Method for recovering naphthalene, water and tar from coke oven raw gas

Abstract

The application discloses a coke oven raw coal gas de-naphthalene, de-watering and de-tar recovery method, which completely solves the problems of long process route, complex process, large investment, high operation cost, secondary pollution and the like of coking wastewater treatment process route generated in a coking process. The technical scheme comprises the following steps: water vapor formed by water brought by coking coal and water generated by coal pyrolysis enters a bridge pipe through an ascending pipe along with the raw coal gas; non-water-soluble cooling liquid sprayed into the bridge pipe directly cools the raw coal gas; the temperature is reduced to 105-110 DEG C; the raw coal gas is collected into a gas collecting pipe; the raw coal gas is sucked into an electric tar precipitator through a gas fan through a suction pipe, tar droplets are removed, and then the raw coal gas enters a dehumidification tower; the raw coal gas is fluidized, mixed and cooled with powder hygroscopic agents sprayed into the tower; water vapor in the raw coal gas is condensed; the hygroscopic agents absorb the condensed water and adsorb tar, naphthalene and the like in the raw coal gas; and the hygroscopic agents after hygroscopic are directly sent to a cylindrical mixer of a sintering process as sintering raw materials, mixed with other sintering raw materials and granulated. The application has the advantages of simple process, low operation cost and environmental friendliness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metallurgical energy saving and environmental protection, and relates to coke oven gas purification and sintering raw material batching, mixing and granulating production processes, in particular to a coke oven raw gas naphthalene removal, dehydration and tar recovery method. BACKGROUND

[0002] In the existing coking process, the coking coal entering the furnace without coal moisture pretreatment usually contains about 10% moisture, which leaves the coke oven in the form of raw coke oven gas and enters the raw coke oven gas purification and recovery system. The coke oven gas purification and recovery process in China has experienced three stages in general.

[0003] The first stage is from the late 1950s to the mid-1960s. The coke oven gas purification process of the coke plants in China at that time is mainly based on the old process of digesting the saturated plate method for producing ammonium sulfate introduced from the Soviet Union in the 1950s, represented by a batch of large plants such as the Wuhan Iron and Steel Coke Plant, Baotou Steel Coke Plant, Anshan Chemical Plant, Taiyuan Steel Coke Plant and Ma Steel Coke Plant. However, this process has problems such as old process, high energy consumption, imperfect environmental protection measures, low equipment level, etc. The main problems are: the primary cooling uses a vertical pipe cooler, with low cooling efficiency; the ammonium sulfate device is large in size, with large gas resistance, poor product quality and serious equipment corrosion; no desulfurization device is provided, the final cooling system cannot be closed, and the atmosphere and water body are seriously polluted; the steam method is used in the crude benzene distillation system, which not only consumes a large amount of steam, but also cannot guarantee the product quality.

[0004] The second stage is from the mid-1960s to the late 1970s. With the continuous promotion of the 58-type coke oven designed by China and the birth of the 5.5-meter-high carbonization chamber coke oven, the coke oven gas purification process has carried out technical innovation to find the gap with the petroleum and chemical industry. Under the efforts of the majority of technical personnel, during this period, the primary cooling process was changed to two-stage cooling; a variety of oil-washing naphthalene was developed to replace the final cooling water-washing naphthalene; the final cooling water de-cyanide production of yellow prussiate was successfully developed, solving the pollution problem of the final cooling water; solvent de-phenol and biological de-phenol devices were promoted; the pipe furnace de-benzene replaced the steam de-benzene, and a new de-benzene process of double-tower and single-tower was developed; an improved ADA desulfurization device was set up in some coke plants (such as Meishan Coke Plant and Beijing Coke Plant, etc.). In addition, in order to adapt to the situation of tight supply of sulfuric acid at that time, a large number of coke plants using ammonia water process were developed and promoted (such as Jigang, Laigang, Handan Steel, Hanggang, Angang and Pangang, etc.). At that time, the manufacturers producing concentrated ammonia water accounted for one third of the total number of coke plants in China. However, the ammonia water process also has fatal problems such as serious equipment corrosion and blockage, poor quality of concentrated ammonia water products, product oversupply, low operation rate, etc.

[0005] The third stage, since the end of the 1970s, with the construction of Baosteel project, the birth of 6-meter large-capacity coke oven in China, the continuous expansion of the scale of the coking plant, and through the exchange of technology with foreign countries, joint design, technology introduction, etc., a variety of sizes, different processes, multiple sets of devices have been introduced, and the engineering and technical personnel in China have basically mastered the international advanced technologies such as full negative pressure coal gas purification process, AS scrubbing desulfurization process, ammonia decomposition and sulfur recovery process, non-saturator method ammonium sulfate process, FRC and T-H method desulfurization and decyanation process, Solvay process desulfurization process, vacuum carbonate desulfurization process, cold and hot method of Fasam anhydrous ammonia process, and the process of producing concentrated sulfuric acid and 78% sulfuric acid matched with them, and breakthrough progress has been made in the localization of equipment and materials. During this period, Chinese coking technical personnel also developed HPF desulfurization new process, and innovated spray type saturator instead of semi-direct method saturator to produce ammonium sulfate device. With the continuous updating of process technology, the level of production process automation control has also been improved, and DCS distributed computer control technology has been widely applied, so that the coal gas purification technology and equipment in China have made a qualitative leap and moved towards the international advanced level.

[0006] In recent years, with the strengthening of national environmental protection consciousness, the national environmental protection regulations have become increasingly strict, and the requirements for environmental protection have been continuously improved. In order to meet these requirements, the capital investment and operating costs of the coking plant have greatly increased. Under the premise of meeting the user's purified gas index requirements, new processes with short process, high environmental protection level, and low operating cost have been developed, including "HPF wet oxidation desulfurization process using ammonia as alkali source as the center of coal gas purification process", "coal gas purification process using vacuum carbonate desulfurization as the center", "ammonia sulfur recycling washing (AS method) desulfurization as the center of coal gas purification process", etc. However, regardless of the process, the water vapor in the raw coal gas ultimately appears in the form of coking wastewater, enters the wastewater treatment unit for standard treatment or treatment and reuse.

