CN113975919B - Dry-method chlorine component recovery process based on synergistic treatment of chlorine-containing solid wastes by cement kiln - Google Patents

Abstract

The invention discloses a dry-method chlorine component recovery process for cooperatively treating chlorine-containing solid waste based on a cement kiln, which solves the problems of long process, high energy consumption, high equipment investment and operation cost and environmental pollution in the conventional wet-method chlorine-containing component treatment. The technical scheme includes that solid waste containing chlorine components enters a cement production line, the chlorine components are gasified and enter flue gas under the high-temperature environment in a rotary kiln, part of the flue gas is led out from a kiln head flue gas hood of the rotary kiln, the led-out part of the flue gas is sent into a cooling tower after being dedusted by a dry method to directly exchange heat with potassium chloride powder materials for cooling, the chlorine components in the flue gas are condensed and enter the potassium chloride powder materials, the flue gas after heat exchange is discharged from the top of the cooling tower, and the potassium chloride powder materials after heat exchange are discharged from the bottom of the cooling tower. The method has the advantages of simple process, low investment cost and operation cost, environmental friendliness, energy conservation, consumption reduction and effective recovery of potassium chloride products.

Description

Chlorine component dry recovery process based on cement kiln co-processing chlorine-containing solid waste

technical field

The invention belongs to the field of solid waste treatment, and relates to a resource recovery process of potassium chloride when cement kilns co-process chlorine-containing solid waste, specifically a dry recovery method for chlorine components based on cement kiln co-processing chlorine-containing solid waste craft.

Background technique

In the "Industrial Structure Adjustment Catalog" revised and released by the National Development and Reform Commission in 2019, the co-processing of fly ash in cement kilns is listed as the first item in the building materials encouragement category. Fly ash comes from municipal waste incineration power plants, and is a typical hazardous waste containing chlorine components (potassium chloride + sodium chloride), with a chlorine content of 10% or even higher [Zhang Lei, Zhang Yunze. Separation of sodium and potassium salts in The application of fly ash cement kiln co-processing line. Salt Science and Chemical Industry, 2017, 46(10): 38-40], also contains a large amount of dioxins and heavy metals, and its production volume is nearly 10 million tons per year.

The cement kiln has the characteristics of high temperature, large heat capacity and thermal inertia, long residence time in the high-temperature area of logistics, and thorough decomposition of harmful components. Using cement kilns to co-process solid waste such as domestic garbage and fly ash has become the mainstream development direction of urban solid waste disposal . According to the production site tracking analysis of solid waste co-processing in cement kilns [Li Guoqiang, Han Tao, Xiao Yandang, et al. Research on Cement Kiln Bypass Ventilation Technology. Cement Technology, 2012.6:29-32], potassium, The high content of sodium, chlorine, and sulfur will bring serious consequences to the stable operation of the cement production line system, especially in the kiln tail smoke chamber, feeding slope, shrinkage, and the cone of the lowest cyclone. Skin clogging, in severe cases, will affect the stability and normal operation of the firing system. That is to say, on the cement production line, the area at 800-900 ° C is prone to skin blockage.

Theoretically, the melting points of crystals such as KCl, NaCl, and _CaCl2 are 770°C, 801°C, and 772°C, respectively, and the boiling points are 1420°C, 1465°C, and 1935°C, respectively, so theoretically, these chlorine-containing compounds must be heated to at least 1400°C The above can be gasified. However, since the cement raw material is a mixture of various inorganic salt compounds, theoretically, these salt mixtures will form eutectic components, and the gasification temperature will also decrease. According to the analysis of crust clogging in actual production, the boiling point of the mixed salts containing chlorine components should be at 800-900°C. Therefore, in the process of cement production, the chlorine-containing components will gasify at high temperature, condense down at 800-900°C, and enter the high-temperature zone of the cement production unit again with the cement raw materials, thus forming the chlorine-containing components in the cement. Circular enrichment within a production unit.

Li Ruiqing et al [Li Ruiqing, et al. Calculation of phase diagrams of NaCl-CaCl ₂ -BaCl ₂ and NaCl-KCl-BaCl ₂ ternary molten salts. Chemical Metallurgy, 1988, 9(2): 10-16] According to the phase diagram of multiple molten salts Analysis shows that in the NaCl-KCl-BaCl ₂ ternary molten salt system, the minimum eutectic point parameter is 542°C, and the calculated value of the minimum eutectic point is 535°C. In the production process of electrolyzing molten salt LiCl to produce metal lithium, adding an appropriate amount of KCl crystals can reduce the temperature of the electrolytic cell to 400°C, thereby improving the production conditions.

Bao Wenzhong et al analyzed the cycle mechanism of chlorine in the cement production process [Bao Wenzhong, et al. Brief introduction to cement kiln bypass ventilation technology and waste heat utilization. Cement Technology, 2013. (6): 96-99]. Chlorine that enters the firing zone is almost all volatilized, and only a small part is taken away by the clinker. The chloride volatilized in the raw meal and fuel can be combined with the alkali in the raw meal or with the uncombined sulfur that has entered the kiln gas Alkali vapor forms alkali chloride. Chlorine brought into the kiln gas during volatilization is more likely to react with potassium to form potassium chloride. Generally, only after potassium chloride is formed, excess chlorine can form sodium chloride with sodium. The vapor pressure of this compound is close to zero at 800°C to 900°C, that is, at this temperature, almost all of it condenses on the surface of the raw material, causing skinning and blockage in certain areas or equipment. Alkali chloride has a smaller vapor pressure than other alkali compounds, and it reaches the boiling point when the firing temperature in the kiln is below 1450°C, so it volatilizes again shortly after entering the kiln. Therefore, when the chlorine content in the raw meal exceeds a certain limit, the alkali cycle increases sharply, resulting in severe skinning in the preheater or pipeline at a temperature between 800°C and 1000°C, and at the same time, alkali chloride can also form low Melting point mixture, adheres to the surface of the raw meal, reduces the fluidity of the raw meal, and leads to the enhancement of the crust. In the cement kiln, the presence of chlorine element promotes the circulation of alkali.

It is precisely due to the constraints of the inherent characteristics of the cement production process that after waste materials containing potassium chloride components such as domestic garbage and fly ash enter the cement rotary kiln production line for co-processing, the chlorine-containing components (mainly potassium chloride and sodium chloride) It will circulate and enrich in the cement production line, and in severe cases, it will cause ring formation and blockage in the cement rotary kiln, affecting the normal production of the cement kiln. At the same time, the chlorine element brought in by the waste eventually enters the cement clinker, which increases the content of chloride ions in the cement and affects the quality of water cement. Therefore, the efficiency of co-processing chlorine-containing waste in cement rotary kiln is always at a low level.

