System for producing chlorinated polyvinyl chloride from polyvinyl chloride

Abstract

The utility model provides a system for producing chlorinated polyvinyl chloride from polyvinyl chloride. The system comprises a batching unit, a chlorination unit, an acid filtration and neutralization unit, a centrifugation unit and a drying unit which are connected in sequence. By simplifying and optimizing the technological process, the system is more integrated and efficient, the production cycle is shortened, and the labor cost is reduced; meanwhile, environment-friendly treatment links are perfected, acid-containing waste gas and dry dust-containing tail gas are discharged in a standard reaching manner, wastewater is effectively treated, resources are reasonably recycled, and environmental pollution and production cost are reduced.

Description

Technical Field

[0001] This utility model relates to the field of chemical system technology, and in particular to a system for producing chlorinated polyvinyl chloride from polyvinyl chloride. Background Technology

[0002] Chlorinated polyvinyl chloride (CPVC) is a high-performance polymer material obtained by chlorinating polyvinyl chloride (PVC), also known as polychlorinated polyethylene. As an important product of chlorination modification of PVC resin, CPVC not only possesses the excellent properties of PVC itself, but also exhibits advantages unmatched by other engineering plastics, including superior corrosion resistance, aging resistance, heat resistance, flame retardancy, and high mechanical strength. These characteristics have led to the widespread application of CPVC in numerous fields such as power conduits, chemicals, building materials, aerospace, automotive, papermaking, and electrical appliances. Currently, high-quality special-purpose CPVC raw materials in China are basically dependent on imports, and there is also a significant market gap for CPVC resin used in rigid products, which is mainly met by imports. Producing high-quality CPVC resin and reducing my country's dependence on foreign high-quality CPVC resin is crucial.

[0003] Using surplus PVC and chlorine as raw materials, this product is crucial for reshaping the chlor-alkali industry chain and achieving structural adjustment within the chlor-alkali sector. The production of CPVC using the suspension method involves mixing raw PVC with water to form a suspension. Under specific temperature and pressure conditions, chlorine gas is introduced, and an initiator initiates the chlorination reaction. This reaction follows a free radical mechanism, where chloride ions are activated by the initiator to become chlorine free radicals, which are then absorbed by -CH2- or -CHCl- groups, forming three interleaved linkages: -CHCl-CHCl-, -CH2-CCl2-, and -CH2-CHCl-.

[0004] However, the existing production process of CPVC resin in China is cumbersome and lacks efficient integration. The connections between various processes are not smooth, increasing production cycles and labor costs. In the environmental treatment stage, the treatment of acidic waste gas and wastewater generated during the reaction is ineffective. For example, acidic substances in the waste gas are not completely removed, potentially polluting the surrounding environment after discharge; during wastewater treatment, useful components are not effectively recovered and utilized, resulting in resource waste and increasing the difficulty and cost of wastewater treatment.

[0005] Therefore, overcoming the technical deficiencies in the domestic chlorinated polyvinyl chloride production process to meet the market demand for high-quality resin and environmental protection requirements is an urgent problem to be solved. Utility Model Content

[0006] To address the aforementioned problems, this utility model provides a system for producing chlorinated polyvinyl chloride from polyvinyl chloride. The system simplifies and optimizes the process flow, making it more integrated and efficient, shortening the production cycle and reducing labor costs. At the same time, it improves the environmental protection treatment process, ensuring that acidic waste gas and dry dusty exhaust gas meet emission standards, effectively treating wastewater and rationally recycling resources, thereby reducing environmental pollution and production costs.

[0007] The technical solution of this utility model is as follows:

[0008] This utility model provides a system for producing chlorinated polyvinyl chloride from polyvinyl chloride, comprising a batching unit, a chlorination unit, an acid filtration and neutralization unit, a centrifugation unit, and a drying unit connected in sequence.

[0009] The batching unit is used to measure, mix, and stir the raw materials containing polyvinyl chloride, solvents, and additives in proportion to form a polyvinyl chloride suspension, in preparation for the subsequent chlorination reaction.

[0010] Chlorination unit: used to receive the polyvinyl chloride suspension and to cause the polyvinyl chloride suspension to undergo a chlorination reaction when chlorine gas is introduced and an initiator is added;

[0011] Acid filtration and neutralization unit: used to receive the chlorinated liquid generated by the chlorination reaction and perform acid filtration, washing and neutralization treatment;

[0012] Centrifuge unit: used for solid-liquid separation of chlorinated polyvinyl chloride slurry obtained after filtration acid and neutralization treatment, to obtain chlorinated polyvinyl chloride wet filter cake and filtrate;

[0013] Drying unit: used to dry the chlorinated polyvinyl chloride wet filter cake for subsequent finished product packaging.

[0014] Furthermore, the top of the mixing unit is provided with a solvent inlet, and the solvent is water or hydrochloric acid.

[0015] Furthermore, the solvent inlet is connected to a hydrochloric acid pump via a hydrochloric acid preheater, so that the hydrochloric acid pumped by the hydrochloric acid pump is heated to a set temperature by low-pressure steam when passing through the hydrochloric acid preheater before entering the batching unit.

[0016] Furthermore, the top of the batching unit is provided with a water inlet, which is connected to a water storage tank through a desalination main pipe.

[0017] Furthermore, the top of the batching unit is provided with a polyvinyl chloride (PVC) inlet, through which weighed PVC is added to the batching unit using a hopper.