[0007] Due to the presence of a large amount of nitrogen heterocyclic organic matter in coking wastewater, which is difficult to biodegrade, the existing coking wastewater treatment process route is long, the investment is large, and the treatment cost is high. At present, the domestic coking wastewater treatment unit includes: ① physical and chemical pretreatment; ② combined biological treatment; ③ high-efficiency denitrification treatment; ④ advanced oxidation deep treatment; ⑤ membrane separation and reuse, etc., with a treatment cost of about 200 yuan / ton-coke. Although these wastewaters can be recycled and reused, a large amount of secondary pollution is generated in the treatment process, such as VOC emission from the treatment facility, concentrated brine after membrane separation, etc. In order to solve the secondary pollution, additional treatment cost is required.

[0008] In order to reduce the cost of coking wastewater treatment, researchers at home and abroad have carried out a lot of research on the source reduction of wastewater, and developed many coal moisture control technologies, such as Precarbon method, Simcar method, Coaltek method and so on. A few coking plants at home use coal moisture control process (CMC) to control the moisture content between 6-8%. However, the coal moisture control process also has the problem of secondary pollution of coal dust which cannot be overcome. Especially in the process of crushing, mixing, conveying and loading of coking coal, a large amount of dust will be generated due to low moisture content (the lower the moisture content, the more dust), which will have a serious impact on the environment and is one of the main contributors to PM2.5. Despite this, coking wastewater is still generated during the coking process. At the same time, the water vapor condensed from the coke oven raw gas will also absorb a large amount of ammonia in the gas, increasing the cost of ammonia resource recovery in the gas. In summary, the generation of coking wastewater will lead to the following disadvantages: increase the operation cost of coking; reduce the ammonia resource recovery rate in the raw gas; and cause secondary pollution.

[0009] On the other hand, the existing coke oven raw gas purification process still contains a small amount of impurities such as naphthalene and tar vapor. The naphthalene in the gas can precipitate in solid state and block the pipeline; the tar vapor in the gas is harmful to ammonia recovery and crude benzene operation. In order to further remove these impurities in the gas, many end users add a filtration or adsorption unit, which in turn produces secondary pollution such as regeneration treatment of filtration medium or adsorbent.

[0010] Therefore, in the process of coke oven raw gas purification and recovery, a low-carbon, economic and secondary pollution-free gas purification unit needs to be considered to effectively remove and resourceize the moisture, tar mist and naphthalene in the gas. SUMMARY

[0011] The purpose of the present application is to solve the above technical problems, and provide a coke oven raw gas naphthalene removal, dehydration and tar recovery method which is simple in process, energy-saving and consumption-reducing, easy to transform, low in operation cost, secondary pollution-free and friendly to the environment.

[0012] The coke oven raw gas naphthalene removal, dehydration and tar recovery method of the present application comprises that the water vapor formed by the water brought in by the coking coal and the water generated by the pyrolysis of the coal enters the riser through the upper space of the carbonization chamber along with the raw gas, and then flows into the gas collecting pipe through the bridge pipe. The raw gas in the bridge pipe is directly cooled by spraying non-water-soluble cooling liquid, and the temperature is reduced to 105-110℃. Under the suction of the gas fan, the raw gas enters the electric tar precipitator through the suction pipe, removes most of the tar mist, and then enters the dehumidification tower. The water in the gas is condensed and absorbed by the powder hygroscopic agent by fluidization, mixing and cooling with the powder hygroscopic agent sprayed into the tower.

[0013] The dehumidification tower is an empty spray dehumidification tower with an empty interior or a column tube dehumidification tower with heat exchange column tubes arranged in the interior, preferably a column tube dehumidification tower; the column tube dehumidification tower is composed of an upper cylinder and a lower cylinder, the upper cylinder comprises a coal gas upper gas inlet, a coal gas upper gas cavity, a dehumidification tower column tube, a hole plate for mounting and fixing the dehumidification tower column tube, and an upper cylinder flange; the lower cylinder comprises a coal gas lower gas inlet, a gas distribution plate, a dehumidifier spray inlet, a fluidized mixing cavity, a gas-solid fluid outlet, and a lower cylinder flange; the dehumidification tower column tube is located above the fluidized mixing cavity in the lower cylinder; the upper cylinder and the lower cylinder are fixedly and sealingly connected through the upper cylinder flange and the lower cylinder flange.

[0014] The dehumidification process of the coke oven gas containing water vapor in the column tube dehumidification tower is as follows:

[0015] ①The coke oven gas at a temperature of 105-110℃ is divided into two paths, an upper path and a lower path, to enter the column tube dehumidification tower, forming a flow field distribution in which the raw coal gas is first cooled and condensed for dehydration and then heated and warmed, that is, part of the raw coal gas at a temperature of 105-110℃ enters the dehumidification tower column tube from the coal gas upper gas cavity at the top of the column tube dehumidification tower and flows downward into the fluidized mixing cavity; the other part of the raw coal gas at a temperature of 105-110℃ enters the coal gas lower gas cavity from the coal gas lower gas inlet at the bottom of the column tube dehumidification tower and flows into the fluidized mixing cavity through the gas distribution plate;

[0016] ②The powder dehumidifier at a temperature of 40-50℃ is sprayed into the fluidized mixing cavity of the column tube dehumidification tower through a carrier gas;

[0017] ③The two streams of coal gas and the sprayed powder dehumidifier are fluidized and mixed in the fluidized mixing cavity, and physical and chemical reactions such as gas-solid heat exchange, condensation of water vapor in the coal gas, chemical absorption of the condensed water by the dehumidifier, adsorption of toluene and naphthalene, etc. occur, and the temperature of the gas-solid mixture is reduced to 60-70℃;

[0018] ④Under the suction action of the coal gas dust removal fan, the gas-solid mixture flows upward along the gap between the dehumidification tower column tubes, and indirectly exchanges heat with the raw coal gas at a temperature of 105-110℃ in the dehumidification tower column tubes, the temperature of the gas-solid mixed fluid is increased, and the organic components such as light benzene adsorbed by the powder dehumidifier volatilize and return to the coal gas; the temperature of the gas-solid mixed fluid is increased to 70-80℃ and exits the dehumidification tower from the gas-solid fluid outlet into the dust remover, and after dust removal, the concentration of particulate matter in the raw coal gas is reduced by 10 mg / Nm 3 Below.

[0019] ⑤Adjust the proportion of the coal gas entering the upper gas inlet and the lower gas inlet, and adjust the amount of the powder dehumidifier sprayed, to control the temperature of the gas-solid mixed fluid leaving the dehumidification tower to be 70-80℃.

