CN108517387B - Converter gas purification and waste heat recovery system - Google Patents
Converter gas purification and waste heat recovery system Download PDFInfo
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- CN108517387B CN108517387B CN201810510317.8A CN201810510317A CN108517387B CN 108517387 B CN108517387 B CN 108517387B CN 201810510317 A CN201810510317 A CN 201810510317A CN 108517387 B CN108517387 B CN 108517387B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/38—Removal of waste gases or dust
- C21C5/40—Offtakes or separating apparatus for converter waste gases or dust
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
- F27D2017/007—Systems for reclaiming waste heat including regenerators
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Abstract
The invention discloses a converter gas purification and waste heat recovery system, which solves the problems of ineffective utilization of sensible heat, serious iron loss and the like of the existing converter gas. The technical scheme includes that the converter smelting system comprises a converter smelting system and a converter smoke waste heat recovery purification tempering system, the converter smelting system comprises a converter provided with a converter smoke hood and a movable cover skirt and a cold charge preheater positioned above the converter, a discharge port of the cold charge preheater is connected with a feed inlet on the converter smoke hood, a smoke inlet of the cold charge preheater is connected with a smoke outlet on the converter smoke hood through a vaporization cooling flue, and the smoke outlet of the cold charge preheater is connected with the converter smoke waste heat recovery purification tempering system. The system is simple, can effectively recover the sensible heat of the converter smoke dust, improves the recovery amount of coal gas, and can treat high-concentration organic waste liquid and medical waste in a harmless way.
Description
Technical Field
The invention relates to the field of metallurgical energy conservation and environmental protection, in particular to a converter gas purification and waste heat recycling system.
Background
In the converter steelmaking process, carbon in the molten iron generates CO and a small amount of CO at high temperature with the blown oxygen2The mixed gas becomes converter flue gas, and the converter flue gas is called converter gas after being purified. The dust content of the converter smoke is large (80-150 g/m)3The main component of the smoke dust is ferrous oxide accounting for more than 60 percent), the dust content accounts for about 1 to 2 percent of the furnace charge, the temperature is up to 1600 ℃, the smoke dust mainly comprises ferric oxide, and the rest of the smoke dust comprises oxide impurities (such as calcium oxide) and other metal oxides (mainly zinc oxide).
Aiming at the smoke generation mechanism in the converter steelmaking process, the bubble theory and the evaporation theory are adopted by Bixiong and the like to analyze the smoke generation mechanism. It is considered that about 20kg of smoke (mainly including FeO and Fe) is generated per 1t of steel smelted in the steel making process2O3) In the smelting process, due to the characteristics of the process, the iron evaporation at high temperature (evaporation theory) and the oxidized iron entering CO bubbles and being taken out during oxygen blowing (bubble theory) determine that the iron loss cannot be controlled. The generation of the smoke dust not only reduces the yield of molten steel metal, but also increases the burden of a subsequent converter gas purification systemThe load also causes the increase of the steelmaking energy consumption and the treatment cost. Particularly, after the converter flow adopts the molten iron pretreatment and the less slag smelting process, the proportion of iron carried in the slag is reduced, the iron loss caused by smoke dust becomes the largest loss source in the steelmaking process, and 100 plus 150 million tons of ferrite are carried away with the smoke dust per 1 million tons of steel produced.
In order to reduce the generation amount of smoke dust and control the iron loss, Yi Zheng Jiang and the like propose to control the generation of the smoke dust of a converter from the source by applying a COMI (carbon dioxide-oxygen mixed injection steelmaking process) steelmaking process. Its study showed that with CO2The increase of the blowing proportion, the smoke dust and iron loss are continuously reduced, the general trend of the smoke dust amount in the smelting process of the converter is continuously reduced, and the fluctuation of the TFe content is larger. Researchers also think that improving the scrap ratio is a feasible effective measure, because when the scrap is adopted for smelting, the carbon content of a molten pool is extremely low, the carbon-oxygen reaction in the molten pool can be ignored, and the generation of smoke dust is mainly the evaporation and oxidation of iron under the high-temperature condition; when pig iron is adopted for smelting, the carbon content in the pig iron is high, a large amount of CO bubbles generated by carbon-oxygen reaction float upwards, and part of molten iron is gathered on the surfaces of the bubbles and is carried into flue gas to generate a large amount of smoke dust. The said steel-iron powder is used to preheat steel scrap outside furnace, i.e. oxygen-burner is installed on the cover of molten iron tank to heat it, and the ratio of fuel and oxygen is regulated to control reducing atmosphere. By adopting the measure, the converter can feed 20-30 kg/t more steel scrap. Meanwhile, the improvement of the ratio of the steel scrap is also an important way for saving energy of the converter, because the energy value of the steel scrap is only 0.2MJ/kg, and the molten iron is 23.8 MJ/kg.
