Method for stripping paste resin latex

Abstract

The invention discloses a paste resin latex stripping method which comprises the following steps: latex enters a stripping tower from the middle part of the stripping tower through a feeding pipeline, steam enters the stripping tower from the bottom of the stripping tower, the steam entraining moisture and volatile substances in the latex is discharged from the top of the stripping tower and enters a condenser, and the steam enters the stripping tower after being cooled by the condenser; the gas enters from the top of the water-gas separator, the volatile substances enter the lower part of the defoaming tower group from the upper part of the gas-liquid separator, and the gas volatile substances entering the defoaming tower group flow upwards. The method is convenient and simple to operate, provides proper heat transfer temperature difference for the paste resin latex under the indirect heat exchange condition, maintains good stability and fluidity of the latex at a certain temperature, continuously replaces vinyl chloride monomers desorbed from the latex with flowing carrier gas, realizes a continuous mass transfer process, and improves the quality of the paste resin latex. And the carrier gas flows under the forced negative pressure recovery pressure difference and is separated out from the stripping tower, and the content of residual vinyl chloride in the obtained PVC paste resin product meets the food hygiene grade requirement.

Description

Technical Field

[0001] The invention relates to a method for stripping paste resin latex, in particular to the removal of residual VCM of polyvinyl chloride paste resin. Background Art

[0002] Polyvinyl chloride paste resin is prepared by emulsion polymerization of vinyl chloride in water. The initial particle size of PVC in the obtained latex is 0.1-2μm. The latex contains a certain amount of vinyl chloride monomer. If it cannot be effectively removed, it will remain in the paste resin product and form substances that are harmful to human health. PVC paste resin particles are fine and have a large specific surface area. It is very easy to form foam. The latex has a high viscosity and is extremely unstable at high temperatures. It is easy to break the emulsion and precipitate. Therefore, when removing the vinyl chloride monomer contained therein, it is impossible to use traditional technology in a turbulent state, with rapid steam heating and bubbling. Direct mass transfer and heat transfer in the vinyl chloride latex can remove unreacted vinyl chloride.

[0003] Utility model patent CN215691777U discloses a polyvinyl chloride stripping drying system, which includes a discharge tank, a mixing tank, a heat exchanger, a stripping tower, a centrifugal tank, a centrifuge, a crusher and a drying bed. Steam needs to be introduced into the bottom of the stripping tower to provide heat. The steam eventually enters the slurry, and the water can be removed by a centrifugal dehydration device, which does not affect the subsequent treatment. However, for the stripping of latex that does not require dehydration and is directly dried by evaporating water, the entry of steam not only causes the solid content of the material to decrease and increases the drying load, but also the high-temperature steam directly heats the latex, causing the latex to be heated at too high a temperature and demulsification and precipitation, and it cannot flow. The traditional process adopts a kettle or tank intermittent stripping process, the stripping time is long, the operating pressure is low, the vinyl chloride desorption space is limited, the vinyl chloride inside the latex is difficult to diffuse into the gas phase space, and during the stripping process, no carrier gas can be provided to remove the desorbed vinyl chloride, and only static pressure can be formed to diffuse by pressure difference, the desorption effect is not high, and the rate is slow.

[0004] Utility model patent CN216320058U discloses a polyvinyl chloride stripping device, including a stripping tower, a cooler is provided on the top of the stripping tower, the cooler is connected to the VCM recovery pipe, the stripping tower includes an empty tower section and a plurality of tower plates, an annular spray device is provided in the empty tower section, the spray device is connected to a spray water pipe, the stripping tower wall below the lower tower plate is connected to a steam pipe, the stripping tower wall above the upper tower plate is connected to a slurry inlet pipe, and the bottom of the stripping tower is connected to a slurry outlet pipe; this patent is suitable for the stripping of suspended PVC slurry with coarse particles, good thermal stability, and free flow in a high-temperature boiling state. However, for materials that are extremely unstable to heat and have extremely fine particles, it is impossible to ensure that they can maintain a flowing state at high temperatures, and it is very easy to form a large amount of foam to block the recovery gas pipeline, so it is not suitable for paste resin stripping. Summary of the invention

[0005] The present invention provides a suitable heat transfer temperature difference for the paste resin latex under indirect heat exchange conditions, maintains good stability and fluidity of the latex at a certain temperature, and continuously replaces the vinyl chloride monomer precipitated from the latex with a flowing carrier gas to realize a continuous mass transfer process. The carrier gas flows under a forced negative pressure recovery pressure difference and is separated from the stripping tower without increasing the water content of the material. The residual vinyl chloride content in the obtained PVC paste resin product meets the food hygiene grade requirements.