[0020] The powder dehumidifier is calcium oxide powder.

[0021] The powder moisture absorbent is discharged from the bottom of the dust collector, a part of which enters the sintering process, and the remaining part enters the powder screw heat exchanger, and is cooled to 40-50℃ and then recycled into the dehumidification tower; fresh powder moisture absorbent is supplemented before the recycled powder moisture absorbent enters the dehumidification tower.

[0022] A part of the dedusted raw gas is introduced by a pneumatic conveying fan as a carrier gas of the recycled powder moisture absorbent, and the powder moisture absorbent is sprayed into the dehumidification tower.

[0023] The powder moisture absorbent entering the sintering process is used as a flux of one of the sintering raw materials; the flux and other sintering raw materials enter the cylindrical mixer, and are rolled and rubbed under the action of the rotation of the cylindrical mixer to be mixed into balls.

[0024] A differential screw mechanism is arranged in the cylindrical mixer, the differential screw mechanism is composed of at least three screws, the screw includes a screw shaft and non-continuous screw blades; the axis of the screw is parallel to the axis of the mixer cylinder, and the both ends of the screw shaft are fixedly installed on the support beam frame crossing the mixer through bearings, bearing seats and screw fixing frames; the screws are distributed in the form of fan bones in the range of 0.75-0.8π radian of the lower part of the mixer cylinder, are distributed along the longitudinal central axis plane of the circular plane of the two ends of the cylindrical mixer and the two sides thereof, and are arranged staggered along the axis direction of the cylinder body of the cylindrical mixer.

[0025] The flux and other sintering raw materials are sent into the cylindrical mixer through a feeding conveyor belt; the position of the driving drum of the feeding conveyor belt is a material dropping area, and at least one material dropping area screw is arranged at the position away from the longitudinal central axis plane.

[0026] At least two screws are arranged at the position of the longitudinal central axis plane, and the screws at the position of the longitudinal central axis plane are arranged downstream of the material dropping area in the mixer cylinder to avoid the material dropping area.

[0027] When the screw rotates in the cylindrical mixer, the screw blades close to the inner wall of the cylinder are pushed by the accumulated material in the cylinder or the material adhered to the inner wall, so as to drive the screw to rotate and form relative motion with the inner wall of the cylinder body of the cylindrical mixer, thereby generating disturbance to the sintering mixture in the cylindrical mixer and improving the mixing strength.

[0028] A pitch adjuster is arranged in the middle of the screw fixing frame, the length of the screw fixing frame is adjusted through the pitch adjuster, so as to adjust the gap between the screw and the inner wall of the cylinder body of the cylindrical mixer; the multiple screws at the position of the longitudinal central axis plane are periodically adjusted to form different gap values between the screws and the inner wall of the mixer cylinder, the screw blades are pushed by the accumulated material in the cylinder or the material adhered to the inner wall when the cylindrical mixer rotates, different rotation speeds are formed, and the disturbance to the material is strengthened.

[0029] The powder spiral heat exchanger consists of a cylindrical outer shell inclined at a certain angle and fixed on a foundation, a rotating tube array, and a magnetically levitated baffle. The rotating tube array is located inside the shell and is arranged coaxially with the outer shell. The outer shell consists of an upper shell and a lower shell. The upper shell has a powder inlet at the upper part of its lower end, and the lower shell has a powder outlet at the bottom of its upper end. The rotating tube array consists of several parallel metal tubes, an orifice plate for fixing the metal tubes, end caps, heat exchanger spiral blades, and inlet and outlet water short pipes connected to the outlet end orifice plate and end cap. The parallel metal tubes pass through the heat exchanger spiral blades and are welded to the orifice plate to form a spiral conveying mechanism between the rotating tube array and the inner cylinder of the outer shell. The inlet and outlet water short pipes are welded to the end caps or cast as a whole with the end caps. The inlet and outlet water short pipes fixed to the end caps extend out of both ends of the spiral tube cooler outer shell and are fixed on the bearing seats.

[0030] The powder desiccant enters the powder spiral heat exchanger through a powder inlet located at the upper part of the lower end of the upper shell. Under the rotation of the spiral blades of the heat exchanger, it moves obliquely upward and exchanges heat with the cooling medium in the rotating tube. After cooling down, it is discharged from a powder outlet located at the bottom of the upper end of the lower shell. Together with the replenished fresh powder desiccant, it enters the venturi tube and is then injected into the dehumidification tower by carrier gas for circulation.

[0031] To address the problems existing in the background technology, the inventors made the following improvements:

[0032] (1) Cool the raw coke oven gas to 105-110°C above the dew point temperature of water vapor to prevent the raw coke oven gas from cooling down to below the dew point temperature and causing water vapor condensation when passing through the electrostatic precipitator.

[0033] (2) Calcium oxide powder at a temperature of 40-50℃ is sprayed into the dehumidification tower and gasified, mixed and cooled with the incoming raw coal gas, so that the moisture in the coal gas condenses and is absorbed by the calcium oxide powder to generate calcium hydroxide.

[0034] By designing a special structure of the dehumidifier, the raw gas is divided into two ways, the upper and lower, to form a flow field distribution of raw gas cooling and condensation dehydration first and then heating and warming, that is, a part of 105-110℃ raw gas enters the dehumidification tower from the upper gas inlet cavity of the dehumidification tower and flows into the lower gas inlet cavity of the dehumidification tower; another part of 105-110℃ raw gas enters the lower gas inlet cavity of the dehumidification tower from the bottom of the dehumidification tower, and the two streams of gas and the dehumidifier sprayed into the dehumidifier in the fluidized mixing chamber are fluidized, mixed, and subjected to gas-solid heat exchange, water vapor condensation in the gas, chemical absorption of the dehumidifier to the condensed water, adsorption of toluene and naphthalene, and other physical and chemical reactions, and the temperature of the gas-solid mixture is reduced to 60-70℃. Under the suction of the gas dust fan, the gas-solid mixture flows upward along the gap between the dehumidification tower pipes and exchanges heat with the 105-110℃ raw gas in the dehumidification tower pipes, and the temperature rises to 70-80℃. After dust removal, the concentration of particulate matter in the raw gas is reduced by 10mg / Nm 3 The following.

