CN217526426U - Monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment process - Google Patents
Monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment process Download PDFInfo
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- CN217526426U CN217526426U CN202221070125.8U CN202221070125U CN217526426U CN 217526426 U CN217526426 U CN 217526426U CN 202221070125 U CN202221070125 U CN 202221070125U CN 217526426 U CN217526426 U CN 217526426U
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Abstract
The utility model relates to a chloroethylene rectification monomer advanced treatment process recovery monomer refining device, which comprises a recovery monomer pipeline, a solid alkali dryer automatic control valve, a coarse monomer storage tank automatic control valve, a fine monomer storage tank automatic control valve, a waste alkali liquid pipe, an alkali pump automatic control valve, an alkali pump, an alkali collection tank liquid level transmitter, an alkali collection tank pressure transmitter, a chloroethylene recovery pipe, a hot water return pipe, a hot water feeding pipe and an alkali collection tank alkali outlet valve; the alkali collecting tank is used as a connecting center, and a liquid level transmitter and a pressure transmitter of the alkali collecting tank are arranged on the alkali collecting tank; wherein the alkali collecting tank pressure transmitter is dual redundant; the alkali pump is arranged at the outlet end of the alkali collecting tank; the export of alkali pump is provided with alkali pump automatic control valve to connect the waste alkali liquid pipe to send alkali to the water alkali wash process alkali jar, the blowdown flow is relatively stable, and the system operates steadily, has reduced intensity of labour, has realized full automation, has improved work efficiency and fail safe nature.
Description
Technical Field
The utility model relates to a vinyl chloride rectification monomer advanced treatment technology technical field, especially a monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment technology.
Background
In the suspension method polyvinyl chloride (PVC) production process, in order to ensure the quality of a polyvinyl chloride product and the service efficiency of a polymerization kettle, the conversion rate of a Vinyl Chloride Monomer (VCM) is generally controlled to be 80-85%, and at present, most domestic polyvinyl chloride enterprises adopt the United states Goodrich monomer recovery technology to recover unreacted monomers through compression and condensation. The recovered monomer and the fresh monomer are added into the polymerization kettle again according to a certain proportion for reaction. Because the recovered monomer contains high-boiling-point substances, water and auxiliary agent residues, some chemical production industries adopt solid alkali drying technology to remove the high-boiling-point substances, the water and the residual auxiliary agent in the recovered monomer. The process mainly comprises the steps of dehydrating a vinyl chloride recovered monomer obtained after polymerization, compression and condensation by a solid alkali drier, removing a large amount of water and auxiliary agent residues, then feeding the dehydrated monomer into a crude monomer storage tank, pumping the monomer into a high-boiling tower by a crude monomer pump for distillation, distilling vinyl chloride gas out of the tower top, condensing the vinyl chloride gas by a condenser, and then feeding the vinyl chloride gas into a refined monomer storage tank; the refined recovered monomer is pumped by a pump to be polymerized and added into a polymerization kettle according to a certain proportion to react again with fresh monomer. And discharging the residual liquid in the tower bottom into a residual liquid storage tank of a rectification system, and fractionating the chloroethylene in the residual liquid storage tank by a rectification three tower for sale. In the whole process, a solid alkali dryer discharges sewage, a coarse and fine monomer storage tank discharges sewage, and the waste liquid is discharged into an alkali collecting tank to evaporate chloroethylene therein and then is pumped out to a water alkali washing tower for alkali preparation. The following problems currently exist:
1. because the solid caustic soda dryer uses solid caustic soda as initial spherical caustic soda, the solid caustic soda dryer uses the solid caustic soda to replace the initial spherical caustic soda into cheaper and easily-obtained flake caustic soda due to higher manufacturing cost, no manufacturers and the like; due to the characteristics of flake caustic soda, pollution discharge must be carried out every hour in the use process of a solid caustic soda dryer, if the pollution discharge is not carried out on time, the water content in the solid caustic soda dryer rises, a vicious circle is formed, long-time pollution discharge is insufficient, and in addition, the pollution discharge of a coarse monomer storage tank and a fine monomer storage tank is not timely, the vinyl chloride recovery monomer is brought with caustic soda, once the recovery monomer contains a large amount of alkali liquor, a polyvinyl chloride dispersant system is damaged, and finally coarse materials are generated;
2. the operator can increase the operation intensity of the operator by regularly discharging the sewage;
3. the method for regularly discharging the sewage by setting the DCS cannot be matched with the pressure and liquid level parameters of the recovery system;
4. chloroethylene is flammable and explosive, has strong pollution, and can generate potential safety hazards when being treated improperly, so the pressure is one of the most key control indexes.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment technology to solve among the prior art operating personnel blowdown, system load increase, influence product quality and have the problem of potential safety hazard, specifically be applicable to and retrieve monomer refining plant, through redundant pressure and liquid level control method, alleviate operating strength, safe and reliable's recovery monomer refining plant.
