is ensured and the concentration of secondary washing slurry is reduced.

Further, the slurry heat exchanger 13 is provided with a cooling water tower 14 in a matching way, and a water inlet and a water outlet of the cooling water tower 14 are respectively connected with a cooling water outlet and a cooling water inlet of the slurry heat exchanger 13 to provide continuous cooling medium for cooling the slurry in the slurry heat exchanger 13; the water inlet of the cooling water tower 14 is also connected with external process water to provide a water source for the cooling water tower 14.

Furthermore, two parallel adsorption reactors 18 are arranged between the flue gas outlet 10-5 of the integrated tail gas purification device and the low-temperature flue gas inlet of the GGH heat exchanger 8, the two adsorption reactors 18 are provided, special filter materials or activated carbon/coke are arranged in the adsorption reactors 18, and the adsorption effect of the special filter materials or activated carbon/coke is utilized to further purify the flue gas. The adsorption reactor 18 is also provided with a regeneration gas inlet and a regeneration gas outlet for introducing preheated gas to regenerate the special filter material or activated carbon/coke.

Further, an air flow uniformly-distributing device and a plurality of layers of wide-temperature catalysts (not shown in the figure) are arranged in the catalytic reduction reactor 15, the air flow uniformly-distributing device comprises a diversion grid and a rectification grid and is used for ensuring uniform distribution of flue gas, the wide-temperature catalysts are preferably one layer to three layers, the low-temperature sulfur-resistant molybdenum vanadium titanium catalysts are preferably selected, the activation temperature is more than or equal to 160 ℃, dioxin and organic pollutants VOCs can be almost completely decomposed into carbonic acid gas under the condition of 180-200 ℃, and the catalysts can be used for catalyzing and eliminating NOx and can also be used for efficiently oxidizing and removing the dioxin and the organic pollutants VOCs.

Further, a part of flue gas led out from the outlet of the catalytic reduction reactor 15 is communicated with the inlet of a regeneration air preheater 20 through a circulating fan 19, the regeneration air preheater 20 is also communicated with the outside air, the regeneration air preheater 20 is an electric heating preheater, purified flue gas and/or air are preheated in the regeneration air preheater 20, the outlet of the regeneration air preheater 20 is communicated with the regeneration gas inlet of the adsorption reactor 18 and the inlet of the catalytic reduction reactor 15, and the outlet of the regeneration air preheater 20 is respectively used for regenerating special filter materials or activated carbon/coke in the adsorption reactor 18 and preserving heat in the catalytic reduction reactor 15 in different periods; the regenerated gas outlet of the adsorption reactor 18 is communicated with the burner nozzles 1-3 of the cremator 1, and the analysis gas regenerated by the adsorption reactor 18 is sent into the cremator 1 for harmless burning in the regeneration time. In the heat preservation time in the catalytic reduction reactor 15, the preheated gas is circulated through a circulating fan 19 and a connecting pipe between the regenerated air preheater 20 and the inlet and the outlet of the catalytic reduction reactor 15, so as to achieve the heat preservation effect and maintain the activity of the catalyst in the catalytic reduction reactor.

The invention adopts the novel cremator tail gas wet treatment device to treat the incineration flue gas of the cremator, and aims at main pollutants: the process is respectively controlled and treated by the following aspects of acid gases such as smoke dust, sulfur dioxide, hydrogen chloride and the like, carbon monoxide, nitrogen oxides, dioxin, heavy metals and the like:

(1) The combustion working condition in the cremator is adjusted, and the generation of carbon monoxide, dioxin and organic pollutants VOCs is reduced

As the cremator 1 runs intermittently and is influenced by the variety and quantity of the burial products, the smoke quantity fluctuates greatly. The cremator 1 operates in a micro negative pressure operation mode in a pressure zone with the best operation effect, and the cremation is discharged when the negative pressure is too large and the combustion is insufficient, so that the load and difficulty of subsequent purifying equipment are greatly improved; and pollutants can be discharged to an indoor operation space by positive pressure of the hearth, so that the working environment is deteriorated, and the health of staff is damaged.

By optimizing the combustion conditions in the hearth of the cremator 1 and improving the combustion program, the combustion oxygen content of the cremator 1 is guaranteed to be 4% -6%, the temperature of the secondary combustion chamber 1-2 is guaranteed to be not lower than 850 ℃, the combustion process is guaranteed to be complete, and pollutants, particularly carbon monoxide, dioxin and organic pollutants VOCs, can be reduced.