[0035] After calcium oxide powder (quicklime) is digested into slaked lime, it becomes extremely fine slaked lime colloidal particles (the average specific surface area reaches 300000cm 2 / g, which is about 100 times larger than the area before digestion), and the adsorption capacity is enhanced, which can effectively adsorb toluene and naphthalene in the raw gas and improve the purification effect of the gas.

[0036] (3) The generated calcium hydroxide is sent to the sintering process to replace the quicklime in the sintering raw materials.

[0037] According to the material balance, in the steel production process, the quicklime consumed by the sintering ore required for blast furnace smelting can fully meet the demand for moisture absorbent of coking wastewater caused by metallurgical coke.

[0038] Chongqing Iron and Steel and Xiangtan Iron and Steel produce ultra-high basicity sintered ore, and the limestone consumption is 483kg / t of sintered ore and 484kg / t of sintered ore respectively

Chen Tiejun, ed. Modern sintering and agglomeration theory and technology. 2018: 142

[0039] The final amount of CaO in the sintered ore is about 10% (basicity is 1.9-2.0), and the sintering amount is 80.14%, so the amount of quicklime added is: 125kg / t of sintered ore

Xiao Yang, ed. Sintering production technology. 2013: 121

[0040] In the blast furnace charge, according to the coke 380 and sintered ore 1500, the amount of coking wastewater generated by ton of coke:

[0041] ① 140-150kg / t of coke (100kg of water is produced per ton of coal, and 700kg of coke is produced);

[0042] The waste water generated by ton of iron: 53-57kg.

[0043] The amount of lime needed by ton of iron: 125 x 1.5 = 187.5kg

[0044] The amount of water that can be absorbed: 60kg, which is basically balanced with the amount of coking waste water generated.

[0045] The control of coke oven gas dewatering temperature at 60-70℃ (60℃ saturated gas, absolute humidity 129.6g / m 3 , original water content: 268.5g / m 3 ), then the amount of water absorbed: 138.9g / m 3 .

[0046] The amount of water needed by ton of coke: 138.9 x 514 = 71.4kg, converted into ton of iron: 27.1kg, less than half of the lime water absorption capacity (60kg).

[0047] The control of coke oven gas dewatering temperature at 25℃ (absolute humidity 22.8g / m 3 , original water content: 268.5g / m 3 ), then the amount of water absorbed: 245.7g / m 3 .

[0048] The amount of water needed by ton of coke: 245.7 x 514 = 126.3kg, converted into ton of iron: 47.99kg, less than the lime water absorption capacity (60kg).

[0049] Therefore, the amount of lime needed by sinter can fully meet the requirements of coke oven gas dewatering.

[0050] (4) Ingenious design of differential screw mechanism, solve the problem of cylinder mixing machine for sintering mixture mixing granulation process exists in the cylinder stick material.

[0051] The existing barrel sticking problem solution includes optimizing the water adding method, optimizing the batching structure and the cylinder mixer process parameters, optimizing the lining plate and the cylinder internal structure, changing the material falling height, increasing the material scraping and blowing device and adding the material cleaning device, etc.

Peng Yuanfei, Wang Liang. Exploration and practice of reducing mixer sticking. 2015 Third Ironmaking Benchmarking, Energy Saving and Cost Reduction and Related Technology Seminar Proceedings Hebei Metallurgical Society Conference Proceedings; Yang Xie, Shi Yue, Pan Jian, et al. Performance research of Lian Steel four burning cylinder mixer lining plate, sintered pellet. 2019, 44(05): 29-31+56; Shi Zhengbin, Zhao Jianfang, Liang Dong. Solve the problem of secondary mixing machine lining sticking. Shanxi Metallurgy, 2003.(4): 54; Shi Zhengbin, Zhao Jianfang, Liang Dong. Solve the problem of secondary mixing machine lining sticking. Shanxi Metallurgy, 2003.(4): 54

[0052] The differential screw mechanism is arranged in the cylinder mixer, which can completely solve the sticking problem and has the following technical effects:

[0053] ① Strengthen the mixing effect of the mixed material and realize the intelligent control of the sintering mixed material ball size distribution. The running track of the mixed material is complex and changeable through the screw action, which increases the mixing effect; the different spacing values between the multiple screws located in the longitudinal central axis plane and the inner wall of the cylinder mixer are periodically adjusted through the distance adjuster arranged on the screw fixed frame. The screw blades form different rotational speeds under the pushing action of the accumulated material or the sticking material in the cylinder when the cylinder mixer rotates, the disturbance effect of the differential screw mechanism on the material is controlled, and the sintering mixed material ball size distribution required by the cylinder mixer discharge is achieved.

[0054] ② Increase the proportion of large balls in the mixed material. The movement of the mixed material is promoted by the rotation of the screw, the mixed material is moved by the rotation of the mixer, and multiple movements are superimposed. At the same time, through the control of the rotation direction of the screw blades in different screw assemblies, the mixed material is pushed towards the discharge end after entering the discharge area, the rotation direction of the screw blades near the discharge end is adjusted so that the mixed material is pushed towards the feeding end when the screw rotates, the residence time of the material in the cylinder is prolonged, which is beneficial to the rolling of the mixed material with large particle size, and has the interception and retention effect on the mixed material with small particle size, prolongs the residence time of the mixed material with small particle size in the mixer, and is beneficial to the growth of the mixed material with small particle size.

[0055] 3) Solving the problem of cleaning the material adhered to the inner wall of the cylinder mixer. The phenomenon of material adhered to the inner wall of the cylinder mixer is common and serious, which affects the mixing and granulating effect, causes poor particle size of the mixed material, and even causes accidents and shutdown due to too much material adhered. Most enterprises still use the traditional way of regular shutdown and manual cleaning, which not only has high labor intensity, high dust concentration and poor working environment, but also is prone to accidents. Therefore, many enterprises at home and abroad have tried various forms of cleaning devices and measures to prevent material adhesion, but due to the poor internal environment of the cylinder, such as humidity, hard adhesion layer, easy wear of the cleaning device by the mixed material, and easy damage of the cleaning device by the large block adhered to the cylinder wall, a good solution has not been found. After the differential screw mechanism is installed in the cylinder mixer, the distance is adjusted by the distance adjusting device, and the distance is optimized. The more material adhered to the cylinder, the better the rotation of the screw, and the better the cleaning effect. At the same time, multiple screws are arranged along the central axis of the cylinder body in staggered manner, covering the middle area and the feeding area of the inner wall of the cylinder, so that the inner wall of the cylinder is cleaned without dead angle.

