Organic silicon complete pressure-thermal coupling rectification device and rectification method

Abstract

The application discloses a kind of organic silicon complete pressure thermal coupling rectification device and rectification method.The device includes high-tower, low-tower, high-pressure binary tower and low-pressure binary tower, and the low-tower and low-pressure binary tower are respectively provided with tower kettle coupling reboiler.The top of the high-tower is connected with the low-pressure binary tower kettle coupling reboiler, and the top gas phase flow of the high-tower provides heat source for the low-pressure binary tower kettle coupling reboiler.The top of the high-pressure binary tower is connected with the low-tower kettle coupling reboiler, and the top gas phase flow of the high-pressure binary tower provides heat source for the low-tower kettle coupling reboiler.By adjusting the feed quantity of high and low-pressure binary tower, the complete coupling of high, low-pressure binary tower heat is realized, the defects of partial coupling between tower and the fact that complete coupling is not realized in the prior art are solved, the energy consumption is reduced, and the additional equipment investment for stable operation of the system is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of silicone rectification, and relates to a silicone rectification process, in particular to a complete variable pressure heat coupling rectification device and method for silicone. BACKGROUND

[0002] At a high reaction temperature, a halogenated hydrocarbon and silicon powder are reacted by a catalyst to generate methyl chlorosilane crude monomer, which mainly contains trimethyl monochlorosilane (Me3), monomethyl trichlorosilane (Me1) and dimethyl dichlorosilane (Me2), as well as high-boiling substances with a higher boiling point than dimethyl dichlorosilane (Me2) and low-boiling substances with a lower boiling point than trimethyl monochlorosilane (Me3).

[0003] The separation of methyl chlorosilane crude monomer will go through the treatment of high-boiling substance removal, low-boiling substance removal and binary column, that is, the methyl chlorosilane crude monomer enters the high-boiling substance removal column, and the high-boiling substances including part of dimethyl dichlorosilane (Me2) and high-boiling substances with a higher boiling point than dimethyl dichlorosilane (Me2) are removed at the column bottom, the top product enters the low-boiling substance removal column, the top product mainly contains trimethyl monochlorosilane (Me3) and low-boiling substances with a lower boiling point than trimethyl monochlorosilane (Me3), and the column bottom product mainly contains a mixture of monomethyl trichlorosilane (Me1) and dimethyl dichlorosilane (Me2) and enters the binary column. The top product of the binary column is qualified monomethyl trichlorosilane (Me1) product, and the column bottom product is dimethyl dichlorosilane (Me2) product. The remaining low-boiling substances and high-boiling substances enter subsequent rectification columns for separation. As the main process for producing dimethyl dichlorosilane (Me2), the reasonable optimization of the high-boiling substance removal column, the low-boiling substance removal column and the binary column is particularly important.

[0004] The high-boiling substance removal column, the low-boiling substance removal column and the binary column in industry generally adopt a conventional series mode, that is, the methyl chlorosilane crude monomer enters the high-boiling substance removal column, the heavy components including part of dimethyl dichlorosilane (Me2) and high-boiling substances with a higher boiling point than dimethyl dichlorosilane (Me2) are removed at the column bottom, and the light components including dimethyl dichlorosilane (Me2) and low-boiling substances with a lower boiling point than dimethyl dichlorosilane (Me2) enter the low-boiling substance removal column. The top product of the low-boiling substance removal column mainly contains trimethyl monochlorosilane (Me3) and low-boiling substances with a lower boiling point than trimethyl monochlorosilane (Me3), and the column bottom product mainly contains a mixture of dimethyl dichlorosilane (Me2) and monomethyl trichlorosilane (Me1) and enters the binary column. The top product of the binary column is qualified monomethyl trichlorosilane (Me1) product, and the column bottom product is dimethyl dichlorosilane (Me2) product. The high-boiling substance removal column, the low-boiling substance removal column and the binary column can be composed of a single column or multiple columns in series according to the requirements of users. Since the high-boiling substance removal column, the low-boiling substance removal column and the binary column are located at the front end of the rectification process, the feed amount is large, and the separation precision requirement is also high. The energy consumption is equivalent to about 90% of the binary column, so the amount of circulating water and steam is large, and the energy consumption is high. How to reduce the energy consumption of the whole system becomes a technical problem to be solved.

[0005] Chinese patent application No. 201010132940.8 proposes a concept of using the de-high column as the heat source of the whole rectification system, but this concept increases the operating temperature and pressure of the de-high column, which greatly increases the energy consumption of the de-high column and also greatly affects the energy consumption of the whole system; meanwhile, the steam of the de-high column is supplied to the reboilers at the bottoms of the de-low column, the light column, the hydrogen-containing column, the azeotrope column, the trimethyl column, the monomethyl column and the dimethyl column through the distribution header, and the insufficient heat is provided by the second reboiler using steam as the heat source. Since the steam is distributed too many times and the process is too complex, it brings great risk to the stable operation of the subsequent columns, and therefore it is not practical for the whole system. Chinese patent application No. 201010209928.2 proposes a parallel double-effect rectification method for separating Me1 and Me2, but it does not solve the problem of high energy consumption in the de-high and de-low processes of the methyl chlorosilane crude monomer. Chinese patent application No. 201210032092.2 proposes a new process for separating the methyl chlorosilane crude monomer, but it still uses the conventional series mode and does not solve the problem of energy consumption of the de-high column and the de-low column.

[0006] In addition, the prior art usually needs an additional condenser in the coupled column to condense the excess steam, or introduces the excess steam into the reboiler of the next column as the heat source, and then the next column needs another reboiler using steam as the heat source to make up for the insufficient heat, which increases the equipment investment and also increases the risk of affecting the stable operation of the system due to the complex process.