[0006] The present invention provides the following technical solution: a method for stripping paste resin latex, the steps are as follows: (1) The latex enters the stripping tower from the middle of the stripping tower through the feed pipeline, and the steam enters the stripping tower from the bottom of the stripping tower. After the steam and the latex are in reverse contact inside the stripping tower, the steam entrains the water and volatile substances in the latex and is discharged from the top of the stripping tower into the condenser. The latex with the water and volatile substances removed is sent to the drying system through the latex discharge pump; (2) After being cooled by the condenser, the steam containing water and volatile substances enters from the top of the water-gas separator. The cooled water condenses at the bottom of the water separator and is discharged into the wastewater treatment system. The volatile substances enter the lower part of the degassing tower group from the upper part of the gas-liquid separator. (3) The volatile substances in the gas entering the degassing tower group flow upward and are sent to the gas recovery system from the top of the degassing tower group. The latex foam sinks to the bottom of the degassing tower for recycling.

[0007] Furthermore, the stripping tower is provided with falling film tubes, both ends of which are fixed on the tube sheet, the upper end of the falling film tubes passes through the tube sheet 50-80 mm as an overflow weir, hot water is introduced into the shell side of the falling film tubes, a guide pipe is provided on the upper part of the falling film tubes, the guide pipe is inserted concentrically with the upper end of the falling film tubes, a gap of 3-5 mm is formed between the outer wall of the guide pipe and the inner wall of the falling film tubes, the latex enters the overflow weir from the upper part of the overflow weir, the latex overflows evenly, and flows downward along the inner wall of the falling film tubes in the gap to form a liquid film, and the falling film A steam spray pipe is provided below the tube array, and a trapezoidal steam nozzle is provided on the upper part of the steam spray pipe. The steam nozzle is inserted concentrically with the lower end of the falling film tube array, and steam is sprayed into the falling film tube array. After the steam and the liquid film are in reverse contact in the falling film tube array, the steam entrains water and volatile substances and flows upward through the guide pipe and is discharged into the upper part of the stripping tower. The steam spray pipe of the falling film tube array is connected to the steam pipe at the lower part of the stripping tower and is wrapped with a heat-insulating protection tube on the outside. The heat-insulating protection tube allows the latex after the volatile substances are removed to be directly heated to cause demulsification and precipitation, making it unable to flow.

[0008] Furthermore, the guide pipe is detachably installed on the tube sheet, and the guide pipe passes through the tube sheet by 70-90 mm. The gas is discharged through the guide pipe, and the latex flows downward through the gap between the guide pipe and the falling film tube array. The gas phase and the liquid phase are not in direct contact, thereby achieving the purpose of separating the gas and liquid phases.

[0009] Furthermore, the diameter of the steam nozzle is 15-20 mm, the diameter of the steam nozzle is 8-10 mm, and the length of the steam nozzle is 600-700 mm.

[0010] Furthermore, the pressure at the top of the stripping tower is -15 to -70 kPa, and temperature-increasing negative pressure recovery is adopted to improve gas recovery efficiency.

[0011] Furthermore, the temperature of the steam is 80-90°C.

[0012] Furthermore, the temperature of the hot water is 70-80°C, and the hot water enters from the outer side of the lower shell of the falling film tubes and is discharged from the outer side of the upper shell of the falling film tubes. The hot water in the shell of the falling film tubes keeps the temperature of the falling film tubes constant, preventing the falling film tubes from overheating or heat loss due to too low a temperature, which does not reach the temperature for converting the volatile substances from the liquid phase to the gas phase.

[0013] Furthermore, the condenser uses 7°C cooling water for heat exchange, and the temperature of the vinyl chloride gas after cooling is 20-30°C.

[0014] Furthermore, the feed pipeline is provided with a latex feed pump and a flow controller, and the flow rate is controlled at 60-70m 3 / h.

[0015] Furthermore, the vinyl chloride content of the paste resin latex after stripping is less than or equal to 1 ppm / 0.1 g, and the water content of the latex after stripping is reduced by 55%-57%.