[0018] Furthermore, the top of the batching unit is provided with an additive inlet, which is connected to a storage tank containing additives.

[0019] Furthermore, each raw material conveying pipeline of the batching unit is equipped with several flow meters, which accurately measure the flow rate of different raw materials, thereby conveying the solvent and additives to the batching unit according to the set dosage.

[0020] Furthermore, the mixing unit is equipped with a stirring device inside, which is used to stir the reaction materials to form a polyvinyl chloride suspension, and to remove oxygen when nitrogen is introduced to remove oxygen at an increased temperature.

[0021] Furthermore, the ingredient preparation unit also includes additives, which include at least one of additive A, additive B, and additive C.

[0022] Furthermore, the top of the batching unit is provided with an additive inlet, which is connected to a storage tank containing additives.

[0023] Furthermore, the material of the batching unit is 304 stainless steel.

[0024] Furthermore, the polyvinyl chloride includes either PVC-SG5 or PVC-SG8.

[0025] Furthermore, the chlorination unit includes a chlorination reactor, the top of which is provided with a polyvinyl chloride suspension inlet, which is connected to the bottom of the batching unit through a pipe for receiving the prepared polyvinyl chloride suspension.

[0026] Furthermore, the top of the chlorination reactor is provided with an initiator inlet and a chlorine inlet.

[0027] Furthermore, the chlorine inlet is connected to a chlorine source via a chlorine inlet pipe. When the temperature is raised to a certain level, the chlorine is introduced into the chlorination reactor to carry out the chlorination reaction. The chlorine inlet pipe is equipped with a flow control valve and a pressure monitoring device to accurately control the amount of chlorine introduced and the reaction pressure.

[0028] Furthermore, the top of the chlorination reactor is also equipped with a nitrogen-purging and oxygen-removing device, which is connected to a nitrogen source via a pipeline and is used to perform nitrogen-purging and oxygen-removing operations before and during the reaction.

[0029] Furthermore, the jacket of the chlorination reactor is connected to a steam heating pipe and a warm water circulation pipe. The steam heating pipe is connected to a steam source. During the heating phase, steam enters the jacket through the steam heating pipe to provide heat to the materials inside the chlorination reactor, raising the temperature to the required reaction temperature. When the chlorination reaction reaches 100% of the set chlorine dosage, the steam heating pipe in the jacket is shut off, and the system switches to the warm water circulation pipe. Warm water flows through the jacket via a circulation pump, carrying away the heat generated by the reaction, achieving heat transfer, cooling, and depressurization operations until the reactor temperature drops to 95°C.

[0030] Furthermore, the chlorination unit is equipped with a stirring device inside, which is used to stir the reactants to form a chlorinated liquid, and to remove oxygen when nitrogen is introduced to drive out oxygen at an increased temperature.

[0031] Furthermore, the body of the chlorination reactor is made of Q235-R inner lining ceramic, the jacket is made of Q235-B, and the capacity is 25m³.

[0032] Furthermore, the chlorination reactor is equipped with an exhaust port at the top, which is connected to a vacuum pump via a pipeline. The acidic waste gas generated by the vacuum pump is transported to a scrubber via the pipeline. When vacuuming is required after the chlorination reaction, the acidic waste gas generated by the vacuum pump enters the scrubber through this pipeline. The scrubber is equipped with a dilute alkali inlet, which is connected to a dilute alkali storage device via a pipeline, allowing the dilute alkali to enter the scrubber and neutralize the acidic waste gas. The waste gas treated by the scrubber is connected to a 30m high chimney via a pipeline and discharged into the atmosphere after meeting emission standards.

[0033] Furthermore, the acid filtration and neutralization unit includes an acid filtration vessel, a neutralization vessel, and a mixing tank connected in sequence according to the material flow order.

[0034] Furthermore, the acid filtration vessel is provided with a chlorination liquid inlet at the top or upper middle part, which is connected to the chlorination unit through a pipeline.

[0035] Furthermore, a nitrogen pipeline is connected to the top of the acid filtration vessel. The nitrogen pipeline is equipped with a pressure control valve and a flow meter, and the hydrochloric acid is filtered out by providing nitrogen pressure.

[0036] Furthermore, the body of the acid filtration vessel is made of Q235-R inner lining glass and has a capacity of 25m³.

[0037] Furthermore, the neutralization vessel is provided with an acid filtration inlet at the top or upper middle part, which is connected to the acid filtration vessel via a pipeline.

[0038] The main function of the acid filtration vessel is to perform preliminary treatment on the chlorination liquid. By using nitrogen pressurization, hydrochloric acid is filtered out through its internal filtration device, reducing the pressure of the subsequent neutralization process, improving the efficiency of the entire process, and reducing the processing cost. At the same time, it avoids excessive impurities entering the neutralization vessel and affecting the neutralization effect.

[0039] The main function of the neutralization vessel is to further treat the filtered acid solution after filtration. First, residual acidic substances are removed by washing with water, and then dilute hydrochloric acid is filtered out under nitrogen pressure. Then, water is added to the neutralization vessel for a second washing, and then alkali solution is added to neutralize the residual hydrochloric acid. Wastewater that meets environmental protection requirements is discharged, and the treated liquid is prepared into CPVC slurry.

[0040] Furthermore, the neutralization vessel is made of Q235-R inner lining glass and has a capacity of 25m³.

[0041] Furthermore, a nitrogen pipeline is connected to the top of the neutralization vessel. The nitrogen pipeline is equipped with a pressure control valve and a flow meter, and the dilute hydrochloric acid is filtered out by providing nitrogen pressure.

