CN112725616B - Method for reducing emission of sintering flue gas pollutants by utilizing SCR (selective catalytic reduction) containing waste catalyst pellets - Google Patents
Method for reducing emission of sintering flue gas pollutants by utilizing SCR (selective catalytic reduction) containing waste catalyst pellets Download PDFInfo
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Abstract
The invention discloses a method for reducing emission of sintering flue gas pollutants by utilizing SCR (selective catalytic reduction) containing waste catalyst pellets,belongs to the technical field of pollutant emission reduction in the sintering process. In the preparation process of the sintering raw material, adding sintering pellets, wherein the sintering pellets are sequentially provided with an inner layer pellet, an outer layer pellet and a catalyst layer from inside to outside; the inner pellet comprises an ammonia inhibitor, and the ammonia inhibitor is decomposed by heating to release ammonia; the outer pellet comprises a pore-forming agent, and the pore-forming agent enables pores in the outer pellet to be formed in the sintering process; the catalyst layer comprises an SCR catalyst and vanadium-titanium blast furnace slag. The pore-forming agent in the sintered pellets is heated to decompose to form pores, thereby retarding the decomposition of ammonia inhibitors such as urea and NH 3 Release of (2) to make it react with NO X The emission window period of (2) is consistent, and NO is reduced X Is discharged and breakthrough SO is realized under the action of the catalyst 2 、NO X And the dioxin is cooperated to reduce emission.
Description
Technical Field
The invention relates to the technical field of pollutant emission reduction in a sintering process, in particular to a method for reducing emission of sintering flue gas pollutants by utilizing SCR (selective catalytic reduction) containing waste catalyst pellets.
Background
The sintering/pelletizing process is an important pollution link in the steel industry, the existing flue gas pollutant emission reduction technology generally adopts tail end treatment, and has the advantages of high emission reduction effect, high investment, possibility of secondary pollution and difficulty in realizing multi-pollutant synergistic emission reduction.
Innovative proposal of the Anhui university of industry, long Gongming and the like is that urea is added in a certain specific material layer height interval in the sintering mixture, thermodynamic and kinetic conditions of the sintering process are reasonably utilized, and SO is established 2 、NO X And a dioxin emission barrier, wherein reaction products do not enter sinter nor flue gas, but are intensively discharged along with dust at a specific position of the sintering machine. DeSO by urea method 2 The method has good dioxin removal effect, wide sources of ammonia additives and no secondary pollution problem of reaction products, and is one of effective ways for reducing emission of iron and steel enterprises in the future. But the technique takes off NO X The effect is not ideal, resulting in NO in sintering flue gas X The emission does not meet the existing national emission standard, and few enterprises adopt SCR technology or activated carbon method to treat NO X The process is used for treating NO in flue gas X The control effect of the method is very remarkable, but the input cost and the operation cost are huge, and the emission reduction burden of enterprises is increased. The SNCR process belongs to a non-catalytic in-furnace injection process, is applied to a coal-fired boiler, does not need to add a catalyst, and is to add NH 3 Reducing agents such as ammonia water, urea and the like are directly sprayed into a high-temperature area of the hearth and NO X The denitration rate of the method can reach 30 to 50 percent generally. The denitration process of the SNCR technology needs to control the temperature within 850-1100 ℃, and the temperature of sintering flue gas in actual production is generally below 200 ℃ and does not meet the reaction temperature requirement of ammonia injection denitration. In view of the above, there is an urgent need to seek a suitable solution from the technical and economical point of view to achieve the sintering process SO 2 、NO X And the synergistic emission reduction of dioxin, thereby achieving the purposes of ultra-low emission and low cost treatmentA kind of electronic device.
Some related technical schemes have been disclosed through patent search. Such as: SO in sintering process 2 Method and system for reducing emission of dioxin (CN 104962732B), namely SO in sintering process based on addition of solid inhibitor 2 And a dioxin synergistic emission reduction method (CN 105861816B). With respect to SO during sintering 2 The related technical scheme of online emission reduction is disclosed: an iron ore sintering process desulfurization method based on addition of inhibitors (CN 201110022407.0), an on-line desulfurization method of sintering process (CN 103834800B); the related technical scheme of dioxin emission reduction in the sintering process is disclosed as follows: an emission reduction method of dioxin in the sintering process of iron ore (CN 102847419A), an addition method and a device for reducing the generation of dioxin inhibitor in the sintering process (CN 105316480B). The above disclosed technical solution provides three addition schemes of ammonia inhibitors, (1) adding ammonia inhibitors into the sinter bed in a mixing way, (2) adding ammonia inhibitors at a certain height of the sinter bed, and (3) spraying ammonia inhibitors onto the sinter mixture bed. The technical proposal can realize SO in the sintering process 2 And dioxin, but for NO X The emission does not have good inhibition effect, and SO is difficult to realize 2 、NO X And dioxin to reduce emission.