The dust generation amount can be reduced by increasing the scrap steel ratio, but the dust content of the converter flue gas is large (80-150 g/m)3The main component of the smoke dust is ferrous oxide which accounts for more than 60 percent, the smoke temperature is high (1600 ℃), and the smoke dust contains a large amount of physical heat (about sensible heat brought by the smoke dust generated by ton steel: 0.025GJ, sensible heat brought out by gas produced by ton of steel is about: 0.221GJ), so the converter flue gas must be treated by waste heat recovery, temperature reduction, dust removal and the like before being discharged or entering subsequent users.
At present, three technologies of dry method (LT method), semi-dry method and OG wet method are applied to the treatment of converter flue gas.
The wet OG dust removal process comprises three types of traditional OG wet processes, a tower-text split wet process and a tower type wet process. The domestic iron and steel enterprises adopting the wet OG dust removal process comprise Bao steel Lujing, Zhuhai Yueyofeng, Fangda super steel, Hualing steel, the steel plate, Hebei Tangyin, Nan steel, horse steel and the like. Wet OG dust removal is transformed into a tower-venturi dust removal process by a martensitic steel 2# converter, and the transformation content comprises changing a fixed smoke hood into a movable smoke hood and reducing air entering. The flue gas outlet of the washing tower is connected with the inlet of the washing tower by a water-cooling jacket and water seal combined device. Selecting a double-helix hollow water nozzle, and adopting technologies such as an upstroke adjustable venturi, R.S.V.W circular seam venturi and the like. The primary smoke (dust) dust collecting rate is more than or equal to 99 percent, and no smoke dust overflows above the front fan cover during the violent smelting reaction period. The smoke emission concentration is less than 50mg/m3。
Iron and steel enterprises adopting the dry dedusting process in China include Bao steel, first Steel Caofen Dian, Jiangyin, Densheng, Lingyuan, Tian iron, Guofeng, Shi steel Jingcheng and Ji steel, and the like. Dry dedusting (LT method) is adopted in a converter with 210t steel, smoke is cooled to 800 ℃ through a vaporization cooling flue under the suction of an axial flow fan, and then is further cooled to 240 ℃ through an evaporation cooler; settling about 30-40% of coarse particle dust under the action of water mist, separating the dust from flue gas, and transferring the dust to a coarse ash bin through a coarse ash conveying system; the cooled flue gas enters a cylindrical electrostatic dust collector through a pipeline, and under the action of an electric field, the residual fine dust is collected and transported to a fine dust bin through a fine dust conveying system; through the two times of dust removal, the dust content of the smoke passing through the electric dust remover is 15mg/Nm3The following.
The dry dedusting process has the advantages of saving a large amount of cooling water and sewage treatment equipment, recycling dust into dry powder and avoiding the treatment and pollution of slurry. The dust removal effect is better than that of the OG method, the power consumption is lower than that of the OG method, and the coal gas recovery quality is high. The LT method has the disadvantages of huge equipment investment and high energy consumption; the heat energy of the flue gas at the temperature of 900-1000 ℃ cannot be effectively recycled; the design idea is that plug flow is formed, but actual mixed flow causes two explosion hot points of an evaporative cooler and an electric dust remover, and safety exists; open fire is not completely extinguished in the evaporative cooler, so that in order to ensure evaporative cooling and dust removal effects, the cross section and airflow change in the evaporative cooler and the electric dust remover are large, the mixing process in the container is not fully considered, and the explosion risk is increased; the control detection equipment is complex, and the system maintenance workload is large.
The sensible heat of the flue gas at about 1000 c is not effectively recycled, whether wet or dry. Meanwhile, due to the discontinuity of converter smelting, the discontinuity of converter gas recovery is determined, and the discontinuity of sensible heat recovery further causes the difficult problem of the recovery process.
In order to solve the above problems of the existing converter gas purification and waste heat recovery process, it is urgently needed to develop a converter flue gas purification and collection technology which is safe and stable in operation, efficient in waste heat recovery and utilization and low in investment.
Disclosure of Invention
The invention aims to solve the technical problems and provide a converter gas purification and waste heat recovery system which is simple in system, can effectively recover sensible heat of converter smoke dust, improves the recovery amount of gas, and has the functions of innocent treatment of high-concentration organic waste liquid and medical waste.