In order to improve the efficiency of cement rotary kiln co-processing fly ash and other chlorine-containing wastes, two technical routes are currently used: pre-treatment of chlorine-containing wastes and bypass air treatment of cement production.

The pretreatment of chlorine-containing waste is to dechlorinate the chlorine-containing waste before it enters the cement production unit, and the solid residue after dechlorination enters the cement production unit for resource utilization. Because many chlorine-containing wastes are not suitable for pretreatment, they can only be directly sent to the cement production unit, and then the chlorine-containing components are separated by bypass air treatment.

At present, the pretreatment schemes for chlorine-containing waste suitable for pretreatment mostly adopt wet treatment processes such as water washing or pickling [Ning Huayu. Research on the elution of chloride ions and cement solidification in waste incineration fly ash. Cement, 2018, (12): 9-12].

The water washing process is divided into two schemes of potassium chloride resource recovery and non-recovery. The non-recycling solution for potassium chloride resources is to wash solid waste such as chlorine-containing fly ash with water, and the washing water is recycled. The chlorine-containing components entering the liquid phase enter the urban sewage treatment system with the discharged circulating water, and the chlorine components are not recovered.

The potassium chloride resource recovery scheme is to wash the chlorine-containing fly ash with water, recycle the washing water, and concentrate and crystallize the chlorine-containing compounds to prepare industrial salt recovery.

Zhang Zhikun et al [Zhang Zhikun, Wang Jing, Li Haotian, et al. Water elution and cement solidification technology of urban waste incineration fly ash. Science Technology and Engineering, 2019, 19(35):395-401] Dechlorination of fly ash by water washing , when the liquid-solid ratio is 20, the dechlorination rate reaches 74.64%. This technology requires large investment and relatively high disposal costs.

The bypass air release treatment is to directly discharge part of the exhaust gas (temperature above 900°C) in the kiln tail smoke chamber (usually called "bypass air release"), and the exhaust gas will bring out dust to circulate and enrich the flue gas. Potassium, sodium, chlorine, etc. are discharged from the production system, so as to realize the stability of the operation of the cement kiln system and the quality of cement products. For the soot and dust particles drawn by "bypass air release", if the chlorine content is high, the potassium chloride product is usually extracted by water washing or pickling, and the residue after the potassium chloride extraction is dried and mixed into cement clinker, or It is mixed with cement raw meal and enters the cement production unit again.

Mu Luying [Mu Luying. Analysis of cement kiln co-processing solid waste bypass ventilation technology. China Cement, 2019, (4): 105-107] In order to explore the separation and collection effect of chlorine-containing components at different flue gas temperatures , a field test was carried out. The high-temperature flue gas (about 1000-1100°C) is cooled by the quencher to 450-500°C through the bypass bypass, and enters the first-stage cyclone to remove particulate matter, and then mixes cold air at the flue to reduce the flue gas temperature to 250°C After that, it enters the comprehensive reactor, removes dust and other harmful substances, and sends it to the inlet of the kiln tail dust collector through the induced draft fan. The pilot test found that the chloride ions in the bypass flue gas did not condense on the dust at 450°C, but when the flue gas temperature dropped to 250°C, a large amount of chloride ions adhered to the dust. The chloride ion content in the soot particles collected by the first-stage cyclone is only 1.87%, the chlorine ion content in the soot particles removed by the comprehensive processor is 19.58%, and 79.94% of the soot particles are captured in the first-stage cyclone dust collector, 20.06 % of the soot particles are captured in the integrated processor. Although the collection efficiency of the first-stage cyclone dust collector is higher for dust particles, the collection rate for chlorine-containing components is also higher, reaching 27.64%.

Part of the flue gas is drawn from the tail of the cement rotary kiln, which breaks the enrichment cycle chain of chlorine in the cement production line and forms a partial open loop. The extracted flue gas is cooled, dust-removed and purified, and the chlorides in the gaseous state are captured together with the flue dust. The collected smoke and dust particles are mixed into cement clinker, and become cement products after grinding.

Whether it is the chlorine extraction and separation scheme of pretreatment or the chlorine extraction and separation scheme of bypass ventilation, it is necessary to wash or pickle the chlorine-containing solid powder to separate chlorides, and these process schemes all have the following deficiencies:

1) The disposal process route is long. The chlorine-containing components in the fly ash chlorine-containing waste can be dissolved in the liquid phase and separated from the insoluble components in the fly ash by wet method, but the chlorine-containing compounds dissolved in the liquid phase must be crystallized and separated, and chloride crystallization is required , dehydration, drying and other units.

2) The wet process has the risk of secondary pollution of waste liquid. Although the washing solution or pickling solution in the wet treatment process is recycled, and the concentrated solution is crystallized to extract chlorine-containing compounds such as potassium chloride, the fly ash or soot particles contain not only inorganic chlorine-containing compounds, but also a small amount of Organic chlorine compounds, these components are enriched with the circulation of the circulating fluid, and affect the crystallization effect during the concentration and crystallization of inorganic chlorine-containing compounds, and at the same time, a small amount of inclusions enter the crystals of chlorine-containing compounds. In order to improve the separation efficiency of inorganic chlorine-containing compounds, the circulating concentrated liquid must be partially discharged and disposed of independently.

3) Large investment, high operating cost and high energy consumption. The treatment process includes water washing/pickling, crystallization separation, drying and other operating units, especially the solid phase residue after wet chlorine extraction needs to be dried before entering the cement production unit. The entire treatment process has many operating units, high energy consumption, and large investment. High operating costs.

4) The chlorine content in cement clinker is high. For the process technology scheme of redistributing the soot particles with low chlorine content to cement clinker, although it can alleviate the kiln ring formation and blockage in the cement rotary kiln production process, it will not cause the harmful components in the cement to exceed the standard. However, remixing cement clinker will lead to an increase in the content of chlorine components in cement after all. At the same time, there are still a large number of soot particles that do not participate in the firing reaction process of cement clinker. The addition of these components will have a negative impact on the quality of cement products. have a certain impact. Also cause the waste of potassium chloride resource simultaneously.