Disclosure of Invention
1. Problems to be solved
Aiming at the problems that the ammonia inhibitor in the prior art is mainly added into the sintering material in a direct paving or direct mixing granulation mode, and the ammonia inhibitor is rapidly decomposed due to solid heat transfer between the ammonia inhibitor and the sintering material, NH generated by decomposing the ammonia inhibitor can be caused 3 And SO generated by sintering 2 、NO X Inconsistent with the dioxin emission window period, the emission reduction efficiency is reduced; the method for reducing emission of sintering flue gas pollutants by utilizing the SCR-containing waste catalyst pellets is characterized in that porous structure pellets containing ammonia inhibitors can be formed at a specific temperature, so that the ammonia inhibitors are slowly heated to generate NH (NH) 3 With SO 2 、NO X And the dioxin emission window period is consistent,and the emission reduction efficiency is improved.
2. Technical proposal
In order to solve the problems, the technical scheme adopted by the invention is as follows:
in the preparation process of the sintering raw material, adding sintered pellets, wherein the sintered pellets are sequentially provided with an inner pellet, an outer pellet and a catalyst layer from inside to outside; the inner pellet comprises an ammonia inhibitor, and the ammonia inhibitor is decomposed by heating to release ammonia; the outer pellet comprises a pore-forming agent, and the pore-forming agent enables pores in the outer pellet to be formed in the sintering process; the catalyst layer comprises an SCR catalyst and vanadium-titanium blast furnace slag.
Preferably, the specific steps are as follows:
step one: pouring the prepared sintering raw materials and water into a cylinder mixer in sequence for primary mixing, and then carrying out secondary mixing without adding water; after granulating, uniformly adding the manufactured sintered pellets into the sintering raw materials, and uniformly mixing to form a composite sintering raw material;
step two: firstly, paving a primer layer at the lower part of a sintering cup device; paving the mixed and granulated composite sintering raw materials and filling the sintering cup body; finally, ignition and sintering are carried out;
step three: after ignition, carrying out induced draft sintering to NO in the flue gas X 、SO 2 、NH 3 And dioxin on-line measurement.
Preferably, the sintering raw materials include domestic concentrate, king ore, russian fine powder, luo Yishan ore, iron scale, babbitt ore, blast furnace return ore, fly ash, internal return ore, and dolomite as flux, quicklime and coke powder as fuel.
Preferably, the SCR catalyst comprises V2O5 and TiO2; the vanadium-titanium blast furnace slag comprises CaO, siO2, V elements and Ti elements.
Preferably, the granularity of the outer layer pelletizing material reaches-0.149 mm, and the mass percentage content of the grain grade is more than or equal to 95%; the particle size of the inner layer pelletizing material reaches-0.074 mm, and the mass percentage content of the particle size is more than or equal to 95%. The average grain diameter of the outer layer pelleting material is larger than that of the inner layer pelleting material, so that the gaps between mineral powder grains of the outer layer become larger, and the release of ammonium bicarbonate by heating is facilitated.
Preferably, the particle size of the inner pellet is 3-5mm;
and/or the thickness of the outer pellet is 9-11mm;
and/or the granularity of the ammonia inhibitor and the pore-forming agent reaches-0.074 mm, and the mass percentage content of the grain fraction is more than or equal to 95%.
Preferably, the ammonia inhibitor is urea, wherein the content of N element accounts for 0.02-0.15% of the mass of the pellet at the inner layer; the pore-forming agent is ammonium bicarbonate, and the molar ratio of urea to ammonium bicarbonate is (4:1) - (1:4).
Preferably, the water content of the sintered pellets is 8.0-8.5%, and the particle size is 14-18mm.
Preferably, the specific steps are as follows:
step one: sequentially pouring the prepared sintering raw materials into a cylinder mixer for primary mixing, adding a proper amount of water into an air pressurizing machine, spraying the mixture into the mixer through an atomizer to mix with the sintering raw materials, controlling the primary mixing time to be 6min, carrying out secondary mixing after the primary mixing is finished, controlling the secondary mixing time to be 3min without adding water, and controlling the water content of the mixture to be 7.0%; after granulating, uniformly adding the manufactured sintered pellets into the sintering raw materials, and uniformly mixing for 30 seconds to form a composite sintering raw material;
step two:
a) Paving 2kg of base material layer at the lower part of the sintering cup device;
b) Directly paving the uniformly mixed and granulated composite sintering raw materials, filling the sintering cup body, lightly compacting by using a special round cake, and distributing a small amount of sintering raw materials with finer granularity in the concave part;
c) And (5) ignition and sintering. Starting an exhaust fan below the sintering cup, rotating an ignition (device) cover to the position above the sintering cup body, controlling negative pressure to 7kPa through adjusting an air inlet valve and a relief valve, igniting, controlling the air inlet amount and the gas opening, keeping the ignition temperature at about 1150 ℃, and starting timing of sintering. After ignition for 2min, the ignition (device) cover is removed and closed, the negative pressure is adjusted to 14kPa, and a computer in a central control room is started to automatically collect sintering temperature and exhaust negative pressure. And when the temperature of the sintering flue gas reaches the highest value, the temperature starts to drop to be the sintering end point moment, and the timing time t is the complete sintering time. After sintering, adjusting the negative suction pressure to 7kPa, and pouring out the sinter when the temperature of the waste gas is cooled to 300 ℃;
step three: the sintering process includes igniting, exhausting sintering, taking out sintering fume from the sampling port with oil-free vacuum pump, taking gas via parallel gas pipeline, conveying the gas to MCA 10m infrared fume analyzer, and eliminating NO in fume X 、SO 2 、NH 3 And dioxin on-line measurement.
