Detailed Description
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. 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 to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The temperature of the boiling section in the garbage incinerator is 850-1100 ℃. The temperature of the suspension section in the garbage incinerator is 600-700 ℃.
In view of the problems that the existing garbage incinerator is easy to generate dioxin, the existing denitration technology is difficult to be applied to the treatment of nitrogen oxides of the garbage incinerator and the like, the invention provides a garbage incinerator system and a catalytic removal method of a hearth, wherein the method has the characteristics of purifying waste incineration smoke and preserving heat.
The invention provides a typical implementation mode of a garbage incinerator system, which comprises a garbage incinerator, wherein a smoke outlet of the garbage incinerator is connected with a flue, a heat exchange device is arranged at the smoke outlet of the garbage incinerator, a garbage throwing-in opening of the garbage incinerator is provided with a mixing device, the mixing device is connected with a garbage source and a chlorine inhibitor source, a heat-preservation high-temperature catalyst layer is arranged on the wall of a boiling section of a hearth of the garbage incinerator, a heat-preservation medium-temperature catalyst layer is arranged on the inner walls of a suspension section of the hearth of the garbage incinerator and the flue, and heat-storage ball layers are laid on the surfaces of the heat exchange;
wherein, the chlorine inhibitor is formed by compounding sulfur-containing carbon and calcium oxide;
the heat-insulating high-temperature catalyst is formed by compounding a refractory material and a high-temperature catalyst, and the active component of the high-temperature catalyst contains V2O5、MnxOy、WO3;
The heat-insulating medium-temperature catalyst is made of refractory materialIs formed by compounding with a medium-temperature catalyst, and the active component of the medium-temperature catalyst contains CeO2、FexOy、MgO;
The heat storage ball contains a catalytic active ingredient which is TiO2、SnO2。
Oxide CeO of rare earth metal Ce in the invention2Because of the presence of lattice oxygen in the catalyst, the catalyst of the present invention is a component of the catalyst and is used as a catalyst promoter to catalyze the reaction in cooperation with other catalysts.
In the present invention, the calcium aluminate contains lattice oxygen, and can be used as a catalyst carrier due to its high porosity, so that not only can a carrier material be prepared, but also a refractory material can be prepared due to its use as a main component of cement.
According to the invention, the zeolite molecular sieve is adopted, and the material framework of the zeolite molecular sieve is provided with holes and channels with different sizes, so that the porosity of the material is promoted, and the high temperature resistance of the zeolite molecular sieve also enables the zeolite molecular sieve to be a carrier of the catalyst used in a high-temperature environment. Dioxin is considered to be derived from the burning activity of human beings, is a fat-soluble substance and has carcinogenic hazard to human beings, and is currently mostly combusted in a sufficient manner to limit the discharge of dioxin into the atmosphere. And (3) fully burning, namely, enabling the flue gas to stay in the furnace for more than two seconds at the temperature of more than 850 ℃ so as to completely decompose the dioxin. The method adopts the V-based catalyst to perform catalytic removal on dioxin.
In some embodiments of this embodiment, the chlorine inhibitor is prepared by: mixing sulfur-containing carbon with calcium oxide, and drying.
In one or more embodiments, the mass ratio of sulfur-containing carbon to calcium oxide is 1: 0.5-1.5.
In one or more embodiments, the sulfur-containing carbon and calcium oxide have a particle size of 80 to 100 mesh.
In some examples of this embodiment, the high temperature catalyst is prepared by: mixing and calcining manganese salt, vanadium salt and tungsten salt to obtain a high-temperature catalyst precursor, immersing the high-temperature catalyst precursor in a NaOH solution for treatment, washing the immersed solid until the pH value is 6.8-7.2, drying and calcining to obtain the high-temperature catalyst. The manganese salt is a compound containing manganese ions, such as manganese nitrate. The vanadium salt is a compound containing vanadium ions, such as ammonium metavanadate. The tungsten salt is a compound containing tungsten ions, such as ammonium tungstate.
