阅读说明：本技术 均四甲苯的生产方法 (Production method of durene ) 是由 冯海涛 马剑峰 冯佰荣 于 2021-02-05 设计创作，主要内容包括：本发明公开了一种均四甲苯的生产方法,包括以下步骤：S1、将均四甲苯母液加入结晶釜中获得均四甲苯晶体混合液；S2、将均四甲苯晶体混合液加入压滤机中获得均四甲苯滤饼；S3、将均四甲苯滤饼计入粉碎机中,获得均四甲苯块状物料；S4、将均四甲苯块状物料和压滤获得的滤液加入搅拌釜中获得均四甲苯结晶体物料；S5、将均四甲苯结晶体物料加入压榨机中获得均四甲苯固体饼；S6、将获均四甲苯固体饼加入粉碎机中获得均四甲苯成品。本发明全程密闭输送,依次经过冷冻结晶、压滤、第一次粉碎、搅拌、压榨、第二次粉碎生产出均四甲苯,生产出产品纯度达到99％的均四甲苯,该工艺流程短、生产成本低、产品纯度高。(The invention discloses a production method of durene, which comprises the following steps: s1, adding the durene mother liquor into a crystallization kettle to obtain durene crystal mixed liquor; s2, adding the durene crystal mixed solution into a filter press to obtain a durene filter cake; s3, adding the durene filter cake into a crusher to obtain a durene block material; s4, adding the durene massive material and filtrate obtained by filter pressing into a stirring kettle to obtain durene crystal material; s5, adding the durene crystal material into a squeezer to obtain a durene solid cake; and S6, adding the durene solid cake into a crusher to obtain a durene finished product. The invention carries out the whole process of closed conveying, and durene is produced by freezing crystallization, filter pressing, primary crushing, stirring, squeezing and secondary crushing in sequence, and the produced durene has the product purity of 99 percent, and the process flow is short, the production cost is low and the product purity is high.)

1. The production method of durene is characterized by comprising the following steps:

s1, freezing and crystallizing: adding the durene mother liquor into a crystallization kettle, and freezing and crystallizing to obtain durene crystal mixed liquor;

s2, filter pressing: adding the durene crystal mixed liquid obtained in the step S1 into a filter press, and performing filter pressing to obtain a durene filter cake;

s3, first crushing: adding the durene filter cake obtained in the step S2 into a crusher, and crushing to obtain durene block-shaped materials;

s4, stirring: adding the durene blocky material obtained in the step S3 and the filtrate obtained by filter pressing in the step S2 into a stirring kettle, and stirring to obtain a durene crystal material;

s5, squeezing: adding the durene crystal material obtained in the step S4 into a squeezer, and squeezing to obtain a durene solid cake;

s6, second crushing: and (4) adding the durene solid cake obtained in the step (S5) into a crusher, and crushing to obtain a durene finished product.

2. The process for producing durene according to claim 1, wherein the durene solution in step S1 is obtained by rectifying a C10 raw material and cutting a cut fraction at 190 to 200 ℃, and the durene solution contains 18 to 28% durene.

3. The method for producing durene according to claim 1, wherein the cold-freezing crystallization in step S1 is carried out at a temperature of-20 ℃ to-30 ℃, for a time of 6 to 12 hours, and the stirring speed of the crystallization vessel is 34 r/min.

4. The process for producing durene according to claim 1, wherein the pressure filtration pass in step S2 comprises the steps of:

s21, feeding, pumping durene crystal mixed liquid obtained through cooling crystallization into a liquid inlet of a filter plate by a plunger pump, filling the filter chamber with the durene crystal mixed liquid, intercepting durene crystals by filter cloth after the filter cloth permeates, and opening an outlet valve at the lower part after observing that liquid oil overflows from an oil filtering discharge port on the filter plate through a sight glass in order to ensure that the durene crystal mixed liquid can fill a cavity between the filter plates and form a uniform filter cake;

s22, filtering, wherein when the feeding is finished, a liquid oil relevant valve is opened, and then the liquid oil relevant valve enters a filtering stage, solid-phase durene crystals are intercepted by filter cloth during filtering, and the end point of the filtering stage is finished when the oil inlet pressure reaches 0.2 Mpa;

s23, extruding, when the oil inlet pump is stopped, the extrusion stage is started, the extrusion material is input into the membrane plate, the membrane plate expands to extrude the material to form a durene filter cake, the filtrate is separated from the durene filter cake, and the extrusion stage is finished when the pressure reaches 0.8 Mpa;

s24, after extrusion is finished, stopping extruding the material, gradually releasing pressure to 0.3Mpa, and starting purging the liquid oil pipeline; blowing oil in the liquid oil line pipe to a first intermediate tank of solvent oil, and conveying the oil to an SA-1500 solvent closed product pipe by using a plunger pump; after blowing, the pressure is continuously released to 0Mpa, and the filter plate is opened to obtain a filter cake.

