Ethylene cracking process system

Abstract

The application discloses an ethylene cracking process system, which comprises a cracking unit, a quenching-compression unit and a separation unit, wherein the quenching-compression unit is provided with at least two quenching-compression process sub-lines, at least one device is arranged between the quenching-compression process sub-lines in a cross-line mode, and the device is selected from a pyrolysis diesel stripping tower, a pyrolysis fuel oil stripping tower, a quenching oil viscosity-reducing tower, a process water stripping tower, a pyrolysis gasoline stripping tower and a condensate stripping tower; in addition, the separation unit can be further provided with a debutanizer in a cross-line mode. Through the optimized combination of the devices of various process units, the device setting mode is flexible and various, the product quality is ensured on the basis of reducing the devices, the device operation efficiency is improved, the device maintenance difficulty and the comprehensive energy consumption of the system are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to an ethylene cracking process system, in particular to an ethylene cracking process system capable of improving the operation efficiency of equipment and reducing the energy consumption of the system. BACKGROUND

[0002] The ethylene cracking process system comprises a cracking reaction module and a separation and refining module. In the cracking reaction module, ethane, light hydrocarbon, naphtha, atmospheric diesel, hydrogenated tail oil and other cracking raw materials are mixed with a certain proportion of dilution steam in an ethylene cracking furnace to generate steam thermal cracking reaction to produce ethylene, propylene, butadiene, aromatic hydrocarbon and other basic organic chemical raw materials. Then the above cracking products enter the subsequent separation and refining module, and finally produce polymerization grade ethylene, polymerization grade propylene, mixed carbon four, cracking gasoline and other products through the quenching unit, compression unit and separation unit.

[0003] At present, two or three process production lines need to be set up in large-scale or super-large ethylene cracking devices, but due to the relatively large process system, the operation state of the process equipment and pipelines greatly affects the system capacity and product quality. SUMMARY

[0004] The present application aims to provide an ethylene cracking process system capable of improving the operation efficiency of equipment and reducing the energy consumption of the system to solve the problems of numerous equipment, complex maintenance and high energy consumption in the existing ethylene cracking process system.

[0005] Technical scheme: The ethylene cracking process system of the present application comprises a cracking unit, a quenching-compression unit and a separation unit, wherein the quenching-compression unit is provided with a cracking diesel stripping tower, a cracking fuel oil stripping tower, a quenching oil viscosity reducing tower, a process water stripping tower, a cracking gasoline stripping tower and a condensate stripping tower, the quenching-compression unit is provided with at least two quenching-compression process sub-lines, at least one of the cracking diesel stripping tower, the cracking fuel oil stripping tower, the quenching oil viscosity reducing tower, the process water stripping tower, the cracking gasoline stripping tower and the condensate stripping tower is connected with the quenching-compression process sub-lines in cross-line connection, and further, the feed pipe of the above equipment is connected with the cross-line pipe.

[0006] Specifically, in the quenching unit and compression unit of the large-scale or super-large ethylene device, the tower equipment is optimized and combined, including: (1) the number of large-diameter tower equipment in the quenching oil tower, the quenching water tower, the alkali washing tower and the water washing tower is unchanged; (2) a cross-line pipe is arranged between the two process lines of the quenching unit and the compression unit of the ethylene device; (3) through the cross-line pipe, the small-diameter tower equipment in the cracking diesel stripping tower, the cracking fuel oil stripping tower, the quenching oil viscosity reducing tower, the process water stripping tower, the cracking gasoline stripping tower and the condensate stripping tower is combined and the tower diameter is enlarged.

[0007] More specifically, in order to achieve the coordinated operation of the aforementioned cross-line equipment, according to the process flow, flow detectors and flow regulating valves are respectively installed on the pipelines between the two process sub-lines where cracked diesel is extracted from the middle of the quench oil tower and enters the cracked diesel stripping tower; the pipelines between the bottom of the quench oil tower and enter the cracked fuel oil stripping tower; the pipelines between the bottom of the quench oil tower and enter the quench oil viscosity reducing tower; the pipelines between the bottom of the quench water tower and enter the process water stripping tower; the pipelines between the bottom of the quench water tower and enter the cracked gasoline stripping tower; the pipelines between the bottom of the first line's cracked gas compressor stage 1-3 gas-liquid separator and the second line's cracked gas compressor stage 1-3 gas-liquid separator where cracked gasoline is extracted and enters the cracked gasoline stripping tower; and the pipelines between the bottom of the first line's cracked gas compressor stage 4-5 gas-liquid separator and the second line's cracked gas compressor stage 4-5 gas-liquid separator where condensate is extracted and enters the condensate stripping tower.

[0008] Materials flowing out from different process sub-lines, including quench oil towers, quench water towers, alkali washing towers, water washing towers, pyrolysis gas compressor stage 1-3 gas-liquid separators, and pyrolysis gas compressor stage 4-5 gas-liquid separators, are combined through flow detectors and flow control valves and then enter pyrolysis diesel stripping towers, pyrolysis fuel oil stripping towers, quench oil viscosity reducing towers, process water stripping towers, pyrolysis gasoline stripping towers, and condensate stripping towers for stripping or viscosity reducing component separation. The outflowing materials are no longer split.

[0009] Meanwhile, the equipment was also adjusted accordingly. The diameters of the cross-line cracked diesel stripping tower, cracked fuel oil stripping tower, quench oil viscosity reducing tower, process water stripping tower, cracked gasoline stripping tower, and condensate stripping tower were enlarged, while the head of the corresponding material conveying pumps remained unchanged, the flow rate was increased, the power of the matching motors was also increased, and the pump efficiency was improved.

[0010] On the other hand, from the perspective of the separation unit, the separation unit is provided with at least two separation process sub-lines, and the butane removal tower is connected to the separation process sub-lines across the line; furthermore, the feed pipeline of the butane removal tower is connected to the cross-line pipeline. The separation process sub-lines are at least one of the following: sequential separation process sub-line, pre-ethane removal separation process sub-line, pre-propane removal separation process sub-line, progressive separation process sub-line, and oil absorption separation process sub-line.

[0011] Specifically, in the separation unit of a large-scale or ultra-large-scale ethylene cracking unit, the tower equipment is optimized and combined, including: (1) keeping the number of ethylene distillation towers, propylene distillation towers and other large-diameter tower equipment unchanged; (2) setting up cross-line pipelines between the two process lines of the ethylene unit separation unit; (3) merging the butane de-butane tower and other small-diameter tower equipment and enlarging the tower diameter through the cross-line pipelines according to different separation processes.

[0012] More specifically, when the separate sub-lines select different process modes, the cross-line equipment is set as follows:

[0013] The separate process sub-lines are all sequential separation process sub-lines, and at least one of a deethanizer, a C2 green oil absorption tower, a depropanizer, a methane stripping tower and a debutanizer is arranged across the lines between the sequential separation process sub-lines.

[0014] The separate process sub-lines are all pre-deethanization process sub-lines, and at least one of a C2 green oil absorption tower, a demethanizer, a depropanizer and a debutanizer is arranged across the lines between the pre-deethanization process sub-lines.

[0015] The separate process sub-lines are all pre-depropanization process sub-lines, and at least one of a pre-demethanizer, a demethanizer, a deethanizer and a debutanizer is arranged across the lines between the pre-depropanization process sub-lines.

[0016] The separate process sub-lines are all gradual separation process sub-lines, and at least one of a pre-demethanizer, a demethanizer, a deethanizer and a debutanizer is arranged across the lines between the gradual separation process sub-lines.

[0017] The separate process sub-lines are all oil absorption separation process sub-lines, and at least one of a deethanizer and a debutanizer is arranged across the lines between the oil absorption separation process sub-lines.

[0018] The separate process sub-lines are different separation process sub-lines, and a debutanizer is arranged across the lines between the process sub-lines.

[0019] In order to realize the cooperative operation of the cross-line equipment, a flow detector and a flow regulating valve are arranged on the equipment cross-line pipeline. More specifically, the materials flowing out of the two process lines through the flow detector and the flow regulating valve are combined and then enter the cross-line equipment for rectification and separation, part of the materials is not split, and the other part of the materials is still split, and then the materials are returned to the two process lines through the flow detector and the flow regulating valve, respectively.

[0020] Meanwhile, the equipment is also improved, the diameter of the tower of the cross-line equipment is enlarged, the corresponding material conveying pump has unchanged lift, increased flow and increased motor power, and the voltage grade of the matching power equipment is correspondingly improved.