[0056] 4) Reducing the manufacturing cost of the cylinder mixer, and the inner wall can not be provided with an inner lining. A fixed adhesion layer is formed on the inner wall of the cylinder body by utilizing the adhesion property of the material, which serves as the inner lining of the cylinder body. The distance between the screw and the inner wall of the cylinder body is adjusted to maintain the thickness of the adhesion layer, form a fixed-thickness adhesion layer, protect the inner wall of the cylinder body, reduce the wear of the inner wall of the cylinder body, and effectively save investment and operation cost.

[0057] 5) Recycling the waste heat of the powder screw heat exchanger system and the sensible heat of the hot powder moisture absorbent directly recovered from the sintering ingredients.

[0058] The powder moisture absorbent captured by the dust collector enters the powder screw heat exchanger from the lower end of the hot powder inlet of the powder screw heat exchanger. As the cooling pipes of the heat exchanger rotate, the screw blades of the heat exchanger push the powder moisture absorbent upwards, covering the entire cooling pipe of the heat exchanger. The powder moisture absorbent is filled in the entire cylindrical cavity surrounded by the upper and lower shells of the heat exchanger, which has large heat exchange area and high heat exchange efficiency.

[0059] In the powder screw heat exchanger, a magnetic suspension baffle is ingeniously designed to replace the traditional inclined rotary body stop wheel device, solving the wear and noise problems of the traditional stop wheel control. The electromagnetic force generated by the magnetic suspension device is used to balance the downward sliding force of the rotating body containing the cooling pipe of the heat exchanger.

[0060] Advantages:

[0061] 1) Solving the pollution problem of coking wastewater. The raw material for sintering production, i.e. quicklime, is used as the moisture absorbent of raw gas, which absorbs all the condensed water in the cooling temperature range of raw gas.

[0062] 2) Improved coke oven gas quality, reduced tar, naphthalene content in the gas. Using the strong adsorption performance of quicklime after water absorption and digestion, trace impurities such as tar mist and naphthalene in raw gas are effectively adsorbed, and the tar content in the purified gas can be reduced to 5mg / Nm 3 The following.

[0063] 3) Recovered the waste heat of raw gas. Using the combination of powder hygroscopic agent and powder screw heat exchanger, the sensible heat in the temperature range of raw gas cooling and cooling is effectively recovered.

[0064] 4) Improved the clean production level of the coking process. Since no coking wastewater is generated, VOC emissions from the wastewater treatment unit are avoided, and the powder hygroscopic agent also adsorbs harmful components such as benzopyrene, which is finally oxidized and decomposed in the sintering process.

[0065] 5) Increased the proportion of large balls in the sintering mixture and improved the permeability of the sintering material layer. The differential screw mechanism delays the mixing process of the sintering raw materials, especially the selective delay effect of small particle mixtures, which increases the balling time of small particle mixtures and increases the proportion of larger particle mixtures, with a proportion of 3-8mm particle size mixtures of more than 65%, improving the permeability of the sintering material layer; The problem of material adhesion to the inner wall of the cylindrical mixer is solved. By adjusting the gap between the screw and the inner wall of the mixer in the differential screw mechanism, the differential between the screw and the cylinder of the mixer, the adhesion to the inner wall is cleaned and the mixing of the material is strengthened.

[0066] 6) Strengthen the mixing effect of the mixture and realize intelligent control of the particle size distribution of the material balls. Change the running track of the mixture, make the running track of the mixture complex and changeable through the action of the screw, increase the mixing effect; By setting the distance adjuster on the screw fixed frame and the pressure and torsional moment sensor, according to the periodic adjustment of the torsional moment value, a plurality of screws located in the vertical direction of the center axis of the cylinder form different gap values between the inner wall of the cylinder, the screw blades are pushed by the accumulated material or the material adhered to the inner wall of the cylinder when the cylinder mixer rotates, forming different rotation speeds, controlling the disturbance effect of the differential screw mechanism on the material, so that the cylinder mixer discharge reaches the required particle size distribution of the mixed material balls. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The process flow diagram of the present invention uses a tube type dehumidification tower.

[0068] Figure 2 The process flow diagram of the present invention uses an air injection type dehumidification tower.

[0069] 1-column type dehumidification tower; 2-empty spray type dehumidification tower; 1-1: coal gas upper inlet cavity; 1-2: coal gas lower inlet cavity; 1-3: coal gas upper inlet; 1-4: coal gas lower inlet; 1-5: orifice plate; 1-6: gas distribution plate; 1-7: lower cylinder flange; 1-8: upper cylinder flange; 1-9: dehumidification tower column; 1-10: dehumidifier spray inlet; 1-10A: dehumidifier inlet; 1-11: gas-solid fluid outlet; 1-12: fluidized mixing cavity; 3-dust collector; 4-powder screw heat exchanger; 4-1: heat exchanger upper shell; 4-2: heat exchanger lower shell; 4-3: heat exchanger screw blade; 4-4: heat exchanger cooling column; 4-5: hot powder inlet; 4-6: cold powder outlet; 4-7: water inlet end orifice plate head; 4-8: water outlet end orifice plate head; 4-9: magnetic suspension baffle; 5-venturi; 6-pneumatic conveying fan; 7-sintering bin; 8-cylinder mixer; 9-screw fixing frame; 9-1: axial support beam; 9-2: transverse support beam; 9-3: mixer outer support column; 10-differential screw mechanism; 10-1: screw assembly; 10-2: screw mounting frame; 10-3: screw blade; 10-4: screw mandrel; 10-5: bearing; 10-5: distance adjuster; 11-sintering machine; 12-feeding conveyor belt; 12-1: driving roller; 12-2: belt; 12-3: driven roller; 13-coke oven; 13-1: carbonization chamber; 13-2: riser; 13-3: oven column; 13-4: coal charging hole; 14-nozzle; 15-regulating valve; 16-cooling liquid pipe; 17-bridge pipe; 18-electric precipitator; 19-coal gas fan; 20-suction pipe; 21-gas collecting pipe; 22-tar box; 23-coal gas dust removal fan.

