CN213865977U - Ardealite desulfurization calcination processing system - Google Patents
Ardealite desulfurization calcination processing system Download PDFInfo
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- CN213865977U CN213865977U CN202022009748.1U CN202022009748U CN213865977U CN 213865977 U CN213865977 U CN 213865977U CN 202022009748 U CN202022009748 U CN 202022009748U CN 213865977 U CN213865977 U CN 213865977U
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Abstract
The utility model provides a ardealite desulfurization is calcined processing system, includes low temperature dewatering system, high temperature calcination system and system acid system, low temperature dewatering system includes drying-machine, drying mill and tube furnace in proper order, high temperature calcination system includes preheating device, rotary kiln and cooler in proper order, obtains anhydrous gypsum after drying out the ardealite through low temperature stoving and high temperature grinding and dehydrating natural water and crystal water, carries out the anhydrous gypsum and sends the cement manufacture line as cement raw materials after carrying out high temperature calcination through air cooling, sends into system acid system preparation sulphuric acid after the gas that produces among the calcination process is collected. The utility model discloses part phosphogypsum system acid and cement system, including the resource comprehensive utilization of phosphogypsum dehydration, phosphogypsum decomposition and kiln gas system acid and kiln sediment, can reduce the interference of each other of desulfurization technology and cement technology to ensure to produce high-quality portland cement and high-quality sulphuric acid, realize that the phosphogypsum is innoxious, resourceization and handle in batches greatly.
Description
Technical Field
The utility model belongs to the technical field of the ardealite is calcined and is handled, concretely relates to ardealite desulfurization is calcined and is handled system.
Background
With the development of the phosphorus compound fertilizer industry in China, the utilization of the industrial waste residue phosphogypsum becomes a problem which is not ignored in the development of the industry. One ton per phosphoric acid produced (100% P)2O5) Yielding phosphogypsum 5-6t (dry basis), with a substantial amount of about 7 t. Removing CaSO from phosphogypsum4Besides, the phosphorus ore which is not decomposed and various impurities such as phosphoric acid, calcium fluoride, iron, aluminum compounds, acid insoluble substances, organic matters and the like which are not washed clean are also contained, and the utilization of the phosphogypsum is influenced to a certain extent by the impurities. According to the statistics of relevant data, the annual output of the phosphogypsum in China is 5000-.
At present, the comprehensive utilization approaches of the phosphogypsum mainly comprise: firstly, the phosphogypsum is used for preparing building material products, such as: building gypsum powder, building blocks and the like. Secondly, phosphogypsum manufacturing chemical raw materials, such as: the phosphogypsum is used for preparing sulfuric acid and co-producing cement, and the phosphogypsum is used for preparing potassium sulfate, ammonium sulfate, potassium ammonium sulfate and the like. Thirdly, the phosphogypsum-made cement retarder. Fourthly, phosphogypsum is used as a modifier of saline-alkali soil. Fifthly, preparing calcium sulfate crystal whisker (fibrous gypsum) from phosphogypsum.
The preparation of sulfuric acid and the co-production of cement by using phosphogypsum are important aspects of comprehensive utilization of the phosphogypsum. According to data reports, the external dependence of sulfur resources in China is up to more than 60%, a large amount of imported sulfur is needed each year, and the co-production of the phosphogypsum and the sulfuric acid and the cement can not only fully utilize the resources such as sulfur, calcium and the like in the phosphogypsum, but also reduce the import demand of the sulfur in China to the minimum and effectively suppress the fluctuation of the sulfur market price. Therefore, the development of co-production of cement by using the phosphogypsum to prepare sulfuric acid can effectively relieve the condition of sulfur resource shortage in China.
The co-production of the sulfuric acid and the cement by the phosphogypsum mainly has the following problems: (1) the acid preparation and the cement preparation are synchronously carried out, and the two systems interfere with each other, and the calcining kiln condition is complex, so that on one hand, the calcining kiln condition is complexThe quality of the fired cement clinker is difficult to realize stable, high-quality and high-yield, and on the other hand, SO in kiln gas2The content is low, and the cost for purifying and preparing acid is high; (2) the phosphogypsum decomposition requires a reducing atmosphere, and the cement production cannot generate the reducing atmosphere, so that an unsolvable technical contradiction exists in the production process of producing acid and co-producing cement by a one-step method; (3) in order to increase SO in kiln gas in the process of preparing acid by using phosphogypsum2The content adopts sulfur and the like as reducing agents, but the sublimation and melting of the sulfur easily cause pipeline blockage and influence the safe operation of the cement kiln.