[0016] Compared with the prior art, the present invention applies falling film evaporation technology and the principle of destroying phase equilibrium by reducing the vapor pressure of the liquid surface, and is applied to the process of removing vinyl chloride from paste resin latex. The main heat source is the hot water in the falling film tube. After the material passes through the falling film tube, the large flow rate of the material is converted into a liquid film with a low flow rate and a high surface area, thereby increasing the heat transfer area and improving the heat transfer efficiency, providing sufficient energy and space for the diffusion of vinyl chloride in the tower, and using low-pressure steam as the carrier gas. Under negative pressure, the vapor pressure of water at the gas-liquid interface is not increased, and the diffusion of steam from the gas phase to the liquid phase is reduced, thereby increasing the water content of the latex. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 is a partial front view of the stripping tower of the present invention; Figure 3 is a diagram of a steam nozzle of a stripping tower of the present invention; Figure 4 It is a falling film tube diagram of the stripping tower of the present invention; Figure 5 It is a draft tube diagram of the stripping tower of the present invention; Figure 61. It is a top view of the falling film tube array of the stripping tower of the present invention; Figure 1-6 As shown in: 1 is the latex feed pump, 2 is the stripping tower, 3 is the latex discharge pump, 4 is the top condenser, 5 is the vapor-liquid separator, 6 is the degassing tower group, 7 is the recovery vacuum unit, 8 is the flow regulator, 9 is the liquid level regulator, 10 is the steam nozzle, 11 is the insulation protection tube, 12 is the tube sheet, 13 is the guide tube, 14 is the falling film tube array, a is the latex inlet, b is the latex, c is the steam inlet, d is the volatile substance, e is the hot water inlet, and f is the hot water outlet. Implementation

[0018] Example 1, reference Figure 1-6 , a method for stripping paste resin latex, the steps are as follows: (1) The latex enters the stripping tower from the middle of the stripping tower through the feed pipeline, and the steam enters the stripping tower from the bottom of the stripping tower. After the steam and the latex are in reverse contact inside the stripping tower, the steam entrains the water and volatile substances in the latex and is discharged from the top of the stripping tower into the condenser. The latex with the water and volatile substances removed is sent to the drying system through the latex discharge pump; (2) After being cooled by the condenser, the steam containing water and volatile substances enters from the top of the water-gas separator. The cooled water condenses at the bottom of the water separator and is discharged into the wastewater treatment system. The volatile substances enter the lower part of the degassing tower group from the upper part of the gas-liquid separator. (3) The volatile substances in the gas entering the degassing tower group flow upward and are sent to the gas recovery system from the top of the degassing tower group. The latex foam sinks to the bottom of the degassing tower for recycling.

[0019] There are falling film tubes inside the stripping tower. Both ends of the falling film tubes are fixed on the tube sheet. The upper end of the falling film tubes passes through the tube sheet for 50-80mm as an overflow weir. The lower end plate is flush with the lower port of the tube bundle. Hot water is introduced into the shell side of the falling film tubes. A guide pipe is provided on the upper part of the falling film tubes. The guide pipe is inserted concentrically with the upper end of the falling film tubes. A gap of 3-5mm is formed between the outer wall of the guide pipe and the inner wall of the falling film tubes. The latex enters the overflow weir from the upper part of the overflow weir, and the latex overflows evenly and flows downward along the inner wall of the falling film tubes in the gap to form a liquid film. A steam spray pipe is provided below the falling film tube array, and a trapezoidal steam nozzle is provided on the upper part of the steam spray pipe. The steam nozzle is inserted concentrically with the lower end of the falling film tube array, and steam is sprayed into the falling film tube array. After the steam and the liquid film are in reverse contact in the falling film tube array, the steam entrains water and volatile substances and flows upward through the guide pipe and is discharged into the upper part of the stripping tower. The steam spray pipe of the falling film tube array is connected with the steam pipe at the lower part of the stripping tower, and is wrapped with a heat-insulating protection tube on the outside. The heat-insulating protection tube makes the latex after the volatile substances are removed directly heated to cause demulsification and precipitation, and it cannot flow.

[0020] The degassing tower group is composed of two degassing towers connected in series. A conical wire mesh is designed inside the degassing tower. Spikes are arranged at the bottom of the wire mesh. The conical wire mesh of the degassing tower group is designed in multiple layers. The recovery vacuum unit is a water ring vacuum pump. The flow rate of the stripping tower feed pipeline is controlled by the flow controller using DCS. The flow rate of the stripping tower discharge pipeline is controlled by the liquid level controller using DCS.

