A combination device for reducing the residual amount of polyvinyl chloride resin

Abstract

The utility model provides a kind of combination device for reducing the residual amount of polyvinyl chloride resin, comprising: polymerizer, discharge filter, discharge pump, discharge tank, pouring filter, slurry pouring pump, feed tank, tower inlet filter, tower inlet pump, heat exchanger, stripping column, primary condenser, secondary condenser, liquid seal tank, wastewater tank, vacuum pump set, tower outlet pump, slurry storage tank, hot water tank and hot water pump.The utility model has the following beneficial effects: vacuum pump set removes residual under negative pressure, which is conducive to more sufficient contact between steam and slurry in the stripping column, improves heat and mass transfer efficiency, effectively reduces the residual amount of polyvinyl chloride resin and improves resin quality.

Description

Technical Field

[0001] This utility model belongs to the field of polyvinyl chloride production, and specifically relates to a combined device for reducing the residual amount of polyvinyl chloride resin. Background Technology

[0002] Vinyl chloride is a chemical substance with carcinogenic risks to humans, and its content in polyvinyl chloride (PVC) particles limits its use. In the PVC resin production process, vinyl chloride residue is primarily removed during the stripping process. During PVC resin production, monomer residue mainly exists in the aqueous phase of the resin slurry and inside the PVC resin particles. It is removed mainly through boiling and diffusion methods. In the stripping process, steam enters from the bottom of the stripping tower, and the resin slurry flows into the trays from the top of the tower, where it comes into counter-current contact with the steam for mass and heat transfer to remove residual monomers. After the slurry and steam come into counter-current contact through multiple trays, the residual PVC resin content gradually decreases, and the removed vinyl chloride monomer flows out from the top of the tower with the steam. The degree of boiling and diffusion of the PVC resin slurry in the stripping tower has a significant impact on the amount of resin residue. A combination of vacuum pumps and compressors is commonly used, but the residue removal effect is not ideal. Summary of the Invention

[0003] A combined device for reducing residual polyvinyl chloride resin, characterized in that it comprises: a polymerization reactor, a discharge filter, a discharge pump, a discharge trough, a pouring filter, a slurry pouring pump, a feeding trough, an inlet filter, an inlet pump, a heat exchanger, a stripping tower, a primary condenser, a secondary condenser, a liquid seal tank, a wastewater tank, a vacuum pump set, an outlet pump, a slurry storage tank, a hot water tank, and a hot water pump; the polymerization reactor is connected to the discharge trough via the discharge filter and the discharge pump, and the discharge trough is connected to the pouring filter. The equipment, slurry discharge pump, and stripping tower feed trough are connected. The feed trough is connected to the stripping tower inlet via the inlet filter and inlet pump. The top of the stripping tower is sequentially connected to the primary condenser, secondary condenser, liquid seal tank, and wastewater tank. The inlet and outlet of the vacuum pump unit are connected to the secondary condenser and the low-pressure recovery compression system, respectively. A heat exchanger is installed between the inlet pump and the stripping tower inlet. A steam inlet is installed at the bottom of the stripping tower. The bottom drain of the stripping tower is connected to the drainage ditch. The stripping tower outlet is connected to the heat exchanger via the outlet pump. The heat exchanger is connected to the slurry storage tank. The hot water tank is simultaneously connected to the stripping tower inlet and spray device via a hot water pump.

[0004] Furthermore, the filter, discharge pump, pouring pump, tower inlet pump, tower outlet pump, vacuum pump, and working water filter are all equipped with backup pumps.

[0005] Furthermore, the primary condenser and the secondary condenser are connected in series to improve the stripping effect and enhance the recovery efficiency of polyvinyl chloride resin residue.

[0006] Furthermore, the secondary condenser is connected to the circulating water inlet and outlet, which better removes the heat from the recovered unit, improves the condenser's cooling effect, and enhances the separation effect between the unit and water vapor.

[0007] Furthermore, the heat exchanger is a spiral plate heat exchanger, which has high heat transfer efficiency, is suitable for processing polyvinyl chloride slurry, and reduces the risk of heat exchanger blockage.

[0008] Furthermore, the stripping tower includes eight trays; each tray is equipped with baffles, overflow liquid, and downcomer. The trays are also equipped with evenly distributed small holes and a spray device, and each tray has a steam inlet at its bottom. This internal arrangement of the stripping tower increases the contact area and time between the steam and the slurry, facilitating the boiling and diffusion of residual monomers, resulting in ideal monomer desorption and effectively reducing the residual amount of polyvinyl chloride resin.