The system scheme includes that converter smelting system and converter smoke and dust waste heat recovery purify quenching and tempering system, converter smelting system is including the converter that is equipped with converter petticoat pipe and activity cover skirt and the cold burden pre-heater that is located the converter top, the discharge gate of cold burden pre-heater is connected with the feed inlet on the converter petticoat pipe, the smoke and dust import of cold burden pre-heater is connected through the smoke and dust export on vaporization cooling flue and the converter petticoat pipe, the smoke and dust export connection converter smoke and dust waste heat recovery purifies quenching and tempering system of cold burden pre-heater.
Furthermore, the cold charge preheater comprises one or two or more cold charge preheaters connected in series, the smoke outlet of the former is connected with the smoke inlet of the latter, and the smoke outlet of the last is connected with a converter smoke waste heat recovery purification tempering system.
Further, when the cold charge preheaters are two or more than two in series, the cold charge in the first cold charge preheater is scrap steel, and the cold charge in the second cold charge preheater is at least one of limestone, dolomite or fluorite.
Furthermore, a smoke dust outlet of the vaporization cooling flue is connected with a smoke dust inlet of the cold material preheater through a fluidized bed gasifier, a heat storage chamber or a combustion chamber.
Further, the fluidized bed gasifier is provided with a solid material feeding port and a liquid material spraying port and is used for inputting medical waste or spraying high-concentration organic waste liquid.
Furthermore, the heat storage chamber is connected with a cold material preheater through a cyclone dust collector, or the fluidized bed gasifier is connected with the combustion chamber through the cyclone dust collector, and an ash residue outlet at the bottom of the cyclone dust collector is connected with the fluidized bed gasifier.
Furthermore, the smoke dust outlets of the fluidized bed gasifier and the heat storage chamber are provided with temperature controllers, and the temperature controllers are interlocked with a valve controller of a solid material feeding port or a liquid material spraying port of the fluidized bed gasifier.
Furthermore, a feed inlet is formed in the top of the cold material preheater, a discharge outlet is formed in the bottom of the cold material preheater, a ring-shaped flue is formed in the middle of the cold material preheater, a sealing cover is arranged at the feed inlet, a cavity is formed inside the cold material preheater, a ring-shaped partition plate is arranged on the upper edge of the ring-shaped flue in the cavity, the cavity inside the cold material preheater is divided into two sections by the ring-shaped partition plate, the upper section is a pre-storage section, the lower section is a heating section, a smoke inlet is formed in the lower portion of the heating section, a smoke outlet is.
Furthermore, a discharge hole at the bottom of the fluidized bed gasifier is respectively connected with a feed inlet of the converter smoke hood and a feed inlet of the slag storage tank.
Further, the converter smoke waste heat recovery, purification and conditioning system comprises a gravity dust collector, a waste heat boiler, an electrostatic/bag-type dust collector and a gas fan which are sequentially connected, wherein the gas fan is respectively connected with a gas cabinet and a diffusion tower.
In view of the problems in the background art, the inventor makes the following improvements:
(1) the existing converter smoke waste heat recovery purification tempering system is transformed, a cold charge preheater is connected behind an existing vaporization cooling flue, an OG system adopted by existing smoke wet processing or an evaporation cooling system adopted by smoke dry processing is cancelled, converter smoke coming out of the vaporization cooling flue is introduced into the cold charge preheater and directly exchanges heat with stored converter cold, the temperature of the cold charge entering the converter is increased, and sensible heat of the converter smoke is recovered.
(2) According to the heat balance of converter steelmaking, the cold charge preheaters can be provided with one or more than two cold charge preheaters connected in series, different cold charges are preheated by utilizing a plurality of cold charge preheaters connected in series, the cold charge in the first cold charge preheater is preferably scrap steel, the cold charge in the second and subsequent cold charge preheaters is at least one of steelmaking cold charges such as limestone, dolomite or fluorite, etc. the scrap steel is placed in the first cold charge preheater mainly because ① scrap steel contains organic matters such as oil, grease, etc. which contain sulfur components and need higher temperature to be pyrolyzed, gasified and desulfurized, ② scrap steel has better heat conductivity than far limestone, can quickly reduce the temperature of mixed gas and reduce the system resistance, ③ scrap steel cold charge can tolerate higher temperature without chemical change, and after smoke dust with higher temperature (more than 1000 ℃) is cooled through heat exchange with the scrap steel, the temperature when the smoke dust is subjected to heat exchange with limestone or dolomite can be guaranteed to be lower than the decomposition temperature of the limestone or dolomite, so that the limestone or dolomite is prevented from being heated and decomposed in the cold charge preheaters.