[0007] Therefore, how to reduce the energy consumption of the system and maintain the stable operation of the system without increasing the equipment investment has become a technical problem to be solved in the field of organosilicon. SUMMARY

[0008] The present application provides an organosilicon variable-pressure complete heat-coupled rectification device, which comprises a de-high column, a de-low column, a high-pressure binary column and a low-pressure binary column,

[0009] The de-low column and the low-pressure binary column are respectively provided with a column-coupled reboiler;

[0010] The top of the de-high column is connected with the column-coupled reboiler of the low-pressure binary column, and the gaseous phase stream at the top of the de-high column provides the heat source for the column-coupled reboiler of the low-pressure binary column;

[0011] The top of the high-pressure binary column is connected with the column-coupled reboiler of the de-low column, and the gaseous phase stream at the top of the high-pressure binary column provides the heat source for the column-coupled reboiler of the de-low column.

[0012] According to the embodiment of the present application, the gaseous phase material from the top of the de-high column enters the shell side inlet of the low-pressure binary column bottom coupled reboiler, and the shell side outlet of the low-pressure binary column bottom coupled reboiler is connected with the upper end of the de-high column, forming a loop. Preferably, a de-high column reflux tank can be arranged on the connecting line between the shell side outlet of the low-pressure binary column bottom coupled reboiler and the upper end of the de-high column, for storing the de-high column overhead components after heat exchange from the shell side outlet of the low-pressure binary column bottom coupled reboiler. Preferably, the shell side outlet of the low-pressure binary column bottom coupled reboiler is connected with the de-high column reflux tank, and a de-high component removal branch can be arranged on the connecting line between the de-high column reflux tank and the upper end of the de-high column, and the de-high component removal branch is connected with the de-low column.

[0013] According to the embodiment of the present application, the bottom of the de-high column is provided with a de-high column bottom reboiler, one end of which is connected with the bottom of the de-high column, and the other end is connected with the bottom of the de-high column.

[0014] According to the embodiment of the present application, the bottom of the de-high column can also be provided with a de-high column heavy component removal pipeline for removing heavy components.

[0015] According to the embodiment of the present application, the top of the de-low column is provided with a de-low column overhead condenser for condensing the de-low column overhead removal material. Preferably, one end of the de-low column overhead condenser is connected with the top of the de-low column, and the other end is connected with the upper end of the de-low column. Preferably, a de-low column reflux tank can be arranged on the connecting line between the de-low column overhead condenser and the upper end of the de-low column, and the de-low column reflux tank is arranged downstream of the de-low column overhead condenser. Preferably, a condensate outlet can be further included on the connecting line between the de-low column reflux tank and the upper end of the de-low column, and the condensate outlet is connected with an external pipeline.

[0016] According to the embodiment of the present application, the de-low column bottom coupled reboiler includes a bottom liquid outlet and a bottom liquid inlet, a shell side outlet and a shell side inlet. The bottom liquid inlet of the de-low column bottom coupled reboiler is connected with the bottom of the de-low column, and the bottom liquid outlet of the de-low column bottom coupled reboiler is connected with the bottom of the de-low column.

[0017] The shell inlet of the low-removing column bottom coupled reboiler is connected with the top of the high-pressure binary column, and the shell outlet of the low-removing column bottom coupled reboiler is connected with the upper end of the high-pressure binary column, thereby forming a loop. Preferably, a high-pressure binary column reflux tank can be arranged on the connection line between the shell outlet of the low-removing column bottom coupled reboiler and the upper end of the high-pressure binary column, for storing the high-pressure binary column top components after heat exchange. Preferably, the shell outlet of the low-removing column bottom coupled reboiler is connected with the high-pressure binary column reflux tank, and a material extraction branch can also be arranged on the connection line between the reflux tank and the upper end of the high-pressure binary column, for extracting the high-pressure binary column top components after heat exchange.

[0018] According to the embodiment of the present application, the bottom of the low-removing column can also be provided with a low-removing column bottom material extraction pipeline, which is connected with the high-pressure binary column and the low-pressure binary column respectively.

[0019] According to the embodiment of the present application, the high-pressure binary column and the low-pressure binary column are connected in parallel.

[0020] According to the embodiment of the present application, the bottom of the high-pressure binary column is provided with a high-pressure binary column bottom reboiler, one end of which is connected with the bottom of the high-pressure binary column, and the other end of which is connected with the bottom of the high-pressure binary column.

[0021] According to the embodiment of the present application, the bottom of the high-pressure binary column can also be provided with a high-pressure binary column bottom material extraction pipeline, for extracting the bottom material.

[0022] According to the embodiment of the present application, the top of the low-pressure binary column is provided with a low-pressure binary column top condenser, for condensing the low-pressure binary column top extraction. One end of the low-pressure binary column top condenser is connected with the top of the low-pressure binary column, and the other end of the low-pressure binary column top condenser is connected with the upper end of the low-pressure binary column. Preferably, a low-pressure binary column reflux tank can also be arranged on the connection line between the low-pressure binary column top condenser and the upper end of the low-pressure binary column, and the low-pressure binary column reflux tank is arranged downstream of the low-pressure binary column top condenser. Preferably, the low-pressure binary column reflux tank can also include a condensate extraction outlet on the connection line between the low-pressure binary column reflux tank and the upper end of the low-pressure binary column, and the condensate extraction outlet is connected with an external pipeline.

