阅读说明：本技术 一种用于顺酐溶剂净化再利用的装置及工艺 (Device and process for purifying and recycling maleic anhydride solvent ) 是由 孙玉玉 郭凯 黄益平 李玉光 黄晶晶 张锴 乔凯 岳昌海 于 2021-07-26 设计创作，主要内容包括：本发明提供一种用于顺酐溶剂净化再利用的装置,包括贫溶剂储罐、预热器、脉动泵、微混合器、油水分离器和分子筛透水膜组件。本发明还公开了一种用于顺酐溶剂净化再利用的工艺。本发明将含杂质的贫溶剂经预热后与水泵入微混合器,使贫溶剂中的杂质在水中充分溶解,实现与油相的分离,再经油水分离器进行分相,含少量水的溶剂经分子筛透水膜组件脱水后达到净化效果。该工艺可高效实现有机物中少量杂质的分离,溶剂回收率达99.4%以上,分离能耗低,分离效果显著,有利于在顺酐溶剂回收领域中推广应用。(The invention provides a device for purifying and recycling a maleic anhydride solvent, which comprises a poor solvent storage tank, a preheater, a pulse pump, a micro mixer, an oil-water separator and a molecular sieve permeable membrane component. The invention also discloses a process for purifying and recycling the maleic anhydride solvent. The invention preheats the poor solvent containing impurities and pumps the poor solvent and water into a micro mixer to fully dissolve the impurities in the poor solvent in the water to realize the separation with an oil phase, then carries out phase splitting through an oil-water separator, and the solvent containing a small amount of water achieves the purification effect after being dehydrated through a molecular sieve permeable membrane component. The process can efficiently realize the separation of a small amount of impurities in organic matters, the solvent recovery rate reaches more than 99.4 percent, the separation energy consumption is low, the separation effect is obvious, and the process is favorable for popularization and application in the field of maleic anhydride solvent recovery.)

1. An apparatus for purifying and reusing maleic anhydride solvent, comprising: the device comprises a lean solvent storage tank, a preheater, a pulse pump, a micro mixer, an oil-water separator and a molecular sieve permeable membrane component;

wherein the outlet end of the lean solvent storage tank is connected with the inlet end of the preheater; the outlet end of the preheater is connected with the inlet end of the pulse pump; the outlet end of the pulsation pump is connected with the first inlet end of the micro mixer; the second inlet end of the micro mixer is connected with a deionized water pipeline; the outlet end of the micro mixer is connected with the inlet end of the oil-water separator;

the oil phase discharge end of the oil-water separator is connected with the inlet end of the molecular sieve permeable membrane component; the water phase discharge end of the oil-water separator is connected with a wastewater treatment system;

the oil phase discharge end of the molecular sieve permeable membrane component is connected with a qualified circulating solvent treatment system; and the water phase discharge end of the molecular sieve permeable membrane component is connected with a wastewater treatment system.

2. The apparatus of claim 1, wherein the micro-mixer has a cross-section that is at least one of rectangular, circular, square, trapezoidal, elliptical, triangular, and rounded rectangular.

3. A process for purifying and recycling a maleic anhydride solvent is characterized by comprising the following steps:

s1, preheating the lean solvent containing impurities in a lean solvent storage tank in a preheater, pumping the preheated lean solvent and deionized water into a micro mixer through a pulse pump, fully contacting the impurities in the lean solvent and the deionized water in the micro mixer, and mixing and dissolving to obtain an oil-water mixture;

s2, extracting the oil-water mixture from the outlet end of the micro mixer, allowing the oil-water mixture to enter the inlet end of an oil-water separator, standing and layering the oil-water mixture in the oil-water separator to obtain an upper oil phase and a lower wastewater phase, and allowing the lower wastewater phase to enter a wastewater treatment system;

and S3, allowing the upper oil phase to enter a molecular sieve permeable membrane component, adsorbing by a molecular sieve, extracting a qualified circulating solvent from the oil phase discharge end of the molecular sieve permeable membrane component for maleic anhydride absorption, and extracting deoiled wastewater from the water phase discharge end to enter a wastewater treatment system.