In one or more embodiments, the molar ratio of the manganese salt, the vanadium salt and the tungsten salt is 1: 0.9-1.1: 0.19-0.21.
In one or more embodiments, the manganese salt, vanadium salt, and tungsten salt are first prepared as a solution, mixed uniformly, dried, and then calcined to obtain the high temperature catalyst precursor. The drying temperature is 160-180 ℃. The drying time is 5-7 h. The calcination temperature is 450-550 ℃, and the calcination time is 3-5 h.
In one or more embodiments, the NaOH solution comprises 15-35% NaOH by weight.
In one or more embodiments, the immersion treatment time is 1 to 3 hours.
In one or more embodiments, the drying process is first draining and then drying with heat. The draining time is 30-90 min. The heating and drying temperature is 65-100 ℃, and the drying time is 2-5 h.
In one or more embodiments, the calcination process is: continuously introducing nitrogen into the calcining furnace, heating the powder to 550-600 ℃ at the speed of 9-11 ℃/min in an oxygen-free atmosphere, and keeping the temperature for 2-4 hours; and then continuously roasting for 1-3 hours at 900-1000 ℃.
In some examples of this embodiment, the medium temperature catalyst is prepared by: mixing and calcining ferric iron salt and cerium salt to obtain a medium-temperature catalyst precursor, immersing the medium-temperature catalyst precursor in a NaOH solution for treatment, washing the immersed solid until the pH value is 6.8-7.2, drying and calcining to obtain a calcined raw material;
adding a copper salt into an oxalic acid solution for treatment, uniformly mixing the copper salt with a calcined raw material and deionized water, drying and calcining to obtain an active component mixture, tabletting the active component mixture, and grinding the active component mixture to 40-60-mesh particles;
carrying out magnetic separation on the steel-making slag powder or the blast furnace slag powder to obtain an iron-rich precursor, and roasting the iron-rich precursor in an air atmosphere to obtain iron-rich particles;
mixing calcium aluminate, iron-rich particles, an active component mixture and zeolite particles, adding deionized water, violently stirring for at least 3 hours, performing ultrasonic dispersion treatment, performing vacuum treatment, and finally roasting to obtain the medium-temperature catalyst.
The ferric salt is a compound containing ferric ions, such as ferric nitrate. The cerium salt is a compound containing cerium ions, such as cerium nitrate. The copper salt is a water-soluble compound having a cation of copper ion, such as copper nitrate, copper sulfate, copper chloride, and the like. The steel slag is taken as solid waste, most of inert metal ions such as Si, Al and the like are removed through magnetic separation, and the active ingredient Fe in the steel slag2O3Can be used as a catalytic active component to CO and NOxAnd the gas is catalytically removed.
In one or more embodiments, the mass ratio of the ferric iron salt to the cerium salt is 1: 0.8-1.2.
In one or more embodiments, the ferric salt and the cerium salt are first prepared into a solution, mixed uniformly, dried, and then calcined to obtain the intermediate-temperature catalyst precursor. The drying temperature is 160-180 ℃. The drying time is 5-7 h. The calcination temperature is 450-550 ℃, and the calcination time is 3-5 h.
And drying the obtained active component mixture at 160-180 ℃. The drying time is 5-7 h. The calcination temperature is 450-550 ℃, and the calcination time is 3-5 h.
In one or more embodiments, the NaOH solution has a mass fraction of NaOH of 15 to 35%.
In one or more embodiments, the immersion treatment time is 1 to 3 hours.
In one or more embodiments, the drying process is first draining and then drying with heat. The draining time is 30-90 min. The heating and drying temperature is 65-100 ℃, and the drying time is 2-5 h.
In one or more embodiments, the calcination process to calcine the powder is: continuously introducing nitrogen into the calcining furnace, heating the powder to 550-600 ℃ at the speed of 9-11 ℃/min in an oxygen-free atmosphere, and keeping the temperature for 2-4 hours; and then continuously roasting for 1-3 hours at 900-1000 ℃.
In one or more embodiments, the mass fraction of oxalic acid in the oxalic acid solution is 3-5%. And stirring the solution by using oxalic acid solution, and directly standing overnight after stirring.
