阅读说明：本技术 聚苯硫醚生产用低聚物回收方法以及装置 (Method and device for recovering oligomer for polyphenylene sulfide production ) 是由 吕天生 胡洪铭 谢晓鸿 陈尚敬 刘源丹 陈晓秋 黄国庆 于 2020-08-20 设计创作，主要内容包括：本发明公开了一种聚苯硫醚低聚物回收方法,包括以下步骤：S1：收集滤液和洗液存储于滤液混合储槽形成混合液；S2：混合液泵入混合过滤器内过滤形成低聚物滤饼；S3：将混合过滤器底部低聚物滤饼收集到一洗搅拌罐里,加入洗水搅拌洗涤后进入一洗过滤器过滤形成一洗低聚物；S4：将一洗过滤器底部的一洗低聚物收集到二洗搅拌罐里,加入洗水搅拌洗涤后进入二洗过滤器过滤形成二洗低聚物；S5：将二洗过滤器底部的二洗低聚物收集到混料仓,经由进料器均匀加入干燥器中加热干燥得到低聚物回收产品。本发明通过过滤、洗涤、干燥得以回收滤液中的具有一定经济价值的低聚物的同时,减少了固废排放,实现节能减排的环保要求。(The invention discloses a polyphenylene sulfide oligomer recovery method, which comprises the following steps: s1: collecting filtrate and washing liquid, and storing the filtrate and the washing liquid in a filtrate mixing storage tank to form mixed liquid; s2: pumping the mixed solution into a mixing filter and filtering to form an oligomer filter cake; s3: collecting oligomer filter cakes at the bottom of the mixing filter into a washing stirring tank, adding washing water, stirring and washing, and then, filtering in a washing filter to form washing oligomer; s4: collecting the first-washing oligomer at the bottom of the first-washing filter into a second-washing stirring tank, adding washing water, stirring, washing, and then filtering in a second-washing filter to form second-washing oligomer; s5: collecting the second-washing oligomer at the bottom of the second-washing filter into a mixing bin, uniformly adding the second-washing oligomer into a dryer through a feeder, heating and drying to obtain an oligomer recovery product. According to the invention, the oligomer with a certain economic value in the filtrate is recovered through filtering, washing and drying, and meanwhile, the solid waste discharge is reduced, and the environmental protection requirements of energy conservation and emission reduction are realized.)

1. A polyphenylene sulfide oligomer recovery method is characterized by comprising the following steps:

s1: collecting filtrate and washing liquid, and storing the filtrate and the washing liquid in a filtrate mixing storage tank to form mixed liquid;

s2: pumping the mixed solution into a mixing filter and filtering to form an oligomer filter cake;

s3: collecting oligomer filter cakes at the bottom of the mixing filter into a washing stirring tank, adding washing water, stirring and washing, and then, filtering in a washing filter to form washing oligomer;

s4: collecting the first-washing oligomer at the bottom of the first-washing filter into a second-washing stirring tank, adding washing water, stirring, washing, and then filtering in a second-washing filter to form second-washing oligomer;

s5: collecting the second-washing oligomer at the bottom of the second-washing filter into a mixing bin, uniformly adding the second-washing oligomer into a dryer through a feeder, heating and drying to obtain an oligomer recovery product.

2. The polyphenylene sulfide oligomer recycling method of claim 1, wherein the mixing filter, the first washing filter and the second washing filter in steps S2-S5 are all tube filters.

3. The polyphenylene sulfide oligomer recovery method according to claim 1, wherein the volume ratio of the oligomer to the washing water in steps S3 and S4 is 1:5 to 1:15, and the stirring and washing time is 10 to 30 minutes.

4. The method for recovering polyphenylene sulfide oligomer according to claim 1, wherein in step S5, the polyphenylene sulfide oligomer is dried by steam heating at a temperature of 80 to 110 ℃ under a vacuum of-0.08 to-0.1 MPa, and the water content of the dried oligomer is 0.1 to 5%.

5. The polyphenylene sulfide oligomer recovery method of claim 2, wherein the filter comprises the steps of:

a1: the feed liquid in the raw material tank is circulated, stirred and mixed uniformly;

a2: injecting feed liquid into the filter, and overflowing and filling;

a3: continuously feeding and pre-coating circulation to form a filtering layer on the surface of the filter element of the filter;

a4: after the filtering layer is formed, adjusting the pressure in the filter and starting filtering;

a5: after the filtration is finished, stopping feeding, and introducing compressed air to press out the residual materials in the filter;

a6: after pressing out the residual materials, introducing compressed air into the filter, and pre-drying the filter cake;

a7: after the pre-drying is finished, the slag is discharged by alternately switching vacuum and compressed air in the filter;

a8: and opening the backwashing water, introducing compressed air and cleaning the filter.

6. The method for recovering oligomers for polyphenylene sulfide production according to claim 6, wherein a time for the liquid injection in step A2 is 15 to 25 minutes.

7. The method for recovering oligomers for polyphenylene sulfide production according to claim 6, wherein the precoating time in the step A3 is 15 to 120 minutes.

8. The method for recovering oligomers for polyphenylene sulfide production according to claim 6, wherein in the step A4, the filtration time is 20 to 240 minutes, the filtration pressure is 0.3 to 0.5MPa, and the temperature of the liquid is controlled to 40 to 60 ℃.

