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Cracking furnace tube for inhibiting catalytic coking of hydrocarbon cracking furnace tube, and manufacturing method thereof

A hydrocarbon cracking furnace tube and a cracking furnace tube technology are applied to the cracking furnace tube and its manufacturing field for inhibiting coking during the cracking of petroleum hydrocarbons, and can solve the problems of weak binding force, affecting the performance of an oxide film protective layer, and being difficult to obtain. Achieve the effect of satisfying long-term use, inhibiting catalytic coking, and increasing binding force

Active Publication Date: 2015-04-15
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the lack of an intermediate transition layer between the chromium-manganese spinel protective layer and the substrate, the expansion coefficients of the chromium-manganese spinel protective layer and the substrate are inconsistent, which will generate thermal stress, so the combination with the substrate will not be too strong; and the oxygen in the patent The partial pressure is very low, which leads to a very slow rate of formation of the oxide film protective layer at the low temperature stage, and a long preparation time; at the same time, the cost of pure hydrogen used is very high, and it is not easy to obtain in olefin factories, which is not convenient for online implementation of industrial equipment
[0010] China University of Petroleum (Beijing) also discloses two patents on high-temperature treatment of cracking furnace tubes under the mixed gas of pure hydrogen and water vapor to obtain a metal oxide protective layer on the inner surface. In CN 101565807A, because it does not use gradient heating The method and the water vapor content in the gas are relatively high, which leads to a very fast growth rate of the oxide film protective layer, and the generated oxide film protective layer is not dense enough and the binding force is not strong; in CN101565808A, although the water vapor content is reduced by using ammonia, but NH 3 It will react with the metal at high temperature, which also affects the performance of the oxide film protective layer

Method used

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  • Cracking furnace tube for inhibiting catalytic coking of hydrocarbon cracking furnace tube, and manufacturing method thereof
  • Cracking furnace tube for inhibiting catalytic coking of hydrocarbon cracking furnace tube, and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] The inner surface of the 2520 nickel-chromium alloy furnace tube with a size of φ14×2×800 is bright and free of scale after machining, and the surface composition of the furnace tube is analyzed by X-ray energy dispersive spectrometer (Energy Dispersive Spectrometer, referred to as EDS). The results are shown in Table 1.

[0045] Use this furnace tube to carry out low oxygen partial pressure atmosphere treatment on a self-made laboratory device with a feed rate of 200g / h. Use H 2 、CH 4 and H 2 A gas mixture of O is used as a low oxygen partial pressure atmosphere treatment gas, where H 2 The volume percentage of O is adjusted between 0.6% and 1.2%, CH 4 8% by volume, the rest is H 2 , the flow rate of the mixed gas is 300mL / min. Specific steps are as follows:

[0046] (1) Let the furnace tube be at H 2 、CH 4 and H 2 In the atmosphere of O;

[0047] (2) Raise the temperature of the furnace tube to 600°C at a heating rate of 60°C / h, the heating process H 2 The...

Embodiment 2

[0070] The 2520 nickel-chromium alloy furnace tube in embodiment 1 is replaced with 2535 nickel-chromium alloy furnace tube, and the low oxygen partial pressure atmosphere treatment is carried out on the laboratory device in embodiment 1. Using pure H 2 As a low oxygen partial pressure atmosphere treatment gas, the whole treatment process, H 2 The volume percentage of O was kept at 1.2%, and the gas flow rate was 300ml / min. Specific steps are as follows:

[0071] (1) Let the furnace tube be at H 2 and H 2 In the atmosphere of O;

[0072] (2) Raise the furnace tube temperature to 650°C at a heating rate of 60°C / h;

[0073] (3) The furnace tube is kept at 650°C for 6 hours;

[0074] (4) Raise the furnace tube temperature to 850°C at a heating rate of 30°C / h;

[0075] (5) The furnace tube is kept at a constant temperature of 850°C for 20 hours;

[0076] After cooling, the surface composition was analyzed with a scanning electron microscope and an energy dispersive spectro...

Embodiment 3

[0084]The 2520 nickel-chromium alloy furnace tube in Example 1 was replaced with a 3545 nickel-chromium alloy furnace tube, and the low oxygen partial pressure atmosphere treatment was carried out on the laboratory device in Example 1. Use H 2 、C 2 h 6 and H 2 A gas mixture of O is used as a low oxygen partial pressure atmosphere treatment gas, where H 2 The volume percentage of O is 0.6%~1.2%, C 2 h 6 2% by volume, the rest is H 2 , the flow rate of the mixed gas is 300ml / min. Specific steps are as follows:

[0085] (1) Let the furnace tube be at H 2 、C 2 h 6 and H 2 In the atmosphere of O;

[0086] (2) Raise the temperature of the furnace tube to 750°C at a heating rate of 60°C / h, the heating process H 2 The volume percentage of O is 1.2%;

[0087] (3) The furnace tube is kept at 750°C for 6 hours, and the constant temperature process is H 2 The volume percentage of O is 1.2%;

[0088] (4) Raise the temperature of the furnace tube to 950°C at a heating rate o...

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Abstract

The invention relates to a cracking furnace tube for inhibiting catalytic coking of a hydrocarbon cracking furnace tube, and a manufacturing method thereof. The furnace tube comprises a substrate and an oxide film combined with the substrate, wherein the oxide film is an oxide film obtained by compounding three layers of oxides, the inner layer oxide near the substrate contains at least one selected from SiO2, CeO2 and Y2O3, the middle layer oxide comprises at least one selected from Cr2O3, FeO, Fe2O3 and NiO, the surface layer oxide comprises at least one selected from MnO and MnxCr3-xO4, and x is 0.5-1.5. The cracking furnace tube is manufactured by the following steps: carrying out a step-by-step heating treatment on a nickel-chrome alloy furnace tube material in low oxygen partial pressure gas, and generating an oxide film obtained by compounding three layers of oxides on the inner surface. According to the present invention, Fe content and Ni content in the oxide film of the cracking furnace tube are low, such that catalytic coking of the radiation-section furnace tube of the cracking furnace can be significantly inhibited when the cracking furnace tube is used for production of low carbon number olefin by the hydrocarbon cracking furnace tube.

Description

technical field [0001] The invention relates to a cracking furnace tube, more specifically, to a cracking furnace tube for suppressing coking during cracking of petroleum hydrocarbons and a manufacturing method thereof. 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 that has plagued ethylene production for a long time. Coking will increase the thermal resistance of the furnace tube and reduce the heat transfer coefficient, resulting in an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C10G9/20C10G9/16C23C8/14
Inventor 王申祥王国清王红霞郏景省
Owner CHINA PETROLEUM & CHEM CORP
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