In order to solve the problems of high separation cost of chlorine-containing components and high risk of secondary environmental pollution in the co-processing of chlorine-containing waste in cement rotary kiln, and to improve the efficiency of co-processing of chlorine-containing waste in cement rotary kiln, it is urgent to develop a non-secondary pollution, operating cost New technology with low investment and low investment.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned technical problems, and to provide a process based on cement kiln co-processing chlorine-containing solid waste, which is simple in process, low in investment cost and operating cost, environmentally friendly, energy-saving and consumption-reducing, and can effectively recover potassium chloride products. Chlorine component dry recovery process.

The technical solution includes the solid waste containing chlorine components entering the cement production line. Under the high-temperature environment in the rotary kiln, the chlorine-containing components are gasified into the flue gas, and part of the flue gas is drawn out from the kiln head flue gas hood of the rotary kiln. The part of the flue gas is sent into the cooling tower after being dedusted by dry method to directly exchange heat with the potassium chloride powder material to cool down. The chlorine-containing components in the flue gas are condensed and enter the potassium chloride powder material. The flue gas is discharged from the top of the cooling tower, and the potassium chloride powder material after heat exchange is discharged from the bottom of the cooling tower.

The dry dust removal includes sending part of the flue gas from the kiln head flue gas hood into the temperature-controlled combustion chamber to adjust the temperature to above 1150°C, and then into the high-temperature dust collector for dust removal and then into the cooling tower.

Gas or natural gas, oxygen-enriched air or oxygen, and straw-like powder materials are fed into the temperature-controlled combustion chamber for combustion to adjust the flue gas temperature to above 1150°C.

The addition amount of the straw-like powder material depends on the molar ratio of chlorine and potassium in the co-processing solid waste, and the injection amount is controlled at 50-100 kg/10,000 Nm ³ of flue gas.

The soot particles separated by the high temperature dust collector are sent into the rotary kiln.

The high-temperature dust collector is a multi-tube cyclone dust collector or a ceramic filter membrane dust collector.

The potassium chloride powder material discharged from the bottom of the cooling tower is sent to the heat exchanger for indirect heat exchange and cooled, and part of it is discharged as a product containing potassium chloride, and the rest is sent back to the cooling tower to exchange heat with flue gas.

After the heat-exchanged flue gas discharged from the top of the cooling tower is dedusted by the bag filter, part of it is drawn as a carrier gas to transport the potassium chloride powder material discharged from the heat exchanger to the cooling tower for heat exchange with the flue gas, and the rest Part of it goes to the grinding machine to heat the cement raw material; the powder discharged from the bottom of the bag filter is the product containing potassium chloride.

For the problems existing in the background technology, the inventor has made the following improvements:

Abandoning the traditional process of wet treatment of flue gas drawn by "bypass ventilation", and overcoming the common understanding of introducing chlorides into the liquid phase through water washing. The analysis found that the flue gas temperature of the rotary kiln is relatively high. At this time, the chlorides in the flue gas are almost all in the gas phase. The content of chlorine is extremely low, and it can be directly returned to the rotary kiln in a hot state (beneficial to the recovery and utilization of waste heat of dust), which effectively reduces the chlorine content in cement and achieves the purpose of chlorine removal in the system; and the chlorine-containing flue gas after dust removal is not wetted. Instead, it is sent to the cooling tower to use the circulating cooling potassium chloride powder material to directly exchange heat and cool down. At the same time, the potassium chloride component in the flue gas condenses and enters the potassium chloride powder material to realize chlorine Recovery of potassium chloride; the flue gas discharged from the top of the cooling tower after heat exchange contains potassium chloride dust, and the potassium chloride product (containing more than 60% by mass percent of potassium chloride) can be separated and recovered through the bag filter, and the separated low temperature The flue gas can enter the pulverizer to heat the cement raw material and further recover the waste heat.

The potassium chloride powder material at the bottom of the tower enters the heat exchanger and indirectly exchanges heat with the cooling water to recover heat energy. When the temperature drops below 150°C, it is recirculated and sent to the cooling tower. The potassium chloride powder material is used as the heat exchange medium to directly cool the high temperature. The flue gas is heat-exchanged and condensed, so that the potassium chloride in the flue gas is continuously condensed in the potassium chloride powder material, which effectively improves the recovery rate and content of the potassium chloride product.

Further, in order to reduce the condensation of potassium chloride into the dust during the dry dust removal process, it is preferable to make the temperature of the flue gas before entering the high-temperature dust collector reach 1150°C or higher. Therefore, a temperature-controlled combustion chamber is added before the high-temperature dust collector. When the flue gas temperature is lower than At 1150°C, the temperature of the flue gas is heated by the temperature-controlled combustion chamber. Further, it is preferable to spray straw-like powder materials into the temperature-controlled combustion chamber. Since the straw is rich in potassium and sodium, the molar ratio of potassium, sodium and chlorine reaches 3, so there is a surplus of potassium, which is beneficial to React with the chlorine element in the flue dust to form potassium chloride [Bao Wenzhong, Zhang Lei, Zhang Fubin. Brief introduction to cement kiln bypass ventilation technology and waste heat utilization. Cement Technology, 2013. (6): 96-99 (chlorine component is volatilized during the volatilization process The chlorine brought into the kiln gas is more likely to react with potassium to form potassium chloride. Generally, only after the formation of potassium chloride, excess chlorine can form sodium chloride with sodium)]. At the same time, in an environment with a temperature of 600°C, the alkali metal chlorides in the straw biomass begin to gasify, and the gasification is basically completed at 900°C. Therefore, it can promote the full gasification of the chlorine element in the particulate matter in the flue gas to generate potassium chloride vapor. The straw-like powder material can be rice, wheat and other straws, and the amount of spraying depends on the molar ratio of chlorine and potassium in the co-processing solid waste. Generally, the amount of spraying is controlled at 50-100kg/10,000 ^Nm3 of flue gas. In order to improve the separation rate of chlorine in the dust and reduce the chlorine content in the cement clinker, too much will cause a waste of potassium resources in the straw, and too little is not conducive to the chlorination of chlorine in the smoke.

The cooling tower can use an existing cooling tower that can realize direct heat exchange, preferably a slag self-cleaning cooling tower, including an upper tower body, a middle annular support, a lower tower body, a hot powder warehouse, and a flue gas inlet. , outlet, powder injection inlet, and coarse powder material outlet, wherein the upper tower body, the lower tower body, and the inner cavity of the hot powder warehouse are axially connected, and the upper and lower ends of the upper tower body are open , There is at least a section of small tower with a diameter reduced by 10-20% in the middle part and a gourd-shaped structure with a diameter enlarged by 10-20% in the lower part. The lower tower body is composed of an outer cylinder and a central pipe, and the outer cylinder is located in the center The periphery of the tube is coaxial with the central tube.