The utility model discloses a system of equipping of scale with industrial waste residue ardealite system anhydrite powder is disclosed in patent CN210419773U, including dosing unit, upright mill dust arrester installation, raw meal conveyor, raw meal storehouse, raw meal measurement feed conveyor, combined cyclone preheater, fluidized bed furnace, hot-blast furnace, heat transfer conveyer, cooked powder conveyor and cooked powder storehouse. Utilize the utility model discloses equipment the system, use the industrial waste residue ardealite to make anhydrite powder as the raw materials, can directly absorb hydrous ardealite in a large number, carry out synchronous modification to hydrous ardealite, it is dry, the grinding, and can accomplish "dehydration + calcination" process fast, and easily effective control calcination quality, the energy consumption is low, although this application is "dehydration + calcination" process, but the final product of gas preparation is anhydrite, actually be anhydrous calcium sulfate, only realize the dehydration process, do not realize real desulfurization process, its product also can not be used for making sour process, still belong to the preparation building gypsum category, unable batch processing ardealite.
SUMMERY OF THE UTILITY MODEL
In order to overcome the problem among the prior art, the utility model provides a phosphogypsum desulfurization is calcined processing system, after the phosphogypsum removed from natural water and crystal water through low temperature stoving grinding and high temperature flash firing, carries out the high temperature and calcines, then sends to the cement manufacture line as cement raw materials after through air cooling, the SO that produces among the calcination process2The gas is collected and then sent to an acid making system to prepare sulfuric acid, so that the mutual interference of a desulfurization process and a cement process is reduced, high-quality portland cement and high-quality sulfuric acid are produced, and the harmlessness, the recycling and the large-scale disposal of the phosphogypsum are realized.
In order to achieve the above object, the utility model discloses a following technical scheme realizes:
the utility model provides a ardealite desulfurization is calcined processing system, calcine system and system sour system including low temperature dewatering system, high temperature, low temperature dewatering system includes drying-machine, drying mill and pipe-line furnace in proper order, the high temperature is calcined the system and is included preheating device, rotary kiln and cooler in proper order.
The feed inlet of the dryer is connected with the material conveying device, the discharge outlet of the dryer is connected with the feed inlet of the drying mill, the discharge outlet of the drying mill is connected with the feed inlet of the pipeline furnace, the discharge outlet of the pipeline furnace is connected with the air inlet of the preheating device, the air outlet of the preheating device is connected with the acid making system, the discharge outlet of the preheating device is connected with the feed inlet of the rotary kiln, the flue gas outlet of the rotary kiln is connected with the air inlet of the preheating device, and the discharge outlet of the rotary kiln is connected with the feed inlet of the cooler; and the low-temperature steam of the acid making system is connected with a steam pipeline inlet of the dryer through a pipeline.
In a preferred embodiment, the dryer is a mesh belt dryer, low-temperature steam and low-temperature flue gas are used as drying heat sources, a flue gas outlet of the mesh belt dryer is connected with an air inlet of a bag-type dust remover, purified flue gas is discharged harmlessly through an exhaust fan, and a discharge port of the bag-type dust remover is connected with a feed port of the mesh belt dryer.
In a preferred embodiment, the bottom of the drying mill is provided with a flue gas inlet, the flue gas inlet is connected with a fluidized bed furnace, the pipe furnace is of a hollow tubular structure, the upper part of the pipe furnace is provided with a discharge hole, the lower part of the pipe furnace is provided with a feed hole, and the verticality of the pipe furnace is not less than 75 degrees.
In a preferred embodiment, a cyclone separator is further arranged between the pipeline furnace and the preheating device, the discharge port of the pipeline furnace is connected with an air inlet of the cyclone separator, and an air outlet of the cyclone separator is connected with an air inlet of the dryer.
In a preferred embodiment, the preheating device is composed of at least 2 stages of cyclone preheaters which are vertically connected in series, an air outlet of the first stage of cyclone preheater is connected with an acid making system, an air outlet pipeline of the second stage of cyclone preheater is connected with an air inlet pipeline of the first stage of cyclone preheater, a discharge port of the first stage of cyclone preheater is connected with an air inlet pipeline of the second stage of cyclone preheater through a pipeline, the rest is done in sequence, an air inlet pipeline of the last stage of cyclone preheater is connected with a kiln tail flue gas chamber of the rotary kiln, and a discharge port of the last stage of cyclone preheater is connected with a kiln tail feed inlet of the rotary kiln.
In a preferred embodiment, the kiln tail flue gas chamber of the rotary kiln is further connected with a reducing agent storage, a kiln head of the rotary kiln is provided with a kiln head cover, a burner is arranged in the kiln head cover and connected with a fuel storage, the lower part of the kiln head cover is connected with a feed inlet of the cooling machine, the rotary kiln inclines from a feed end to a discharge end, and the inclination degree is 3-5%.
In a preferred embodiment, the lower part of the cooler is provided with a high-temperature section air inlet and a low-temperature section air inlet, and the cooler air outlet is connected with the high-temperature section air inlet of the cooler after passing through the cyclone dust removal device.