Preferably, the cylinder blendor is sized: phi 600 multiplied by 1200mm, power 8.5kw, and charge 120k;
and/or the specification of the sintering cup operation platform is as follows: 4.0mX3.0m, the inner diameter phi 200 of the sintering cup and the effective height 800mm, the cup body is cast by Cr-containing cast iron, and the charging amount is 50kg.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the method for reducing emission of the sintering flue gas pollutants by using the SCR-containing waste catalyst pellets, in the preparation process of the sintering raw materials, the sintering pellets are added, and the inner-layer pellets, the outer-layer pellets and the catalyst layers are sequentially arranged from inside to outside; the inner pellet comprises an ammonia inhibitor, and the ammonia inhibitor is decomposed by heating to release ammonia; the outer pellet comprises a pore-forming agent, and the pore-forming agent enables pores in the outer pellet to be formed in the sintering process; the catalyst layer comprises an SCR catalyst and vanadium-titanium blast furnace slag. The pore-forming agent in the sintered pellets used in the emission reduction method can generate holes after being decomposed by heating, and the porous structure effectively delays the decomposition of ammonia inhibitors such as urea and NH 3 Release of (2) to make it react with NO X The emission window period of (2) is consistent, and NO is reduced X Discharging; the activity of the portion V, ti of the catalyst promotes the selective reduction of NO by urea X Further improving the denitration efficiency, and simultaneously ensuring that the blocking effect of the catalyst layer is the same asThe sample can play a role in delaying NH 3 For releasing purpose to make it and SO in the flue gas 2 、NO X And the dioxin emission window period is consistent, thereby breakthrough realization of SO 2 、NO X And the dioxin is cooperated to reduce the emission, so that the normal production of sintering operation is ensured, the technical defect of single pollutant end treatment in the prior art is overcome, the pollutant emission reduction cost in the sintering process is greatly reduced, and the emission reduction burden of iron and steel enterprises is reduced.
(2) According to the method for reducing emission of sintering flue gas pollutants by utilizing the SCR-containing waste catalyst pellets, the particle size of the ammonia inhibitor and the pore-forming agent reaches-0.074 mm, and the mass percentage content of the particle size is more than or equal to 95%. The method is favorable for fully and uniformly mixing the raw materials, so that the bonding effect can be fully exerted when the bentonite is dispersed in the pellets, and meanwhile, the adverse effect on the pellet strength caused by high-temperature decomposition of decomposable substances in the bentonite binder is reduced to the minimum, so that the aim of improving the emission reduction efficiency is fulfilled.
(3) The method for reducing emission of sintering flue gas pollutants by utilizing the SCR-containing waste catalyst pellets takes two common and low-cost materials of urea and ammonium bicarbonate as main pelletizing raw materials, has the advantages of wide raw material sources, low cost, high flue gas emission reduction efficiency, reasonable technology, obvious economic benefit and wide application prospect.
Drawings
FIG. 1 is a schematic flow chart of a method for reducing emission of sintering flue gas pollutants by using SCR-containing waste catalyst pellets;
FIG. 2 is a schematic representation of sintered pellets containing inner pellets and outer pellets for use in the present invention;
FIG. 3 is a schematic representation of sintered pellets containing inner pellets, outer pellets and a catalyst layer for use in the present invention.
Reference numerals in the schematic drawings illustrate:
100. inner layer pellet; 200. outer layer pellet; 300. a catalyst layer.
Detailed Description
The invention is further described below in connection with specific embodiments.
