System and process for separating high-purity unsym-trimethylbenzene and enriching sym-trimethylbenzene

Abstract

The invention provides a system and a process for separating high-purity unsym-trimethylbenzene and enriching mesitylene. The system comprises a pre-fractionating tower, an unsym-trimethylbenzene tower, a sym-trimethylbenzene light component removal tower and a sym-trimethylbenzene heavy component removal tower, a material inlet and a mesitylene mixed material outlet are formed in the side wall of the pre-fractionating tower, a first material outlet is formed in the tower top, and a mesitylene mixed material outlet is formed in the tower bottom; the side wall of the unsym-trimethylbenzene tower is provided with an unsym-trimethylbenzene mixed material inlet, the unsym-trimethylbenzene mixed material inlet is connected with the unsym-trimethylbenzene mixed material outlet, the tower top is provided with an unsym-trimethylbenzene outlet, and the tower bottom is provided with a second material outlet; the side wall of the sym-trimethylbenzene light component removal tower is provided with a sym-trimethylbenzene mixed material inlet, the sym-trimethylbenzene mixed material inlet is connected with the sym-trimethylbenzene mixed material outlet, the tower top is provided with a third material outlet, and the tower bottom is provided with a sym-trimethylbenzene coarse material outlet; the side wall of the sym-trimethylbenzene heavy component removal tower is provided with a sym-trimethylbenzene coarse material inlet, the sym-trimethylbenzene coarse material inlet is connected with the sym-trimethylbenzene coarse material outlet, the tower top is provided with an enriched sym-trimethylbenzene material outlet, and the tower bottom is provided with a fourth material outlet.

Description

Technical Field

[0001] The present invention relates to the technical field of C9 aromatic mixture separation, and in particular to a system and process for separating high-purity trimethylolbenzene and enriching mesitylene. Background Art

[0002] The continuous reforming unit of aromatics in refineries produces C9 aromatics as a by-product, of which the mass fraction of trimethylbenzene in C9 aromatics can reach 20%~40%. Trimethylbenzene products can be obtained through distillation separation, which has become the main way to produce trimethylbenzene in China.

[0003] Mesitylene is an important raw material for organic synthesis. The more representative methods for producing mesitylene include isomerization-distillation of mesitylene, extractive distillation, alkylation-distillation, etc. The separation of C9 aromatic mixtures in China mostly adopts a double-tower process or a three-tower process to produce mesitylene with a purity of more than 99% and co-produce more than 35% of enriched mesitylene. The enriched mesitylene is used as a raw material for catalytic alkylation reaction to obtain high-purity mesitylene. However, the mesitylene in the heavy aromatics of this process cannot be directly utilized, which is not economical. At the same time, there are problems such as high price of alkylating agent propylene, large consumption of propylene and energy caused by secondary alkylation, and serious equipment corrosion. The extractive distillation method for producing mesitylene is the most representative process technology. Its basic principle is to add an extractant to the separated system to increase the relative volatility of mesitylene and o-methylethylbenzene, and then separate high-purity mesitylene by distillation. The advantage of this process is that it can directly utilize mesitylene in heavy aromatics, but in order to extract high-purity mesitylene, the total content of mesitylene and o-methylethylbenzene in the mixture entering the mesitylene extraction tower is required to be greater than 99%. However, the existing process for separating C9 aromatics to obtain enriched mesitylene in the mixture contains more other light and heavy components. The total mass content of mesitylene and o-methylethylbenzene in the mixture obtained by the current process accounts for about 35% to 40%, especially the presence of components with lower boiling points than mesitylene, so it cannot be directly treated by extraction. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a system and process for separating high-purity partial trimethylolene and enriching mesitylene.

[0005] In one aspect of the present invention, the present invention provides a system for separating high-purity partial trimethylol and enriching mesitylene. According to an embodiment of the present invention, the system comprises: a pre-fractionation tower, a partial trimethylol tower, a mesitylene light removal tower and a mesitylene heavy removal tower; The side wall of the pre-fractionation tower is provided with a material inlet, the side wall of the pre-fractionation tower above the material inlet is provided with a mesitylene mixed material outlet, the top of the pre-fractionation tower is provided with a first material outlet, the bottom of the pre-fractionation tower is provided with a partial trimethylol mixed material outlet, and the bottom of the pre-fractionation tower is provided with a first heating element; The side wall of the partial trimethylol tower is provided with a partial trimethylol mixing inlet, the partial trimethylol mixing inlet is connected to the mesitylene mixing outlet of the pre-fractionation tower, the top of the partial trimethylol tower is provided with a partial trimethylol outlet, the bottom of the partial trimethylol tower is provided with a second material outlet, and the bottom end of the partial trimethylol tower is provided with a second heating element; The side wall of the mesitylene delightening tower is provided with a mesitylene mixing inlet, the mesitylene mixing outlet is connected to the mesitylene mixing inlet, the top of the mesitylene delightening tower is provided with a third material outlet, the bottom of the mesitylene delightening tower is provided with a mesitylene crude material outlet, and the bottom end of the mesitylene delightening tower is provided with a third heating element; The side wall of the isocyanate deweighting tower is provided with an inlet for crude isocyanate material, the inlet for crude isocyanate material is connected with the outlet for crude isocyanate material, the top of the isocyanate deweighting tower is provided with an outlet for enriched isocyanate material, the bottom of the isocyanate deweighting tower is provided with a fourth material outlet, and the bottom end of the isocyanate deweighting tower is provided with a fourth heating element.

[0006] According to the system for separating high-purity trimethylolbenzene and enriching mesitylene of the above embodiment of the present invention, the C9 aromatic mixture enters the pre-fractionation tower from the material inlet for pre-fractionation, and the low-boiling-point components in the C9 aromatic mixture are discharged from the first material outlet and sent to the tank area as S1000# product. Trimethylolbenzene and components with higher boiling points than it are sent from the trimethylolbenzene mixed material outlet to the trimethylolbenzene tower through the trimethylolbenzene mixed material inlet for fractionation, and the obtained high-purity trimethylolbenzene is discharged from the trimethylolbenzene outlet. Specifically, the purity of the trimethylolbenzene is not less than 99wt%, and the obtained heavy aromatic solvent oil is discharged from the second material outlet. The side wall of the pre-fractionation tower above the material inlet is provided with a mesitylene mixture outlet. The inventors have found that the mesitylene concentration of the tower plate distributed at the above-mentioned mesitylene mixture outlet is high, and a mesitylene-enriched mixture can be obtained. The mesitylene-enriched mixture passes through the mesitylene mixture outlet of the pre-fractionation tower and the mesitylene mixture inlet to enter the mesitylene-tri-light removal tower for fractionation. The components below the boiling point of mesitylene (and o-methylethylbenzene) are discharged from the third material outlet and sent to the tank area as S1000# products. The remaining components are distilled from the mesitylene crude material outlet through the mesitylene crude material inlet to the mesitylene-tri-heavy removal tower. The mesitylene and o-methylethylbenzene components are discharged from the mesitylene enriched material outlet. Specifically, the total mass proportion of mesitylene and o-methylethylbenzene in the mixture discharged from the mesitylene enriched material outlet is not less than 99%, which can be directly sent to the extractive distillation lower tower. The obtained heavy aromatic solvent oil is discharged from the fourth material outlet and returned to the trimethylol tower to recover trimethylol or directly used as S1000# products. Therefore, the system can effectively separate the C9 aromatic hydrocarbon mixture to obtain trimethylolus with a purity of not less than 99wt%, and the recovery rate of trimethylolus is not less than 90%, as well as a mixture of trimethylolus and o-methylethylbenzene with a total content of trimethylolus and o-methylethylbenzene of 99% or more. The above-mentioned mixture of trimethylolus and o-methylethylbenzene can be directly used as the raw material of the extractive distillation tower, thereby improving the utilization rate of the components, reducing the investment in equipment and materials, and simplifying the operation process.