[0042] Furthermore, the neutralization vessel is equipped with a water inlet pipe, which is used for the first water addition washing operation and the second water addition washing operation. The water inlet pipe is connected to an external water supply system and is equipped with a flow regulating valve to precisely control the water inlet volume.

[0043] Furthermore, the top of the neutralization vessel is provided with an alkali inlet, which is connected to an alkali adding device via a pipe. The pipe is equipped with a metering pump, which can accurately add an appropriate amount of alkali to neutralize the residual hydrochloric acid.

[0044] Furthermore, the neutralization vessel is equipped with a stirring device, such as a stirring blade and a stirring shaft, which is connected to a drive motor at the top to ensure that the materials can be fully mixed and reacted throughout the neutralization process.

[0045] Furthermore, the bottom of the neutralization vessel is provided with a discharge port, which is connected to a slurry delivery pump via a pipe. The slurry delivery pump is then connected to the mixing tank via a pipe, so as to transport the processed CPVC slurry to the mixing tank.

[0046] Furthermore, the neutralization vessel is made of Q235-R inner lining glass and has a capacity of 25m³.

[0047] Furthermore, the mixing tank is made of 304 stainless steel and has a capacity of 200m³.

[0048] Furthermore, the centrifugal unit is equipped with a rotating drum, which generates a strong centrifugal force when rotating at high speed, thereby separating the solids and liquids in the CPVC slurry. The rotating drum can be equipped with a filter screen or filter basket to ensure that solid particles are retained and the liquid can pass through and be discharged smoothly.

[0049] Furthermore, the centrifugal unit is provided with a feed inlet at the bottom, which is connected to the mixing tank via a mixing pump. The mixing pump delivers the CPVC slurry in the mixing tank to the centrifugal unit.

[0050] Furthermore, the centrifuge unit is provided with a drain port at the bottom, which is connected to a mother liquor tank through a pipe for collecting the mother liquor separated by the centrifuge unit.

[0051] Furthermore, the mother liquor tank is equipped with a drain outlet, which is connected to the neutralization vessel via a mother liquor pump. Simultaneously, a portion of the mother liquor pump's outlet pipe leads to the wastewater treatment process. The mother liquor pump is used to transport the mother liquor from the mother liquor tank to the neutralization vessel and the wastewater treatment process in a certain proportion. Its flow rate and head are adjustable to adapt to different production conditions.

[0052] Furthermore, the centrifuge unit has a processing capacity of 1250-2500 kg / h (dry basis) and is made of 316L stainless steel. This material has good corrosion resistance, can adapt to the chemical properties of CPVC slurry, and ensures the service life of the equipment.

[0053] Furthermore, the centrifugal unit is provided with a discharge port at the bottom, which is connected to the subsequent drying unit via a feeder, and is used to transport the CPVC wet filter cake separated by the centrifugal unit to the drying unit.

[0054] Furthermore, the conveying method of the feeder can be screw conveyor, belt conveyor, etc., selected according to the characteristics of the wet filter cake and the layout of the production site, to ensure that the wet filter cake can smoothly and efficiently enter the drying process.

[0055] Furthermore, the starting end of the drying unit is equipped with a vibrating feeder, which is connected to the discharge port of the centrifugal unit. The vibrating feeder is used to uniformly and stably convey the CPVC wet filter cake to the drying unit. Through vibration, it prevents the wet filter cake from clumping or clogging during the conveying process, ensuring smooth feeding.

[0056] Furthermore, the drying unit includes a steam heater, a primary airflow dryer, and a secondary cyclone dryer connected in sequence. The steam heater provides a heat source for the drying process, heating the air to a suitable temperature, and then the hot air enters the primary airflow dryer and the secondary cyclone dryer. The primary airflow dryer uses a high-speed hot airflow to rapidly evaporate moisture from the wet CPVC during its flow; the secondary cyclone dryer further dries the CPVC, improving the drying effect and ensuring that the moisture content of the CPVC meets product requirements.

[0057] Furthermore, the drying unit also includes a cyclone separator and a bag filter connected in sequence, which are connected to the outlet of the secondary cyclone dryer to separate the water-containing hot air generated during the drying process and the dried CPVC. The cyclone separator uses centrifugal force to separate most of the larger CPVC particles from the airflow; the bag filter filters the remaining fine particles to ensure that the discharged air meets environmental emission standards, and the separated CPVC continues to enter the subsequent conveying stage.

[0058] Furthermore, the drying unit also includes a blower and an exhaust fan. The blower is used to send outside air into the steam heater to provide an air source for the drying process. The exhaust fan is installed at the end of the drying unit and discharges the water-containing hot air by generating negative pressure.

[0059] Furthermore, the packaging unit includes a CPVC finished product hopper and an automatic packaging machine connected in sequence.

[0060] Furthermore, the CPVC finished product silo is used to store dried CPVC, and has a discharge port at the bottom, which is connected to an automatic packaging machine through a pipe or conveying device. The discharge port is usually equipped with a control valve to regulate the discharge speed and flow rate of the material.

[0061] Furthermore, the packaging unit includes an automatic packaging machine that packages CPVC according to a set operating procedure. It has functions such as material metering, bagging, and sealing, and can select packaging bags of different specifications according to product requirements.

[0062] Furthermore, the packaging unit also includes a conveying device for connecting the CPVC finished product silo and the automatic packaging machine, and conveying the CPVC in the silo to the feed port of the automatic packaging machine.

