CN213623997U

CN213623997U - Diluent steam generator for ethylene cracking

Info

Publication number: CN213623997U
Application number: CN202022169522.8U
Authority: CN
Inventors: 张高博; 张炳辰; 白艳芳; 魏云辉
Original assignee: SHANGHAI HUIDE ENERGY INTEGRATION TECHNOLOGY CO LTD
Current assignee: SHANGHAI HUIDE ENERGY INTEGRATION TECHNOLOGY CO LTD
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-07-06
Anticipated expiration: 2030-09-28

Abstract

The utility model relates to an ethylene cracking is with diluting steam production device, including quench oil autogenous production dilution steam conveyer pipe, medium pressure steam conveyer pipe and heat exchanger, quench oil autogenous production dilution steam conveyer pipe and the shell side entry linkage of heat exchanger, the shell side export of heat exchanger is through diluting steam duct connection to ethylene cracking furnace, medium pressure steam conveyer pipe respectively with the tube side entry of heat exchanger and dilute steam duct connection, still include low pressure steam conveyer pipe and vapor compression device, low pressure steam conveyer pipe is connected with vapor compression device's steam inlet, vapor compression device's steam outlet and quench oil autogenous production dilution steam duct connection. The utility model discloses the realization utilizes low pressure steam to replace outsourcing medium pressure steam as the supplementary steam of dilution steam, realizes other surplus low pressure steam's reuse in ethylene cracker or the factory, effectively reduces the manufacturing cost that ethylene schizolysis need consume dilution steam.

Description

Diluent steam generator for ethylene cracking

Technical Field

The utility model belongs to the technical field of dilute steam production, especially, relate to an ethylene schizolysis is with diluting steam production device.

Background

The ethylene cracking reaction is carried out by heating raw oil or raw material gas for producing ethylene to high temperature in an ethylene cracking furnace. Introducing steam into the furnace tube while introducing the reaction raw materials, wherein the steam is used as inert gas and is used for diluting the raw materials, the steam is called dilution steam, and the pressure of the steam is 0.5-0.7 MPa. The steam has two functions: (1) the hydrocarbon partial pressure in the furnace tube is reduced, and the ethylene yield is improved; (2) the water vapor and the carbon deposition in the furnace tube generate water gas reaction, so that the deposition speed of the coke in the furnace tube is reduced.

The temperature of the diluted steam entering the cracking furnace is required to be 170 ℃ and 180 ℃, and the pressure is 0.5-0.7 MPa. There are currently two sources of dilution steam. One part is produced by a quench oil system, and the other part is supplemented by purchased medium pressure steam (1.3-1.6 MPa). The supplemental medium pressure steam has two effects. One function is to superheat the autogenous dilution steam. Because the produced dilution steam is saturated steam, in order to meet the requirement of an ethylene device on the superheat degree of the dilution steam, the heat exchanger shown in figure 1 is utilized, medium-pressure steam is adopted as a heat source to superheat the dilution steam, and the temperature of the dilution steam entering the ethylene cracking furnace after heat exchange is controlled by the flow of the medium-pressure steam. Another effect of the supplemental medium pressure steam is to supplement the dilution steam that is not sufficient. As ethylene plants scale up, dilution steam usage increases, and the amount of intermediate pressure steam that needs to be replenished also increases. For a set of 100 ten thousand tons/year ethylene device, the outsourcing dilution steam which needs to be introduced from a pipe network is as much as 70t/h, and the cost of the outsourcing dilution steam is as high as 7644 ten thousand yuan/year according to the calculation of 130 yuan/t.

The low-pressure steam generally refers to 0.2-0.5MPaG steam, and mainly comes from the back pressure of a steam turbine, the flash evaporation of high-temperature condensed water and byproduct steam in the process. The surplus of low-pressure steam is generally treated by emptying or cooled into condensed water, so that a large amount of heat is lost.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a dilution steam generation device is used in ethylene schizolysis is provided, realize utilizing low pressure steam to replace outsourcing medium pressure steam as the supplementary steam of dilution steam, realize the recycle of other surplus low pressure steam in ethylene schizolysis device or the factory, effectively reduce the manufacturing cost that ethylene schizolysis need consume dilution steam.