4. The process according to claim 3, wherein the lean solvent is at least one of dipropyl phthalate, diisopropyl phthalate, dibutyl phthalate, diisobutyl hexahydrophthalate, diethyl tetrahydrophthalate.

5. The process of claim 3 wherein the impurities in the lean solvent are at least one of acrylic acid, maleic acid, fumaric acid, phthalic acid, maleic anhydride, tar.

6. The process of claim 3 wherein the lean solvent to deionized water feed mass ratio is 10: 1-3: 1.

7. the process of claim 3, wherein the preheater is operated at a temperature of from 40 ℃ to 70 ℃.

8. The process of claim 3 wherein the flow rate at the discharge end of the micromixer is from 15 to 30mL/min and the mixing time of the lean solvent and deionized water in the micromixer is from 3 to 8 min.

9. The process of claim 3 wherein the water content of the upper oil phase is from 2 to 10%.

10. The process of claim 3, wherein the support of the water permeable membrane module is a NaA molecular sieve, a hollow fiber alumina or a silica alumina molecular sieve.

Technical Field

The invention belongs to the technical field of maleic anhydride production, and particularly relates to a device and a process for purifying and recycling a maleic anhydride solvent.

Background

Maleic anhydride is a common important organic chemical raw material, and the consumption of the maleic anhydride is second to that of phthalic anhydride and acetic anhydride. The method is mainly used for producing unsaturated polyester resin, BDO, paint and the like, the demand of maleic anhydride is vigorous in recent years, the market prospect is good, the price of downstream BDO is continuously increased, and the import quantity is kept at a high scale.

The existing maleic anhydride production process can be generally divided into two parts, namely an oxidation process and a post-treatment process, wherein the oxidation process can be divided into a benzene method and a normal butane method according to raw materials, and the post-treatment process mainly comprises a water absorption method and a solvent absorption method. In recent years, the normal butane method device shows a rapid development trend due to the advantages of low price of the raw material normal butane, high product yield, stable product quality, low energy consumption, high profit and the like.

The maleic anhydride recovery from the maleic anhydride reaction gas mainly comprises two processes of water absorption and solvent absorption, and in the water absorption process, fumaric acid impurities are easily generated due to improper temperature control during absorption and dehydration operation, so that a tower tray is blocked, and the energy consumption of dehydration operation of the device is increased. The absorption process of the solvent absorption process does not have the process of hydration of maleic anhydride into maleic acid, the possibility of blockage of the device is greatly reduced, the recovery rate of the maleic anhydride post-treatment process is effectively improved, the operation stability of the device is also improved, the production time is increased, and the economic benefit is improved.

However, in the production process of maleic anhydride by the n-butane method, due to the existence of n-butane, the selectivity of the maleic anhydride is low, acetic acid, acrylic acid and the like are mainly produced as byproducts, and meanwhile, due to the fact that a solvent contains a small amount of water in the solvent absorption process, maleic acid and fumaric acid are produced when the maleic anhydride meets water, the acid produced in the process can be dissolved in the solvent for absorbing the maleic anhydride, and the maleic anhydride is still difficult to completely remove in the subsequent desorption process of the maleic anhydride. Meanwhile, the consumption of the solvent for absorbing the maleic anhydride is large, and the effect of removing the maleic anhydride by the desorption process is good, so that the solvent can be recycled. If the impurity acid dissolved in the solvent is not treated, the acid is continuously accumulated in the solvent, thereby affecting the absorption effect of the solvent and the yield of the maleic anhydride.