5. The durene production method according to claim 1, wherein the grain size of the durene block obtained by the pulverization in step S3 is 5 to 8 cm.

6. The process for producing durene according to claim 1, characterized in that the pressing process in step S5 includes the steps of: and setting the extrusion pressure to be 20-22 MPa, and the extrusion time to be 50-80 min, conveying the obtained durene crystal material into a squeezer through a plunger pump, removing solvent oil in the squeezing process, conveying the solvent oil into a second intermediate tank, conveying 70% of the solvent oil into a crystallization kettle through the plunger pump for reuse, and conveying 30% of the solvent oil into a stirring kettle through the plunger pump for reuse as a stirring liquid.

7. The production method of durene according to claim 1, wherein the grain size of the durene product obtained by the pulverization in step S6 is 2 to 5 cm.

Technical Field

The invention belongs to the technical field of durene purification, and particularly relates to a durene production method.

Background

Durene, also known as durene, is an important organic chemical raw material with the chemical name of 1,2,4, 5-tetramethylbenzene. The method is mainly used for producing pyromellitic dianhydride (1,2,4, 5-benzoic dianhydride, PMDA), which is an important raw material for producing polyimide polymer, and the polyimide is a novel synthetic material with high temperature resistance, low temperature resistance, radiation resistance, impact resistance, excellent electrical property and mechanical property, and has important application irreplaceable for other engineering plastics in aerospace and electromechanical industries. With the increasing market usage of polyimide, durene is used as the main raw material for synthesizing polyimide, and the demand is increasing. The production line of durene is divided into two types, one type is a chemical synthesis method, including an isomerization method, an alkylation method, a disproportionation reaction method and the like, and the synthesis method not only has complex process but also has higher cost; the other is a separation and purification method, which takes byproducts in the processing process of petroleum and coal, mainly C10 heavy aromatics as raw materials for separation and purification. The resource of C10 in China is rich, and catalytic reforming devices in oil refineries, wide-cut catalytic reforming devices in polyester plants, ethylene devices, coal high-temperature coking devices and the like are provided. For domestic enterprises, durene with high added value is extracted from C10, so that remarkable economic benefit can be brought to the enterprises.

The original durene except the freezing crystallization kettle is consistent with the existing crystallization equipment in quantity, the centrifugal and squeezing equipment is more in number, a large amount of manual operation is needed in the operation processes of centrifugal and squeezing, shaking, discharging and the like, and the labor intensity of workers is higher. Secondly, the most serious problems of the squeezing process are the problems of safety, environmental protection and occupational health, squeezing is basically carried out under open environmental conditions, the production environment is severe, certain harm is caused to the physical health of operators, and the normal operation of enterprises is seriously influenced by the unorganized discharge of VOCs.

Therefore, a simple, effective and easily industrialized technical route has great significance.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a production method of durene.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention provides a production method of durene, which comprises the following steps:

s1, freezing and crystallizing: adding the durene mother liquor into a crystallization kettle, and freezing and crystallizing to obtain durene crystal mixed liquor;

s2, filter pressing: adding the durene crystal mixed liquid obtained in the step S1 into a filter press, and performing filter pressing to obtain a durene filter cake;

s3, first crushing: adding the durene filter cake obtained in the step S2 into a crusher, and crushing to obtain durene block-shaped materials;

s4, stirring: adding the durene blocky material obtained in the step S3 and the filtrate obtained by filter pressing in the step S2 into a stirring kettle, and stirring to obtain a durene crystal material;

s5, squeezing: adding the durene crystal material obtained in the step S4 into a squeezer, and squeezing to obtain a durene solid cake;

s6, second crushing: and (4) adding the durene solid cake obtained in the step (S5) into a crusher, and crushing to obtain a durene finished product.

As a preferable technical scheme of the invention, the durene solution in the step S1 is obtained by rectifying and cutting a C10 raw material into a cut fraction at 190-200 ℃, and the durene solution contains 18-28% of durene.

As a preferred technical scheme of the invention, the cold freezing process in the step S1 is to freeze the mixture to-20 to-30 ℃, the freezing time is 6 to 12 hours, and the stirring speed of the crystallization kettle is 34 r/min.