The inventiveness of the slag self-cleaning cooling tower device lies in setting a central pipe in the cooling tower, and skillfully forming a ring seam structure for gas flow. The setting of this structure has the functions of anti-bonding and slag self-cleaning. After the high-temperature gas enters the inner annular seam of the tower tangentially from the air inlet of the cooling tower, the dust is further removed under the action of centrifugal force, and the central tube is heated at the same time, so that the temperature of the central tube is above the melting point or even the boiling point of the potassium chloride component. The central tube is made of heat-resistant steel or ceramic material with good thermal conductivity. The outer side is in long-term contact with the incoming high-temperature gas, and the temperature is close to or even reaches the temperature of the high-temperature flue gas. The inner side is in contact with the fluidized potassium chloride powder material to cool down and partially chlorinated Potassium powder material is heated by the high temperature of the inner wall to become a molten state, and adheres to the inner wall; in addition, the gaseous potassium chloride component in the high-temperature flue gas is cooled by the powder material, and is reduced to below the boiling point temperature, condensed into mist and powdered Body materials are adsorbed, and may also adhere to the wall when it contacts and collides with the inner wall of the central tube. As the wall adhesion surface increases, the adhesion layer becomes thicker, the thermal resistance increases, and the temperature of the inner wall surface of the central tube increases. When the temperature is higher than the boiling point of the slag component, the slag layer melts and falls off.

On the other hand, the structure of the cooling tower is cleverly designed in the shape of a gourd with variable diameter, and at least one gourd neck is set, so that the structure has the following technical effects on the fluidized mixing of the gas-solid mixture:

a, Through the change of the inner diameter, the gas-solid mixture can experience multiple dense-phase regions, dilute-phase regions, dense-phase regions, and dilute-phase regions, which is conducive to the full fluidization of biomass and increases the turbulence of the gas flow in the fluidized bed effect, enhancing gas-solid mixing.

b, The side wall effect and channeling during the operation of the fluidized bed are completely eliminated through the change of the inner diameter.

c. The classification efficiency of powder materials is high. The change of the tower diameter will cause a corresponding change in the gas phase flow rate. In the area where the inner diameter is reduced, the gas phase flow rate is high, and the powder material with a smaller particle size is brought into the previous area with an enlarged inner diameter, and the powder material with a larger particle size falls to the bottom. A region of enlarged inner diameter. As the temperature in the tower gradually decreases from bottom to top, the gas phase flow rate gradually decreases from bottom to top, and the powder material with larger particle size falling to the next area will be fluidized by the larger gas phase flow rate when passing through the area with reduced inner diameter. , is intercepted in this area to further contact with the gas-solid mixture, adhere to the molten droplets, and the particle size further increases. When the particle size is greater than the critical sedimentation particle size, it crosses the small tower diameter section and enters the hot powder bin.

The heat exchanger can use various existing indirect heat exchangers, preferably a powder material spiral heat exchanger, including a powder inlet, a spiral upper shell, a spiral blade, heat exchange tubes, and an exhaust port , upper orifice plate, lower end orifice plate, central water inlet pipe, central water outlet pipe, water inlet head, water outlet head, spiral lower shell, powder outlet, the heat exchange tubes are arranged along the axial direction of the spiral blade Pass through the tube hole on the spiral blade, connect and fix on the upper orifice plate and the lower orifice plate respectively, and connect the water inlet end head and the central water inlet pipe in sequence along the axial ends of the spiral blade through the upper orifice plate and the lower end orifice plate It forms a coaxial rotating body with the head of the water outlet and the central outlet pipe.

The powder material spiral heat exchanger in the invention has compact structure, high space utilization rate and high heat exchange efficiency. When cooling or heating the powder material, the powder material can be filled into the cavity of the passing cylinder to bury the entire heat exchange tube, and the heat exchange area is large.

Beneficial effect:

The invention has the advantages of simple process, small occupied area, low investment cost and low operating cost. Compared with the traditional wet chloride removal process, it saves more than 60% of investment, more than 60% of occupied area, and more than 50% of operating cost; The whole process of dry dust removal does not consume water resources, is environmentally friendly, has no secondary pollution, saves energy and reduces consumption; the recovery rate of potassium chloride is high, and the recovery rate can reach more than 80%; the quality of cement can be improved, and high content of potassium chloride can be recovered at the same time Products, reduce the cost of flue gas treatment, reduce exhaust emissions.

Description of drawings

Fig. 1 is the process flow chart of embodiment 1 of the present invention.

Fig. 2 is the process flow chart of embodiment 2 of the present invention.

Among them, 1. Feed hopper; 2. Main induced draft fan; 3. Cyclone dust collector; 4. Calciner; 5. Bypass air inlet; 6. Rotary kiln; 7. Bag filter; 8-1. Ceramic filter Dust collector; 8-2, multi-tube cyclone dust collector; 9, temperature-controlled combustion chamber; 10, powder nozzle; 11, burner; 12, kiln head sealing cover; A, slag self-cleaning cooling tower; B, powder Bulk material spiral heat exchanger.

Fig. 3 is a structural schematic diagram of a slag self-cleaning cooling tower A of the present invention.

Fig. 4 is A-A sectional view.

Fig. 5 is a front view of the middle annular support A2.

Fig. 6 is a top view of the middle annular support A2.

Fig. 7 is a front view of the annular saddle-shaped silo A6.

Fig. 8 is a top view of the annular saddle-shaped silo A6.

Fig. 9 is a left view of the annular saddle-shaped silo A6.

Among them: A1, upper tower body; A1-1, gas outlet; A1-2, tower diameter contraction section at the outlet end; A1-3, large tower diameter section; A1-4, small tower diameter section; A1-5, gourd Belly section; A1-6, outer arc surface of gourd belly; A2, central annular support; A2-1, inner arc surface of gourd belly; A2-2, inner arc surface of bell mouth; A2-3, heat-resistant concrete; A2-4 , concrete protective steel plate; A2-5, support pad; A3, powder injection inlet; A3-1, lower powder injection inlet; A3-2, middle powder injection inlet; A3-3, upper powder injection inlet; A3 -4, dust return port; A4, lower tower body; A4-1, outer cylinder body; A4-2, central tube; A4-3, outer arc surface of bell mouth; Short tube; A6, annular saddle-shaped silo; A6-1, annular gap-shaped feed port; A6-2, saddle peak; A6-3, saddle-shaped slope; A6-4, dust discharge pipe; A6-5 , Saddle bottom; A6-6, dust unloading valve; A7, hot powder bin; A8, powder feeding pipe; A9, powder unloading valve.

