A coalescence method for removing CPMABA from PPS brine

Abstract

The application discloses a coalescence technology for removing CPMABA in PPS brine, and comprises the following steps: S1, taking PPS brine containing CPMABA, and adjusting the pH value of the PPS brine to be acidic to obtain pretreated PPS brine; and S2, passing the pretreated PPS brine into a coalescence device to perform coalescence treatment. The coalescence technology can efficiently and stably remove the CPMABA impurities in the PPS brine, and improves the quality of the by-product salt.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyphenylene sulfide, and in particular to a coalescence method for removing CPMABA from PPS brine. BACKGROUND

[0002] PPS (polyphenylene sulfide resin) is a widely used polymer material, which has excellent flame retardant performance, thermal stability and chemical corrosion resistance, and has been successfully applied in the fields of electronics, electrical appliances, automobiles, aerospace, etc. In the production process of PPS, a large amount of oily substances will be precipitated from the by-product salt solution. The oily substance is a small molecule aromatic amine compound, and the main component is chlorophenyl methyl amino butyric acid (CPMABA). The CPMABA flocculation will block the resin column of the downstream adsorption device, reduce the effect of removing organic matter by adsorption, and ultimately affect the TOC of the by-product salt, which cannot meet the requirements of other supply chains. Therefore, it is very important to find a fast and efficient method for removing CPMABA.

[0003] Studies have shown that the coalescence method can effectively separate the oily substances in water, and the coalescence filter element with a unique structure is the key to coalescence separation. The principle of the coalescer separation is that the emulsion phase first enters the nanoscale fiber demulsification layer for demulsification, and then the fluid enters the fiber flow channel for gradual coalescence. Before the liquid leaves the outermost layer of the coalescence filter element, the relatively coarse outer coalescence filter material maximizes the size of the coalesced dispersed phase droplets, thereby completing the entire coalescence process, and finally achieving complete separation through gravity settling or separation filter element.

[0004] However, at present, there is no coalescence method for removing CPMABA from PPS brine. SUMMARY

[0005] In view of the above problems existing in the prior art, the present application discloses a coalescence method for removing CPMABA from PPS brine, which can efficiently and stably remove CPMABA impurities in PPS brine and improve the quality of by-product salt.

[0006] The specific technical solution is as follows:

[0007] A coalescence method for removing CPMABA from PPS brine, comprising the following steps:

[0008] S1, taking PPS brine containing CPMABA, and adjusting the pH value of the PPS brine to be acidic to obtain pretreated PPS brine;

[0009] S2, passing the pretreated PPS brine into a coalescence device for coalescence treatment.

[0010] The application discloses a pretreatment of PPS salt solution containing CPMABA by-produced in a polymerization process in PPS production, and then carries out coalescence treatment on the pretreated PPS brine through a coalescence device, so that the CPMABA impurities in the PPS brine can be efficiently and stably removed, and the quality of the by-produced salt is improved.

[0011] PPS and sodium chloride are generated in a polymerization reaction, solid-liquid separation is carried out through a centrifuge, PPS is further treated, and brine is evaporated into salt, and trace CPMABA in the brine is removed before evaporation into salt, the CPMABA is a by-product in the PPS polymerization process. The content of CPMABA in the PPS brine generated when a quenching process is adopted in the polymerization reaction is about 300-400 ppm; and the content of CPMABA in the PPS brine generated when a flash evaporation process is adopted in the polymerization reaction is about 2000-3000 ppm. The coalescence method disclosed by the application can effectively treat the PPS brine generated by the above different processes, and can also treat the PPS brine generated by the above different processes after mixing.

[0012] The coalescence device adopted in the application is a commercially available product, can be a small vertical coalescence device for small-scale test, or a large horizontal coalescence device for large-scale production.

[0013] The main component in the coalescence device is a filter core, and experiments show that the coalescence method of the application preferably adopts polypropylene-phenolic resin composite material (PP-PF) and / or polypropylene-amino fiber composite material (PP-AF), and further preferably adopts PP-PF material.

[0014] The pretreatment process of step S1 is optimized in the application, on the one hand, the PPS brine containing CPMABA is adjusted to be acidic, and on the other hand, the PPS brine is preheated; experiments show that the removal rate of CPMABA impurities in the PPS brine can be improved after the above optimization.

[0015] Preferably, the pH value of the PPS brine containing CPMABA is adjusted to 3-5; further preferably 3-4.

[0016] Preferably, the PPS brine containing CPMABA is heated to 60-90 DEG C; further preferably 80-90 DEG C, and more preferably 80 DEG C.

[0017] Preferably:

[0018] In step S2, the pretreated PPS brine is first pre-filtered, and then introduced into the coalescence device for coalescence treatment.