[0023] According to the embodiment of the present application, the low-pressure binary column bottom coupled reboiler includes a bottom liquid inlet and a bottom liquid outlet, the bottom liquid inlet of the low-pressure binary column bottom coupled reboiler is connected with the bottom of the low-pressure binary column, and the bottom liquid outlet of the low-pressure binary column bottom coupled reboiler is connected with the bottom of the low-pressure binary column.

[0024] According to the embodiment of the present application, the low-pressure binary column can also be provided with a column bottom material tapping line for tapping the column bottom material of the low-pressure binary column.

[0025] According to the embodiment of the present application, the de-high column is selected from a pressurized or atmospheric distillation column.

[0026] According to the embodiment of the present application, the de-low column is selected from an atmospheric or negative pressure distillation column.

[0027] According to the embodiment of the present application, the high-pressure binary column is selected from a pressurized or atmospheric distillation column.

[0028] According to the embodiment of the present application, the low-pressure binary column is selected from an atmospheric or negative pressure distillation column.

[0029] According to the embodiment of the present application, the de-high column, de-low column, high-pressure binary column and low-pressure binary column are plate columns and / or packed columns.

[0030] According to the embodiment of the present application, the lower part of the de-high column is preferably a plate column to prevent plugging.

[0031] According to the embodiment of the present application, the packed column has a lower operating pressure drop, and therefore the upper part of the de-high column is preferably a packed column. Preferably, the de-low column is a packed column.

[0032] In the device of the present application, the complete coupling of the de-high column, de-low column and binary columns enables the de-high column and high-pressure binary column to be provided only with reboilers and not with condensers, and only a set of coupled reboilers of the low-pressure de-low column and low-pressure binary column is needed to enable stable operation, without the need for other condensers and reboilers to provide additional cold and heat sources.

[0033] Optionally, the device can also include a backup cold source and / or a backup heat source. For example, the backup cold source can be a condenser, and the backup heat source can be a reboiler. Those skilled in the art can understand that, according to the operation of each column, a backup cold source can be provided at the top of the column, and a backup heat source can be provided at the column bottom, and the backup cold source and backup heat source are respectively connected with circulating water or steam, or can be connected with other process streams for heat exchange and heat utilization.

[0034] According to the embodiment of the present application, the complete pressure swing thermal coupling distillation device for organosilicon includes a de-high column, a de-low column, a high-pressure binary column and a low-pressure binary column,

[0035] The de-low column is provided with a de-low column top condenser at the top thereof, and the low-pressure binary column is provided with a low-pressure binary column top condenser at the top thereof;

[0036] The de-high column and high-pressure binary column are respectively provided with column bottom reboilers, and the de-low column and low-pressure binary column are respectively provided with coupled reboilers.

[0037] The shell side inlet of the overhead of the high-pressure binary column is connected with the reboiler of the low-pressure binary column, and the shell side outlet of the reboiler of the low-pressure binary column is connected with the upper end of the high-pressure binary column, forming a loop; the gas phase flow at the top of the high-pressure binary column provides heat source for the low-pressure binary column, and is cooled at the same time.

[0038] The shell side inlet of the overhead of the high-pressure binary column is connected with the reboiler of the low-pressure binary column, and the shell side outlet of the reboiler of the low-pressure binary column is connected with the upper end of the high-pressure binary column, forming a loop; the gas phase flow at the top of the high-pressure binary column provides heat source for the low-pressure binary column, and is cooled at the same time.

[0039] The application also provides a complete pressure swing heat coupling distillation method using the above distillation device, comprising the following steps:

[0040] The methyl chlorosilane crude monomer enters the high-removing column, the gas phase at the top of the high-removing column is used as heat source of the reboiler of the low-pressure binary column, and the gas phase at the top of the high-pressure binary column is used as heat source of the reboiler of the low-pressure removing column, and the high-removing column, the low-removing column, the high-pressure binary column and the low-pressure binary column are completely coupled.

[0041] According to the embodiment of the application, the distillation method comprises the following steps:

[0042] The methyl chlorosilane crude monomer enters the high-removing column, the component at the top of the high-removing column exchanges heat with the liquid in the column of the reboiler of the low-pressure binary column, to obtain the component after heat exchange, part of the component after heat exchange returns to the high-removing column, and part of the component after heat exchange enters the low-removing column.

[0043] The material in the column of the low-removing column enters the high-pressure binary column and the low-pressure binary column respectively, the material at the top of the high-pressure binary column exchanges heat with the liquid in the column of the reboiler of the low-removing column, to obtain the material at the top after heat exchange, and the material at the top after heat exchange returns to the high-pressure binary column or is taken out.

[0044] According to the embodiment of the application, the methyl chlorosilane crude monomer comprises monomethyltrichlorosilane (Me1), dimethyldichlorosilane (Me2), trimethylmonochlorosilane (Me3), low-boiling substances and high-boiling substances. The low-boiling substances comprise low-boiling substances with boiling points lower than that of trimethylmonochlorosilane. The high-boiling substances comprise high-boiling substances with boiling points higher than that of dimethyldichlorosilane. For example, the methyl chlorosilane crude monomer comprises Me1 4-12%, Me2 80-90%, Me3 1-7%, and the rest is low-boiling substances and high-boiling substances, in terms of mass percentage. For example, the methyl chlorosilane crude monomer comprises Me1 6%, Me2 82%, Me3 5.6%, and the rest is high-boiling substances and low-boiling substances, in terms of mass percentage.

[0045] According to embodiments of the present application, the overhead of the de-high column comprises dimethyldichlorosilane and low boilers having a lower boiling point than dimethyldichlorosilane.

[0046] According to embodiments of the present application, the bottoms of the de-high column comprise a mixture of dimethyldichlorosilane and high boilers having a higher boiling point than dimethyldichlorosilane.