At present, the poor solvent which is recycled is industrially treated by adopting a centrifugal extraction technology, the poor solvent containing impurities and water are premixed and then enter a centrifugal extractor, but because the density of the poor solvent containing impurities and the density of water are close, the density difference is only 0.045kg/m3, the separation of the solvent and the water is difficult to realize by the domestic centrifugal extractor, and meanwhile, the content of the solvent in the treated wastewater phase is high, the water content of an organic phase also reaches about 3 percent, although the imported centrifugal extractor can realize the oil-water separation to a certain extent, the equipment price is high, and the development of a novel device for purifying and recycling the maleic anhydride solvent to replace the centrifugal extractor is a difficult problem in the maleic anhydride production field at present.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides a device and a process for purifying and recycling a maleic anhydride solvent, which can effectively realize the separation of a small amount of impurities in organic matters, and have the advantages of low separation energy consumption, high solvent recovery rate, low water content in the solvent, low device equipment investment and stable operation effect.

The invention provides a device for purifying and recycling a maleic anhydride solvent, which comprises: the device comprises a lean solvent storage tank, a preheater, a pulse pump, a micro mixer, an oil-water separator and a molecular sieve permeable membrane component;

wherein the outlet end of the lean solvent storage tank is connected with the inlet end of the preheater; the outlet end of the preheater is connected with the inlet end of the pulse pump; the outlet end of the pulsation pump is connected with the first inlet end of the micro mixer; the second inlet end of the micro mixer is connected with a deionized water pipeline; the outlet end of the micro mixer is connected with the inlet end of the oil-water separator;

the oil phase discharge end of the oil-water separator is connected with the inlet end of the molecular sieve permeable membrane component; the water phase discharge end of the oil-water separator is connected with a wastewater treatment system;

the oil phase discharge end of the molecular sieve permeable membrane component is connected with a qualified circulating solvent treatment system; and the water phase discharge end of the molecular sieve permeable membrane component is connected with a wastewater treatment system.

Preferably, the cross section of the micro mixer is at least one of rectangular, circular, square, trapezoidal, oval, triangular and rounded rectangle.

The invention also provides a process for purifying and recycling the maleic anhydride solvent, which comprises the following steps:

s1, preheating the lean solvent containing impurities in a lean solvent storage tank in a preheater, pumping the preheated lean solvent and deionized water into a micro mixer through a pulse pump, fully contacting the impurities in the lean solvent and the deionized water in the micro mixer, and mixing and dissolving to obtain an oil-water mixture;

s2, extracting the oil-water mixture from the outlet end of the micro mixer, allowing the oil-water mixture to enter the inlet end of an oil-water separator, standing and layering the oil-water mixture in the oil-water separator to obtain an upper oil phase and a lower wastewater phase, and allowing the lower wastewater phase to enter a wastewater treatment system;

and S3, allowing the upper oil phase to enter a molecular sieve permeable membrane component, adsorbing by a molecular sieve, extracting a qualified circulating solvent from the oil phase discharge end of the molecular sieve permeable membrane component for maleic anhydride absorption, and extracting deoiled wastewater from the water phase discharge end to enter a wastewater treatment system.

Preferably, the lean solvent is at least one of dipropyl phthalate, diisopropyl phthalate, dibutyl phthalate, diisobutyl hexahydrophthalate and diethyl tetrahydrophthalate.

Preferably, the impurities in the lean solvent are at least one of acrylic acid, maleic acid, fumaric acid, phthalic acid, maleic anhydride and tar.

Preferably, the feed mass ratio of lean solvent to deionized water is 10: 1-3: 1.

preferably, the operating temperature of the preheater is in the range of 40 to 70 ℃.

Preferably, the flow rate at the discharge end of the micro mixer is 15-30mL/min, and the mixing time of the lean solvent and the deionized water in the micro mixer is 3-8 min.

Preferably, the water content in the upper oil phase is 2-10%.

Preferably, the carrier of the molecular sieve permeable membrane component is a NaA molecular sieve, a hollow fiber alumina or a silicon-aluminum molecular sieve.

Compared with the prior art, the invention has the beneficial effects that:

1. the method adopts the micro-mixer coupled with the molecular sieve permeable membrane component to realize the removal of acid impurities and water in the maleic anhydride solvent, and the purification effect of the maleic anhydride solvent is obvious.