[0007] In addition, the system for separating high-purity partial trimethylolene and enriching mesitylene according to the above embodiment of the present invention may also have the following technical features: In some embodiments of the present invention, the first material outlet of the pre-fractionation tower is connected to a first reflux device.

[0008] In some embodiments of the present invention, the trimethylolbenzene outlet of the trimethylolbenzene tower is connected to a second reflux device.

[0009] In some embodiments of the present invention, the third material outlet of the homopolymerization and triple-delightening tower is connected to a third reflux device.

[0010] In some embodiments of the present invention, the outlet of the mesitylene-enriched material of the mesitylene deweighting tower is connected to a fourth reflux device.

[0011] In some embodiments of the present invention, the first reflux device includes a pre-fractionation tower condensation component, a first reflux tank, a pre-fractionation tower vacuum pump and a pre-fractionation tower reflux pump, the first material outlet is connected to the first reflux tank inlet, the pre-fractionation tower condensation component is arranged between the first material outlet and the first reflux tank inlet, the pre-fractionation tower vacuum pump is connected to the first reflux tank, the first reflux tank outlet is connected to the pre-fractionation tower reflux pump, a part of the material is discharged through the pre-fractionation tower reflux pump, and the other part is refluxed to the pre-fractionation tower from the first reflux inlet at the upper end of the pre-fractionation tower.

[0012] In some embodiments of the present invention, the second reflux device includes a second reflux tank and a trimethylolbenzene tower reflux pump, the trimethylolbenzene outlet is connected to the second reflux tank inlet, the second reflux tank outlet is connected to the trimethylolbenzene tower reflux pump, a part of the material is discharged through the trimethylolbenzene tower reflux pump, and the other part is refluxed to the trimethylolbenzene tower from the second reflux inlet at the upper end of the trimethylolbenzene tower.

[0013] In some embodiments of the present invention, the third reflux device includes a uniform three-delightening tower condensation component, a third reflux tank, a uniform three-delightening tower vacuum pump and a uniform three-delightening tower reflux pump, the third material outlet is connected to the third reflux tank inlet, the uniform three-delightening tower condensation component is arranged between the third material outlet and the third reflux tank inlet, the uniform three-delightening tower vacuum pump is connected to the third reflux tank, the third reflux tank outlet is connected to the uniform three-delightening tower reflux pump, a part of the material is discharged through the uniform three-delightening tower reflux pump, and the other part is refluxed to the uniform three-delightening tower from the third reflux inlet at the upper end of the uniform three-delightening tower.

[0014] In some embodiments of the present invention, the fourth reflux device includes a fourth reflux tank and a trimethylol degassing tower reflux pump, the outlet of the enriched trimethylol material is connected to the inlet of the fourth reflux tank, the outlet of the fourth reflux tank is connected to the trimethylol degassing tower reflux pump, a part of the material is discharged through the trimethylol degassing tower reflux pump, and the other part is refluxed to the trimethylol degassing tower from the fourth reflux inlet at the upper end of the trimethylol degassing tower.

[0015] In some embodiments of the present invention, the trimethylolbenzene outlet is connected to a first auxiliary heating component, and the high-temperature gas phase discharged from the trimethylolbenzene outlet is used to provide heat to the pre-fractionation tower through the first auxiliary heating component.

[0016] In some embodiments of the present invention, the enriched mesitylene material outlet is connected to a second auxiliary heating component, and the high-temperature gas phase discharged from the enriched mesitylene material outlet is used to provide heat to the mesitylene-removal tower through the second auxiliary heating component.

[0017] In some embodiments of the present invention, the pre-fractionation tower, the trimelene tower, the homo-trimethylbenzene light-removal tower, and the homo-trimethylbenzene heavy-removal tower each independently use 8-stage packing.

[0018] In some embodiments of the present invention, the material inlet of the pre-fractionation tower is arranged at the lower part of the second stage packing and the upper part of the third stage packing.

[0019] In some embodiments of the present invention, the mesitylene mixed material outlet of the pre-fractionation tower is arranged at the lower part of the first stage packing and the upper part of the second stage packing.

[0020] In some embodiments of the present invention, the mesitylene mixed material inlet of the mesitylene removal tower is arranged at the lower part of the second stage packing and the upper part of the third stage packing.

[0021] In some embodiments of the present invention, the mesitylene crude material inlet of the mesitylene deweighting tower is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing.

[0022] In some embodiments of the present invention, the trimethylolene mixed material inlet of the trimethylolene tower is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing.

[0023] In some embodiments of the present invention, a pre-fractionation tower kettle pump is provided between the partial trimethylolene mixed material inlet and the partial trimethylolene mixed material outlet of the partial trimethylolene tower.

[0024] In some embodiments of the present invention, the second material outlet of the trimethylol tower is connected to the trimethylol tower kettle pump.

[0025] In some embodiments of the present invention, a mesitylene-delightening tower kettle pump is provided between the mesitylene crude material outlet and the mesitylene crude material inlet.

[0026] In some embodiments of the present invention, the fourth material outlet is connected to the kettle pump of the triple deweighting tower.

[0027] In some embodiments of the present invention, the material inlet is connected to a pre-fractionation tower feed preheating element.

