阅读说明：本技术 D-d混剂精馏分离工艺 (D-D mixture rectification separation process ) 是由 薄纯金 宋朋斌 张延军 王国力 于 2020-07-23 设计创作，主要内容包括：本发明提供了一种D-D混剂精馏分离工艺,包括以下步骤：工艺母液D-D混剂中的易碳化重组分与其轻组分在脱重塔内传质分离；二氯丙烯及轻组分蒸发气相经塔顶分凝器控制回流,不凝气相直接送入脱轻塔；二氯丙烷及轻组分与二氯丙烯在脱轻塔内传质分离；二氯丙烷及轻组分蒸发气相到达脱轻塔的塔顶被冷却,脱轻塔的塔底物料送入成品塔；将脱轻塔的的塔底物料送入成品塔,顺、反式1,3二氯丙烯在成品塔内传质分离,顺式1,3二氯丙烯蒸发气相到达成品塔的塔顶被冷却进入顺式罐；从成品塔下部侧线采出反式1,3二氯丙烯。通过本发明的技术方案,采用三塔连续、变压操作以及侧线采出,产品纯度高,更加节能,顺式和反式1,3二氯丙烯产品纯度均可达到95％以上。(The invention provides a rectification separation process of a D-D mixture, which comprises the following steps: the easily carbonized heavy component and the light component in the mother liquor D-D mixture are separated in a de-heavy tower by mass transfer; the dichloropropene and the light component evaporation gas phase are controlled to flow back through a partial condenser at the top of the tower, and the non-condensable gas phase is directly sent into a light component removal tower; dichloropropane and light components are subjected to mass transfer separation with dichloroallyl in a light component removal tower; the dichloropropane and the light component evaporation gas phase reach the top of the light component removal tower to be cooled, and the material at the bottom of the light component removal tower is sent into a finished product tower; feeding the tower bottom material of the light component removal tower into a finished product tower, carrying out mass transfer separation on cis-form 1,3 dichloropropene and trans-form 1,3 dichloropropene in the finished product tower, and cooling the cis-form 1,3 dichloropropene evaporated gas phase to the top of the finished product tower to enter a cis-form tank; the trans-1, 3 dichloropropene is extracted from the lower side line of the finished product tower. By adopting the technical scheme of the invention, three-tower continuous operation, variable-pressure operation and side-draw are adopted, the product purity is high, more energy is saved, and the purity of cis-form and trans-form 1,3 dichloropropene products can reach more than 95%.)

1. A D-D mixture rectification separation process is characterized by comprising the following steps:

under the condition of reduced pressure operation, feeding a process mother liquor D-D mixed agent obtained from the bottom of a chloropropene refining process tower into a de-weighting tower, heating by steam in a tower bottom reboiler, and carrying out mass transfer separation on easily-carbonized heavy components and light components in the process mother liquor D-D mixed agent in the de-weighting tower;

the dichloropropene and light component evaporation gas phase are controlled to flow back through a top fractional condenser, the non-condensable gas phase is directly sent into a light component removal tower, and the heavy component at the bottom of the heavy component removal tower is sent into a post-working section for treatment;

under the condition of reduced pressure operation, feeding the top non-condensable gas phase of the heavy component removal tower into the light component removal tower, heating by steam through a tower bottom reboiler of the light component removal tower, and carrying out mass transfer separation on dichloropropane and light components and dichloropropylene in the light component removal tower;

the dichloropropane and the light component evaporated gas phase reach the top of the lightness-removing tower and are cooled by a condenser, the condensate enters a reflux tank, part of the condensate is sent to the tower for reflux, part of the condensate is sent to a warehouse for storage after being cooled, and the material at the bottom of the lightness-removing tower is sent to a finished product tower;

under the vacuum operation condition, feeding the tower bottom material of the light component removal tower into a finished product tower, heating by steam in a tower bottom reboiler of the finished product tower, carrying out mass transfer separation on cis-form 1,3 dichloropropene in the finished product tower, cooling a cis-form 1,3 dichloropropene evaporation gas phase reaching the tower top of the finished product tower by a condenser, feeding a condensate into a cis-form tank, feeding part of the condensate into the tower for reflux, continuously distilling part of the condensate out of the tower top, cooling, and feeding the cooled condensate into the cis-form finished product tank for storage;

and (3) extracting trans-1, 3 dichloropropene from the side line at the lower part of the finished product tower, cooling, sending into a trans-tank, sending into a trans-finished product tank for storage, and intermittently discharging heavy component residual liquid at the bottom of the finished product tower to a residual liquid tank.

2. The rectification separation process of D-D mixture according to claim 1,

the tower bottom temperature of the de-heavy tower is 108 ℃, the tower top temperature is 70.5 ℃, the tower bottom pressure is 45KPa, and the tower top pressure is 35 KPa.