[0021] Beneficial effects: Compared with the prior art, the present application has the following remarkable advantages:

[0022] (1) By optimizing the combination of each process unit equipment, the equipment setting mode is flexible and diverse, the product quality is ensured on the basis of reducing the equipment, the equipment operation efficiency is improved, the equipment maintenance difficulty and the system comprehensive energy consumption are reduced;

[0023] (2) After optimization of the quench-compression unit, the equipment is reduced by more than 20%, and the material conveying efficiency is increased to more than 75%;

[0024] (3) After the separation unit is optimized, the equipment is reduced by more than 30%, the product purity reaches more than 99 mol%, the material conveying voltage level is greatly improved, and cable loss is reduced. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the rapid cooling-compression unit structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the separation unit structure of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0028] Example 1: Quenching-Compression Unit of Ethylene Cracking Process System

[0029] like Figure 1 As shown, the quench-compression unit has two quench-compression process sub-lines. The first quench-compression process sub-line includes a quench oil tower A1, a quench water tower A2, a pyrolysis gas compressor (stages 1-3) A3, an alkaline washing tower A4, a water washing tower A5, a pyrolysis gas compressor (stages 4-5) A6, and a pyrolysis gas dryer A7. The second quench-compression process sub-line includes a quench oil tower B1, a quench water tower B2, a pyrolysis gas compressor (stages 1-3) B3, an alkaline washing tower B4, a water washing tower B5, a pyrolysis gas compressor (stages 4-5) B6, and a pyrolysis gas dryer B7. A pyrolysis diesel stripping tower C1, a pyrolysis fuel oil stripping tower C2, a quench oil viscosity reducing tower C3, a process water stripping tower C4, a pyrolysis gasoline stripping tower C5, and a condensate stripping tower C6 are installed across the two quench-compression process sub-lines. The pipeline between the middle sections of quench oil towers A1 and B1, from which cracked diesel oil is drawn, enters the cracked diesel stripping tower C1; the pipeline between the bottom sections of quench oil towers A1 and B1, from which cracked fuel oil is drawn, enters the cracked fuel oil stripping tower C2; the pipeline between the bottom sections of quench oil towers A1 and B1, from which quench oil is drawn, enters the quench oil viscosity reducing tower C3; the pipeline between the bottom sections of quench water towers A2 and B2, from which process water is drawn, enters the process water stripping tower C4; and the pipeline between the bottom sections of quench water towers A2 and B2, from which cracked gasoline is drawn, enters the cracked gasoline... Flow detectors and flow regulating valves are installed on the pipelines between the stripping towers C5 and C5, on the pipelines between the bottom of the A3 gas-liquid separator of the first-line cracked gas compressor (stages 1-3) and the bottom of the B3 gas-liquid separator of the second-line cracked gas compressor (stages 1-3) where cracked gasoline is extracted and enters the cracked gasoline stripping tower C5, and on the pipelines between the bottom of the A6 gas-liquid separator of the first-line cracked gas compressor (stages 4-5) and the bottom of the B6 gas-liquid separator of the second-line cracked gas compressor (stages 4-5) where condensate is extracted and enters the condensate stripping tower C6.

[0030] The working principle of the above quenching-compression unit is as follows:

[0031] Taking atmospheric diesel AGO as a cracking raw material, cracking gas P1 from outside in the first quenching-compression process sub-line enters quenching oil tower A1, quenching water tower A2, cracking gas compressor 1-3 stage A3, caustic washing tower A4, water washing tower A5, cracking gas compressor 4-5 stage A6, cracking gas dryer A7 in turn to separate cracking gasoline, cracking diesel, cracking fuel oil and cracking gas, pressurize, remove acidic gas and remove water. The cracking gas 108 flowing out of the cracking gas dryer A7 is sent out of the outside.

[0032] Cracking gas P2 from outside in the second quenching-compression process sub-line enters quenching oil tower B1, quenching water tower B2, cracking gas compressor 1-3 stage B3, caustic washing tower B4, water washing tower B5, cracking gas compressor 4-5 stage B6, cracking gas dryer B7 in turn to separate cracking gasoline, cracking diesel, cracking fuel oil and cracking gas, pressurize, remove acidic gas and remove water. The cracking gas 208 flowing out of the cracking gas dryer B7 is sent out of the outside.

[0033] Among them, the materials flowing out of the quenching oil tower, quenching water tower, caustic washing tower, water washing tower, cracking gas compressor 1-3 stage gas-liquid separator and cracking gas compressor 4-5 stage gas-liquid separator in the two quenching-compression process sub-lines are combined through flow detectors and flow regulating valves to enter cracking diesel stripping tower, cracking fuel oil stripping tower, quenching oil viscosity reducing tower, process water stripping tower, cracking gasoline stripping tower and condensate stripping tower for stripping or viscosity reduction. After separation, the materials flowing out are no longer divided. More specifically, part of the cracking diesel is drawn out from the quenching oil tower A1 and B1 respectively to enter the cracking diesel stripping tower C1 for stripping treatment. Part of the cracking fuel oil is drawn out from the bottom of the quenching oil tower A1 and B1 respectively to enter the cracking fuel oil stripping tower C2 for stripping treatment. Part of the quenching oil is drawn out from the bottom of the quenching oil tower A1 and B1 respectively to enter the quenching oil viscosity reducing tower C3 for viscosity reduction treatment. Part of the process water is drawn out from the bottom of the quenching water tower A2 and B2 respectively to enter the process water stripping tower C4 for stripping treatment. Part of the cracking gasoline is drawn out from the bottom of the quenching water tower A2 and B2 and the gas-liquid separator of the cracking gas compressor 1-3 stage A3 and B3 respectively to enter the cracking gasoline stripping tower C5 for stripping treatment. Part of the condensate is drawn out from the gas-liquid separator of the cracking gas compressor 4-5 stage A6 and B6 respectively to enter the condensate stripping tower C6 for stripping treatment.

[0034] The running equipment of the above quenching-compression unit is as follows:

[0035] The cracking raw material is one or a combination of one or more of ethane C2, light hydrocarbon LPG, naphtha NAP, atmospheric diesel AGO and hydrogenated tail oil HGO.

[0036] When the cracking feedstock is ethane C2, according to the requirements of the process materials, it is necessary to set up a quench oil tower, a quench water tower, an alkali washing tower, a water washing tower, a quench oil viscosity reducing tower, a process water stripping tower, a cracked gasoline stripping tower, and a condensate stripping tower.

[0037] When the cracking feedstock is light hydrocarbon LPG, according to the requirements of the process materials, it is necessary to set up a quench oil tower, a quench water tower, an alkali washing tower, a water washing tower, a quench oil viscosity reducing tower, a process water stripping tower, a cracked gasoline stripping tower, and a condensate stripping tower.

[0038] When the cracking feedstock is naphtha (NAP), according to the requirements of the process materials, it is necessary to set up a quench oil tower, a quench water tower, an alkaline washing tower, a water washing tower, a cracked fuel oil stripping tower, a quench oil viscosity reduction tower, a process water stripping tower, a cracked gasoline stripping tower, and a condensate stripping tower.

[0039] When the cracking feedstock is atmospheric diesel (AGO), according to the requirements of the process materials, it is necessary to set up a quench oil tower, a quench water tower, an alkaline washing tower, a water washing tower, a cracked diesel stripping tower, a cracked fuel oil stripping tower, a quench oil viscosity reducing tower, a process water stripping tower, a cracked gasoline stripping tower, and a condensate stripping tower.

[0040] When the cracking feedstock is hydrotreated tail oil (HGO), depending on the requirements of the process materials, it is necessary to set up a quench oil tower, a quench water tower, an alkali washing tower, a water washing tower, a cracked diesel stripping tower, a cracked fuel oil stripping tower, a quench oil viscosity reducing tower, a process water stripping tower, a cracked gasoline stripping tower, and a condensate stripping tower.

[0041] Example 2: Separation Unit of Ethylene Cracking Process System

[0042] like Figure 2 As shown, the separation unit has two sequential separation process sub-lines. The first sequential separation process sub-line is equipped with a demethanizer A11, an ethylene distillation column A21, and a propylene distillation column A31. The second sequential separation process sub-line is equipped with a demethanizer B11, an ethylene distillation column B21, and a propylene distillation column B31. An ethylene deethaner C11, a C2 green oil absorber C21, a propane deethaner C31, a methane stripping column C41, and a butane deethaner C51 are installed across the two sequential separation process sub-lines. Flow detectors and flow regulating valves are installed on the cross-line pipelines.