[0028] In another aspect of the present invention, the present invention proposes a process for separating high-purity trimethylolbenzene and enriching mesitylene using the above system. According to an embodiment of the present invention, the process comprises: The C9 aromatic hydrocarbon mixture enters the pre-fractionation tower from the material inlet, and the trimethylol mixed material enters the trimethylol tower from the trimethylol mixed material outlet of the pre-fractionation tower through the trimethylol mixed material inlet for fractionation to obtain trimethylol; The material containing mesitylene enters a mesitylene-delightening tower from the mesitylene mixed material outlet of the pre-fractionation tower through the mesitylene mixed material inlet for distillation. The mesitylene crude material obtained by distillation in the mesitylene-delightening tower enters a mesitylene-deheavy tower from the mesitylene crude material outlet through the mesitylene crude material inlet for distillation to obtain a mixture of mesitylene and o-methylethylbenzene.

[0029] Therefore, the method can achieve effective separation of the C9 aromatic hydrocarbon mixture, and obtain trimethylolus with a purity of not less than 99wt% and a mixture of trimethylolus and o-ethylmethylbenzene with a total content of mesitylene and o-ethylmethylbenzene of not less than 99%. The above-mentioned mixture of trimethylolus and o-ethylmethylbenzene can be directly used as a raw material for an extractive distillation tower.

[0030] In addition, the process according to the above embodiment of the present invention may also have the following technical features: In some embodiments of the present invention, the pressure of the pre-fractionation tower is 8 KPa-30 KPa, and the temperature of the top of the pre-fractionation tower is 82° C.-119° C.

[0031] In some embodiments of the present invention, the pressure of the trimethylolbenzene tower is 120 KPa-200 KPa, and the temperature of the top of the trimethylolbenzene tower is 176° C.-199° C.

[0032] In some embodiments of the present invention, the pressure of the homogenizing and degassing tower is 15KPa~30KPa, and the temperature of the top of the homogenizing and degassing tower is 99℃~120℃.

[0033] In some embodiments of the present invention, the pressure of the homogenizing and degassing tower is 120KPa~200KPa, and the temperature of the top of the homogenizing and degassing tower is 171℃~195℃.

[0034] In some embodiments of the present invention, the purity of the obtained trimethylol is not less than 99 wt %.

[0035] In some embodiments of the present invention, the mass percentage of the total amount of mesitylene and o-ethylmethylbenzene in the obtained mixture of mesitylene and o-ethylmethylbenzene is not less than 99wt%.

[0036] In some embodiments of the present invention, the mass proportion of mesitylene in the obtained mixture of mesitylene and o-methylethylbenzene is not less than 65%. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 Schematic diagram of the system structure for separating high-purity trimethylolbenzene and enriching mesitylene according to an embodiment of the present invention; Figure numerals: 100-pre-fractionation tower, 101-material inlet, 102-isotrimethylbenzene mixing outlet, 103-first material outlet, 104-isotrimethylbenzene mixing outlet, 105-first heating element, 106-pre-fractionation tower condensation component, 107-first reflux tank, 108-pre-fractionation tower vacuum pump, 109-pre-fractionation tower reflux pump, 110-first reflux inlet, 111-pre-fractionation tower feed preheating element, 200-isotrimethylbenzene tower, 201-isotrimethylbenzene mixing inlet, 202-isotrimethylbenzene outlet, 203-second material outlet, 204-second heating element, 205-second reflux tank, 206-isotrimethylbenzene tower reflux pump, 207-second reflux inlet, 208-isotrimethylbenzene tail gas condenser, 209-first auxiliary heating component, 210-pre-fractionation tower kettle pump , 211-trimethylbenzene tower kettle pump, 300-trimethylbenzene de-lightening tower, 301-trimethylbenzene mixed material inlet, 302-third material outlet, 303-trimethylbenzene crude material outlet, 304-third heating element, 305-trimethylbenzene de-lightening tower condensation component, 306-third reflux tank, 307-trimethylbenzene de-lightening tower vacuum pump, 308-trimethylbenzene de-lightening tower reflux pump, 400-trimethylbenzene de-heaving tower, 401-trimethylbenzene crude material inlet, 402-enriched trimethylbenzene material outlet, 403-fourth material outlet, 404-fourth heating element, 405-fourth reflux tank, 406-trimethylbenzene de-heaving tower reflux pump, 407-fourth reflux inlet, 408-trimethylbenzene de-heaving tower tail gas condenser, 409-second auxiliary heating component, 410-trimethylbenzene de-lightening tower kettle pump, 411-trimethylbenzene de-heaving tower kettle pump. DETAILED DESCRIPTION

[0039] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0040] In one aspect of the present invention, the present invention provides a system for separating high-purity trimethylolbenzene and enriching trimethylolbenzene. Figure 1 The system comprises: a pre-fractionation tower 100, a trimethylol tower 200, a homo-trimethylol removal tower 300 and a homo-trimethylol removal tower 400.

[0041] A material inlet 101 is provided on the side wall of the pre-fractionation tower 100, a mesitylene mixed material outlet 102 is provided on the side wall of the pre-fractionation tower 100 above the material inlet 101, a first material outlet 103 is provided at the top of the pre-fractionation tower 100, a mesitylene mixed material outlet 104 is provided at the bottom of the pre-fractionation tower 100, and a first heating element 105 is provided at the bottom of the pre-fractionation tower 100; The side wall of the trimethylol tower 200 is provided with a trimethylol mixing inlet 201, which is connected to the trimethylol mixing outlet 104. The top of the trimethylol tower 200 is provided with a trimethylol outlet 202, the bottom of the trimethylol tower 200 is provided with a second material outlet 203, and the bottom end of the trimethylol tower is provided with a second heating element 204; A mesitylene mixing inlet 301 is provided on the side wall of the mesitylene delightening tower 300, and a mesitylene mixing outlet 102 is connected to the mesitylene mixing inlet 301. A third material outlet 302 is provided at the top of the mesitylene delightening tower 300, a mesitylene crude material outlet 303 is provided at the bottom of the mesitylene delightening tower 300, and a third heating element 304 is provided at the bottom of the mesitylene delightening tower 300; A mesitylene crude material inlet 401 is provided on the side wall of the mesitylene deweighting tower 400, and the mesitylene crude material inlet 401 is connected to the mesitylene crude material outlet 303. A mesitylene enriched material outlet 402 is provided on the top of the mesitylene deweighting tower 400, a fourth material outlet 403 is provided at the bottom of the mesitylene deweighting tower 400, and a fourth heating element 404 is provided at the bottom of the mesitylene deweighting tower 400.