3. The rectification separation process of D-D mixture according to claim 1,

the temperature of the bottom of the light component removal tower is 81 ℃, the temperature of the top of the light component removal tower is 59.1 ℃, the pressure of the bottom of the light component removal tower is 44KPa, and the pressure of the top of the light component removal tower is 32 KPa.

4. The rectification separation process of D-D mixture according to claim 1,

the temperature of the bottom of the finished product tower is 80 ℃, the temperature of the top of the finished product tower is 64 ℃, the pressure of the bottom of the finished product tower is 37KPa, and the pressure of the top of the finished product tower is 25 KPa.

5. The rectification separation process of D-D mixture according to claim 1,

and the process mother liquor D-D mixture is heated by using the waste heat of the system through a preheater and then is sent into the de-weighting tower.

6. The rectification separation process of D-D mixture according to claim 1,

reboiler at tower bottoms of the heavy component removing tower, the light component removing tower and the finished product tower are heated by steam PID automatic temperature control, and heating medium is saturated steam with pressure of 0.7 MPa.

7. The rectification separation process of D-D mixture according to claim 1,

the top of the light component removal tower and the top of the finished product tower are provided with two condensers, the cooling medium is softened water at 30 ℃, and the water supply pressure is 0.4-0.6 MPa.

Technical Field

The invention relates to the technical field of chemical rectification separation processes, and particularly relates to a D-D mixture rectification separation process.

Background

In the chloropropene production process, propylene and chlorine are generally used for producing chloropropene, the main product in the chloropropene production process is chloropropene, and byproducts D-D mixed agent and hydrochloric acid are also produced, the D-D mixed agent is directly sold as a byproduct, the product price is low, the utilization rate is low, and therefore how to carry out rectification separation on the D-D mixed agent to obtain a usable product with high value and purity becomes a technical problem to be solved urgently.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art or the related art.

Therefore, the invention aims to provide a D-D mixture rectification separation process, which can separate a byproduct D-D mixture obtained from the bottom of a chloropropene refining process so as to mix and recover 1, 2-dichloropropane and light components, wherein the product purity of cis-1, 3-dichloropropene, trans-1, 3-dichloropropene, cis-1, 3-dichloropropene and trans-1, 3-dichloropropene can reach more than 95%, and the content of cis-1, 3-dichloropropene in the trans-1, 3-dichloropropene product is not more than 0.5%.

In order to achieve the purpose, the technical scheme of the invention provides a rectification separation process of a D-D mixture, which comprises the following steps:

under the condition of reduced pressure operation, feeding a process mother liquor D-D mixed agent obtained from the bottom of a chloropropene refining process tower into a de-weighting tower, heating by steam in a tower bottom reboiler, and carrying out mass transfer separation on easily-carbonized heavy components and light components in the process mother liquor D-D mixed agent in the de-weighting tower;

the dichloropropene and light component evaporation gas phase are controlled to flow back through a top fractional condenser, the non-condensable gas phase is directly sent into a light component removal tower, and the heavy component at the bottom of the heavy component removal tower is sent into a post-working section for treatment;

under the condition of reduced pressure operation, feeding the top non-condensable gas phase of the heavy component removal tower into the light component removal tower, heating by steam through a tower bottom reboiler of the light component removal tower, and carrying out mass transfer separation on dichloropropane and light components and dichloropropylene in the light component removal tower;

the dichloropropane and the light component evaporated gas phase reach the top of the lightness-removing tower and are cooled by a condenser, the condensate enters a reflux tank, part of the condensate is sent to the tower for reflux, part of the condensate is sent to a warehouse for storage after being cooled, and the material at the bottom of the lightness-removing tower is sent to a finished product tower;

under the vacuum operation condition, feeding the tower bottom material of the light component removal tower into a finished product tower, heating by steam in a tower bottom reboiler of the finished product tower, carrying out mass transfer separation on cis-form 1,3 dichloropropene in the finished product tower, cooling a cis-form 1,3 dichloropropene evaporation gas phase reaching the tower top of the finished product tower by a condenser, feeding a condensate into a cis-form tank, feeding part of the condensate into the tower for reflux, continuously distilling part of the condensate out of the tower top, cooling, and feeding the cooled condensate into the cis-form finished product tank for storage;

and (3) extracting trans-1, 3 dichloropropene from the side line at the lower part of the finished product tower, cooling, sending into a trans-tank, sending into a trans-finished product tank for storage, and intermittently discharging heavy component residual liquid at the bottom of the finished product tower to a residual liquid tank.

Preferably, the bottom temperature of the de-heavy tower is 108 ℃, the top temperature is 70.5 ℃, the bottom pressure is 45KPa, and the top pressure is 35 KPa.