[0047] According to embodiments of the present application, the temperature of the gas phase in the overhead of the de-high column is 2-50°C higher, for example 5-30°C higher, preferably 15-25°C higher than the temperature of the bottoms discharge of the low pressure binary column.

[0048] According to embodiments of the present application, the temperature of the gas phase in the overhead of the high pressure binary column is 2-50°C higher, for example 5-30°C higher, preferably 15-25°C higher than the temperature of the bottoms discharge of the de-low column.

[0049] According to embodiments of the present application, the operating pressure of the overhead of the de-high column and / or the high pressure binary column is 0.1-1.0 MPa, for example 0.2-0.6 MPa, illustratively 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa.

[0050] According to embodiments of the present application, the operating pressure of the overhead of the de-low column and / or the low pressure binary column is 0.001-0.5 MPa, for example 0.01-0.1 MPa, illustratively 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa.

[0051] According to embodiments of the present application, the overhead of the low pressure de-low column comprises trimethylchlorosilane and low boilers having a lower boiling point than trimethylchlorosilane.

[0052] According to embodiments of the present application, the bottoms of the low pressure de-low column comprise a mixture of dimethyldichlorosilane and monomethyltrichlorosilane.

[0053] According to embodiments of the present application, the overhead of the de-low column can be condensed and refluxed to the de-low column or withdrawn.

[0054] According to embodiments of the present application, the overhead of the high pressure binary column and the low pressure binary column can be condensed and refluxed or withdrawn.

[0055] According to embodiments of the present application, the overhead of the low pressure binary column and the high pressure binary column withdraws monomethyltrichlorosilane.

[0056] According to the embodiment of the present application, dimethyldichlorosilane is produced from the column still of the low-pressure binary column and the high-pressure binary column. The overhead gas phase of the high-pressure dehigh column is used as the heat source of the coupled reboiler of the low-pressure binary column, and the overhead gas phase of the high-pressure binary column is used as the heat source of the coupled reboiler of the low-pressure de-low column. In this way, by adjusting the feed amount of the high / low-pressure binary columns and the overhead pressure, the heat released by the condensation of the overhead gas phase of the high-pressure dehigh column and the high-pressure binary column can be exactly equal to the heat required for the vaporization of the liquid in the coupled reboiler of the low-pressure binary column and the low-pressure de-low column in the normal operation of the system, so that the complete coupling of the dehigh column, the de-low column and the high / low-pressure binary columns is achieved. Those skilled in the art can understand that in actual application, the feed amount can be allocated according to the principle of complete coupling according to the differences in feed components.

[0057] The present application also provides the application of the above-mentioned completely pressure-swing thermally coupled rectification device and / or method in the separation of organosilicon monomers. Preferably, the application is in the separation of methyl chlorosilane crude monomer. Preferably, the methyl chlorosilane crude monomer has the meaning as described above.

[0058] The present application has the following advantages:

[0059] The present application provides a pressure-swing thermally coupled rectification device and rectification method, which fully utilizes the characteristics of the processed materials, and by using the complete pressure-swing thermally coupled method and equipment, the overhead gas phase material of the dehigh column is used as the heat source of the reboiler of the low-pressure binary column, the overhead gas phase of the high-pressure binary column is used as the heat source of the reboiler of the de-low column, and the gas phase material is cooled at the same time. By adjusting the feed amount of the high / low-pressure binary columns, the complete coupling of the dehigh column, the de-low column and the binary columns is achieved, and the defects of the partial coupling between the columns and the failure to achieve complete coupling in the prior art are solved. There is no need to set a condenser at the top of the dehigh column and the high-pressure binary column, and the equipment investment that has to be additionally increased for the smooth operation of the system is reduced. The method can reduce the energy consumption by 45-50% compared with the conventional series process, and can reduce the amount of circulating water by 45-50% compared with the prior art. Since the system is sensitive to water, it reacts exothermically and produces strong corrosive medium when encountering water, therefore, in addition to energy saving and emission reduction, reducing the amount of circulating water can also increase the safety of equipment operation.

[0060] The present application is suitable for the process of dehigh, de-low and obtaining monomethyltrichlorosilane and dimethyldichlorosilane products from methyl chlorosilane crude monomer, and by adjusting the operating pressure of the columns, the temperature difference between the overhead gas phase of the dehigh column and the column still outlet temperature of the low-pressure binary column, and the temperature difference between the overhead gas phase of the high-pressure binary column and the column still outlet temperature of the de-low column are all 2-50°C (preferably, the temperature difference should not be too high, otherwise the energy consumption will increase), so that the overhead gas phase material of the dehigh column and the overhead gas phase material of the high-pressure binary column can provide heat sources for the column still reboilers of the low-pressure binary column and the de-low column respectively, achieving the purpose of energy optimization.

[0061] The present invention utilizes the technology of complete pressure-variable thermal coupling and is aimed at the high-pressure desorption tower and the low-pressure desorption tower, and the high- and low-pressure binary towers in the separation of crude methylchlorosilane monomers. The equipment and process are reliable, and the problems of large consumption of circulating water and steam and high energy consumption in the high-pressure desorption tower and the low-pressure desorption tower in the prior art are solved, thereby having practical operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 1 is a schematic structural diagram of the organosilicon pressure swing thermal coupling distillation device provided in Example 1;