[0042] According to the system for separating high-purity trimethylolbenzene and enriching mesitylene of the above embodiment of the present invention, the C9 aromatic mixture enters the pre-fractionation tower 100 from the material inlet 101 for pre-fractionation, and the low-boiling-point components in the C9 aromatic mixture are discharged from the first material outlet 103 and sent to the tank area as the S1000# product. Trimethylolbenzene and components with higher boiling points than it are sent from the trimethylolbenzene mixed material outlet 104 to the trimethylolbenzene tower 200 for fractionation through the trimethylolbenzene mixed material inlet 201, and the obtained high-purity trimethylolbenzene is discharged from the trimethylolbenzene outlet 202. Specifically, the purity of the trimethylolbenzene is not less than 99wt%, and the obtained heavy aromatic solvent oil is discharged from the second material outlet 203. A mesitylene mixture outlet 102 is provided on the side wall of the pre-fractionation tower 100 above the material inlet 101. The inventors have found that the concentration of mesitylene distributed on the tower plate at the above-mentioned mesitylene mixture outlet 102 is high, and a mixture enriched in mesitylene can be obtained. The mixture enriched in mesitylene enters the mesitylene-removing tower 300 through the mesitylene mixture outlet 102 and the mesitylene mixture inlet 301. The components with a boiling point lower than that of mesitylene (and o-methylethylbenzene) are discharged from the third material outlet 302 and sent to the tank area as S1000# product. The remaining components are discharged from the mesitylene crude material outlet 303 through the mesitylene crude material inlet 401 to the mesitylene deheaving tower fractionation 400, and the mesitylene and o-methylethylbenzene components are discharged from the mesitylene enriched material outlet 402. Specifically, the total mass proportion of mesitylene and o-methylethylbenzene in the mixture discharged from the mesitylene enriched material outlet 402 is not less than 99%, which can be directly sent to the extractive distillation lower tower, and the obtained heavy aromatic solvent oil is discharged from the fourth material outlet 403. Thus, the system can effectively separate the C9 aromatic mixture to obtain mesitylene with a purity of not less than 99wt%, and the recovery rate of mesitylene is not less than 90%, and obtain a mesitylene and o-methylethylbenzene mixture with a total content of mesitylene and o-methylethylbenzene of 99% or more. The above-mentioned mesitylene and o-methylethylbenzene mixture can be directly used as a raw material for the extractive distillation tower, thereby improving the utilization rate of the components, reducing the investment in equipment and materials, and simplifying the operation process.

[0043] Those skilled in the art can understand that the first heating element 105, the second heating element 204, the third heating element 304, and the fourth heating element 404 are conventional devices in the field, and those skilled in the art can select them according to actual conditions, for example, a heater, a heat exchanger, etc. can be used.

[0044] According to an embodiment of the present invention, the C9 aromatic hydrocarbon mixture includes isopropylbenzene, n-propylbenzene, m-ethylethylbenzene, p-ethylethylbenzene, mesitylene, o-ethylethylbenzene, unimparted trimethylolbenzene, 1-methyl-3-n-propylbenzene, 1,3-dimethyl-5-ethylbenzene, trimethylolbenzene, 1,4-dimethyl-2-ethylbenzene, 1,3-dimethyl-4-ethylbenzene, 1,2-dimethyl-4-ethylbenzene, tetramethylolene, unimparted trimethylolene, etc., among which the content of unimparted trimethylolene is about 35%, the content of mesitylene is about 10%, and the content of trimethylolbenzene is about 7%.

[0045] According to an embodiment of the present invention, the first material outlet 103 is connected to a first reflux device, and the purity of the components separated from the first material outlet 103 is improved by the first reflux device.

[0046] According to an embodiment of the present invention, the first reflux device includes a pre-fractionation tower condensation component 106, a first reflux tank 107, a pre-fractionation tower vacuum pump 108 and a pre-fractionation tower reflux pump 109, the first material outlet 103 is connected to the first reflux tank 107 inlet, a pre-fractionation tower condensation component 106 is arranged between the first material outlet 103 and the first reflux tank 107 inlet, the pre-fractionation tower vacuum pump 108 is connected to the first reflux tank 107, the first reflux tank 107 outlet is connected to the pre-fractionation tower reflux pump 109, a part of the material is discharged through the pre-fractionation tower reflux pump 109, and the other part is refluxed to the pre-fractionation tower 100 from the first reflux inlet 110 at the upper end of the pre-fractionation tower 100. Through the above-mentioned first reflux device, a part of the material is used as the reflux of the pre-fractionation tower 100 to carry out gas-liquid mass transfer in the tower to achieve component separation, and the other part is extracted as the top product of the pre-fractionation tower 100. The top of the tower is a gas phase, and the reflux part is a condensed liquid phase, which enters from the top of the tower through a pump reflux, and forms a gas-liquid mass transfer with the gas phase at the top of the tower, thereby improving the purity of the product. It should be noted that the position of the first reflux inlet 110 is above the packing. The pre-fractionation tower condensation component 106 is a conventional component in the art, such as an air cooler.

[0047] According to an embodiment of the present invention, the partial trimethylbenzene outlet 202 is connected to a second reflux device, and the purity of the partial trimethylbenzene is further improved by the second reflux device.

[0048] According to an embodiment of the present invention, the second reflux device includes a second reflux tank 205 and a trimethylol tower reflux pump 206, the trimethylol outlet 202 is connected to the inlet of the second reflux tank 205, the outlet of the second reflux tank 205 is connected to the trimethylol tower reflux pump 206, the material is discharged through a part of the trimethylol tower reflux pump 206, and the other part is refluxed to the trimethylol tower 200 from the second reflux inlet 207 at the upper end of the trimethylol tower 200. Through the above-mentioned second reflux device, a part of the material is used as the reflux of the trimethylol tower 200 for gas-liquid mass transfer in the tower to achieve component separation, and the other part is extracted as the top product of the trimethylol tower 200. The top of the tower is a gas phase, and the reflux part is a condensed liquid phase, which enters from the top of the tower through the pump reflux, and forms a gas-liquid mass transfer with the gas phase at the top of the tower, thereby improving the purity of the product. It should be noted that the position of the second reflux inlet 207 is above the packing.

[0049] According to an embodiment of the present invention, the second reflux tank 205 is connected to the trimethylol tail gas condenser 208 .

[0050] According to an embodiment of the present invention, the trimethylolbenzene outlet 202 is connected to the first auxiliary heating component 209, and the high-temperature gas phase discharged from the trimethylolbenzene outlet 202 is used to provide heat to the pre-fractionation tower 100 through the first auxiliary heating component 209. It should be noted that the first auxiliary heating component 209 is a conventional device in the field, and those skilled in the art can select it according to actual conditions. The first auxiliary heating component 209 only needs to transfer the heat of the high-temperature gas phase discharged from the trimethylolbenzene outlet 202 to the pre-fractionation tower 100. Through this thermal coupling process, energy consumption can be significantly reduced.