The utility model provides a technical scheme that its technical problem adopted is: a vinyl chloride rectification monomer advanced treatment process recovery monomer refining device comprises a recovery monomer pipeline, a solid alkali dryer self-control valve, a coarse monomer storage tank self-control valve, a refined monomer storage tank self-control valve, a waste alkali liquid pipe, an alkali pump self-control valve, an alkali pump, an alkali collection tank liquid level transmitter, an alkali collection tank pressure transmitter, a vinyl chloride recovery pipe, a hot water return pipe, a hot water feeding pipe and an alkali outlet valve of the alkali collection tank which are sequentially connected; the solid caustic dryer, the coarse monomer storage tank and the fine monomer storage tank are connected with an alkali collecting tank pipeline, and an automatic control valve of the solid caustic dryer, an automatic control valve of the coarse monomer storage tank and an automatic control valve of the fine monomer storage tank are arranged among the solid caustic dryer, the coarse monomer storage tank and the fine monomer storage tank; the alkali collecting tank is used as a connecting center, and a liquid level transmitter and a pressure transmitter of the alkali collecting tank are arranged on the alkali collecting tank; wherein the alkali collecting tank pressure transmitter is dual redundant; the alkali pump is arranged at the outlet end of the alkali collecting tank; and an outlet of the alkali pump is provided with an alkali pump automatic control valve 9 and is connected with a waste alkali liquid pipe to an alkali tank in the water alkali washing process to deliver alkali.
The alkali collecting tank is provided with a hot water return pipe, a hot water feeding pipe, an alkali collecting tank liquid level transmitter and an alkali collecting tank pressure transmitter. And a pressure transmitter is arranged to be either dual-redundant or one, and then the pressure transmitter and the liquid level transmitter are arranged to be either dual-redundant or one, so that the safety precision and the reliability are ensured.
And the alkali collecting tank pressure transmitter is arranged at the top of the alkali collecting tank and is at least provided with 2 alkali collecting tanks. The pressure transmitter is arranged to be either dual-redundant or one of the pressure transmitter and the liquid level transmitter, so that the safety precision and the reliability are ensured.
The liquid level transmitter of the alkali collecting tank is arranged on the cylinder wall of the alkali collecting tank; and a pressure transmitter is arranged to be either dual-redundant or one of the pressure transmitter and the liquid level transmitter, so that the safety precision and the reliability are ensured.
And the vinyl chloride recovery pipe is arranged at the top of the alkali collecting tank and is connected with a vinyl chloride gas holder.
Preferably, the pressure and the liquid level of each tank, the state of the automatic control valve and the opening and closing of the automatic control valve are connected with a DCS control system. The operation is more convenient, safe and reliable.
Preferably, the alkali pump is stopped, and the inlet and outlet valves of the alkali pump, the automatic control valves of the alkali pump, the alkali outlet valves of the alkali collecting tank and the automatic control valves of the outlets of the tanks are interlocked to a DCS control system. In order to prevent the solid alkali dryer, the crude monomer storage tank and the refined monomer storage tank from being started during the operation of the alkali pump, all the blowdown pneumatic valves are kept in a closed state during the operation of the alkali pump until the alkali pump is stopped and the inlet and outlet valves of the alkali pump are closed, and the blowdown process can be carried out.
Compared with the prior art, the utility model provides a monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment technology, in order to prevent a large amount of monomers from discharging into the alkali collection groove, increase recovery system load, set up by DCS control system solid alkali desicator, thick monomer storage tank, refined monomer storage tank carry out the blowdown in proper order, can not blowdown simultaneously; setting dual redundancy of a pressure control loop of the alkali collecting tank, and closing a blowdown valve, an automatic control valve of a solid alkali dryer, an automatic control valve of a coarse monomer storage tank and an automatic control valve of a fine monomer storage tank when the pressure reaches one set value; the pressure and the liquid level of the alkali collecting tank and the blow-down valve are arranged to form a two-out-of-one control loop, namely, the blow-down valve is closed when one of the pressure or the liquid level reaches a set value, and the pressure transmitter display and the liquid level transmitter display of the alkali collecting tank, the automatic control valve and the states of all the tanks are displayed to the DCS control system. The device has the advantages of reducing the operating frequency of operators, ensuring stable discharge capacity, reducing the labor intensity, reducing the number of devices added, along with simple structure, realizing full-automatic operation and improving the working efficiency and the safety and reliability.