(3) In order to fully utilize the characteristic of strong reducing gas content of converter smoke dust and efficiently utilize the high-temperature sensible heat of the converter smoke dust, a fluidized bed gasifier, a regenerative chamber or a combustion chamber is connected between a vaporization cooling flue and a cold material preheater, and a smoke dust outlet of the vaporization cooling flue is connected with a smoke dust inlet of the cold material preheater through the fluidized bed gasifier, the regenerative chamber or the combustion chamber. The cooling water quantity of the vaporization cooling flue is adjusted, the temperature of the smoke dust entering the fluidized bed gasifier is increased to 1300-1500 ℃, the medical waste introduced into the fluidized bed gasifier or the high-concentration organic waste liquid sprayed into the fluidized bed gasifier is pyrolyzed and gasified to generate coal gas, and meanwhile, the high-temperature smoke dust can thoroughly disinfect and decompose toxic and harmful substances in the medical waste or the organic waste liquid, so that the reduction, harmlessness and recycling of dangerous wastes are realized.
(4) In order to ensure effective and thorough sterilization and disinfection of medical waste or high-concentration organic waste liquid, the temperature of the mixed gas flowing out of the fluidized bed gasifier is controlled to be 800-. In order to prevent the possibly existing mixed gas from being unevenly mixed or the gasification temperature is too low, so that partial mixed gas leaves the fluidized bed gasifier without being sterilized at the high temperature of 800 ℃, a regenerator or a combustion chamber is additionally arranged behind the fluidized bed gasifier, so that the medical waste or high-concentration organic waste liquid is pyrolyzed and gasified at the sufficient smoke temperature, and the mixed gas leaving the fluidized bed gasifier is completely sterilized at the high temperature of about 800 ℃. When the regenerator is arranged, medical waste is not added to the fluidized bed gasifier or organic waste liquid is not sprayed in the initial stage of oxygen blowing smelting, and the waste heat of converter smoke dust is utilized to heat the regenerator to about 1000 ℃ so as to ensure the high-temperature sterilization of subsequent mixed gas.
(5) The mixed gas from the fluidized bed gasifier contains iron-containing dust, tar, carbon residue and the like, and the temperature is controlled to be above 800 ℃, so that the high-temperature sterilization of the mixed gas is ensured, the formation of graphite is effectively controlled, and the blockage of a subsequent system is avoided. And the mixed gas from the fluidized bed gasifier is sent into a subsequent cold material preheater to continuously preheat the cold material, so that the waste heat of the smoke dust is further recycled, and the entrained iron-containing dust, tar, carbon residue and the like are intercepted. After the cold charge is preheated, the temperature of the cold charge entering the converter is increased, the addition amount of the cold charge of the scrap steel can be increased, and the scrap steel ratio is increased. Meanwhile, the intercepted iron-containing dust enters the converter along with the cold burden, so that the iron resource in the converter smoke is recovered, the iron loss per ton of steel is reduced by over 10kg, and the ratio of scrap steel is improved by about 10%.
(6) The medical waste or the high-concentration organic waste liquid enters the fluidized bed gasifier, and is pyrolyzed and gasified by using the smoke dust of the high-temperature converter, so that organic matter resources in the medical waste or the high-concentration organic waste liquid are fully recycled, the gas quantity is increased, oxygen leaked in the process of collecting the smoke dust of the converter is consumed, and the safety of the gas is improved. When the cold charge of the steel scrap is subjected to high-temperature air-separation pretreatment at about 1000 ℃ in a cold charge preheater, organic components such as oil, grease and the like brought in the steel scrap are fully pyrolyzed and gasified, the chemical energy of the organic components is recovered, the content of sulfur brought in the steel scrap entering a furnace is reduced, the secondary smoke generation amount of the steel scrap cold charge entering the furnace is reduced, and explosive smoke pollution during converter steelmaking is thoroughly avoided
(7) The feeding process and the heat exchange process of the cold charge preheater are just consistent with the beat of the converter smelting process, the cold charge in the cold charge preheater is subjected to contact heat exchange in the oxygen blowing smelting stage of the converter smelting process, the feeding process of the cold charge preheater staggers the oxygen blowing smelting stage of the converter smelting, the smoke sensible heat utilization rate is high, the safety is good, the problem of mismatching of process flows does not exist, and the method is particularly suitable for the converter steelmaking process.
