WO2021237483A1

WO2021237483A1 - Process method and system for co-production of propane dehydrogenation unit and ethylene unit

Info

Publication number: WO2021237483A1
Application number: PCT/CN2020/092435
Authority: WO
Inventors: 姜浩; 张锦红; 张军; 马利峰
Original assignee: 上海卓然工程技术股份有限公司; 江苏博颂化工科技有限公司
Priority date: 2020-05-25
Filing date: 2020-05-26
Publication date: 2021-12-02
Also published as: CN111440044A

Abstract

Disclosed are a process method and system for co-production of a propane dehydrogenation unit and an ethylene unit, the system comprising a oil and gas water-washing tower (1), a rich gas compressor (2), an outlet cooler (3) of the rich gas compressor, a steam-water separator (4), a rich gas dryer (5), a cold box (6), a gas-liquid separation tank (7), a condensate delivery pump (8), a crude deethanization tower (9), a top condenser (10) of the crude deethanization tower, a top reflux tank (11) of the crude deethanization tower, a top reflux pump (12) of the crude deethanization tower, a bottom delivery pump (13) of the crude deethanization tower, and a propylene rectification tower (14).

Description

Process method and system for co-production of propane dehydrogenation unit and ethylene unit

Technical field

The invention belongs to the technical field of propane dehydrogenation and ethylene, in particular to a process method and system for co-production of an ethylene device of a propane dehydrogenation device.

Background technique

Ethylene and propylene are important petrochemical monomers that can be used to produce a variety of polymers and intermediates. As the market demand for these products increases, so does the demand for ethylene and propylene. Ethylene plant and propane dehydrogenation plant are currently the main production methods.

The dry gas at the top of the propane dehydrogenation unit of the propane dehydrogenation unit contains a part of ethylene. Ethane is generally sent to the propane dehydrogenation unit with the dry gas as fuel gas to be burned. This part of ethylene, ethane is wasted, adding value Low, if the ethane in the dry gas is separated in the propane dehydrogenation unit alone, the ethylene will increase equipment investment but the income will be limited.

In view of the above-mentioned problems, how to realize the co-production of the ethylene plant and the propane dehydrogenation unit through the change of the process technical scheme and recover this part of propylene and propane in the propane dehydrogenation dry gas has become an urgent problem to be solved.

Summary of the invention

The purpose of the present invention is to provide a process method and system for co-production of a propane dehydrogenation unit and an ethylene unit, so as to solve the dry gas separation problem of the existing propane dehydrogenation unit.

The present invention is realized through the following technical solutions:

A process method for co-production of a propane dehydrogenation unit and an ethylene unit includes the following steps:

S1. The PDH product rich gas from the propane dehydrogenation reaction unit is sent to the oil and gas washing tower, and the PDH product rich gas is washed by the oil and gas washing tower and then discharged from the top of the oil and gas washing tower;

S2. The PDH product rich gas discharged from the top of the oil and gas washing tower enters the rich gas compressor, and is pressurized by the rich gas compressor and sent to the outlet cooler of the rich gas compressor;

S3. The PDH product rich gas cooled by the outlet cooler of the rich gas compressor is sent to the steam-water separation tank to separate the oily wastewater, and the PDH product rich gas after the steam-water separation is discharged from the top of the steam-water separation tank and sent to the rich Gas dryer

S4. In the rich gas dryer, the PDH product rich gas is sent to the cold box after removing the remaining moisture, and is sent to the gas-liquid separation tank after further cooling;

S5. In the gas-liquid separation tank, the light hydrocarbon gas contained in the rich gas of the PDH product is sent from the top of the gas-liquid separation tank to the upper part of the crude deethanizer, and the first light hydrocarbon condensate at the bottom of the gas-liquid separation tank passes The condensate is pumped to the lower part of the crude de-ethanizer;

S6. The light hydrocarbon gas is sent from the top of the crude de-ethanizer to the condenser of the crude de-ethanizer, and then enters the crude de-ethanizer reflux tank after being condensed by the crude de-ethanizer, where the light hydrocarbons are condensed The liquid is used as the reflux liquid from the top of the crude de-ethanizer to be transported back to the top of the crude de-ethanizer by the crude de-ethanizer reflux pump. Entrance of the four-stage pyrolysis gas compressor;

S7. The light hydrocarbons extracted from the bottom of the crude de-ethanizer are sent to the propylene rectification tower by the transport pump at the bottom of the crude de-ethanizer. The top of the propylene rectification tower produces polymerized propylene products, and the bottom of the propylene rectification tower The propane is returned to the propane dehydrogenation reaction unit as recycled propane.