Technical Field

The invention relates to the technical field of chemical production, in particular to a method for recovering oligomers for polyphenylene sulfide production.

Background

Polyphenylene Sulfide (PPS), abbreviated as English, is a novel high-performance thermoplastic resin, has excellent heat resistance, chemical resistance, flame retardance, mechanical property and electrical property, can be blended and modified, and is widely applied to automobiles, machinery, chemical engineering, electronics, aerospace and the like at present.

At present, the sodium sulfide pressure polycondensation method is the most mature industrialized production method of polyphenylene sulfide, a certain amount of oligomers can be generated in the synthesis process of the polyphenylene sulfide, and the oligomers are mixed in the synthetic slurry filtrate and the washing and purifying liquid of a PPS product, so that the recovery of other components in the filtrate and the washing liquid can be seriously influenced, the process equipment is blocked, solid wastes can be formed, and the environmental protection treatment pressure is increased.

The PPS oligomer is a low-molecular-weight polymer with less repeating units formed by connecting benzene rings and sulfur, has lower melting point and crystallinity and better solubility in a polar organic solvent, can be used as a copolymerization modification raw material, can also be used as a charge transfer agent of a photoelectric semiconductor, a plastic additive and the like, and has higher economic value.

In view of the above, the recycling of polyphenylene sulfide oligomers is necessary both from the environmental point of view and from the cost control point of view, but there is no method available at present which is easy to handle, low in cost and efficient.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, the present application provides a method for recovering polyphenylene sulfide oligomers with convenient operation, low cost and high efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme:

a polyphenylene sulfide oligomer recovery method is characterized by comprising the following steps:

s1: collecting filtrate and washing liquid, and storing the filtrate and the washing liquid in a filtrate mixing storage tank to form mixed liquid;

s2: pumping the mixed solution into a mixing filter and filtering to form an oligomer filter cake;

s3: collecting oligomer filter cakes at the bottom of the mixing filter into a washing stirring tank, adding washing water, stirring and washing, and then, filtering in a washing filter to form washing oligomer;

s4: collecting the first-washing oligomer at the bottom of the first-washing filter into a second-washing stirring tank, adding washing water, stirring, washing, and then filtering in a second-washing filter to form second-washing oligomer;

s5: collecting the second-washing oligomer at the bottom of the second-washing filter into a mixing bin, uniformly adding the second-washing oligomer into a dryer through a feeder, heating and drying to obtain an oligomer recovery product.

Specifically, the mixing filter, the first washing filter and the second washing filter in the steps S2 to S5 are all tube filters.

Specifically, the volume ratio of the oligomer to the washing water in the steps S3 and S4 is 1: 5-1: 15, and the stirring and washing time is 10-30 minutes.

Specifically, in the step S5, steam is used for heating and drying, the drying temperature is 80-110 ℃, the vacuum degree is-0.08-0.1 MPa, and the water content of the dried oligomer is 0.1-5.0%.

Further, the working steps of the filter are as follows:

a1: the feed liquid in the raw material tank is circulated, stirred and mixed uniformly;

a2: injecting feed liquid into the filter, and overflowing and filling;

a3: continuously feeding and pre-coating circulation to form a filtering layer on the surface of the filter element of the filter;

a4: after the filtering layer is formed, adjusting the pressure in the filter and starting filtering;

a5: after the filtration is finished, stopping feeding, and introducing compressed air to press out the residual materials in the filter;

a6: after pressing out the residual materials, introducing compressed air into the filter, and pre-drying the filter cake;

a7: after the pre-drying is finished, the slag is discharged in the filter element by alternately switching vacuum and compressed air;

a8: and opening the backwashing water, introducing compressed air and cleaning the filter.

Specifically, the liquid injection time in the step A2 is 15-25 minutes.

Specifically, the pre-coating time in the step A3 is 15-120 minutes.

Specifically, in the step A4, the filtering time is 20-240 minutes, the filtering pressure is 0.3-0.5 MPa, and the temperature of the feed liquid is controlled at 40-60 ℃.

The method can realize the recovery of oligomers in the filtrate and the washing liquid, and the oligomers collected by filtering and separating are washed and dried for multiple times to obtain solid recovered oligomers, and the recovered oligomers have certain economic value, can reduce the cost of the production process, reduce the emission, meet the environmental protection requirements of energy conservation and emission reduction, and simultaneously avoid the influence of the oligomers on the subsequent separation process.

Drawings

FIG. 1 is a flow chart showing the method for recovering oligomers for polyphenylene sulfide production according to the present invention.

FIG. 2 is a schematic diagram showing an example of the method for recovering an oligomer for polyphenylene sulfide production according to the present invention.

FIG. 3 is a schematic view of an embodiment of the filter according to the present invention.

Description of reference numerals:

1-filtrate mixing storage tank, 2-mixed liquid pump, 3-mixed liquid tubular filter, 4-coarse filtrate storage tank, 5-first washing stirring tank, 6-first washing material pump, 7-first washing tubular filter, 8-second washing stirring tank, 9-second washing material pump, 10-second washing tubular filter, 11-mixing bin, 12-feeder, 13-drier, 14-conveyor, 15-finished product bin, 16 compressed air pipe, 17-washing water pipe and 18-vacuum pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.