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Method for protecting manganese-chromium spinel film of cracking furnace tube against burning

A cracking furnace tube and spinel technology, applied in cracking, petroleum industry, non-catalytic thermal cracking, etc., can solve problems such as manganese-chromium spinel film shedding, reduce cracking furnace tube operating cycle, etc.

Active Publication Date: 2017-04-26
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the process of coking and burning in the cracking furnace, due to local high temperature, carbonization, and changes in the wall temperature of the cracking furnace tube, a small amount of manganese-chromium spinel film will inevitably fall off, thereby reducing the operating cycle of the cracking furnace tube
For how to reduce the shedding of the manganese-chromium spinel film during the operation of the cracking furnace, especially during the burning process, there is no literature report

Method used

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  • Method for protecting manganese-chromium spinel film of cracking furnace tube against burning

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038]In this example, the industrial cracking furnace is a CRT-Ⅳ type cracking furnace, and the raw material for cracking is naphtha, with an annual output of 60,000 tons of ethylene. A cracking furnace tube with a manganese-chromium spinel film is used, and the raw material for cracking naphtha is The operating cycle of the cracking furnace is about 200 days. After 200 days of operation, the furnace was shut down and burned. The burning process used the original cracking furnace's own burning program (see the above table 1 for details), and the initial COT was 800°C. However, due to the accumulation of a large amount of coke due to the long-term operation, after half an hour of coking, when the online analysis shows that the carbon dioxide concentration in the coke tail gas exceeds 8 volume%, the manual control is performed quickly to reduce the air volume by 10 volume% of the current air volume, and The amount of water vapor is increased by 25% by volume of the current amou...

Embodiment 2

[0040] In this example, the industrial cracking furnace is a CRT-Ⅳ type cracking furnace, and the raw material for cracking is naphtha, with an annual output of 60,000 tons of ethylene. A cracking furnace tube with a manganese-chromium spinel film is used, and the raw material for cracking naphtha is The operating cycle of the cracking furnace is about 200 days. After 200 days of operation, the furnace was shut down and burned. The burning process used the original cracking furnace's own burning program (see the above table 1 for details), and the initial COT was 800°C. However, due to the accumulation of a large amount of coke due to the long-term operation, after half an hour of coking, when the online analysis shows that the oxygen concentration in the coke cleaning tail gas is less than 12% by volume, it is quickly manually controlled to reduce the air volume by 5% by volume of the current air volume, and The amount of water vapor is increased by 50% by volume of the curre...

Embodiment 3

[0042] In this example, the industrial cracking furnace is a CRT-Ⅳ type cracking furnace, and the raw material for cracking is naphtha, with an annual output of 60,000 tons of ethylene. A cracking furnace tube with a manganese-chromium spinel film is used, and the raw material for cracking naphtha is The operating cycle of the cracking furnace is about 200 days. After 200 days of operation, the furnace was shut down and burned. The burning process used the original cracking furnace's own burning program (see the above table 1 for details), and the initial COT was 800°C. However, due to the accumulation of a large amount of coke due to long-term operation, after half an hour of coking, on-line analysis shows that when the temperature of the outer wall of the cracking furnace tube is higher than 1100 ° C, the manual control is performed quickly to reduce the air volume by 20% by volume of the current air volume, and make the water The steam volume increased by 10% by volume of t...

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Abstract

The invention relates to the field of protection of manganese-chromium spinel films of cracking furnace tubes and discloses a method for protecting a manganese-chromium spinel film of a cracking furnace tube against burning. The method comprises the steps as follows: in a burning process of the cracking furnace tube with the manganese-chromium spinel film, concentration of carbon dioxide in coke cleaning exhaust gas, concentration of oxygen in coke cleaning exhaust gas and at least one coke cleaning parameter of the temperature of the outer wall of the cracking furnace tube are monitored in real time, and the air volume and / or the steam amount is regulated when the at least one coke cleaning parameter meets any one of the following conditions of A1-A3: A1, concentration of the oxygen in the coke cleaning exhaust gas is lower than 12% by volume; A2, concentration of carbon dioxide is higher than 8% by volume; A3: the temperature of the outer wall of the cracking furnace tube is higher than 1100 DEG C. With the adoption of the method, the local hot spots of the cracking furnace tube due to rapid combustion of coke can be prevented, carbonization of manganese-chromium spinel on the inner surface of the cracking furnace tube at the high temperature is reduced, falling off of the film due to drastic fluctuation of the temperature is prevented, and accordingly, the manganese-chromium spinel film on the inner surface of the cracking furnace tube is protected.

Description

technical field [0001] The invention relates to a burning method for protecting the cracking furnace tube manganese-chromium spinel film. Background technique [0002] Ethylene is one of the most important basic raw materials in the petrochemical industry. The current method of producing ethylene is mainly tube furnace cracking technology, which has been widely used in the world. However, an unavoidable problem in the production process of ethylene is the coking and carburization of crackers during service. Coking during the cracking process will reduce the inner diameter of the furnace tube, increase the pressure drop inside the tube, and shorten the operating cycle of the cracking furnace; when the temperature of the tube wall reaches the allowable limit or the pressure drop reaches a certain level, the furnace must be shut down for coke cleaning. The coking on the inner wall of the furnace tube hinders the normal progress of the cracking reaction, affects the ethylene y...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C10G9/20C10G9/16
Inventor 郏景省王国清王红霞王申祥杜志国
Owner CHINA PETROLEUM & CHEM CORP
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