Further, the process method further includes: using the rectification tower system of the ethylene plant to send the dry gas of the propane dehydrogenation and the ethylene cracking gas to the rectification system of the ethylene plant for separation.

Further, the theoretical plate number of the oil-gas washing tower is 4, the operating pressure is normal pressure, the temperature produced at the top of the tower is 42°C, and the temperature produced at the bottom of the tower is 55°C; The outlet pressure is 1.15 MPaG; the hot end outlet temperature of the rich gas compressor cooler is 40°C.

Further, the operating pressure of the steam-water separator tank is 1.1 MPaG, and the operating temperature is 40°C; the operating pressure of the rich gas dryer is 1.05 MPaG, and the operating temperature is 40°C; the inlet temperature of the rich gas end of the cold box is 40°C, The outlet temperature is -33°C, the operating pressure of the gas-liquid separation tank is 0.9MPaG, and the operating temperature is -33°C.

Further, the number of theoretical plates of the crude deethanizer is 48, the operating pressure is 0.75MPaG, the temperature at the top of the tower is -23°C, and the temperature at the bottom of the tower is 18°C; the number of theoretical plates of the propylene rectification tower is 200, The operating pressure is 0.8MPaG, the temperature at the top of the tower is 15°C, and the temperature at the bottom of the tower is 27°C.

Further, the rich gas composition of the PDH product is as follows: a hydrogen content of 1.57 wt%, a methane content of 0.86 wt%, an ethylene content of 0.49 wt%, an ethane content of 0.84 wt%, a propyne content of 0.01 wt%, and a propylene content of 32.11 wt%, The content of propane is 62.65wt%, and the heavy component impurities are 0.95wt%.

Further, the composition of the dry gas extracted from the top of the reflux tank at the top of the crude deethanization tower is: hydrogen content 24.04wt%, methane content 27.34wt%, ethylene content 7.5wt%, ethane content 12.76wt%, propylene content 22.59wt% , Propane content is 5.77wt%.

Furthermore, in the propylene product produced at the top of the propylene rectification tower, the propylene content is 99.6% by weight, and the propane content is 0.4% by weight.

A system for the co-production of a propane dehydrogenation unit and an ethylene unit, which is used in the process method for the co-production of any one of the above-mentioned propane dehydrogenation units and an ethylene unit, comprising:

Oil and gas washing tower, rich gas compressor, rich gas compressor outlet cooler, steam-water separator, rich gas dryer, cold box, gas-liquid separation tank, condensate transfer pump, crude de-ethanizer, crude de-ethanizer Top condenser, top reflux tank of crude de-ethanizer, top reflux pump of crude de-ethanizer, bottom transfer pump of crude de-ethanizer, and propylene distillation tower;

The PDH product rich gas of the propane dehydrogenation reaction unit is connected from the rich gas outlet of the waste heat recovery equipment to the air inlet on the lower side of the oil and gas washing tower through a pipeline, and the washing water is connected to the water inlet on the upper side of the oil and gas washing tower through the pipeline; The gas outlet at the top of the oil-gas washing tower is connected to the inlet of the rich gas compressor through a pipeline, and the outlet of the rich gas compressor is connected to the hot end inlet of the outlet cooler of the rich gas compressor through a pipeline;

The hot end outlet of the rich gas compressor outlet cooler is connected to the inlet of the steam-water separator tank through a pipe, the gas-phase outlet on the top of the steam-water separator tank is connected to the inlet of the rich gas dryer through a pipe, and the outlet of the rich gas dryer is connected to the cold box through a pipe. The inlet of the rich gas end is connected, and the outlet of the rich gas end of the cold box is connected to the inlet of the gas-liquid separator through a pipe;

The gas-liquid outlet at the top of the gas-liquid separation tank is connected to the air inlet on the upper part of the crude de-ethanizer through a pipeline, the liquid phase outlet at the bottom of the gas-liquid separation tank is connected to the inlet of the condensate transfer pump through a pipeline, and the outlet of the condensate transfer pump passes through The pipeline is connected with the liquid inlet in the middle of the crude de-ethanizer;