In a preferred embodiment, the treatment system further comprises a slag storage device, the slag storage device comprises a slag storage warehouse, a feed inlet of the slag storage warehouse is connected with the dust remover through an air draft device, and an air outlet of the dust remover is connected with an air inlet of the low-temperature section of the cooler.
In a preferred embodiment, an air heat exchanger and a high-temperature dust collector are further arranged between the air outlet of the first-stage cyclone preheater and the acid making system, a smoke inlet of the air heat exchanger is connected with the air outlet of the first-stage cyclone preheater, a smoke outlet of the air heat exchanger is connected with a smoke inlet of the high-temperature dust collector, and a smoke outlet of the high-temperature dust collector is connected with the acid making system.
In a preferred embodiment, the drying mill comprises one of a vertical mill, an air swept steel ball mill, a roller press, a column mill.
The treatment method for desulfurization and calcination of phosphogypsum by using the system comprises the following steps:
s1, drying the phosphogypsum in a mesh belt type dryer at the temperature of 120-160 ℃ to remove natural water in the phosphogypsum, drying the powder by a drying mill at the temperature of 500 ℃ to remove crystal water to generate anhydrous gypsum powder, and conveying the anhydrous gypsum powder into a preheating device through a pipeline furnace;
s2, preheating the anhydrous gypsum powder prepared in the S1 to 800-850 ℃, sending the anhydrous gypsum powder into a rotary kiln, adding fuel and a reducing agent into the rotary kiln, then calcining at high temperature, wherein the calcining temperature is 1000-1400 ℃, and cooling and storing the generated slag through air;
s3, collecting sulfur dioxide gas generated in the calcining process in the step S2, sending the collected gas into an acid making system to prepare sulfuric acid, and sending the stored slag into a cement production line to be used as a cement raw material.
The utility model discloses beneficial effect as follows:
(1) the utility model adopts the mesh belt type dryer, the drying mill and the pipeline furnace for drying, a multi-stage cyclone preheater is utilized for preheating, finally, the rotary kiln is utilized for suspension calcination, the low-temperature dehydration and the pyrolysis of the phosphogypsum are completed in two steps, the phosphogypsum is dried by the mesh belt type dryer and then natural water is removed, the water entering the drying mill is controlled, the blockage of devices such as the pipeline can not be caused, the fineness of the phosphogypsum is reduced by low-temperature drying and grinding, conditions are created for accelerating the dehydration and the desulfurization speed, simultaneously, crystal water is removed by high-temperature heating in the drying and grinding process to obtain anhydrous gypsum, then the anhydrous gypsum enters the preheating device through the pipeline furnace, the anhydrous gypsum enters a desulfurization calcination system composed of the cyclone preheater, the rotary kiln and the cooler, the phosphogypsum is preheated by the cyclone preheater and decomposed in the rotary kiln under the high-temperature reducing atmosphere, recovery of SO from kiln gas2And the slag is high-CaO slag, which can be used as a calcareous raw material for cement production to replace limestone, or as a basic raw material to be used as building lime, building blocks, low-grade cement and the like.
(2) The utility model discloses a mesh belt formula drying-machine adopts the low temperature waste heat that produces in the system acid as the heat source, is favorable to the energy saving, adopts the drying mill that has stoving and powder function concurrently, and the ardealite granularity after the stoving grinding is even, can improve the product fineness as required, is favorable to accelerating the ardealite dehydration and calcines the decomposition. A calcining system consisting of a cyclone preheater and a rotary kiln is adopted, so that the dehydrated phosphogypsum enters the rotary kiln to be calcined after being preheated to 850 ℃, the calcining temperature can reach about 1200 ℃, and the phosphogypsum is combusted in an anoxic state in the rotary kiln to generate reducing atmosphere, thereby effectively accelerating the decomposition reaction.
(3) The utility model discloses in adopt through the cooler of improvement, adopt the air to force to blow cold slag, after the heat exchange, in the heated air gets into the rotary kiln, for the air capacity in the control kiln, this application adopts the series connection mode to use low temperature section cooling air as high temperature section wind after removing dust to reduce the income kiln air capacity and improve the income kiln temperature. Meanwhile, residual CaS in the slag is further oxidized by oxygen in the air to generate CaO, so that the sulfur in the phosphogypsum is thoroughly removed.
(4) The utility model discloses part phosphogypsum system acid and cement system, including the resource comprehensive utilization of phosphogypsum dehydration, phosphogypsum decomposition and kiln gas system acid and kiln sediment, can reduce the interference of each other of desulfurization technology and cement technology, can produce high-quality portland cement and high-quality sulphuric acid. The whole system has advanced and reliable equipment, saves capital investment, can realize scientific and comprehensive utilization of energy compared with other kiln types, and has low total energy consumption, high gypsum decomposition rate, large processing capacity and large production scale.