[0051] According to an embodiment of the present invention, a pre-fractionation tower kettle pump 210 is provided between the partial trimethylol mixed material inlet 201 and the partial trimethylol mixed material outlet 104. The pre-fractionation tower kettle pump 210 provides power to transport materials from the pre-fractionation tower 100 to the partial trimethylol tower 200.

[0052] According to an embodiment of the present invention, the second material outlet 203 is connected to the trimethylol tower bottom pump 211 .

[0053] According to an embodiment of the present invention, the third material outlet 302 is connected to a third reflux device, so as to further improve the purity of the components separated from the third material outlet 302.

[0054] According to an embodiment of the present invention, the third reflux device includes a uniform three-delightening tower condensation component 305, a third reflux tank 306, a uniform three-delightening tower vacuum pump 307 and a uniform three-delightening tower reflux pump 308, the third material outlet 302 is connected to the third reflux tank 306 inlet, a uniform three-delightening tower condensation component 305 is provided between the third material outlet 302 and the third reflux tank 306 inlet, a uniform three-delightening tower vacuum pump 307 is connected to the third reflux tank 306, and the third reflux tank 306 outlet is connected to the uniform three-delightening tower reflux pump 308, and the material is discharged through a part of the uniform three-delightening tower reflux pump 308, and the other part is refluxed to the uniform three-delightening tower 300 from the third reflux inlet 309 at the upper end of the uniform three-delightening tower 300. Through the above-mentioned third reflux device, a part of the material is used as the reflux of the uniform three-delightening tower 300 for gas-liquid mass transfer in the tower to achieve component separation, and the other part is extracted as the top product of the uniform three-delightening tower 300. The top of the tower is gas phase, and the reflux part is the condensed liquid phase, which enters from the top of the tower through the pump reflux, and forms gas-liquid mass transfer with the gas phase at the top of the tower, thereby improving the purity of the product. It should be noted that the position of the third reflux inlet 309 is above the packing. The homogenizing three-light removal tower condensation component 305 is a conventional component in the art, such as an air cooler.

[0055] According to an embodiment of the present invention, the enriched mesitylene material outlet 402 is connected to a fourth reflux device, so that the purity of mesitylene and o-methylethylbenzene in the obtained mixture is higher through the fourth reflux device.

[0056] According to an embodiment of the present invention, the fourth reflux device includes a fourth reflux tank 405 and a uniform three-weight removal tower reflux pump 406, and the enriched three-toluene material outlet 402 is connected to the fourth reflux tank 405 entrance, and the fourth reflux tank 405 outlet is connected to the uniform three-weight removal tower reflux pump 406, and the material is discharged through a part of the uniform three-weight removal tower reflux pump 406, and the other part is refluxed to the uniform three-weight removal tower 400 from the fourth reflux inlet 407 at the upper end of the uniform three-weight removal tower 400. Through the above-mentioned fourth reflux device, a part of the material is used as the reflux of the uniform three-weight removal tower 400 for gas-liquid mass transfer in the tower to achieve component separation, and the other part is extracted as the top product of the uniform three-weight removal tower 400. The top of the tower is a gas phase, and the reflux part is a condensed liquid phase, which enters from the top of the tower through the pump reflux, and forms a gas-liquid mass transfer with the top gas phase, thereby improving the purity of the product. It should be noted that the fourth reflux inlet 407 is arranged above the filler.

[0057] According to an embodiment of the present invention, the fourth reflux tank 405 is connected to the tail gas condenser 408 of the triple deweighting tower.

[0058] According to an embodiment of the present invention, the enriched mesitylene material outlet 402 is connected to the second auxiliary heating component 409, and the high-temperature gas phase discharged from the enriched mesitylene material outlet 402 is used to provide heat to the mesitylene-removing tower 300 through the second auxiliary heating component 409. It should be noted that the second auxiliary heating component 409 is a conventional device in the field, and those skilled in the art can select it according to actual conditions. The second auxiliary heating component 409 only needs to transfer the heat of the high-temperature gas phase discharged from the enriched mesitylene material outlet 402 to the mesitylene-removing tower 300. Through this thermal coupling process, energy consumption can be significantly reduced.

[0059] According to an embodiment of the present invention, a mesitylene crude material outlet 303 and a mesitylene crude material inlet 401 are provided with a mesitylene delightening tower kettle pump 410. The mesitylene delightening tower kettle pump 410 provides power to transport materials from the mesitylene delightening tower 300 to the mesitylene deheaving tower 400.

[0060] According to an embodiment of the present invention, the fourth material outlet 403 is connected to the kettle pump 411 of the homogenizing and deweighting tower.

[0061] According to an embodiment of the present invention, the material inlet 101 is connected to the pre-fractionation tower feed preheating element 111. The pre-fractionation tower feed preheating element 111 preliminarily preheats the C9 aromatic hydrocarbon mixture, thereby improving the subsequent process efficiency.

[0062] According to an embodiment of the present invention, the pre-fractionation tower 100, the trimethylol tower 200, the homo-trimethylol removal tower 300, and the homo-trimethylol removal tower 400 each independently use 8 sections of fillers. The inventors have found that the use of 8 sections of fillers can achieve effective separation of the components of the distillation tower. Furthermore, the filler uses a hyperbolic high-efficiency structured packing, thereby improving the fractionation effect.

[0063] According to an embodiment of the present invention, the material inlet 101 is arranged at the lower part of the second stage packing and the upper part of the third stage packing. The inventors found that if the material inlet 101 is too high, the raw material may be vaporized too early, causing the light component to mix with the heavy component, affecting the separation effect; while if the material inlet 101 is too low, the raw material may be vaporized too late, increasing the heat load at the bottom of the tower, which is not conducive to energy saving and separation.

[0064] According to an embodiment of the present invention, the mesitylene mixed material outlet 102 is arranged at the lower part of the first stage filler and the upper part of the second stage filler. The inventors have found that the mesitylene mixed material outlet 102 is arranged at the lower part of the first stage filler and the upper part of the second stage filler, so that a higher concentration of mesitylene components can be produced, which can not only improve the yield of mesitylene, but also separate more light components with lower boiling points than mesitylene.

[0065] According to the embodiment of the present invention, the mesitylene mixed material inlet 301 is arranged at the lower part of the second stage filler and the upper part of the third stage filler, so as to improve the separation effect and save energy consumption.

[0066] According to an embodiment of the present invention, the mesitylene crude material inlet 401 is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing. The selection of the position of the mesitylene crude material inlet 401 is determined by optimizing the production parameters. Reasonable selection of the feeding position can significantly improve the separation efficiency, ensure the product quality, and also help to save energy and reduce costs.

[0067] According to an embodiment of the present invention, the partial trimethylbenzene mixing inlet 201 is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing. The selection of the position of the partial trimethylbenzene mixing inlet 201 is determined by optimizing the production parameters. Reasonable selection of the feeding position can significantly improve the separation efficiency, ensure the product quality, and also help to save energy and reduce costs.