The gas phase outlet at the top of the crude de-ethanizer is connected to the hot end inlet of the crude de-ethanizer top condenser through a pipeline, and the hot outlet of the crude de-ethanizer top condenser is connected to the inlet of the crude de-ethanizer top reflux tank;

The gas-phase outlet at the top of the crude de-ethanizer reflux tank is connected to the inlet of the fourth stage compressor of the ethylene plant through a pipeline; the liquid-phase outlet at the bottom of the crude de-ethanizer reflux tank and the inlet of the reflux pump at the top of the crude de-ethanizer Connection, the outlet of the reflux pump at the top of the crude de-ethanizer is connected to the reflux port at the top of the crude de-ethanizer;

The liquid phase outlet at the bottom of the crude de-ethanizer is connected to the inlet of the crude de-ethanizer bottom transfer pump, and the outlet of the crude de-ethanizer bottom transfer pump is connected to the inlet of the propylene rectification tower;

The propane product outlet at the top of the propylene rectification tower is connected to the inlet of the cryogenic unit through a pipeline, and the propane outlet at the bottom of the propylene rectification tower is connected to the inlet of the reaction unit for propane dehydrogenation.

The beneficial effects of the present invention are:

1. The process method for co-production of the propane dehydrogenation unit and the ethylene unit of the present invention uses the separation system of the ethylene unit to separate ethylene and ethane from the dry gas of the propane dehydrogenation unit, which increases the added value of the product and improves the profit.

2. The process method of the co-production of the propane dehydrogenation device and the ethylene device of the present invention shares the public engineering system and the refrigeration system, reducing equipment investment and land occupation.

Description of the drawings

Figure 1 is a process flow diagram of the co-production of the propane dehydrogenation unit and the ethylene unit of the present invention.

Description of Reference Signs

1- Oil-gas washing tower; 2- Rich gas compressor; 3- Rich gas compressor outlet cooler; 4- Steam-water separation tank; 5- Rich gas dryer; 6- Cold box; 7- Gas-liquid separation tank; 8- Condensate transfer pump; 9-crude deethanizer tower; 10-crude deethanizer top condenser; 11-crude deethanizer top reflux tank; 12-crude deethanizer top reflux pump; 13-rough deethanizer Transfer pump at the bottom of ethane tower; 14-propylene distillation tower.

Detailed ways

It should be noted that the embodiments in the invention and the features in the embodiments can be combined with each other if there is no conflict.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. are based on the orientation or positional relationship shown in the drawings, but In order to facilitate the creation of the present invention and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of these features. In the description of the invention, unless otherwise specified, the meaning of "multiple" means two or more.

In the description of the invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection or an optional connection. Detachable connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the creation of the present invention can be understood through specific circumstances.

The invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

As shown in FIG. 1, the present application provides a process for co-production of a propane dehydrogenation unit and an ethylene unit. First, the PDH product rich gas produced in the propane dehydrogenation reaction unit is sent to the lower side of the oil and gas washing tower 1.

In this embodiment, the composition of the rich gas of the PDH product produced in the reaction unit is hydrogen content of 1.57% by weight, methane content of 0.86% by weight, ethylene content of 0.49% by weight, ethane content of 0.84% by weight, and propyne content of 0.01% by weight. , The propylene content is 32.11wt%, the propane content is 62.65wt%, and the heavy component impurities are 0.95wt%.

In this embodiment, the working parameters of the oil-gas washing tower are selected as the tower top operating temperature at 42°C, the operating pressure at normal pressure, and the tower bottom temperature at 55°C. After being washed by the oil-gas washing tower, the rich gas of the PDH product is discharged from the top of the oil-gas washing tower, and the oily sewage at the bottom of the oil-gas washing tower enters the recovery or treatment system.

The PDH product rich gas from the oil and gas washing tower is sent to the rich gas compressor 2, and the PDH product rich gas is pressurized to 1.15MPaG and then sent to the rich gas compressor outlet cooler 3. The PDH product rich gas is sent to the rich gas compressor The outlet cooler is cooled to about 40°C and sent to the steam-water separation tank 4 to separate oily sewage. In this embodiment, the working parameters of the steam-water separation tank are operating pressure of 1.1 MPaG and operating temperature of 40°C.

