A high-efficiency water removal device for vinyl chloride monomer and a high-efficiency water removal method thereof

Abstract

The present invention provides a vinyl chloride monomer efficient water removal device and a method for efficient water removal thereof. In the vinyl chloride monomer efficient water removal device, a coalescing filter element made of polyphenylene sulfide or fluoropolymer is installed in a coalescer, which not only has a stable and reliable water removal effect, but also is effective even when there is a surfactant in the vinyl chloride monomer and the interfacial tension is lower than 3 dyne / cm. The device also has a large coalescing treatment capacity, a small number of coalescing filter elements, a small size of the coalescer, and small equipment investment and operating costs. Furthermore, the vinyl chloride monomer efficient water removal device of the present invention adopts an integrated skid-mounted design, has a high degree of integration, saves space, and is easy to transport and install.

Description

Technical Field

[0001] The invention relates to the technical field of production of vinyl chloride and its polymers, and in particular to a vinyl chloride monomer high-efficiency water removal device and a high-efficiency water removal method. Background Art

[0002] Polyvinyl chloride (PVC) is a thermoplastic resin formed by the polymerization of vinyl chloride under the action of an initiator. It was once the world's largest-volume general-purpose plastic and is widely used. It is widely used in building materials, industrial products, daily necessities, floor tiles, artificial leather, packaging films, bottles, wires and cables, foam materials, fibers, etc.

[0003] In the production process of polyvinyl chloride (PVC), the moisture content in vinyl chloride monomer (VCM) has a great influence on the operation effect of production equipment and the quality of vinyl chloride products. Vinyl chloride hydrolyzes with trace water in the system to generate peroxides, producing acidic corrosive substances such as hydrogen chloride, formic acid, and formaldehyde, thereby corroding metal equipment and generating iron ions. Iron ions will affect the thermal stability of PVC products and the uniformity of resin particles, leading to the generation of black spot impurities, thereby affecting product quality and reducing the market competitiveness of products. In addition, for the production process of polyvinyl chloride by calcium carbide method, iron ions will aggravate the oxidation of vinyl chloride in an environment where hydrogen chloride and water coexist, generate more peroxides, thereby initiating the polymerization reaction of vinyl chloride, and generating polyvinyl chloride with a low degree of polymerization, causing blockage of downstream equipment such as tower components and pipelines, affecting the normal production of the factory, and forcing the factory to be forced to stop for cleaning and maintenance. In this case, it will not only restrict the continuous and stable production of the factory, but also increase a large amount of equipment maintenance costs. In addition, vinyl chloride monomer is toxic, harmful and volatile. Frequent maintenance will not only have a harmful effect on the production environment, but also cause a major hidden danger to the personal safety of maintenance personnel.

[0004] At present, there are mainly the following ways to remove water from vinyl chloride monomer:

[0005] 1. Water separation tank static water removal technology. A small amount of water is dispersed in the vinyl chloride monomer, that is, it exists in the form of droplets of varying sizes. By setting up a large container as a water separation tank in the process route, the flow rate of the vinyl chloride monomer is reduced after entering the water separation tank. By taking advantage of the different densities of water and vinyl chloride monomer, the larger diameter water droplets in the vinyl chloride gradually stratify and settle to the bottom of the water separation tank. The water separation tank static technology can separate larger droplets with a diameter greater than 10 microns.

[0006] 2. Solid alkali drying technology. The solid alkali (main component is NaOH, with a mass fraction of about 97.5%) absorbs trace moisture in the vinyl chloride monomer and then uses the density difference (density of vinyl chloride monomer is 910kg / m 3 , the density of NaOH solution is 1500kg / m3 The absorbed water (in the form of NaOH solution) is separated.