Drawings
FIG. 1 is a schematic diagram of a treatment system according to the present invention;
the above reference numerals:
11. weighing; 12. a belt conveyor; 13. a dryer; 14. a bag-type dust collector; 15. a drying mill; 16. a fluidized bed furnace; 17. a pipeline furnace; 18. a cyclone separator;
211. a first stage cyclone preheater; 212. a second stage cyclone preheater; 213. a third stage cyclone preheater; 214. a fourth stage cyclone preheater;
22. a rotary kiln; 23. a reductant reservoir; 24. a burner; 25. a fuel reservoir; 26. a cooling machine; 27. a cyclone dust removal device;
221. a flue gas chamber; 222. a kiln head cover;
32. a high temperature dust remover; 33. an acid making system;
41. a slag storage reservoir; 42. a dust remover.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Example 1
As shown in fig. 1, the present embodiment provides a phosphogypsum desulfurization and calcination treatment system, which includes a low-temperature dehydration system, a high-temperature calcination system and an acid making system, wherein the low-temperature dehydration system sequentially includes a dryer 13, a drying mill 15 and a pipeline furnace 17, and the high-temperature calcination system sequentially includes a preheating device, a rotary kiln 22 and a cooler 26.
The feed inlet of drying-machine 13 links to each other with material transfer device, the discharge gate of drying-machine 13 links to each other with the feed inlet of stoving mill 15, the discharge gate of stoving mill 15 links to each other with the feed inlet of pipe-line furnace 17, the discharge gate of pipe-line furnace 17 links to each other with preheating device's air intake, preheating device's air outlet links to each other with system acid 33, preheating device's discharge gate links to each other with the feed inlet of rotary kiln 22, the exhanst gas outlet of rotary kiln 22 links to each other with preheating device's air intake, the discharge gate of rotary kiln 22 links to each other with the feed inlet of cooler 26, system acid 33's low temperature vapor pipeline links to each other with the low temperature vapor pipeline import of drying-machine 13.
Preferably, the dryer 13 is a mesh belt dryer, low-temperature steam and low-temperature flue gas are used as drying heat sources, a flue gas outlet of the mesh belt dryer is connected with an air inlet of the bag-type dust collector 14, purified flue gas is discharged harmlessly through an exhaust fan, and a discharge port of the bag-type dust collector 14 is connected with a feed port of the mesh belt dryer.
Preferably, the bottom of the drying and grinding machine 15 is provided with a flue gas inlet, wherein the flue gas inlet is connected with the fluidized bed furnace 16, the pipe furnace 17 is of a hollow tubular structure, the upper part of the pipe furnace is provided with a discharge hole, the lower part of the pipe furnace is provided with a feed hole, and the verticality of the pipe furnace 17 is not less than 75 degrees.
Preferably, a cyclone separator 18 is further arranged between the pipeline furnace 17 and the preheating device, a discharge port of the pipeline furnace 17 is connected with an air inlet of the cyclone separator 18, and an air outlet of the cyclone separator 18 is connected with an air inlet of the dryer 13.
In the embodiment, after being put into a factory by a vehicle, the phosphogypsum is conveyed into a discharge pit in a discharge warehouse for discharging, after being weighed by a scale 11, the phosphogypsum is conveyed into a dryer 13 for drying by a belt conveyor 12, the drying temperature is about 120 ℃ plus 160 ℃ for removing natural water in the phosphogypsum, a drying heat source is from low-temperature waste heat generated by an acid making system 33 and hot flue gas generated after materials discharged by a pipeline furnace 17 are separated by a cyclone separator 18, the flue gas generated after drying is conveyed into a bag-type dust collector 14 through a flue gas outlet at the upper part of the dryer 13, and the purified gas can be discharged without pollution. In this embodiment, the bag-type dust collector 14 is an anti-dew bag-type dust collector.
The phosphogypsum discharged from the dryer 13 enters a drying and grinding machine 15 for powder and drying, the particle of the powder is controlled to be 30-65um, hot flue gas used for drying by the drying and grinding machine 15 comes from high-temperature flue gas generated by coal calcination by a fluidized bed furnace 16, and the flue gas with the temperature of about 500 ℃ is conveyed into the drying and grinding machine 15 by a high-temperature fan; in the production process, the drying flue gas required by the drying and grinding machine 15 comes from the heat discharged by the preheating device and passing through the air heat exchanger, and the phosphogypsum particles in the drying and grinding machine 15 are dehydrated to remove crystal water at the temperature of about 500 ℃. In a specific embodiment, the drying mill 15 includes a vertical mill, an air swept steel ball mill, a roller press, a column mill, a raymond mill, or the like, and a vertical mill is used in the present embodiment. In this embodiment, the tube furnace 17 is a vertical tube, the upper part of the tube furnace is provided with a discharge port, the lower part of the tube furnace is provided with a feed port, the wind speed in the tube is 8-15m/s, and the phosphogypsum powder particles pass through the tube furnace 17 and then enter the cyclone separator 18.