[0070] α-vertical central axis, β-charge point. DETAILED DESCRIPTION

[0071] The application will be further explained in conjunction with the accompanying drawings:

[0072] Example 1:

[0073] Referring to Figure 1 , the coke oven raw coal gas naphthalene removal, dehydration and tar recovery method of the application includes that the water vapor formed by the water content of coking coal and the water content generated by coal pyrolysis enters the riser 13-2 through the upper space of the carbonization chamber 13-1 along with the raw coal gas, and then is collected into the gas collecting pipe 21 through the bridge pipe 17.

[0074] The non-water soluble cooling liquid is injected into the bridge pipe 17 to directly cool the raw coal gas, and the temperature is reduced to 105-110°C. Under the suction of the gas fan 19, most of the tar mist drops are removed in the electric tar precipitator 18, and then the raw coal gas enters the tube type dehumidifying tower 1. The raw coal gas is fluidized, mixed and cooled with the powder dehumidifier injected into the tower, the moisture in the raw coal gas is condensed and absorbed by the powder dehumidifier. The powder dehumidifier absorbs the condensed water in the raw coal gas at the same time, and also adsorbs the tar mist drops and naphthalene in the raw coal gas.

[0075] The raw coal gas enters the tube type dehumidifying tower 1 in two parts. One part enters the gas upper inlet chamber 1-1 from the gas upper inlet 1-3 at the upper part of the tube type dehumidifying tower 1, and then enters the dehumidifying tower tube 1-9 through the orifice plate 1-5 to flow into the fluidized mixing chamber 1-12. The other part enters the gas lower inlet chamber 1-2 from the gas lower inlet 1-4 at the bottom of the tube type dehumidifying tower 1, and then flows into the fluidized mixing chamber 1-12.

[0076] The powder dehumidifier, i.e. calcium oxide powder with a temperature of 40-50°C, is injected into the fluidized mixing chamber 1-12 of the tube type dehumidifying tower 1 through the Venturi tube 5 by gas force. The two streams of gas and the calcium oxide powder are fluidized, mixed, and subjected to gas-solid heat exchange, water vapor condensation, chemical absorption of the condensed water by the calcium oxide powder, adsorption of the tar mist and naphthalene, and other physical and chemical reactions in the fluidized mixing chamber 1-12. The temperature of the gas-solid mixture is reduced to 60-70°C. Under the suction of the gas de-dusting fan 23, the gas-solid mixture flows upward along the gap between the dehumidifying tower tubes 1-9 in the tube type dehumidifying tower 1, exchanges heat with the 105-110°C raw coal gas in the dehumidifying tower tubes 1-9, and adjusts the proportion of the gas entering from the gas upper inlet 1-3 and the gas lower inlet 1-4, and adjusts the injection amount of the calcium oxide powder to control the temperature of the gas-solid mixture leaving the tube type dehumidifying tower 1 to be 70-80°C.

[0077] The gas-solid mixture with a temperature of 70-80°C leaves the tube type dehumidifying tower 1 from the gas-solid fluid outlet 1-11 and enters the dust collector 3. After dust removal, the concentration of particulate matter in the raw coal gas is reduced by 10 mg / Nm 3

[0078] A part of the raw coal gas after dust removal enters the subsequent coal gas purification system, and the other part is introduced as the carrier gas of the powder dehumidifier, i.e. calcium oxide powder, by the gas force conveying fan 6 to suck the calcium oxide powder from the Venturi tube 5 and send it into the tube type dehumidifying tower 1.

[0079] After absorbing moisture, the calcium oxide powder is digested into slaked lime, which is extremely fine slaked lime colloidal particles (the average specific surface area is 300000 cm 2 / g, which is about 100 times larger than the area before digestion), and the adsorption capacity is enhanced, which can effectively adsorb the tar mist and naphthalene in the raw coal gas and improve the purification effect of the coal gas.​

[0080] The calcium hydroxide and calcium oxide mixed powder generated after hygroscopic digestion is captured by the dust collector 3 and then divided into two parts. One part is sent to the sintering process to replace the quicklime in the sintering raw materials, and the other part enters the space surrounded by the upper shell 4-1 and the lower shell 4-2 of the powder screw heat exchanger 4 from the hot powder inlet 4-5 of the powder screw heat exchanger 4, and exchanges heat with the heat exchanger cooling pipe 4-4. Under the push of the heat exchanger screw blade 4-3, the calcium hydroxide powder in the powder screw heat exchanger 4 is stirred and pushed upward by the heat exchanger screw blade 4-3, and then discharged from the cold powder outlet 4-6 into the text tube 5, and then introduced into the column pipe type dehumidification tower 1 by the carrier gas for recycling. At the same time, fresh calcium oxide powder is supplemented into the text tube 5.

[0081] In order to ensure the stable rotation of the heat exchanger cooling pipe 4-4 in the powder screw heat exchanger 4, a magnetic suspension baffle is used instead of the traditional inclined installation of the rotary body to solve the wear and noise problems of the traditional baffle control. The present application creatively uses electromagnetic force generated by a magnetic suspension device to balance the downward sliding force of the rotating body containing the heat exchanger cooling pipe.

[0082] The structure of the powder screw heat exchanger 4 in this embodiment is described in detail in the prior application with the application number 202010667081.6 and the invention name "a powder material screw heat exchanger".

[0083] The calcium hydroxide and calcium oxide mixed powder generated after hygroscopic digestion and captured by the dust collector 3 is sent to the sintering process and mixed with other sintering raw materials through the feeding conveyor belt 12 into the cylindrical mixer 8. Under the rotation of the cylindrical mixer 8, the sintering mixture rolls and rubs in the cylinder to form balls, and finally enters the sintering machine 11 to be sintered into ore. The tar, naphthalene and other substances adsorbed by the dehumidifier participate in sintering.

[0084] A differential screw mechanism 10 is arranged in the cylindrical mixer 8 to clean the adhering material on the inner wall of the cylindrical mixer 8 in real time.

[0085] The differential screw mechanism 10 is composed of at least three screw assemblies 10-1, which include a screw shaft 10-4 and non-continuous screw blades 10-3. The axis of the screw shaft 10-4 is parallel to the axis of the cylinder body of the cylindrical mixer 1, and the two ends of the screw shaft 10-4 are fixed on the axial support beam 9-1 of the screw fixing frame 9 transversely arranged in the cylindrical mixer 8 through bearings 10-5 and screw fixing frames 10-2. The axial support beam 9-1 is arranged symmetrically with respect to the longitudinal central axis plane α of the circular plane of the cylindrical mixer 8 and parallel to the central axis of the cylinder body of the cylindrical mixer 1.