[0068] In another aspect of the present invention, the present invention proposes a process for separating high-purity trimethylolbenzene and enriching mesitylene using the above system. According to an embodiment of the present invention, the process comprises: The C9 aromatic hydrocarbon mixture enters the pre-fractionation tower 100 from the material inlet, and the trimethylol mixed material enters the trimethylol tower fractionation 200 from the trimethylol mixed material outlet 104 of the pre-fractionation tower 100 through the trimethylol mixed material inlet 201 to obtain trimethylol; The material containing mesitylene enters the mesitylene-delightening tower fractionation 300 from the mesitylene mixed material outlet 102 of the pre-fractionation tower 100 through the mesitylene mixed material inlet 301. The mesitylene crude material obtained by the mesitylene-delightening tower 300 enters the mesitylene-deheaving tower fractionation 400 from the mesitylene crude material outlet 303 through the mesitylene crude material inlet 401 to obtain a mixture of mesitylene and o-methylethylbenzene.

[0069] Thus, the method can be used to effectively separate the C9 aromatic hydrocarbon mixture, and obtain a partial trimethylolus with a purity of not less than 99wt% and a mixture of mesitylene and o-methylethylbenzene with a total content of mesitylene and o-methylethylbenzene of not less than 99%, and the above-mentioned mixture of mesitylene and o-methylethylbenzene can be directly used as a raw material for an extractive distillation tower. Specifically, the purity of the obtained partial trimethylolus is not less than 99wt%; the mass proportion of the total amount of mesitylene and o-methylethylbenzene in the obtained mixture of mesitylene and o-methylethylbenzene is not less than 99wt%; the mass proportion of mesitylene in the obtained mixture of mesitylene and o-methylethylbenzene is not less than 65%.

[0070] According to an embodiment of the present invention, the pressure of the pre-fractionation tower 100 is 8KPa~30KPa, and the temperature of the top of the pre-fractionation tower 100 is 82℃~119℃. The inventors found that the pre-fractionation tower 100 adopts the above-mentioned negative pressure operation to increase the relative volatility of the components, which is more conducive to separation. Secondly, the operating temperature is reduced, more steam is saved, and energy consumption is saved. The pre-fractionation tower 100 adopts a negative pressure tower bottom temperature and the trimethylolbenzene tower 200 adopts a positive pressure tower top temperature. Therefore, the top heat material of the trimethylolbenzene tower 200 can be used to heat the pre-fractionation tower bottom, and a thermal coupling process can be established to save energy.

[0071] According to an embodiment of the present invention, the pressure of the trimethylolbenzene tower 200 is 120KPa~200KPa, and the temperature of the top of the trimethylolbenzene tower 200 is 176°C~199°C. The inventors found that the trimethylolbenzene tower 200 adopts positive pressure operation and has a relatively high temperature, and can establish a thermal coupling process with the pre-fractionation tower 100 to save energy, and at the above temperature and pressure, the separation effect of the components is good.

[0072] According to an embodiment of the present invention, the pressure of the homogeneous three-delightening tower 300 is 15KPa~30KPa, and the temperature of the top of the homogeneous three-delightening tower is 99℃~120℃. The inventors found that the homogeneous three-delightening tower 300 adopts negative pressure operation to increase the relative volatility of the components, which is more conducive to separation, and secondly reduces the operating temperature, saves more steam, and saves energy. The homogeneous three-delightening tower 300 adopts a negative pressure tower kettle temperature is low, and the homogeneous three-deweighting tower 400 adopts a positive pressure tower top temperature. Therefore, the hot material at the top of the homogeneous three-deweighting tower 400 can be used to heat the tower kettle of the homogeneous three-delightening tower 300, and a thermal coupling process is established to save energy.

[0073] According to an embodiment of the present invention, the pressure of the homogenous three-deweighting tower 400 is 120KPa~200KPa, and the temperature of the top of the homogenous three-deweighting tower is 171°C~195°C. The inventors found that the homogenous three-deweighting tower 400 adopts positive pressure operation and has a relatively high temperature, and can establish a thermal coupling process with the homogenous three-deweighting tower 300 to save energy, and at the above temperature and pressure, the separation effect of the components is good.

[0074] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0075] Example 1

[0076] After the C9 aromatic raw material is heated to 113°C by the preheater of the pre-fractionation tower, it enters the lower part of the second packing of the pre-fractionation tower. The pre-fractionation tower is operated at 15KPa, and the top temperature is controlled at 101°C. The top of the tower is connected to the pre-fractionation tower vacuum pump. The top gas of the pre-fractionation tower is condensed to 65°C by the top air cooler and then enters the pre-fractionation tower reflux tank (the first reflux tank). One part is used as reflux, and the other part is produced as 1000# aromatic product. The material at the bottom of the pre-fractionation tower enters the lower part of the fourth section packing of the trimethylol tower through the kettle pump of the pre-fractionation tower. The trimethylol tower is operated at 120KPa, and the top temperature is controlled at 176°C. The top gas phase of the trimethylol tower is used as the heat source of the first auxiliary heating component to achieve thermal coupling. The insufficient heat source uses low-pressure steam to heat the first heating element. The top gas phase of the trimethylol tower is self-pressurized to the trimethylol tower reflux tank (the second reflux tank) after heat exchange. One part is used as reflux, and the other part is produced as a high-purity trimethylol product. The tail gas of the trimethylol tower reflux tank is condensed by the trimethylol tail gas condenser and discharged to the tail gas system. The material at the bottom of the trimethylol tower is produced by the kettle pump of the trimethylol tower to produce heavy aromatic solvent oil.

[0077] The enriched mesitylene mixture is produced from the side line of the pre-fractionation tower and enters the mesitylene de-lightening tower. The mesitylene de-lightening tower is operated at 30KPa, and the top temperature is controlled at 120℃. The top of the tower is connected to the mesitylene de-lightening tower vacuum pump. The fraction with a boiling point lower than that of mesitylene is separated from the top of the mesitylene de-lightening tower, and is condensed to 65℃ by the top air cooler (mesitylene de-lightening tower condensation component) and then enters the mesitylene de-lightening tower reflux tank (the third reflux tank). One part is used as reflux, and the other part is produced as 1000# aromatics product. The bottom material of the homogenous three-deionizing tower enters the lower part of the fourth section packing of the homogenous three-deionizing tower through the kettle pump of the homogenous three-deionizing tower. The homogenous three-deionizing tower is operated at 120KPa, and the top temperature is controlled at 172℃. The top gas phase of the homogenous three-deionizing tower is used as the heat source of the second auxiliary heating component to achieve thermal coupling. The insufficient heat source uses low-pressure steam to heat the third heating element. The top gas phase of the homogenous three-deionizing tower is self-pressurized to the reflux tank (the fourth reflux tank) of the homogenous three-deionizing tower after heat exchange. One part is used as reflux, and the other part is extracted as a mixture of mesitylene and o-methylethylbenzene with a content of more than 99%, which is directly used as a raw material for the extraction of mesitylene distillation tower. The tail gas of the reflux tank of the homogenous three-deionizing tower is condensed by the tail gas condenser of the homogenous three-deionizing tower and discharged to the tail gas system. The bottom material of the homogenous three-deionizing tower is extracted by the kettle pump of the homogenous three-deionizing tower. The fraction with a boiling point higher than that of mesitylene and o-methylethylbenzene is sent to the partial trimethylbenzene tower for reuse or directly used as 1000# aromatic solvent.