Drawings
Fig. 1 is a schematic view of the device of the present invention.
In fig. 1: 1 is a recovered monomer pipeline; 2 is a solid caustic soda dryer; 3 is a solid caustic soda dryer automatic control valve; 4 is a crude monomer storage tank; 5 is a coarse monomer storage tank automatic control valve; 6 is a fine monomer storage tank; 7 is a refined monomer storage tank automatic control valve; 8 is a waste alkali liquor pipe; 9 is an alkali pump automatic control valve; 10 is an alkali pump; 11 is a liquid level transmitter of the alkali collecting tank; 12 is an alkali collecting tank; 13 is a pressure transmitter of the alkali collecting tank; 14 is a chloroethylene recovery pipe; 15 is a hot water return pipe; 16 is a hot water feeding pipe; and 17 is an alkali outlet valve of the alkali collecting tank.
Detailed Description
As shown in fig. 1, a refining device for monomers recycled by a vinyl chloride rectification monomer advanced treatment process comprises a recycled monomer pipeline 1, a solid alkali dryer 2, a solid alkali dryer automatic control valve 3, a crude monomer storage tank 4, a crude monomer storage tank automatic control valve 5, a refined monomer storage tank 6, a refined monomer storage tank automatic control valve 7, a waste alkali liquid pipe 8, an alkali pump automatic control valve 9, an alkali pump 10, an alkali collection tank liquid level transmitter 11, an alkali collection tank 12, an alkali collection tank pressure transmitter 13, a vinyl chloride recycling pipe 14, a hot water return pipe 15, a hot water feeding pipe 16 and an alkali collection tank alkali outlet valve 17 which are connected in sequence; the solid caustic soda dryer 2, the coarse monomer storage tank 4 and the fine monomer storage tank 6 are connected with the caustic soda collecting tank 12 through pipelines, and the automatic control valve 3 of the solid caustic soda dryer, the automatic control valve 5 of the coarse monomer storage tank and the automatic control valve 7 of the fine monomer storage tank are arranged among the solid caustic soda dryer, the coarse monomer storage tank and the fine monomer storage tank; the alkali collecting tank 12 is taken as a connecting center, and is provided with an alkali collecting tank liquid level transmitter 11 and an alkali collecting tank pressure transmitter 13; wherein the caustic sump pressure transmitter 13 is dual redundant; the alkali pump 10 is arranged at the outlet end of the alkali collecting tank 12; the outlet of the alkali pump 10 is provided with an alkali pump automatic control valve 9 and is connected with a waste alkali liquid pipe 8 to an alkali tank in the water alkali washing procedure for conveying alkali.
The difference of another embodiment is that the alkali collecting tank 12 is provided with a hot water return pipe 15, a hot water feeding pipe 16, an alkali collecting tank liquid level transmitter 11 and an alkali collecting tank pressure transmitter 13. And a pressure transmitter 13 is arranged for dual redundancy, and then the pressure transmitter and the liquid level transmitter 11 are arranged for dual redundancy, so that the safety precision and the reliability are ensured.
The difference of another embodiment is that the alkali collecting tank pressure transmitter 13 is arranged on the top of the alkali collecting tank 12, and at least 2 alkali collecting tanks are arranged. One of the dual redundancy alternatives of the pressure transmitter 13 is provided, and then the liquid level transducer 11 is selected alternatively, so that the safety precision and the reliability are ensured.
The difference of the other embodiment is that the alkali collecting tank liquid level transmitter 11 is arranged on the cylinder wall of the alkali collecting tank 12; a double redundancy alternative of the pressure transmitter 13 is provided, and then the liquid level transmitter 11 is selected to be one of the two, so that the safety precision and the reliability are ensured.
The difference of another embodiment is that the vinyl chloride recycling pipe 14 is arranged at the top of the alkali collecting tank 12 and connected with a vinyl chloride gas holder.