[0021] The guide pipe is detachably installed on the tube sheet. The guide pipe passes through the tube sheet for 70mm. The gas is discharged through the guide pipe, and the latex flows downward through the gap between the guide pipe and the falling film tube array. The gas phase and the liquid phase do not directly contact each other, thus achieving the purpose of separating the gas and liquid phases.

[0022] The diameter of the steam nozzle is 20 mm, the diameter of the steam nozzle is 10 mm, and the length of the steam nozzle is 700 mm.

[0023] The pressure at the top of the stripping tower is -15kPa, and temperature-increasing negative pressure recovery is used to improve gas recovery efficiency.

[0024] The temperature of the steam is 80°C.

[0025] The temperature of the hot water is 70°C. The hot water enters from the outer side of the lower shell of the falling film tubes and is discharged from the outer side of the upper shell of the falling film tubes. The hot water in the shell of the falling film tubes keeps the temperature of the falling film tubes constant to prevent the falling film tubes from overheating or heat loss due to too low a temperature that does not reach the temperature for converting volatile substances from liquid phase to gas phase.

[0026] The condenser uses 7℃ cooling water for heat exchange, and the temperature of the vinyl chloride gas after cooling is 20℃.

[0027] The feed pipeline is equipped with a latex feed pump and a flow controller, and the flow rate is controlled at 60m 3 / h.

[0028] The vinyl chloride content of the paste resin latex after stripping is less than or equal to 1 ppm / 0.1 g, and the water content of the latex after stripping is reduced by 55%.

[0029] Example 2, reference Figure 1-6 , a method for stripping paste resin latex, the steps are as follows: (1) The latex enters the stripping tower from the middle of the stripping tower through the feed pipeline, and the steam enters the stripping tower from the bottom of the stripping tower. After the steam and the latex are in reverse contact inside the stripping tower, the steam entrains the water and volatile substances in the latex and is discharged from the top of the stripping tower into the condenser. The latex with the water and volatile substances removed is sent to the drying system through the latex discharge pump; (2) After being cooled by the condenser, the steam containing water and volatile substances enters from the top of the water-gas separator. The cooled water condenses at the bottom of the water separator and is discharged into the wastewater treatment system. The volatile substances enter the lower part of the degassing tower group from the upper part of the gas-liquid separator. (3) The volatile substances in the gas entering the degassing tower group flow upward and are sent to the gas recovery system from the top of the degassing tower group. The latex foam sinks to the bottom of the degassing tower for recycling.

[0030] Falling film tubes are arranged inside the stripping tower. Both ends of the falling film tubes are fixed on the tube sheet. The upper end of the falling film tubes passes through the tube sheet for 65mm as an overflow weir. The lower end plate is flush with the lower port of the tube bundle. Hot water is introduced into the shell side of the falling film tubes. A guide pipe is arranged on the upper part of the falling film tubes. The guide pipe is inserted concentrically with the upper end of the falling film tubes. A gap of 4mm is formed between the outer wall of the guide pipe and the inner wall of the falling film tubes. The latex enters the overflow weir from the upper part of the overflow weir. The latex overflows evenly and flows downward along the inner wall of the falling film tubes in the gap to form a liquid film. A steam spray pipe is provided below the film tube array, and a trapezoidal steam nozzle is provided on the upper part of the steam spray pipe. The steam nozzle is inserted concentrically with the lower end of the falling film tube array, and steam is sprayed into the falling film tube array. After the steam and the liquid film are in reverse contact in the falling film tube array, the steam entrains water and volatile substances and flows upward through the guide pipe and is discharged into the upper part of the stripping tower. The steam spray pipe of the falling film tube array is connected to the steam pipe at the lower part of the stripping tower and is wrapped with a heat-insulating protection tube on the outside. The heat-insulating protection tube allows the latex after the volatile substances are removed to be directly heated to cause demulsification and precipitation, making it unable to flow.

[0031] The degassing tower group is composed of two degassing towers connected in series. A conical wire mesh is designed inside the degassing tower. Spikes are arranged at the bottom of the wire mesh. The conical wire mesh of the degassing tower group is designed in multiple layers. The recovery vacuum unit is a water ring vacuum pump. The flow rate of the stripping tower feed pipeline is controlled by the flow controller using DCS. The flow rate of the stripping tower discharge pipeline is controlled by the liquid level controller using DCS.

[0032] The guide pipe is detachably installed on the tube sheet. The guide pipe passes through the tube sheet for 80mm. The gas is discharged through the guide pipe, and the latex flows downward through the gap between the guide pipe and the falling film tube array. The gas phase and the liquid phase do not directly contact each other, thus achieving the purpose of separating the gas and liquid phases.