[0043] The working principle of the above separation unit is as follows:

[0044] The cracked gas 108, 208 from outside the boundary after compression, desulfurization, drying and deep cooling is separated by rectification in the demethanizing columns A11, B11, respectively, and the hydrogen and methane at the top of the demethanizing columns A11, B11 are sent out of the boundary, respectively. The material at the bottom of the demethanizing columns A11, B11 is separated by rectification in the deethanizing column C11, carbon dioxide green oil absorption column C21, ethylene rectification column A21, B21, and the polymerization grade ethylene product 109, 209 at the top of the ethylene rectification column A21, B21 is sent out of the boundary, respectively. The material at the bottom of the deethanizing column A21, B21 is separated by rectification in the depropanizing column C31, methane stripping column C41, propylene rectification column A31, B31, and the polymerization grade propylene product 110, 210 at the top of the propylene rectification column A31, B31 is sent out of the boundary, respectively. The material at the bottom of the depropanizing column C31 is separated by rectification in the debutanizing column C51, and the mixed carbon four at the top of the debutanizing column C51 is sent out of the boundary, and the cracked gasoline at the bottom of the debutanizing column C51 is sent out of the boundary. The material at the bottom of the demethanizing column A11, B11 is combined through a flow detector and a flow regulating valve and then enters the deethanizing column C11 for separation, and the material at the top of the deethanizing column C11 is combined and then enters the carbon dioxide green oil absorption column C21 for separation, and the material at the top of the carbon dioxide green oil absorption column C21 is divided into streams through a flow detector and a flow regulating valve and then returned to the respective sequential separation process sub-lines.

[0045] The above separation unit operating equipment is as follows:

[0046] The sequential separation process flow is provided with eight tower devices of demethanizing column, deethanizing column, carbon dioxide green oil absorption column, ethylene rectification column, depropanizing column, methane stripping column, propylene rectification column and debutanizing column.

[0047] Comparative Example 1

[0048] In the existing technology of preparing ethylene product by steam thermal cracking, the ethylene device quenching unit and compression unit have two process production lines of A line and B line with a production scale of 2 million tons / year, and the cracking raw material is naphtha NAP, and the tower devices are provided as follows:

[0049] Line A Line B Column equipment name Equipment number Column equipment name Equipment number Quench oil column 1 Quench oil column 1 Quench water column 1 Quench water column 1 Caustic wash column 1 Caustic wash column 1 Water wash column 1 Water wash column 1 Cracked fuel oil stripping column 1 Cracked fuel oil stripping column 1 Quench oil viscosity reduction column 1 Quench oil viscosity reduction column 1 Process water stripping column 1 Process water stripping column 1 Cracked gasoline stripping column 1 Cracked gasoline stripping column 1 Condensate stripping column 1 Condensate stripping column 1

[0050] The total number of towers is 18, and there are problems of large number of equipment and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small diameter tower device is 51.0%.

[0051] Example 3

[0052] The production scale is two process production lines of A line and B line with a production scale of 2 million tons / year, and the cracking raw material is naphtha NAP, and the tower devices are optimized and combined, the number of large diameter tower devices is kept unchanged, a cross-line pipe is arranged between the A line and the B line, the two small diameter tower devices are combined into one through the cross-line pipe, the tower diameter is enlarged, and the number is reduced by half, and the tower devices are provided as follows:

[0053] Line A Line B Line A and Line B combined Column equipment name Number Column equipment name Number Column equipment name Number Quench oil column 1 Quench oil column 1 Cracked fuel oil stripping column 1 Quench water column 1 Quench water column 1 Quench oil viscosity reduction column 1 Caustic wash column 1 Caustic wash column 1 Process water stripping column 1 Water wash column 1 Water wash column 1 Cracked gasoline stripping column 1 Condensate stripping column 1

[0054] The total number of columns is 13, thereby the number of column devices is reduced from 18 in the prior art to 13 in the present application, with a reduction rate of 27.78%, and the pump efficiency of the material conveying pump corresponding to the large-diameter column device is increased to 67.0% after two-in-one.

[0055] Comparative Example 2

[0056] In the quenching unit and compression unit of an ethylene plant for preparing ethylene products by steam thermal cracking in the prior art, the production scale is two process production lines of 2.4 million tons / year A line and B line, the cracking raw material is atmospheric gas oil AGO, and the column devices are set as follows:

[0057] Line A Line B Column equipment name Equipment number Column equipment name Equipment number Quench oil column 1 Quench oil column 1 Quench water column 1 Quench water column 1 Caustic wash column 1 Caustic wash column 1 Water wash column 1 Water wash column 1 Cracked diesel stripping column 1 Cracked diesel stripping column 1 Cracked fuel oil stripping column 1 Cracked fuel oil stripping column 1 Quench oil viscosity reduction column 1 Quench oil viscosity reduction column 1 Process water stripping column 1 Process water stripping column 1 Cracked gasoline stripping column 1 Cracked gasoline stripping column 1 Condensate stripping column 1 Condensate stripping column 1

[0058] The total number of columns is 20, there are problems of too many devices and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter column device is 53.4%.

[0059] Example 4

[0060] The production scale is two process production lines of 2.4 million tons / year A line and B line, the cracking raw material is atmospheric gas oil AGO, the column devices are optimized and combined, the number of large-diameter column devices is kept unchanged, a cross-line pipe is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipe, the column diameter is enlarged, and the number is reduced by half, and the column devices are set as follows:

[0061] Line A Line B Column equipment name Equipment number Column equipment name Equipment number Quench oil column Quench oil column Quench water column Quench water column 1 Caustic wash column 1 Caustic wash column 1 Water wash column 1 Water wash column 1 Cracked diesel stripping column 1 Cracked diesel stripping column 1 Cracked fuel oil stripping column 1 Cracked fuel oil stripping column 1 Quench oil viscosity reduction column 1 Quench oil viscosity reduction column 1 Process water stripping column 1 Process water stripping column 1 Cracked gasoline stripping column 1

[0062] The total number of columns is 14, thereby the number of column devices is reduced from 20 in the prior art to 14 in the present application, with a reduction rate of 30.00%, and the pump efficiency of the material conveying pump corresponding to the large-diameter column device is increased to 69.5% after two-in-one.

[0063] Comparative Example 3

[0064] In the quenching unit and compression unit of an ethylene plant for preparing ethylene products by steam thermal cracking in the prior art, the production scale is two process production lines of 3 million tons / year A line and B line, the cracking raw material is hydrogenated tail oil HGO, and the column devices are set as follows:

[0065] Cracked gasoline stripping column Condensate stripping column Condensate stripping column Line A Line B Line A and Line B combined Column equipment name 1 Number 1 Column equipment name 1 Number 1 Column equipment name 1 Number 1 Quench oil column 1 Quench oil column 1 Cracked diesel stripping column 1 Quench water column 1 Quench water column 1 Cracked fuel oil stripping column 1 Caustic wash column 1 Caustic wash column 1 Quench oil viscosity reduction column 1 Water wash column 1 Water wash column 1 Process water stripping column 1 Cracked gasoline stripping column 1 Condensate stripping column 1

[0066] The total number of columns is 20, there are problems of too many devices and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter column device is 56.0%.

[0067] Example 5

[0068] The production scale is 3 million tons / year of two process production lines of A line and B line, the cracking raw material is hydrogenated tail oil HGO, the tower equipment is optimally combined, the number of large diameter tower equipment is kept unchanged, the cross-line pipe is arranged between the A line and the B line, the small diameter tower equipment is combined into two, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0069] Line A Line B Column equipment name Equipment number Column equipment name Equipment number Quench oil column Quench oil column Quench water column Quench water column 1 Caustic wash column 1 Caustic wash column 1 Water wash column 1 Water wash column 1 Quench oil viscosity reduction column 1 Quench oil viscosity reduction column 1 Process water stripping column 1 Process water stripping column 1 Cracked gasoline stripping column 1 Cracked gasoline stripping column 1 Condensate stripping column 1 Condensate stripping column 1 Line A 1

[0070] The total number of towers is 14, thereby the number of tower equipment is reduced from 20 in the prior art to 14 in the present application, the reduction rate is 30.00%, and the pump efficiency of the material conveying pump corresponding to the combined large diameter tower equipment is increased to 72.8%.

[0071] Comparative Example 4

[0072] In the quenching unit and compression unit of the ethylene device for preparing ethylene product by steam thermal cracking in the prior art, the production scale is 3.2 million tons / year of two process production lines of A line and B line, the cracking raw material is light hydrocarbon LPG, and the tower equipment is arranged as follows:

[0073] Line B Line A and Line B combined Column equipment name Number Column equipment name Number Column equipment name 1 Number 1 Quench oil column 1 Quench oil column 1 Quench oil viscosity reduction column 1 Quench water column 1 Quench water column 1 Process water stripping column 1 Caustic wash column 1 Caustic wash column 1 Cracked gasoline stripping column 1 Water wash column 1 Water wash column 1 Condensate stripping column 1 Line A 1 Line B 1

[0074] The total number of towers is 16, there are problems of too many equipment and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small diameter tower equipment is 57.2%.