[0019] It is found through experiments that the removal rate of CPMABA impurities in PPS brine can be further improved by pre-filtering the pretreated PPS brine before coalescing treatment.

[0020] The pre-filtering refers to filtering the pretreated PPS brine through a filter, and the filter core in the filter is preferably used for pre-filtering, and the filter core has a pore size of ≤1 μm.

[0021] The conventional horizontal coalescer on the market includes an inlet valve, a multi-stage filter core, an upper oil collection bag and an outlet valve. It is found through experiments that the removal rate of CPMABA impurities in PPS brine can be further improved by installing a lower oil collection bag in the conventional horizontal coalescer.

[0022] The oil collection bag in the application is used for collecting oil phase and as a buffer tank for oil phase, and a conventional structure is adopted. The upper oil collection bag refers to the oil collection bag arranged above the horizontal coalescer, and the lower oil collection bag refers to the oil collection bag arranged below the horizontal coalescer.

[0023] Compared with the prior art, the application has the following advantages:

[0024] The application discloses a coalescence separation technology, and CPMABA impurities in PPS brine produced in a PPS production polymerization process can be efficiently removed through optimization of a process and improvement of equipment, the resin adsorption effect is improved, and the quality of the salt is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The figure is a process flow diagram of the coalescence method for removing CPMABA in PPS brine in Example 9;

[0026] Figure 2 The figure is a process flow diagram of the coalescence method for removing CPMABA in PPS brine in Example 10;

[0027] Figure 3 The figure is a process flow diagram of the coalescence method for removing CPMABA in PPS brine in Example 11;

[0028] In the figure, 1 is a salt solution transfer tank, 2 is a hydrochloric acid metering tank, 3 is a static mixer, 4 is a horizontal coalescer, 5 is a sampling port, and 6 is a filter.

[0029] 41 is a multi-stage filter core, 42 is an upper oil collection bag, 43 is an outlet valve, and 44 is a lower oil collection bag. DETAILED DESCRIPTION

[0030] For a further understanding of the present application, specific embodiments thereof are described in detail below along with accompanying drawings. The present application is not limited to these embodiments, and non-essential improvements and adjustments made by those skilled in the art under the guidance of the core idea of the present application still belong to the protection scope of the present application.

[0031] Example 1

[0032] S1, 10L of PPS salt solution wastewater containing CPMABA produced in a polymerization process was taken, hydrochloric acid was added to adjust the pH of the wastewater to 3-4, and pretreated wastewater was obtained;

[0033] S2, the pretreated wastewater was passed through a peristaltic pump and into a filter for prefiltration, and a 1 μm GF (glass fiber) filter element was used in the filter;

[0034] S3, assemble the coalescing device, connect the feed tank with pipes, and check the airtightness of the device; pass the pre-filtered wastewater into a vertical coalescer, and use a PP-PF filter element for coalescence; open the lower end inlet valve and the tail end upper exhaust valve of the vertical coalescer, and adjust the speed by peristaltic pump, when the wastewater is about to fill the cavity of the vertical coalescer, close the inlet valve, open the lower end discharge valve, and run the test at a stable flow rate;

[0035] S4, stabilize the filtration for a period of time, and test the oil content of the outlet liquid at the tail end of the vertical coalescer.

[0036] By liquid chromatography test, the CPMABA content in the PPS salt solution wastewater containing CPMABA used in step S1 is 338 ppm, and the CPMABA content in the outlet liquid after step S4 treatment is 207 ppm, and the oil removal efficiency is 38.75%.

[0037] Example 2

[0038] The production process is basically the same as in Example 1, the only difference is that the filter element in step S3 is replaced by PP-AF material.

[0039] By test, the CPMABA content in the outlet liquid after step S4 treatment of the present embodiment is 290 ppm, and the oil removal efficiency is 18.64%.

[0040] Example 3

[0041] The production process is basically the same as in Example 1, the only difference is that the PPS salt solution wastewater containing CPMABA in step S1 is first heated to 80℃, and then the pH value is adjusted.

[0042] By test, the CPMABA content in the outlet liquid after step S4 treatment of the present embodiment is 115 ppm, and the oil removal efficiency is 65.98%.

[0043] Example 4

[0044] The production process is basically the same as in Example 2, except that the CPMABA-containing PPS salt solution wastewater in step S1 is first heated to 80°C, and then the pH value is adjusted.

[0045] After testing, the CPMABA content in the outlet liquid treated by step S4 of this example is 156 ppm, and the oil removal efficiency is 53.84%.

[0046] Example 5

[0047] The production process is basically the same as in Example 3, except that the heating temperature of the CPMABA-containing PPS salt solution wastewater in step S1 is replaced to 60°C.