(2) Flue gas denitration process

Denitration is performed using a combination of selective non-catalytic reduction (SNCR) + catalytic reduction (SCR) processes. The SNCR process is mainly carried out in a temperature range of 650-1000 ℃, and urea solution is sprayed into the flue gas in the furnace of the secondary combustion chamber 1-2 to reduce NOx in the flue gas and generate nitrogen and water; the SCR technology adopts the urea solution pyrolyzer 6 to exchange heat between the urea solution and the high-temperature flue gas after sludge drying, and uses the heat energy of the flue gas to decompose urea into ammonia, and the ammonia enters the catalytic reduction reactor 15 to reduce the residual nitrogen oxides in the flue gas into nitrogen under the action of a catalyst, so as to achieve the purpose of removing the nitrogen oxides.

(3) Step-by-step cooling process for flue gas

By adopting the process combination of the sludge drying section 4+urea solution pyrolyzer 6+GGH heat exchanger 8, the incineration flue gas at the outlet of the cremator is gradually cooled, and the high-temperature incineration flue gas at 850+/-20 ℃ is gradually cooled to 500+/-20 ℃.

Firstly, the sludge drying section 4 is adopted, the heat energy of the burnt high-temperature flue gas is utilized, the washed dust-containing slurry wastewater discharged from the integrated tail gas purification device 10 is sprayed and dried in the sludge drying section 4, the flue gas is directly contacted with liquid sprayed after atomization, the mass transfer speed and the heat transfer speed are higher, the sprayed liquid is rapidly vaporized to take away a large amount of heat, the first-stage cooling of the flue gas is realized, and the zero emission of sewage is realized.

And then the urea solution pyrolyzer 6 is adopted, the heat energy of the flue gas discharged by the sludge drying section 4 is utilized to decompose and gasify the urea solution, so that the second-stage cooling of the flue gas is realized, and meanwhile, the formed gas ammonia enters the subsequent catalytic reduction reactor 15 to participate in SCR (selective catalytic reduction) reaction denitration.

Finally, the GGH heat exchanger 8 is adopted, and low-temperature purified smoke discharged by the integrated tail gas purification device 10 and high-temperature smoke discharged by the cyclone dust collector 7 are used for heat exchange, so that on one hand, the third-stage cooling effect on the high-temperature smoke is achieved, and the smoke inlet requirement of the integrated tail gas purification device 10 is ensured to be met; on one hand, the temperature of the purified flue gas is raised to the activation temperature of the catalytic reduction reactor 15, so that denitration and dioxin removal and organic pollutant VOCs reaction are facilitated in the catalytic reduction reactor 15.

(4) Flue gas quenching cooling and desulfurizing deacidification process

By adopting the integrated tail gas purifying device 10, the integrated tail gas purifying treatment such as quenching cooling, desulfurization and deacidification, heavy metal removal, dust removal and the like is carried out on the flue gas by utilizing the two-stage purifying process technologies of turbulent flow reverse spray quenching washing and venturi washing.

The turbulent jet reverse jet quenching washing process adopts a non-atomized reverse jet nozzle 10-4, sprays liquid phase materials containing particles or droplets upwards, coaxially and oppositely flows and impacts with the reversely moving flue gas flow, the liquid phase uniformly spreads in a radial way under the action of different self-rotating centrifugal forces at different positions on the section, the turbulent jet reverse jet section 10-2 cylinder is sealed from the center outwards, the liquid is enabled to swirl and turn over on the microcosmic surface, the surface updating capability is improved, meanwhile, the liquid phase materials are in strong turbulent jet contact with downward flowing gas, the liquid phase energy and the gas phase energy are fully dispersed and emulsified, the dynamic exchange field of energy, mass and heat is established, and the dynamic exchange field is established. The gas is in turbulent contact with the surface of the liquid which is extremely large and updated rapidly, so that the effects of particle trapping, reaction absorption, desulfurization, deacidification, gas quenching and the like are generated, and the aim of gas purification treatment is fulfilled.

The venturi washing process adopts a venturi washer 10-6 and a spray nozzle 10-7 which are arranged at the upper part of a main tower 10-1 and are composed of a plurality of venturi tubes. When the flue gas after primary turbulent jet reverse quenching washing contains fine particles and water vapor and goes upward through the venturi scrubber 10-6, the flue gas firstly passes through the shrinkage pipe and the venturi pipe of the venturi scrubber 10-6, the relative flow velocity between the gas phase and the liquid phase in the shrinkage pipe and the venturi pipe is very high, the gas is saturated by water, and the gas film attached to the surface of dust particles is broken through, so that the dust particles are wetted by the water, and therefore, the fine dust particles and liquid drops or fine dust particles are subjected to violent collision and condensation; then in the diffusion tube of the venturi tube, along with the reduction of the air flow speed and the return of the pressure, the agglomeration effect taking dust particles as condensation nuclei occurs faster, and the dust particles are agglomerated into dust-containing liquid drops with larger particle size, and then are captured by the spray liquid at the upper end of the venturi scrubber 10-6.