2. The pre-heater is arranged before the maleic anhydride poor solvent enters the micro mixer, the flow of the pulse pump is adjusted, the feeding temperature and the feeding flow rate of the poor solvent entering the micro mixer are controlled, the organic acid in the poor solvent is ensured to be fully contacted with deionized water in the micro mixer and dissolved in the deionized water, the effective removal of the organic acid in the maleic anhydride poor solvent is realized, and the removal rate of acrylic acid and fumaric acid reaches 100 percent.

3. Aiming at the problems that the density of the poor solvent is close to that of water and phase separation is possibly incomplete, the molecular sieve permeable membrane component is arranged, and the oil phase after phase separation is dehydrated through the molecular sieve permeable membrane component, so that the water content in the circulating absorbent is effectively reduced, and the generation of maleic anhydride and fumaric acid is reduced, thereby reducing the content of the maleic anhydride and the fumaric acid in the poor solvent from the source and ensuring the purification effect of the solvent.

4. The device and the process for purifying and recycling the maleic anhydride solvent have the advantages of low separation energy consumption, high solvent recovery rate of over 99.4 percent, low device equipment investment and stable operation effect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Wherein, 1, a lean solvent storage tank; 2. a preheater; 3. a pulsating pump; 4. a micro mixer; 5. an oil-water separator; 6. a molecular sieve permeable membrane component.

a. A lean solvent comprising impurities; b. deionized water; c. an oil-water mixture; d. an upper oil phase; e. a lower wastewater phase; f. qualified recycle lean solvent; g. waste water after deoiling.

Detailed Description

The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.

Example 1

Referring to fig. 1, an apparatus for purifying and reusing a maleic anhydride solvent, comprising: a poor solvent storage tank 1, a preheater 2, a pulse pump 3, a micro mixer 4, an oil-water separator 5 and a molecular sieve water permeable membrane component 6.

Wherein the outlet end of the lean solvent storage tank 1 is connected with the inlet end of the preheater 2; the outlet end of the preheater 2 is connected with the inlet end of the pulsation pump 3; the outlet end of the pulsation pump 3 is connected with the first inlet end of the micro mixer 4; the second inlet end of the micro mixer 4 is connected with a deionized water pipeline; the outlet end of the micro mixer 4 is connected with the inlet end of the oil-water separator 5.

The oil phase discharge end of the oil-water separator 5 is connected with the inlet end of the molecular sieve permeable membrane component 6; the water phase discharge end of the oil-water separator 5 is connected with a wastewater treatment system.

The oil phase discharge end of the molecular sieve permeable membrane component 6 is connected with a qualified circulating solvent treatment system; the water phase discharge end of the molecular sieve permeable membrane component 6 is connected with a wastewater treatment system.

Example 2

A process for purification and reuse of maleic anhydride solvent using the apparatus of example 1, said process comprising the steps of:

s1, cooling the lean solvent extracted by the flash tower after the absorption section of the maleic anhydride solvent, then feeding the cooled lean solvent into a lean solvent storage tank 1, extracting the impurity-containing lean solvent a from the outlet end of the lean solvent storage tank 1, preheating the solvent to 40 ℃ by a preheater 2, pumping the impurity-containing lean solvent a into a micro mixer 4 with a rectangular cross section at a flow rate of 22.33 mL/min by a pulsating pump 3, pumping the deionized water b with a temperature of 40 ℃ into the micro mixer 4 at a flow rate of 4.63 mL/min, aerating and dispersing the impurity-containing lean solvent and the deionized water near the inlet end of the micro mixer 4, then feeding the impurity-containing lean solvent and the deionized water into an internal channel of the micro mixer 4, and fully contacting the impurities in the lean solvent with water in the channel of the micro mixer 4 and dissolving the impurities in the water to obtain an oil-water mixture c;