[0007] 3. Pressure swing adsorption dehydration technology (gas phase adsorption). The principle of pressure swing adsorption technology is based on the physical adsorption of gas molecules on the internal surface of the adsorbent (porous solid material). It uses the characteristics of the adsorbent that it is easy to adsorb high-boiling point components under the same pressure, difficult to adsorb low-boiling point components, and the adsorption amount of adsorbed components increases under high pressure and decreases under reduced pressure. The raw gas passes through the adsorbent bed at a certain pressure, and the high-boiling point components such as acetylene, vinyl chloride and carbon dioxide in the raw gas are selectively adsorbed by the adsorbent, and the low-boiling point components such as nitrogen and hydrogen are sent to the subsequent pressure swing hydrogenation device as purified gas. Then, the adsorbed components such as acetylene, vinyl chloride and carbon dioxide are analyzed under reduced pressure, and the analyzed gas (containing acetylene and vinyl chloride) is recycled, and the adsorbent is regenerated at the same time to facilitate the next adsorption separation.

[0008] 4. Traditional coalescer water removal technology. Traditional coalescers generally use coalescing filter elements made of glass fiber, which have poor water removal effects, and when the medium contains surfactants, the coalescing will gradually fail. In addition, the traditional coalescer has a small processing capacity and requires more filter elements and larger containers to meet the process requirements, and the one-time investment and operating costs are high. Traditional coalescer water removal technology generally adopts a split design of pre-filter and coalescer, that is, the scope of supply generally only includes pre-filter and coalescer, and the related pipelines, instrument valves, valves, etc. need to be configured by the user, which will cause problems such as large workload for users, long construction period, and cumbersome installation.

[0009] However, the above vinyl chloride monomer dehydration technologies all have certain defects:

[0010] Disadvantages of the water tank standing technology: For the water tank standing and stratified drainage, only large droplets with a diameter greater than 10 microns can be removed, but liquids with a diameter less than 10 microns cannot be effectively removed in this way. These droplets will form a stable oil-in-water emulsion in the vinyl chloride monomer, and will not settle no matter how long it is left standing, so it cannot be effectively separated. After separation by the water tank standing technology, the water content in the vinyl chloride monomer is still as high as 1500-1800 mg / kg, which cannot effectively improve the quality of downstream products.

[0011] The defects of solid alkali drying and water removal technology: the effect of solid alkali in the early stage of use is acceptable, but in the actual production process, after the solid alkali surface absorbs water, it will form a colloidal high-concentration alkali, and stick together with other solid alkali particles, blocking the accumulation gap flow channel. As the water content of the concentrated alkali increases, it becomes fluid after becoming a dilute alkali, and separates after leaving the solid alkali sedimentation. However, the above process is uneven in the solid alkali bed. Due to the poor stacking density and adhesion effect of the solid alkali bed, the resistance of the bed is uneven. The local part of the bed will soon be penetrated by a large amount of liquid to form a channel flow, which will cause the water-containing vinyl chloride to bypass and penetrate, and the water removal efficiency will be greatly reduced. After solid alkali drying and water removal, the water content in vinyl chloride is still 500-600 mg / kg or higher. Secondly, a small amount of solid alkali will also enter the downstream polymerization process with the vinyl chloride material, which will affect the product quality of the resin. Thirdly, due to the continuous consumption and performance degradation of solid alkali, it is necessary to continuously replace it with new solid alkali. However, the labor intensity of removing waste alkali and replacing it with new one is high. The disposal of waste solid alkali and the replacement of new solid alkali will not only incur a lot of expenses, but also bring great environmental pressure to production enterprises.

[0012] Disadvantages of pressure swing adsorption water removal technology: This technology has a large number of process equipment and occupies a large area. It belongs to gas phase adsorption and uses traditional processes to adsorb condensed water, which requires frequent desorption and regeneration. The pressure swing adsorption water removal effect is good, but the device has high operating resistance, which will increase the load of the vinyl chloride compressor, increase cooling water consumption, high energy consumption, and high operating costs.