In this embodiment, after passing through the tube furnace 17, the phosphogypsum particles from which crystal water is rapidly removed at high temperature enter the cyclone separator 18 for solid and gas separation, and the separated gas is discharged through the air outlet at the top of the cyclone separator 18 and then is sent into the air inlet of the dryer 13 to be used as hot flue gas for drying by the dryer 13. The solids are discharged from a discharge port at the lower part of the cyclone 18 and then sent into a preheating device.
Preferably, the preheating device is composed of at least 2 stages of cyclone preheaters which are vertically connected in series, an air outlet of the first stage of cyclone preheater 211 is connected with an acid making system, an air outlet pipeline of the second stage of cyclone preheater 212 is connected with an air inlet pipeline of the first stage of cyclone preheater 211, a discharge port of the first stage of cyclone preheater 211 is connected with an air inlet pipeline of the second stage of cyclone preheater 212 through a pipeline, and so on, an air inlet pipeline of the last stage of cyclone preheater is connected with a kiln tail flue gas chamber 221 of the rotary kiln 22, and a discharge port of the last stage of cyclone preheater is connected with a kiln tail feed inlet of the rotary kiln 22.
In this embodiment, the preheating device is composed of four-stage cyclone preheaters which are vertically connected in series, an air outlet of the first-stage cyclone preheater 211 is connected with the acid making system 33, an air inlet pipeline of the first-stage cyclone preheater 211 is connected with an air outlet pipeline of the second-stage cyclone preheater 212, a discharge port of the first-stage cyclone preheater 211 is connected with an air inlet pipeline of the second-stage cyclone preheater 212 through a pipeline, an air inlet pipeline of the second-stage cyclone preheater 212 is connected with an air outlet pipe of the third-stage cyclone preheater 213, and so on, a discharge port of the third-stage cyclone preheater 213 is connected with a flue gas chamber 221 at the kiln tail of the rotary kiln 22, an air inlet pipeline of the fourth-stage cyclone preheater 214 is connected with a flue gas chamber 221 at the kiln tail of the rotary kiln 22, a discharge port of the fourth-stage cyclone preheater 214 is connected with a kiln tail feed inlet of the rotary kiln 22, a temperature of a material just entering the cyclone preheater is about 350 ℃, and the material is heated to about 850 ℃ after being preheated by the four-stage.
Preferably, the kiln tail flue gas chamber 221 of the rotary kiln 22 is further connected with the reducing agent storage 23, the kiln head of the rotary kiln 22 is provided with a kiln head cover 222, a burner 24 is arranged in the kiln head cover 222, the burner 24 is connected with the fuel storage 25, the lower part of the kiln head cover 222 is connected with the feeding hole of the cooling machine 26, and the rotary kiln 22 inclines from the feeding end to the discharging end, wherein the inclination degree is 3-5%.
Preferably, the lower part of the cooler 26 is provided with a high-temperature section air inlet and a low-temperature section air inlet, and the cooler air outlet is connected with the cooler high-temperature section air inlet after passing through the cyclone dust removal device 27.
In this embodiment, a flue gas chamber 221 is arranged at the upper part of the kiln tail of the rotary kiln 22, a feed inlet is arranged at the kiln tail, a discharge outlet is arranged at the kiln head, a kiln head cover 222 is arranged at the discharge outlet, a pulverized coal burner 24 is arranged in the kiln head cover 222 and connected with a fuel storage 25, an air locking valve is arranged at the discharge outlet at the lower part, and the lower part is connected with a scale. The fuel is anthracite, bituminous coal and high-sulfur coal, and the high-sulfur coal with higher calorific value is preferably used as the fuel. The kiln tail flue gas chamber 221 is connected with a reducing agent storage 23, a discharge port at the lower part of the reducing agent storage 23 is provided with an air locking valve, the lower part is connected with a metering scale, in the embodiment, the reducing agent is coke powder or anthracite, the fineness is controlled to be about 0.5-1mm, and the reducing agent is added according to 10-30% of the dry basis weight of the phosphogypsum. The rotary kiln 22 is inclined from the feeding end to the discharging end, the inclination degree is 3-5%, the length of the rotary kiln 22 is based on ensuring the sufficient residence time of the phosphogypsum, and the residence time is generally designed to be 0.5-2 h.
The lower part of the kiln head cover 222 of the rotary kiln 22 is connected with a cooler 26, the cooler 26 is cooled by air, the lower part is provided with a high-temperature section air inlet and a low-temperature section air inlet, an air outlet of the cooler 26 passes through a cyclone dust removal device 27 and then is connected with the high-temperature section air inlet of the cooler 26, and in the embodiment, the cooler 26 is a grate cooler.