In one or more embodiments, the drying temperature after the oxalic acid solution treatment is 100-120 ℃.
In one or more embodiments, the active component mixture is calcined at a temperature of 400 to 450 ℃ for 1 to 3 hours.
In one or more embodiments, the roasting temperature of the iron-rich particles is 450-550 ℃ and the roasting time is at least 5 hours.
In one or more embodiments, the calcination temperature of the medium-temperature catalyst is 500-550 ℃, and the calcination time is 3-4 h.
In some examples of this embodiment, the heat storage balls are prepared by: adding TiO into the mixture2、SnO2Dispersing in water uniformly, adding urea and hydrochloric acid, heating for hydrolysis, washing the filtered solid, drying, and roasting to obtain composite particles;
grinding the composite particles, and mixing the ground composite particles with corundum and mullite to prepare the heat storage ball.
In one or more embodiments, the concentration of the hydrochloric acid is 36-38% by mass fraction.
In one or more embodiments, the temperature for the heating hydrolysis is 80-90 ℃.
In one or more embodiments, the composite particles are fired at a temperature of 550 to 650 ℃.
In some examples of this embodiment, the method of compositing the catalyst with the refractory material is: mixing the refractory material precursor with a catalyst, pressing into a blank, and roasting. The mixing is carried out by mechanical stirring for more than 10 hours. The pressure of the argon is 10-15 MPa. The roasting process is to heat the mixture to 1000-1050 ℃ at a speed of 15-20 ℃/min, and then to keep roasting for 5-6 h. The mass ratio of the refractory material precursor to the catalyst is 30: 0.9-1.1.
In some examples of this embodiment, the method of compositing the catalyst with the refractory material is: adding a catalyst on the surface of the refractory precursor layer, pressing into a blank, and then roasting. The mixing is carried out by mechanical stirring for more than 10 hours. The pressure of the argon is 10-15 MPa. The roasting process is to heat the mixture to 1000-1050 ℃ at a speed of 15-20 ℃/min, and then to keep roasting for 5-6 h. The mass ratio of the refractory material precursor to the catalyst is 30: 0.9-1.1.
In some examples of this embodiment, the method of compositing the catalyst with the refractory material is: pressing the precursor of the refractory material into a green body, then roasting to form a blocky refractory material or a layered refractory material, spraying mixed slurry of a catalyst and water on the surface of the blocky refractory material or the layered refractory material, and drying. The mass ratio of the blocky refractory material or the layered refractory material to the catalyst is 30: 0.9-1.1.
The precursor of the refractory material is a material before the refractory material is roasted.
In some examples of this embodiment, the refractory material is prepared by: mixing boiler slag waste, building production residual waste and auxiliary foaming additive with powder particles of more than 70 meshes, stirring the mixture overnight by a mechanical stirrer to obtain a mixture, and adding water into the mixture to prepare a slurry-like refractory material precursor. And roasting the slurry-like refractory material precursor to obtain the refractory material.
The boiler slag waste mainly comprises fly ash, coal gangue and the like.
The construction production residual waste mainly comprises muck, waste soil, clay and the like.
The auxiliary foaming additive is mainly sodium dodecyl sulfate or rosin soap foaming agent and the like.
In one or more embodiments, the mass ratio of the boiler slag waste, the building production remaining waste and the auxiliary foaming additive is 20-40:45-55: 5-10.
The invention provides a catalytic removal method for a waste incineration flue gas purification hearth, and provides the waste incinerator system; mixing the garbage particles with a chlorine inhibitor, putting the mixture into a garbage incinerator for incineration, and inhibiting and absorbing chlorine in the incineration;
in the boiling section, heat preservation is carried out under the action of the heat preservation high-temperature catalyst layer, and dioxin is catalytically removed at the same time;
the suspension section is used for preserving heat under the action of the heat-preserving medium-temperature catalyst layer and catalyzing CO to reduce and denitrate nitrogen oxides;
and (3) absorbing heat and reducing the temperature of the generated flue gas by adopting a heat storage ball layer, so that the temperature is reduced to be not higher than 100 ℃, and skipping the optimal temperature interval of secondary synthesis of dioxin.