[0013] The defects of traditional coalescer water removal technology: 1) The coalescing water removal filter element is made of glass fiber, and the water removal effect is not good; the traditional glass fiber coalescer filter material contains silanol groups with surface active functions. Since silanol is more polar than water, it occupies the glass fiber adsorption point. The silanol groups on the glass fiber have a stronger affinity for surfactants than for water. Vinyl chloride monomer contains a large amount of surfactants (generally detergents, additives or inhibitors, etc.). Therefore, when the vinyl chloride monomer containing water passes through the coalescer, the surfactant molecules will combine with the glass fiber, and the water molecules will quickly pass through the filter material. The water molecules will not coalesce with the glass fiber, which will greatly reduce the water removal efficiency, increase the possibility of product quality problems, shorten the service life of the coalescer, and cause frequent replacement of the filter element and a lot of maintenance work, increasing additional operating costs. 2) The processing capacity of a single coalescing filter element is small, and a large number of coalescing filter elements are required, resulting in a large container volume, a large footprint, and a high cost. 3) The equipment layout is unreasonable, the installation is complicated, and it is not convenient for daily maintenance and repair.

[0014] In summary, it is necessary to develop a new type of vinyl chloride monomer high-efficiency water removal device and a high-efficiency water removal method. Summary of the invention

[0015] In view of the problems existing in the prior art, the present invention provides a device for efficiently removing water from vinyl chloride monomer and a method for efficiently removing water from the device. In the device for efficiently removing water from vinyl chloride monomer, a coalescing filter element made of polyphenylene sulfide or fluoropolymer is installed in the coalescer, which not only has a stable and reliable water removal effect, but also is effective even when there is a surfactant in the vinyl chloride monomer and the interfacial tension is lower than 3 dyne / cm. The device also has the advantages of a large coalescing processing capacity, a small number of coalescing filter elements, a small size of the coalescer, and a small equipment investment and operating cost.

[0016] To achieve this object, the present invention adopts the following technical solutions:

[0017] In the first aspect, the present invention provides a high-efficiency water removal device for vinyl chloride monomer, which comprises a pre-filter and a coalescer connected in series in sequence; the coalescer is equipped with a coalescing filter element made of polyphenylene sulfide or fluoropolymer, and a coalescing water outlet is provided at the bottom of the coalescer for collecting free water after coalescence and separation.

[0018] In the high-efficiency water removal device for vinyl chloride monomer of the present invention, a coalescing filter element made of polyphenylene sulfide or fluoropolymer is installed in the coalescer, which not only has a stable and reliable water removal effect, but also is effective even when there is a surfactant in the vinyl chloride monomer and the interfacial tension is lower than 3 dyne / cm. It also has the advantages of large coalescing processing capacity, small number of coalescing filter elements, small size of coalescer, small equipment investment and operating cost. The high-efficiency water removal device for vinyl chloride monomer of the present invention overcomes the shortcomings of the prior art, can effectively solve the problems of poor water removal effect and high operating cost of vinyl chloride monomer in the existing PVC production process, and can realize the environmental protection and low energy consumption operation of the existing production equipment, and effectively improve the quality of PVC products, and enhance the market competitiveness of enterprises.

[0019] It should be noted that a fluid outlet is opened at the top of the coalescer for collecting the vinyl chloride monomer after dehydration; further preferably, an exhaust port is opened at the top of the pre-filter and the coalescer for discharging excess gas in the fluid, and a sewage outlet is opened at the pre-filter and the coalescer respectively for discharging impurities filtered out.

[0020] As a preferred technical solution of the present invention, the pre-filter includes two pre-filters connected in parallel, and a switching valve is arranged upstream, and the downstream collecting pipeline is connected in series with the coalescer.