[0063] Figure 1: 1, high-pressure degassing tower, 2, low-pressure degassing tower, 3, high-pressure binary tower, 4, low-pressure binary tower, 5, high-pressure binary tower kettle reboiler, 6, high-pressure degassing tower kettle reboiler, 7, high-pressure binary tower reflux tank, 8, high-pressure degassing tower reflux tank, 9, low-pressure degassing tower top condenser, 10, low-pressure degassing tower reflux tank, 11, low-pressure binary tower top condenser, 12, low-pressure degassing tower kettle coupled reboiler, 13, low-pressure binary tower kettle coupled reboiler, 14, low-pressure binary tower reflux tank;

[0064] A. Methylchlorosilane crude monomer, B. Heavy components, C. Monomethyltrichlorosilane product, D. Dimethyldichlorosilane product, E. Low-boiling substances including trimethylmonochlorosilane. DETAILED DESCRIPTION

[0065] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0066] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0067] Example 1

[0068] like Figure 1 The organic silicon complete pressure swing heat coupled distillation device shown includes: a high pressure removal tower 1, a low pressure removal tower 2, a high pressure binary tower 3 and a low pressure binary tower 4.

[0069] The tower kettle of the desulfurization tower 1 is provided with a desulfurization tower kettle coupling reboiler 12, and the tower kettle of the low-pressure binary tower 4 is provided with a low-pressure binary tower kettle coupling reboiler 13;

[0070] The top of the high-removing column 1 is connected with the low-pressure binary column bottom coupling reboiler 13, the gas phase stream of the high-removing column 1 provides heat source for the low-pressure binary column bottom, the gas phase stream of the high-removing column 1 enters the shell side inlet of the low-pressure binary column bottom coupling reboiler 13, the shell side outlet of the low-pressure binary column bottom coupling reboiler 13 is connected with the upper end of the high-removing column 1, forming a loop. The shell side outlet of the low-pressure binary column bottom coupling reboiler 13 and the upper end of the high-removing column 1 are connected with a high-removing column backflow tank 8, which is used to store the high-removing column top components after heat exchange from the shell side outlet of the low-pressure binary column bottom coupling reboiler 13. The shell side outlet of the low-pressure binary column bottom coupling reboiler 13 and the upper end of the high-removing column 1 are connected with a component extraction branch, which is connected with the low-removing column 2. The bottom of the high-removing column 1 is provided with a high-removing column bottom reboiler 6, one end of which is connected with the bottom of the high-removing column 1, and the other end is connected with the bottom of the high-removing column 1. The bottom of the high-removing column 1 is also provided with a heavy component extraction pipeline for extracting heavy components.

[0071] The top of the low-removing column 2 is provided with a low-removing column top condenser 9 for condensing the low-removing column top extraction. One end of the low-removing column top condenser 9 is connected with the top of the low-removing column 2, and the other end is connected with the upper end of the low-removing column 2. The connection line of the low-removing column top condenser 9 and the upper end of the low-removing column 2 is also provided with a low-removing column backflow tank 10, which is arranged downstream of the low-removing column top condenser 9. The connection line of the low-removing column backflow tank 10 and the upper end of the low-removing column 2 is also provided with a condensate extraction outlet, which is connected with an external pipeline. The low-removing column bottom coupling reboiler 12 comprises a bottom liquid outlet and a bottom liquid inlet, a shell side outlet and a shell side inlet.

[0072] The bottom liquid inlet of the low-removing column bottom coupling reboiler 12 is connected with the bottom of the low-removing column 2, and the bottom liquid outlet of the low-removing column bottom coupling reboiler 12 is connected with the bottom of the low-removing column 2. The shell side inlet of the low-removing column bottom coupling reboiler 12 is connected with the top of the high-pressure binary column 3, and the shell side outlet of the low-removing column bottom coupling reboiler 12 is connected with the upper end of the high-pressure binary column 3, forming a loop, and the gas phase stream of the high-pressure binary column 3 provides heat source for the low-removing column bottom coupling reboiler 12. The connection line of the shell side outlet of the low-removing column bottom coupling reboiler 12 and the upper end of the high-pressure binary column 3 is provided with a high-pressure binary column backflow tank 7 for storing the high-pressure binary column top components after heat exchange. The connection line of the shell side outlet of the low-removing column bottom coupling reboiler 12 and the upper end of the high-pressure binary column 3 is also provided with a material extraction branch for extracting the high-pressure binary column top components after heat exchange. The bottom of the low-removing column 2 is also provided with a low-removing column bottom material extraction pipeline, which is connected with the high-pressure binary column 3 and the low-pressure binary column 4 respectively as the feed of the two columns.

[0073] The high-pressure binary column 3 and the low-pressure binary column 4 are connected in parallel. The column bottom of the high-pressure binary column 3 is provided with a high-pressure binary column bottom reboiler 5, one end of which is connected to the column bottom of the high-pressure binary column 3, and the other end of which is connected to the column bottom of the high-pressure binary column 3. The column bottom of the high-pressure binary column 3 is also provided with a high-pressure binary column bottom material tapping pipeline for tapping column bottom material.

[0074] The column top of the low-pressure binary column 4 is provided with a low-pressure binary column top condenser 11 for condensing low-pressure binary column top tapping material. One end of the low-pressure binary column top condenser 11 is connected to the column top of the low-pressure binary column 4, and the other end of the low-pressure binary column top condenser 11 is connected to the upper end of the column of the low-pressure binary column 4. The low-pressure binary column top condenser 11 is also provided with a low-pressure binary column reflux tank 14 on the connecting pipeline between the low-pressure binary column top condenser 11 and the upper end of the column of the low-pressure binary column 4, and the low-pressure binary column reflux tank 14 is arranged downstream of the low-pressure binary column top condenser 11. The low-pressure binary column reflux tank 14 is also provided with a condensed liquid tapping outlet connected to an external pipeline. The low-pressure binary column bottom coupling reboiler 13 is provided with a column bottom liquid inlet and a column bottom liquid outlet, the column bottom liquid inlet of the low-pressure binary column bottom coupling reboiler 13 is connected to the column bottom of the low-pressure binary column 4, and the column bottom liquid outlet of the low-pressure binary column bottom coupling reboiler 13 is connected to the column bottom of the low-pressure binary column 4. The column bottom of the low-pressure binary column 4 is also provided with a column bottom material tapping pipeline for tapping column bottom material of the low-pressure binary column.

