Method for preventing ethylene cracking furnace from coking

A technology of ethylene cracking furnace and cracking furnace, which is applied in the direction of hydrocarbon cracking, hydrocarbon production, organic chemistry, etc. It can solve problems such as coking, coking when the furnace is shut down, and affecting the operation cycle of the cracking furnace, so as to change the coke structure, suppress coking, and suppress non- Homogeneous catalytic coking effect

Inactive Publication Date: 2008-10-01
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

[0006] However, only setting enhanced heat transfer furnace tubes such as twisted sheet tubes in the radiant section of the ethylene cracking furnace has limitations. The operating cycle of the furnace, but there is still coking between the enhanced heat transfer components such as twisted sheets and the inner wall of the furnace tube. After a period of operation, the cracking furnace will have to be shut down due to severe coking; The liquid coking inhibitor injected into the cracking furnace also has its limitations, that is, the liquid coking inhibitor inhibits coke formation or changes the coke structure through chemical reactions. It can make the coke soft and leave the cracking furnace with the reactant flow, but still Some coke is deposited on the inner wall of the furnace tube, which affects the operating cycle of the cracking furnace

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  • Method for preventing ethylene cracking furnace from coking
  • Method for preventing ethylene cracking furnace from coking

Examples

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Effect test

Embodiment 1

[0033] Embodiment 1 and embodiment 2 are the result that industrial cracking furnace is processed.

[0034] Example 1

[0035] The device is a 60,000 tons / year ethylene SRT-IV (HC) industrial cracking furnace, which is divided into six groups of feed materials, and three waste heat boilers are connected in parallel. In the furnace tube of the cracking furnace radiant section, twisted tubes are arranged in the form of mutual intervals. , the twisted sheet twists 180°, and the distance between two adjacent twisted sheet tubes is 15 pitches; during the operation of the cracking furnace (the cracking raw material is heavy diesel oil), the heavy diesel oil feed rate is 26t / h, and the diluted The steam feed rate is 19.5t / h, and under the companionship of the carrier gas steam (9kg / h), n-butanethiol is continuously injected into the cracking furnace along with the cracking raw materials, and the injection rate is 1.5kg / h. The weight ratio of n-butanethiol to raw material is about 58...

Embodiment 2

[0037] The device is a 30,000-ton / year ethylene GK-V cracking furnace, which is divided into four groups of feed materials. There are two waste heat boilers. In the furnace tube of the radiant section of the cracking furnace, twisted sheet tubes are arranged in the form of mutual intervals, and the twisted sheets are twisted. 180°, and the distance between two adjacent twisted sheets is 20 pitches; during the hot standby period before the cracking furnace is put into oil operation, the outlet temperature of the cracking furnace is 700-850°C, and the sulfur-phosphorus compound tributyl phosphate tri Thioester (wherein the atomic molar ratio of elemental sulfur and elemental phosphorus is S: P=3: 1), accompanied by carrier gas water vapor (6kg / h), is injected into the cracking furnace from the spanning section of the cracking furnace. The amount is 2.8kg / h, and the injection time is 5 hours; then steam cracking is carried out, and the cracking raw material is naphtha, and the nap...

Embodiment 3

[0043] Simulate the SRT-III type cracking furnace, adopt the method of the present invention, add 3 sections of twisted sheet tubes in the furnace tube of the radiant section, when the cracking furnace outlet temperature is 800 ° C, the mass concentration is 0.3% ethion-naphtha The oil injection agent is injected into the cracking furnace from the spanning section of the cracking furnace for pretreatment, wherein the atomic molar ratio of sulfur and phosphorus is S:P=2:1, the injection rate is 200g / h, and the treatment time is 30 minutes; then When naphtha cracking was carried out at the outlet temperature of the cracking furnace at 840°C, the ethion-naphtha injection was continued to be injected from the spanning section of the cracking furnace until the end of the test, and the injection rate was 16g / h. The physical properties of raw naphtha are: distillation range 48-211°C, specific gravity D 15.6 0.7287g / ml, sulfur content 165PPM; cracking conditions: cracking temperature...

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Abstract

The invention relates to a method for restraining an ethylene cracking furnace from coking. The method comprises the following steps: before and / or during the cracking furnace uses oil, a liquid coke inhibitor is put into the ethylene cracking furnace, wherein, the coke inhibitor is at least one compound of a sulfur compound and a phosphorous compound, and / or at least a sulfur-phosphorous compound; the radiant section pipe in the ethylene cracking furnace comprises at least one section of enhanced heat transfer pipe such as twisted tape pipe. The method of the invention not only restrains heterogeneous phase catalytic coking and gas phase radical coking, but also generates strong scouring over pipe wall under the function of the twisted tape, thereby further washing away coke which has turned soft, reducing opportunities for coke to sedimentate on pipe wall, the twisted tape and between the inner wall of the furnace pipe and the quantity, effectively restraining the cracking furnace from coking, obviously prolonging the service life and operational cycle time of the cracking furnace and improving the economic benefits of ethylene plants.

Description

technical field [0001] The invention relates to a method for suppressing coking in an ethylene cracking furnace in the field of petrochemical industry. Background technique [0002] In the pyrolysis ethylene production plant, the cracking furnace is the most critical core equipment, and about 60% of the energy consumption of ethylene production is consumed in the cracking furnace. The cracking furnace tube is the component with the highest operating temperature in the ethylene plant. The cracking reaction of hydrocarbons is carried out in the furnace tube. Due to the secondary reactions such as polymerization and condensation, it is inevitable to generate coke scale on the inner wall of the cracking furnace tube and the inner wall of the quenching boiler tube. . Coking increases the thermal resistance of the tube wall, reduces the heat transfer coefficient, increases the wall temperature and causes local overheating; coking increases the energy consumption of the pyrolysis ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C4/02C07C11/04
Inventor 戴伟付晓阳王红霞陈硕杜志国
Owner CHINA PETROLEUM & CHEM CORP
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