[0033] The diameter of the steam nozzle is 18 mm, the diameter of the steam nozzle is 9 mm, and the length of the steam nozzle is 650 mm.

[0034] The pressure at the top of the stripping tower is -30kPa, and temperature-increasing negative pressure recovery is used to improve gas recovery efficiency.

[0035] The temperature of the steam is 85°C.

[0036] The temperature of hot water is 75℃. Hot water enters from the outer side of the lower shell of the falling film tubes and is discharged from the outer side of the upper shell of the falling film tubes. The hot water in the shell of the falling film tubes keeps the temperature of the falling film tubes constant to prevent the falling film tubes from overheating or heat loss due to too low a temperature that does not reach the temperature for converting volatile substances from liquid phase to gas phase.

[0037] The condenser uses 7℃ cooling water for heat exchange, and the temperature of the vinyl chloride gas after cooling is 25℃.

[0038] The feed pipeline is equipped with a latex feed pump and a flow controller, and the flow rate is controlled at 65m 3 / h.

[0039] The vinyl chloride content of the paste resin latex after stripping is less than or equal to 1 ppm / 0.1 g, and the water content of the latex after stripping is reduced by 56%.

[0040] Example 3, reference Figure 1-6 , a method for stripping paste resin latex, the steps are as follows: (1) The latex enters the stripping tower from the middle of the stripping tower through the feed pipeline, and the steam enters the stripping tower from the bottom of the stripping tower. After the steam and the latex are in reverse contact inside the stripping tower, the steam entrains the water and volatile substances in the latex and is discharged from the top of the stripping tower into the condenser. The latex with the water and volatile substances removed is sent to the drying system through the latex discharge pump; (2) After being cooled by the condenser, the steam containing water and volatile substances enters from the top of the water-gas separator. The cooled water condenses at the bottom of the water separator and is discharged into the wastewater treatment system. The volatile substances enter the lower part of the degassing tower group from the upper part of the gas-liquid separator. (3) The volatile substances in the gas entering the degassing tower group flow upward and are sent to the gas recovery system from the top of the degassing tower group. The latex foam sinks to the bottom of the degassing tower for recycling.

[0041] Falling film tubes are arranged inside the stripping tower. Both ends of the falling film tubes are fixed on the tube sheet. The upper end of the falling film tubes passes through the tube sheet for 80mm as an overflow weir. The lower end plate is flush with the lower port of the tube bundle. Hot water is introduced into the shell side of the falling film tubes. A guide pipe is arranged on the upper part of the falling film tubes. The guide pipe is inserted concentrically with the upper end of the falling film tubes. A gap of 5mm is formed between the outer wall of the guide pipe and the inner wall of the falling film tubes. The latex enters the overflow weir from the upper part of the overflow weir. The latex overflows evenly and flows downward along the inner wall of the falling film tubes in the gap to form a liquid film. A steam spray pipe is provided below the film tube array, and a trapezoidal steam nozzle is provided on the upper part of the steam spray pipe. The steam nozzle is inserted concentrically with the lower end of the falling film tube array, and steam is sprayed into the falling film tube array. After the steam and the liquid film are in reverse contact in the falling film tube array, the steam entrains water and volatile substances and flows upward through the guide pipe and is discharged into the upper part of the stripping tower. The steam spray pipe of the falling film tube array is connected to the steam pipe at the lower part of the stripping tower and is wrapped with a heat-insulating protection tube on the outside. The heat-insulating protection tube allows the latex after the volatile substances are removed to be directly heated to cause demulsification and precipitation, making it unable to flow.

[0042] The degassing tower group is composed of two degassing towers connected in series. A conical wire mesh is designed inside the degassing tower. Spikes are arranged at the bottom of the wire mesh. The conical wire mesh of the degassing tower group is designed in multiple layers. The recovery vacuum unit is a water ring vacuum pump. The flow rate of the stripping tower feed pipeline is controlled by the flow controller using DCS. The flow rate of the stripping tower discharge pipeline is controlled by the liquid level controller using DCS.

[0043] The guide pipe is detachably installed on the tube sheet. The guide pipe passes through the tube sheet for 90mm. The gas is discharged through the guide pipe, and the latex flows downward through the gap between the guide pipe and the falling film tube array. The gas phase and the liquid phase do not directly contact each other, thus achieving the purpose of separating the gas and liquid phases.