[0021] It should be noted that, in order to protect the dewatering effect and service life of the coalescer, two parallel pre-filters are set for the pretreatment of vinyl chloride monomer. On the one hand, they are used to intercept solid particles or a small amount of self-polymers in the vinyl chloride monomer, such as impurities such as rust in the pipeline. On the other hand, they can also initially coalesce large water droplets in the vinyl chloride monomer, thereby enhancing the coalescing effect of the downstream coalescer on trace water in the vinyl chloride monomer. The pre-filter is set in parallel with one on and one off. A switching valve is set between the two pre-filters. When one is in working state, the other is in standby state. When the operating pressure difference of the working pre-filter reaches the set value, the vinyl chloride monomer can be introduced into the other standby filter through the switching valve, and the filter element of the other filter can be replaced and other maintenance can be performed. This can ensure the continuous long-term operation of the device, avoid unplanned shutdowns caused by on-site maintenance, and reduce operation and maintenance costs for enterprises.

[0022] As a preferred technical solution of the present invention, the filter element of the pre-filter is a polypropylene pleated filter element or a stainless steel metal filter element.

[0023] It should be noted that the filter element of the pre-filter of the present invention can be selected according to the on-site working conditions, and a polypropylene pleated filter element with good corrosion resistance is preferred. Since the pleated filter element has a large filtering area and a large dirt holding capacity, it can not only extend the service life of the pre-filter, but also make the container size of the pre-filter smaller, thereby saving costs.

[0024] As a preferred technical solution of the present invention, the filtration accuracy of the pre-filter is 5 to 15 microns, for example, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, 11 microns, 12 microns, 13 microns, 14 microns or 15 microns, etc.

[0025] It should be noted that the filtering accuracy of the pre-filter of the present invention, that is, the filtering accuracy of the pre-filter element, can be reasonably selected according to different on-site working conditions to ensure that the normal operation of the downstream coalescer can be effectively protected.

[0026] As a preferred technical solution of the present invention, the maximum filter material pore size of the coalescing filter element is 10 to 15 microns, such as 10 microns, 11 microns, 12 microns, 13 microns, 14 microns or 15 microns.

[0027] It should be noted that coalescence is the main process of removing water from vinyl chloride monomer, and a coalescence filter element whose main material is polyphenylene sulfide or fluoropolymer is selected. After the pre-filtered vinyl chloride monomer enters the coalescer, vinyl chloride passes through the coalescence filter element from the inside to the outside. At the beginning, the pore size of the filter material is small, and then gradually enlarges, leaving space for the coalesced droplets. The coalescence mechanism of this process: 1. Small droplets are adsorbed by the fiber; 2. With the flow of the fluid, the small droplets are sent to the intersection of the fiber; 3. Two small droplets collide to form a large droplet; 4. Repeat the above process, and the droplets coalesce into larger droplets at the intersection of the fibers; 5. Due to the increase in the drag force of the fluid on the adsorbed droplets, the droplets fall off from the intersection of the fibers; 6. Repeat the above steps 1 to 5, the size of the droplets becomes larger and larger, and the opening of the filter medium becomes larger and larger. Generally, the coalescing filter element includes at least three fiber filter material layers from the inside to the outside, with the filter material pore sizes gradually increasing, and the maximum filter material pore size of the coalescing filter element is the filter material pore size of the outermost fiber filter material layer.

[0028] Generally, there are surfactants in vinyl chloride monomers. Traditional glass fiber filter materials will gradually become ineffective in the presence of surfactants. At the same time, the presence of surfactants will also reduce the interfacial tension between vinyl chloride monomer and water. When the interfacial tension is lower than 20 dynes / cm, it becomes difficult to separate water from vinyl chloride monomer. In the present invention, a coalescing filter element made of polyphenylene sulfide or fluoropolymer material is used, and coalescence failure will not occur. When the interfacial tension is lower than 3 dynes / cm, coalescence is still effective. Therefore, the service life of the coalescer is long, and the water removal effect is stable and reliable. In addition, the coalescing filter element used in the present invention has a larger processing capacity than the traditional glass fiber filter element, so a smaller number of filter elements can meet the process requirements, and the size of the container will also be smaller, and both the one-time investment and the long-term operation cost are low.