[0009] Furthermore, the vacuum pump unit includes a vacuum pump, a steam-water separator, a working water pump, a working water filter, and a working water heat exchanger. The vacuum pump is connected to the steam-water separator, the working water pump is connected to the working water heat exchanger via the working water filter, the working water heat exchanger is connected to the vacuum pump, and the working water pump is connected to the steam-water separator. The working water of the vacuum pump unit is desalinated and dechlorinated water, effectively preventing scale formation and reducing scaling problems in pipes and equipment.

[0010] Preferably, the inlet of the spray device is connected to the outlet of the hot water tank, which ensures thorough rinsing of the slurry, shortens the rinsing time, and helps improve production efficiency.

[0011] Preferably, the vacuum pump unit operates under negative pressure to ensure that steam reaches the top of the stripping tower smoothly and comes into full contact with the resin slurry, ensuring that the slurry in the tower is always in a boiling state, thereby improving the recovery rate of vinyl chloride residue, reducing the resin residue content, lowering the operating pressure of the stripping tower, reducing steam consumption, and improving resin quality.

[0012] The beneficial effects of this invention are: the polyvinyl chloride slurry comes into contact with steam in the stripping tower, and the steam causes the slurry to boil and remove monomers. Under the action of the vacuum pump unit, the negative pressure technology in the tower lowers the boiling point of the slurry, improves the mass transfer efficiency, effectively reduces the residual amount of polyvinyl chloride resin monomers, saves steam consumption, and reduces production costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] Figure 1In the diagram: 1 is the polymerization reactor; 2 is the discharge filter; 3 is the discharge pump; 4 is the discharge trough; 5 is the pouring filter; 6 is the slurry pouring pump; 7 is the feeding trough; 8 is the inlet filter; 9 is the inlet pump; 10 is the heat exchanger; 11 is the stripping tower; 12 is the primary condenser; 13 is the secondary condenser; 14 is the liquid seal tank; 15 is the wastewater tank; 16 is the low-pressure recovery compression system; 17 is the vacuum pump set; 18 is the outlet pump; 19 is the slurry storage tank; 20 is the hot water tank; 21 is the hot water pump; 22 is the steam pipeline; 23 is the trench; 24 is the steam control valve; 25 is the slurry control valve; 26 is the wastewater stripping system.

[0015] Figure 2 This is a schematic diagram of the structure of the vacuum pump unit of this utility model.

[0016] Figure 2 In the diagram: 17-1 is the vacuum pump; 17-2 is the steam-water separator; 17-3 is the working water pump; 17-4 is the working water filter; 17-5 is the working water heat exchanger; 17-6 is the working water pipeline; 17-7 is the vacuum pump inlet regulating valve; 17-8 is the vacuum pump outlet valve; 17-9 is the working water inlet valve; 17-10 is the working water regulating valve. Detailed Implementation

[0017] The technical solutions of this utility model will be described in detail below with reference to the accompanying drawings. Reference numerals indicate components and technologies in this utility model, so that the advantages and features of this utility model can be more easily understood. The following description is a specification of the claims of this utility model, and other specific embodiments related to the claims but not described are also within the scope of the claims.

[0018] like Figure 1 and Figure 2This utility model provides a combined device for reducing the residual amount of polyvinyl chloride resin, comprising: a polymerization reactor 1, a discharge filter 2, a discharge pump 3, a discharge trough 4, a pouring filter 5, a slurry pouring pump 6, a feeding trough 7, an inlet filter 8, an inlet pump 9, a heat exchanger 10, a stripping tower 11, a primary condenser 12, a secondary condenser 13, a liquid seal tank 14, a wastewater tank 15, a low-pressure recovery compression system 16, a vacuum pump set 17, an outlet pump 18, a slurry storage tank 19, a hot water tank 20, and a hot water pump 21; the polymerization reactor 1 is connected to the discharge trough 4 via the discharge filter 2 and the discharge pump 3, and the discharge trough 4 is connected to the stripping tower feeding trough 7 via the pouring filter 5 and the slurry pouring pump 6; the feeding trough 7... The feed inlet of the stripping tower 11 is connected to the inlet filter 8 and the inlet pump 9. The top of the stripping tower 11 is sequentially connected to the primary condenser 12, the secondary condenser 13, the liquid seal tank 14, and the wastewater tank 15. The inlet and outlet of the vacuum pump set 17 are connected to the secondary condenser 13 and the low-pressure recovery compression system 16, respectively. A heat exchanger 10 is provided between the inlet pump 9 and the feed inlet of the stripping tower 11. A steam inlet is provided at the bottom of the stripping tower 11. The bottom sewage outlet of the stripping tower 11 is connected to the drainage ditch 23. The outlet of the stripping tower 11 is connected to the heat exchanger 10 through the outlet pump 18. The heat exchanger 10 is connected to the slurry storage tank 19. The hot water tank 20 is connected to the water inlet of the stripping tower 11 and the spray device of the stripping tower 11 through the hot water pump 21.