As a preferred embodiment of the present invention, the pressure filtration process in step S2 includes the following steps:

s21, feeding, pumping durene crystal mixed liquid obtained through cooling crystallization into a liquid inlet of a filter plate by a plunger pump, filling the filter chamber with the durene crystal mixed liquid, intercepting durene crystals by filter cloth after the filter cloth permeates, and opening an outlet valve at the lower part after observing that liquid oil overflows from an oil filtering discharge port on the filter plate through a sight glass in order to ensure that the durene crystal mixed liquid can fill a cavity between the filter plates and form a uniform filter cake;

s22, filtering, wherein when the feeding is finished, a liquid oil relevant valve is opened, and then the liquid oil relevant valve enters a filtering stage, solid-phase durene crystals are intercepted by filter cloth during filtering, and the end point of the filtering stage is finished when the oil inlet pressure reaches 0.2 Mpa;

s23, extruding, when the oil inlet pump is stopped, the extrusion stage is started, the extrusion material is input into the membrane plate, the membrane plate expands to extrude the material to form a durene filter cake, the filtrate is separated from the durene filter cake, and the extrusion stage is finished when the pressure reaches 0.8 Mpa;

s24, after extrusion is finished, stopping extruding the material, gradually releasing pressure to 0.3Mpa, and starting purging the liquid oil pipeline; blowing oil in the liquid oil line pipe to a first intermediate tank of solvent oil, and conveying the oil to an SA-1500 solvent closed product pipe by using a plunger pump; after blowing, the pressure is continuously released to 0Mpa, and the filter plate is opened to obtain a filter cake.

As a preferable technical scheme of the invention, the durene block-shaped material obtained by crushing in the step S3 has a particle size of 5-8 cm.

As a preferred technical solution of the present invention, the pressing process in step S5 includes the following steps: and setting the extrusion pressure to be 20-22 MPa, and the extrusion time to be 50-80 min, conveying the obtained durene crystal material into a squeezer through a plunger pump, removing solvent oil in the squeezing process, conveying the solvent oil into a second intermediate tank, conveying 70% of the solvent oil into a crystallization kettle through the plunger pump for reuse, and conveying 30% of the solvent oil into a stirring kettle through the plunger pump for reuse as a stirring liquid.

As a preferable technical scheme of the invention, the grain diameter of the durene finished product obtained by crushing in the step S6 is 2-5 cm.

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

firstly, the method takes C10 as a raw material, and produces durene with the product purity of 99 percent by rectification, freezing crystallization, filter pressing, primary crushing, stirring, squeezing and secondary crushing.

Secondly, the crystallization time is 6-12 hours, the crystallization time is short, durene cannot be fully separated out of the solution, but the time is too long, cold energy is wasted, and the production cost is correspondingly increased.

Thirdly, in the crystallization process, crystal nuclei are generated in the solution, solute molecules are arranged layer by layer to form crystal grains after the crystal nuclei grow, the crystal growth is that the solute is diffused in the first step, and the solute to be crystallized passes through a static liquid layer on the crystallization surface by diffusion and is transferred to the crystal surface from the solution; the second step is surface reaction, the solute on the surface of the crystal is embedded into the crystal face, the crystal grows, and the contact between the solute and the crystal face is increased by stirring. The stirring speed has an influence on the crystal growth speed, and the reaction rate is accelerated. The stirring speed is too low, and the crystallization kettle surface easily forms the wall built-up, is unfavorable for the cooling to the material. The stirring speed of the crystallization kettle is 34 r/min.

And fourthly, the squeezing procedure is the last defense line for ensuring the qualified product quality, and the full squeezing time and pressure can ensure that the oil in the material flows out fully, so that the finished product reaches the purity requirement, but the squeezing pressure and time are not longer, the longer the squeezing time is, the better the squeezing time is, the overlong energy is wasted, and the cost is increased.

Drawings

FIG. 1 is a flow chart of the process for producing durene according to the invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Example 1

In order to achieve the object of the present invention, as shown in fig. 1, there is provided a method for producing durene, comprising the steps of:

s1, freezing and crystallizing: adding the durene mother liquor into a crystallization kettle, and freezing and crystallizing to obtain durene crystal mixed liquor; wherein, the durene mother liquor is obtained by rectifying the C10 raw material and cutting a cut fraction at 190 ℃, the durene mother liquor contains 18 percent of durene, the freezing and crystallization process is freezing to-20 ℃, the freezing time is 6 hours, and the stirring speed of a crystallization kettle is 34 r/min.