(8) The inventor optimally designs the structure of the cold charge preheater, a feed inlet is arranged at the top, a discharge outlet is arranged at the bottom, an annular flue is arranged at the middle part, the steel-making cold charge and mixed gas are in reverse contact heat exchange by adopting a structural form of top feeding and bottom discharging, the heat exchange efficiency is improved, the feed inlet is provided with a sealing cover for sealing the overflow of the mixed gas, the inside of the cold charge preheater is a cavity, the cavity inside the cavity is internally provided with an inverted circular truncated cone-shaped annular baffle plate along the upper edge of the annular flue, the annular baffle plate divides the cavity inside the cold charge preheater into two sections, the upper section is a pre-storage section, the lower section is a heating section, the lower part of the heating section is provided with a smoke inlet, the annular flue area at the upper part of the heating section is provided with a smoke outlet, the mixed gas is collected and discharged by the annular flue after heating the cold charge in the heating section, the inverted circular truncated cone, and a nitrogen inlet is arranged at the lower part of the prestoring section, and nitrogen is introduced for explosion prevention in the processes of feeding to a cold charge preheater and smelting in a converter.
In conclusion, the system is simple, the production and operation cost is low, sensible heat of converter smoke dust is fully utilized to pyrolyze and gasify medical waste or high-concentration organic waste liquid and preheat cold materials, the heat recovered per ton of steel is more than 0.1GJ, the ferrite resource in the converter smoke dust is efficiently recovered, the recovery per ton of steel is more than 10kg, the cost for treating the converter smoke dust is reduced, explosive smoke dust pollution during converter steelmaking feeding is thoroughly avoided, and the safety and stability of the system are improved. Meanwhile, a converter gas purification and recovery system in the steelmaking process is fully utilized to recover and purify pyrolysis gas of medical waste or high-concentration organic waste liquid. Compared with the existing converter gas dust removal process (dry method or wet method), the converter gas dust removal process has the advantages that the net annual production benefit of a steel plant producing 1000 tons of steel is more than 5 million yuan, the annual converter smoke waste heat is recovered by more than 100 million GJ, the annual carbon dioxide emission reduction is about 10 tons, and the annual iron loss reduction (iron recovery) is more than 10 tons.
Drawings
FIG. 1 is a system diagram of embodiment 1 of the present invention;
FIG. 2 is a system diagram according to embodiment 2 of the present invention;
fig. 3 is a system diagram of embodiment 3 of the present invention.
Wherein, 1-converter, 1.1-converter smoke hood, 1.2-movable hood skirt, 2-fluidized bed gasifier, 2.1-solid material feeding inlet, 2.2-liquid material injection inlet, 3-cyclone dust collector, 4-regenerator, 5-combustion chamber, 6-cold material preheater, 6.1-ring flue, 6.2-feeding inlet, 6.3-discharging outlet, 6.4-smoke inlet, 6.5-smoke outlet, 6.6-a nitrogen inlet, 6.7-a prestoring section, 6.8-a heating section, 6.9-a ring-shaped clapboard, 7-a gravity dust collector, 8-a waste heat boiler, 9-a dust collector, 10-a coal gas induced draft fan, 11-a switcher, 12-a diffusing tower, 13-a coal gas cabinet, 14-a vaporization cooling flue, 15-a slag storage tank and 16-a temperature controller.
Detailed Description
Example 1:
referring to fig. 1, the system of the invention comprises a converter smelting system and a converter smoke waste heat recovery, purification and tempering system, wherein the converter smelting system comprises a converter 1 provided with a converter smoke hood 1.1 and a movable hood 1.2 and a cold charge preheater 6 positioned above the converter 1, a discharge port of the cold charge preheater 6 is connected with a feed port on the converter smoke hood 1.1, an air inlet of the cold charge preheater 6 is connected with a smoke outlet on the converter smoke hood 1.1 through a vaporization cooling flue 14, and an air outlet of the cold charge preheater 6 is connected with the converter smoke waste heat recovery, purification and tempering system. In this embodiment, the cold charge preheater includes a cold charge preheater 6, and the charged cold charge is scrap steel.
The cold burden preheater 6 top is established the feed inlet 6.2, the discharge gate 6.3 is established to the bottom, and the ring type flue 6.1 is established to the centre, feed inlet 6.2 is equipped with sealed lid, the inside cavity that is of cold burden preheater 6, the ring type flue 6.9 is arranged along arranging on the ring type flue 6.1 in the cavity, ring type baffle 6.9 divides cold burden preheater internal cavity into two sections, and the upper segment is prestorage section 6.7, and the hypomere is heating section 6.8, heating section 6.8 lower part is established smoke inlet 6.4, and upper portion ring type flue 6.1 region is established smoke outlet 6.5, prestorage section 6.7 lower part is established nitrogen gas import 6.6.