[0075] The high-pressure binary column is selected from a pressurized or atmospheric distillation column, the upper part of which is a packed column and the lower part of which is a plate column.

[0076] The low-pressure binary column is selected from an atmospheric or negative pressure distillation column, the high-pressure binary column is selected from a pressurized or atmospheric distillation column, and the low-pressure binary column is selected from an atmospheric or negative pressure distillation column.

[0077] The negative pressure range is 0-101.33 KPa (A), and the pressurized range is 0.05-1 Mpa (G).

[0078] The low-pressure binary column is selected from an atmospheric or negative pressure distillation column, the high-pressure binary column is selected from a pressurized or atmospheric distillation column, and the low-pressure binary column is selected from an atmospheric or negative pressure distillation column.

[0079] Example 2

[0080] As shown in FIG. 1, the high-pressure binary column 3 and the low-pressure binary column 4 are connected in parallel. Figure 1The shown rectification device is used for separation of methyl chlorosilane crude monomer. The feed amount of methyl chlorosilane crude monomer is 25000 kg / hr, wherein Me1 is 60%, Me2 is 82%, Me3 is 5.6% in mass fraction, and the rest is high-boiling and low-boiling substances. The methyl chlorosilane crude monomer enters a high-removal column, heavy components including part of dimethyl dichlorosilane and high-boiling substances higher than dimethyl dichlorosilane in boiling point are taken out from the column bottom, dimethyl dichlorosilane and light components lower than dimethyl dichlorosilane in boiling point are taken out from the column top, the column top take-out is used as a heat source of a low-pressure binary column bottom coupling reboiler, is cooled after heat exchange with column bottom liquid in the coupling reboiler, and then enters a low-removal column. The low-removal column top take-out includes trimethyl monochlorosilane and low-boiling substances lower than trimethyl monochlorosilane in boiling point, and the low-removal column bottom take-out is mainly a mixture of dimethyl dichlorosilane and monomethyl trichlorosilane. The mixture is distributed in flow and respectively enters a high-pressure binary column and a low-pressure binary column. The high-pressure binary column top take-out is used as a heat source of the low-removal column bottom coupling reboiler, is cooled after heat exchange with column bottom liquid in the coupling reboiler, and returns to the high-pressure binary column or is taken out. The binary column top take-out is qualified Me1 product, and the binary column bottom take-out is dimethyl dichlorosilane Me2 product. The low-removal column top gas phase is used as a heat source of the low-pressure binary column bottom coupling reboiler, and the high-pressure binary column top gas phase is used as a heat source of the low-removal column bottom coupling reboiler; by adjusting the feed amount of the high-pressure and low-pressure binary columns, complete coupling of the low-removal, high-removal and binary column heat is realized. The low-removal column top gas phase temperature is 20℃ higher than the low-pressure binary column bottom temperature, and the high-pressure binary column top gas phase temperature is 20℃ higher than the low-removal column bottom temperature; the low-removal column top operating pressure is 0.2 MPa(G), the low-removal column top operating pressure is 0.02 MPa(G), the high-pressure binary column top operating pressure is 0.2 MPa(G), and the low-pressure binary column top operating pressure is 0.02 MPa(G). The material take-out conditions of each column are shown in Table 1.

[0081] Table 1 Material take-out conditions of each column

[0082]

[0083]

[0084] Under the same processing amount and product requirements, the energy consumption comparison data of the non-coupling process and Example 2 are shown in Table 2.

[0085] Table 2 Energy consumption comparison of the coupling process of Example 2 and the non-coupling process

[0086]

[0087]

[0088] From the above comparison data, it can be seen that, in the same processing capacity and product quality, the reboiler load of the pressure swing coupling process is only 53% of that of the non-coupling process, and the condenser load is 51% of that of the non-coupling process, so that the steam and circulating water consumption is greatly reduced.

[0089] Example 3

[0090] The raw material conditions are as follows: the feed amount of methyl chlorosilane crude monomer is 25000 kg / hr, wherein Me1 is 5%, Me2 is 83%, Me3 is 5.6% in mass fraction, and the rest is high boiler and low boiler. The rest of the conditions are the same as those of Example 2. The material production conditions of each tower are shown in Table 3.

[0091] Table 3 Material production conditions of each tower

[0092]

[0093]

[0094] Under the same processing capacity and product requirements, the energy consumption comparison data of the non-coupling process and the coupling process of Example 3 are shown in Table 4.

[0095] Table 4 Energy consumption comparison of the coupling process of Example 3 and the non-coupling process

[0096]

[0097] From the comparison data shown in Table 4, it can be seen that, in the same processing capacity and product quality, the reboiler load of the pressure swing coupling process is only 53% of that of the non-coupling process, and the condenser load is 50% of that of the non-coupling process, so that the steam and circulating water consumption is greatly reduced.

[0098] Example 4

[0099] The raw material conditions are as follows: the feed amount of methyl chlorosilane crude monomer is 25000 kg / hr, wherein Me1 is 5%, Me2 is 83%, Me3 is 5.6% in mass fraction, and the rest is high boiler and low boiler. The rest of the conditions are the same as those of Example 2. The material production conditions of each tower are shown in Table 3.