S2, filter pressing: adding the durene crystal mixed liquid obtained in the step S1 into a filter press, and performing filter pressing to obtain a durene filter cake; wherein, the filter pressing process comprises the following steps: s21, feeding, pumping durene crystal mixed liquid obtained through cooling crystallization into a liquid inlet of a filter plate by a plunger pump, filling the filter chamber with the durene crystal mixed liquid, intercepting durene crystals by filter cloth after the filter cloth permeates, and opening an outlet valve at the lower part after observing that liquid oil overflows from an oil filtering discharge port on the filter plate through a sight glass in order to ensure that the durene crystal mixed liquid can fill a cavity between the filter plates to form a uniform filter cake; s22, filtering, wherein when the feeding is finished, a liquid oil relevant valve is opened, and then the liquid oil relevant valve enters a filtering stage, solid-phase durene crystals are intercepted by filter cloth during filtering, and the end point of the filtering stage is finished when the oil inlet pressure reaches 0.2 Mpa; s23, extruding, when the oil inlet pump is stopped, the extrusion stage is started, the extrusion material is input into the membrane plate, the membrane plate expands to extrude the material to form a durene filter cake, the filtrate is separated from the durene filter cake, and the extrusion stage is finished when the pressure reaches 0.8 Mpa; s24, after extrusion is finished, stopping extruding the material, gradually releasing pressure to 0.3Mpa, and starting purging the liquid oil pipeline; blowing oil in the liquid oil line pipe to a first intermediate tank of solvent oil, and conveying the oil to an SA-1500 solvent closed product pipe by using a plunger pump; after blowing, the pressure is continuously released to 0Mpa, and the filter plate is opened to obtain a filter cake.

S3, first crushing: the durene filter cake obtained in the step S2 is added into a crusher and crushed to obtain durene block-shaped materials; the particle size of the durene block material is 5 cm.

S4, stirring: adding the durene blocky material obtained in the step S3 and the filtrate obtained by filter pressing in the step S2 into a stirring kettle, and stirring to obtain a durene crystal material;

s5, squeezing: adding the durene crystal material obtained in the step S4 into a squeezer, and squeezing to obtain a durene solid cake; wherein, the squeezing process comprises the following steps: and setting the extrusion pressure to be 20MPa and the extrusion time to be 50min, conveying the obtained durene crystal material into a squeezer through a plunger pump, removing solvent oil in the squeezing process, conveying the solvent oil into a second intermediate tank, conveying 70% of the solvent oil into a crystallization kettle through the plunger pump for recycling, and conveying 30% of the solvent oil into a stirring kettle through the plunger pump for recycling as stirring liquid.

S6, second crushing: and (4) adding the durene solid cake obtained in the step (S5) into a crusher, and crushing to obtain a durene finished product. The grain diameter of the durene finished product is 2 cm.

Example 2

As a second embodiment, this example provides a method for producing durene, including the steps of:

s1, freezing and crystallizing: adding durene solution into a crystallization kettle, and freezing and crystallizing to obtain durene crystal mixed solution; wherein, the durene solution is obtained by rectifying the C10 raw material and cutting the cut fraction at 200 ℃, the durene solution contains 28 percent of durene, the freezing and crystallization process is freezing to-30 ℃, the freezing time is 12 hours, and the stirring speed of the crystallization kettle is 34 r/min.

S2, filter pressing: adding the durene crystal mixed liquid obtained in the step S1 into a filter press, and performing filter pressing to obtain a durene filter cake; wherein, the filter pressing process comprises the following steps: s21, feeding, pumping durene crystal mixed liquid obtained through cooling crystallization into a liquid inlet of a filter plate by a plunger pump, filling the filter chamber with the durene crystal mixed liquid, intercepting durene crystals by filter cloth after the filter cloth permeates, and opening an outlet valve at the lower part after observing that liquid oil overflows from an oil filtering discharge port on the filter plate through a sight glass in order to ensure that the durene crystal mixed liquid can fill a cavity between the filter plates and form a uniform filter cake; s22, filtering, wherein when the feeding is finished, a liquid oil relevant valve is opened, and then the liquid oil relevant valve enters a filtering stage, solid-phase durene crystals are intercepted by filter cloth during filtering, and the end point of the filtering stage is finished when the oil inlet pressure reaches 0.2 Mpa; s23, extruding, when the oil inlet pump is stopped, the extrusion stage is started, the extrusion material is input into the membrane plate, the membrane plate expands to extrude the material to form a durene filter cake, the filtrate is separated from the durene filter cake, and the extrusion stage is finished when the pressure reaches 0.8 Mpa; s24, after extrusion is finished, stopping extruding the material, gradually releasing pressure to 0.3Mpa, and starting purging the liquid oil pipeline; blowing oil in the liquid oil line pipe to a first intermediate tank of solvent oil, and conveying the oil to an SA-1500 solvent closed product pipe by using a plunger pump; after blowing, the pressure is continuously released to 0Mpa, and the filter plate is opened to obtain a filter cake.