In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the technical solution of the present invention will be described in detail below with reference to specific examples and comparative examples.
Examples
A waste incinerator system, as shown in FIGS. 1 to 3, comprising: the device comprises a hearth outlet 1, a chimney 2, a tertiary air port 21, a secondary air port 22, a primary air port 21, a hood baffle 3, a peripheral steel frame structure 4, an air inlet 5, a feed inlet 6, an isobaric air chamber 7, a slag cooling pipe 71, a slag falling port 8, a hearth main body 9, a boiling vertical section chlorine inhibitor 91, a boiling section catalytic refractory 92 and a suspension section catalytic refractory 93.
The catalytic refractory 93 for the top suspension section can replace the refractory of the furnace wall of the original suspension section in the furnace with the refractory of the furnace wall of the furnace top, and can combine the original CO in the flue gas to NO in the flue gas in the actual operationxAnd carrying out catalytic removal.
The catalytic refractory material 92 at the boiling section replaces the original furnace wall, the air distribution plate 3 and the surface refractory material at the boiling section in the original furnace, and can effectively catalyze and remove pollutants such as dioxin in flue gas during actual operation.
A suspension section catalytic refractory material 92 is laid on the furnace wall in the ash chamber, and after part of flue gas enters the ash chamber, internal pollutants can still be removed by catalysis of the catalyst at low temperature.
The heat-insulating catalytic material at the garbage throwing inlet 6 and the chimney 2 inlet is consistent with the catalytic refractory material 92 of the suspension section.
The fan 7 and the bottom air port 5 can introduce cold air to rapidly cool the slag and residual smoke in the furnace, so that the slag is cleaned and substances such as dioxin are prevented from being generated again.
The preparation method of the boiling vertical section chlorine inhibitor 91 comprises the following steps:
mixing sulfur-containing carbon and CaO according to the proportion of 1:1, respectively adding into a beaker, pulverizing to 80-100 mesh powder, simultaneously placing the two powders in a drying oven, drying at 60-80 deg.C for 3 hr, mixing the two powders, and storing in dry environment.
The preparation method of the catalytic refractory 92 in the boiling section comprises the following steps:
(1) manganese nitrate, ammonium metavanadate and ammonium tungstate are mixed according to a molar ratio of 1:1: 0.2, preparing a solution, uniformly stirring, drying at 170 ℃ for 6 hours, calcining at 500 ℃ for 4 hours to obtain a monomer, and completely immersing the monomer in a NaOH solution with the mass fraction of 15-35% (immersion), wherein the immersion time is 1-3 hours.
(2) And taking out the monomer from the NaOH solution, washing with deionized water for 4-10 times, ensuring that the pH value of the monomer is 6.8-7.2, taking out the monomer, and draining for 30-90 min.
(3) And (3) putting the mixture into a drying furnace for drying treatment, wherein the drying temperature is 65-100 ℃, and the drying time is 2-5 h.
(4) Placing the powder into a calcining furnace for calcining, continuously introducing nitrogen into the calcining furnace in the calcining process, heating the powder to 550-600 ℃ at a speed of 10 ℃/min in an oxygen-free atmosphere, and keeping the temperature for 3 hours; then the calcination is continued for 2 hours at 900-1000 ℃ to obtain the catalyst.
(5) The catalyst and the refractory material are treated by different loading methods to obtain the catalytic refractory material of the boiling section. Experiments prove that the highest degradation rate of the boiling-section catalytic refractory material to dioxin can reach 84.88% at 950 ℃.
The preparation method of the suspension section catalytic refractory 93 is as follows:
(1) the mass ratio of ferric nitrate to cerous nitrate is 1:1, mixing to form a solution, uniformly stirring, drying at 170 ℃ for 6 hours, calcining at 500 ℃ for 4 hours to obtain a monomer, and completely immersing the monomer in a NaOH solution with the mass fraction of 15-35% (immersion), wherein the immersion time is 1-3 hours.