(5) Heavy metal removing process for flue gas

And the sludge drying section 4 and the integrated tail gas purification device 10 are combined to remove heavy metals. And when the high-temperature flue gas is contacted with the sprayed dust-containing slurry in the sludge drying section 4 for cooling, the dust-containing slurry is sprayed and dried, so that the zero emission of sewage is realized and the heavy metals in the flue gas are removed. The heavy metals in the flue gas are removed in the integrated tail gas purification device 10 by utilizing the quenching washing process of turbulent flow reverse spray and the venturi washing process for quenching cooling, desulfurizing and deacidifying and dedusting.

(6) Flue gas dust removal process

The cyclone dust collector 7 and the integrated tail gas purification device 10 are combined to remove dust, and the turbulent flow reverse spray quenching washing and venturi washing process is utilized in the integrated tail gas purification device 10 to remove dust, so that the total dust removal efficiency of the dust removal system is not lower than 99%.

(7) Process for removing and purifying dioxin and organic pollutant VOCs

Dioxins are aromatic hydrocarbon compounds produced by connecting two benzene rings through an oxygen atom, and are a general term for two types of compounds, PCDDs and PCDFs. The dioxin catalytic purification is that under the aerobic environment, the dioxin is adsorbed on the surface of a catalyst, and catalytic oxidation reaction occurs at the active position of the catalyst, so that the dioxin is decomposed to generate CO ₂ 、H ₂ O, HCl, etc.

The process for removing and purifying dioxin and organic pollutants VOCs comprises the steps of firstly adopting a high-temperature method, and reducing the generation of dioxin and organic pollutants VOCs in a secondary combustion chamber through high temperature and residence time of not less than 2 seconds; and secondly, a catalytic method is adopted, a low-temperature sulfur-resistant molybdenum vanadium titanium wide-temperature catalyst is used in the catalytic reduction reactor 15, dioxin and organic pollutants VOCs are adsorbed on the surface of the catalyst under the conditions of 180-200 ℃ and oxygen, catalytic oxidation reaction occurs at the active position of the catalyst, and the carbonic acid gas can be almost completely decomposed without any secondary pollution. The method can remove the nitrogen oxides by high-efficiency oxidation while catalyzing.

Specifically, the invention adopts the novel cremator tail gas wet treatment device to carry out the wet treatment process on the incineration tail gas of the cremator, and is shown by referring to fig. 1-3, and mainly comprises the following steps:

first, cremation stage of cremator

The remains are sent into a main combustion chamber 1-1 of a cremator 1, and a rear chamber furnace door of the cremator 1 is closed; the method comprises the steps of feeding fuel such as natural gas ng or fuel oil into a burner 1-3, igniting remains to start incineration under the assistance of combustion air a provided by a combustion fan 2, observing the temperature rise and pressure conditions in a hearth through a temperature instrument and a pressure instrument arranged on a cremator 1, controlling the pressure in the hearth under the micro negative pressure condition of minus 50 to minus 10Pa through the variable frequency adjustment of a draught fan 16, logically interlocking the frequency of the draught fan with a main combustion chamber pressure meter, and keeping the pressure of the hearth stable under the micro negative pressure. Preferably, the pressure in the hearth is controlled at a micro negative pressure of-20 Pa to-10 Pa.

Under the normal operation condition of the cremator 1, the combustion temperature of the hearth is generally within the range of 850-1000 ℃ and is positioned in an efficient 'temperature window' of the SNCR process; and the residence time of the flue gas after combustion in the secondary combustion chamber 1-2 in the furnace exceeds 0.5 seconds, thereby providing a natural excellent reactor for the SNCR process.

The urea solution u is dissolved in the urea solution tank 3 to prepare urea solution u1 with the concentration of 5% -30% by using process water w, when the temperature in the hearth of the cremator 1 reaches 850 ℃, part of the urea solution u1 is sent to the urea spray gun 1-5 of the cremator secondary combustion chamber 1-2, compressed air a2 provided by the air compressor 5 is utilized to atomize the urea solution u1, the urea spray gun 1-5 is sprayed into the hearth of the cremator for pyrolysis to generate ammonia, and simultaneously, SNCR denitration reaction is carried out, the outlet flue gas temperature of the cremator secondary combustion chamber 1-2 is controlled to be 850+/-20 ℃, an oxygen content analyzer (not shown in the figure) is arranged in the hearth of the cremator 1, the oxygen content in the hearth of the cremator 1 is controlled to be 4% -6%, the burning time is about 50 minutes, the generation of CO is fully combusted is ensured, the residence time of the flue gas in the secondary combustion chamber 1-2 in the cremator is not less than 2 seconds, and the flue gas after the combustion is discharged out of the cremator 1 from the flue gas outlet of the cremator.