Example 1
As shown in fig. 1, in the method for reducing emission of sintering flue gas pollutants by using the waste catalyst pellets containing SCR in the embodiment, in the preparation process of sintering raw materials, sintering pellets are added, and the sintering pellets are sequentially provided with an inner pellet 100, an outer pellet 200 and a catalyst layer 300 from inside to outside; the inner pellet 100 comprises an ammonia inhibitor, and the ammonia inhibitor is decomposed by heating to release ammonia; the outer pellet 200 comprises a pore-forming agent, and the pore-forming agent enables pores in the outer pellet 200 to be formed in the sintering process; the catalyst layer 300 includes an SCR catalyst and vanadium-titanium blast furnace slag, and in this embodiment, the thickness of the catalyst layer 300 is 2mm, and the mass ratio of the SCR catalyst to the vanadium-titanium blast furnace slag in the catalyst layer 300 is 1:1, a step of; the SCR catalyst comprises V2O5 and TiO2; the vanadium-titanium blast furnace slag comprises CaO, siO2, V elements and Ti elements; the inner layer pelleting material comprises domestic concentrate, and the mass percentage content of the granule grade with the granularity of-0.149 mm is more than or equal to 95 percent; the outer layer pelleting material comprises domestic concentrate, and the mass percentage content of the granule grade with the granularity of-0.074 mm is more than or equal to 95 percent; the particle size of the inner pellet 100 is 3-5mm; the water content of the sintered pellets is 8.0-8.5%, and the grain diameter is 12-16mm;
in this embodiment, the ammonia inhibitor is urea, the decomposition temperature of the pore-forming agent is lower than 160 ℃, and here, ammonium bicarbonate with the decomposition temperature of 60-70 ℃ is selected, and the molar ratio of urea to ammonium bicarbonate is 3:2; in addition, the content of N element in the urea accounts for 0.047% of the 100 mass of the pellet in the inner layer, and the mass ratio of the converted urea is 0.1%; the inner layer pelleting material and the outer layer pelleting material in the embodiment are prepared by mixing domestic concentrate and bentonite serving as a binder, and the specific content ratios are as follows:
table 1, pelletizing material dosing table
| Species of type | Guojing | Bentonite clay |
| Additive amount (g) | 2940 | 60 |
In order to verify the advantages and disadvantages of the emission reduction method in the sintering process of the embodiment, SO in the sintering flue gas is detected 2 、NO X And the content change of dioxin is used for analyzing the performance of the sintered pellets, and the specific implementation steps are as follows:
step one: and (3) preparing sintered pellets.
(A) Preparing raw materials: weighing and proportioning the inner layer pelleting material and the outer layer pelleting material according to the weight percentage, adding proper water, controlling the water content to be 8.0%, uniformly mixing, putting the mixture and 5kg steel balls into a moistening mill, setting for 40min for moistening and grinding pretreatment, and screening the granules after moistening and grinding is finished; taking a proper amount of ammonia inhibitor and pore-forming agent, and grinding to fine fraction; mixing a proper amount of ammonia inhibitor with water, and stirring to fully dissolve the ammonia inhibitor to obtain ammonia inhibitor solution;
the particle size of the ammonia inhibitor and the pore-forming agent in the embodiment reaches-0.074 mm, and the mass percentage content of the particle size is more than or equal to 95%; the method is favorable for fully and uniformly mixing the raw materials, so that the bonding effect can be fully exerted when the raw materials are dispersed in the pellets, and meanwhile, the adverse effect on the pellet strength caused by high-temperature decomposition of decomposable substances in the binder bentonite can be reduced to the minimum, thereby achieving the purpose of improving the emission reduction efficiency;
(B) Preparing an inner pellet 100: adding the inner pellet forming material into a disc pelletizer, adding ammonia inhibitor solution, mixing and pelletizing to obtain an inner pellet 100;
in the step, the ammonia inhibitor solution is added in such a way that the ammonia inhibitor solution is firstly placed in a special ammonia inhibitor solution storage device, and is sprayed by a pipeline in the process of preparing the inner core, wherein the ammonia inhibitor solution storage device comprises a storage box, an aluminum pipeline with the diameter of 15mm and a 4-hole spray head; urea is sprayed into the disc pelletizer in a solution form, so that the contact area between the urea and the inner layer pelletizing material can be effectively increased, the self bonding strength of the inner layer pellets 100 is improved, the urea is prevented from being damaged in the subsequent pelletizing or sintering process, and the purpose of improving the urea utilization rate is achieved;
(C) Attaching the outer pellet 200: continuously adding common pelletizing materials and pore-forming agents into the disc pelletizer, and supplementing water to enable the materials to grow into pellets;
(D) Preparation of catalyst layer 300: continuously adding vanadium-titanium blast furnace slag and an SCR catalyst into the disc pelletizer to enable the vanadium-titanium blast furnace slag and the SCR catalyst to grow up, and finally obtaining the sintered pellets.
Step two: pre-granulating.
And (3) sequentially pouring the prepared sintering materials into a cylinder mixer for primary mixing, adding a proper amount of water into an air pressurizing machine, spraying the mixture into the mixer through an atomizer for mixing with the sintering materials, controlling the primary mixing time to be 6min, carrying out secondary mixing after the primary mixing is finished, controlling the secondary mixing time to be 3min without adding water, and controlling the water content of the mixture to be 7.0%. And (3) after the pelletization is finished, uniformly adding the sintered pellets manufactured in the step one into a sintering material, and uniformly mixing for 30 seconds to form a composite sintering raw material.