[0044] The diameter of the steam nozzle is 15 mm, the diameter of the steam nozzle is 8 mm, and the length of the steam nozzle is 600 mm.

[0045] The pressure at the top of the stripping tower is -70kPa, and temperature-increasing negative pressure recovery is used to improve gas recovery efficiency.

[0046] The temperature of the steam is 90°C.

[0047] The temperature of the hot water is 80°C. The hot water enters from the outer side of the lower shell of the falling film tubes and is discharged from the outer side of the upper shell of the falling film tubes. The hot water in the shell of the falling film tubes keeps the temperature of the falling film tubes constant to prevent the falling film tubes from overheating or heat loss due to too low a temperature that does not reach the temperature for converting volatile substances from liquid phase to gas phase.

[0048] The condenser uses 7℃ cooling water for heat exchange, and the temperature of the vinyl chloride gas after cooling is 30℃.

[0049] The feed pipeline is equipped with a latex feed pump and a flow controller, and the flow rate is controlled at 70m 3 / h.

[0050] The vinyl chloride content of the paste resin latex after stripping is less than or equal to 1 ppm / 0.1 g, and the water content of the latex after stripping is reduced by 57%.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several changes and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for stripping a paste resin latex, comprising the following steps: The latex enters the stripping tower from the middle of the stripping tower through the feed pipeline, and the steam enters the stripping tower from the bottom of the stripping tower. After the steam and the latex are in reverse contact inside the stripping tower, the steam entrains the water and volatile substances in the latex and is discharged from the top of the stripping tower into the condenser. The latex with the water and volatile substances removed is sent to the drying system through the latex discharge pump; The steam with water and volatile substances is cooled by the condenser and then enters from the top of the water-gas separator. The cooled water condenses at the bottom of the water separator and is discharged into the wastewater treatment system. The volatile substances enter the lower part of the degassing tower group from the upper part of the gas-liquid separator. The volatile substances in the gas entering the degassing tower group flow upward and are sent to the gas recovery system from the top of the degassing tower group. The latex foam sinks to the bottom of the degassing tower for recycling.

2. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The stripping tower is provided with falling film tubes inside, and both ends of the falling film tubes are fixed on the tube sheet. The upper end of the falling film tubes passes through the tube sheet 50-80mm as an overflow weir, and hot water is introduced into the shell side of the falling film tubes. A guide pipe is provided on the upper part of the falling film tubes. The guide pipe is inserted concentrically with the upper end of the falling film tubes, and a 3-5mm gap is formed between the outer wall of the guide pipe and the inner wall of the falling film tubes. The latex enters the overflow weir from the upper part of the overflow weir, and the latex overflows evenly and flows downward along the inner wall of the falling film tube in the entering gap to form a liquid film. A steam nozzle is provided below the falling film tube, and a trapezoidal steam nozzle is provided on the upper part of the steam nozzle. The steam nozzle is inserted concentrically with the lower end of the falling film tube, and steam is sprayed into the falling film tube. After the steam and the liquid film are in reverse contact in the falling film tube, the steam entrains water and volatile substances and flows upward through the guide pipe and is discharged into the upper part of the stripping tower. The steam nozzle of the falling film tube is connected with the steam pipe at the lower part of the stripping tower, and is wrapped with a heat-insulating protection tube on the outside.

3. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The guide pipe is detachably mounted on the tube sheet, and the upper end of the guide pipe passes through the tube sheet by 70-90 mm.

4. A method for stripping a paste resin latex as claimed in claim 2, characterized in that: The diameter of the steam spray pipe is 15-20 mm, the diameter of the steam nozzle is 8-10 mm, the length of the steam nozzle is 10-15 mm, and the length of the steam spray pipe is 600-700 mm.

5. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The pressure at the top of the stripping tower is -15 to -70 kPa.

6. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The temperature of the steam is 80-90°C.

7. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The temperature of the hot water is 70-80° C. The hot water enters from the outer side of the lower part of the shell side of the falling film tubes and is discharged from the outer side of the upper part of the shell side of the falling film tubes.

8. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The condenser uses 7℃ cooling water for heat exchange, and the temperature of the cooled vinyl chloride gas is 20-30℃.

9. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The feed pipeline is provided with a latex feed pump and a flow controller, and the flow rate is controlled at 60-70m 3 / h.

10. A method for stripping a paste resin latex as claimed in claim 1, characterized in that: The vinyl chloride content of the paste resin latex after stripping is less than or equal to 1ppm / 0.1g, and the water content of the latex after stripping is reduced by 55%-57%.

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