(II) stage by stage cooling and dedusting

The temperature of the incineration high-temperature flue gas g1 leaving the cremator 1 is about 850+/-20 ℃, the incineration high-temperature flue gas g1 enters a sludge drying section 4, cooled dust-containing slurry L3 from an integrated tail gas purification device 10 is sent to a dust-containing slurry spray gun 4-1 of the sludge drying section 4, compressed air a2 provided by an air compressor 5 atomizes the dust-containing slurry L3 into the sludge drying section 4, the high-temperature flue gas g1 and the atomized dust-containing slurry L3 in the sludge drying section 4 are in contact collision and are mixed, the water in the dust-containing slurry L3 is evaporated by utilizing the heat energy of the high-temperature flue gas g1, and the smoke dust in the slurry is dried to generate solid particles, so that on one hand, the primary cooling of the flue gas is realized, the temperature of the flue gas g2 at the flue gas outlet of the sludge drying section 4 is reduced to 670+/-20 ℃, and meanwhile, the introduced dust-containing slurry can not introduce additional pollutants into the flue gas, dust and heavy metals contained in the flue gas can be removed in the contact collision process, and the high-temperature flue gas can be subjected to the pretreatment of desulfurization and deacidification of the flue gas because the dust-containing slurry is the subsequent integrated tail gas purification treatment; on the other hand, for dust-containing slurry, slurry drying produces solid particles, so that the zero emission of sewage of the whole system is realized, and meanwhile, the slurry drying reduces the solid content in the slurry and reduces the abrasion of the slurry to equipment such as pumps, nozzles and the like.

The high-temperature flue gas g2 leaving the sludge drying section 4 enters a urea solution pyrolyzer 6, part of urea solution u1 from the urea solution tank 3 is atomized by compressed air a1 provided by an air compressor 5 and sent into the urea solution pyrolyzer 6, the high-temperature flue gas g2 in the urea solution pyrolyzer 6 and the urea solution u1 perform partition wall type heat exchange, the atomized urea solution u1 is decomposed into gas ammonia u2 by using the heat energy of the high-temperature flue gas g2, and the gas ammonia u2 is sent into a catalytic reduction reactor 15 to participate in SCR reaction as a denitration reducing agent, and dioxin is removed.

The high-temperature flue gas g3 leaving the urea solution pyrolyzer 6 tangentially enters a cyclone dust collector 7, and is subjected to gas-solid separation in the cyclone dust collector 7 by utilizing the difference of centrifugal force, so that smoke dust containing slurry after drying in the flue gas is removed and is collected in an ash bucket 8 arranged at the bottom end of the cyclone dust collector 7.

The temperature of the high-temperature flue gas g4 leaving the cyclone dust collector 7 is about 660+/-20 ℃, the high-temperature flue gas enters the GGH heat exchanger 8 to exchange gas with the low-temperature purified flue gas g6 discharged from the integrated tail gas purification device 10, the temperature of the high-temperature flue gas g5 subjected to GGH heat exchange is reduced to about 500+/-20 ℃, the requirement of the inlet flue gas temperature of the integrated tail gas purification device 10 is met, and the high-temperature flue gas is fed into the integrated tail gas purification device 10.

(III), an integrated tail gas purification stage

The integrated tail gas purification stage utilizes a turbulent flow reverse spray quenching washing and venturi washing two-stage purification process to remove SO in the flue gas ₂ Simultaneously, the device can synchronously and efficiently quench and cool, efficiently remove dust and SO ₃ Acid gases such as HCl and the like and heavy metal removal.

In the alkali dissolving tank 11, the sodium hydroxide c is dissolved by the process water w to prepare an alkali solution c1 with the concentration of 10% -30%, and the alkali solution c1 is sent to a slurry pool at the lower part of the integrated tail gas purifying device 10. NaOH is adopted as a desulfurization and deacidification agent, the mechanism is similar to that of other desulfurization and deacidification agents, acidic substances such as sulfur dioxide in flue gas are dissolved in dilute acidic solution such as sulfurous acid and the like, the desulfurization and deacidification is carried out on alkaline substances and the dilute acidic solution, and the pH value of circulating slurry is regulated by regulating the addition amount of sodium hydroxide. The ratio of liquid to gas required for absorbing acid gases such as sulfur dioxide and hydrogen chloride and the number of nozzles are determined according to the inlet concentration, the discharge standard and the saturated gas temperature of the acid substances such as sulfur dioxide and hydrogen chloride. The slurry circulating pump 12 pumps out the slurry L1 from the slurry pool, sends the slurry L1 into the slurry heat exchanger 13 to exchange heat with cooling water for cooling, and sends the cooled slurry L2 to the position of the back spray nozzle 10-4 of the turbulent back spray section 10-2 in the integrated tail gas purifying device 10 and the position of the spray nozzle 10-7 above the venturi scrubber 10-6 of the main tower 10-1 by the slurry circulating pump 12 to provide slurry for two-stage flue gas washing.