[0075] Example 6

[0076] The production scale is 3.2 million tons / year of two process production lines of A line and B line, the cracking raw material is light hydrocarbon LPG, the tower equipment is optimally combined, the number of large diameter tower equipment is kept unchanged, the cross-line pipe is arranged between the A line and the B line, the small diameter tower equipment is combined into two, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0077] Line A and Line B combined Column equipment name Number Column equipment name Number Column equipment name Number Quench oil column Quench oil column Quench oil viscosity reduction column 1 Quench water column 1 Quench water column 1 Process water stripping column 1 Caustic wash column 1 Caustic wash column 1 Cracked gasoline stripping column 1 Water wash column 1 Water wash column 1 Condensate stripping column 1 Line A 1 Line B 1

[0078] The total number of towers is 12, thereby the number of tower equipment is reduced from 16 in the prior art to 12 in the present application, the reduction rate is 25.00%, and the pump efficiency of the material conveying pump corresponding to the combined large diameter tower equipment is increased to 74.5%.

[0079] Comparative Example 5

[0080] In the quenching unit and compression unit of the ethylene device for preparing ethylene product by steam thermal cracking in the prior art, the production scale is 3.6 million tons / year of two process production lines of A line and B line, the cracking raw material is ethane C2, and the tower equipment is arranged as follows:

[0081]

[0082]

[0083] The total number of towers is 16, and there are problems of large number of equipment and high engineering cost. The pump efficiency of the material conveying pump corresponding to the small-diameter tower equipment is 59.0%.

[0084] Example 7

[0085] The production scale is two process production lines of 3.6 million tons / year of A line and B line, the cracking raw material is ethane C2, the tower equipment is optimized and combined, the number of large-diameter tower equipment is kept unchanged, a cross-line pipe is arranged between the A line and the B line, the small-diameter tower equipment is combined into one, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0086] Column equipment name Equipment number Column equipment name Equipment number Quench oil column Quench oil column Quench water column Quench water column Caustic wash column ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1

[0087] The total number of towers is 12, and thus the number of tower equipment is reduced from 16 of the prior art to 12 of the present application, with a reduction rate of 25.00%, and the pump efficiency of the material conveying pump corresponding to the large-diameter tower equipment is increased to 77.0%.

[0088] Comparative Example 6

[0089] In the quenching unit and compression unit of the ethylene device for preparing ethylene product by steam thermal cracking in the prior art, the production scale is two process production lines of 3 million tons / year of A line and B line, the cracking raw material of the A line is ethane C2, the cracking raw material of the B line is naphtha NAP, and the tower equipment is arranged as follows:

[0090] ​ ​ ​ ​ ​ ​ ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 caustic wash column 1 water wash column 1 water wash column 1 quench oil visbreaking column 1 cracked fuel oil stripping column 1 process water stripping column 1 quench oil visbreaking column 1 cracked gasoline stripping column 1 process water stripping column 1 condensate stripping column 1 cracked gasoline stripping column 1 condensate stripping column 1

[0091] The total number of towers is 17, and there are problems of large number of equipment and high engineering cost. The pump efficiency of the material conveying pump corresponding to the small-diameter tower equipment is 55.3%.

[0092] Example 8

[0093] The production scale is two process production lines of 3 million tons / year of A line and B line, the cracking raw material of the A line is ethane C2, the cracking raw material of the B line is naphtha NAP, the tower equipment is optimized and combined, the number of large-diameter tower equipment is kept unchanged, a cross-line pipe is arranged between the A line and the B line, the small-diameter tower equipment is combined into one, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0094] line a line b line a and line b combined column equipment name quantity column equipment name quantity column equipment name quantity quench oil column 1 quench oil column 1 cracked fuel oil stripping column 1 quench water column 1 quench water column 1 quench oil visbreaking column 1 caustic wash column 1 caustic wash column 1 process water stripping column 1 water wash column 1 water wash column 1 cracked gasoline stripping column 1 condensate stripping column 1

[0095] The total number of towers is 13, thus the number of tower equipment is reduced from 17 in the prior art to 13 in the present application, with a reduction rate of 23.53%, and the pump efficiency of the material conveying pump corresponding to the large-diameter tower equipment is increased to 71.8% after two-in-one.

[0096] Comparative Example 7

[0097] In the quenching unit and compression unit of the ethylene plant for preparing ethylene products by steam thermal cracking in the prior art, the production scale is two process production lines of 3 million tons / year of A line and B line, the cracking raw material of the A line is light hydrocarbon LPG, and the cracking raw material of the B line is hydrogenated tail oil HGO, and the tower equipment is set as follows:

[0098] line a line b column equipment name equipment quantity column equipment name equipment quantity quench oil column 1 quench oil column 1 quench water column 1 quench water column 1 caustic wash column 1 caustic wash column 1 water wash column 1 water wash column 1 quench oil visbreaking column 1 cracked diesel stripping column 1 process water stripping column 1 cracked fuel oil stripping column 1 cracked gasoline stripping column 1 quench oil visbreaking column 1 condensate stripping column 1 process water stripping column 1 cracked gasoline stripping column 1 condensate stripping column 1

[0099] The total number of towers is 18, which has the problems of large number of equipment and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter tower equipment is 55.5%.

[0100] Example 9

[0101] The production scale is two process production lines of 3 million tons / year of A line and B line, the cracking raw material of the A line is light hydrocarbon LPG, and the cracking raw material of the B line is hydrogenated tail oil HGO, the tower equipment is optimized and combined, the number of large-diameter tower equipment is kept unchanged, a cross-line pipe is arranged between the A line and the B line, the small-diameter tower equipment is combined into two, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is set as follows:

[0102]

[0103]

[0104] The total number of towers is 14, thus the number of tower equipment is reduced from 18 in the prior art to 14 in the present application, with a reduction rate of 22.22%, and the pump efficiency of the material conveying pump corresponding to the large-diameter tower equipment is increased to 72.0% after two-in-one.

[0105] Comparative Example 8

[0106] In the quenching unit and compression unit of the ethylene plant for preparing ethylene products by steam thermal cracking in the prior art, the production scale is two process production lines of 3 million tons / year of A line and B line, the cracking raw material of the A line is naphtha NAP, and the cracking raw material of the B line is atmospheric gas oil AGO, and the tower equipment is set as follows:

[0107] line a line b column equipment name equipment quantity column equipment name equipment quantity quench oil column 1 quench oil column 1 quench water column 1 quench water column 1 caustic wash column 1 caustic wash column 1 water wash column 1 water wash column 1 cracked fuel oil stripping column 1 cracked diesel stripping column 1 quench oil visbreaking column 1 cracked fuel oil stripping column 1 process water stripping column 1 quench oil visbreaking column 1 cracked gasoline stripping column 1 process water stripping column 1 cracked gasoline stripping column 1 condensate stripping column 1 line a 1

[0108] The total number of towers is 19, which has the problems of large number of equipment and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter tower equipment is 55.7%.

[0109] Example 10

[0110] The production scale is 3 million tons / year of two process production lines of A line and B line, the cracking raw material of A line is naphtha NAP, the cracking raw material of B line is atmospheric gas oil AGO, the column equipment is optimized and combined, the number of large-diameter column equipment is kept unchanged, a cross-line pipe is arranged between A line and B line, small-diameter column equipment is combined into one, the column diameter is enlarged, and the number is reduced by half, and the column equipment is arranged as follows:

[0111] line b line a and line b combined column equipment name quantity column equipment name quantity column equipment name quantity quench oil column quench oil column 1 cracked diesel stripping column 1 quench water column 1 quench water column 1 cracked fuel oil stripping column 1 caustic wash column 1 caustic wash column 1 quench oil visbreaking column 1 water wash column 1 water wash column 1 process water stripping column 1 cracked gasoline stripping column 1 condensate stripping column 1 line a 1

[0112] The total number of columns is 14, thereby the number of column equipment is reduced from 19 in the prior art to 14 in the present application, the reduction rate is 26.32%, and the pump efficiency of the material conveying pump corresponding to the combined large-diameter column equipment is increased to 72.3%.

[0113] Comparative Example 9

[0114] In the quenching unit and compression unit of the ethylene device for preparing ethylene product by steam thermal cracking in the prior art, the production scale is 3 million tons / year of two process production lines of A line and B line, the cracking raw material of A line is ethane C2, the cracking raw material of B line is light hydrocarbon LPG, and the column equipment is arranged as follows:

[0115] line b line a and line b combined column equipment name quantity column equipment name quantity column equipment name 1 quantity 1 quench oil column 1 quench oil column 1 quench oil visbreaking column 1 quench water column 1 quench water column 1 process water stripping column 1 caustic wash column 1 caustic wash column 1 cracked gasoline stripping column 1 water wash column 1 water wash column 1 condensate stripping column 1 line a 1 line b 1

[0116] The total number of columns is 16, there are problems of too many equipment and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter column equipment is 55.0%.