[0063] Furthermore, the conveying device is a screw conveyor or a belt conveyor, etc.

[0064] Furthermore, the system also includes a 15% dilute hydrochloric acid tank, a hydrochloric acid concentration tower, and a 31% hydrochloric acid tank connected in sequence.

[0065] Furthermore, the top of the 15% hydrochloric acid tank is provided with an inlet, which is connected to the bottom outlet of the acid filtration vessel through a pipe, thereby transporting the 15% hydrochloric acid discharged from the acid filtration vessel to the 15% hydrochloric acid tank for temporary storage.

[0066] Furthermore, the bottom of the 15% hydrochloric acid tank is provided with a drain port, which is connected to the hydrochloric acid concentration tower through a pipeline. The pipeline is equipped with a pump and valves to control the flow rate and speed of dilute hydrochloric acid delivery.

[0067] Furthermore, the hydrochloric acid concentration tower is used to concentrate 15% hydrochloric acid to produce 31% hydrochloric acid.

[0068] Furthermore, the hydrochloric acid concentration tower has a tower structure, consisting of a tower body, a packing layer, a reboiler, and a condenser. The tower body is made of a material resistant to hydrochloric acid corrosion; the packing layer increases the gas-liquid contact area and improves concentration efficiency; the reboiler provides heat to the bottom of the tower; and the condenser cools the gas distilled from the top of the tower and recovers hydrogen chloride gas.

[0069] Furthermore, the hydrochloric acid concentration tower is equipped with a drain outlet, which is connected to the 31% hydrochloric acid tank via a pipeline, thereby...

[0070] The concentrated hydrochloric acid is then transferred to a 31% hydrochloric acid tank for storage.

[0071] Furthermore, the top of the hydrochloric acid concentration tower is provided with a gas outlet, which is connected to a condenser for recovering the evaporated hydrogen chloride gas.

[0072] Furthermore, the drain outlet of the 15% hydrochloric acid tank can also be directly connected to the alkali neutralization tank through a pipeline, and the neutralized wastewater is then discharged into the plant's wastewater treatment system.

[0073] Furthermore, the 15% hydrochloric acid tank and the 31% hydrochloric acid tank are made of corrosion-resistant materials, such as fiberglass or rubber-lined carbon steel.

[0074] The technical solution provided by this utility model can include the following beneficial effects:

[0075] (1) Process simplification and efficient integration

[0076] This invention simplifies and optimizes the process flow, resulting in a closer and smoother connection between each production unit. The precise metering and rapid mixing of the batching unit quickly provides qualified reaction raw materials to the chlorination unit; the efficient reaction control system of the chlorination unit shortens reaction time; the coordinated operation of the acid filtration, neutralization, and centrifugation units accelerates product separation and purification; and the continuous operation of the drying and packaging units improves product output efficiency. This integrated and efficient system design significantly shortens the overall production cycle, greatly improves production efficiency, enables rapid response to market demands, and enhances the company's market competitiveness.

[0077] (2) Environmental benefits and resource utilization

[0078] The acid filtration vessel of this invention separates the hydrochloric acid after the chlorination reaction for subsequent concentration treatment, achieving hydrochloric acid recovery and reuse, and improving resource utilization. The neutralization vessel effectively removes residual acidic substances, preventing the direct discharge of acidic wastewater and its environmental harm. The centrifuge unit separates the CPVC wet filter cake and filtrate; part of the filtrate is returned to the neutralization vessel for recycling, while the rest enters the wastewater treatment process, reducing water waste and lowering the load on wastewater treatment.

[0079] Hydrochloric acid concentration: The hydrochloric acid concentration tower concentrates 15% dilute hydrochloric acid from the filtration vessel into 31% hydrochloric acid, enabling the recycling or sale of hydrochloric acid. This not only reduces the demand for fresh hydrochloric acid and lowers production costs, but also reduces energy consumption and environmental pollution during the hydrochloric acid production process, and improves the recycling rate of resources.

[0080] Waste gas treatment: For acidic waste gas generated during exhaust replacement at the end of the chlorination reaction in the reactor, and acidic waste gas generated during vacuuming after chlorination, a scrubber with dilute alkaline solution is used to wash the gas, ensuring it meets emission standards before it is discharged through a 30m high chimney, effectively reducing air pollution from acidic gases. The drying unit ensures that dust-laden exhaust gas generated during the drying process is treated by spiral separators and bag filters before being discharged in compliance with standards, reducing dust pollution to the atmosphere. The efficient operation of the entire unit reduces energy consumption and improves energy utilization efficiency, thus demonstrating environmental benefits.

[0081] Wastewater treatment: The acidic wastewater and some of the alkaline wastewater generated by centrifugation are mixed in the collection tank, and after the pH value is adjusted, they are sent to the plant's wastewater treatment plant for further treatment. This avoids the damage to the aquatic ecological environment caused by the direct discharge of acidic and alkaline wastewater, ensures that the wastewater discharge meets environmental protection standards, and protects water resources.

[0082] (3) Product quality

[0083] The optimized system settings and process flow of this invention make the production process more stable and controllable, enabling precise control of reaction conditions and product composition. The produced chlorinated polyvinyl chloride (PVC) products exhibit greater stability and meet high standards in key indicators such as chlorine content, apparent density, and thermal stability time, resulting in a significant improvement in product quality. This high-quality product can meet the needs of high-end sectors such as power conduit, chemicals, and building materials, helping companies expand their market share, increase product selling prices and profit margins, and further enhance their overall competitiveness within the industry. Attached Figure Description

[0084] Figure 1 This is a system flowchart of the present invention.