(2) And taking out the monomer from the NaOH solution, washing with deionized water for 4-10 times, ensuring that the pH value of the monomer is 6.8-7.2, taking out the monomer, and draining for 30-90 min.
(3) And (3) putting the mixture into a drying furnace for drying treatment, wherein the drying temperature is 65-100 ℃, and the drying time is 2-5 h.
(4) Placing the powder into a calcining furnace for calcining, continuously introducing nitrogen into the calcining furnace in the calcining process, heating the powder to 550-600 ℃ at a speed of 10 ℃/min in an oxygen-free atmosphere, and keeping the temperature for 3 hours; then the calcination is continued for 2 hours at 900-1000 ℃ to obtain calcined powder.
(5) Mixing copper nitrate and calcined powder, adding the mixture into 4% oxalic acid solution (the mass ratio of the copper nitrate to the calcined powder to the oxalic acid is 10:10:1), fully stirring, and standing overnight; then drying at the temperature of 100-450 ℃, mixing with calcined powder, adding deionized water until the deionized water is completely dissolved, placing in a calcining furnace, controlling the temperature at 400-450 ℃, and calcining for 2 hours to obtain an active component mixture.
(6) Grinding steel slag particles of a smelting furnace or a blast furnace into particles with the particle size of more than 70 meshes, uniformly stirring, skipping the particles by adopting a magnet, repeatedly operating, separating Si, Al, Mg and the like to obtain an iron-rich precursor, and roasting the iron-rich precursor in an air atmosphere at the temperature of 500 ℃ for more than 5 hours to obtain the iron-rich particles.
(7) Mixing the three substances: after calcium aluminate, iron-rich particles, an active component mixture and zeolite particles are mixed (the mass ratio of the calcium aluminate to the iron-rich particles to the zeolite particles is 1:1:1, and the active component mixture accounts for 10% of the total mass of the mixture), adding deionized water, violently stirring for more than 3 hours, and then carrying out ultrasonic dispersion for more than 1 hour to improve the dispersion performance of each substance; and then vacuumizing the suspension in a vacuum box for vacuum impregnation treatment overnight, and roasting at the temperature of 500-550 ℃ for 3-4 hours to obtain the catalyst.
(8) And treating the catalyst and the refractory material by different loading methods to obtain the suspension-section catalytic refractory material. Experiments prove that the CO decoupling denitration efficiency of the catalyst can reach more than 95% when the suspension section catalytic refractory material is at 650 ℃.
The preparation method of the heat storage ball comprises the following steps:
(1) adding a certain amount of TiO2(the mass fraction is controlled to be not less than 70 percent) and is dispersed in 300mL SnO with the concentration of 20mmol/L by ultrasonic dispersion2In solution.
(2) Immediately after urea (1.2mol/L) was added, the pH of the reaction solution was adjusted to 0.94 with concentrated hydrochloric acid (36-38%).
(3) Heating to 85 deg.C, hydrolyzing at constant temperature for 4 hr, filtering, washing the obtained solid, and drying.
(4) Finally, roasting at 600 ℃ for 2h to obtain the composite particles.
(5) Grinding the obtained composite particles to a specified mesh number, and mixing the composite particles with the mullite by combining a corresponding forming technology to prepare the heat storage ball.
The refractory material is prepared by mixing boiler slag waste (mainly comprising fly ash, coal gangue and the like), building production residual waste (mainly comprising muck, spoil and sludge) and auxiliary foaming additives (mainly comprising sodium dodecyl sulfate and rosin soap foaming agents) in a mass ratio of 20-40:45-55:5-10 with powder particles of more than 70 meshes, stirring the mixture overnight by using a mechanical stirrer, adding deionized water in a mass ratio of 5:1 to the mixture, and stirring the mixture into slurry to obtain a refractory material precursor.