[0117] Example 11

[0118] The production scale is 3 million tons / year of two process production lines of A line and B line, the cracking raw material of A line is ethane C2, the cracking raw material of B line is light hydrocarbon LPG, the column equipment is optimized and combined, the number of large-diameter column equipment is kept unchanged, a cross-line pipe is arranged between A line and B line, small-diameter column equipment is combined into one, the column diameter is enlarged, and the number is reduced by half, and the column equipment is arranged as follows:

[0119] line a and line b combined column equipment name quantity column equipment name quantity column equipment name quantity quench oil column quench oil column cracked diesel stripping column 1 quench water column 1 quench water column 1 cracked fuel oil stripping column 1 caustic wash column 1 caustic wash column 1 quench oil visbreaking column 1 water wash column 1 water wash column 1 process water stripping column 1 cracked gasoline stripping column 1 condensate stripping column 1

[0120] The total number of columns is 12, thereby the number of column equipment is reduced from 16 in the prior art to 12 in the present application, the reduction rate is 25.00%, and the pump efficiency of the material conveying pump corresponding to the combined large-diameter column equipment is increased to 71.6%.

[0121] Comparative Example 10

[0122] In the quenching unit and compression unit of the ethylene plant for preparing ethylene product by steam thermal cracking in the prior art, the production scale is two process production lines of 3 million tons / year A line and B line, the cracking raw material of the A line is atmospheric gas oil AGO, and the cracking raw material of the B line is hydrogenated tail oil HGO, and the tower device is set as follows:

[0123]

[0124]

[0125] The total number of towers is 20, and there are problems of large number of devices and high engineering cost, and the pump efficiency of the material conveying pump corresponding to the small-diameter tower device is 55.8%.

[0126] Example 12

[0127] The production scale is two process production lines of 3 million tons / year A line and B line, the cracking raw material of the A line is atmospheric gas oil AGO, and the cracking raw material of the B line is hydrogenated tail oil HGO, the tower device is optimized and combined, the number of large-diameter tower devices is unchanged, a cross-line pipe is arranged between the A line and the B line, the small-diameter tower device is combined into one, the tower diameter is enlarged, and the number is reduced by half, and the tower device is set as follows:

[0128] line a line b column equipment name equipment quantity column equipment name equipment quantity demethanizer demethanizer deethanizer deethanizer 1 carbon dioxide green oil absorption column 1 carbon dioxide green oil absorption column 1 ethylene rectification column 1 ethylene rectification column 1 depropanizer 1 depropanizer 1 methane stripping column 1 methane stripping column 1 propylene rectification column 1 propylene rectification column 1 debutanizer 1 debutanizer 1 line a 1

[0129] The total number of towers is 14, so the number of tower devices is reduced from 20 in the prior art to 14 in the present application, the reduction rate is 30.00%, the combined one becomes a large-diameter tower device, and the pump efficiency of the material conveying pump corresponding to the combined one is increased to 72.5%.

[0130] Comparative Example 11

[0131] In the separation unit of the ethylene cracking plant with a production scale of 2 million tons / year in the prior art, the A production line and the B production line adopt a sequential separation process, and the tower device is set as follows:

[0132] line b line a and line b combined column equipment name quantity column equipment name quantity column equipment name 1 quantity 1 demethanizer 1 demethanizer 1 deethanizer 1 ethylene rectification column 1 ethylene rectification column 1 carbon dioxide green oil absorption column 1 propylene rectification column 1 propylene rectification column 1 depropanizer 1 methane stripping column 1 debutanizer 1 line a 1 line b 1 column equipment name 1

[0133] The total number of tower devices is 16, there are problems of large number of devices and high engineering cost, and the voltage level of the motor device matched with the small-diameter tower device corresponding to the material conveying pump is 380V according to the design specification, and the cable loss of the power transmission is large.

[0134] Example 13

[0135] The present embodiment relates to a method for optimizing a combined separation unit of an ethylene plant, with a production scale of 2 million tons / year of two process production lines of A line and B line, using a sequential separation process, optimizing and combining the column devices, keeping the number of large-diameter column devices unchanged, setting a cross-line pipeline between the A line and the B line, combining two small-diameter column devices into one through the cross-line pipeline, enlarging the column diameter, and reducing the number by half, and setting the column devices as follows:

[0136] equipment quantity column equipment name equipment quantity ​ ​ ​ ​ ​ ​ ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1 ​ 1

[0137] The total number of column devices is 11, thus the number of column devices is reduced from 16 in the prior art to 11 in the present application, with a reduction rate of 31.25%, after combining two small-diameter column devices into one and enlarging the column diameter, the corresponding material conveying pump motor power is doubled, the matching voltage level is increased to 6000V according to the design specification, the cable loss of power transmission can be reduced by 0.07%, and the energy consumption is also reduced accordingly, finally obtaining 99.95 mol% of polyethylene product and 99.6 mol% of polypropylene product.

[0138] Comparative Example 12

[0139] In the prior art separation unit of an ethylene cracking plant with a production scale of 2.4 million tons / year, the A production line and the B production line use a front deethanization separation process, and the column devices are set as follows:

[0140] ​ ​ ​ ​ ​ ​ Deethanizer 1 Deethanizer 1 Carbon dioxide absorber 1 Carbon dioxide absorber 1 Demethanizer 1 Demethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 Depropanizer 1 Depropanizer 1 Propylene rectifier 1 Propylene rectifier 1 Debutanizer 1 Debutanizer 1

[0141] The total number of column devices is 14, which has the problems of large number of devices and high engineering cost, and the voltage level of the motor device matched with the small-diameter column device corresponding to the material conveying pump is 380V according to the design specification, and the cable loss of power transmission is large.

[0142] Example 14

[0143] The production scale is 2.4 million tons / year of two process production lines of A line and B line, using a front deethanization separation process, optimizing and combining the column devices, keeping the number of large-diameter column devices unchanged, setting a cross-line pipeline between the A line and the B line, combining two small-diameter column devices into one through the cross-line pipeline, enlarging the column diameter, and reducing the number by half, and setting the column devices as follows:

[0144] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number Deethanizer 1 Deethanizer 1 Carbon dioxide absorber 1 Ethylene rectifier 1 Ethylene rectifier 1 Demethanizer 1 Propylene rectifier 1 Propylene rectifier 1 Depropanizer 1 Debutanizer 1

[0145] The total number of column devices is 10, thereby the number of column devices is reduced from 14 in the prior art to 10 in the present application, the reduction rate is 28.57%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 6000V according to the design specification, the cable loss of the power transmission can be reduced by 0.08%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

[0146] Comparative Example 13

[0147] In the prior art separation unit of an ethylene cracking device with a production scale of 3 million tons / year, the A production line and the B production line adopt a front depropanization separation process, and the column devices are set as follows:

[0148] A line B line Tower equipment name Equipment number Tower equipment name Equipment number High pressure depropanizer 1 High pressure depropanizer 1 Low pressure depropanizer 1 Low pressure depropanizer 1 Pre-demethanizer 1 Pre-demethanizer 1 Demethanizer 1 Demethanizer 1 Deethanizer 1 Deethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 Propylene rectifier 1 Propylene rectifier 1 Debutanizer 1 Debutanizer 1

[0149] The total number of column devices is 16, there are problems of too many devices and high engineering cost, and the voltage level of the motor device supporting the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0150] Example 15

[0151] The production scale of the A line and the B line is 3 million tons / year, a front depropanization separation process is adopted, the column devices are optimally combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipeline, the column diameter is enlarged, and the number is reduced by half, and the column devices are set as follows:

[0152] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number High pressure depropanizer 1 High pressure depropanizer 1 Pre-demethanizer 1 Low pressure depropanizer 1 Low pressure depropanizer 1 Demethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 Deethanizer 1 Propylene rectifier 1 Propylene rectifier 1 Debutanizer 1

[0153] The total number of column devices is 12, thereby the number of column devices is reduced from 16 in the prior art to 12 in the present application, the reduction rate is 25.00%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 6000V according to the design specification, the cable loss of the power transmission can be reduced by 0.09%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

[0154] Comparative Example 14

[0155] In the prior art separation unit of an ethylene cracking device with a production scale of 3.2 million tons / year, the A production line and the B production line adopt a gradual separation process, and the column devices are set as follows:

[0156] A line B line Tower equipment name Equipment number Tower equipment name Equipment number 1# Demethanizer 1 1# Demethanizer 1 2# Demethanizer 1 2# Demethanizer 1 1# Deethanizer 1 1# Deethanizer 1 2# Deethanizer 1 2# Deethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 1# Depropanizer 1 1# Depropanizer 1 2# Depropanizer 1 2# Depropanizer 1 Propylene rectifier 1 Propylene rectifier 1 Debutanizer 1 Debutanizer 1

[0157] The total number of column devices is 18, and there are problems of large number of devices and high engineering cost. The voltage level of the motor device matched with the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0158] Example 16

[0159] The production scale is 3.2 million tons / year of two process production lines of A line and B line, and the gradual separation process is used. The column devices are optimally combined, the number of large-diameter column devices is unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipeline, the column diameter is enlarged, and the number is reduced by half. The column devices are arranged as follows:

[0160] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number 1# Demethanizer 1 1# Demethanizer 1 2# Demethanizer 1 1# Deethanizer 1 1# Deethanizer 1 2# Deethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 2# Depropanizer 1 1# Depropanizer 1 1# Depropanizer 1 Debutanizer 1 Propylene rectifier 1 Propylene rectifier 1

[0161] The total number of column devices is 14, and thus the number of column devices is reduced from 18 of the prior art to 14 of the present application, with a reduction rate of 22.22%. After the small-diameter column devices are combined into one and the column diameter is enlarged, the motor power of the corresponding material conveying pump is doubled, the matched voltage level is increased to 10,000V according to the design specification, the cable loss of the power transmission can be reduced by 0.12%, and the energy consumption is also reduced accordingly. Finally, 99.95mol% of polyethylene product and 99.6mol% of polypropylene product are obtained.

[0162] Comparative Example 15

[0163] In the existing technology production scale of 3.6 million tons / year of ethylene cracking device separation unit, the A production line and the B production line use oil absorption separation process, and the column devices are arranged as follows:

[0164] A line B line Tower equipment name Equipment number Tower equipment name Equipment number Depropanizer 1 Depropanizer 1 Carbon monoxide absorber 1 Carbon monoxide absorber 1 Carbon monoxide desorber 1 Carbon monoxide desorber 1 Deethanizer 1 Deethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 Propylene rectifier 1 Propylene rectifier 1 Debutanizer 1 Debutanizer 1

[0165] The total number of column devices is 14, and there are problems of large number of devices and high engineering cost. The voltage level of the motor device matched with the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0166] Example 17

[0167] The production scale is 3.6 million tons / year of two process production lines of A line and B line, and the oil absorption separation process is used. The column devices are optimally combined, the number of large-diameter column devices is unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipeline, the column diameter is enlarged, and the number is reduced by half. The column devices are arranged as follows:

[0168] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number Depropanizer 1 Depropanizer 1 Deethanizer 1 Carbon monoxide absorber 1 Carbon monoxide absorber 1 Debutanizer 1 Carbon monoxide desorber 1 Carbon monoxide desorber 1 Ethylene rectifier 1 Ethylene rectifier 1 Propylene rectifier 1 Propylene rectifier 1

[0169] The total number of column devices is 12, thereby the number of column devices is reduced from 14 in the prior art to 12 in the present application, the reduction rate is 14.29%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 10000V according to the design specification, the cable loss of conveying electric energy can be reduced by 0.13%, the energy consumption is also reduced accordingly, and finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0170] Comparative Example 16

[0171] In the prior art separation unit of an ethylene cracking device with a production scale of 3 million tons / year, the A production line adopts a sequential separation process, the B production line adopts a front deethanization separation process, and the column devices are set as follows:

[0172]

[0173]

[0174] The total number of column devices is 15, there are problems of too many devices and high engineering cost, and the voltage level of the motor device supporting the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of conveying electric energy is large.

[0175] Example 18

[0176] Two production lines with a production scale of 3 million tons / year, the A production line adopts a sequential separation process, the B production line adopts a front deethanization separation process, the column devices are optimized and combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one, the column diameter is enlarged, and the number is reduced by half, and the column devices are set as follows:

[0177] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number Demethanizer 1 Deethanizer 1 Debutanizer 1 Deethanizer 1 Carbon dioxide absorber 1 Carbon dioxide green oil absorber 1 Demethanizer 1 Ethylene rectifier 1 Ethylene rectifier 1 Depropanizer 1 Depropanizer 1 Methane stripper 1 Propylene rectifier 1 Propylene rectifier 1

[0178] The total number of column devices is 14, thereby the number of column devices is reduced from 15 in the prior art to 14 in the present application, the reduction rate is 6.67%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 6000V according to the design specification, the cable loss of conveying electric energy can be reduced by 0.09%, the energy consumption is also reduced accordingly, and finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0179] Comparative Example 17

[0180] In the prior art separation unit of an ethylene cracking device with a production scale of 300 million tons / year, the A production line adopts a sequential separation process, the B production line adopts a front depropanization separation process, and the tower device is set as follows:

[0181]

[0182]

[0183] The total number of tower devices is 16, there are problems of large number of devices and high engineering cost, the voltage level of the motor device corresponding to the material conveying pump matched with the small-diameter tower device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0184] Example 19

[0185] The production scale is 300 million tons / year of two production lines, the A production line adopts a sequential separation process, the B production line adopts a front depropanization separation process, the tower device is optimized and combined, the number of large-diameter tower devices is unchanged, a cross-line pipeline is arranged between the A line and the B line, the two small-diameter tower devices are combined into one, the tower diameter is enlarged, and the number is reduced by half, and the tower device is set as follows:

[0186] A line B line A line and B line combined Tower equipment name Number Tower equipment name Number Tower equipment name Number Demethanizer 1 High pressure depropanizer 1 Debutanizer 1 Deethanizer 1 Low pressure depropanizer 1 Carbon dioxide green oil absorber 1 Pre-demethanizer 1 Ethylene rectifier 1 Demethanizer 1 Depropanizer 1 Deethanizer 1 Methane stripper 1 Ethylene rectifier 1 Propylene rectifier 1 Propylene rectifier 1

[0187] The total number of tower devices is 15, the number of tower devices is reduced from 16 in the prior art to 15 in the present application, the reduction rate is 6.25%, after the two small-diameter tower devices are combined into one and the tower diameter is enlarged, the motor power of the corresponding material conveying pump is doubled, the matched voltage level is increased to 6000V according to the design specification, the cable loss of the power transmission can be reduced by 0.09%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

[0188] Comparative Example 18

[0189] In the prior art separation unit of an ethylene cracking device with a production scale of 300 million tons / year, the A production line adopts a front depropanization separation process, the B production line adopts a front depropanization separation process, and the tower device is set as follows:

[0190] A line B line Tower equipment name Equipment number Tower equipment name Equipment number Deethanizer 1 High pressure depropanizer 1 Carbon dioxide absorber 1 Low pressure depropanizer 1 Demethanizer 1 Predemethanizer 1 Ethylene rectification column 1 Demethanizer 1 Depropanizer 1 Deethanizer 1 Propylene rectification column 1 Ethylene rectification column 1 Debutanizer 1 Propylene rectification column 1 Debutanizer 1

[0191] The total number of tower devices is 15, there are problems of large number of devices and high engineering cost, the voltage level of the motor device corresponding to the material conveying pump matched with the small-diameter tower device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0192] Example 20

[0193] The production scale is 3 million tons / year of two production lines, the A production line adopts a front de-ethanization separation process, the B production line adopts a front de-propanization separation process, the column devices are optimally combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, small-diameter column devices are combined into two, the column diameter is enlarged, and the number is reduced by half, and the column devices are arranged as follows:

[0194] A line B line A line and B line combined Tower equipment name Quantity Tower equipment name Quantity Tower equipment name Quantity Deethanizer 1 High pressure depropanizer 1 Debutanizer 1 Carbon dioxide absorber 1 Low pressure depropanizer 1 Demethanizer 1 Predemethanizer 1 Ethylene rectification column 1 Demethanizer 1 Depropanizer 1 Deethanizer 1 Propylene rectification column 1 Ethylene rectification column 1 Propylene rectification column 1

[0195] The total number of column devices is 14, so that the number of column devices is reduced from 15 in the prior art to 14 in the application, the reduction rate is 6.67%, after the small-diameter column devices are combined into two and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the matching voltage level is increased to 6000V according to the design specification, the cable loss of power transmission can be reduced by 0.09%, and the energy consumption is also reduced accordingly, finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0196] Comparative example 19

[0197] In the prior art production scale of 3.2 million tons / year of ethylene cracking device separation unit, the A production line adopts a sequential separation process, the B production line adopts a gradual separation process, and the column devices are arranged as follows:

[0198] A line B line Tower equipment name Equipment quantity Tower equipment name Equipment quantity Demethanizer 1 1# Demethanizer 1 Deethanizer 1 2# Demethanizer 1 Carbon dioxide green oil absorber 1 1# Deethanizer 1 Ethylene rectification column 1 2# Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Methane stripping column 1 1# Depropanizer 1 Propylene rectification column 1 2# Depropanizer 1 Debutanizer 1 Propylene rectification column 1 Debutanizer 1

[0199] The total number of column devices is 17, there are problems of too many devices and high engineering cost, and the voltage level of the motor device matched with the small-diameter column device corresponding to the material conveying pump is 380V according to the design specification, and the cable loss of power transmission is large.