The high-temperature flue gas g5 enters the turbulent jet section 10-2 of the integrated tail gas purification device 10 from top to bottom after heat exchange by the GGH, the cooling slurry L2 from the slurry heat exchanger 13 is sprayed out of liquid upwards by the jet nozzle 10-4, the sprayed cooling slurry L2 is not atomized, the slurry L2 has different self-rotation centrifugal forces on different positions on the cross section of the turbulent jet section 10-2, the slurry is uniformly dispersed in a radial way under the action of the centrifugal force, the barrel of the turbulent jet section 10-2 is sealed outwards from the center, the slurry L2 is enabled to rotate and turn over microscopically, the surface renewal capacity is improved, the slurry L2 is in strong turbulent contact with the downward flowing high-temperature flue gas g5, the effects of particle trapping, reaction absorption, gas quenching and the like are generated, and the gas purification treatment effect is achieved. The high-temperature flue gas entering the integrated tail gas purifying device at 500+/-20 ℃ is quenched and cooled to below 80 ℃ in a turbulent flow reverse spraying section in a time of not more than 1 second so as to inhibit the regeneration of dioxin.

The high-temperature flue gas g5 enters the main tower 10-1 of the integrated tail gas purification device 10 after being subjected to turbulent jet, flows through the venturi scrubber 10-6 which is arranged at the upper part of the main tower 10-1 and consists of a plurality of venturi tubes from bottom to top, and contains fine particles and water vapor after being subjected to turbulent jet, and when the flue gas goes upwards through the venturi scrubber 10-6, the relative flow velocity between the gas phase and the liquid phase in the shrinkage tube and the venturi tube is very high, the gas is saturated by water, and the gas film attached to the surface of dust particles is broken through, so that the dust particles are wetted by the water, and the fine dust particles and liquid drops or fine dust particles undergo violent collision and condensation; then in the diffuser pipe of the venturi tube, the air flow speed is reduced and the pressure is raised, so that the agglomeration action taking dust particles as agglomerations occurs faster, the dust particles are agglomerated into dust-containing liquid drops with larger particle size, and then the dust-containing liquid drops are captured by the cooling slurry L2 sprayed by the spray nozzle 10-7 at the upper end of the venturi scrubber 10-6. The smoke after being subjected to turbulent jet reverse quenching washing and venturi washing secondary washing and purification is discharged out of the integrated tail gas purification device 10 after the water mist carried by the smoke is removed by a baffle plate demister 10-8 arranged at the upper part of a main tower 10-1; the cooling slurry L2 which is washed and purified for the second time is respectively contacted with the flue gas to form dust-containing slurries with different concentrations, and finally the dust-containing slurries are all collected into a slurry tank of the integrated tail gas purification device 10, the slurry circulation pump 12 and the slurry heat exchanger 13 are used for forming the circulation of the slurry in the integrated tail gas purification device 10, the pH value of the slurry is controlled to be between 6 and 9 according to the consumption of alkaline slurry, and fresh alkaline solution c1 is continuously or discontinuously supplied to the slurry tank through the alkali dissolving tank 11 as required.

Further, a part of the cooled dust-containing slurry L3 cooled by the slurry heat exchanger 13 is sent to the dust-containing slurry spray gun 4-1 of the sludge drying section 4 by the slurry circulating pump 12, is contacted with and collided with the high-temperature flue gas g1, and dries the smoke dust in the dust-containing slurry L3 by utilizing the heat energy of the high-temperature flue gas g 1.

Further, the mist eliminator 10-8 is washed by a mist eliminator water washing nozzle 10-9 arranged above or below the mist eliminator 10-8 periodically or irregularly according to the pressure difference change of the mist eliminator 10-8, water mist and fine particles attached to the surface of the mist eliminator are eluted, and meanwhile, the liquid level of a slurry pool is ensured and the concentration of secondary washing slurry is reduced.

Fourth, heating catalytic reaction stage

The temperature of the low-temperature purified flue gas g6 leaving the integrated tail gas purification device 10 is about 60+/-20 ℃, and the low-temperature purified flue gas g6 enters the GGH heat exchanger 8 to exchange heat with the high-temperature flue gas g4 from the cyclone dust collector 7 to raise the temperature, so that the temperature of the flue gas g8 leaving the GGH heat exchanger 8 is raised to be more than 160 ℃, and the optimal reaction temperature interval in the subsequent catalytic reduction reactor 15 is ensured to be 160-220 ℃.