The utility model provides a technical scheme that its technical problem adopted provides an ethylene schizolysis is with diluting steam production device, including quench oil autogenous production dilution steam delivery pipe, middling pressure steam delivery pipe and heat exchanger, quench oil autogenous production dilution steam delivery pipe and the shell side entry linkage of heat exchanger, the shell side export of heat exchanger is through diluting steam delivery pipe connection to ethylene cracking furnace, middling pressure steam delivery pipe still includes low pressure steam delivery pipe and steam compression device with the tube side entry and the dilution steam delivery pipe connection of heat exchanger respectively, low pressure steam delivery pipe is connected with steam compression device's steam inlet, steam compression device's steam outlet and quench oil autogenous production dilution steam delivery pipe connection.

And pressure control valves are respectively arranged on connecting branches of the medium-pressure steam conveying pipe, the heat exchanger and the dilution steam conveying pipe, the dilution steam conveying pipe is provided with a pressure sensor, and the pressure control valves are connected with the pressure sensor and perform valve control according to detection signals of the pressure sensor.

The vapor compression device comprises a driving machine, a speed-increasing gear box and a vapor compressor, wherein the vapor compressor drives the speed-increasing gear box through the driving machine to compress vapor.

The pipeline between the steam outlet of the steam compression device and the quench oil self-produced dilution steam delivery pipe is provided with a temperature sensor, a temperature control valve is arranged on a cooling water pipe of the steam compression device, and the temperature control valve is connected with the temperature sensor and is controlled by a detection signal of the temperature sensor.

Advantageous effects

The utility model discloses a merge into quench oil from production and dilute steam and carry out the heat transfer after carrying out compression treatment to the other surplus low pressure steam in the production of ethylene cracker or factory, obtain the dilution steam that satisfies ethylene cracking needs, can realize utilizing low pressure steam to replace the additional steam of buying the middling pressure steam outward as dilution steam, realize the reuse of other surplus low pressure steam in ethylene cracker or the factory, effectively reduce the manufacturing cost that ethylene cracking needs consumption dilution steam.

Drawings

Fig. 1 is a schematic structural diagram of the prior art.

Fig. 2 is a schematic structural diagram of an embodiment of the present invention.

Detailed Description

The present invention will be further described with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and these equivalents also fall within the scope of the appended claims.

A dilution steam generating apparatus for ethylene cracking, as shown in FIG. 2, comprises a quench oil self-produced dilution steam transfer pipe 1, an intermediate pressure steam transfer pipe 2 and a heat exchanger 3. The quenching oil self-produced dilution steam conveying pipe 1 is connected with a shell pass inlet of a heat exchanger 3, a shell pass outlet of the heat exchanger 3 is connected to an ethylene cracking furnace through a dilution steam conveying pipe 4, and a medium-pressure steam conveying pipe 2 is respectively connected with a tube pass inlet of the heat exchanger 3 and the dilution steam conveying pipe 4. And pressure control valves are respectively arranged on connecting branches of the medium-pressure steam conveying pipe 2, the heat exchanger 3 and the dilution steam conveying pipe 4, the dilution steam conveying pipe 4 is provided with a pressure sensor, and the pressure control valves are connected with the pressure sensor and perform valve control according to detection signals of the pressure sensor.

The device also comprises a low-pressure steam delivery pipe 5 and a steam compression device, wherein the low-pressure steam delivery pipe 5 is connected with a steam inlet of the steam compression device, and a steam outlet of the steam compression device is connected with the quenching oil self-produced dilution steam delivery pipe 1. The steam compression device comprises a driving machine 7, a speed-increasing gear box 8 and a steam compressor 9, wherein the steam compressor 9 drives the speed-increasing gear box 8 through the driving machine 7 to compress steam. A temperature sensor is arranged on a pipeline between a steam outlet of the steam compression device and the quench oil self-produced dilution steam delivery pipe 1, a temperature control valve is arranged on a cooling water pipe 6 of the steam compression device, and the temperature control valve is connected with the temperature sensor and is controlled by a valve according to a detection signal of the temperature sensor.