[0029] As a preferred technical solution of the present invention, the pre-filter is a vertical pre-filter, and the coalescer is a horizontal coalescer.

[0030] As a preferred technical solution of the present invention, a liquid collecting bag is arranged at the bottom of the coalescer, and the coalesced water outlet is opened at the bottom of the liquid collecting bubble to collect the free water after coalescence and separation; the liquid collecting bag is provided with an on-site boundary meter and / or a remote boundary meter.

[0031] It should be noted that the coalescer adopts a horizontal structure, and the shell is provided with a sedimentation section. The length of the sedimentation section varies depending on the processing volume and process. Relying on the difference in density between vinyl chloride and water, the large water droplets that are coalesced will be separated in the sedimentation area of ​​the coalescer. Since the density of water is greater than that of vinyl chloride, a liquid collecting bag is set at the bottom of the coalescer shell, and the free water after coalescence and separation is gradually collected in the liquid collecting bag at the bottom of the container. An on-site boundary level meter is set in the liquid collecting bag, and the water can be discharged manually and regularly. A remote boundary level meter and an automatic discharge valve can also be set at the same time. When the water level is higher than a certain value, the automatic discharge is started, which can greatly improve the degree of automation of the entire device and save a lot of labor.

[0032] As a preferred technical solution of the present invention, the vinyl chloride monomer high-efficiency water removal device is an integrated skid-mounted design.

[0033] It should be noted that the high-efficiency water removal device for vinyl chloride monomer described in the present invention adopts an integrated skid-mounted design. Different from the traditional structure, the skid-mounted design integrates the pre-filter, coalescer, connecting pipes, valves, instruments, maintenance platform, etc. into a whole. The integrated skid-mounted design can achieve: 1) space saving. Compared with the traditional layout, the skid-mounted design can greatly reduce the footprint of the equipment; 2) strong flexibility. It can be customized according to different usage requirements to meet various special process requirements. Pressure vessels of different specifications and types, as well as supporting equipment and control systems can be selected according to actual conditions. 3) Easy to install and transport. The skid-mounted equipment is assembled and debugged in the factory, and only simple connections and fixations are required on site, which greatly shortens the installation and debugging time of the equipment on the user's site; at the same time, the overall transportation is more convenient and reduces the transportation cost. 4) High reliability. The production environment and quality control in the factory can ensure the reliability and stability of the skid-mounted equipment and reduce the problems that may occur during the user's on-site installation. 5) Easy to maintain and overhaul. The skid-mounted equipment is centrally arranged, which is convenient for daily maintenance and overhaul and improves work efficiency.

[0034] In a second aspect, the present invention provides a method for efficiently removing water from vinyl chloride monomer, using the device for efficiently removing water from vinyl chloride monomer described in the first aspect, the method comprising the following steps:

[0035] The aqueous vinyl chloride monomer is passed through a pre-filter to remove solid particles and to initially agglomerate free water droplets. The pre-filtered aqueous vinyl chloride monomer passes through a coalescer, and the free water separated by agglomeration is collected by a liquid collecting bag at the bottom of the coalescer.

[0036] As a preferred technical solution of the present invention, the pre-filter includes two pre-filters in parallel, and a switching valve is arranged upstream, and the downstream collecting pipeline is connected in series with the coalescer; the switching valve controls the two pre-filters to be in a parallel working state of one on and one on standby, and when the filter element of the pre-filter in the working state needs to be replaced, the pre-filter in the standby working state is switched to the working state by the switching valve.