[0078] The purity of the obtained unisex trimethylol product reaches over 99%, and the total mass of the unisex trimethylol and o-methylethylbenzene in the obtained enriched mixture of trimethylol and o-methylethylbenzene accounts for over 99% of the total mass of the mixture, and the product can be directly used as a raw material for an extractive distillation tower. The mass proportion of the unisex trimethylol in the enriched mixture of trimethylol and o-methylethylbenzene is over 65%, and the yield of unisex trimethylol is over 90%.

[0079] Example 2

[0080] After the C9 aromatic raw material is heated to 113°C by the preheater of the pre-fractionation tower, it enters the lower part of the second packing section of the pre-fractionation tower. The pre-fractionation tower is operated at 30KPa, and the top temperature is controlled at 119°C. The top of the tower is connected to the pre-fractionation tower vacuum pump. The top gas of the pre-fractionation tower is condensed to 65°C by the top air cooler and then enters the pre-fractionation tower reflux tank (the first reflux tank). One part is used as reflux, and the other part is produced as 1000# aromatic product. The material at the bottom of the pre-fractionation tower enters the lower part of the fourth section packing of the trimethylol tower through the kettle pump of the pre-fractionation tower. The trimethylol tower is operated at 160KPa, and the top temperature is controlled at 188°C. The top gas phase of the trimethylol tower is used as the heat source of the first auxiliary heating component to achieve thermal coupling. The insufficient heat source uses low-pressure steam to heat the first heating element. The top gas phase of the trimethylol tower is self-pressurized to the trimethylol tower reflux tank (the second reflux tank) after heat exchange. One part is used as reflux, and the other part is produced as a high-purity trimethylol product. The tail gas of the trimethylol tower reflux tank is condensed by the trimethylol tail gas condenser and discharged to the tail gas system. The material at the bottom of the trimethylol tower is produced into heavy aromatic solvent oil through the kettle pump of the trimethylol tower.

[0081] The enriched mesitylene is extracted from the side line of the pre-fractionation tower and enters the mesitylene-delightening tower. The mesitylene-delightening tower is operated at 15KPa, and the top temperature is controlled at 99℃. The top of the tower is connected to the vacuum pump of the mesitylene-delightening tower. The fraction with a boiling point lower than that of mesitylene is separated from the top of the mesitylene-delightening tower, and is condensed to 65℃ by the top air cooler (mesitylene-delightening tower condensation component) and then enters the reflux tank of the mesitylene-delightening tower (the third reflux tank). One part is used as reflux, and the other part is extracted as 1000# aromatics product. The bottom material of the homogenous three-deionizing tower enters the lower part of the fourth section packing of the homogenous three-deionizing tower through the kettle pump of the homogenous three-deionizing tower. The homogenous three-deionizing tower is operated at 150KPa, and the top temperature is controlled at 181℃. The top gas phase of the homogenous three-deionizing tower is used as the heat source of the second auxiliary heating component to achieve thermal coupling. The insufficient heat source uses low-pressure steam to heat the third heating element. The top gas phase of the homogenous three-deionizing tower is self-pressurized to the reflux tank of the homogenous three-deionizing tower (the fourth reflux tank) after heat exchange. One part is used as reflux, and the other part is extracted as a mixture of mesitylene and o-methylethylbenzene with a content of more than 99%, which is directly used as raw material for the extraction of mesitylene distillation tower. The tail gas of the reflux tank of the homogenous three-deionizing tower is condensed by the tail gas condenser of the homogenous three-deionizing tower and discharged to the tail gas system. The bottom material of the homogenous three-deionizing tower is extracted by the kettle pump of the homogenous three-deionizing tower. The fraction with a boiling point higher than that of mesitylene and o-methylethylbenzene is sent to the partial trimethylbenzene tower for reuse or directly used as 1000# aromatic solvent.

[0082] The purity of the obtained unisex trimethylol product reaches over 99%, and the total mass of the unisex trimethylol and o-methylethylbenzene in the obtained enriched mixture of trimethylol and o-methylethylbenzene accounts for over 99% of the total mass of the mixture, and the product can be directly used as a raw material for an extractive distillation tower. The mass proportion of the unisex trimethylol in the enriched mixture of trimethylol and o-methylethylbenzene is over 65%, and the yield of unisex trimethylol is over 90%.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for separating high-purity trimethylolbenzene and enriching mesitylene, characterized in that: include: Pre-fractionation tower, trimethylol tower, homo-trimethylbenzene light removal tower and homo-trimethylolene heavy removal tower, The side wall of the pre-fractionation tower is provided with a material inlet, the side wall of the pre-fractionation tower above the material inlet is provided with a mesitylene mixed material outlet, the top of the pre-fractionation tower is provided with a first material outlet, the bottom of the pre-fractionation tower is provided with a partial trimethylol mixed material outlet, and the bottom of the pre-fractionation tower is provided with a first heating element; The side wall of the partial trimethylol tower is provided with a partial trimethylol mixing inlet, the partial trimethylol mixing inlet is connected to the partial trimethylol mixing outlet of the pre-fractionation tower, the top of the partial trimethylol tower is provided with a partial trimethylol outlet, the bottom of the partial trimethylol tower is provided with a second material outlet, and the bottom end of the partial trimethylol tower is provided with a second heating element; The side wall of the mesitylene delightening tower is provided with a mesitylene mixing inlet, the mesitylene mixing inlet is connected to the mesitylene mixing outlet of the pre-fractionation tower, the top of the mesitylene delightening tower is provided with a third material outlet, the bottom of the mesitylene delightening tower is provided with a mesitylene crude material outlet, and the bottom end of the mesitylene delightening tower is provided with a third heating element; The side wall of the isocyanate deweighting tower is provided with an inlet for crude isocyanate material, the inlet for crude isocyanate material is connected with the outlet for crude isocyanate material, the top of the isocyanate deweighting tower is provided with an outlet for enriched isocyanate material, the bottom of the isocyanate deweighting tower is provided with a fourth material outlet, and the bottom end of the isocyanate deweighting tower is provided with a fourth heating element.