[0086] Spiral mounting frame 9 is composed of axial support beam 9-1 and transverse support beam 9-2 in the same plane, which are welded or bolted together, and cross the two ends of the cylinder body of cylinder mixer 8 along the axis of the cylinder body of cylinder mixer 8, and are fixed on the four external support columns 9-3 outside the cylinder mixer 8.

[0087] Spiral mounting frame 10-2 is composed of two sections, which are rigidly connected by distance adjuster 10-5, one end of which is connected to spiral assembly 10-1, and the other end is rigidly connected to axial support beam 9-1.

[0088] Spiral assembly 10-1 is distributed in the form of a fan-shaped bone in the range of 0.75-0.8π radians at the lower part of the cylinder body of cylinder mixer 8, along the longitudinal center axis plane α of the circular plane of the two ends of the cylinder body of cylinder mixer 8 (including the position of the longitudinal center axis plane α), and is arranged in a staggered manner along the axial direction of the cylinder body of cylinder mixer 8; at least two spiral assemblies 10-1 are provided at the position of the longitudinal center axis plane α.

[0089] The spiral assembly 10-1 at the position of the longitudinal center axis plane α is arranged downstream of the material dropping area β in the cylinder body of cylinder mixer 1, avoiding the dropping point; at least one spiral assembly 10-1 is provided at the position of the longitudinal center axis plane α away from the dropping area β.

[0090] When multiple spiral assemblies 10-1 are located at the position of the longitudinal center axis plane α, these spiral assemblies 10-1 are arranged in sequence along the overall direction of material movement, and the spiral blade 10-3 at the most upstream position has a rotation direction opposite to that of the other spiral blades 10-3 downstream thereof.

[0091] The sintered mixture is fed into the dropping area β of cylinder mixer 8 through the feeding conveyor 12, and as the cylinder mixer 8 rotates, the mixture is lifted to a height exceeding the angle of repose of the material and rolls downward along the inner wall of the cylinder mixer 8 towards the discharge direction, the material adhering to the inner wall of the cylinder mixer 8 continues to move upward along the inner wall of the cylinder body, and meets the spiral assembly 10-1 installed at the position of the longitudinal center axis plane α away from the dropping area β, which pushes the spiral blade 10-3 and rotates the spiral assembly 10-1, at the same time, the spiral blade 10-3 cuts into the adhering material layer and rotates, and the spiral blade 10-3 cuts off the adhering material.

[0092] Spiral assembly 10-1 is distributed in the form of a fan-shaped bone in the range of 0.75-0.8π radians at the lower part of the cylinder body of cylinder mixer 8, along the longitudinal center axis plane α of the circular plane of the two ends of the cylinder body of cylinder mixer 8 (including the position of the longitudinal center axis plane α), and is arranged in a staggered manner along the axial direction of the cylinder body of cylinder mixer 8; at least two spiral assemblies 10-1 are provided at the position of the longitudinal center axis plane α.

[0093] Example 2:

[0094] Referring to Figure 2 The coke oven raw gas denaphthalene, dewatering and de-tar recovery method of the present application, including the water vapor formed by the water content of coking coal and the water content generated by coal pyrolysis, entering the riser 13-2 through the upper space of the carbonization chamber 13-1 along with the raw gas, and then entering the gas collecting pipe 21 through the bridge pipe 17.

[0095] The non-water-soluble cooling liquid is sprayed into the bridge pipe 17 to directly cool the raw gas, and the temperature is reduced to 105-110°C. Under the suction of the gas fan 19, the raw gas enters the electric tar precipitator 18 through the suction pipe 20 to remove most of the tar droplets, and then enters the air-blast type dehumidification tower 2 from the bottom gas inlet 1-4 of the air-blast type dehumidification tower 2 through the gas distribution plate 1-6.

[0096] The powder dehumidifier - calcium oxide powder with a temperature of 40-50°C is pneumatically conveyed to the air-blast type dehumidification tower 2 through the Venturi pipe 5 by the carrier gas, and is sprayed into the tower from the dehumidifier spray inlet 1-10, and is fluidized and mixed with the raw gas. The gas-solid mixture is cooled, the water vapor in the gas is condensed, the calcium oxide powder chemically absorbs the condensed water, and the physical and chemical reactions such as adsorption of tar mist and naphthalene occur. The temperature of the gas-solid mixture is reduced to 70-80°C. Under the suction of the gas dust removal fan 23, the gas-solid mixture exits the air-blast type dehumidification tower 2 from the gas-solid fluid outlet 1-11 and enters the dust collector 3. After dust removal, the concentration of particulate matter in the raw gas is reduced by 10 mg / Nm 3 The following.

[0097] The mixed powder of calcium hydroxide and calcium oxide generated after dehumidification and digestion is collected by the dust collector 3, and is divided into three parts. One part is sent to the sintering process to replace the quicklime in the sintering raw materials; one part directly enters the tower from the dehumidifier inlet 1-10A at the top of the air-blast type dehumidification tower 2; and the remaining part enters the powder screw heat exchanger 4 for cooling of the dehumidifier and recovery of waste heat.

[0098] The rest is the same as example 1.