The purified flue gas g8 leaving the GGH heat exchanger 8 enters the catalytic reduction reactor 15, and after the flue gas is uniformly distributed by an air flow uniformly distributing device, the residual nitrogen oxides in the purified flue gas g8 are further converted into nitrogen by utilizing the gas ammonia u2 provided by the urea solution pyrolyzer 6 under the action of a catalyst in the reactor; simultaneously, under the action of a catalyst, oxidizing and decomposing dioxin and organic pollutants VOCs in the purified flue gas g 8; nitrogen oxides, dioxins and organic pollutants VOCs are simultaneously and efficiently removed through the catalytic reaction in the catalytic reduction reactor 15. The reaction temperature in the catalytic reduction reactor 15 is 160 to 220 ℃, preferably 180 to 200 ℃.

The purified flue gas g9 leaving the catalytic reduction reactor 15 is drawn into a chimney 17 by a draught fan 16 to be discharged to the outside.

Further, the low-temperature purified flue gas g6 discharged from the integrated tail gas purifying device 10 is further purified by the adsorption reactor 18, and the low-temperature purified flue gas g7 leaving the adsorption reactor 18 enters the GGH heat exchanger 8 to exchange gas and heat with the high-temperature flue gas g4 from the cyclone dust collector 7. The two adsorption reactors 18 are arranged in parallel, one is provided with one adsorption reactor 18, when one adsorption reactor 18 works, the other adsorption reactor 18 is desorbed and regenerated, and the two adsorption reactors 18 work alternately, so that the service life of special filter materials or activated carbon/coke in the adsorption reactors 18 can be prolonged, the replacement frequency can be reduced, and the running cost can be reduced.

Further, a part of purified flue gas g10 and/or air a leaving the catalytic reduction reactor 15 is pumped into a regeneration air preheater 20 through a circulating fan 19 to be preheated to obtain preheated gas a3, and when the cremator 1 works in daytime, the preheated gas a3 is introduced into the adsorption reactor 18 to be used as regenerated gas to regenerate special filter materials or activated carbon/coke in the adsorption reactor 18; when the cremator 1 is stopped at night, the circulating gas a4 serving as heat preservation is returned to the catalytic reduction reactor 15 to play a role of heat preservation, so that the working efficiency of the catalytic reduction reactor 15 is improved.

Further, the desorption gas a5 generated after the regeneration of the preheating mixer a3 introduced into the adsorption reactor 18 is fed into the burner 1-3 of the cremator 1 to burn and decompose the pollutants in the desorption gas.

Through the wet treatment process of the cremation furnace incineration tail gas, the emission concentration limit values of smoke dust, sulfur dioxide, nitrogen oxides, carbon monoxide, hydrogen chloride, dioxin and the like of the externally discharged purified smoke gas can be respectively lower than 10mg/m ³ 、30mg/m ³ 、50mg/m ³ 、150mg/m ³ 、30mg/m ³ And 0.5 ng.TEQ/m ³ Meets the requirements of the national current emission standard, and simultaneously realizes the zero emission of sewage in the wet process.

The present application has been described in detail with the purpose of enabling those skilled in the art to understand the contents of the present application and to implement the same, but not to limit the scope of the present application, and all equivalent changes or modifications made according to the spirit of the present application should be covered in the scope of the present application.

Claims

1. The novel cremation machine tail gas wet treatment process method is characterized by comprising the following steps of:

(1) The remains are incinerated in a main combustion chamber of the cremator, the atomized urea solution is sprayed into a hearth of the cremator through a urea spray gun of a secondary combustion chamber for pyrolysis, and SNCR denitration reaction is performed while dioxin generation is inhibited;

(2) The incinerated high-temperature flue gas sequentially passes through a sludge drying section, a urea solution pyrolyzer, a cyclone dust collector and a GGH heat exchanger to be cooled step by step and dedusted;

(3) Introducing the high-temperature flue gas subjected to gradual cooling and dust removal into an integrated tail gas purification device, and sequentially carrying out two-stage washing and purification of turbulent flushing reverse spray quenching washing and venturi washing to carry out integrated purification treatment on the tail gas;

(4) And after the temperature of the low-temperature purified flue gas after the integrated purification treatment is raised through the GGH heat exchanger, introducing the low-temperature purified flue gas into a catalytic reduction reactor for catalytic reaction, and pumping the reacted purified flue gas into a chimney by an induced draft fan for emission.

2. The wet treatment process of tail gas according to claim 1, wherein in the step (1), the oxygen content in the hearth of the cremator is controlled to be 4% -6%, and the pressure in the hearth is controlled to be under a micro negative pressure condition of-50 to-10 Pa, preferably under a micro negative pressure condition of-20 to-10 Pa; the temperature in the hearth of the cremator is within the range of 850-1000 ℃, the residence time of the flue gas after combustion in the secondary combustion chamber in the cremator is not less than 2 seconds, excellent reaction conditions are provided for the SNCR denitration process, and meanwhile, the generation of organic pollutants VOCs and dioxin is reduced.