The converter smoke waste heat recovery, purification and conditioning system comprises a gravity dust collector 7, a waste heat boiler 8, an electrostatic/bag-type dust collector 9 and a coal gas fan 10 which are sequentially connected, wherein the coal gas fan 10 is respectively connected with a coal gas cabinet 12 and an emission tower 13 through a switcher 11.
The process comprises the following steps:
the converter smelting process is a periodically repeated process of slag splashing furnace protection, slag pouring, charging, oxygen blowing smelting and tapping water stages, in the oxygen blowing smelting stage, smoke dust generated by the converter 1 smelting is collected by a movable cover skirt 1.2 at the top of the converter 1 and a converter smoke cover 1.1, then is cooled to 1300-1500 ℃ through a vaporization cooling flue 14, and the cooled smoke dust enters a cold material preheater 6 to be in contact heat exchange with a steelmaking cold material (waste steel in the embodiment) stored in the cold material preheater 6, the waste heat of mixed gas is recovered, and meanwhile, iron-containing dust, tar, carbon residue and the like carried in the mixed gas are intercepted. When preheated scrap steel is added into the converter in the next smelting period, the intercepted iron-containing dust, tar, carbon residue and the like are metered and discharged from a discharge port 6.3 of the cold charge preheater 6 along with the scrap steel and then are fed into the converter 1; the smoke dust after heat exchange is discharged from the cold charge preheater 6 and enters the subsequent process of recovering and purifying the waste heat of the smoke dust of the converter.
In the cold charge preheater 6: adding the steel-making cold burden into a heating section 6.8 and a preheating section 6.7 of a cold burden preheater 6 from a feeding hole 6.2, introducing nitrogen into a nitrogen inlet 6.6 in the feeding process for protection, and closing a sealing cover at the feeding hole 6.2 after the feeding is finished; the smoke dust after cooling is introduced from a smoke dust inlet 6.4 at the lower part of the heating section 6.8 to directly exchange heat with the steel-making cold material in the heating section 6.8, and simultaneously carries out heat radiation on the steel-making cold material in the preheating section 6.7, the smoke dust after heat exchange is discharged from a smoke dust outlet 6.5 through an annular flue 6.9, and meanwhile, a nitrogen inlet 6.6 of the preheating section 6.7 introduces nitrogen into the preheating section to form material seal on the material in the preheating section 6.7, so that the smoke dust is ensured to only flow in the heating section 6.8 and fully exchange heat with the cold material in the preheating section 6.8.
The feeding and heat exchange processes of the cold charge preheater 6 are alternately carried out in an intermittent manner, and the feeding process staggers the oxygen blowing smelting stage of the converter smelting process. Namely, in the oxygen blowing smelting stage, the process that the mixed gas continuously enters the cold charge preheater 6 from the smoke dust inlet 6.4 to exchange heat with the scrap steel is called as a heat exchange process, and at the moment, the mixed gas can not be fed into the cold charge preheater 6 but can be synchronously discharged; the cold charge preheater 6 can feed when no mixed gas is introduced for heat exchange (non-oxygen blowing smelting stage), and nitrogen is introduced in the feeding process, and the materials can be synchronously discharged.
In the converter smoke waste heat recovery and purification process: the mixed gas discharged from the cold material preheater 6 is subjected to primary dust removal by a gravity dust remover 7, then is subjected to waste heat recovery by a waste heat boiler 8 and is cooled to 150-plus 200 ℃, is subjected to secondary dust removal by a dust remover 9 and then is pressurized by a gas draught fan 10 and then is sent to a gas tank 13 through a switcher 11 for storage, the redundant gas can be sent to a diffusion tower 12 through the switcher 11 and is discharged, and the discharged gas meets the environmental protection requirement.
Example 2:
referring to fig. 2, the difference from embodiment 1 is: the outlet of the flue gas 14 of the vaporization cooling flue is connected with the air inlet of the cold material preheater 6 through the fluidized bed gasifier 2, the heat storage chamber 4 and the cyclone dust collector 3, and the ash outlet of the cyclone dust collector 3 is connected with the fluidized bed gasifier 2. The material put into the fluidized bed gasifier 2 is medical garbage; the cold material pre-heaters 6 are two in series, the steel-making cold material put into the first cold material pre-heater 6 is scrap steel, and the steel-making cold material put into the second cold material pre-heater 6 is limestone. The rest is the same as example 1.