s2, extracting the oil-water mixture c from the outlet end of the micro mixer 4 at a flow rate of 27.67 mL/min, allowing the oil-water mixture c to enter the inlet end of the oil-water separator 5, standing the oil-water separator 5 for 5min for layering, extracting an upper oil phase d at a flow rate of 22.58 mL/min, and extracting a lower wastewater phase e at a flow rate of 4.48 mL/min to enter a wastewater treatment system;

s3, the water content of the upper oil phase is 6.104%, the upper oil phase enters the molecular sieve water permeable membrane component 6, a small amount of water contained in the oil phase is adsorbed by the molecular sieve through NaA molecular sieve adsorption, a qualified circulating poor solvent f is extracted from the oil phase discharging end of the molecular sieve water permeable membrane component 6 and is used for maleic anhydride absorption, and the deoiled wastewater g is extracted from the water phase discharging end and enters a wastewater treatment system.

Wherein, the content (mass fraction, the same below) of dibutyl phthalate in the lean solvent extracted from the outlet end of the lean solvent storage tank 1 is 97.84%, the content of acrylic acid is 0.002%, the content of maleic anhydride is 0.112%, the content of maleic acid is 0.212%, the content of fumaric acid is 0.062%, the content of phthalic anhydride is 0.176%, the content of phthalic acid is 0.020%, the content of tar is 1.45%, and the content of water is 0.13%.

The content of dibutyl phthalate in the organic phase extracted from the oil phase discharge end of the oil-water separator 5 was 92.356%, the content of acrylic acid was 0.00%, the content of maleic anhydride was 0.007%, the content of maleic acid was 0.067%, the content of fumaric acid was 0.00%, the content of phthalic anhydride was 0.088%, the content of phthalic acid was 0.018%, the content of tar was 1.36%, and the content of water was 6.104%.

The content of dibutyl phthalate in the wastewater phase extracted from the water phase discharge end of the oil-water separator 5 was 3.51%, the content of acrylic acid was 0.0139%, the content of maleic anhydride was 0.731%, the content of maleic acid was 0.987%, the content of fumaric acid was 0.433%, the content of phthalic anhydride was 0.582%, the content of phthalic acid was 0.007%, the content of tar was 0.117%, and the content of water was 93.61%.

The content of dibutyl phthalate in the qualified poor solvent extracted from the oil phase discharge end of the molecular sieve water permeable membrane component 6 is 98.36%, the content of acrylic acid is 0.00%, the content of maleic anhydride is 0.007%, the content of maleic acid is 0.071%, the content of fumaric acid is 0.00%, the content of phthalic anhydride is 0.094%, the content of phthalic acid is 0.019%, and the content of tar is 1.45%.

In conclusion, through the purification of the device and the process for purifying and recycling the maleic anhydride solvent, the recovery rate of dibutyl phthalate is 99.48%, the removal rate of acrylic acid in the maleic anhydride solvent reaches 100%, the removal rate of maleic anhydride reaches 94.41%, the removal rate of maleic acid reaches 66.69%, the removal rate of fumaric acid reaches 100%, the removal rate of phthalic anhydride reaches 47.31%, the removal rate of phthalic acid reaches 5.15%, and the removal rate of tar reaches 11.53%.

Example 3

A process for purification and reuse of maleic anhydride solvent using the apparatus of example 1, said process comprising the steps of:

s1, cooling the lean solvent extracted by the flash tower after the absorption section of the maleic anhydride solvent, then feeding the cooled lean solvent into a lean solvent storage tank 1, extracting the lean solvent a containing impurities from the outlet end of the lean solvent storage tank 1, preheating the lean solvent a to 70 ℃ by a preheater 2, pumping the lean solvent a containing impurities into a micro mixer 4 with a circular cross section by a pulse pump 3 at a flow rate of 18.61 mL/min, pumping the deionized water b at 70 ℃ into the micro mixer 4 at a flow rate of 5.02 mL/min, aerating and dispersing the lean solvent containing impurities and the deionized water near the inlet end of the micro mixer 4, then feeding the impurities into a channel inside the micro mixer 4, and fully contacting the impurities in the lean solvent with water in the channel of the micro mixer 4 and dissolving the impurities in the water to obtain an oil-water mixture c;