The rich gas of PDH product is discharged from the top of the steam-water separation tank and sent to the rich gas dryer 5. The working parameters of the rich gas dryer are the operating pressure of 1.05MPaG and the operating temperature of 40℃. The rich gas of the PDH product passes through the rich gas dryer to remove the remaining After the water enters the cold box 6, it is further cooled to -33°C and then sent to the gas-liquid separation tank 7. In this embodiment, the working parameters of the gas-liquid separation tank are operating pressure 0.9MpaG and operating temperature -33°C.

The light hydrocarbon gas separated from the gas-liquid separation tank is discharged from the top of the gas-liquid separation tank and sent to the upper part of the crude de-ethanizer 9. The first light hydrocarbon condensate at the bottom of the gas-liquid separation tank is passed through the condensate pump 8 is sent to the lower part of the crude de-ethanizer. In this embodiment, the crude de-ethanizer has a working parameter of 0.75MpaG, a top temperature of -23°C, and a bottom temperature of 18°C.

The light hydrocarbon gas is sent through the top of the crude deethanizer to the condenser 10 at the top of the crude deethanizer to be condensed and then enters the crude deethanizer reflux tank 11, and the second light hydrocarbon condensate in the crude deethanizer reflux tank is used as the crude The reflux liquid from the top of the de-ethanizer is sent back to the top of the crude de-ethanizer by the crude de-ethanizer top reflux pump 12, and the dry gas in the crude de-ethanizer reflux tank is extracted from the top of the tank and sent to the fourth part of the ethylene plant. At the inlet of the stage cracked gas compressor, in this embodiment, the composition of the dry gas produced at the top of the reflux tank at the top of the crude de-ethanizer is: hydrogen content 24.04wt%, methane content 27.34wt%, ethylene content 7.5wt%, ethane The content is 12.76wt%, the propylene content is 22.59wt%, and the propane content is 5.77wt%.

The light hydrocarbons produced at the bottom of the crude de-ethanizer are sent to the propylene rectification tower 14 by the delivery pump 13 at the bottom of the crude de-ethanizer. The operating pressure is 0.8MpaG, the top temperature is 15°C, and the bottom temperature is 27°C. The polymerization-grade propylene product is produced at the top of the rectification tower, and the propane produced at the bottom of the tower is returned to the reaction unit as circulating propane.

This application also includes systems for the co-production process of the above-mentioned propane dehydrogenation unit and ethylene unit, including oil-gas washing tower, rich gas compressor, rich gas compressor outlet cooler, steam water separator, rich gas dryer, and cold box , Gas-liquid separation tank, condensate transfer pump, crude de-ethanizer, crude de-ethanizer top condenser, crude de-ethanizer top reflux tank, crude de-ethanizer top reflux pump, crude deethanizer bottom Delivery pump and propylene distillation tower.

The PDH product rich gas of the propane dehydrogenation reaction unit is connected from the rich gas outlet of the waste heat recovery equipment to the air inlet on the lower side of the oil and gas washing tower through a pipeline, and the washing water is connected to the water inlet on the upper side of the oil and gas washing tower through the pipeline; The top gas outlet of the oil-gas washing tower is connected with the inlet of the rich gas compressor through a pipeline, and the outlet of the rich gas compressor is connected with the hot end inlet of the outlet cooler of the rich gas compressor through a pipeline.

The hot end outlet of the rich gas compressor outlet cooler is connected to the inlet of the steam-water separator tank through a pipe, the gas-phase outlet on the top of the steam-water separator tank is connected to the inlet of the rich gas dryer through a pipe, and the outlet of the rich gas dryer is connected to the cold box through a pipe. The rich gas end inlet is connected, and the rich gas end outlet of the cold box is connected to the inlet of the gas-liquid separator through a pipe.

The gas-liquid outlet at the top of the gas-liquid separation tank is connected to the air inlet on the upper part of the crude de-ethanizer through a pipeline, the liquid phase outlet at the bottom of the gas-liquid separation tank is connected to the inlet of the condensate transfer pump through a pipeline, and the outlet of the condensate transfer pump passes through The pipeline is connected with the liquid inlet in the middle of the crude de-ethanizer.

The gas phase outlet at the top of the crude de-ethanizer is connected to the hot end inlet of the crude de-ethanizer top condenser through a pipeline, and the hot outlet of the crude de-ethanizer top condenser is connected to the inlet of the crude deethanizer top reflux tank.