[0200] Example 21

[0201] The production scale is 3.2 million tons / year of two production lines, the A production line adopts a sequential separation process, the B production line adopts a gradual separation process, the column devices are optimally combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, small-diameter column devices are combined into two, the column diameter is enlarged, and the number is reduced by half, and the column devices are arranged as follows:

[0202] A line B line A line and B line combined Tower equipment name Quantity Tower equipment name Quantity Tower equipment name Quantity Demethanizer 1 1# Demethanizer 1 Debutanizer 1 Deethanizer 1 2# Demethanizer 1 Carbon dioxide green oil absorber 1 1# Deethanizer 1 Ethylene rectification column 1 2# Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Methane stripping column 1 1# Depropanizer 1 Propylene rectification column 1 2# Depropanizer 1 Propylene rectification column 1

[0203] The total number of column devices is 16, thereby the number of column devices is reduced from 17 in the prior art to 16 in the present application, the reduction rate is 5.88%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 10000V according to the design specification, the cable loss of power transmission can be reduced by 0.12%, the energy consumption is also reduced accordingly, and finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0204] Comparative Example 20

[0205] In the prior art separation unit of an ethylene cracking device with a production scale of 3.2 million tons / year, an A production line adopts a sequential separation process, and a B production line adopts an oil absorption separation process, and the column devices are set as follows:

[0206] A line B line Tower equipment name Equipment quantity Tower equipment name Equipment quantity Demethanizer 1 Depropanizer 1 Deethanizer 1 Carbon one absorber 1 Carbon dioxide green oil absorber 1 Carbon one desorber 1 Ethylene rectification column 1 Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Methane stripping column 1 Propylene rectification column 1 Propylene rectification column 1 Debutanizer 1 Debutanizer 1

[0207] The total number of column devices is 15, there are problems of too many devices and high engineering cost, and the voltage level of the motor device supporting the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of power transmission is large.

[0208] Example 22

[0209] Two production lines with a production scale of 3.2 million tons / year, an A production line adopts a sequential separation process, and a B production line adopts an oil absorption separation process, the column devices are optimized and combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one, the column diameter is enlarged, and the number is reduced by half, and the column devices are set as follows:

[0210] A line B line A line and B line combined Tower equipment name Quantity Tower equipment name Quantity Tower equipment name Quantity Deethanizer 1 Depropanizer 1 Debutanizer 1 Deethanizer 1 Carbon one absorber 1 Carbon dioxide green oil absorber 1 Carbon one desorber 1 Ethylene rectification column 1 Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Methane stripping column 1 Propylene rectification column 1 Propylene rectification column 1

[0211] The total number of column devices is 14, thereby the number of column devices is reduced from 15 in the prior art to 14 in the present application, the reduction rate is 6.67%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 10000V according to the design specification, the cable loss of power transmission can be reduced by 0.12%, the energy consumption is also reduced accordingly, and finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0212] Comparative Example 21

[0213] In the prior art separation unit of an ethylene cracking device with a production scale of 3.2 million tons / year, an A production line adopts a front deethanization separation process, and a B production line adopts a gradual separation process, and the column devices are set as follows:

[0214] A line B line Tower equipment name Equipment quantity Tower equipment name Equipment quantity Deethanizer 1 1# Demethanizer 1 Carbon dioxide absorber 1 2# Demethanizer 1 Demethanizer 1 1# Deethanizer 1 Ethylene rectification column 1 2# Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Propylene rectification column 1 1# Depropanizer 1 Debutanizer 1 2# Depropanizer 1 Propylene rectification column 1 Debutanizer 1

[0215] The total number of column devices is 16, and there are problems of large number of devices and high engineering cost. The voltage level of the motor device matched with the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of power transmission is large.

[0216] Example 23

[0217] The production scale is 3.2 million tons / year of two production lines, the A production line adopts a front de-ethanizing separation process, the B production line adopts a gradual separation process, the column devices are optimally combined, the number of large-diameter column devices is unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipeline, the column diameter is enlarged, and the number is reduced by half, and the column devices are arranged as follows:

[0218]

[0219]

[0220] The total number of column devices is 15, so the number of column devices is reduced from 16 in the prior art to 15 in the present application, the reduction rate is 6.25%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the motor power of the corresponding material conveying pump is doubled, the matched voltage level is increased to 10000V according to the design specification, the cable loss of power transmission can be reduced by 0.12%, and the energy consumption is also reduced accordingly, finally 99.95mol% of polymeric grade ethylene product and 99.6mol% of polymeric grade propylene product are obtained.

[0221] Comparative Example 22

[0222] In the prior art production scale of 3.2 million tons / year of ethylene cracking device separation unit, the A production line adopts a front de-ethanizing separation process, the B production line adopts an oil absorption separation process, and the column devices are arranged as follows:

[0223] A line B line Tower equipment name Equipment quantity Tower equipment name Equipment quantity Deethanizer 1 Depropanizer 1 Carbon dioxide absorber 1 Carbon one absorber 1 Demethanizer 1 Carbon one desorber 1 Ethylene rectification column 1 Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Propylene rectification column 1 Propylene rectification column 1 Debutanizer 1 Debutanizer 1

[0224] The total number of column devices is 14, and there are problems of large number of devices and high engineering cost. The voltage level of the motor device matched with the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of power transmission is large.

[0225] Example 24

[0226] The production scale is 3.2 million tons / year of two production lines, the A production line adopts a front de-ethanizing separation process, the B production line adopts an oil absorption separation process, the tower equipment is optimally combined, the number of large-diameter tower equipment is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter tower equipment is combined into two, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0227] A line B line A line and B line combined Tower equipment name Quantity Tower equipment name Quantity Tower equipment name Quantity Deethanizer 1 Depropanizer 1 Debutanizer 1 Deethanizer 1 Carbon one absorber 1 Carbon dioxide green oil absorber 1 Carbon one desorber 1 Ethylene rectification column 1 Deethanizer 1 Depropanizer 1 Ethylene rectification column 1 Methane stripping column 1 Propylene rectification column 1

[0228] The total number of tower equipment is 13, so that the number of tower equipment is reduced from 14 in the prior art to 13 in the present application, the reduction rate is 7.14%, after the small-diameter tower equipment is combined into two and the tower diameter is enlarged, the corresponding material conveying pump motor power is doubled, the matching voltage grade is increased to 10,000 V according to the design specification, the cable loss of power transmission can be reduced by 0.12%, and the energy consumption is also reduced accordingly, finally 99.95 mol% of polyethylene product and 99.6 mol% of polypropylene product are obtained.

[0229] Comparative example 23

[0230] In the prior art production scale of 3.6 million tons / year of ethylene cracking device separation unit, the A production line adopts a front de-propane separation process, the B production line adopts a gradual separation process, and the tower equipment is arranged as follows:

[0231] Propylene rectification column A line B line Tower equipment name Equipment quantity Tower equipment name Equipment quantity 1 High pressure depropanizer 1 1# Demethanizer 1 Low pressure depropanizer 1 2# Demethanizer 1 Predemethanizer 1 1# Deethanizer 1 Demethanizer 1 2# Deethanizer 1 Deethanizer 1 Ethylene rectification column 1 Ethylene rectification column 1 1# Depropanizer 1 Propylene rectification column 1 2# Depropanizer 1 Debutanizer 1 Propylene rectification column 1

[0232] The total number of tower equipment is 17, there are problems of too many equipment and high engineering cost, the voltage grade of the motor equipment matched with the small-diameter tower equipment corresponding to the material conveying pump is 380 V according to the design specification, and the cable loss of power transmission is large.