[0037] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0038] In the high-efficiency water removal device for vinyl chloride monomer described in the present invention, a coalescing filter element made of polyphenylene sulfide or fluoropolymer is installed in the coalescer, which not only has a stable and reliable water removal effect, but also is effective even when there is a surfactant in the vinyl chloride monomer and the interfacial tension is lower than 3 dyne / cm. It also has the advantages of a large coalescing processing capacity, a small number of coalescing filter elements, a small size of the coalescer, and a small equipment investment and operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a process flow chart of the high-efficiency water removal device for vinyl chloride monomer described in Example 1 of the present invention.

[0040] Figure 2 It is a schematic diagram of the three-dimensional structure of the high-efficiency water removal device for vinyl chloride monomer described in Example 1 of the present invention.

[0041] Figure 3 yes Figure 2 Schematic diagram of the three-dimensional structure after removing the maintenance platform.

[0042] In the figure: 1-skid mounted frame, 2-pre-filter, 3-coalescer, 4-inlet pipeline, 5-outlet pipeline, 6-exhaust pipeline, 7-sewage pipeline, 8-coalescing water pipeline. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0044] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0045] Example 1

[0046] This embodiment provides a high-efficiency water removal device and a high-efficiency water removal method for vinyl chloride monomer, such as Figure 1 As shown, the vinyl chloride monomer high-efficiency water removal device comprises a pre-filter 2 and a coalescer 3 which are sequentially connected in series; the coalescer 3 is equipped with a coalescing filter element made of polyphenylene sulfide produced by Pall Corporation, and a coalescing water outlet is provided at the bottom of the coalescer 3 for collecting free water after coalescence and separation;

[0047] The pre-filter 2 includes two pre-filters 2 connected in parallel, and a switching valve is set on the upstream inlet pipeline 4, and the downstream collection pipeline is connected in series with the coalescer 3; the filter element of the pre-filter 2 is a polypropylene pleated filter element; the filtration accuracy of the pre-filter 2 is 10 microns; the maximum filter material pore size of the coalescing filter element is 15 microns; the pre-filter 2 is a vertical pre-filter, and the coalescer 3 is a horizontal coalescer; a liquid collection bag is set at the bottom of the coalescer 3, and the coalescing water outlet is opened at the bottom of the collecting bubble, and the liquid after coalescence and separation is collected through the coalescing water pipeline 8. The water is separated and the coalesced water is treated; the liquid collection bag is provided with an on-site interface meter and a remote interface meter at the same time; a fluid outlet is provided at the top of the coalescer 3, and the vinyl chloride monomer after dehydration is collected through the outlet pipeline 5; exhaust ports are provided at the tops of the pre-filter 2 and the coalescer 3, respectively, and the excess gas in the fluid is discharged through the exhaust pipeline 6; based on the filter element, the pre-filter 2 is divided into two upper and lower cavities, each of which has a sewage outlet at the bottom, and a sewage outlet is provided at the bottom of the coalescer 3, and the sewage outlets of the pre-filter 2 and the coalescer 3 are connected to the sewage main pipe through the sewage pipeline 7; in the following example, Figure 2 and Figure 3 As shown, the vinyl chloride monomer high-efficiency water removal device is an integrated skid-mounted design, that is, the pre-filter 2, the coalescer 3 and the related connecting pipes, valves, instruments, maintenance platforms, etc. are pre-integrated on the skid-mounted frame 1.

[0048] This embodiment also provides a method for efficiently removing water from vinyl chloride monomer, using the aforementioned device for efficiently removing water from vinyl chloride monomer, the method comprising the following steps:

[0049] Set the flow rate to 40m 3 / h of aqueous vinyl chloride monomer enters the pre-filter 2 through the inlet pipeline 4, removes solid particles, and preliminarily coalesces free water droplets; wherein the pre-filter 2 includes two pre-filters 2 connected in parallel, and a switching valve is provided on the upstream inlet pipeline 4, and the downstream aggregation pipeline is connected in series with the coalescer 3; the switching valve controls the two pre-filters to be in a parallel working state of one on and one on standby, and when the filter element of the pre-filter in the working state needs to be replaced, the pre-filter in the standby working state is switched to the working state through the switching valve, and based on the switching valve on the inlet pipeline 4, the aqueous vinyl chloride monomer is promptly introduced into the pre-filter 2 in the working state;