The sintering materials used in the embodiment comprise domestic concentrate, king ore, russian fine powder, luo Yishan ore, iron oxide scale, barmixed ore, blast furnace return ore, dust and internal return ore, the used flux comprises dolomite and quicklime, the solid fuel is coke powder, the chemical components of the raw materials are shown in table 2, the proportions of the components of the composite sintering raw materials are shown in table 3, and the table does not list all the components of the raw materials, and the components of the raw materials do not reach 100% in total and are other impurities;
table 2 chemical composition of the sintered material (%,. Omega.)
TABLE 3 sintering material formulation/%
Step three: sintered cloth
(A) Paving 2kg of base material layer at the lower part of the sintering cup device;
(B) Directly paving the uniformly mixed and granulated composite sintering raw materials, filling the sintering cup body, lightly compacting by using a special round cake, and distributing a small amount of mixture with finer granularity in the concave part;
(C) And (5) ignition and sintering. Starting an exhaust fan below the sintering cup, rotating an ignition (device) cover to the position above the sintering cup body, controlling negative pressure to 7kPa through adjusting an air inlet valve and a relief valve, igniting, controlling the air inlet amount and the gas opening, keeping the ignition temperature at about 1150 ℃, and starting timing of sintering. After ignition for 2min, the ignition (device) cover is removed and closed, the negative pressure is adjusted to 14kPa, and a computer in a central control room is started to automatically collect sintering temperature and exhaust negative pressure. And when the temperature of the sintering flue gas reaches the highest value, the temperature starts to drop to be the sintering end point moment, and the timing time t is the complete sintering time. And after sintering, adjusting the negative suction pressure to 7kPa, and pouring out the sintered ore when the temperature of the waste gas is cooled to 300 ℃.
Step four: flue gas detection
The sintering process includes igniting, exhausting sintering, taking out sintering fume from the sampling port with oil-free vacuum pump, taking gas via parallel gas pipeline, conveying the gas to MCA 10m infrared fume analyzer, and eliminating NO in fume X 、SO 2 、NH 3 And dioxin were measured on line and emission reduction efficiency was calculated, and the detection results thereof are shown in table 4.
Example 2
The sintered pellets and the sintering emission reduction method of this embodiment are basically the same as those of embodiment 1, except that: in this example, the thickness of the catalyst layer 300 in example 1 was maintained at 1mm, and SO was detected 2 、NO X And the concentration of dioxin produced, recorded in table 4, and the desulfurization and denitrification rate and the emission reduction efficiency of dioxin were calculated.
Example 3
The sintered pellets and the sintering emission reduction method of this embodiment are basically the same as those of embodiment 1, except that: in this example, the thickness of the catalyst layer 300 in example 1 was maintained at 3mm, and SO was detected 2 、NO X And the concentration of dioxin produced, recorded in table 4, and the desulfurization and denitrification rate and the emission reduction efficiency of dioxin were calculated.
Example 4
The sintered pellets and the sintering emission reduction method of this embodiment are basically the same as those of embodiment 1, except that: in this example, the thickness of the catalyst layer 300 in example 1 was maintained at 4mm, and SO was detected 2 、NO X And the concentration of dioxin produced, recorded in table 4, and the desulfurization and denitrification rate and the emission reduction efficiency of dioxin were calculated.
As can be seen by comparing the sintered pellet emission reduction efficiency of the catalyst layers 300 of different thicknesses, SO is between 1-3mm 2 And the emission reduction efficiency of dioxin is basically unchanged, and when the thickness is increased to 4mm, SO 2 、NO X And the dioxin emission reduction efficiency is obviously reduced, which is probably due to the influence of excessive wrapping of the catalyst on the release of ammonia in urea. When the thickness of the catalyst layer 300 is 2mm, NO X The efficiency is highest, and the thickness is optimal from the viewpoints of high efficiency and economy.
Comparative example 1
This comparative example was used as a reference experiment, and the sintering process of this comparative example was the same as in example 1, except that: in the comparative example, urea was not added, and the uniformly mixed sinter was directly added to a sintering device for a sintering cup test. After sintering, SO of flue gas in the sintering process is measured 2 、NO X And the concentration of dioxin, and the emission reduction efficiency was calculated, and the results are recorded as shown in table 4, which is used as a reference for the post-experiment.
Comparative example 2
The sintering process of this comparative example was substantially the same as in example 1, except that: the comparative example adopts the urea adding mode in the traditional urea method: will be mixed with urineThe mixture of the elements is paved in a specific area in the sintering material layer, wherein the specific area refers to that the mixture is distributed in the sintering material at the position of 70-200mm on the sintering trolley, and the rest part adopts the mixture without adding urea for carrying out a sintering cup test. After sintering, SO of flue gas in the sintering process is measured 2 、NO X And the concentration of dioxin and the emission reduction efficiency were calculated and recorded as shown in table 4.