In the specific implementation process, the anhydrous phosphogypsum is preheated and then enters the rotary kiln 22 for calcination after the temperature reaches 850 ℃, fuel is sprayed into the kiln head of the rotary kiln 22 for combustion so that the calcination temperature in the rotary kiln 22 can reach 1000-1400 ℃, a reducing agent is added into the kiln tail so that the fuel is combusted in an anoxic state to generate a reduction atmosphere, wherein the reducing agent is coal or coke powder, the generated slag is discharged in the calcination process in the rotary kiln 22 and then enters the grate cooler for air cooling, air is introduced to completely oxidize CaS (calcium sulfide) remained in the slag into CaO, and oxygen-enriched air can be used for reducing the air quantity entering the kiln. In this embodiment, in order to reduce the amount of air entering the kiln and increase the temperature of the air entering the kiln, the cooling air at the low temperature stage is collected by the cooler and used as the cooling air at the high temperature stage after passing through the cyclone dust collector 27. In the rotary kiln 22, because coal added at the tail of the kiln and phosphogypsum generate a carbon thermal reduction reaction in an anoxic state, in order to ensure a reduction atmosphere, redundant cooling air of the grate cooler is directly sent into a preheating device through a bypass pipeline, the content of CO in flue gas discharged from the rotary kiln 22 is controlled to be 3-5%, and O is brought in due to possible air leakage after the flue gas enters a cyclone preheater system2Oxidation to oxidize CO in the flue gas into CO2。
Preferably, an air heat exchanger and a high-temperature dust collector 32 are further arranged between the air outlet of the first-stage cyclone preheater 211 and the acid making system 33, a smoke inlet of the air heat exchanger is connected with the air outlet of the first-stage cyclone preheater 211, a smoke outlet of the air heat exchanger is connected with a smoke inlet of the high-temperature dust collector 32, and a smoke outlet of the high-temperature dust collector 32 is connected with the acid making system 33.
In this embodiment, SO generated by the calcination decomposition in the rotary kiln 222The gas enters the preheating device through the kiln tail gas chamber 221 of the rotary kiln 22, is discharged from the first-stage cyclone preheater 211, exchanges heat in the air heat exchanger, enters the high-temperature dust remover 32 for dust removal, and enters the well-known SO2Gas acid making system 33, after exchangeThe heat is transmitted to a drying mill for phosphogypsum.
Preferably, the treatment system further comprises a slag storage device, wherein the slag storage device comprises a slag storage warehouse 41, a feed inlet of the slag storage warehouse is connected with the dust remover 42 through an air draft device, and an air outlet of the dust remover 42 is connected with an air inlet of the low-temperature section of the cooler.
In this embodiment, the slag obtained by the desulfurization and calcination system is cooled and then directly sent to the slag storage 41 for storage by using a closed elevator, the conveying equipment and the slag storage 41 adopt fans for concentrated air draft and are treated by a dust collector 42 to be used as air for the low temperature section of the grate cooler, and the slag is fed into a known cement production line to be used as a cement raw material. All air pipes and equipment in the system are pasted with heat insulation materials.
Example 2
The treatment steps of the household garbage by using the treatment system are as follows;
firstly, preparing the anhydrous phosphogypsum
The ardealite is delivered into a discharge pit in a discharge warehouse for discharging after being delivered into a factory by a vehicle, and is delivered into a mesh belt type dryer for drying after being weighed by a weighing scale, natural water is removed by low-temperature heating at the temperature of about 120 plus 160 ℃, a drying heat source is from low-temperature waste heat generated by an acid making system and hot flue gas generated after materials discharged by a pipeline furnace are separated by a cyclone separator, the flue gas generated after drying is delivered into a bag-type dust collector through a flue gas outlet at the upper part of the dryer, and the purified gas can be discharged without pollution.
Feeding the phosphogypsum discharged from the mesh belt type dryer into a drying mill for powder and drying, controlling the particle size of the powder to be 30-65um, wherein hot flue gas for drying of the drying mill is from high-temperature flue gas generated by coal calcination in a fluidized bed furnace, and conveying the flue gas at about 500 ℃ into a vertical mill through a high-temperature fan for removing residual crystal water of the phosphogypsum; in the production process, the drying flue gas required by the vertical mill can also come from heat generated after heat exchange in the air heat exchanger.
The phosphogypsum powder particles from which the crystal water is quickly removed at high temperature pass through a pipeline furnace and then are sent into a cyclone separator, solid and gas are separated by the cyclone separator, and the separated gas is discharged through an air outlet at the top of the cyclone separator and then is sent into an air inlet of a vertical mill to be used as hot flue gas for drying the vertical mill. And discharging the solid from a discharge port at the lower part of the cyclone dust collector and then conveying the solid into the preheating device.