3. The wet tail gas treatment process according to claim 1, wherein in the step (2), the temperature of the high-temperature flue gas leaving the cremator for burning is 850+/-20 ℃, the high-temperature flue gas enters the sludge drying section, the cooled dust-containing slurry from the integrated tail gas purification device is atomized by compressed air and then sprayed into the sludge drying section through a dust-containing slurry spray gun, the water in the dust-containing slurry is evaporated by utilizing the heat energy of the high-temperature flue gas, the flue gas in the slurry is dried to generate solid particles, the high-temperature flue gas is subjected to preliminary cooling, and the temperature is reduced to 670+/-20 ℃.

4. The wet tail gas treatment process according to claim 1, wherein in the step (2), the high-temperature flue gas leaving the sludge drying section enters the urea solution pyrolyzer, the urea solution is atomized and sent into the urea solution pyrolyzer to perform partition type heat exchange with the high-temperature flue gas by using compressed air, the atomized urea solution is decomposed into gas ammonia by using the heat energy of the high-temperature flue gas, and the gas ammonia is sent into a subsequent catalytic reduction reactor to participate in SCR reaction as a denitration reducing agent, and dioxin is removed.

5. The tail gas wet treatment process according to claim 1, wherein in the step (2), high-temperature flue gas leaving the urea solution pyrolyzer enters the cyclone dust collector tangentially, smoke dust in the flue gas is removed, and the flue gas is collected in an ash bucket at the bottom end of the cyclone dust collector; the smoke dust comprises smoke dust from slurry drying in the sludge drying section.

6. The wet tail gas treatment process according to claim 1, wherein in the step (2), the temperature of the high-temperature flue gas leaving the cyclone dust collector is 660+ -20 ℃, the high-temperature flue gas enters the GGH heat exchanger to exchange gas with low-temperature purified flue gas discharged from the integrated tail gas purification device, the temperature of the high-temperature flue gas after the GGH heat exchange is reduced to 500+ -20 ℃, and then the high-temperature flue gas is sent into the integrated tail gas purification device.

7. The wet treatment process of tail gas according to claim 1, wherein the alkaline solution with the concentration of 10% -30% prepared in the step (3) is sent to a slurry pond at the lower part of the integrated tail gas purification device, a slurry circulating pump pumps slurry from the slurry pond, the slurry is sent to a slurry heat exchanger for cooling and then sent to a back spray nozzle of a turbulent back spray section in the integrated tail gas purification device and a spray nozzle above a venturi scrubber of a main tower, and slurry is provided for two-stage flue gas washing;

the high-temperature flue gas passing through the GGH heat exchanger enters a turbulent flow reverse spray section of the integrated tail gas purification device from top to bottom, the cooling slurry is sprayed out of liquid upwards by the reverse spray nozzle and is in strong turbulent flow contact with the downward flowing high-temperature flue gas, the effects of particle trapping, heavy metal removal, reaction absorption desulfurization deacidification, gas quenching and the like are generated, the gas washing purification treatment effect is achieved, and the high-temperature flue gas entering the turbulent flow reverse spray section is quenched and cooled to below 80 ℃ in no more than 1 second, so that the regeneration of dioxin is inhibited;

the high-temperature flue gas enters a main tower of the integrated tail gas purification device after passing through a turbulent jet reverse spray washing section, flows through a venturi scrubber consisting of a plurality of venturi tubes in the main tower from bottom to top, and firstly passes through a shrinkage tube and a venturi tube of the venturi tubes, and the fine dust particles in the flue gas are subjected to violent collision and condensation with liquid drops or fine dust particles; then quickly condensing into dust-containing liquid drops with larger particle size through a diffusion pipe of a venturi tube, and then capturing cooling slurry sprayed out through a spray nozzle above a venturi scrubber;

The smoke after two-stage washing and purification is discharged out of the integrated tail gas purifying device after the water mist carried by the smoke is removed by a baffle plate demister arranged at the upper part of the main tower; the cooling slurry of the two-stage washing purification is respectively contacted with the flue gas to form dust-containing slurry with different concentrations, and finally the dust-containing slurry is converged into a slurry tank, and slurry circulation is formed in the integrated tail gas purification device through the slurry circulation pump and the slurry heat exchanger, so that the pH value of the circulating slurry is controlled between 6 and 9, and the desulfurization and deacidification efficiency is ensured.

8. The tail gas wet treatment process according to claim 7, wherein the mist and fine particles adhered to the surface of the mist eliminator are eluted by periodically or aperiodically flushing the mist eliminator through a mist eliminator water flushing nozzle arranged above or below the mist eliminator according to the pressure difference change of the mist eliminator, and simultaneously, the liquid level of the slurry pond is ensured and the concentration of the secondary washing slurry is reduced.