Fig. 10 is a schematic structural view of the powder material spiral heat exchanger B of the present invention.

Fig. 11 is a top view of the powder material spiral heat exchanger of the present invention.

FIG. 12 is a cross-sectional view along line A-A of FIG. 12 .

Fig. 13 is a partial enlarged view of ① in Fig. 10 .

Figure 14 is a partial enlarged view of ② in Figure 10.

Fig. 15 is a schematic diagram of the structure of the helical blade B3.

Among them: B1, powder inlet; 2, screw upper shell; B2-1, upper end sealing plate of upper shell; B2-2, lower end sealing plate of upper shell; B2-3, upper shell flange; B2-4 , perspective hole; B3, spiral blade; B4, heat exchange tube; B5, exhaust port; B6-1, upper purge gas inlet pipe; B6-2, lower purge gas inlet pipe; B6-3, upper blowing B6-4, the lower end purge gas ejection annular seam; B6-5, the outlet of the lower end purge gas; B7-1, the upper end orifice plate; B7-2, the lower end orifice plate; B8-1 , central water inlet pipe; B8-2, central water outlet pipe; B9-1, upper end bearing seat; B9-2, lower end bearing seat; B9-3, bearing; B10-1, upper end head; B10, concrete foundation; B11- 1. Water inlet head; B11-2, water outlet head; B12, screw lower shell; B12-1, upper end sealing plate of the lower shell; B12-2, lower end sealing plate of the lower shell; B12-3, Lower shell flange; B13, powder outlet; B14, sealing ring; B15, annular conductive baffle; B16, air guide ring; B17, annular permanent magnetic baffle; B18, annular spacer; B19, wiring tube; B20 , Void.

Detailed ways

Below in conjunction with accompanying drawing, the present invention will be further explained:

Referring to Fig. 1 and Fig. 2, the system of the present invention is based on a cement kiln co-processing solid waste chlorine-containing component dry separation system, including a rotary kiln 6, and the kiln head flue gas hood 12 of the rotary kiln 6 is provided with a bypass air inlet 5 , the bypass air inlet 5 is connected to the flue gas inlet in the middle of the cooling tower (slag self-cleaning cooling tower A in this embodiment) through the dry dust removal device, and the middle part of the cooling tower is provided with a powder injection inlet; The powder outlet at the bottom of the cooling tower is connected to the heat exchanger (in this embodiment, the powder material spiral heat exchanger B), and the powder outlet of the heat exchanger is respectively connected to the outlet pipe and the powder injection inlet of the cooling tower. The flue gas outlet at the top of the cooling tower is respectively connected to the powder outlet pipeline of the heat exchanger and the gas inlet of the pulverizer through the bag filter 7

The dry dust removal device includes a temperature-controlled combustion chamber 9 and a high-temperature dust collector connected in sequence, and the dust outlet at the bottom of the high-temperature dust collector is connected to the rotary kiln 6 . A burner 11 is provided at the lower part of the temperature-controlled combustion chamber 9, and several powder nozzles 10 are provided above the burner 11 along the circumference of the combustion chamber.

In the present invention, the high-temperature dust collector can be a ceramic filter membrane dust collector 8-1 (see FIG. 1 ) or a multi-tube cyclone dust collector 8-2 (see FIG. 2 ).

crafting process:

The solid waste of chlorine-containing components enters the cement production line (including but not limited to the sequentially connected feed hopper 1, multi-stage cyclone dust collector 3, decomposition furnace 4 and rotary kiln 6 shown in the figure), and in the rotary kiln 6 Under the internal high temperature environment, the chlorine-containing components gasify into the flue gas, and part of the flue gas is drawn from the kiln head flue gas hood 12 of the rotary kiln 6 through the bypass air inlet 5 (the amount of flue gas drawn accounts for the total flue gas amount of the kiln head 4-8% volume percentage), the part of the flue gas drawn is first sent to the temperature-controlled combustion chamber 9 to adjust the temperature to above 1150°C (preferably 1150-1200°C), and then sent to the high-temperature dust collector for dust removal and then sent to the cooling tower Inside. Gas or natural gas, oxygen-enriched air or oxygen is passed into the temperature-controlled combustion chamber 9 for combustion, and at the same time, straw-like powder materials are sprayed into the powder nozzle 10 above the burner 11 for combustion, so as to promote the chlorine element in the particulate matter in the flue gas. Fully vaporized to generate potassium chloride vapor. The addition amount of the straw-like powder material depends on the molar ratio of chlorine and potassium in the co-processing solid waste, and the injection amount is preferably controlled at 50-100kg/10,000 ^Nm3 of flue gas. The soot particles separated by the high temperature dust collector are sent into the rotary kiln 6 .

The high-temperature dust collector is a multi-tube cyclone dust collector 8-2 or a ceramic filter membrane dust collector 8-1. The multi-tube cyclone dust collector 8-2 can remove more than 80% of particulate matter, and the ceramic filter membrane dust collector 8-1 Can remove more than 95% of particulate matter.

After the flue gas is dedusted by dry method, it is sent to the slag self-cleaning cooling tower A to directly exchange heat with the cooled potassium chloride powder material (temperature lower than 150°C) sprayed into the tower, and the chlorine-containing group in the flue gas The flue gas is condensed and enters the potassium chloride powder material, and the flue gas that is cooled to below 250°C by heat exchange is discharged from the top of the tower, and the potassium chloride powder material that is heated to 350-450°C by heat exchange is discharged from the bottom of the tower and sent to the powder The solid material spiral heat exchanger B indirect heat exchange lowers the temperature below 150°C, part of which is discharged as a product containing potassium chloride, and the rest is sent back to the slag self-cleaning cooling tower A to exchange heat with flue gas.

The heat-exchanged flue gas discharged from the top of the cooling tower is dedusted by the bag filter 7, and part of it is drawn out as a carrier gas to transport part of the potassium chloride powder material discharged from the powder material spiral heat exchanger to the slag for self-cleaning The cooling tower A exchanges heat with the flue gas, and the rest goes to the pulverizer to heat the cement raw material; the powder discharged from the bottom of the bag filter 7 is the product containing potassium chloride.