2. The system according to claim 1, characterized in that The first material outlet is connected to a first reflux device; And / or, the trimethylol outlet is connected to a second reflux device; And / or, the third material outlet is connected to a third reflux device; And / or, the outlet of the enriched mesitylene material is connected to a fourth reflux device.

3. The system according to claim 2, characterized in that The first reflux device comprises a pre-fractionation tower condensation component, a first reflux tank, a pre-fractionation tower vacuum pump and a pre-fractionation tower reflux pump, the first material outlet is connected to the first reflux tank inlet, the pre-fractionation tower condensation component is arranged between the first material outlet and the first reflux tank inlet, the pre-fractionation tower vacuum pump is connected to the first reflux tank, the first reflux tank outlet is connected to the pre-fractionation tower reflux pump, a part of the material is discharged through the pre-fractionation tower reflux pump, and the other part is refluxed to the pre-fractionation tower from the first reflux inlet at the upper end of the pre-fractionation tower; And / or, the second reflux device comprises a second reflux tank and a trimethylolbenzene tower reflux pump, the trimethylolbenzene outlet is connected to the second reflux tank inlet, the second reflux tank outlet is connected to the trimethylolbenzene tower reflux pump, a part of the material is discharged through the trimethylolbenzene tower reflux pump, and the other part is refluxed to the trimethylolbenzene tower from the second reflux inlet at the upper end of the trimethylolbenzene tower; And / or, the third reflux device comprises a homogeneous three-delightening tower condensation component, a third reflux tank, a homogeneous three-delightening tower vacuum pump and a homogeneous three-delightening tower reflux pump, the third material outlet is connected to the third reflux tank inlet, the homogeneous three-delightening tower condensation component is arranged between the third material outlet and the third reflux tank inlet, the homogeneous three-delightening tower vacuum pump is connected to the third reflux tank, the third reflux tank outlet is connected to the homogeneous three-delightening tower reflux pump, a part of the material is discharged through the homogeneous three-delightening tower reflux pump, and the other part is refluxed to the homogeneous three-delightening tower from the third reflux inlet at the upper end of the homogeneous three-delightening tower; And / or, the fourth reflux device includes a fourth reflux tank and a mesitylene detoxification tower reflux pump, the enriched mesitylene material outlet is connected to the fourth reflux tank inlet, the fourth reflux tank outlet is connected to the mesitylene detoxification tower reflux pump, a part of the material is discharged through the mesitylene detoxification tower reflux pump, and the other part is refluxed to the mesitylene detoxification tower from the fourth reflux inlet at the upper end of the mesitylene detoxification tower.

4. The system according to any one of claims 1 to 3, characterized in that: The partial trimethylolbenzene outlet is connected to a first auxiliary heating component, and the high-temperature gas phase discharged from the partial trimethylolbenzene outlet is used to provide heat to the pre-fractionation tower through the first auxiliary heating component; And / or, the outlet of the enriched mesitylene material is connected to a second auxiliary heating component, and the high-temperature gas phase discharged from the outlet of the enriched mesitylene material is used to provide heat to the mesitylene-removal tower through the second auxiliary heating component.

5. The system according to any one of claims 1 to 3, characterized in that: The pre-fractionation tower, the trimelene tower, the homo-trimethylbenzene removal tower, and the homo-trimethylbenzene removal tower each independently use 8 sections of fillers.

6. The system according to claim 5, characterized in that The material inlet of the pre-fractionation tower is arranged at the lower part of the second section packing and the upper part of the third section packing; And / or, the mesitylene mixed material outlet of the pre-fractionation tower is arranged at the lower part of the first stage packing and the upper part of the second stage packing; And / or, the partial trimethylol mixed material inlet of the partial trimethylol tower is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing; And / or, the mesitylene mixed material inlet of the mesitylene removal tower is arranged at the lower part of the second stage packing and the upper part of the third stage packing; And / or, the mesitylene crude material inlet of the mesitylene deweighting tower is arranged at the lower part of the fourth section packing and the upper part of the fifth section packing.

7. The system according to any one of claims 1 to 3, characterized in that: A pre-fractionation tower kettle pump is provided between the partial trimethylol mixed material inlet and the partial trimethylol mixed material outlet; And / or, the second material outlet is connected to the kettle pump of the trimethylol tower; And / or, a tower kettle pump of a mesitylene removal tower is provided between the mesitylene crude material outlet and the mesitylene crude material inlet; And / or, the fourth material outlet is connected to the kettle pump of the triple deweighting tower; And / or, the material inlet is connected to a pre-fractionation tower feed preheating component.

8. A process for separating high-purity trimethylolbenzene and enriching mesitylene using the system described in any one of claims 1 to 7, characterized in that: include: The C9 aromatic hydrocarbon mixture enters the pre-fractionation tower from the material inlet, and the trimethylol mixed material enters the trimethylol tower from the trimethylol mixed material outlet of the pre-fractionation tower through the trimethylol mixed material inlet for fractionation to obtain trimethylol; The material containing mesitylene enters a mesitylene-delightening tower from the mesitylene mixed material outlet of the pre-fractionation tower through the mesitylene mixed material inlet for distillation. The mesitylene crude material obtained by distillation in the mesitylene-delightening tower enters a mesitylene-deheavy tower from the mesitylene crude material outlet through the mesitylene crude material inlet for distillation to obtain a mixture of mesitylene and o-methylethylbenzene.

9. The process according to claim 8, characterized in that The pressure of the pre-fractionation tower is 8KPa~30KPa, and the temperature of the top of the pre-fractionation tower is 82°C~119°C; And / or, the pressure of the trimethylolbenzene tower is 120 KPa-200 KPa, and the temperature of the top of the trimethylolbenzene tower is 176° C.-199° C.; And / or, the pressure of the homogenizing and degassing tower is 15KPa-30KPa, and the temperature of the top of the homogenizing and degassing tower is 99°C-120°C; And / or, the pressure of the homogenous triple deweighting tower is 120KPa~200KPa, and the temperature of the top of the homogenous triple deweighting tower is 171℃~195℃.

10. The process according to claim 8 or 9, characterized in that The purity of the obtained trimethylol is not less than 99wt%; and / or, the mass proportion of the total amount of mesitylene and o-methylethylbenzene in the obtained mixture of mesitylene and o-methylethylbenzene is not less than 99wt%; And / or, the mass proportion of mesitylene in the obtained mixture of mesitylene and o-methylethylbenzene is not less than 65%.

Images