9. The method according to claim 1, wherein in the step (4), the temperature of the low-temperature purified flue gas after the integrated purification treatment is 60±20 ℃, and the low-temperature purified flue gas enters the GGH heat exchanger to exchange heat with the high-temperature flue gas to raise the temperature to above 160 ℃; then the purified flue gas enters the catalytic reduction reactor, and after the purified flue gas is uniformly distributed by air flow, nitrogen oxides, dioxins and organic pollutants VOCs are removed simultaneously through catalytic reaction under the action of a catalyst in the reactor; the reaction temperature in the catalytic reduction reactor is 160-220 ℃, preferably 180-200 ℃.

10. The tail gas wet treatment process according to claim 1, wherein the low-temperature purified flue gas after the integrated purification treatment is adsorbed and purified by an adsorption reactor and then enters the GGH heat exchanger to exchange heat with the high-temperature flue gas; the adsorption reactors are arranged in parallel, one adsorption reactor is provided with one adsorption reactor, and when one adsorption reactor works for adsorption, the other adsorption reactor is used for desorption regeneration; filter materials or activated carbon/coke are arranged in the adsorption reactor and are used as adsorption media;

the circulating fan and the regeneration air preheater are used for heat preservation of the catalytic reduction reactor and regeneration of adsorption media in the adsorption reactor, the circulating fan pumps air and/or part of purified flue gas from the catalytic reduction reactor is preheated to 180 ℃ through the regeneration air preheater, when the cremation furnace works in daytime, preheated gas is introduced into one adsorption reactor to regenerate filter materials or activated carbon/coke in the adsorption reactor, and the regenerated analytic gas is sent into the cremation furnace to burn and decompose pollutants in the analytic gas; when the cremator is stopped at night, the preheated gas is used as heat preservation circulating gas to be returned to the catalytic reduction reactor for cyclic heating in order to ensure the temperature required by the catalytic reduction reactor.

11. Novel cremator tail gas wet treatment device is characterized in that, the device includes cremator, cooling dust pelletizing system step by step, integrated tail gas purification device, catalytic reduction reactor and draught fan, chimney, wherein:

the cremator comprises a main combustion chamber and a secondary combustion chamber which are communicated, and a burner and a plurality of air inlets are arranged on a hearth; a urea spray gun is arranged in the secondary combustion chamber;

the progressive cooling and dedusting system comprises a sludge drying section, a urea solution pyrolyzer, a cyclone dust collector and a GGH heat exchanger which are sequentially connected, wherein a flue gas inlet of the sludge drying section is communicated with a flue gas outlet of the cremator;

the integrated tail gas purification device comprises a main tower and a turbulent jet section, the bottom end of the turbulent jet section is communicated with the main tower, the top of the turbulent jet section is an integrated tail gas purification device flue gas inlet, the integrated tail gas purification device is communicated with a high-temperature flue gas outlet of the GGH heat exchanger, and a plurality of upward jet nozzles are arranged in the integrated tail gas purification device; the top of the main tower is an integrated tail gas purification device flue gas outlet, the bottom of the main tower is used as a slurry pool, and a Venturi scrubber, a spray nozzle and a baffle plate demister are sequentially arranged in the main tower from bottom to top; the slurry pool is communicated with the reverse spray nozzle and the spray nozzle through a circulating slurry pump and a slurry heat exchanger;

The exhaust gas outlet of the integrated tail gas purification device is communicated with the low-temperature exhaust gas inlet of the GGH heat exchanger, and the low-temperature exhaust gas outlet of the GGH heat exchanger is communicated with the catalytic reduction reactor, the induced draft fan and the chimney in sequence.

12. The tail gas wet treatment device of claim 11, wherein the inlet of the urea spray gun is in communication with a urea solution tank and an air compressor; the side wall of the sludge drying section is provided with a plurality of dust-containing slurry spray guns, and the inlet of each dust-containing slurry spray gun is communicated with the slurry outlet of the slurry heat exchanger and the air compressor; and a urea solution inlet of the urea solution pyrolyzer is communicated with the urea solution tank and the air compressor, and an ammonia outlet of the urea solution pyrolyzer is communicated with an inlet of the catalytic reduction reactor.

13. The wet tail gas treatment device according to claim 11, wherein the catalytic reduction reactor is internally provided with an air flow uniform distribution device and a plurality of layers of wide-temperature catalysts, the air flow uniform distribution device comprises a diversion grid and a rectification grid and is used for ensuring uniform distribution of flue gas, the wide-temperature catalysts are low-temperature sulfur-resistant molybdenum vanadium titanium catalysts, the activation temperature is not less than 160 ℃, the temperature of flue gas treated by the wide-temperature catalysts is wide, and the catalytic reduction device can be used for catalyzing and eliminating NOx and simultaneously can be used for oxidizing and removing dioxin and organic pollutants VOCs.