Preferably, the bottom temperature of the lightness-removing column is 81 ℃, the top temperature of the lightness-removing column is 59.1 ℃, the bottom pressure of the lightness-removing column is 44KPa, and the top pressure of the lightness-removing column is 32 KPa.

Preferably, the bottom temperature of the finished product tower is 80 ℃, the top temperature of the finished product tower is 64 ℃, the bottom pressure of the finished product tower is 37KPa, and the top pressure of the finished product tower is 25 KPa.

Preferably, the process mother liquor D-D mixture is heated by a preheater by using system waste heat and then sent into the de-weighting tower.

Preferably, reboilers at the bottoms of the heavy component removal tower, the light component removal tower and the finished product tower are heated by steam PID automatic temperature control, and a heating medium is saturated steam with the pressure of 0.7 MPa.

Preferably, two condensers are arranged at the top of the light component removal tower and the finished product tower, the cooling medium is softened water at 30 ℃, and the water supply pressure is 0.4-0.6 MPa.

The technical scheme of the invention has the following beneficial technical effects:

(1) heavy components in the process mother liquor D-D mixed agent are firstly removed through a heavy component removal tower, then dichloropropane and light component impurities are separated from the top through a light component removal tower and can be recycled, materials at the bottom of the light component removal tower enter a finished product tower for mass transfer separation to obtain cis-1, 3-dichloropropene and trans-1, 3-dichloropropene, the product purity of the cis-1, 3-dichloropropene can reach more than 95%, and the content of the cis-1, 3-dichloropropene in the trans-1, 3-dichloropropene product is not more than 0.5%.

(2) The gas phase at the top of the heavy component removal tower is directly fed into the light component removal tower by adopting a gas phase fractional condensation technology, so that the energy can be saved by more than 20 percent.

(3) The D-D mixed agent rectification separation process adopts three towers for continuous operation and pressure swing operation and side line extraction, so that the product purity is high, the energy is saved, the D-D mixed agent of the process mother liquor is heated by the waste heat of a system through a preheater and then is fed into a de-heavy tower, the heat energy of the existing production system is fully utilized, the energy is further saved, and the separation efficiency of the D-D mixed agent of the process mother liquor in the de-heavy tower is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Detailed Description

The invention discloses a D-D mixture rectification separation process, which can be realized by appropriately improving process parameters by a person skilled in the art by referring to the content in the text. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention is further illustrated by the following examples:

the chloropropene is produced by the reaction of propylene and chlorine, and the reaction equation is as follows:

main reaction:

side reaction: CH (CH)₃-CH＝CH₂+Cl₂→CH₃-CHCl-CH₂Cl

CH₃-CH＝CH₂+Cl₂→CH₂Cl-CH＝CHCl+HCl

CH₃-CH＝CH₂+Cl₂→CH₃-CH₂-CH₂Cl+HCl

The main product is chloropropene, and byproducts D-D mixture and hydrochloric acid are also generated, wherein the components of the process mother liquor D-D mixture are as follows: 50.9 percent of light component plus dichloropropane, 19.5 percent of cis-1, 3-dichloropropene, 19 percent of trans-1, 3-dichloropropene and 10.6 percent of heavy component.

The D-D mixture rectification separation process comprises the following steps:

s102, under the condition of reduced pressure operation, feeding a process mother liquor D-D mixed agent obtained from the bottom of a chloropropene refining process tower into a de-weighting tower, heating by steam in a tower bottom reboiler, and carrying out mass transfer separation on easily-carbonized heavy components and light components in the process mother liquor D-D mixed agent in the de-weighting tower;

wherein the flow rate of the process mother liquor D-D mixture is 2100kg/h, and the components are as follows: 50.9 percent of light component plus dichloropropane, 19.5 percent of cis-1, 3-dichloropropene, 19 percent of trans-1, 3-dichloropropene and 10.6 percent of heavy component; the pressure at the top of the heavy component removal tower is 35KPa, the pressure at the bottom of the heavy component removal tower is 45KPa, the temperature at the top of the heavy component removal tower is 70.5 ℃, and the temperature at the bottom of the heavy component removal tower is 108 ℃.

S104, controlling reflux of the dichloropropene and light component evaporated gas phase by a fractional condenser at the top of the tower, directly feeding the non-condensable gas phase into a light component removal tower, and feeding heavy components at the bottom of the heavy component removal tower into a post-working section for treatment;

s106, under the condition of reduced pressure operation, feeding the top non-condensable gas phase of the heavy component removal tower into a light component removal tower, heating by steam through a tower bottom reboiler of the light component removal tower, and carrying out mass transfer separation on dichloropropane and light components and dichloropropylene in the light component removal tower;

wherein, the top non-condensable gas phase of the heavy component removal tower is directly sent into the light component removal tower, the gas phase fractional condensation technology is adopted, the energy is saved more by 20 percent, the top pressure of the light component removal tower is 32KPa, the bottom pressure of the light component removal tower is 44KPa, the top temperature of the light component removal tower is 59.1 ℃, and the bottom temperature of the light component removal tower is 81 ℃.