[0085] The attached figures are labeled as follows:

[0086] 1—Ingredient preparation unit;

[0087] 2—Chlorination reactor;

[0088] 3—Acid filtration kettle;

[0089] 4——Neutralization kettle;

[0090] 5—Mixing tank;

[0091] 6—Centrifuge unit;

[0092] 7—Drying unit;

[0093] 8—Cyclone separator;

[0094] 9—Bag dust collector;

[0095] 10—CPVC finished product silo;

[0096] 11 — Packaging Unit;

[0097] 12-15% hydrochloric acid tank;

[0098] 13—Hydrochloric acid concentration tower;

[0099] 14-31% hydrochloric acid tank;

[0100] 15 — Mother liquor tank;

[0101] 16—Nitrogen-purging and oxygen-removing device. Detailed Implementation

[0102] The following description and accompanying drawings fully illustrate specific embodiments of the present invention to enable those skilled in the art to practice them. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Some portions and features of certain embodiments may be included in or replace portions and features of other embodiments. The scope of the embodiments of the present invention includes the entire scope of the claims and all available equivalents thereof.

[0103] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0104] Example

[0105] A system for producing chlorinated polyvinyl chloride from polyvinyl chloride is provided, comprising a batching unit 1, a chlorination unit, an acid filtration and neutralization unit, a centrifugation unit 6, and a drying unit 7 connected in sequence.

[0106] Batching Unit 1: Used to measure, mix and stir raw materials containing polyvinyl chloride, solvent and additives in proportion to form a polyvinyl chloride suspension, in preparation for subsequent chlorination reaction;

[0107] Chlorination unit: used to receive the polyvinyl chloride suspension and to cause the polyvinyl chloride suspension to undergo a chlorination reaction when chlorine gas is introduced and an initiator is added;

[0108] Acid filtration and neutralization unit: used to receive the chlorinated liquid generated by the chlorination reaction and perform acid filtration, washing and neutralization treatment;

[0109] Centrifuge unit 6: used for solid-liquid separation of chlorinated polyvinyl chloride slurry obtained after filtration acid and neutralization treatment, to obtain chlorinated polyvinyl chloride wet filter cake and filtrate;

[0110] Drying unit 7: Used to dry the chlorinated polyvinyl chloride wet filter cake for subsequent finished product packaging.

[0111] Furthermore, the top of the mixing unit 1 is provided with a solvent inlet, and the solvent is water or hydrochloric acid.

[0112] Furthermore, the solvent inlet is connected to a hydrochloric acid pump via a hydrochloric acid preheater, so that the hydrochloric acid pumped by the hydrochloric acid pump is heated to a set temperature by low-pressure steam when passing through the hydrochloric acid preheater before entering the batching unit 1.

[0113] Furthermore, the top of the batching unit 1 is provided with a water inlet, which is connected to a water storage tank through a desalination main pipe.

[0114] Furthermore, the top of the batching unit 1 is provided with a polyvinyl chloride (PVC) inlet, and the weighed PVC is added to the batching unit through the PVC inlet using a hopper.

[0115] Furthermore, the top of the batching unit 1 is provided with an auxiliary agent inlet, which is connected to a storage tank containing the auxiliary agent.

[0116] Furthermore, each raw material conveying pipeline of the batching unit 1 is equipped with several flow meters, which accurately measure the flow rate of different raw materials, thereby conveying the solvent and additives to the batching unit 1 according to the set dosage.

[0117] Furthermore, the mixing unit 1 is equipped with a stirring device inside, which is used to stir the reaction materials to form a polyvinyl chloride suspension, and to remove oxygen when nitrogen is introduced to remove oxygen at an increased temperature.

[0118] Furthermore, additives are also added to the ingredient unit 1, including at least one of additive A, additive B, and additive C.

[0119] Furthermore, the top of the batching unit 1 is provided with an auxiliary agent inlet, which is connected to a storage tank containing the auxiliary agent.

[0120] Furthermore, the material of the ingredient dispensing unit 1 is 304 stainless steel.

[0121] Furthermore, the polyvinyl chloride includes either PVC-SG5 or PVC-SG8.

[0122] Furthermore, the chlorination unit includes a chlorination reactor 2, the top of which is provided with a polyvinyl chloride suspension inlet, which is connected to the bottom of the batching unit 1 through a pipe for receiving the prepared polyvinyl chloride suspension.

[0123] Furthermore, the top of the chlorination reactor 2 is provided with an initiator inlet and a chlorine inlet.

[0124] Furthermore, the chlorine inlet is connected to a chlorine source via a chlorine inlet pipe. When the temperature is raised to a certain level, the chlorine is introduced into the chlorination reactor 2 to carry out the chlorination reaction. The chlorine inlet pipe is equipped with a flow control valve and a pressure monitoring device to accurately control the amount of chlorine introduced and the reaction pressure.

[0125] Furthermore, the top of the chlorination reactor 2 is also equipped with a nitrogen-purging and oxygen-removing device 16, which is connected to a nitrogen source through a pipeline and is used to perform nitrogen-purging and oxygen-removing operations before and during the reaction.