Claims

1. A method for recovering naphthalene, water and tar from coke oven raw gas, comprising that the water vapor formed by the water brought in with coking coal and the water generated by the pyrolysis of coal enters the riser through the space above the coking chamber, and then flows into the gas collecting pipe through the bridge pipe, characterized in that, The non-water-soluble cooling liquid sprayed into the bridge pipe directly cools the gas to a temperature of 105-110 DEG C, and the gas is sucked into the electric tar precipitator by the gas fan and then into the dehumidification tower to be fluidized and mixed with the powder desiccant sprayed into the tower, so that the moisture in the gas is condensed and absorbed by the powder desiccant; The dehumidification tower is an empty spray type dehumidification tower with an empty interior, or a column type dehumidification tower with heat exchange column pipes arranged in the interior; the column type dehumidification tower is composed of an upper cylinder and a lower cylinder, the upper cylinder comprises a gas inlet, a gas inlet cavity, column pipes, a perforated plate for fixing the column pipes, and a flange, the lower cylinder comprises a gas inlet, a gas distribution plate, a desiccant inlet, a fluidization and mixing cavity, a gas-solid fluid outlet, and a flange, the column pipes are arranged above the fluidization and mixing cavity in the lower cylinder, and the upper cylinder is fixedly and sealingly connected with the lower cylinder through the flanges; The dehumidification process in the column type dehumidification tower is as follows: ① The coke oven gas at a temperature of 105-110 DEG C is divided into two parts and introduced into the column type dehumidification tower, so that the gas is cooled and condensed to remove water and then heated to increase the temperature, i.e. a part of the gas at a temperature of 105-110 DEG C is introduced into the column pipes from the gas inlet cavity at the top of the column type dehumidification tower and then flows downward into the fluidization and mixing cavity, and the other part of the gas at a temperature of 105-110 DEG C is introduced into the gas inlet cavity from the gas inlet at the bottom of the column type dehumidification tower and then flows into the fluidization and mixing cavity through the gas distribution plate; ② The powder desiccant at a temperature of 40-50 DEG C is sprayed into the fluidization and mixing cavity in the dehumidification tower through a carrier gas; ③ The two gas streams and the sprayed powder desiccant are fluidized and mixed in the fluidization and mixing cavity, so that gas-solid heat exchange occurs, water vapor in the gas is condensed, the powder desiccant chemically absorbs the condensed water, and physical and chemical reactions of the powder desiccant absorbing the tar mist and naphthalene occur, and the temperature of the gas-solid mixture is reduced to 60-70 DEG C; ④Under the suction of the coal gas dedusting fan, the gas-solid mixture flows upward along the gap between the dehumidification tower pipes and indirectly exchanges heat with the 105-110℃ raw coal gas in the dehumidification tower pipes, the temperature of the gas-solid mixture is raised, the light organic components of the benzene adsorbed by the powder hygroscopic agent are volatilized and returned into the coal gas; the temperature of the gas-solid mixture is raised to 70-80℃ and the gas-solid mixture flows out of the dehumidification tower into the dust collector, after being dedusted, the concentration of the particulate matters in the raw coal gas is reduced by 10mg / Nm 3 The following; ⑤ The proportions of the gas introduced from the upper gas inlet and the lower gas inlet are adjusted, and the amount of the powder desiccant sprayed is adjusted, so that the temperature of the gas-solid mixture flowing out of the dehumidification tower is controlled to be 70-80 DEG C.

2. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method according to claim 1, characterized in that, The powder desiccant is calcium oxide powder.

3. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 1, characterized in that, The powder desiccant is discharged from the dust collector, a part of which is introduced into a sintering process, and the remaining part is introduced into a powder screw heat exchanger, cooled to 40-50 DEG C, and then recycled into the dehumidification tower; fresh powder desiccant is added to the recycled powder desiccant before the powder desiccant is introduced into the dehumidification tower.

4. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 1, characterized in that, A part of the dust-removed coke oven gas is introduced as a carrier gas for the powder desiccant by a pneumatic conveying fan, and the powder desiccant is sprayed into the dehumidification tower.

5. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 3, characterized in that, The powder desiccant introduced into the sintering process is used as a flux for sintering raw materials, and the flux and other sintering raw materials are introduced into a cylindrical mixer and mixed into balls under the rolling and rubbing action of the rotating cylindrical mixer.

6. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 5, characterized in that, The differential screw mechanism is composed of at least three screws, which include screw shafts and discontinuous screw blades. The screw axis is parallel to the axis of the mixing machine cylinder. The screw shafts are fixed on the support beam of the mixing machine through bearings, bearing seats and screw fixing frames. The screws are distributed in the form of fan bones in the range of 0.75-0.8π radian of the lower part of the mixing machine cylinder, along the longitudinal central axis plane of the two end circular planes of the mixing machine cylinder and on both sides thereof, and are arranged staggeredly along the axis direction of the mixing machine cylinder. The flux and other sintering raw materials are fed into the mixing machine through the feeding conveyor belt. The position of the driving roller of the feeding conveyor belt is the dropping area, and at least one screw is arranged in the dropping area away from the longitudinal central axis plane. The screw is arranged downstream of the dropping area in the mixing machine cylinder and avoids the dropping area. When the mixing machine cylinder rotates, the screw blades close to the inner wall of the cylinder are pushed by the accumulated materials or the materials adhered to the inner wall, so as to drive the screw to rotate and form relative motion with the inner wall of the mixing machine cylinder, thereby disturbing the sintering mixture in the mixing machine cylinder and improving the mixing strength.

7. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 6, characterized in that, The middle part of the screw fixing frame is provided with a distance adjuster, which adjusts the length of the screw fixing frame, so as to adjust the gap between the screw and the inner wall of the mixing machine cylinder. The distance adjuster adjusts the distance between the longitudinal central axis plane and the inner wall of the mixing machine cylinder periodically, so that the screw blades form different rotation speeds when the mixing machine cylinder rotates, thereby intensifying the disturbance to the materials.

8. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 6, characterized in that, The powder screw heat exchanger is composed of a cylindrical shell fixed on a foundation at a certain angle, rotating pipe and magnetic suspension baffle. The rotating pipe is coaxially arranged in the shell. The shell is composed of an upper shell and a lower shell. The powder inlet is arranged at the upper end of the lower shell. The rotating pipe is composed of a plurality of parallel metal pipes, a hole plate for fixing the metal pipe, a head, a heat exchanger screw blade and a water inlet and outlet short pipe connected by the hole plate head. The parallel metal pipes are welded with the hole plate and the heat exchanger screw blade, forming a screw conveying mechanism between the rotating pipe and the inner cylinder of the shell. The water inlet and outlet short pipe is welded on the head or integrally formed with the head. The water inlet and outlet short pipe fixed on the head extends out of the shell of the powder screw heat exchanger and is fixed on the bearing seat.

9. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 3, characterized in that, The powder hygroscopic agent enters the powder screw heat exchanger from the powder inlet arranged at the upper end of the lower shell, moves obliquely upward under the rotation of the heat exchanger screw blade, exchanges heat with the cooling medium in the rotating pipe, is cooled and discharged from the powder outlet arranged at the bottom of the upper end of the lower shell, and enters the textine pipe together with the fresh powder hygroscopic agent, and is sprayed into the dehumidification tower through the carrier gas for circulation.

10. The coke oven raw gas denaphthalized, dewatered and de-tarred recovery method as claimed in claim 3, characterized in that, ​

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