S3, first crushing: the durene filter cake obtained in the step S2 is added into a crusher and crushed to obtain durene block-shaped materials; the particle size of the durene block material is 8 cm.

S4, stirring: adding the durene blocky material obtained in the step S3 and the filtrate obtained by filter pressing in the step S2 into a stirring kettle, and stirring to obtain a durene crystal material;

s5, squeezing: adding the durene crystal material obtained in the step S4 into a squeezer, and squeezing to obtain a durene solid cake; wherein, the squeezing process comprises the following steps: and setting the extrusion pressure to be 22MPa and the extrusion time to be 80min, conveying the obtained durene crystal material into a squeezer through a plunger pump, removing solvent oil in the squeezing process, conveying the solvent oil into a second intermediate tank, conveying 70% of the solvent oil into a crystallization kettle through the plunger pump for recycling, and conveying 30% of the solvent oil into a stirring kettle through the plunger pump for recycling as stirring liquid.

S6, second crushing: and (4) adding the durene solid cake obtained in the step (S5) into a crusher, and crushing to obtain a durene finished product. The grain diameter of the durene finished product is 5 cm.

Example 3

As a third embodiment, this example provides a method for producing durene, including the steps of:

s1, freezing and crystallizing: adding durene solution into a crystallization kettle, and freezing and crystallizing to obtain durene crystal mixed solution; wherein, the durene solution is obtained by rectifying the C10 raw material and cutting off the fraction of 195 ℃, the durene solution contains 20 percent of durene, the freezing and crystallization process is freezing to-26 ℃, the freezing time is 8 hours, and the stirring speed of the crystallization kettle is 34 r/min.

S2, filter pressing: adding the durene crystal mixed liquid obtained in the step S1 into a filter press, and performing filter pressing to obtain a durene filter cake; wherein, the filter pressing process comprises the following steps: s21, feeding, pumping durene crystal mixed liquid obtained through cooling crystallization into a liquid inlet of a filter plate by a plunger pump, filling the filter chamber with the durene crystal mixed liquid, intercepting durene crystals by filter cloth after the filter cloth permeates, and opening an outlet valve at the lower part after observing that liquid oil overflows from an oil filtering discharge port on the filter plate through a sight glass in order to ensure that the durene crystal mixed liquid can fill a cavity between the filter plates and form a uniform filter cake; s22, filtering, wherein when the feeding is finished, a liquid oil relevant valve is opened, and then the liquid oil relevant valve enters a filtering stage, solid-phase durene crystals are intercepted by filter cloth during filtering, and the end point of the filtering stage is finished when the oil inlet pressure reaches 0.2 Mpa; s23, extruding, when the oil inlet pump is stopped, the extrusion stage is started, the extrusion material is input into the membrane plate, the membrane plate expands to extrude the material to form a durene filter cake, the filtrate is separated from the durene filter cake, and the extrusion stage is finished when the pressure reaches 0.8 Mpa; s24, after extrusion is finished, stopping extruding the material, gradually releasing pressure to 0.3Mpa, and starting purging the liquid oil pipeline; blowing oil in the liquid oil line pipe to a first intermediate tank of solvent oil, and conveying the oil to an SA-1500 solvent closed product pipe by using a plunger pump; after blowing, the pressure is continuously released to 0Mpa, and the filter plate is opened to obtain a filter cake.

S3, first crushing: the durene filter cake obtained in the step S2 is added into a crusher and crushed to obtain durene block-shaped materials; the particle size of the durene block material is 6 cm.

S4, stirring: adding the durene blocky material obtained in the step S3 and the filtrate obtained by filter pressing in the step S2 into a stirring kettle, and stirring to obtain a durene crystal material;

s5, squeezing: adding the durene crystal material obtained in the step S4 into a squeezer, and squeezing to obtain a durene solid cake; wherein, the squeezing process comprises the following steps: and setting the extrusion pressure to be 21MPa and the extrusion time to be 60min, conveying the obtained durene crystal material into a squeezer through a plunger pump, removing solvent oil in the squeezing process, conveying the solvent oil into a second intermediate tank, conveying 70% of the solvent oil into a crystallization kettle through the plunger pump for recycling, and conveying 30% of the solvent oil into a stirring kettle through the plunger pump for recycling as stirring liquid.

S6, second crushing: and (4) adding the durene solid cake obtained in the step (S5) into a crusher, and crushing to obtain a durene finished product. The grain diameter of the durene finished product is 4 cm.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.