[0100] Table 5 Material production conditions of each tower

[0101]

[0102]

[0103] Under the same processing capacity and product requirements, the energy consumption comparison data of the non-coupling process and the coupling process of Example 4 are shown in Table 6.

[0104] Table 6 Energy consumption comparison between coupled process and non-coupled process of Example 4

[0105]

[0106] From the comparison data shown in Table 6, it can be seen that, in the case of the same processing capacity and product quality, the reboiler load of the variable pressure coupled process is only 53% of that of the non-coupled process, and the condenser load is 50% of that of the non-coupled process, thus greatly reducing the steam and circulating water consumption.

[0107] The non-coupled process in the above examples refers to a conventional series process: a high-removing column, a low-removing column, and a binary column are connected in series, each column is provided with a reboiler and a condenser, and steam and circulating water are required as the heat source of the reboiler and the cold source of the condenser. The remaining processing conditions are the same as those of the respective examples.

[0108] Those skilled in the art can expect that, when the difference between the overhead gas phase temperature of the high-removing column and the bottom temperature of the low-pressure binary column, and the difference between the overhead gas phase temperature of the high-pressure binary column and the bottom temperature of the low-removing column, are adjusted within the scope defined in the summary, the same effects as the examples can be achieved.

[0109] The embodiments of the present application have been described above. However, the present application is not limited to the above-described embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for complete pressure-swing thermal coupling distillation of organic silicon, characterized in that: The organosilicon complete pressure swing thermal coupling distillation method is carried out in the following organosilicon complete pressure swing thermal coupling distillation device, which includes a high-pressure degassing tower, a low-pressure degassing tower, a high-pressure binary tower and a low-pressure binary tower; The high-pressure binary tower and the low-pressure binary tower are connected in parallel; The desulfurization tower and the low-pressure binary tower are respectively provided with a coupled tower kettle reboiler; The top of the high-pressure degassing tower is connected to the low-pressure binary tower kettle coupled reboiler, the gaseous phase flowing out of the top of the high-pressure degassing tower enters the shell-side inlet of the low-pressure binary tower kettle coupled reboiler, and the gaseous phase flow from the top of the high-pressure degassing tower provides a heat source for the low-pressure binary tower kettle; the shell-side outlet of the low-pressure binary tower kettle coupled reboiler is connected to the upper end of the high-pressure degassing tower to form a loop; The top of the high-pressure binary tower is connected to the shell-side inlet of the degassing tower kettle coupled reboiler, and the gaseous phase flow at the top of the high-pressure binary tower provides a heat source for the degassing tower kettle reboiler; the shell-side outlet of the degassing tower kettle coupled reboiler is connected to the upper end of the high-pressure binary tower to form a loop; The organic silicon complete pressure-swing thermally coupled distillation method comprises the following steps: The crude methylchlorosilane monomer enters the high-pressure degassing tower, and the components extracted from the top of the high-pressure degassing tower are heat-exchanged with the bottom liquid in the low-pressure binary tower kettle coupling reboiler to obtain the components after heat exchange. Part of the components after heat exchange are returned to the high-pressure degassing tower, and part of the components after heat exchange are entered into the low-pressure degassing tower; The tower bottom produced material of the desulfurization tower enters the high-pressure binary tower and the low-pressure binary tower respectively, and the tower top produced material of the high-pressure binary tower exchanges heat with the tower bottom liquid in the tower bottom coupling reboiler of the desulfurization tower to obtain the tower top produced material after heat exchange, and the tower top produced material after heat exchange is refluxed to the high-pressure binary tower or produced; The gas phase temperature at the top of the high-pressure degassing tower is 5-30℃ higher than the discharge temperature of the bottom of the low-pressure binary tower; The gas phase temperature at the top of the high-pressure binary tower is 5-30℃ higher than the discharge temperature of the bottom of the desulfurization tower; The operating pressure of the tower top of the high-pressure degassing tower and the high-pressure binary tower is 0.1-1.0 MPa; The tower top operating pressure of the desulfurization tower and the low-pressure binary tower is 0.01-0.5 MPa.

2. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The gas phase temperature at the top of the high-pressure degassing tower is 15-25℃ higher than the discharge temperature of the bottom of the low-pressure binary tower; and / or, the gas phase temperature at the top of the high-pressure binary tower is 15-25° C. higher than the discharge temperature of the bottom of the desulfurization tower; And / or, the tower top operating pressure of the degassing tower and / or the high-pressure binary tower is 0.2-0.6 MPa; And / or, the tower top operating pressure of the desulfurization tower and / or the low-pressure binary tower is 0.01-0.1 MPa.

3. The organic silicon complete pressure swing thermal coupled distillation method according to claim 1, characterized in that: A degassing tower reflux tank is further provided on the connection line between the shell-side outlet of the low-pressure binary tower kettle coupled reboiler and the upper end of the degassing tower, for storing the degassing tower top components after heat exchange extracted from the shell-side outlet of the low-pressure binary tower kettle reboiler; Or further, the shell side outlet of the reboiler of the low-pressure binary tower kettle is connected to the reflux tank of the degassing tower, and an extraction branch after removing the high-boiling components is set on the connecting line from the reflux tank to the upper end of the degassing tower, and the extraction branch after removing the high-boiling components is connected to the degassing tower.

4. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The tower kettle of the degassing tower is provided with a tower kettle reboiler of the degassing tower, one end of the tower kettle reboiler is connected to the tower kettle of the degassing tower, and the other end is connected to the bottom of the degassing tower; And / or, the tower kettle of the high-density desorption tower is further provided with a high-density desorption tower heavy component extraction pipeline for extracting the heavy components.

5. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: A desulfurization tower top condenser is provided at the top of the desulfurization tower for condensing the extract from the desulfurization tower top; One end of the depletion tower top condenser is connected to the top of the depletion tower, and the other end is connected to the upper end of the depletion tower.

6. The organic silicon complete pressure swing thermal coupling distillation method according to claim 5, characterized in that: A degassing tower reflux tank is further provided on the connection line between the degassing tower top condenser and the upper end of the degassing tower, and the degassing tower reflux tank is provided downstream of the degassing tower top condenser; Or further, the connecting pipeline between the reflux tank of the depletion tower and the upper end of the depletion tower also includes a condensate extraction outlet, and the condensate extraction outlet is connected to a subsequent device.

7. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The degassing tower kettle coupled reboiler comprises a kettle liquid outlet and a kettle liquid inlet, the kettle liquid inlet of the degassing tower kettle coupled reboiler is connected to the bottom of the degassing tower, and the kettle liquid outlet of the degassing tower kettle coupled reboiler is connected to the kettle of the degassing tower; And / or, a high-pressure binary tower reflux tank is provided on the connection line between the shell-side outlet of the degassing tower kettle coupled with the reboiler and the upper end of the high-pressure binary tower, for storing the high-pressure binary tower top components after heat exchange; And / or, the shell-side outlet of the kettle-coupled reboiler of the degassing tower is connected to the reflux tank of the high-pressure binary tower, the reflux tank is returned to the connecting line at the upper end of the degassing tower, and a material extraction branch is further provided for extracting the top components of the high-pressure binary tower after heat exchange; And / or, the bottom of the desulfurization tower is further provided with a material extraction pipeline for the bottom of the desulfurization tower, and the material extraction pipeline for the bottom of the desulfurization tower is connected to the high-pressure binary tower and the low-pressure binary tower respectively.

8. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The tower kettle of the high-pressure binary tower is provided with a high-pressure binary tower kettle reboiler, one end of the high-pressure binary tower kettle reboiler is connected to the tower kettle of the high-pressure binary tower, and the other end is connected to the tower bottom of the high-pressure binary tower; Alternatively, the bottom of the high-pressure binary tower is further provided with a high-pressure binary tower bottom material extraction pipeline for extracting the bottom material; And / or, a low-pressure binary tower top condenser is provided at the top of the low-pressure binary tower to condense the produced material from the low-pressure binary tower top; One end of the low-pressure binary tower top condenser is connected to the top of the low-pressure binary tower, and the other end is connected to the upper end of the low-pressure binary tower; And / or, a low-pressure binary tower reflux tank is further provided on the connection line between the low-pressure binary tower top condenser and the upper end of the low-pressure binary tower, and the low-pressure binary tower reflux tank is provided downstream of the low-pressure binary tower top condenser; the low-pressure binary tower reflux tank and the upper end of the low-pressure binary tower also include a condensate extraction port on the connection line, and the condensate extraction port is connected to an external pipeline; And / or, the low-pressure binary tower-tower coupled reboiler comprises a tower bottom liquid inlet and a tower bottom liquid outlet, the tower bottom liquid inlet of the low-pressure binary tower-tower coupled reboiler is connected to the bottom of the low-pressure binary tower, and the tower bottom liquid outlet of the low-pressure binary tower-tower coupled reboiler is connected to the low-pressure binary tower; And / or, the bottom of the low-pressure binary tower is further provided with a bottom material extraction pipeline for extracting the bottom material of the low-pressure binary tower.

9. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The degassing tower is selected from a pressure or atmospheric distillation tower; The degassing tower is selected from a normal pressure or negative pressure distillation tower; The high-pressure binary tower is selected from a pressurized or atmospheric distillation tower; The low-pressure binary tower is selected from a normal pressure or negative pressure distillation tower.

10. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The high-element removal tower, low-element removal tower, high-pressure binary tower and low-pressure binary tower are plate towers and / or packed towers.

11. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The device also includes a backup cold source and / or a backup heat source.

12. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The crude methylchlorosilane monomer includes monomethyltrichlorosilane (Me1), dimethyldichlorosilane (Me2), trimethylmonochlorosilane (Me3), low boiling substances and high boiling substances; The low boiling substances include low boiling substances having a boiling point lower than that of trimethylmonochlorosilane, and the high boiling substances include high boiling substances having a boiling point higher than that of dimethyldichlorosilane.

13. The organic silicon complete pressure swing thermal coupled distillation method according to claim 1, characterized in that: The components extracted from the top of the desulfurization tower include dimethyldichlorosilane and low-boiling substances with a boiling point lower than that of dimethyldichlorosilane; The bottom product of the high-pressure desulfurization tower contains part of or does not contain dimethyldichlorosilane and high-boiling substances with a boiling point higher than that of dimethyldichlorosilane.

14. The organic silicon complete pressure swing thermal coupling distillation method according to claim 1, characterized in that: The overhead product of the low-pressure desulfurization tower includes trimethyl monochlorosilane and low-boiling products with a lower boiling point than trimethyl monochlorosilane; The output from the low-pressure degassing tower kettle includes a mixture of dimethyldichlorosilane and monomethyltrichlorosilane; The material extracted from the top of the degassing tower is refluxed to the degassing tower or extracted after condensation; The material extracted from the top of the low-pressure binary tower is condensed and then refluxed to the low-pressure binary tower or extracted; Monomethyltrichlorosilane is produced from the top of the low-pressure binary tower and the high-pressure binary tower; The tower bottoms of the low-pressure binary tower and the high-pressure binary tower produce dimethyldichlorosilane.

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