[0126] Furthermore, the jacket of the chlorination reactor 2 is connected to a steam heating pipe and a warm water circulation pipe. The steam heating pipe is connected to a steam source. During the heating stage, steam enters the jacket through the steam heating pipe to provide heat to the materials inside the chlorination reactor 2, raising the temperature to the required reaction temperature. When the chlorination reaction reaches 100% of the set chlorine dosage, the steam heating pipe of the jacket is closed, and the system switches to the warm water circulation pipe. Warm water flows through the jacket via a circulation pump, carrying away the heat generated by the reaction, achieving heat transfer, cooling, and pressure reduction operations until the reactor temperature drops to 95°C.

[0127] Furthermore, the chlorination unit is equipped with a stirring device inside, which is used to stir the reactants to form a chlorinated liquid, and to remove oxygen when nitrogen is introduced to drive out oxygen at an increased temperature.

[0128] Furthermore, the body of the chlorination reactor 2 is made of Q235-R inner lining ceramic, the jacket is made of Q235-B, and the capacity is 25m³.

[0129] Furthermore, the top of the chlorination reactor 2 is equipped with an exhaust port, which is connected to a vacuum pump via a pipeline. The acidic waste gas generated by the vacuum pump is transported to a scrubber via a pipeline. When vacuuming is required after the chlorination reaction, the acidic waste gas generated by the vacuum pump enters the scrubber through this pipeline. The scrubber is equipped with a dilute alkali inlet, which is connected to a dilute alkali storage device via a pipeline, allowing the dilute alkali to enter the scrubber and neutralize the acidic waste gas. The waste gas treated by the scrubber is connected to a 30m high chimney via a pipeline and discharged into the atmosphere after meeting emission standards.

[0130] Furthermore, the acid filtration and neutralization unit includes an acid filtration vessel 3, a neutralization vessel 4, and a mixing tank 5 connected in sequence according to the material flow order.

[0131] Furthermore, the top or upper middle part of the acid filtration vessel 3 is provided with a chlorination liquid inlet, which is connected to the chlorination unit through a pipeline.

[0132] Furthermore, a nitrogen pipeline is connected to the top of the acid filtration vessel 3. The nitrogen pipeline is equipped with a pressure control valve and a flow meter, and the hydrochloric acid is filtered out by providing nitrogen pressure.

[0133] Furthermore, the body of the acid filtration vessel 3 is made of Q235-R inner lining glass and has a capacity of 25m³.

[0134] Furthermore, the neutralization vessel 4 is provided with an acid filtration inlet at the top or upper middle part, which is connected to the acid filtration vessel 3 through a pipe.

[0135] The main function of the acid filtration vessel 3 is to perform preliminary treatment on the chlorination liquid. By using nitrogen pressurization, hydrochloric acid is filtered out through its internal filtration device, reducing the pressure of the subsequent neutralization process, improving the efficiency of the entire process, and reducing the processing cost. At the same time, it avoids too many impurities from entering the neutralization vessel 4 and affecting the neutralization effect.

[0136] The main function of the neutralization vessel 4 is to further treat the filtered acid solution after filtration. First, residual acidic substances are removed by washing with water, and then dilute hydrochloric acid is filtered out under nitrogen pressure. Then, water is added to the neutralization vessel 4 for a second washing, and then alkali solution is added to neutralize the residual hydrochloric acid. Wastewater that meets environmental protection requirements is discharged, and the treated liquid is prepared into CPVC slurry.

[0137] Furthermore, the neutralization vessel 4 is made of Q235-R inner lining glass and has a capacity of 25m³.

[0138] Furthermore, a nitrogen pipeline is connected to the top of the neutralization vessel 4. The nitrogen pipeline is equipped with a pressure control valve and a flow meter, and the dilute hydrochloric acid is filtered out by providing nitrogen pressure.

[0139] Furthermore, the neutralization vessel 4 is equipped with a water inlet pipe, which is used for the first water addition washing operation and the second water addition washing operation. The water inlet pipe is connected to an external water supply system and is equipped with a flow regulating valve to precisely control the water inlet volume.

[0140] Furthermore, the top of the neutralization vessel 4 is provided with an alkali inlet, which is connected to an alkali adding device through a pipe. The pipe is equipped with a metering pump, which can accurately add an appropriate amount of alkali to neutralize the residual hydrochloric acid.

[0141] Furthermore, the neutralization vessel 4 is equipped with a stirring device, such as a stirring blade and a stirring shaft, which is connected to a drive motor at the top to ensure that the materials can be fully mixed and reacted throughout the neutralization process.

[0142] Furthermore, the bottom of the neutralization vessel 4 is provided with a discharge port, which is connected to a slurry conveying pump through a pipe. The slurry conveying pump is then connected to the mixing tank 5 through a pipe, so as to convey the processed CPVC slurry to the mixing tank 5.

[0143] Furthermore, the neutralization vessel 4 is made of Q235-R inner lining glass and has a capacity of 25m³.

[0144] Furthermore, the mixing tank 5 is made of 304 stainless steel and has a capacity of 200m³.

[0145] Furthermore, the centrifugal unit 6 is equipped with a rotating drum, which generates a strong centrifugal force when rotating at high speed, thereby separating the solid and liquid components in the CPVC slurry. The rotating drum can be equipped with a filter screen or filter basket to ensure that solid particles are retained and the liquid can pass through and be discharged smoothly.

[0146] Furthermore, the centrifugal unit 6 is provided with a feed inlet at the bottom, which is connected to the mixing tank 5 via a mixing pump. The mixing pump transports the CPVC slurry in the mixing tank 5 to the centrifugal unit 6.

