Steam cracking method

Abstract

The invention discloses a steam cracking method. The method comprises the following steps: vaporizing unsaturated hydrocarbons in a vaporization device, mixing the vaporized gaseous unsaturated hydrocarbons with dilution steam, introducing the above obtained cracking raw material mixture to the convection section of a cracking furnace, preheating the cracking raw material mixture, introducing the preheated cracking raw material mixture from the middle position of the radiation section of the cracking furnace, and carrying out a cracking reaction, wherein a diameter ratio of a preheating row to a connecting box is 1:5-12, and preferably 1:8-10, and the middle position of the radiation section of the cracking furnace is the 1 / 4-1 / 5 position of the height of the cracking furnace. The steam cracking method improves the heating speed of the cracking raw material in a cracking furnace tube in order to improve the selectivity of the cracking reaction, so the yield of ethylene, propylene and butadiene is substantially improved.

Description

technical field [0001] The invention relates to a steam cracking method. Background technique [0002] Low-carbon olefins such as ethylene, propylene and butadiene are important basic raw materials for the petrochemical industry. At present, the method of producing low-carbon olefins is mainly based on the tube furnace petroleum hydrocarbon steam cracking process. According to statistics, about 99% of ethylene, more than 50% of propylene and more than 90% of butadiene in the world are produced through this process. [0003] There are two main sources of raw materials for the production of low-carbon olefins such as ethylene, propylene and butadiene. One is light hydrocarbons by-product of natural gas, such as ethane, propane, butane and natural gasoline, etc.; Products, such as refinery gas, naphtha, diesel, and secondary processing products, such as coking hydrogenated naphtha, hydrogenated tail oil, etc. A common feature of these raw materials is that most of them are sa...

AI Technical Summary

Problems solved by technology

[0031] The purpose of the present invention is to provide a new steam cracking method in order to overcome the problem that unsaturated hydrocarbons are injected into the cracking furnace as cracking raw materials and coking will occur in the convection section

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