[0048] After testing, the CPMABA content in the outlet liquid treated by step S4 of this example is 165 ppm, and the oil removal efficiency is 51.18%.

[0049] Example 6

[0050] The production process is basically the same as in Example 3, except that the heating temperature of the CPMABA-containing PPS salt solution wastewater in step S1 is replaced to 90°C.

[0051] After testing, the CPMABA content in the outlet liquid treated by step S4 of this example is 142 ppm, and the oil removal efficiency is 57.99%.

[0052] Example 7

[0053] The production process is basically the same as in Example 3, except that the pH of the wastewater in step S1 is adjusted to 5.

[0054] After testing, the CPMABA content in the outlet liquid treated by step S4 of this example is 137 ppm, and the oil removal efficiency is 59.47%.

[0055] Example 8

[0056] The production process is basically the same as in Example 3, except that the pre-filtering step is not performed, i.e. the pretreated wastewater is directly introduced into the vertical coalescer.

[0057] After testing, the CPMABA content in the outlet liquid treated by this example is 140 ppm, and the oil removal efficiency is 58.58%.

[0058] Comparative Example 1

[0059] The production process is basically the same as in Example 1, except that the wastewater is not pretreated, i.e. the CPMABA-containing PPS salt solution wastewater is directly subjected to the pre-filtering step.

[0060] The content of CPMABA in the outlet liquid after the step S4 of the present comparative example was 310 ppm, and the oil removal efficiency was 8.28%.

[0061] Comparative Example 2

[0062] The production process was basically the same as in Comparative Example 1, except that the filter core in step S3 was replaced by PP-AF material.

[0063] The content of CPMABA in the outlet liquid after the step S4 of the present comparative example was 316 ppm, and the oil removal efficiency was 6.51%.

[0064] Comparative Example 3

[0065] The production process was basically the same as in Comparative Example 1, except that the filter core in step S3 was replaced by SHBPP (polypropylene / carbon fiber composite material) material.

[0066] The content of CPMABA in the outlet liquid after the step S4 of the present comparative example was 330 ppm, and the oil removal efficiency was 2.4%.

[0067] Comparative Example 4

[0068] S1, 10 L of PPS salt solution wastewater containing CPMABA by-produced in the polymerization process of PPS production was heated to 80°C to obtain pretreated wastewater;

[0069] Steps S2-S4 were the same as in Example 1.

[0070] The content of CPMABA in the outlet liquid after the step S4 of the present comparative example was 285 ppm, and the oil removal efficiency was 15.68%.

[0071] Comparative Example 5

[0072] The production process was basically the same as in Comparative Example 4, except that the filter core in step S3 was replaced by PP-AF material.

[0073] The content of CPMABA in the outlet liquid after the step S4 of the present comparative example was 302 ppm, and the oil removal efficiency was 10.65%.

[0074] Example 9

[0075] The present example used a conventional horizontal coalescer, and the process flow diagram of the specific coalescing method is shown in Figure 1

[0076] ​The process flow diagram includes a salt solution transfer tank 1, a hydrochloric acid metering tank 2, a static mixer 3, and a horizontal coalescer 4; the various devices are connected by sealed pipes, and all devices and pipes are insulated with hot water; a sampling port 5 is provided on the pipe connecting the static mixer 3 and the horizontal coalescer 4.

[0077] The horizontal coalescer 4 includes, in sequence along the feed direction, a multi-stage filter element 41, an upper oil collection bag 42, and an outlet valve 43; the multi-stage filter element 41 uses a PP-PF filter element.

[0078] S1. Install the horizontal coalescer, according to... Figure 1 The process flow diagram is used for on-site piping, and 80℃ hot water is used for insulation.

[0079] S2. PPS salt solution wastewater containing CPMABA, a by-product of the polymerization process in PPS production, and hydrochloric acid are injected into static mixer 3 through salt solution transfer tank 1 and hydrochloric acid metering tank 2, respectively, and the pH of the wastewater is adjusted to 3~4.

[0080] S3. Open the feed valve of the horizontal coalescer 4 to control the flow rate to 0.3 m³ / s. 3 / h;

[0081] S4. Open sampling port 5, take 200g of raw water, and send the sample to test the CPMABA concentration in the saline solution;

[0082] S5. Maintain stable operation of the coalescence unit for 48 hours;

[0083] S6. Open the drain port of the upper oil collection bag 42 and the outlet valve 43, and take samples to test the CPMABA content in the liquid in the upper oil bag and the outlet liquid after coalescence.

[0084] To prevent CPMABA precipitation during cooling or storage, which could cause testing errors, the sample is mixed with acetone after sampling before being sent for testing (m 样品 :m 丙酮 =1:1).