[0147] Furthermore, the centrifuge unit 6 is provided with a drain port at the bottom, which is connected to the mother liquor tank 15 through a pipe for collecting the mother liquor separated by the centrifuge unit 6.

[0148] Furthermore, the mother liquor tank 15 is equipped with a drain outlet, which is connected to the neutralization vessel 4 via a mother liquor pump. Simultaneously, a portion of the mother liquor pump's outlet pipe leads to the wastewater treatment process. The mother liquor pump is used to transport the mother liquor in the mother liquor tank 15 to the neutralization vessel 4 and the wastewater treatment process in a certain proportion. Its flow rate and head are adjustable to adapt to different production conditions.

[0149] Furthermore, the centrifuge unit 6 has a processing capacity of 1250-2500 kg / h (dry basis) and is made of 316L stainless steel. This material has good corrosion resistance, can adapt to the chemical properties of CPVC slurry, and ensures the service life of the equipment.

[0150] Furthermore, the centrifugal unit 6 is provided with a discharge port at the bottom, which is connected to the subsequent drying unit 7 via a feeder, and is used to transport the CPVC wet filter cake separated by the centrifugal unit 6 to the drying unit 7.

[0151] Furthermore, the conveying method of the feeder can be screw conveyor, belt conveyor, etc., selected according to the characteristics of the wet filter cake and the layout of the production site, to ensure that the wet filter cake can smoothly and efficiently enter the drying process.

[0152] Furthermore, the starting end of the drying unit 7 is equipped with a vibrating feeder, which is connected to the discharge port of the centrifugal unit 6. The vibrating feeder is used to uniformly and stably convey the CPVC wet filter cake to the drying unit 7. Through the vibration action, it prevents the wet filter cake from clumping or clogging during the conveying process, ensuring smooth feeding.

[0153] Furthermore, the drying unit 7 includes a steam heater, a primary airflow dryer, and a secondary cyclone dryer connected in sequence. The steam heater provides a heat source for the drying process, heating the air to a suitable temperature, and then the hot air enters the primary airflow dryer and the secondary cyclone dryer. The primary airflow dryer uses a high-speed hot airflow to rapidly evaporate moisture from the wet CPVC during its flow; the secondary cyclone dryer further dries the CPVC, improving the drying effect and ensuring that the moisture content of the CPVC meets product requirements.

[0154] Furthermore, the drying unit 7 also includes a cyclone separator 8 and a bag filter 9 connected in sequence, which are connected to the outlet of the secondary cyclone dryer to separate the water-containing hot air generated during the drying process and the dried CPVC. The cyclone separator 8 uses centrifugal force to separate most of the larger CPVC particles from the airflow; the bag filter 9 filters the remaining fine particles to ensure that the discharged air meets environmental emission standards, and the separated CPVC continues to enter the subsequent conveying stage.

[0155] Furthermore, the drying unit 7 also includes a blower and an exhaust fan. The blower is used to send outside air into the steam heater to provide an air source for the drying process. The exhaust fan is installed at the end of the drying unit 7 and discharges the water-containing hot air by generating negative pressure.

[0156] Furthermore, the packaging unit 11 includes a CPVC finished product hopper 10 and an automatic packaging machine connected in sequence.

[0157] Furthermore, the CPVC finished product silo 10 is used to store dried CPVC, and has a discharge port at the bottom, which is connected to an automatic packaging machine through a pipe or conveying device. The discharge port is usually equipped with a control valve to regulate the discharge speed and flow rate of the material.

[0158] Furthermore, the packaging unit 11 includes an automatic packaging machine that packages CPVC according to a set operating procedure. It has functions such as material metering, bagging, and sealing, and can select packaging bags of different specifications according to product requirements.

[0159] Furthermore, the packaging unit 11 also includes a conveying device for connecting the CPVC finished product silo 10 and the automatic packaging machine, and conveying the CPVC in the silo to the feed port of the automatic packaging machine.

[0160] Furthermore, the conveying device is a screw conveyor or a belt conveyor, etc.

[0161] Furthermore, the system also includes a 15% hydrochloric acid tank 12, a hydrochloric acid concentration tower 13, and a 31% hydrochloric acid tank 14 connected in sequence.

[0162] Furthermore, the top of the 15% hydrochloric acid tank 12 is provided with an inlet, which is connected to the bottom outlet of the acid filtration vessel 3 through a pipe, so that the 15% hydrochloric acid discharged from the acid filtration vessel 3 is transported to the 15% hydrochloric acid tank 12 for temporary storage.

[0163] Furthermore, the bottom of the 15% hydrochloric acid tank 12 is provided with a drain port, which is connected to the hydrochloric acid concentration tower 13 through a pipe. The pipe is equipped with a pump and valves to control the flow rate and speed of dilute hydrochloric acid delivery.

[0164] Furthermore, the hydrochloric acid concentration tower 13 is used to concentrate 15% hydrochloric acid to produce 31% hydrochloric acid.

[0165] Furthermore, the hydrochloric acid concentration tower 13 has a tower structure, consisting of a tower body, a packing layer, a reboiler, and a condenser. The tower body is made of a material resistant to hydrochloric acid corrosion; the packing layer increases the gas-liquid contact area and improves concentration efficiency; the reboiler provides heat to the bottom of the tower; and the condenser cools the gas distilled from the top of the tower and recovers hydrogen chloride gas.

