Self-decoking coating as well as preparation method and application thereof

A coating and self-cleaning technology, which is applied in coatings, metal material coating processes, solid-state diffusion coatings, etc., can solve the problems of lack of inhibition methods for condensation coking and free radical coking, decline in the protective effect of composite coatings, co-silicon-aluminum coatings, etc. Low permeation efficiency and other issues can be achieved to shorten the preparation time, good anti-coking effect, and inhibit inward migration

Pending Publication Date: 2022-05-27
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The surface coating of the above-mentioned cracking furnace tube can inhibit catalytic coking to a certain extent and improve the carburization resistance of the furnace tube, but there are still deficiencies in the stability of the coating itself, the bonding ability of the coating and the base material, etc. , such as at high temperature H 2 O will obviously accelerate the evaporation of chromium oxide, resulting in continuous thinning of the chromium oxide layer, which will reduce the protective effect of the composite coating, and the carburization resistance of the spinel coating itself still needs to be improved.
The silicon-aluminum coating has better anti-carburization ability, but the co-infiltration efficiency of silicon-aluminum on the surface of the furnace tube is low, requiring strict requirements for the infiltration agent
In addition, the current cracking furnace tube coating only has a good effect on catalytic coking, but still lacks effective means of inhibiting condensation coking and free radical coking

Method used

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  • Self-decoking coating as well as preparation method and application thereof
  • Self-decoking coating as well as preparation method and application thereof
  • Self-decoking coating as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Take a Cr25Ni35 substrate sample in Comparative Example 1, embed it in an inert container filled with a barrier coating penetrating agent, compact the substrate sample and the barrier coating penetrating agent material, and seal the inert container. The composition of the barrier coating penetrating agent is calculated by mass percentage: 22% of chromium powder, 0.5% of chromium fluoride, 5% of silicon powder, 1.0% of zirconium chloride, 3.0% of ammonium chloride, and 68.5% of aluminum oxide. Put the inert container into the muffle furnace for chemical heat treatment, raise the temperature in the muffle furnace from room temperature to 700°C at a rate of 10°C / min, and then from 700°C to 1030°C at a rate of 5°C / min, and keep the temperature constant 7h. After cooling, remove the penetrating agent powder, grind and polish, and control the coating thickness.

[0049] Embed the ground and polished base material in an inert container containing the penetrating agent for the...

Embodiment 2

[0052] Take a Cr25Ni35 substrate sample in Comparative Example 1, embed it in an inert container filled with a barrier coating penetrating agent, compact the substrate sample and the barrier coating penetrating agent material, and seal the inert container. The composition of the barrier coating penetration agent is calculated by mass percentage: 19% of chromium powder, 0.1% of chromium fluoride, 2% of silicon powder, 0.1% of zirconium oxide, 3.8% of ammonium chloride, and 75% of aluminum oxide. Put the inert container into the muffle furnace for chemical heat treatment, raise the temperature in the muffle furnace from room temperature to 700°C at a rate of 5°C / min, and then from 700°C to 1080°C at a rate of 1°C / min, and keep the temperature constant 9h. After cooling, remove the penetrating agent powder, grind and polish, and control the coating thickness.

[0053] Embed the ground and polished base material in an inert container containing the penetrating agent for the clear...

Embodiment 3

[0056] Take a Cr25Ni35 substrate sample in Comparative Example 1, embed it in an inert container filled with a barrier coating penetrating agent, compact the substrate sample and the barrier coating penetrating agent material, and seal the inert container. The composition of the barrier coating penetration agent is calculated by mass percentage: 20% of chromium powder, 0.3% of chromium fluoride, 3% of silicon powder, 0.5% of zirconium chloride, 1.3% of ammonium chloride, and 74.9% of aluminum oxide. Put the inert container into the muffle furnace for chemical heat treatment, raise the temperature in the muffle furnace from room temperature to 700°C at a rate of 10°C / min, and then from 700°C to 1050°C at a rate of 5°C / min, keep the temperature constant 4h. After cooling, remove the penetrating agent powder, grind and polish, and control the coating thickness.

[0057] Embed the ground and polished base material in an inert container containing the penetrating agent for the cle...

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Abstract

The invention discloses a self-decoking coating as well as a preparation method and application thereof. The self-decoking coating comprises a barrier coating and a decoking coating, wherein the barrier coating consists of Cr, Si, Al, Zr and oxides and halides thereof, and the decoking coating consists of Cr, Si, Al, self-decoking elements and oxides and halides thereof. The preparation process of the self-decoking coating comprises the following steps: firstly coating the barrier coating by a thermochemical embedding method, then coating the decoking coating, and finally carrying out stabilizing treatment to obtain the cracking furnace tube coating with strong coking inhibition performance and good coating stability. The outer layer of the self-decoking coating has rich decoking elements, and can catalyze the gasification reaction of coke and water vapor, so that the decomposition of the coating on initial condensation coking and free radical coking is realized, the carbon deposition is effectively delayed, and the service lives of the furnace tube and components can be remarkably prolonged.

Description

technical field [0001] The invention relates to the technical field of steam cracking in petrochemical industry, more specifically, to a self-cleaning coke coating and its preparation method and application. Background technique [0002] Low-carbon olefins such as ethylene, propylene, butene and butadiene are very basic chemical raw materials, especially the production capacity of ethylene, which is often regarded as a symbol of the petrochemical development level of a country and region, and is known as a modern chemical industry. Cornerstone. At present, about 98% of the world's ethylene production uses the tube furnace steam cracking process. The process has a higher ethylene yield, and co-produces propylene, butadiene, benzene, toluene, xylene, C 5 、C 9 Such basic chemical raw materials play a pivotal role in the petrochemical industry. [0003] The cracking furnace tube is the core equipment of the tube furnace steam cracking process device. Due to its long-term con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C10/58C23C12/00C10G9/00
CPCC23C10/58C23C12/00C10G9/00Y02P20/10
Inventor 张永军孙恩浩代跃利孙淑坤李振业万书宝王斯晗褚洪岭汲永钢徐显明
Owner PETROCHINA CO LTD
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