s2, extracting the oil-water mixture c from the outlet end of the micro mixer 4 at a flow rate of 24.43 mL/min, allowing the oil-water mixture c to enter the inlet end of the oil-water separator 5, standing the oil-water separator 5 for 4 min for layering, extracting an upper oil phase d at a flow rate of 18.82 mL/min, and extracting a lower waste water phase e at a flow rate of 4.85 mL/min to enter a waste water treatment system;

s3, the water content of the upper oil phase is 3.628%, the upper oil phase enters the molecular sieve water permeable membrane component 6, a small amount of water contained in the oil phase is adsorbed by the molecular sieve through the silicon-aluminum molecular sieve, a qualified circulating poor solvent f is extracted from the oil phase discharging end of the molecular sieve water permeable membrane component 6 and is used for maleic anhydride absorption, and the deoiled wastewater g is extracted from the water phase discharging end and enters a wastewater treatment system.

Wherein, the content (mass fraction, the same below) of dibutyl phthalate in the lean solvent extracted from the outlet end of the lean solvent storage tank 1 is 65.37%, the content of diisobutyl hexahydrophthalate is 32.62%, the content of acrylic acid is 0.001%, the content of maleic anhydride is 0.105%, the content of maleic acid is 0.067%, the content of fumaric acid is 0.107%, the content of phthalic anhydride is 0.117%, the content of phthalic acid is 0.017%, the content of hexahydrophthalic acid is 0.066%, and the content of tar is 1.53%.

The content of dibutyl phthalate in the organic phase extracted from the oil phase discharge end of the oil-water separator 5 was 63.27%, the content of diisobutyl hexahydrophthalate was 31.57%, the content of acrylic acid was 0.00%, the content of maleic anhydride was 0.004%, the content of maleic acid was 0.023%, the content of fumaric acid was 0.00%, the content of phthalic anhydride was 0.074%, the content of phthalic acid was 0.009%, the content of hexahydrophthalic acid was 0.012%, the content of tar was 1.32%, and the content of water was 3.718%.

The content of dibutyl phthalate in the wastewater phase extracted from the water phase discharge end of the oil-water separator 5 was 0.00%, the content of diisobutyl hexahydrophthalate was 0.01%, the content of acrylic acid was 0.004%, the content of maleic anhydride was 0.452%, the content of maleic acid was 0.194%, the content of fumaric acid was 0.480%, the content of phthalic anhydride was 0.182%, the content of phthalic acid was 0.035%, the content of hexahydrophthalic acid was 0.240%, the content of tar was 0.745%, and the content of water was 97.66%.

The content of dibutyl phthalate in qualified lean solvent extracted from the oil phase discharge end of the molecular sieve water permeable membrane component 6 is 65.64%, the content of diisobutyl hexahydrophthalate is 32.76%, the content of acrylic acid is 0.00%, the content of maleic anhydride is 0.004%, the content of maleic acid is 0.024%, the content of fumaric acid is 0.00%, the content of phthalic anhydride is 0.077%, the content of phthalic acid is 0.009%, the content of hexahydrophthalic acid is 0.012%, and the content of tar is 1.37%.

In conclusion, through the purification of the device and the process for purifying and recycling the maleic anhydride solvent, the recovery rate of dibutyl phthalate is more than or equal to 99.99%, the recovery rate of diisobutyl hexahydrophthalate is 99.99%, the removal rate of acrylic acid in the maleic anhydride solvent reaches 100%, the removal rate of maleic anhydride reaches 96.06%, the removal rate of maleic acid reaches 64.53%, the removal rate of fumaric acid reaches 100%, the removal rate of phthalic anhydride reaches 34.65%, the removal rate of phthalic acid reaches 45.30%, the removal rate of hexahydrophthalic acid reaches 81.21%, and the removal rate of tar reaches 10.86%.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures made by using the contents of the present specification and the drawings can be directly or indirectly applied to other related technical fields, and are within the scope of the present invention.