The loading of the catalyst on the refractory material includes three methods: 1) mixing a refractory material precursor and a catalyst according to a mass ratio of 30:1, mechanically stirring for more than 10 hours, pressing into a blank in a mold at a pressure of 10-15Mpa, heating to 1000-1050 ℃ at a speed of 15-20 ℃/min in a muffle furnace, and roasting for 5-6 hours to obtain a catalytic refractory material; 2) putting a refractory material precursor into a mold, coating a catalyst on the surface of the refractory material precursor according to the mass ratio of 30:1, pressing the refractory material precursor into a blank in the mold at the pressure of 10-15Mpa, heating the blank to 1000-1050 ℃ at the speed of 15-20 ℃/min in a muffle furnace, and maintaining the roasting for 5-6 hours to obtain the catalytic refractory material; 3) putting a refractory material precursor into a mold, pressing the refractory material precursor into a blank under the pressure of 10-15Mpa, heating the blank to 1000-1050 ℃ at 15-20 ℃/min in a muffle furnace, and maintaining the roasting for 5-6 hours to obtain the refractory material. Mixing and stirring a catalyst and deionized water in a mass ratio of 30:1 with the refractory material to form slurry, spraying the slurry on the refractory material, and drying to obtain the catalytic refractory material.
The density of the obtained catalytic refractory material is 2.80-2.90 g/cm3The apparent porosity is 15-20, the compressive strength is 85-90 MPa, the refractoriness under load is more than 1400, and the thermal conductivity is 0.05-0.15 kell/m.h.DEG C.
The removal rate of dioxin in the obtained catalyst reaches 80 percent, and the removal rate of NO reaches more than 90 percent.
Based on the internal temperature distribution of the garbage incinerator, the content of the active components of the catalyst in the catalytic refractory material of each section and the catalytic refractory material obtained by different preparation processes are adjusted, and the method is favorable for the active components in the catalytic material: iron, manganese, cerium, magnesium, zeolite, etc. to CO, dioxin, NOxAnd the like, the harmful gases are selectively absorbed and catalytically removed.
The prepared catalytic material should have the following characteristics: 1) the catalyst is uniformly distributed, and can adsorb and remove pollutants in time; 2) the calcium aluminate and the cerium oxide can provide lattice oxygen for oxidizing NO and CO, and are beneficial to NOxRemoving CO; 3) CO in the smoke can be used for reducing NO2The excessive CO can be oxidized by the iron-based and manganese-based active components in the catalytic material; 4) the dioxin pollutants can be removed by the vanadium-based active component in the catalytic material.
The principle is as follows: the rubbish granule is thrown into furnace by throwing into 6, and the granule produces the flue gas at the inside suspension burning of furnace, includes a large amount of pollutants in the flue gas: CO, NOx, dioxins, etc. After the introduction of the pellets, sulfur-containing carbon is combusted in the chlorine inhibitor 91 to form SO in the inlet base 12Has strong inhibiting effect on the generation of chlorine, exerts the chlorine absorbing effect of calcium compounds and controls the chlorine source. In a boiling section with higher temperature, vanadium-based active ingredients in the catalytic refractory material 92 in the boiling section carry out catalytic removal on pollutants such as dioxin; further in the lower temperature suspension section, the suspension section catalyzes the cerium-based, iron-based, and copper-based active components in the refractory material 93 to NOxCarrying out catalytic removal by virtue of CO originally existing in the flue gas; for incineration flue gas discharged from boiler, the catalyst made of cold-storage pellets is quickly cooled to below 100 deg.C so as to easily produce dioxinTemperature interval. Furthermore, the flue gas enters the spiral flue from the flue gas baffle 3, and the iron-based and copper-based active ingredients in the suspension section catalytic refractory 93 attached to the surface of the flue gas baffle 3 and the inner surface of the flue gas oxidize and remove CO and volatile pollutants by means of oxygen existing in the flue gas. Further, after the ash is burnt out, the ash enters the ash chamber through the cold ash pipe 71, part of the residual cooled flue gas enters the interior of the ash chamber, and pollutants in the residual cooled flue gas are continuously removed by the catalytic refractory 93 at the suspension section on the surface of the ash chamber.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.