[0233] Example 25

[0234] The production scale is 3.6 million tons / year of two production lines, the A production line adopts a front de-propane separation process, the B production line adopts a gradual separation process, the tower equipment is optimally combined, the number of large-diameter tower equipment is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter tower equipment is combined into two, the tower diameter is enlarged, and the number is reduced by half, and the tower equipment is arranged as follows:

[0235] Debutanizer A line B line A line and B line combined TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY High pressure depropanizer 1 1# de-methanizer 1 Debutanizer 1 Low pressure depropanizer 1 2# de-methanizer 1 Pre-de-methanizer 1 1# de-ethanizer 1 De-methanizer 1 2# de-ethanizer 1 De-ethanizer 1 Ethylene rectification tower 1 Ethylene rectification tower 1 1# depropanizer 1 Propylene rectification tower 1 2# depropanizer 1 Propylene rectification tower 1

[0236] The total number of column devices is 16, thereby the number of column devices is reduced from 17 in the prior art to 16 in the present application, the reduction rate is 5.88%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 10000V according to the design specification, the cable loss of the power transmission can be reduced by 0.13%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

[0237] Comparative Example 24

[0238] In the prior art separation unit of an ethylene cracking device with a production scale of 3.6 million tons / year, the A production line adopts a front depropanization separation process, the B production line adopts an oil absorption separation process, and the column devices are set as follows:

[0239] A line B line TOWER EQUIPMENT NAME EQUIPMENT QUANTITY TOWER EQUIPMENT NAME EQUIPMENT QUANTITY High pressure depropanizer 1 Depropanizer 1 Low pressure depropanizer 1 Carbon one absorption tower 1 Pre-de-methanizer 1 Carbon one desorption tower 1 De-methanizer 1 De-ethanizer 1 De-ethanizer 1 Ethylene rectification tower 1 Ethylene rectification tower 1 Propylene rectification tower 1 Propylene rectification tower 1 Debutanizer 1 Debutanizer 1

[0240] The total number of column devices is 15, there are problems of too many devices and high engineering cost, and the voltage level of the motor device supporting the material conveying pump corresponding to the small-diameter column device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0241] Example 26

[0242] Two production lines with a production scale of 3.6 million tons / year, the A production line adopts a front depropanization separation process, the B production line adopts an oil absorption separation process, the column devices are optimized and combined, the number of large-diameter column devices is kept unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one, the column diameter is enlarged, and the number is reduced by half, and the column devices are set as follows:

[0243] A line B line A line and B line combined TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY High pressure depropanizer 1 Depropanizer 1 Debutanizer 1 Low pressure depropanizer 1 Carbon one absorption tower 1 Pre-de-methanizer 1 Carbon one desorption tower 1 De-methanizer 1 De-ethanizer 1 De-ethanizer 1 Ethylene rectification tower 1 Ethylene rectification tower 1 Propylene rectification tower 1 Propylene rectification tower 1

[0244] The total number of column devices is 14, thereby the number of column devices is reduced from 15 in the prior art to 14 in the present application, the reduction rate is 6.67%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the corresponding material conveying pump motor power is doubled, the supporting voltage level is increased to 10000V according to the design specification, the cable loss of the power transmission can be reduced by 0.13%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

[0245] Comparative Example 25

[0246] In the prior art separation unit of an ethylene cracking device with a production scale of 3.6 million tons / year, the A production line adopts a gradual separation process, the B production line adopts an oil absorption separation process, and the column devices are set as follows:

[0247] A line B line TOWER EQUIPMENT NAME EQUIPMENT QUANTITY TOWER EQUIPMENT NAME EQUIPMENT QUANTITY 1# de-methanizer 1 Depropanizer 1 2# de-methanizer 1 Carbon one absorption tower 1 1# de-ethanizer 1 Carbon one desorption tower 1 2# de-ethanizer 1 De-ethanizer 1 Ethylene rectification tower 1 Ethylene rectification tower 1 1# depropanizer 1 Propylene rectification tower 1 2# depropanizer 1 Debutanizer 1 Propylene rectification tower 1 Debutanizer 1

[0248] The total number of column devices is 16, and there are problems of large number of devices and high engineering cost. The voltage level of the motor device corresponding to the material conveying pump matched with the small-diameter column device is 380V according to the design specification, and the cable loss of the power transmission is large.

[0249] Example 27

[0250] The production scale is 3.6 million tons / year of two production lines, the A production line adopts the gradual separation process, the B production line adopts the oil absorption separation process, the column devices are optimally combined, the number of large-diameter column devices is unchanged, a cross-line pipeline is arranged between the A line and the B line, the small-diameter column devices are combined into one through the cross-line pipeline, the column diameter is enlarged, the number is reduced by half, and the column devices are arranged as follows:

[0251] A line B line A line and B line combined TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY TOWER EQUIPMENT NAME QUANTITY 1# de-methanizer 1 Depropanizer 1 Debutanizer 1 2# de-methanizer 1 Carbon one absorption tower 1 1# de-ethanizer 1 Carbon one desorption tower 1 2# de-ethanizer 1 De-ethanizer 1 Ethylene rectification tower 1 Ethylene rectification tower 1 1# depropanizer 1 Propylene rectification tower 1 2# depropanizer 1 Propylene rectification tower 1

[0252] The total number of column devices is 15, so the number of column devices is reduced from 16 of the prior art to 15 of the present application, the reduction rate is 6.25%, after the small-diameter column devices are combined into one and the column diameter is enlarged, the motor power of the corresponding material conveying pump is doubled, the matched voltage level is increased to 10000V according to the design specification, the cable loss of the power transmission can be reduced by 0.13%, the energy consumption is also reduced accordingly, and finally 99.95mol% of the polymerization grade ethylene product and 99.6mol% of the polymerization grade propylene product are obtained.

Claims

1. An ethylene cracker process system comprising a cracking unit, a quench- compression unit, and a separation unit, wherein, The quenching-compression unit is provided with a cracking diesel stripping tower (C1), a cracking fuel oil stripping tower (C2), a quenching oil viscosity reduction tower (C3), a process water stripping tower (C4), a cracking gasoline stripping tower (C5) and a condensate stripping tower (C6), characterized in that the quenching-compression unit is provided with at least two quenching-compression process sub-lines, at least one device in the cracking diesel stripping tower (C1), the cracking fuel oil stripping tower (C2), the quenching oil viscosity reduction tower (C3), the process water stripping tower (C4), the cracking gasoline stripping tower (C5) and the condensate stripping tower (C6) is cross-line connected with the quenching-compression process sub-line; the separation unit is provided with at least two separation process sub-lines, and the debutanizer (C51) is cross-line connected with the separation process sub-line. The separation process sub-line is at least one of a sequential separation process sub-line, a front deethanization separation process sub-line, a front depropanization separation process sub-line, a gradual separation process sub-line and an oil absorption separation process sub-line.

2. The ethylene cracking process system of claim 1, wherein, The feed pipe line of at least one device in the cracking diesel stripping tower (C1), the cracking fuel oil stripping tower (C2), the quenching oil viscosity reduction tower (C3), the process water stripping tower (C4), the cracking gasoline stripping tower (C5) and the condensate stripping tower (C6) is connected with the cross-line pipe line.

3. The ethylene cracking process system of claim 1, wherein, The feed pipe line of the debutanizer (C51) is connected with the cross-line pipe line.

4. The ethylene cracking process system of claim 1, wherein, The separation process sub-lines are all sequential separation process sub-lines, and at least one device in a deethanizer (C11), a carbon two green oil absorption tower (C21), a depropanizer (C31), a methane stripping tower (C41) and a debutanizer (C51) is cross-line arranged between the sequential separation process sub-lines.

5. The ethylene cracking process system of claim 1, wherein, The separation process sub-lines are all front deethanization process sub-lines, and at least one device in a carbon two green oil absorption tower (C21), a demethanizer, a depropanizer (C31) and a debutanizer (C51) is cross-line arranged between the front deethanization process sub-lines.

6. The ethylene cracking process system of claim 1, wherein, The separation process sub-lines are all front depropanization process sub-lines, and at least one device in a pre-demethanizer, a demethanizer, a deethanizer (C11) and a debutanizer (C51) is cross-line arranged between the front depropanization process sub-lines.

7. The ethylene cracking process system of claim 1, wherein, The separation process sub-lines are all gradual separation process sub-lines, and at least one device in a pre-demethanizer, a demethanizer, a deethanizer (C11) and a debutanizer (C51) is cross-line arranged between the gradual separation process sub-lines.

8. The ethylene cracking process system of claim 1, wherein, The separation process sub-lines are all oil absorption separation process sub-lines, and at least one device in a deethanizer (C11) and a debutanizer (C51) is cross-line arranged between the oil absorption separation process sub-lines.

9. The ethylene cracking process system of claim 1, wherein, When the separation process sub-lines are different separation process sub-lines, a debutanizer (C51) is cross-line arranged between the separation process sub-lines.

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