The fluidized bed gasifier 2 is provided with a solid material feeding port 2.1 and a liquid material spraying port 2.2 and is used for introducing medical waste or high-concentration organic waste liquid, the top of the fluidized bed gasifier 2 is provided with a regenerator 4, and a discharging port at the bottom of the fluidized bed gasifier is respectively connected with a feeding port of a converter smoke hood 1.1 and a feeding port of a slag storage tank 15. The gas outlets of the fluidized bed gasifier 2 and the regenerator 4 are provided with temperature controllers 16, and the temperature controllers 16 are interlocked with valve controllers of a solid material feeding port 2.1 or a liquid material spraying port 2.2 of the fluidized bed gasifier 2.
The process comprises the following steps:
the difference from example 1 is: the smoke dust discharged from the converter 1 is cooled to 1300-; the mixed gas is further sterilized in the heat storage chamber 4, the temperature is controlled to be 800-;
at the initial stage of oxygen blowing smelting, medical waste is not added to the fluidized bed gasifier 2 firstly, smoke dust of the converter 1 directly penetrates through the fluidized bed gasifier 2 to enter the regenerator 4 to heat a heat accumulator, when the temperature of the smoke dust at the outlet of the regenerator 4 reaches 1000 ℃, the medical waste is added to the fluidized bed gasifier 2, when the temperature of the smoke dust at the outlet of the regenerator 4 is lower than 800 ℃, the feeding amount of the medical waste is reduced or the feeding is stopped, and when the temperature of the smoke dust at the outlet of the regenerator reaches 1000 ℃ again, the feeding amount is fed again or increased. That is, when the timing and amount of the medical waste to be fed into the fluidized bed gasifier 2 are controlled, the temperature of the flue dust (or the mixed gas) discharged from the regenerator 4 is firstly ensured to be 800-1000 ℃.
The mixed gas after dust removal is firstly subjected to heat exchange with scrap steel by the first cold material preheater 6 and cooled to below 900 ℃, then is sent into the second cold material preheater 6 to be contacted with limestone for heat exchange and cooled to 250 ℃ of 200-plus-material, and then is discharged from the cold material preheater 6 to enter the subsequent process of recovering and purifying the smoke dust waste heat of the converter. The rest is the same as example 1.
Example 3:
referring to fig. 3, unlike embodiment 2: a regenerative chamber 4 is omitted, the fluidized bed gasifier 2 is connected with a cold material preheater 6 through a cyclone dust collector 3 and a combustion chamber 5, the material which is put into the fluidized bed gasifier 2 through a liquid material injection port 2.2 is high-concentration organic waste liquid, and the steel-making cold material in the cold material preheater 6 is scrap steel. The rest is the same as example 2.
The process is different from that of the example 1: the mixed gas out of the fluidized bed reactor is dedusted by the cyclone deduster 3 and then is fed into the cold material preheater 6 through the combustion chamber 5, and the temperature of the mixed gas entering the cold material preheater 6 is controlled to be 800-1000 ℃. When the combustion chamber 5 is arranged, the converter starts the oxygen blowing smelting stage, and simultaneously, the high-concentration organic waste liquid is added into the fluidized bed gasifier 4 through the liquid material injection port 2.2, the feeding process can be continuously or intermittently carried out, the adding speed of the high-concentration organic waste liquid is controlled, the temperature of mixed gas out of the combustion chamber is ensured to be between 800 and 1000 ℃, when the temperature of the mixed gas is less than 800 ℃, the combustion chamber 5 is started to supplement air, part of the mixed gas is combusted, the temperature of the mixed gas is raised, when the temperature of the mixed gas reaches 1000 ℃, the supplement of the air into the combustion chamber is stopped, and the combustion chamber 5 stops combusting. The rest is the same as example 1.