The structure of the slag self-cleaning cooling tower A in this embodiment is described in detail in the previous application with the application number 202010667032.2 and the title of the invention is "High-temperature soot powder fluidized cooling tower based on slag self-cleaning". Referring to Fig. 3-Fig. 9, the technical scheme includes the upper tower body A1, the middle annular support A2, the lower tower body A4, the hot powder warehouse A7, the air inlet A5 (smoke gas inlet), the gas outlet A1-1 (smoke gas inlet). gas outlet), powder injection inlet A3, powder feeding pipe A8 (coarse powder material outlet), the upper tower body A1, the lower tower body A4 and the inner cavity of the hot powder warehouse A7 are axially connected, and the The upper tower body A1 is open at both the upper end and the lower end, and there is at least a small tower diameter section A1-4 in the middle with a 10-20% diameter reduction and a 10-20% gourd belly section A1-5 with a lower diameter expansion. A4 is composed of an outer cylinder A4-1 and a central tube A4-2. The outer cylinder A4-1 is located on the periphery of the central tube A4-2 and is coaxial with the central tube A4-2.

The upper end of the outer cylinder A4-1 of the lower tower body A42 is connected and sealed with the lower edge of the middle annular support A2, and the central pipe A4-2, the middle annular support A2 and the outer cylinder A4-1 An annular space structure with a closed upper end and an open lower end is formed.

The upper tower body A1 rests on the middle annular support A2, and the outer arc surface A1-6 of the gourd belly of the upper tower body A1 is joined with the inner arc surface A2-1 of the gourd belly of the middle annular support A2. The curved surface contacts, fixes and seals.

The lower part of the central tube A4-2 is cylindrical, and the upper port is a bell mouth-shaped structure that expands outwards. The central tube A4-2 is fixed and suspended on the middle annular support A2 through the bell mouth. The outer arc surface A4-3 of the mouth is joined with the inner arc surface A2-2 of the bell mouth of the middle annular support, and is fixed and sealed by the arc surface contact.

The inner arc surface A2-1 of the gourd belly of the central annular support A2 is located above the inner arc surface A2-2 of the bell mouth of the central annular support A2, and several intermediate powders are evenly arranged in the circumferential direction between the two arc surfaces. Body injection inlet A3-3, the powder injection direction of the middle layer powder injection inlet A3-3 points to the center of the gourd belly, and the middle annular support A2 is supported by several columns.

An air inlet 5 is arranged tangentially on the upper side wall of the outer cylinder A4-1. The lower port of the outer cylinder A4-1 of the lower tower body A4 is connected to the upper port of the outer ring of the annular saddle-shaped silo A6, and the inner ring of the annular saddle-shaped silo A6 is a hot powder bin A7 , the hot powder bin A7 is embedded in the inner ring of the annular saddle bin A6, the upper port of the hot powder bin A7 is flush with the upper port of the annular saddle bin, the The diameter of the upper port of the hot powder chamber A7 is equivalent to the diameter of the central tube.

The annular gap-shaped feeding port A6-1 of the annular saddle-shaped silo A6 corresponds to the annular gap of the lower tower body A4, and is located directly below the annular gap of the lower tower body A4, and the annular gap width is the same as that of the lower tower body A4. The girth width is equivalent.

The inclination angle of the saddle-shaped surface of the annular saddle-shaped silo A6 is greater than the angle of repose of the dust, and the bottoms of the two saddles are connected with the dust discharge pipe A6-4 and the dust discharge valve A6-6. The inclination angle of the gourd tripe is greater than the angle of repose of the powder material.

Several lower layer powder injection inlets A3-1 are evenly arranged on the inner ring wall of the annular saddle-shaped silo A6 along the circumferential direction, and the powder injection direction of the lower layer powder injection inlet A3-1 points to the lower port of the central tube In the center, several upper layer powder injection inlets A3-3 are evenly arranged along the circumference of the small tower diameter section of the upper tower body A1, and the powder injection direction of the upper layer powder injection inlet A3-3 is horizontal or inclined downward.

working principle:

The flue gas is introduced into the tower from the air inlet A5 of the outer cylinder A4-1. Controlled by the annular gap structure inside the tower, the gas generates a swirling flow for cyclone dust removal, and the removed dust enters the annular saddle-shaped silo A6. The high-temperature gas after dedusting enters the central pipe A4-2 from the lower port of the central pipe A4-2, and at the same time mixes and fluidizes with the powder material injected into the lower powder injection port A3-1 to form a gas-solid mixture.

In the central tube A4-2, the gas-solid mixture rises with the airflow and performs heat exchange efficiently. The temperature of the powder material rises, and the temperature of the flue gas decreases, and the heat exchange between the powder material and the inner wall of the central tube 4-2.

The central tube A4-2 is made of heat-resistant steel or ceramic material with good thermal conductivity. Its outer side is in long-term contact with the incoming converter flue gas, and the temperature is close to or even reaches the temperature of the electric furnace flue gas. The inner side of the central tube 4-2 is in contact with the fluidized powder The temperature of the material is lowered by contact, and part of the material is heated by the high temperature of the inner wall to become a molten state, and adheres to the inner wall of the central tube A4-2; in addition, the temperature of the potassium chloride in the converter flue gas drops to the boiling point under the cooling effect of the injected powder material Below the temperature, it condenses and is adsorbed by the powder material, and may also adhere to the wall when it contacts and collides with the inner wall of the central tube A4-2. With the increase of the wall adhesion surface, the adhesion layer thickens, the thermal resistance increases, and the temperature of the inner wall surface of the central tube A4-2 increases. When the temperature is higher than the boiling point of the adhesion layer, the adhesion layer on the inner wall melts and falls off.

After the converter flue gas in the central tube A4-2 exchanges heat with the powder material injected into the powder injection port A3-1 of the lower layer, the flue gas cools down. The flue gas after preliminary cooling continues to rise, and when it crosses the upper port of the central pipe A4-2, it is mixed with the powder material injected into the middle layer powder injection port A3-2, and enters the gourd belly section A1-5 of the upper tower body A1. At the same time, the powder material is sprayed from the upper powder injection port A3-3, settles to the lower edge of the gourd belly section A1-5, contacts with the rising gas-solid mixture countercurrently, and mixes. Due to the sudden increase in the cross-sectional area of the gourd belly section A1-5, the flow velocity of the gas-solid mixture from the central pipe A4-2 suddenly decreases, resulting in severe turbulence, forming a swirl, and violently mixing with the settled powder material, which can be quickly exchanged. heat, the flue gas temperature drops further.