[0085] Testing revealed that the CPMABA content in the coalescing sample obtained from the sampling port was 2230 ppm. After 48 hours of treatment in the coalescing tank, the CPMABA content in the outlet sample decreased to 1560 ppm, with an oil removal efficiency of 30%. The CPMABA content in the upper oil collection bag was 2870 ppm, slightly higher than that in the inlet sample. These results indicate that conventional coalescing tanks have limited enrichment effects and cannot efficiently remove CPMABA oily substances from PPS brine.

[0086] After the coalescer had been running stably for a period of time, the coalescence effect began to decline. After process investigation, black blockage was found at the coalescer inlet.

[0087] Example 10

[0088] This embodiment uses an improved horizontal coalescer. A schematic diagram of the specific coalescing method is shown below. Figure 2 As shown:

[0089] The process flow diagram includes a salt solution transfer tank 1, a hydrochloric acid metering tank 2, a static mixer 3, and a horizontal coalescer 4; the various devices are connected by sealed pipes, and all devices and pipes are insulated with hot water; a sampling port 5 is provided on the pipe connecting the static mixer 3 and the horizontal coalescer 4.

[0090] The horizontal coalescer 4 includes, in sequence along the feed direction, a multi-stage filter element 41, a lower oil collection chamber 44, an upper oil collection chamber 42, and an outlet valve 43; the multi-stage filter element 41 uses a PP-PF filter element.

[0091] The production process is exactly the same as in Example 9.

[0092] Testing showed that after 48 hours of treatment in the coalescer, the CPMABA content in the outlet sample decreased to 1090 ppm, with an oil removal efficiency of 51%, indicating a significant increase in removal effectiveness. Furthermore, the CPMABA contents in the upper and lower oil collection bags (sampled by opening the drain port of the lower oil collection bag) were 2630 ppm and 4810 ppm, respectively, significantly higher than the CPMABA content in the inlet sample. In conclusion, adding the lower oil collection bag significantly improves the enrichment effect of the coalescer, enabling efficient removal of CPMABA oily substances from PPS brine.

[0093] Example 11

[0094] This embodiment uses a conventional horizontal coalescer. A schematic diagram of the specific coalescing method is shown below. Figure 3 As shown:

[0095] The process flow diagram includes a salt solution transfer tank 1, a hydrochloric acid metering tank 2, a static mixer 3, a horizontal coalescer 4, and a filter 6; the various devices are connected by sealed pipes, and all devices and pipes are insulated with hot water; a sampling port 5 is provided on the pipe connecting the static mixer 3 and the filter 6.

[0096] The horizontal coalescer 4 includes, in sequence along the feed direction, a multi-stage filter element 41, a lower oil collection chamber 44, an upper oil collection chamber 42, and an outlet valve 43; the multi-stage filter element 41 uses a PP-PF filter element.

[0097] S1. Install the horizontal coalescer, according to... Figure 3 The process flow diagram is used for on-site piping, and 80℃ hot water is used for insulation. Figure 1 Compared to the previous process flow diagram, a filter has been added;

[0098] S2~S6 are the same as in example 9.

[0099] After 48h treatment by the coalescer, the CPMABA content in the outlet sample was reduced to 760ppm, and the removal rate reached 66%, the removal effect was greatly increased. In addition, the CPMABA contents in the upper and lower oil collection bags were 2490ppm and 5030ppm respectively, which were significantly higher than the CPMABA content in the inlet sample. The coalescer could run stably, and the plugging phenomenon was obviously improved. And by visual observation, the wastewater at the outlet of the coalescer was significantly clearer than the inlet wastewater.

[0100] In summary, after adding the filter, the coalescer can stably and efficiently remove CPMABA in the salt water.

[0101] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. The above application of specific examples is used to help understand the present application, and is not used to limit the present application. The skilled in the art of the present application can make several simple deductions, deformations, substitutions or combinations according to the concept of the present application. These deductions, deformations, substitutions or combinations also fall within the scope of the claims of the present application.

Claims

1. A coalescence method for removing CPMABA from PPS brine, characterized in that, It comprises the following steps: S1, taking PPS brine containing CPMABA and adjusting its pH value to be acidic to obtain pretreated PPS brine; Heating the PPS brine containing CPMABA to 80-90℃; Adjusting the pH value to be 3-4; S2, passing the pretreated PPS brine into a coalescing device for coalescing treatment; The pretreated PPS brine is first pre-filtered and then passed into a coalescing device for coalescing treatment; The filter core material used in the coalescing device is selected from polypropylene-phenolic resin composite material; A lower oil collection bag is added at the outlet of the coalescing device.

2. The coalescence process for removing CPMABA from PPS brine according to claim 1, characterized in that, The pre-filtering uses a filter core with a pore size ≤1 μm.

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