Method for suppressing coking and carbonizing for hydrocarbons steam cracking unit

A cracking device and steam technology, applied in cracking, non-catalytic thermal cracking, petroleum industry, etc., can solve the problems of shortening the service life of furnace tubes, reducing ethylene production, difficult maintenance, etc. Effect of carbon and performance deterioration, simple and easy operation method

Active Publication Date: 2011-06-15
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Disclosed in CN1236827A is a method for suppressing and slowing down the coke formation and deposition in the pyrolysis of hydrocarbons, using one or more mixtures of hydrogen sulfide, organosulfur compounds, organophosphorus compounds and organosulfur phosphorus compounds to carry out thermal cracking equipment Pretreatment, but the effect of inhibiting coking is not very ideal
Carburizing causes the furnace tube to creep and rupture, which greatly shortens the service life of the furnace tube
[0010] The existing coking suppression method has the following disadvantages: 1) it affects the downstream system and makes the operation of the latter system difficult; 2) the additive is toxic and pollutes the environment; Reduce the output of ethylene; 4) Difficulty in processing and maintenance and high cost; 5) Cannot effectively improve the carburization of cracking furnace tubes, etc.

Method used

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  • Method for suppressing coking and carbonizing for hydrocarbons steam cracking unit
  • Method for suppressing coking and carbonizing for hydrocarbons steam cracking unit

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Embodiment 1 and embodiment 2 are the result that industrial cracking furnace is processed.

[0040] Example 1

[0041] Set the solid content to 20%, SiO 2 / Al 2 o 3 =8, PH is that the aluminum silicate sol of 3~4 is diluted with water to be the SiO that oxide mass concentration is 1% 2 —Al 2 0 3 Aqueous solution of sol. The device is a 60,000 tons / year ethylene SRT-IV industrial cracking furnace, which is divided into six groups of feed materials, and three waste heat boilers are connected in parallel. During the hot standby period after the cracking furnace is burnt, the outlet temperature of the cracking furnace is 700-850°C. Under the operating pressure of 0.4Mpa, the diluted SiO 2 —Al 2 o 3 The sol aqueous solution is injected from the convection section of the cracking furnace accompanied by carrier gas water vapor (20kg / h), the injection amount is 2.0kg / h, and the injection time is 3 hours. Si0 2 —Al 2 o 3 The sol forms a layer of ceramic film on t...

Embodiment 2

[0043] Set the solid content to 20%, SiO 2 / Al 2 o 3 =8, PH is that the aluminum silicate sol of 3~4 is diluted with water to be the SiO that oxide mass concentration is 2% 2 —Al 2 o 3 Aqueous solution of sol. The device is a 30,000-ton ethylene / year GK-V cracking furnace, which is divided into four groups of feed materials and has two waste heat boilers. During the hot standby period after the cracking furnace is burnt, the outlet temperature of the cracking furnace is 700-850 °C. Under the operating pressure of 0.3Mpa, the diluted SiO 2 —Al 2 o 3 The sol aqueous solution is injected from the spanning section of the cracking furnace accompanied by carrier gas water vapor (10kg / h), the injection amount is 1.5kg / h, and the injection time is 2 hours. SiO 2 —Al 2 o 3 The sol forms a layer of ceramic film on the inner wall of the cracking furnace tube, which can inhibit the coking and carburizing of the furnace tube. Steam cracking is carried out after the cracking fur...

Embodiment 3

[0051] Simulate the SRT-III type cracking furnace, adopt the method of the present invention, when the outlet temperature of the cracking furnace is 800°C, SiO 2 Neutral silica sol with a mass concentration of 20% and a pH of 6.5 to 7.5 is diluted with water to SiO with a mass concentration of 0.5% pure oxide 2 Aqueous sol solution is injected from the spanning section of the cracking furnace, the injection amount is 200g / h, and the injection time is 1 hour, SiO 2 The sol forms a layer of ceramic film on the inner wall of the cracking furnace tube, which can inhibit the coking and carburizing of the furnace tube. After using the above method to treat the cracking furnace tube, steam cracking is carried out with naphtha as raw material. The cracking conditions are: cracking temperature 840°C, residence time 0.37 seconds, feed oil amount 800g / h, water amount 400g / h, water oil Ratio 0.5, reaction time 6 hours. The amount of coking in the simulated cracking furnace is 3.48g, whi...

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Abstract

The invention provides a method for restraining coking and carburizing of hydrocarbon steam cracking device, including the following steps: during hot standby of a cracking furnace, combination which prevents coking and carburizing is injected into the cracking furnace, wherein, the combination is sol combination containing at least one sort of silica sol, aluminum sol and zirconium sol. The method which is simple and feasible, environmental friendly and low in cost does not influence the downstream system of an ethylene plant; meanwhile, the method can effectively restrain coking and carburizing of cracking furnace tube so as to prolonging service life and operation cycle of the cracking furnace.

Description

technical field [0001] The invention relates to a method for pretreating a hydrocarbon steam cracking device. Background technique [0002] During the steam cracking of hydrocarbons to produce olefins such as ethylene and propylene, coke will inevitably be formed in the process parts of the cracking furnace tube and its quenching boiler, and the coke will be deposited on the inner wall of the cracking furnace tube and the inner wall of the quenching boiler heat exchange tube , not only hinder the heat transfer of the cracking furnace tube and the stream in the quenching boiler, increase the pressure drop of the furnace tube, but also block the pipeline, affect the normal operation of the cracking furnace, and cause a decrease in the output of main products and an increase in energy consumption. Coke will enter the alloy layer of the furnace tube wall in the form of solid solution, and react with chromium in the alloy to form chromium carbide deposits, resulting in carburizat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C10G9/16
Inventor 王红霞陈硕傅晓阳杜志国吴庆凤南秀琴
Owner CHINA PETROLEUM & CHEM CORP
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