Method for inhibiting coking of hydrocarbon cracking furnace tube during on-line coke burning process

A hydrocarbon cracking furnace tube and furnace tube technology, applied in cracking, non-catalytic thermal cracking, petroleum industry, etc., can solve the problems of excessive oxidation, cumbersome steps, uneven coating distribution, etc., to prolong the service life and prolong operation Cycle, the effect of reducing the amount of coking

Active Publication Date: 2012-12-05
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
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AI Technical Summary

Problems solved by technology

[0013] In view of the defects of the existing online pre-coating technology to form an anti-coking coating, such as the pre-coating steps are cumbersome, the pre-coating solution needs to be replaced repeatedly, it is not easy to operate in the industry, the pre-coating time is long, and the production time of the cracking furnace is occupied , the coating is unevenly distributed in the cracking furnace tube, and the problem of easy peeling off; and the adverse effects of online waste pot burnt on the cracking furnace radiation section furnace tube, such as excessive oxidation, local peeling and other hazards, the invention provides a new A method for pre-coating to form an anti-coking coating during the burning process to protect the cracking furnace tube

Method used

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  • Method for inhibiting coking of hydrocarbon cracking furnace tube during on-line coke burning process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Using a 2520 nickel-chromium alloy furnace tube with a size of φ14×2×800 on a self-made laboratory device with a feed rate of 200g / h, naphtha was used as a cracking raw material to conduct a pyrolysis coking evaluation test. After the pyrolysis is completed, the air is used for charring, and the CO and CO in the charred gas 2 The concentration is measured online by an infrared instrument, and the volume of the charred gas is recorded online by a wet flow meter. Finally, the amount of carbon in the charred gas is calculated as the amount of coking in the cracking process. The cracking test conditions are as follows:

[0030] Raw material: industrial naphtha (see Table 1 for physical properties)

[0031] Table 1 Physical properties of industrial naphtha

[0032]

[0033] Lysis time: 2 hours

[0034] Preheater temperature: 600°C

[0035]Cracking furnace temperature: 850°C

[0036] Water to oil ratio: 0.5

[0037] After the charring is completed, use air as the car...

Embodiment 2

[0049] The 2520 furnace tube of the same material as Example 1 and the same cracking conditions are used for testing. After the charring is completed, nitrogen is used as a carrier gas to bring hexamethyldisiloxane vapor into the furnace tube for vapor deposition. The deposition conditions as follows:

[0050] Furnace tube temperature: 700°C Air flow rate: 0.5L / min

[0051] Deposition time: 6 hours Volume percentage of hexamethyldisiloxane: 3.0%

[0052] The surface composition of the furnace tube before and after vapor deposition, the results are shown in Table 4.

[0053] Element distribution (wt%) on the surface of the furnace tube before and after vapor deposition in Table 4 Example 2

[0054] Chemical composition (wt%)

[0055] It can be seen from Table 4 that SiO is formed on the surface of the vapor deposition furnace tube 2 coating.

[0056] Continue to carry out the cracking and coking evaluation test according to the method described before untreated...

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Abstract

The present invention relates to a method for inhibiting coking of a hydrocarbon cracking furnace tube during an on-line coke burning process. The method comprises that carrier gas carrying organosilicon steam enters a radiation section of the cracking furnace tube under 1-5 atmospheric pressure at an on-line coke burning later stage of a hydrocarbon cracking furnace tube, wherein the organosilicon is subjected to vapor deposition on the inner wall of the furnace tube to form a SiO2 coating. According to the method of the present invention, cracking coking in the next cycle can be reduced with the generated SiO2 coating; the technology of the present invention has characteristics of simple process, easy implementation, and no adverse effect on the downstream system; and oxidation on the furnace tube during the coke burning process can be effectively reduced so as to prolong a service life of the furnace tube, coke burning amount during the cracking process can be reduced, and the operation cycle of the cracking furnace can be prolonged.

Description

technical field [0001] The invention relates to a method for suppressing the coking of cracking furnace tubes in the petrochemical field when hydrocarbons are cracked by steam, more specifically, it relates to a method for reducing coke in the furnace tubes of the radiation section in the later stage of combined air-steam coking Wall deposition, a method to protect cracking furnace tubes. Background technique [0002] The "trienes" (ethylene, propylene, butadiene) and "triphenyls" (benzene, toluene, xylene) produced by ethylene plants are the basic raw materials for the petrochemical industry. The output, production scale and technology of ethylene indicate the development level of a country's petrochemical industry. The current method of producing ethylene is mainly tube furnace cracking technology, which has been widely used in the world. [0003] Coking of the furnace tube in the radiant section of the cracking furnace of the tube furnace is a major technical problem th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C10G9/16
Inventor 王申祥王国清郏景省王红霞杜志国张永刚
Owner CHINA PETROLEUM & CHEM CORP
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