Desulfurization and calcination system for phosphogypsum
The temperature of the phosphogypsum powder particles just entering the cyclone preheater is about 350 ℃, the phosphogypsum powder particles are heated to about 850 ℃ after passing through the four-stage cyclone preheater and enter the rotary kiln, fuel is sprayed into the kiln head of the rotary kiln to be combusted, so that the calcining temperature in the rotary kiln can reach 1000-1400 ℃, preferably 1200 ℃, the fuel is anthracite, bituminous coal and high-sulfur coal, and the high-sulfur coal with higher heat value is preferably used as the fuel. Adding a reducing agent at the tail of the kiln to enable the fuel to burn in an anoxic state to generate a reducing atmosphere, wherein the reducing agent is coal or coke powder, and the phosphogypsum is burnt in a rotary kiln to generate CaS, CaO and SO2、CO2And CO gas. And discharging the slag generated after combustion, cooling the slag in a sectional grate cooler by oxygen-enriched air, and introducing air to completely oxidize residual CaS in the slag into CaO, so that the sulfur in the phosphogypsum is completely removed.
In order to reduce the air quantity entering the kiln and improve the air temperature entering the kiln, the cooling air at the low-temperature section is collected through a cooling machine and used as the cooling air at the high-temperature section after passing through a cyclone dust removal device. In the rotary kiln, coal added at the tail of the kiln and phosphogypsum generate a carbon thermal reduction reaction in an anoxic state, and redundant cooling air of the grate cooler is directly sent into the preheater through a bypass pipeline in order to ensure a reducing atmosphere.
The content of CO in the flue gas discharged from the rotary kiln is controlled to be 3-5%, and O is brought in due to possible air leakage after entering a cyclone preheater system2Oxidation to oxidize CO in the flue gas into CO2. SO generated by calcination decomposition in rotary kiln2The gas enters the cyclone preheater through the rotary kiln gas chamber and is discharged along with the gas, enters the high-temperature dust remover after passing through the air heat exchanger for dust removal and then enters the known acid making system, namely, after sulfur dioxide is oxidized into sulfur trioxide, the sulfur trioxide is washed by dilute sulfuric acid water to form sulfuric acid. In the gasThe carbon dioxide does not go into solution.
Thirdly, slag treatment
After being cooled, the slag is directly conveyed to a slag storage and storage by a closed elevator, the conveying equipment and the slag storage adopt fans for concentrated air draft and are treated by a dust collector to be used as air for a low-temperature section of the grate cooler, and the slag entering a known cement production line is used as a cement raw material.
The application adopts the advanced technologies of suspension preheating and suspension calcination to complete the low-temperature dehydration and pyrolysis of the phosphogypsum in two steps, namely the phosphogypsum not only reduces the fineness of the phosphogypsum through low-temperature drying and grinding, and creates conditions for accelerating the dehydration and desulfurization speed, but also dehydrates natural water and part of crystal water through low-temperature heating in the drying and grinding process, and then removes the crystal water through high-temperature flash combustion to obtain anhydrous gypsum, after the anhydrous gypsum enters a desulfurization and calcination system consisting of a cyclone preheater, a rotary kiln and a cooler, the phosphogypsum is preheated through the cyclone preheater and decomposed in a high-temperature reducing atmosphere in the rotary kiln, and SO is recovered from kiln gas2And the slag is high-CaO slag, which can be used as a calcareous raw material for cement production to replace limestone, or as a basic raw material to be used as building lime, building blocks, low-grade cement and the like. The method separates the phosphogypsum acid-making system from the cement system, comprises phosphogypsum dehydration, phosphogypsum decomposition and resource comprehensive utilization of kiln gas acid-making and kiln slag, can reduce mutual interference of a desulfurization process and a cement process, and can produce high-quality portland cement and high-quality sulfuric acid. The whole system has advanced and reliable equipment, saves capital investment, can realize scientific and comprehensive utilization of energy compared with other kiln types, and has low total energy consumption, high gypsum decomposition rate, large processing capacity and large production scale.
The foregoing is a more detailed description of the invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments disclosed herein. To the utility model belongs to the field of the ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (9)
1. The phosphogypsum desulfurization and calcination treatment system is characterized by comprising a low-temperature dehydration system, a high-temperature calcination system and an acid making system, wherein the low-temperature dehydration system sequentially comprises a dryer, a drying mill and a pipeline furnace, and the high-temperature calcination system sequentially comprises a preheating device, a rotary kiln and a cooler;
the feed inlet of the dryer is connected with the material conveying device, the discharge outlet of the dryer is connected with the feed inlet of the drying mill, the discharge outlet of the drying mill is connected with the feed inlet of the pipeline furnace, the discharge outlet of the pipeline furnace is connected with the air inlet of the preheating device, the air outlet of the preheating device is connected with the acid making system, the discharge outlet of the preheating device is connected with the feed inlet of the rotary kiln, the flue gas outlet of the rotary kiln is connected with the air inlet of the preheating device, and the discharge outlet of the rotary kiln is connected with the feed inlet of the cooler; and the low-temperature water vapor pipeline of the acid making system is connected with the water vapor pipeline inlet of the dryer.
