Suppressing and slowing method of coking in ethylene cracking furnace tube

An ethylene cracking furnace and furnace tube technology, applied in cracking, non-catalytic thermal cracking, petroleum industry, etc., can solve problems such as prolonged continuous production time, reduce carburizing tendency, improve service life, and do not increase the effect of operating procedures

Inactive Publication Date: 2004-11-17
CHINA PETROCHEMICAL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The patent US6537388 mainly deposits a layer of chromium-containing coating on the surface of the alloy substrate through chemical vapor deposition, physical vapor deposition, thermal sputtering, etc., and then deposits a layer of alu

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Treatment of HK alloy furnace tube: The first step is to make a piece of HK alloy furnace tube into a test piece, clean its surface before the test, analyze its surface composition with a scanning electron microscope, put the test piece into an atmosphere treatment container, and pass through the container. Enter the mixed gas generated after the decomposition of liquid ammonia, and carry out atmosphere treatment on the furnace tube. The treatment process is: from room temperature, the temperature is raised by 5°C per minute, and when it reaches 800°C, it is kept for 0.5 hours, and then the temperature is raised by 3°C per minute to 1150°C. Keep the temperature at ℃ for about 30 hours, and analyze its surface composition with a scanning electron microscope after the test is over.

[0017] In the second step, the alloy powder composed of 20% aluminum, 15% chromium, 7% silicon, 3% rare earth ferrosilicon alloy, 1.5% ammonium chloride and the rest being Al2O3 and the pre-pr...

Embodiment 2

[0020] Treatment of HP alloy: the first step is to make a piece of HP alloy furnace tube used on site into a test piece, clean its surface before the test, analyze its surface composition with a scanning electron microscope, put the test piece into an atmosphere treatment container, and put it in the container The mixed gas produced by the decomposition of liquid ammonia is introduced to treat the furnace tube atmosphere. The treatment process is: from room temperature, the temperature is raised by 7°C per minute, and when it reaches 800°C, it is kept for 2 hours, and then the temperature is raised by 4°C to 1000°C per minute. Keep the temperature at 1000°C for about 50 hours, and analyze its surface composition with a scanning electron microscope after the test is over.

[0021] In the second step, the alloy powder composed of 7% of aluminum, 10% of chromium, 5% of silicon, 3% of rare earth ferrosilicon, 1% of ammonium chloride, 0.5% of sodium fluoride and the rest is clay pow...

Embodiment 3

[0024] Coking tests were carried out in the laboratory to evaluate the performance of the alloy layer in inhibiting and mitigating coking. The HK furnace tube specimen treated in Example 1 was installed in an experimental cracking furnace for testing. The amount of coke deposited on the inner wall of the furnace tube is measured by weighing method, and the performance of the alloy layer to inhibit and slow down coking is determined according to the amount of coking.

[0025] Using naphtha as raw material, the coking test results are shown in Table 3. The results show that the coking of the furnace tube after treatment is reduced by about 90%, and the effect of inhibiting and slowing down the coking is very obvious. The test conditions are as follows:

[0026] The furnace tube size is: 12×2×400.

[0027] Cracking raw material: naphtha

[0028] Vaporizer temperature: 650°C

[0029] Cracking furnace temperature: 900°C

[0030] Oil / water: 1:0.5

[0031] Specimen ...

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Abstract

The invention discloses a method for suppressing and slowing coking in ethylene cracking furnace tube comprising the steps of, (1) atmosphere processing, using the gaseous mixture produced from liquid ammonia decomposition as reducing gas to process the boiler tube atmosphere, (2) alloying treatment, preparing the alloy powder and adhesive into pulp, coating onto the surface of the processed furnace tube, drying and solidifying at 50-120 deg. C, placing into heating-furnace for diffusion treatment, cooling the furnace tube after the completion of the treatment, and removing the alloy powder coating on the furnace tube surface.

Description

technical field [0001] The invention relates to a method for anti-coking treatment on the surface of the furnace tube of an ethylene cracking furnace, which can suppress and slow down the generation and deposition of coke on the inner wall of the furnace tube during the hydrocarbon cracking process. More specifically, the present invention relates to a method for forming an alloy layer on the surface of a furnace tube through combined treatment of atmosphere and alloying, which reduces catalytic coking, thereby reducing the generation and deposition of coke on the inner wall of the furnace tube, and reducing the carburization tendency of the furnace tube. Extend the decoking period and service life of the furnace tube. Background technique [0002] Ethylene is the basic raw material for synthetic chemical fibers, plastics, and rubber. 95% of the world's ethylene comes from the cracking of hydrocarbons. The raw materials of hydrocarbon cracking to ethylene are divided into g...

Claims

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Application Information

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IPC IPC(8): C10G9/16
Inventor 崔新安郑战利申明周李朝法宁朝辉李春贤张宏飞
Owner CHINA PETROCHEMICAL CORP
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