A method for reducing coking in cracking furnace tubes

A cracking furnace tube and furnace tube technology, used in cracking, non-catalytic thermal cracking, petroleum industry and other directions, can solve the problems of furnace tube metal corrosion, olefin product pollution, corrosive pollution, etc. Production cycle time, the effect of reducing coking rate

Active Publication Date: 2015-08-12
内蒙古冠泰环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the coking inhibitor may cause corrosion to the metal of the furnace tube and pollute the downstream olefin products, and judging from the application of coking inhibitors at home and abroad in industrial devices, it is more suitable for ethane and other light components with a single component. Hydrocarbon raw materials, for domestic cracking raw materials dominated by naphtha, coking inhibitors do not prolong the operation cycle of cracking furnaces much, coupled with their own shortcomings of corrosiveness and pollution, so far there is no large-scale industrial application of coking inhibitors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment １

[0025] The cracking tube is HK40 tube, the cracking raw material is naphtha, and the cracking product is ethylene.

[0026] The method for alleviating cracking furnace tube coking comprises the following steps:

[0027] (1) Before coating the coke suppression coating on the inner surface of the cracking furnace tube, pre-treat the inner surface of the cracking furnace tube at 3 atmospheres: the pre-oxidation temperature is 800°C, and the treatment is 6 hours. The pre-oxidation atmosphere is water vapor, A mixture of carbon dioxide, CH4 and hydrogen in a molar ratio of water vapor: carbon dioxide: CH 4 : Hydrogen = 2:25:35:20.

[0028] (2) Coating an anti-coking coating on the inner surface of the cracking furnace tube, preheating the cracking equipment to a temperature of 900°C under 3 atmospheres, using water vapor as the carrier gas, the flow rate of water vapor is 850g / h, adding tetramethyl Silane and hydrogen sulfide, the molar ratio of Si and S is 7:2. The concentratio...

Embodiment 2

[0032] The cracking tube is HP40 tube, the cracking raw material is naphtha, and the cracking product is ethylene.

[0033] The method for alleviating cracking furnace tube coking comprises the following steps:

[0034] (1) Before coating the coke suppression coating on the inner surface of the cracking furnace tube, pre-treat the inner surface of the cracking furnace tube at 2 atmospheres: the pre-oxidation temperature is 780°C, and the treatment is 5 hours. The pre-oxidation atmosphere is water vapor, A mixture of carbon dioxide, CH4 and hydrogen in a molar ratio of water vapor: carbon monoxide: C 2 h 6 =2:40:35.

[0035](2) Apply an anti-coking coating on the inner surface of the cracking furnace tube, preheat the cracking equipment to a temperature of 1000°C under 2 atmospheric pressure, use water vapor as the carrier gas, and the flow rate of water vapor is 900g / h, then add silane , a mixture of chlorosilane and sulfur, wherein the molar ratio of Si and S is 7:2, the c...

Embodiment 3

[0039] The cracking tube is HK40 tube, the cracking raw material is naphtha, and the cracking product is ethylene.

[0040] The method for alleviating cracking furnace tube coking comprises the following steps:

[0041] (1) Before coating the coke suppression coating on the inner surface of the cracking furnace tube, pre-treat the inner surface of the cracking furnace tube at 1 atmospheric pressure: the pre-oxidation temperature is 760°C, the treatment is 4 hours, and the pre-oxidation atmosphere is CH 4 and hydrogen, the molar ratio is CH 4 : Hydrogen = 45:14.

[0042] (2) Apply an anti-coking coating on the inner surface of the cracking furnace tube, preheat the cracking equipment to a temperature of 800°C under 1 atmospheric pressure, use water vapor as the carrier gas, and the flow rate of water vapor is 870g / h, and then add silane and hydrogen sulfide, wherein the molar ratio of Si and S is 7:4, the concentration of the mixture in water vapor is 3500ppm, and a composite...

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Abstract

The invention provides a method for alleviating coking of cracking furnace tubes. The following steps are adopted: before coating the coke suppression coating on the inner surface of the cracking furnace tube, the inner surface of the cracking furnace tube is pretreated; the inner surface of the cracking furnace tube is coated with an anti-coking coating; and the coking inhibitor is added to the cracking raw material. The present invention reduces the formation of coking by compounding anti-coking technology, greatly reduces the coking rate of high-temperature cracking of hydrocarbons, and prolongs the service life of hydrocarbon cracking equipment.

Description

technical field [0001] The invention relates to the technical field of suppressing coking of hydrocarbon cracking furnace tubes, in particular to a method for reducing coking of cracking furnace tubes. Background technique [0002] The current method of producing short-chain olefins is mainly realized by high-temperature thermal cracking of hydrocarbons. The high-temperature thermal cracking process of hydrocarbons has complicated reactions. During the decomposition process of cracking raw materials, intermediate free radicals will undergo polycondensation reaction and dehydrogenation reaction, which will make the cracked products move to the direction of coke formation. That is the so-called secondary reaction, so it is inevitable to coke on the inner wall of the cracking furnace tube and the inner wall of the quenching boiler tube. Coking will increase the thermal resistance of the furnace tube, reduce the heat transfer coefficient, increase the wall temperature, increase...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C10G9/20
Inventor 张成如
Owner 内蒙古冠泰环保科技有限公司
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