Process for decreasing coking of convection sections of cracking furnaces

A process method and cracking furnace technology, which is applied in the field of reducing coking in the convection section of the cracking furnace, can solve problems such as the inability to remove high polymers, and achieve the effects of avoiding coking and good technical effects

Active Publication Date: 2015-05-06
SINOPEC SHANGHAI ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is the problem that the high polymer entrained by the dilution steam ...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In the invention, a process water extraction tower is added after the process water in the process water stripping tower is discharged, and trace high polymers in the process water are removed by extraction. The pyrolysis gas produced by the cracking furnace enters the water washing tower after quenching and oil washing, the process water in the water washing tower tank enters the process water stripping tower, and the water in the process water stripping tower tank enters the process water extraction tower, contacts with the extraction agent, and the process water extraction tower tank Water enters the dilution steam generator to generate dilution steam, and the dilution steam enters the cracking furnace.

[0021] The production scale of the ethylene plant is 115,000 tons / year, and the process water treatment capacity entering the process water extraction tower is 28.0 tons / hour. The operating temperature of the process water extraction tower is 20°C, the operating pre...

Embodiment 2

[0023] According to the conditions and steps described in Example 1, only the production scale of the ethylene plant was changed to 1.2 million tons / year, and the process water treatment capacity entering the process water extraction tower was 292.6 tons / hour. The operating temperature of the process water extraction tower is 20°C, the operating pressure is 0.01MPaG, and the extractant is n-pentane. The high polymer contained in the process water entering the process water extraction tower is 10.0 mg / L. After extraction and separation, the high polymer contained in the process water exiting the process water extraction tower is 1.0 mg / L, and the removal rate reaches 90%. During the normal operation period of the entire ethylene plant for 1 to 3 years, no coking phenomenon occurred in the convection section of the cracking furnace.

Embodiment 3

[0025] According to the conditions and steps described in Example 2, the operating temperature of the process water extraction tower is 180° C., the operating pressure is 1.2 MPaG, and the extractant is n-nonane. The high polymer contained in the process water entering the process water extraction tower is 10.0 mg / L. After extraction and separation, the high polymer contained in the process water exiting the process water extraction tower is 1.0 mg / L, and the removal rate reaches 90%. During the normal operation period of the entire ethylene plant for 1 to 3 years, no coking phenomenon occurred in the convection section of the cracking furnace.

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PUM

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Abstract

The invention relates to a process for decreasing coking of convection sections of cracking furnaces and is mainly used for solving the problem that the high polymers carried by the diluted steam cannot be removed in the prior art. The process for decreasing coking of the convection sections of cracking furnaces comprises the following steps: cracking gas generated by a cracking furnace enters a bath tower after undergoing quenching and oil washing; the process water of the bath tower enters a process water stripping tower; the water of the process water stripping tower enters a process water extraction tower to contact an extraction agent; the water of the process water extraction tower enters a diluted steam generator to generate diluted steam; and the diluted steam enters the cracking furnace. The extraction agent is selected from at least one of n-pentane, n-hexane, n-heptane, n-octane, n-nonane, isopentane, isohexane, cyclopentane, cyclohexane, benzene, methylbenzene and xylene. According to the technical scheme, the process has the effect of preferably solving the problem and can be used for the convection sections of cracking furnaces.

Description

technical field [0001] The invention relates to a process for reducing coking in the convection section of a cracking furnace. Background technique [0002] During the thermal cracking of petroleum hydrocarbon steam to produce ethylene, the cracking raw material and dilution steam enter the cracking furnace in a certain proportion to reduce the partial pressure of hydrocarbons and increase the yield of ethylene. After the reaction, the cracked gas and dilution steam are condensed into process water in the water washing tower, and then stripped by the process water stripping tower, and sent to the dilution steam generator to generate dilution steam for recycling. Once the diluted steam entrains a small amount of high polymer, it will cause coking in the convection section of the cracking furnace, which will affect the heat transfer effect of the convection section, shorten the operation period of the cracking furnace, and even block the furnace tube in the convection section....

Claims

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Application Information

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IPC IPC(8): C10G9/16
CPCC10G9/16
Inventor 何琨陈明辉洪蕾朱冠楠
Owner SINOPEC SHANGHAI ENG
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