Claims (8)
1. A converter gas purification and waste heat recovery system comprises a smelting system and a converter smoke waste heat recovery purification tempering system, and is characterized in that the converter smelting system comprises a converter provided with a converter smoke hood and a movable cover skirt and a cold material preheater positioned above the converter, a discharge port of the cold material preheater is connected with a feed port on the converter smoke hood, a smoke inlet of the cold material preheater is connected with a smoke outlet on the converter smoke hood through a vaporization cooling flue, and a smoke outlet of the cold material preheater is connected with the converter smoke waste heat recovery purification tempering system;
the device comprises a cold material preheater, a ring-shaped flue, a sealing cover, a smoke inlet, a discharge outlet, a nitrogen inlet, a smoke inlet, a discharge outlet, a nitrogen outlet and a nitrogen inlet, wherein the top of the cold material preheater is provided with the feed inlet, the bottom of the cold material preheater is provided with the discharge outlet, the ring-shaped flue is arranged in the middle of the cold material preheater, the cavity inside the cold material preheater is a cavity, a ring-shaped partition plate is arranged on the upper edge of the ring-shaped flue in the cavity, the ring-shaped partition plate divides the cavity inside the cold material preheater into two;
the vaporization cooling flue is connected with the smoke inlet of the cold material preheater through the fluidized bed gasifier, the heat storage chamber or the combustion chamber.
2. The system for purifying and recycling the waste heat of converter gas as claimed in claim 1, wherein the cold charge pre-heaters comprise one or two or more cold charge pre-heaters connected in series, the smoke outlet of the previous cold charge pre-heater is connected with the smoke inlet of the next cold charge pre-heater, and the smoke outlet of the last cold charge pre-heater is connected with the system for recovering, purifying and tempering the smoke waste heat of the converter.
3. The system for purifying converter gas and recycling waste heat according to claim 1 or 2, wherein when the number of the cold charge preheaters is two or more than two in series, the cold charge in the first cold charge preheater is scrap steel, and the cold charge in the second cold charge preheater is at least one of limestone, dolomite or fluorite.
4. The system for purifying converter gas and recycling waste heat according to claim 1, wherein the fluidized bed gasifier is provided with a solid material inlet and a liquid material inlet for inputting medical waste or injecting high concentration organic waste liquid.
5. The system for purifying converter gas and recycling waste heat according to claim 4, wherein the regenerator is connected to the cold charge preheater through a cyclone, or the fluidized bed gasifier is connected to the combustion chamber through a cyclone, and an ash outlet at the bottom of the cyclone is connected to the fluidized bed gasifier.
6. The system for purifying converter gas and recycling waste heat according to claim 4 or 5, wherein the gas outlets of the fluidized bed gasifier and the regenerator are provided with temperature controllers, and the temperature controllers are interlocked with valve controllers of a solid material feeding port or a liquid material spraying port of the fluidized bed gasifier.
7. The system for purifying converter gas and recycling waste heat according to claim 4, wherein the discharge hole at the bottom of the fluidized bed gasifier is respectively connected with the feed inlet of the converter hood and the feed inlet of the slag storage tank.
8. The system for purifying and recycling the waste heat of the converter gas according to claim 1, wherein the system for recovering, purifying and conditioning the converter smoke dust and the waste heat comprises a gravity dust collector, a waste heat boiler, an electrostatic/cloth bag dust collector and a gas fan which are connected in sequence, and the gas fan is respectively connected with a gas tank and a diffusion tower.
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| CN111659329B (en) * | 2019-03-07 | 2022-05-24 | 江西福特化工新材料有限公司 | Condensation reaction device |
| CN109971916B (en) * | 2019-04-01 | 2020-04-14 | 东北大学 | Device and method for preheating scrap steel by using converter waste gas |
| CN111575499A (en) * | 2020-06-24 | 2020-08-25 | 易门铜业有限公司 | High-grade matte converting rapid mass and heat transfer system and method thereof |
| CN113025776A (en) * | 2021-02-25 | 2021-06-25 | 北京瑞达宏信科技有限公司 | Converter primary flue gas full-dry dedusting and energy full-recovery system |
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| CN104629808B (en) * | 2015-01-16 | 2017-06-20 | 华中科技大学 | The system that oxygen-enriched combustion boiler low-temperature flue gas produce biomass high heating value gasification gas |
| CN105689360B (en) * | 2016-03-03 | 2017-12-26 | 中冶东方工程技术有限公司 | A kind of system and technique of the domestic garbage burning electricity generation that gasified using coal gas of converter |
| CN206310469U (en) * | 2016-11-22 | 2017-07-07 | 武汉泰康翔科技股份有限公司 | Afterheat of converter gas recycling system |
| CN207175996U (en) * | 2017-07-31 | 2018-04-03 | 安徽盛博冶金环保科技有限公司 | A kind of heater using converter gas waste-heat steel scrap |
| CN107893143B (en) * | 2017-12-18 | 2023-01-13 | 北京京诚泽宇能源环保工程技术有限公司 | Converter gas dry dedusting waste heat recovery system and process |
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