FIG. 1 shows a dilution steam treatment scheme before reforming: at present, the consumption of dilution steam of an ethylene cracking device is 70t/h, the temperature is 203 ℃, and the dilution steam has two sources: 1) the flow rate of dilution steam (0.56MPa) produced by quenching oil is 45t/h, the temperature is 163 ℃, and 1.0MPa steam is adopted as a heat source to overheat the dilution steam, and the flow rate is 1 t/h; 2) 1.0MPa steam is supplemented into the dilution steam pipe network, and the flow is 25 t/h. The diluted steam is superheated through a heat exchanger and then is converged with 1.0MPa steam to be sent to an ethylene cracking furnace, and the total flow of the 1.0MPa steam is 26 t/h. The low-pressure steam (0.35MPa) of the ethylene device is surplus for 10t/h in summer and enters a condensate system through circulating water cooling.

As shown in fig. 2, the utility model discloses flow after transformation: the flow rate of dilution steam (0.56MPa) is 70t/h, and the temperature is 163 ℃; the steam flow of 0.35MPa is 25t/h, the pressure is increased to 0.6MPa by a steam compressor 9, the temperature of the outlet of the compressor is controlled to be 180 ℃ by a temperature control valve 2, the temperature is merged into a pipeline before dilution steam superheating, then the pipeline exchanges heat with 1.0MPa steam (3t/h) by a heat exchanger, the temperature after the heat exchange is 203 ℃, and the original 1.0MPa steam serial dilution steam pipeline is continuously reserved for standby.

The improvement effect: the excessive 0.35MPa steam of the ethylene cracking device can be recycled by 10t/h, the waste heat of the aromatic hydrocarbon device is recycled to generate 0.35MPa steam by 15t/h instead of 1.0MPa steam by 25t/h, the circulating water consumption is saved by 350t/h, the air cooler saves 40kW per hour, and the device consumes 803 kW. The steam price of 1.0MPa is 120 yuan/t, the coefficient of the steam of 1.0MPa is 0.98t/t according to the conversion of the steam of 0.35MPa, therefore the price after the conversion is 117 yuan/t, the electricity price is 0.6 yuan/degree, the price of circulating water is calculated according to 0.2 yuan/t, the annual running time is calculated according to 8400 hours, 4 months in winter, 8 months in summer, the total benefit is 1842 ten thousand yuan/year, the investment is 600 ten thousand yuan, and the investment recovery period is 0.3 year.

Claims

1. The utility model provides a dilute steam generating device for ethylene cracking, includes quench oil autogenous production dilution steam conveying pipe (1), medium pressure steam conveying pipe (2) and heat exchanger (3), quench oil autogenous production dilution steam conveying pipe (1) and the shell side entry linkage of heat exchanger (3), the shell side export of heat exchanger (3) is connected to the ethylene cracking furnace through dilution steam conveying pipe (4), medium pressure steam conveying pipe (2) are connected its characterized in that with the tube side entry and the dilution steam conveying pipe (4) of heat exchanger (3) respectively: still include low pressure steam delivery pipe (5) and vapor compression device, low pressure steam delivery pipe (5) are connected with vapor compression device's steam inlet, vapor compression device's steam outlet and quench oil autogenous production dilution steam delivery pipe (1) are connected.

2. The dilution steam generation device for ethylene cracking according to claim 1, wherein: and pressure control valves are respectively arranged on connecting branches of the medium-pressure steam conveying pipe (2) and the heat exchanger (3) and the dilution steam conveying pipe (4), the dilution steam conveying pipe (4) is provided with a pressure sensor, and the pressure control valves are connected with the pressure sensor and perform valve control according to detection signals of the pressure sensor.

3. The dilution steam generation device for ethylene cracking according to claim 1, wherein: the steam compression device comprises a driving machine (7), a speed-increasing gear box (8) and a steam compressor (9), wherein the steam compressor (9) drives the speed-increasing gear box (8) to compress steam through the driving machine (7).

4. The dilution steam generation device for ethylene cracking according to claim 1, wherein: the pipeline between steam compression device's steam outlet and quench oil autogenous production dilution steam delivery pipe (1) is equipped with temperature sensor, be equipped with the temperature-sensing valve on steam compression device's cooling water pipe (6), the temperature-sensing valve is connected with temperature sensor and carries out valve control according to temperature sensor's detected signal.