Preferably, another embodiment is different in that the tank pressures and liquid levels, the automatic control valve states and the opening and closing are all connected with a DCS control system. The operation is more convenient, safe and reliable.
Preferably, the difference of another embodiment is that the alkali pump 10 is stopped, and the inlet and outlet valves of the alkali pump 10, the alkali pump automatic control valve 9, the alkali outlet valve 17 of the alkali collecting tank and each tank outlet automatic control valve are interlocked to the DCS control system. In order to prevent the solid alkali dryer 2, the coarse monomer storage tank 4 and the fine monomer storage tank 6 from starting the sewage disposal system during the operation of the alkali pump 10, all the sewage disposal pneumatic valves are kept in a closed state during the operation of the alkali pump until the alkali pump 10 stops and the inlet and outlet valves of the alkali pump 10 are closed, so that the sewage disposal procedure can be carried out.
Compared with the prior art, the utility model provides a monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment technology, in order to prevent a large amount of monomers from discharging into the alkali collection groove, increase recovery system load, set up by DCS control system solid alkali desicator 2, thick monomer storage tank 4, refined monomer storage tank 6 carry out the blowdown in proper order, can not blowdown simultaneously; setting dual redundancy of a pressure control loop of the alkali collecting tank 12, and closing the blowdown valve, the solid alkali dryer automatic control valve 3, the coarse monomer storage tank automatic control valve 5 and the fine monomer storage tank automatic control valve 7 when the pressure reaches one set value; the pressure and the liquid level of the alkali collecting tank 12 and the blow-down valve are arranged to form a two-out-of-one control loop, namely, the blow-down valve is closed when one of the pressure or the liquid level reaches a set value, the pressure transmitter 13 of the alkali collecting tank 12 displays the state of the automatic control valve and the states of all the tanks to the DCS control system, and the liquid level transmitter 11 displays the state of all the automatic control valves and all the tanks. The device has the advantages of reducing the operating frequency of operators, ensuring stable discharge capacity, reducing the labor intensity, reducing the number of devices added, along with simple structure, realizing full-automatic operation and improving the working efficiency and the safety and reliability.
The working process comprises the following steps:
according to the utility model discloses the structural feature of device, now carry out the following description to the working process of this device: the utility model provides a monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment technology, for realizing automatic control, set up solid caustic soda desicator 2, thick monomer storage tank 4, 6 bottom blowoff valves of smart monomer storage tank into the automatic control trip valve, increase the automatic module that opens of alkaline pump, the valve all sets up the automatic control trip valve is imported and exported to alkaline pump 10. The control scheme of the refining process of the recovered monomers is as follows: the solid alkali dryer 2, the coarse monomer storage tank 4 and the fine monomer storage tank 6 are used for discharging sewage in sequence, a certain interval time is set in the middle as the recovery time of the alkali collecting tank 12, and vinyl chloride monomer in waste alkali liquor is recovered; in the sewage disposal process, in order to prevent the overflow of the tank, a certain liquid level of the alkali collecting tank 12 is set, and the sewage disposal valve is closed for recycling after a set value is reached. In order to prevent a large amount of monomers from being discharged into the alkali collecting tank 12 and increase the load of a recovery system, the pressure control loop of the alkali collecting tank 12 is provided with dual redundancy, and when the pressure reaches a set value, a sewage discharge valve is closed. The pressure and the liquid level and the blow-down valve form a two-out-of-one control loop, namely, when one of the pressure or the liquid level reaches a set value, the blow-down valve is closed, and three solid caustic soda dryers 2, a coarse monomer storage tank 4 and a fine monomer storage tank 6 are arranged to sequentially blow down.
The opening conditions of the drain valve solid caustic soda dryer automatic control valve 3, the coarse monomer storage tank automatic control valve 5 and the fine monomer storage tank automatic control valve 7 are that the pressure and the liquid level must be less than a set value to carry out sewage discharge, when the temperature or the pressure is greater than the set value, the drain valve cannot be opened to carry out sewage discharge, and a 'fault of a sewage discharge system' pops up on a DCS picture, please check the 'character', and the sewage discharge operation can be carried out after contacting with field personnel to remove the fault.