In the gourd belly section A1-5, due to the blockage of the powder material layer settled down in the central area, and the sudden increase in the cross-sectional area of the gourd belly section A1-5, the airflow diffuses and flows to the periphery, which intensifies the gas-solid mixture in the gourd. Further mixing in sections A1-5 and increased residence time.

While the powder material is exchanging heat with the gas-solid mixture, the mist droplets condensed by the adsorption part, the particle size further increases, and after exceeding the critical particle size, it settles into the hot powder bin 7 and passes through the powder feeding pipe A8 And the powder ash unloading valve A9 is discharged into the waste heat recovery equipment.

The temperature of the gas-solid mixture after being fully cooled by the gourd belly section A1-5 drops below 200°C, leaving the gourd belly section A1-5, crossing the small tower diameter section A1-4, and further gas-solid mixture in the large tower diameter section A1-3 - Heat exchange between solids, the flue gas temperature drops below 150 °C, the cooled converter flue gas carries powder materials through the outlet end tower diameter shrinkage section A1-2, and is discharged from the gas outlet A1-1.

The structure of the powder material spiral heat exchanger B in this embodiment is described in detail in the previous application with the application number 202010667081.6 and the title of the invention is "a powder material spiral heat exchanger". Referring to Figure 10-Figure 15, the technical solution includes powder inlet B1, spiral upper shell B2, spiral blade B3, heat exchange tube B4, exhaust port B5, upper orifice B7-1, lower orifice A7-2, Central water inlet pipe B8-1, central water outlet pipe B8-2, water inlet head B11-1, water outlet head B11-2, spiral lower shell B12, powder outlet B13, the heat exchange tube B4 along The helical blade B3 axially passes through the tube hole on the helical blade B3, is respectively connected and fixed on the upper orifice plate B7-1 and the lower orifice plate A7-2, and passes through the upper orifice plate B7-1 and the lower orifice plate A7- 2 Connect the water inlet head B11-1, the central water inlet pipe B8-1, the water outlet head B11-2, and the central water outlet pipe B8-2 in turn along the spiral blade axis B3 to form a coaxial rotating body.

The rotating body is located in the closed cylinder cavity formed by the spiral upper casing B2 and the spiral lower casing B12, and the central water inlet pipe B8-1 and the central water outlet pipe B8-2 are connected from the cylinder cavity. Both ends protrude out of the cylinder; the spiral upper shell B2 is composed of the upper end sealing plate B2-1 of the upper shell, the lower end sealing plate B2-2 of the upper shell, the upper shell flange B2-3 and the perspective hole B2- 4. Composition; the spiral lower shell B12 is composed of the upper end sealing plate B12-1 of the lower shell, the lower end sealing plate B12-2 of the lower shell and the flange B12-3 of the lower shell.

The rotating body is coaxial with the cylinder and installed on the concrete foundation with an inclination of 1.5-5%, the cylinder is fixedly installed on the concrete foundation, and the rotating body extends through the center outside the cylinder The water inlet pipe B8-1 and the center water outlet pipe B8-2 are fixedly installed on the upper end bearing seat B9-1 and the lower end bearing seat B9-2 through the bearings installed on the center water inlet pipe B8-1 and the center water outlet pipe B8-2 , the upper end bearing seat B9-1 and the lower end bearing seat B9-2 are fixedly installed on the concrete foundation.

The heat exchange tube array B4 is composed of several metal tubes arranged in parallel. The orifice B7-1 is firmly and sealed connected with the water inlet end head B11-1, the lower end orifice B7-2 is firmly and airtightly connected with the water outlet end head B11-2, and the water inlet end seal is The head B11-1 and the water outlet end head B11-2 have a central hole at the convex top, and the central water inlet pipe B8-1 and the center water outlet pipe B8-2 are respectively firmly and sealed connected to the water inlet end head and the water outlet end head B11-2. The center of the head of the water outlet is also located; the head of the water inlet and the central water inlet pipe B8-1 can be installed together by welding, or can be directly cast into a whole, and the central water inlet B8-1 can also be It can be connected with the flange of the short pipe at the convex top that is integrally cast with the water inlet head B11-1; the water outlet head B11-2 and the central outlet pipe B8-2 can be installed together by welding, It can also be directly cast as a whole, and the central water outlet pipe B8-2 can also be connected with the flange of the short pipe at the convex top which is integrally cast with the water outlet head B11-2.

An annular spacer B18, an annular permanent magnetic stopper B17, and an annular conductive stopper B15 are sequentially arranged between the convex top of the water outlet head B11-2 and the lower end sealing plate of the cylinder, and the annular permanent magnetic stopper B17 Embedded in the air guiding ring B16, the air guiding ring B16, the annular pad B18 and the annular permanent magnetic stopper B17 are set on the central outlet pipe B8-2 and tightly fixed on the water outlet head B11-2 Above; the annular conductive baffle B17 is set on the central outlet pipe B8-2 and tightly fixed on the lower end sealing plate of the cylinder; the air guiding ring B16, the annular spacer B18, and the annular permanent magnetic baffle B17, the annular conductive baffle B15 is coaxial with the central water outlet pipe B8-2.

The lower end sealing plate B2-2 of the upper shell is provided with a lower end purge gas inlet pipe B6-2, and the lower end purge gas inlet pipe B6-2 is sequentially connected to the lower end purge gas ejection annular seam B6-4, and the lower end blower Scavenging gas outlet B6-5; the upper end sealing plate B2-1 of the upper shell is provided with an upper end purge gas inlet pipe B6-1, and the upper end purge gas inlet pipe B6-1 is connected to the upper end purge gas injection ring Sew B6-3.

The material of the annular pad B18 is a heat insulating material with high compressive strength, and the material of the air guiding ring B16 is a heat insulating material.

A wiring tube is arranged on the lower end sealing plate B12-2 of the lower housing, and the conducting wire of the annular conductive baffle B15 is led out of the cylinder through the B19 wiring tube.

The screw upper shell B2 and the screw lower shell B12 are positioned and fixedly connected by flanges.

The heat exchange tube B4 passing through the tube hole of the spiral blade is fixedly connected to the spiral blade B3 by intermittent welding.