The gas-phase outlet at the top of the crude de-ethanizer reflux tank is connected to the inlet of the fourth stage compressor of the ethylene plant through a pipeline; the liquid-phase outlet at the bottom of the crude de-ethanizer reflux tank and the inlet of the reflux pump at the top of the crude de-ethanizer Connect, the outlet of the reflux pump at the top of the crude de-ethanizer is connected with the reflux port at the top of the crude de-ethanizer.

The liquid phase outlet at the bottom of the crude de-ethanizer is connected to the inlet of the crude de-ethanizer bottom transfer pump, and the outlet of the crude de-ethanizer bottom transfer pump is connected to the inlet of the propylene rectification tower.

The process and system for co-production of a propane dehydrogenation unit and an ethylene unit proposed by the present invention have been described through examples. It is obvious that those skilled in the art can compare what is described herein without departing from the content, spirit and scope of the present invention. Products and manufacturing methods are modified or appropriately modified and combined to realize the technology of the present invention. In particular, it should be pointed out that all similar replacements and modifications are obvious to those skilled in the art, and they are all deemed to be included in the spirit, scope and content of the present invention.

Claims

A process method for co-production of a propane dehydrogenation unit and an ethylene unit is characterized in that it comprises the following steps:

S1. The PDH product rich gas from the propane dehydrogenation reaction unit is sent to the oil and gas washing tower, and the PDH product rich gas is washed by the oil and gas washing tower and then discharged from the top of the oil and gas washing tower;

S2. The PDH product rich gas discharged from the top of the oil and gas washing tower enters the rich gas compressor, and is pressurized by the rich gas compressor and sent to the outlet cooler of the rich gas compressor;

S3. The PDH product rich gas cooled by the outlet cooler of the rich gas compressor is sent to the steam-water separation tank to separate the oily wastewater, and the PDH product rich gas after the steam-water separation is discharged from the top of the steam-water separation tank and sent to the rich Gas dryer

S4. In the rich gas dryer, the PDH product rich gas is sent to the cold box after removing the remaining moisture, and is sent to the gas-liquid separation tank after further cooling;

S5. In the gas-liquid separation tank, the light hydrocarbon gas contained in the rich gas of the PDH product is sent from the top of the gas-liquid separation tank to the upper part of the crude deethanizer, and the first light hydrocarbon condensate at the bottom of the gas-liquid separation tank passes The condensate is pumped to the lower part of the crude de-ethanizer;

S6. The light hydrocarbon gas is sent from the top of the crude de-ethanizer to the condenser of the crude de-ethanizer, and then enters the crude de-ethanizer reflux tank after being condensed by the crude de-ethanizer, where the light hydrocarbons are condensed The liquid is used as the reflux liquid from the top of the crude de-ethanizer to be transported back to the top of the crude de-ethanizer by the crude de-ethanizer top reflux pump, and the dry gas is extracted from the reflux tank of the crude de-ethanizer and sent to the ethylene plant. Entrance of the fourth stage cracked gas compressor;

S7. The light hydrocarbons extracted from the bottom of the crude de-ethanizer are sent to the propylene rectification tower by the transport pump at the bottom of the crude de-ethanizer. The top of the propylene rectification tower produces polymerized propylene products, and the bottom of the propylene rectification tower The propane is returned to the propane dehydrogenation reaction unit as recycled propane.
The process method for co-production of a propane dehydrogenation unit and an ethylene plant according to claim 1, wherein the process method further comprises: using a rectification tower system of the ethylene plant to crack the dry gas from the propane dehydrogenation unit with ethylene The gas is sent to the rectification system of the ethylene plant for separation.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the theoretical plate number of the oil-gas washing tower is a layer, the operating pressure is normal pressure, and the temperature at the top of the tower is The temperature at the bottom of the tower is 42°C, and the temperature at the bottom of the tower is 55°C; the outlet pressure of the rich gas compressor is 1.15 MPaG; the hot end outlet temperature of the cooler of the rich gas compressor is 40°C.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the operating pressure of the steam-water separation tank is 1.1 MPaG, and the operating temperature is 40°C; the operation of the rich gas dryer The pressure is 1.05 MPaG, the operating temperature is 40°C; the inlet temperature of the rich gas end of the cold box is 40°C, the outlet temperature is -33°C, the operating pressure of the gas-liquid separation tank is 0.9 MPaG, and the operating temperature is -33°C.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the rough deethanizer has a theoretical plate number of 48, an operating pressure of 0.75 MPaG, and a tower top temperature of -23 The temperature at the bottom of the tower is 18°C; the number of theoretical plates of the propylene rectification tower is 200, the operating pressure is 0.8 MPaG, the temperature at the top of the tower is 15°C, and the temperature at the bottom of the tower is 27°C.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the rich gas composition of the PDH product is: a hydrogen content of 1.57 wt%, a methane content of 0.86 wt%, and an ethylene content of 0.49 wt% , The ethane content is 0.84wt%, the propyne content is 0.01wt%, the propylene content is 32.11wt%, the propane content is 62.65wt%, and the heavy component impurities are 0.95wt%.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the composition of the dry gas produced at the top of the reflux tank at the top of the crude deethanization tower is: a hydrogen content of 24.04wt% and a methane content of 27.34 wt%, ethylene content is 7.5 wt%, ethane content is 12.76 wt%, propylene content is 22.59 wt%, and propane content is 5.77 wt%.
The process method for co-production of a propane dehydrogenation unit and an ethylene unit according to claim 1, wherein the propylene product extracted from the top of the propylene rectification tower has a propylene content of 99.6% by weight and a propane content of 0.4% by weight.
A system for the co-production of a propane dehydrogenation unit and an ethylene unit, used in the process method for the co-production of a propane dehydrogenation unit and an ethylene unit according to any one of claims 1 to 8, characterized in that it comprises:

Oil and gas washing tower, rich gas compressor, rich gas compressor outlet cooler, steam-water separator, rich gas dryer, cold box, gas-liquid separation tank, condensate transfer pump, crude de-ethanizer, crude de-ethanizer Top condenser, top reflux tank of crude de-ethanizer, top reflux pump of crude de-ethanizer, bottom transfer pump of crude de-ethanizer, and propylene distillation tower;

The PDH product rich gas of the propane dehydrogenation reaction unit is connected from the rich gas outlet of the waste heat recovery equipment to the air inlet on the lower side of the oil and gas washing tower through a pipeline, and the washing water is connected to the water inlet on the upper side of the oil and gas washing tower through the pipeline; The gas outlet at the top of the oil-gas washing tower is connected to the inlet of the rich gas compressor through a pipeline, and the outlet of the rich gas compressor is connected to the hot end inlet of the outlet cooler of the rich gas compressor through a pipeline;

The hot end outlet of the rich gas compressor outlet cooler is connected to the inlet of the steam-water separator tank through a pipe, the gas-phase outlet on the top of the steam-water separator tank is connected to the inlet of the rich gas dryer through a pipe, and the outlet of the rich gas dryer is connected to the cold box through a pipe. The inlet of the rich gas end is connected, and the outlet of the rich gas end of the cold box is connected to the inlet of the gas-liquid separator through a pipe;

The gas-phase outlet on the top of the gas-liquid separation tank is connected to the air inlet on the upper part of the crude deethanizer through a pipeline, the liquid phase outlet at the bottom of the gas-liquid separation tank is connected to the inlet of the condensate transfer pump through a pipeline, and the outlet of the condensate transfer pump passes through The pipeline is connected with the liquid inlet in the middle of the crude de-ethanizer;

The gas-phase outlet at the top of the crude de-ethanizer is connected to the hot end inlet of the crude de-ethanizer top condenser through a pipeline, and the hot outlet of the crude de-ethanizer top condenser is connected to the inlet of the crude de-ethanizer top reflux tank;

The gas phase outlet at the top of the crude de-ethanizer reflux tank is connected to the inlet of the fourth stage compressor of the ethylene plant through a pipeline; the liquid phase outlet at the bottom of the crude de-ethanizer reflux tank and the inlet of the reflux pump at the top of the crude de-ethanizer Connect, the outlet of the reflux pump at the top of the crude de-ethanizer is connected to the reflux port at the top of the crude de-ethanizer;

The liquid phase outlet at the bottom of the crude de-ethanizer is connected to the inlet of the crude de-ethanizer bottom transfer pump, and the outlet of the crude de-ethanizer bottom transfer pump is connected to the inlet of the propylene rectification tower;

The propane product outlet at the top of the propylene rectification tower is connected to the inlet of the cryogenic unit through a pipeline, and the propane outlet at the bottom of the propylene rectification tower is connected to the inlet of the reaction unit for propane dehydrogenation.