When the liquid level reaches the set value of high limit, the recovery of the alkali collecting tank 12 is completed (the pressure is set to be low limit, once the recovery pressure or the liquid level is lower than the set value, the recovery is considered to be completed), the system automatically opens the inlet and outlet valves of the alkali pump 10, starts the alkali pump 10 to send alkali to the water alkali washing tank through the waste alkali liquid pipe 8, stops the alkali pump when the liquid level reaches the set low limit value of the alkali tank, and closes the inlet and outlet valves of the alkali pump 10. In order to prevent the solid alkali dryer 2, the coarse monomer storage tank 4 and the fine monomer storage tank 6 from starting the sewage disposal system during the operation of the alkali pump 10, all the sewage disposal pneumatic valves are kept in a closed state during the operation of the alkali pump until the alkali pump 10 stops and the inlet and outlet valves of the alkali pump 10 are closed, so that the sewage disposal procedure can be carried out.
Claims (7)
1. A vinyl chloride rectification monomer advanced treatment technology retrieves monomer refining plant which characterized in that: the refining device comprises a recovered monomer pipeline, a solid alkali dryer automatic control valve, a coarse monomer storage tank automatic control valve, a fine monomer storage tank automatic control valve, a waste alkali liquid pipe, an alkali pump automatic control valve, an alkali pump, an alkali collection tank liquid level transmitter, an alkali collection tank pressure transmitter, a vinyl chloride recovery pipe, a hot water return pipe, a hot water feeding pipe and an alkali collection tank outlet valve which are connected in sequence; the solid caustic dryer, the coarse monomer storage tank and the fine monomer storage tank are connected with an alkali collecting tank pipeline, and an automatic control valve of the solid caustic dryer, an automatic control valve of the coarse monomer storage tank and an automatic control valve of the fine monomer storage tank are arranged among the solid caustic dryer, the coarse monomer storage tank and the fine monomer storage tank; the alkali collecting tank is taken as a connecting center, and a liquid level transmitter and a pressure transmitter of the alkali collecting tank are arranged on the alkali collecting tank; wherein the alkali collecting tank pressure transmitter is dual redundant; the alkali pump is arranged at the outlet end of the alkali collecting tank; and an outlet of the alkali pump is provided with an alkali pump automatic control valve and is connected with a waste alkali liquor pipe to an alkali tank in the water alkali washing process to deliver alkali.
2. The refining plant of claim 1, wherein the alkali collection tank is provided with a hot water return pipe, a hot water supply pipe, an alkali collection tank liquid level transmitter, and an alkali collection tank pressure transmitter; and a pressure transmitter is arranged to perform double redundancy or one selection, and then the pressure transmitter is connected with the liquid level transmitter or one selection.
3. The refining plant of claim 1, wherein the pressure transmitter of the alkali collection tank is arranged at the top of the alkali collection tank and comprises at least 2 units; and setting one of the pressure transmitter and the liquid level transmitter for dual redundancy.
4. The refining device of the recycled monomers in the vinyl chloride rectification monomer advanced treatment process of claim 1, wherein the alkali collecting tank liquid level transmitter is arranged on the cylinder wall of the alkali collecting tank; and setting one of the pressure transmitter and the liquid level transmitter for dual redundancy.
5. The refining plant of claim 1, wherein the vinyl chloride recovery pipe is disposed at the top of the alkali collection tank and connected to the vinyl chloride gas holder.
6. The apparatus of claim 1, wherein the pressure and level of each tank, the status of the automatic control valve, and the opening and closing of the automatic control valve are connected to a DCS control system.
7. The refining plant for recycling monomers in the vinyl chloride rectification monomer advanced treatment process of claim 1, wherein the alkali pump is stopped, the inlet and outlet valves of the alkali pump are interlocked with the alkali outlet valve of the alkali collecting tank and the outlet automatic control valves of each tank to a DCS control system; and during the operation of the alkali pump, all the blowdown pneumatic valves are kept in a closed state until the alkali pump stops and the blowdown program can be carried out after the inlet and outlet valves of the alkali pump are closed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221070125.8U CN217526426U (en) | 2022-05-07 | 2022-05-07 | Monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221070125.8U CN217526426U (en) | 2022-05-07 | 2022-05-07 | Monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment process |
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| Publication Number | Publication Date |
|---|---|
| CN217526426U true CN217526426U (en) | 2022-10-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221070125.8U Active CN217526426U (en) | 2022-05-07 | 2022-05-07 | Monomer refining plant is retrieved to vinyl chloride rectification monomer advanced treatment process |
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| CN (1) | CN217526426U (en) |
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2022
- 2022-05-07 CN CN202221070125.8U patent/CN217526426U/en active Active
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