As can be seen from the experimental results of comparative example 1, comparative example 2 and example 1, the urea/ammonium bicarbonate layered pelletization of example 1 is added into the sintering process after being uniformly mixed with the sintering raw material, and compared with the standard experiment without adding urea in comparative example 1 and the sintering experiment in comparative example 2, in which urea is directly paved on a specific material layer for sintering test, SO 2 、NO X The dioxin emission reduction efficiency is improved;
it can be found that the amount of the sintering flue gas released in comparative example 1, which was not added at all, was extremely large, and the pollution to the environment was also extremely large, as compared with comparative example 1; under the action of the sintered pellets prepared by mixing the urea and the ammonium bicarbonate in the embodiment 1, the sintered flue gas SO 2 、NO X And dioxin is effectively reduced in emission, so that the advantage of the technical scheme of preparing sintered pellets by mixing urea and ammonium bicarbonate is shown;
in contrast to comparative example 2, after urea is added to a specific layer, NO in the sintering flue gas X The amount of emissions is substantially unchanged, since the ammonia gas released by pyrolysis of urea is 160℃and NO X The discharge temperature is 850-1250 ℃, and ammonia gas cannot be mixed with NO X The effective contact can quickly leave along with the smoke, and NO is difficult to realize X Is high in efficiency and reduces emission; whereas in example 1 SO is present in the flue gas 2 The discharge amount is 151155mg/m 3 Reduced to 98458mg/m 3 The emission reduction efficiency reaches 83.11%; NO (NO) X The discharge amount is 160428mg/m 3 Reduced to 115468mg/m 3 The emission reduction efficiency reaches 28.73%; the dioxin emission is from 422pg-TEQ/m 3 Reduced to 356pg-TEQ/m 3 The emission reduction efficiency reaches 81.07 percent, and the online SO in the sintering process is realized in a breakthrough way 2 、NO X Synergistic emission reduction of dioxinsThe major technical bottleneck is overcome.
This is because the outer pellet 200 and the catalyst layer 300 can effectively slow down NH 3 Release time to make it match with NO X The emission window period of (2) is consistent, and NO is reduced X The ammonia is not released stably enough, and further, as the outer ammonium bicarbonate particles are decomposed at 60 ℃ to form porous spheres, the heat insulation effect of the porous spheres can lead the urea to release NH 3 Is effective in reducing the rate of (1) to make it release steadily at 600-800 deg.C, and NO X Can be discharged at 650 ℃ and is combined with NH 3 The release temperature interval is agreed so as to react with each other; meanwhile, the generation of dioxin can be inhibited in the cooling process until the temperature of sintering flue gas is reduced below the synthesis temperature of dioxin, SO that SO is improved 2 And dioxin emission reduction efficiency.
Comparative example 3
The sintered pellets and the sintering emission reduction method of this comparative example are basically the same as example 1 except that: sintered pellets of this comparative example were free of catalyst layer 300, and SO was detected 2 、NO X And the concentration of dioxin produced, recorded in table 4, and the desulfurization and denitrification rate and the emission reduction efficiency of dioxin were calculated.
As can be seen from comparative example 1 and comparative example 3, the emission reduction efficiency of SO2 in the flue gas of comparative example 3 is improved from 75.66% to 83.11%, NO X The emission reduction efficiency of (2) is improved from 17.45% to 28.73%, and the emission reduction efficiency of the dioxin emission is improved from 79.73% to 81.07%. This is because the catalyst layer 300 is wrapped outside the outer pellet 200, and urea is promoted to selectively reduce NO by virtue of the activity of the substance V, ti in the catalyst X The denitration efficiency is further improved; while the blocking effect of the catalyst layer 300 can also act to retard NH 3 For releasing purpose to make it and SO in the flue gas 2 、NO X And the dioxin emission window period is consistent, so that the emission reduction efficiency is effectively improved; therefore, in the case of not containing the catalyst layer 300, the emission reduction efficiency of the sintered pellets of the present comparative example is greatly lowered.
Comparative example 4
Sintered pellets of this comparative exampleAnd the sintering emission reduction method is basically the same as that of example 1, except that: the catalyst layer 300 of this comparative example was not added with vanadium-titanium blast furnace slag, and SO was detected 2 、NO X And the concentration of dioxin produced, recorded in table 4, and the desulfurization and denitrification rate and the emission reduction efficiency of dioxin were calculated.
As can be seen from comparative example 1 and comparative example 4, SO2, NO in the flue gas of comparative example 4 X And the reduction efficiency of dioxin are both reduced due to the lack of the synergistic effect of the vanadium-titanium blast furnace slag and the SCR catalyst in the catalyst layer 300 of the present comparative example, but the reduction efficiency of smoke in the present comparative example 4 is significantly improved compared to the comparative example 3, which indicates that the presence of the catalyst can effectively improve the reduction efficiency of smoke.