[0050] The aqueous vinyl chloride monomer after pre-filtration enters the coalescer 3, and the coalescing filter element of polyphenylene sulfide installed inside is used to achieve the coalescence of small free water droplets. Based on the density difference between the free water after coalescence and the vinyl chloride monomer, the free water after coalescence settles downward in the sedimentation section of the coalescer and is collected in the liquid collecting bag. The free water after coalescence and separation is discharged in time through the coalescing water pipeline 8 through the on-site boundary meter and the remote boundary meter arranged on the liquid collecting bag, and the coalescing water is treated; during this period, the vinyl chloride monomer after dehydration is collected through the outlet pipeline 5, the excess gas in the fluid is discharged through the exhaust pipeline 6, and the solid particles filtered out of the pre-filter 2 are discharged through the sewage pipeline 7.

[0051] Example 2

[0052] This embodiment provides a high-efficiency water removal device for vinyl chloride monomer and a high-efficiency water removal method thereof. Compared with Embodiment 1, the only difference is that: the coalescer 3 is equipped with a coalescing filter element made of fluoropolymer produced by Pall Corporation; in the high-efficiency water removal method for vinyl chloride monomer, the processing flow rate is still 40m 3 / h of aqueous vinyl chloride monomer.

[0053] Comparative Example 1

[0054] This comparative example provides a high-efficiency water removal device for vinyl chloride monomer and a high-efficiency water removal method thereof. Compared with Example 1, the only difference is that: a coalescing filter element made of glass fiber is installed in the coalescer 3; in the high-efficiency water removal method for vinyl chloride monomer, the processing flow rate is still 40m 3 / h of aqueous vinyl chloride monomer.

[0055] Comparative Example 2

[0056] This comparative example provides a high-efficiency water removal device for vinyl chloride monomer and a high-efficiency water removal method thereof. Compared with Example 1, the only difference is that: a coalescing filter element made of polypropylene fiber is installed in the coalescer 3; in the high-efficiency water removal method for vinyl chloride monomer, the processing flow rate is still 40m 3 / h of aqueous vinyl chloride monomer.

[0057] Comparative Example 3

[0058] This comparative example provides a high-efficiency water removal device for vinyl chloride monomer and a high-efficiency water removal method thereof. Compared with Example 1, the only difference is that: a coalescing filter element made of metal fiber is installed in the coalescer 3; in the high-efficiency water removal method for vinyl chloride monomer, the processing flow rate is still 40m 3 / h of aqueous vinyl chloride monomer.

[0059] The above-mentioned embodiments and comparative examples all process the same batch of aqueous vinyl chloride monomer, the water content of the aqueous vinyl chloride monomer is 3000-5000 ppm, and due to the presence of the surfactant, the interfacial tension of the aqueous vinyl chloride monomer is only about 3 dyne / cm. The timing starts from the time when the coalescing filter element is put into production, and the water content of the vinyl chloride monomer after dehydration is measured after continuous operation for 100 hours; wherein, the free water detection standard is ASTM D3240 Standard Test Method for Insoluble Water in Aviation Turbine Fuel, and the specific test results are summarized in Table 1.

[0060] Table 1

[0061]

[0062] In summary, in the high-efficiency water removal device for vinyl chloride monomer described in the present invention, a coalescing filter element made of polyphenylene sulfide or fluoropolymer is installed in the coalescer, which not only has a stable and reliable water removal effect, but also is effective even when there is a surfactant in the vinyl chloride monomer and the interfacial tension is lower than 3 dyne / cm. It also has the advantages of a large coalescing processing capacity, a small number of coalescing filter elements, a small size of the coalescer, and a small equipment investment and operating cost.