[0019] This embodiment provides a combined device for reducing the residual amount of polyvinyl chloride resin, including the following steps: The polymerization suspension in polymerization reactor 1 is discharged into discharge tank 4 via discharge filter 2 and discharge pump 3, and then conveyed to feed tank 7 via discharge filter 5 and slurry discharge pump 6. The slurry from feed tank 7 passes through inlet filter 8 and enters heat exchanger 10 via inlet pump 9 for preheating before entering stripping tower 11. The slurry flows into the trays from the top of the tower, where it comes into counter-current contact with the rising steam for mass and heat transfer. Gaseous monomers flow out from the top of the tower with the steam. The slurry on the trays is desorbed by overflow weirs, baffles, and downcomers to ensure effective desorption of residual monomers. After passing through multiple trays, the amount of residual monomers gradually decreases. The stripped slurry is cooled by discharge pump 18 and heat exchanger 10 before entering slurry storage tank 19.

[0020] The gaseous unit water vapor recovered from the top of the tower passes through the first-stage condenser 12 and the second-stage condenser 13. The gaseous unit is then fed into the low-pressure recovery and compression system 16 by the vacuum pump group 17. The condensed steam condensate enters the liquid seal tank 14 and is then pressed into the wastewater tank 15 for treatment in the wastewater stripping system 26.

[0021] In the description of this utility model, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the purpose of simplifying the description of this utility model and do not indicate or imply that the device or component referred to must have a specific orientation or be constructed in a specific orientation to complete the operation. Therefore, they should not be construed as limitations on this utility model. In the claims, any reference numerals and symbols placed between parentheses should not be construed as limitations on the claims.

[0022] The above description is a preferred embodiment of the present utility model, and is not exhaustive or intended to limit the present utility model to the disclosed form. Those skilled in the art can design various modified alternative embodiments suitable for specific purposes without departing from the scope of the appended claims. Any changes made or equivalent to the technical solution and inventive concept of the present utility model should be covered within the protection scope of the present utility model.

Claims

1. A combined device for reducing the residual amount of polyvinyl chloride resin, characterized in that, include: Polymerization reactor, discharge filter, discharge pump, discharge trough, pouring filter, slurry pouring pump, feed trough, tower inlet filter, tower inlet pump, heat exchanger, stripping tower, primary condenser, secondary condenser, liquid seal tank, wastewater tank, vacuum pump set, tower outlet pump, slurry storage tank, hot water tank, hot water pump; The polymerization reactor is connected to the discharge trough via a discharge filter and a discharge pump. The discharge trough is connected to the stripping tower feed trough via a discharge filter and a slurry discharge pump. The feed trough is connected to the stripping tower inlet via an inlet filter and an inlet pump. The top of the stripping tower is sequentially connected to a primary condenser, a secondary condenser, a liquid seal tank, and a wastewater tank. The wastewater tank is connected to the wastewater stripping system. The inlet and outlet of the vacuum pump group are respectively connected to the secondary condenser and the low-pressure recovery compression system. A heat exchanger is provided between the inlet pump and the stripping tower inlet. A steam inlet is provided at the bottom of the stripping tower. The bottom drain of the stripping tower is connected to a drainage ditch. The stripping tower outlet is connected to the heat exchanger via an outlet pump. The heat exchanger is connected to the slurry storage tank. The hot water tank is simultaneously connected to the stripping tower inlet and a spray device via a hot water pump.

2. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 1, characterized in that: The secondary condenser is connected to the circulating water inlet and outlet.

3. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 1, characterized in that: The heat exchanger is a spiral plate heat exchanger.

4. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 1, characterized in that: The stripping tower includes 8 trays; each tray is equipped with baffles, overflow liquid and downcomer, and small holes are evenly distributed on the trays and a spray device is also provided. Each tray has a steam inlet at the bottom.

5. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 1, characterized in that: The vacuum pump set includes a vacuum pump, a steam-water separator, a working water pump, a working water filter, and a working water heat exchanger.

6. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 5, characterized in that: The working water is desalinated and dechlorinated water.

7. The combined device for reducing the residual amount of polyvinyl chloride resin according to claim 5, characterized in that: The vacuum pump is connected to the steam-water separator, the working water pump is connected to the working water heat exchanger via the working water filter, the working water heat exchanger is connected to the vacuum pump, and the working water pump is connected to the steam-water separator.

Images