TABLE 4 SO in sintering test flue gas 2 、NO X And concentration and emission reduction efficiency of dioxin
The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will be understood that various modifications and changes may be made without departing from the scope of the invention as defined by the appended claims. The detailed description and drawings are to be regarded in an illustrative rather than a restrictive sense, and if any such modifications and variations are desired to be included within the scope of the invention described herein. Furthermore, the background art is intended to illustrate the status and meaning of the development of the technology and is not intended to limit the invention or the application and field of application of the invention.
More specifically, although exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, combined, adapted, and/or substituted as would be recognized by one skilled in the art based on the foregoing detailed description (e.g., between the various embodiments), and may be combined as desired. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
Claims (7)
1. The method for reducing emission of sintering flue gas pollutants by utilizing the waste catalyst pellets containing SCR is characterized in that in the preparation process of sintering raw materials, sintering pellets are added, and the sintering pellets are sequentially provided with an inner layer pellet (100), an outer layer pellet (200) and a catalyst layer (300) from inside to outside; the inner pellet (100) comprises an ammonia inhibitor, and the ammonia inhibitor is decomposed by heating to release ammonia; the outer pellet (200) comprises a pore-forming agent, and the pore-forming agent enables pores in the outer pellet (200) to be formed in the sintering process; the catalyst layer (300) comprises an SCR catalyst and vanadium-titanium blast furnace slag, the SCR catalyst comprises V 2 O 5 And TiO 2 The method comprises the steps of carrying out a first treatment on the surface of the The granularity of the outer layer pelletizing material reaches-0.149 mm, and the mass percentage content of the granularity grade is more than or equal to 95%; the mass percentage content of the inner layer pelletizing material with the granularity reaching-0.074 mm grade is more than or equal to 95 percent; the particle size of the inner pellet (100) is 3-5mm;
the thickness of the outer pellet (200) is 9-11mm;
the particle size of the ammonia inhibitor and the pore-forming agent reaches-0.074 mm, and the mass percentage content of the particle size fraction is more than or equal to 95%;
the ammonia inhibitor is urea, wherein the content of N element accounts for 0.02-0.15% of the mass of the pellet at the inner layer; the pore-forming agent is ammonium bicarbonate, and the molar ratio of urea to ammonium bicarbonate is (4:1) - (1:4).
2. The method for reducing emission of sintering flue gas pollutants by utilizing SCR containing waste catalyst pellets according to claim 1, which is characterized by comprising the following specific steps:
step one: pouring the prepared sintering raw materials and water into a cylinder mixer in sequence for primary mixing, and then carrying out secondary mixing without adding water; after granulating, uniformly adding the manufactured sintered pellets into the sintering raw materials, and uniformly mixing to form a composite sintering raw material;
step two: firstly, paving a primer layer at the lower part of a sintering cup device; paving the mixed and granulated composite sintering raw materials and filling the sintering cup body; finally, ignition and sintering are carried out;
step three: after ignition, carrying out induced draft sintering to NO in the flue gas X 、SO 2 、NH 3 And dioxin on-line measurement.
3. The method for reducing emission of sintering flue gas pollutants by using SCR containing waste catalyst pellets according to claim 2, wherein the sintering raw materials comprise domestic concentrate, king ore, russian concentrate, luo Yishan ore, iron oxide scale, bablend, blast furnace return, fly ash, internal return, and dolomite as flux, quicklime and coke breeze as fuel.
4. The method for reducing emission of sintering flue gas pollutants by using SCR-containing waste catalyst pellets according to claim 1, wherein the vanadium-titanium blast furnace slag comprises CaO and SiO 2 And V element and Ti element.
5. The method for reducing emission of sintering flue gas pollutants by using waste catalyst pellets containing SCR as claimed in claim 1, wherein the water content of the sintered pellets is 8.0-8.5%, and the particle size is 14-18mm.
6. The method for reducing emission of sintering flue gas pollutants by using SCR-containing waste catalyst pellets according to any one of claims 1 to 5, which is characterized by comprising the following specific steps:
step one: sequentially pouring the prepared sintering raw materials into a cylinder mixer for primary mixing, adding a proper amount of water into an air pressurizing machine, spraying the mixture into the mixer through an atomizer to mix with the sintering raw materials, controlling the primary mixing time to be 6min, carrying out secondary mixing after the primary mixing is finished, adding no water into the secondary mixing, controlling the secondary mixing time to be 3min, controlling the water content of the mixture to be 7.0%, uniformly adding the prepared sintering pellets into the sintering raw materials after granulating is finished, and uniformly mixing for 30s to form a composite sintering raw material;
step two:
a) Paving 2kg of base material layer at the lower part of the sintering cup device;
b) Directly paving the uniformly mixed and granulated composite sintering raw materials, filling the sintering cup body, lightly compacting by using a special round cake, and distributing a small amount of sintering raw materials with finer granularity in the concave part;
c) Firing and sintering: starting an exhaust fan below a sintering cup, rotating an ignition cover to the position above the sintering cup body, controlling negative pressure to 7kPa through adjusting an air inlet valve and a relief valve, igniting, controlling the air inlet amount and the gas opening, keeping the ignition temperature at 1150 ℃, starting timing during sintering, removing and closing the ignition cover after igniting for 2min, adjusting the negative pressure to 14kPa, starting a central control room computer to automatically collect the sintering temperature and the negative pressure of exhaust, starting to decrease when the temperature of sintering flue gas reaches the highest value, namely the sintering end point moment, adjusting the negative pressure of exhaust to 7kPa after sintering, and pouring out the sintering ore when the temperature of the waste gas is cooled to 300 ℃;
step three: the sintering process includes igniting, exhausting sintering, taking out sintering fume from the sampling port with oil-free vacuum pump, taking gas via parallel gas pipeline, conveying the gas to MCA 10m infrared fume analyzer, and eliminating NO in fume X 、SO 2 、NH 3 And dioxin on-line measurement.