[0063] The key points of the present invention include: 1) the pre-filter element has a large filtering area, high filtering efficiency, long service life, and low spare parts replacement cost. 2) The coalescing filter element uses polyphenylene sulfide or fluoropolymer, which is not affected by surfactants, has no performance loss, and can achieve long-term stable operation. 3) High-performance design, small device size, low cost, and low operation and maintenance costs. 4) Skid-mounted design, high integration, space saving, and easy transportation and installation. 5) High degree of automation, easy for daily maintenance. Through the high-efficiency water removal device for vinyl chloride monomer of the present invention, the free water content in vinyl chloride monomer can be effectively removed to below 20ppm, which can not only effectively protect downstream equipment and extend the service life of equipment, but also improve the quality of PVC products, so that the whiteness of the resin and the uniformity of the particles are significantly improved, thereby achieving cost reduction and efficiency improvement for enterprises, and can also promote the development of the technical level of my country's PVC industry and improve the market competitiveness of resin products. Moreover, since the filter element material selected by the present invention has good water removal performance, high efficiency, and long service life, it can greatly reduce the operating cost for production enterprises.

[0064] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0065] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0067] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A high-efficiency water removal device for vinyl chloride monomer, characterized in that: The high-efficiency water removal device for vinyl chloride monomer comprises a pre-filter and a coalescer connected in series in sequence; the coalescer is equipped with a coalescing filter element made of polyphenylene sulfide or fluoropolymer, and a coalescing water outlet is provided at the bottom of the coalescer for collecting free water after coalescence and separation.

2. The high-efficiency water removal device for vinyl chloride monomer according to claim 1, characterized in that: The pre-filter comprises two pre-filters connected in parallel, and a switching valve is arranged upstream, and a downstream collecting pipeline is connected in series with the coalescer.

3. The high-efficiency water removal device for vinyl chloride monomer according to claim 1 or 2, characterized in that: The filter element of the pre-filter is a polypropylene pleated filter element or a stainless steel metal filter element.

4. The high-efficiency water removal device for vinyl chloride monomer according to claim 1 or 2, characterized in that: The filtering accuracy of the pre-filter is 5 to 15 microns.

5. The high-efficiency water removal device for vinyl chloride monomer according to claim 1, characterized in that: The maximum filter material pore size of the coalescing filter element is 10 to 15 microns.

6. The high-efficiency water removal device for vinyl chloride monomer according to claim 1, characterized in that: The pre-filter is a vertical pre-filter, and the coalescer is a horizontal coalescer.

7. The high-efficiency water removal device for vinyl chloride monomer according to claim 1, characterized in that: A liquid collecting bag is arranged at the bottom of the coalescer, and the coalesced water outlet is opened at the bottom of the liquid collecting bubble to collect the free water after coalescing and separation; the liquid collecting bag is provided with an on-site boundary meter and / or a remote boundary meter.

8. The high-efficiency water removal device for vinyl chloride monomer according to claim 1, characterized in that: The vinyl chloride monomer high-efficiency water removal device is an integrated skid-mounted design.

9. A method for efficiently removing water from vinyl chloride monomer, using the device for efficiently removing water from vinyl chloride monomer according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: The aqueous vinyl chloride monomer is passed through a pre-filter to remove solid particles and to initially agglomerate free water droplets. The pre-filtered aqueous vinyl chloride monomer passes through a coalescer, and the free water separated by agglomeration is collected by a liquid collecting bag at the bottom of the coalescer.

10. The method for efficiently removing water from vinyl chloride monomer according to claim 9, characterized in that: The pre-filter includes two parallel pre-filters, and a switching valve is set upstream, and the downstream collecting pipeline is connected in series with the coalescer; the switching valve controls the two pre-filters to work in parallel with one on and one on standby. When the pre-filter in the working state needs to replace the filter element, the pre-filter in the standby working state is switched to the working state through the switching valve.

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