[0166] Furthermore, the hydrochloric acid concentration tower 13 is provided with a drain outlet, which is connected to the 31% hydrochloric acid tank 14 through a pipeline, thereby transporting the concentrated hydrochloric acid to the 31% hydrochloric acid tank 14 for storage.

[0167] Furthermore, the top of the hydrochloric acid concentration tower 13 is provided with a gas outlet, which is connected to a condenser for recovering the evaporated hydrogen chloride gas.

[0168] Furthermore, the drain outlet of the 15% hydrochloric acid tank 12 can also be directly connected to the alkali neutralization tank through a pipeline, and the neutralized wastewater is then discharged into the plant's wastewater treatment system.

[0169] Furthermore, the 15% hydrochloric acid tank 12 and the 31% hydrochloric acid tank 14 are made of corrosion-resistant materials, such as fiberglass or rubber-lined carbon steel.

[0170] The raw materials used in this embodiment are as follows:

[0171] Chlorine: purity ≥99.6%, moisture content ≤0.5%, hydrogen content ≤0.4%, oxygen content ≤50ppm.

[0172] Polyvinyl chloride: as shown in Table 1.

[0173] Table 1. Specifications of SPVC (Polyvinyl Chloride) for CPVC Production

[0174]

[0175] The product specifications of the chlorinated polyvinyl chloride generated in this embodiment are shown in Tables 2 and 3 below.

[0176] Table 2 JC-700 Extrusion Grade Chlorinated Polyvinyl Chloride Resin

[0177]

[0178] Table 3 ZS-600 Injection Grade Chlorinated Polyvinyl Chloride Resin

[0179]

[0180] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any other way. Any modifications or equivalent changes made based on the technical essence of the present utility model shall still fall within the scope of protection claimed by the present utility model.

Claims

1. A system for producing chlorinated polyvinyl chloride from polyvinyl chloride, characterized in that, It includes a batching unit (1), a chlorination unit, an acid filtration and neutralization unit, a centrifugation unit (6), and a drying unit (7) connected in sequence, wherein, The batching unit (1) is used to measure, mix and stir the raw materials containing polyvinyl chloride, solvent and additives in proportion to form a polyvinyl chloride suspension, in preparation for the subsequent chlorination reaction; Chlorination unit: used to receive the polyvinyl chloride suspension and to cause the polyvinyl chloride suspension to undergo a chlorination reaction when chlorine gas is introduced and an initiator is added; Acid filtration and neutralization unit: used to receive the chlorinated liquid generated by the chlorination reaction and perform acid filtration, washing and neutralization treatment; Centrifuge unit (6): used to perform solid-liquid separation on the chlorinated polyvinyl chloride slurry obtained after filtration acid and neutralization treatment, to obtain chlorinated polyvinyl chloride wet filter cake and filtrate; Drying unit (7): used to dry the chlorinated polyvinyl chloride wet filter cake for subsequent finished product packaging.

2. The system according to claim 1, characterized in that, The chlorination unit includes a chlorination reactor (2), the top of which is provided with a polyvinyl chloride suspension inlet, which is connected to the bottom of the batching unit (1) through a pipe to receive the prepared polyvinyl chloride suspension.

3. The system according to claim 2, characterized in that, The top of the chlorination reactor (2) is also equipped with a nitrogen-purging and oxygen-removing device (16), which is connected to a nitrogen source through a pipeline and is used to perform nitrogen-purging and oxygen-removing operations before and during the reaction.

4. The system according to claim 3, characterized in that, The jacket of the chlorination reactor (2) is connected to a steam heating pipe and a warm water circulation pipe. The steam heating pipe is connected to a steam source. During the heating stage, steam enters the jacket through the steam heating pipe to provide heat to the material in the chlorination reactor (2) and raise the temperature to the required temperature for the reaction. When the chlorination reaction reaches 100% of the set chlorine amount, the steam heating pipe of the jacket is closed and switched to the warm water circulation pipe. The warm water flows in the jacket through the circulation pump, carrying away the heat generated by the reaction, realizing the heat transfer, cooling and depressurization operation until the reactor temperature drops.

5. The system according to claim 4, characterized in that, The acid filtration and neutralization unit includes an acid filtration vessel (3), a neutralization vessel (4), and a mixing tank (5) connected in sequence according to the material flow order.

6. The system according to claim 5, characterized in that, The bottom of the neutralization vessel (4) is provided with a discharge port, which is connected to a slurry conveying pump through a pipe. The slurry conveying pump is then connected to the mixing tank (5) through a pipe so as to convey the processed CPVC slurry to the mixing tank (5).

7. The system according to claim 5, characterized in that, The centrifugal unit (6) is provided with a feed inlet on its side. The feed inlet is connected to the mixing tank (5) through a mixing pump. The mixing pump transports the CPVC slurry in the mixing tank (5) to the centrifugal unit (6).

8. The system according to claim 5, characterized in that, The centrifuge unit (6) is provided with a drain port at the bottom, which is connected to the mother liquor tank (15) through a pipe to collect the mother liquor separated by the centrifuge unit; the mother liquor tank (15) is provided with a drain port and is connected to the neutralization vessel (4) through a mother liquor pump.

9. The system according to claim 4, characterized in that, The drying unit (7) includes a steam heater, a primary airflow dryer, and a secondary cyclone dryer connected in sequence.

10. The system according to claim 1, characterized in that, The system also includes a 15% hydrochloric acid tank (12), a hydrochloric acid concentration tower (13), and a 31% hydrochloric acid tank (14) connected in sequence.

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