2. The phosphogypsum desulfurization and calcination treatment system according to claim 1, wherein the dryer is a mesh belt dryer, a flue gas outlet of the mesh belt dryer is connected with an air inlet of a bag-type dust remover, purified flue gas is discharged harmlessly through an exhaust fan, and a discharge port of the bag-type dust remover is connected with a feed port of the mesh belt dryer.
3. The phosphogypsum desulfurization and calcination treatment system as claimed in claim 1, wherein the drying mill is provided with a flue gas inlet at the bottom, the flue gas inlet is connected with a fluidized bed furnace, the tube furnace is of a hollow tubular structure, the upper part of the tube furnace is provided with a discharge hole, the lower part of the tube furnace is provided with a feed hole, and the verticality of the tube furnace is not less than 75 degrees.
4. The phosphogypsum desulfurization and calcination treatment system according to claim 1, wherein a cyclone separator is further arranged between the pipeline furnace and the preheating device, a discharge port of the pipeline furnace is connected with an air inlet of the cyclone separator, and an air outlet of the cyclone separator is connected with an air inlet of a dryer.
5. The phosphogypsum desulfurization and calcination treatment system as claimed in claim 1, wherein the preheating device is composed of at least 2 stages of cyclone preheaters which are vertically connected in series, the air outlet of the first stage of cyclone preheater is connected with the acid making system, the air outlet pipeline of the second stage of cyclone preheater is connected with the air inlet pipeline of the first stage of cyclone preheater, the discharge port of the first stage of cyclone preheater is connected with the air inlet pipeline of the second stage of cyclone preheater through a pipeline, and so on, the air inlet pipeline of the last stage of cyclone preheater is connected with the kiln tail flue gas chamber of the rotary kiln, and the discharge port of the last stage of cyclone preheater is connected with the kiln tail feed inlet of the rotary kiln.
6. The phosphogypsum desulfurization and calcination treatment system as claimed in claim 5, wherein the kiln tail flue gas chamber of the rotary kiln is further connected with a reducing agent storage, the kiln head of the rotary kiln is provided with a kiln head cover, a burner is arranged in the kiln head cover and connected with a fuel storage, the lower part of the kiln head cover is connected with a feed port of the cooling machine, the rotary kiln is inclined from a feed end to a discharge end, and the inclination degree is 3-5%.
7. The phosphogypsum desulfurization and calcination treatment system according to claim 1, wherein the lower part of the cooler is provided with a high-temperature section air inlet and a low-temperature section air inlet, and the cooler air outlet is connected with the high-temperature section air inlet of the cooler after passing through the cyclone dust removal device.
8. The phosphogypsum desulfurization and calcination treatment system according to claim 7, wherein the treatment system further comprises a slag storage device, the slag storage device comprises a slag storage warehouse, a feeding port of the slag storage warehouse is connected with a dust remover through an air draft device, and an air outlet of the dust remover is connected with an air inlet of a low-temperature section of a cooler.
9. The phosphogypsum desulfurization and calcination treatment system according to claim 5, wherein an air heat exchanger and a high-temperature dust collector are further arranged between the air outlet of the first-stage cyclone preheater and the acid making system, a flue gas inlet of the air heat exchanger is connected with the air outlet of the first-stage cyclone preheater, a flue gas outlet of the air heat exchanger is connected with a flue gas inlet of the high-temperature dust collector, and a flue gas outlet of the high-temperature dust collector is connected with the acid making system.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142350A (en) * | 2020-09-15 | 2020-12-29 | 长沙中硅环保科技有限公司 | Phosphogypsum desulfurization and calcination treatment system and treatment method |
| CN114772559A (en) * | 2022-05-25 | 2022-07-22 | 武汉理工大学 | Separated dual system and production method for preparing sulfuric acid and co-producing cement from phosphogypsum |
| CN115925295A (en) * | 2022-11-26 | 2023-04-07 | 上海源晗能源技术有限公司 | Comprehensive utilization method of phosphogypsum |
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2020
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112142350A (en) * | 2020-09-15 | 2020-12-29 | 长沙中硅环保科技有限公司 | Phosphogypsum desulfurization and calcination treatment system and treatment method |
| CN112142350B (en) * | 2020-09-15 | 2024-07-19 | 长沙中硅环保科技有限公司 | Phosphogypsum desulfurization calcination treatment system and treatment method |
| CN114772559A (en) * | 2022-05-25 | 2022-07-22 | 武汉理工大学 | Separated dual system and production method for preparing sulfuric acid and co-producing cement from phosphogypsum |
| CN115925295A (en) * | 2022-11-26 | 2023-04-07 | 上海源晗能源技术有限公司 | Comprehensive utilization method of phosphogypsum |
| CN115925295B (en) * | 2022-11-26 | 2024-04-26 | 上海源晗能源技术有限公司 | Phosphogypsum comprehensive utilization method |
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