7. The method for reducing emission of sintering flue gas contaminants using SCR containing spent catalyst pellets of claim 6, wherein said cylindrical mixer is sized to: phi 600 multiplied by 1200mm, power 8.5kw and charge 120kg;
and/or the specification of the sintering cup operation platform is as follows: 4.0mX3.0m, the inner diameter phi 200 of the sintering cup and the effective height 800mm, the cup body is cast by Cr-containing cast iron, and the charging amount is 50kg.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002068735A (en) * | 2000-08-24 | 2002-03-08 | Mitsubishi Heavy Ind Ltd | Method for producing ammonia and method for treating exhaust gas |
| CN103498045A (en) * | 2013-09-26 | 2014-01-08 | 中南大学 | Method for reducing emission of flue gas pollutants generated by sintering high sulfur containing pyrites |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1097112A (en) * | 1964-04-28 | 1967-12-29 | Exxon Research Engineering Co | Pressure oscillation of gas during sorption and catalytic processes |
| CA2301667A1 (en) * | 1997-07-24 | 1999-02-04 | Siemens Aktiengesellschaft | Method for operating a sintering plant, as well as sintering plant |
| JP4288212B2 (en) * | 2004-07-02 | 2009-07-01 | 新日本製鐵株式会社 | Exhaust gas treatment method |
| WO2008071215A1 (en) * | 2006-12-14 | 2008-06-19 | Horst Grochowski | Method and device for scrubbing effluent gases from a sintering process for ores or other metal-containing materials in metal production |
| CN102847419A (en) * | 2011-06-30 | 2013-01-02 | 宝山钢铁股份有限公司 | Method for reducing emission of dioxin during iron ore sintering process |
| EP2940162A1 (en) * | 2014-04-30 | 2015-11-04 | Tropinon Enterprises Ltd. | Reuse of titanium-based catalysts |
| CN104028085B (en) * | 2014-05-22 | 2017-01-18 | 武汉钢铁(集团)公司 | Flue gas desulfurization technology based on iron ore sintering process |
| CN104001415B (en) * | 2014-05-29 | 2016-07-06 | 马钢(集团)控股有限公司 | A kind of minimizing sinters SO in flue gas2The method of discharge |
| CN104962732B (en) * | 2014-10-29 | 2017-06-16 | 安徽工业大学 | A kind of sintering process SO2, bioxin cooperates with discharge-reducing method and system |
| CN105861816B (en) * | 2015-01-22 | 2017-08-25 | 安徽工业大学 | A kind of sintering process SO based on addition solid inhibitor2, bioxin cooperates with discharge-reducing method |
| CN106282542B (en) * | 2015-05-13 | 2017-12-19 | 上海梅山钢铁股份有限公司 | A kind of collaboration discharge-reducing method of sintering process multiple pollutant |
| WO2018021511A1 (en) * | 2016-07-29 | 2018-02-01 | 三菱日立パワーシステムズ株式会社 | Exhaust gas denitration catalyst, co oxidation catalyst, exhaust gas treatment system, and exhaust gas treatment method |
| CN109457109B (en) * | 2018-12-28 | 2020-10-02 | 安徽工业大学 | Composite pellet for promoting recycling of metallurgical solid waste resources based on surface layer cladding |
| CN110904332B (en) * | 2019-11-13 | 2021-05-14 | 鞍钢集团矿业有限公司 | Reinforced ammonia spraying denitration method based on iron ore pellet surface catalytic performance |
-
2020
- 2020-12-29 CN CN202011590354.8A patent/CN112725616B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002068735A (en) * | 2000-08-24 | 2002-03-08 | Mitsubishi Heavy Ind Ltd | Method for producing ammonia and method for treating exhaust gas |
| CN103498045A (en) * | 2013-09-26 | 2014-01-08 | 中南大学 | Method for reducing emission of flue gas pollutants generated by sintering high sulfur containing pyrites |
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