The annular spacer B18, the annular permanent magnetic baffle B17, and the annular conductive baffle B15 are sequentially arranged to be sleeved on the central water outlet pipe B8-2 protruding from the outside of the cylinder.

working principle:

In the device of the present invention, the upper end orifice B7-1 and the lower end orifice B7-2 are respectively connected to the water inlet head B11-1, the central water inlet B8-1 and the water outlet end seal in sequence along the axial ends of the spiral blade 3. The head B11-2 and the central outlet pipe B8-2 form a coaxial rotating body for transfer, driving the fly ash to tilt upward from the closed cylindrical cavity surrounded by the upper spiral casing B2 and the lower spiral casing B12 Flowing to the powder outlet B13, and the cooling water that flows in the opposite direction with the inside of the heat exchange tube B4 passes through the tube wall to exchange heat, the temperature of the fly ash decreases, and the temperature of the cooling water rises. When the fly ash is discharged from the powder outlet B13, the temperature When the temperature drops below 100°C, the cooling water will generate water vapor after being heated and lead out from the center outlet pipe B8-2. The rotating body is driven to rotate by a transmission device installed at the outer end of the central water inlet pipe B8-1.

Startup steps:

(1) Before the rotating body is started, the energized wire of the annular conductive baffle B15 drawn from the conductive baffle junction tube B19 sends power to the annular conductive baffle B15, and between the annular permanent magnetic baffle B17 and the annular conductive baffle B15 Under the action of the electromagnetic force between them, the rotating body tilts upwards;

(2) Open the water inlet valve (not shown in the figure), inject cooling water into the rotating body, the cooling water enters the water inlet head B11-1 through the central water inlet pipe B8-1, crosses the upper orifice B7-1, and enters In the heat exchange tube B4, it crosses the lower end orifice B7-2 and enters the water outlet head B11-2, and merges into the central outlet pipe B8-2;

(3) After the heat exchange tubes 4 are filled with water, start the rotating body to drive the upper orifice B7-1, the lower orifice B7-2, the spiral blade B3, the heat exchange tubes B4, etc. to rotate together, and at the same time pass through the powder inlet The powder unloaded into the hot state from B1 enters the inner cavity of the cylinder. Under the rotation and conveying action of the screw blade B3, the powder in the inner cavity of the cylinder moves upwards obliquely, and reverses the heat exchange with the cooling water in the heat exchange tube B4. The cooled fly ash is discharged from the powder outlet B13;

(4) Adjust the amount of unloading powder and the flow rate of cooling water, so as to control the temperature of the fly ash discharged from the powder outlet B13.

Claims (9)

1. A dry recovery process of chlorine components based on the co-processing of chlorine-containing solid waste in cement kilns, including the solid waste containing chlorine components entering the cement production line, and in the high-temperature environment in the rotary kiln, the chlorine-containing components gasify In the air, part of the flue gas is drawn from the flue gas hood of the kiln head of the rotary kiln, which is characterized in that the part of the flue gas drawn out is sent to the cooling tower to directly exchange heat with the potassium chloride powder material for cooling after dry dust removal , the chlorine-containing components in the flue gas condense down and enter the potassium chloride powder material, the flue gas after heat exchange is discharged from the top of the cooling tower, and the potassium chloride powder material after heat exchange is discharged from the bottom of the cooling tower; The potassium chloride powder material discharged from the bottom of the cooling tower is sent to the heat exchanger for indirect heat exchange and cooled, and part of it is discharged as a product containing potassium chloride, and the rest is sent back to the cooling tower to exchange heat with flue gas. 2. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste according to claim 1, characterized in that, the dry dust removal includes sending part of the flue gas from the kiln head flue gas hood into the The temperature in the temperature-controlled combustion chamber is adjusted to above 1150°C, and then sent to the high-temperature dust collector for dust removal and then sent to the cooling tower. 3. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste according to claim 2, characterized in that coal gas or natural gas, oxygen-enriched air or oxygen, and straw are introduced into the temperature-controlled combustion chamber The powder material is burned to adjust the flue gas temperature to above 1150°C. 4. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste according to claim 3, characterized in that the amount of straw-like powder materials added depends on the chlorine and potassium in the co-processing solid waste Depending on the molar ratio, the injection amount is controlled at 50-100kg/10,000 Nm ³ flue gas. 5. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste according to claim 2, characterized in that the soot particles separated by the high-temperature dust collector are sent into the rotary kiln. 6. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste according to claim 2, characterized in that the high-temperature dust collector is a multi-tube cyclone dust collector or a ceramic filter membrane dust collector. 7. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste as claimed in any one of claims 1-6, characterized in that the heat-exchanged flue gas discharged from the top of the cooling tower passes through After the bag filter removes dust, part of it is used as carrier gas to transport the potassium chloride powder material discharged from the heat exchanger to the cooling tower to exchange heat with the flue gas, and the rest goes to the grinding machine to heat the cement raw material; the bag filter The powder discharged from the bottom is the product containing potassium chloride. 8. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste as claimed in any one of claims 1-6, wherein the cooling tower is a slag self-cleaning cooling tower, comprising the upper The tower body, the central annular support, the lower tower body, the hot powder warehouse, the flue gas inlet and outlet, the powder injection inlet, and the coarse powder material outlet, wherein the upper tower body, the lower tower body and the hot powder The inner cavity of the body chamber is axially connected, and the upper and lower ends of the upper tower body are both open, and there is at least a small tower diameter section in the middle with a diameter reduced by 10-20% and a gourd-shaped structure with a diameter enlarged by 10-20% in the lower part. The lower tower body is composed of an outer cylinder and a central pipe, and the outer cylinder is located on the periphery of the central pipe and is coaxial with the central pipe. 9. The chlorine component dry recovery process based on cement kiln co-processing of chlorine-containing solid waste as claimed in claim 1, wherein the heat exchanger is a powder material spiral heat exchanger, comprising a powder inlet, Spiral upper shell, spiral blades, heat exchange tubes, exhaust port, upper orifice plate, lower orifice plate, central water inlet pipe, central water outlet pipe, water inlet end head, water outlet end head, spiral lower shell, powder body outlet, wherein, the heat exchange tubes pass through the tube holes on the helical blade axially along the helical blade, are respectively connected and fixed on the upper orifice plate and the lower orifice plate, and pass through the upper orifice plate and the lower orifice plate along the The axial ends of the helical blade are respectively connected to the head of the water inlet, the central water inlet pipe, the head of the water outlet end, and the central water outlet pipe in sequence to form a coaxial rotating body.

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