S108, allowing the dichloropropane and the light component evaporated gas phase to reach the top of a light component removal tower and be cooled by a condenser, allowing the condensate to enter a reflux tank, allowing part of the condensate to be sent to the tower for reflux, allowing part of the condensate to be sent to a warehouse for storage after cooling, and sending the tower bottom material of the light component removal tower to a finished product tower;

wherein, the number of the condensers is two, partial condensate entering the reflux tank is sent to a warehouse for storage after being cooled by a cooler, the flow of dichloropropane distilled from the tower top of the light component removal tower and light components is 1070kg/h, and the components comprise 99.5 percent of light components and dichloropropane and 0.5 percent of cis-1, 3-dichloropropene.

S110, under the vacuum operation condition, feeding the tower bottom material of the light component removal tower into a finished product tower, heating the tower bottom reboiler of the finished product tower by steam, then carrying out mass transfer separation on cis-form 1,3 dichloropropene in the finished product tower, cooling the cis-form 1,3 dichloropropene evaporated gas phase reaching the tower top of the finished product tower by a condenser, feeding a condensate into a cis-form tank, feeding part of the condensate into the tower for reflux, continuously distilling part of the condensate out of the tower top, cooling and then feeding the condensate into the cis-form finished product tank for storage;

wherein, the number of the condensers is two, partial condensate entering the cis-form tank is cooled by a cooler and then is sent to the cis-form finished product tank for storage, the pressure at the top of the finished product tower is 25KPa, the pressure at the bottom of the finished product tower is 37KPa, the temperature at the top of the tower is 64 ℃, the temperature at the bottom of the tower is 80 ℃, the flow of the cis-form finished product distilled from the top of the finished product tower is 409kg/h, and the components comprise light components plus dichloropropane 2.5%, cis-1, 3-dichloropropene 95.5% and trans-1, 3-dichloropropene.

S112, collecting the trans-1, 3-dichloropropene from the side line at the lower part of the finished product tower, cooling, sending into a trans-tank, sending into a trans-finished product tank for storage, and intermittently discharging heavy component residual liquid at the bottom of the finished product tower to a residual liquid tank.

Wherein, the cooler is adopted for cooling, the flow of the distilled trans-finished product at the side line at the lower part of the finished product tower is 385kg/h, the composition comprises 0.5 percent of cis-1, 3 dichloropropene, 98 percent of trans-1, 3 dichloropropene and 1.5 percent of heavy component, the flow of the heavy component residual liquid at the bottom of the tower is 236kg/h, the composition comprises 5 percent of trans-1, 3 dichloropropene and 95 percent of heavy component.

Heavy components in the process mother liquor D-D mixed agent are removed through a heavy component removal tower, dichloropropane and light component impurities are separated from the top through a light component removal tower, recycling can be achieved, materials at the bottom of the light component removal tower enter a finished product tower to be subjected to mass transfer separation, cis-form 1, 3-dichloropropene and trans-form 1, 3-dichloropropene are obtained, the product purity can reach more than 95%, the content of the cis-form 1, 3-dichloropropene in the trans-form 1, 3-dichloropropene product is not more than 0.5%, and the product value is improved. The D-D mixture rectification separation process adopts three-tower continuous operation, pressure swing operation and side line extraction, so that the product purity is high, and more energy is saved.

Further, the process mother liquor D-D mixture is heated by the waste heat of the system through a preheater and then sent to a de-weighting tower.

Furthermore, reboilers at the tower bottoms of the heavy component removal tower, the light component removal tower and the finished product tower are heated by steam PID automatic temperature control, and a heating medium is saturated steam with the pressure of 0.7 MPa.

Furthermore, two condensers are arranged at the top of the light component removal tower and the finished product tower, the cooling medium is softened water at 30 ℃, and the water supply pressure is 0.4-0.6 MPa.

The process mother liquor D-D mixed agent is heated by the waste heat of the system through the preheater and then is sent to the de-heavy tower, so that the heat energy of the existing production system is fully utilized, the energy is further saved, and the separation efficiency of the process mother liquor D-D mixed agent in the de-heavy tower is improved. Through steam PID automatic temperature control heating, temperature control is more accurate, and is energy-conserving, establishes two condensers and has further ensured the condensation effect, on the whole, has further promoted the rectification separation effect, has practiced thrift the energy.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.