Field synergy effect-based cracking furnace tube

Abstract

The invention relates to a field synergy effect-based cracking furnace tube. The cracking furnace tube is characterized in that: the tube wall of the furnace tube is uniformly provided with a plurality of cambered flow guide grooves which protrude inwards and are helical along the axial direction; the furnace tube sequentially consists of a guide section and a stabilization section in the flowingdirection of a material; the helix angle of the guide section increases gradually and changes within the range from 0 to 60 degrees; the length of the guide section is 5 to 50 times the internal diameter of the furnace tube; when a certain angle is reached, the material enters the stabilization section; and the helix angle of the flow guide groove at the stabilization section is constant and the same as the helix angle at the tail end of the guide section. The height for the part of the flow guide groove which protrudes inwards does not exceed 1 / 6 of the internal diameter of the tube. The material produces a radial secondary flow in the tube through the helical flow guide grooves distributed on the tube wall; and under the action of the secondary flow, a concentration gradient and a density gradient which are favorable for a cracking reaction are formed so as to fulfill the aim of reducing the temperature of the tube wall, improving the yield of the ethylene and reducing the coking.

Description

technical field [0001] The invention relates to a furnace tube used in the radiant section of an ethylene cracking furnace or other tubular cracking furnaces, in particular to a furnace tube that can improve the flow state of materials in the tube, enhance heat transfer and mass transfer effects, and can promote cracking reactions and improve the target Product yield, reducing coking produced by cracking furnace tubes. Background technique [0002] Tubular cracking is currently the main method of ethylene production. Ethylene produced by tubular cracking furnaces accounts for more than 99% of the world's total ethylene production. It is generally believed that for ethylene cracking reaction, higher temperature, shorter residence time, and lower hydrocarbon partial pressure are beneficial to the formation of target products (ethylene, propylene) and inhibit the occurrence of side reactions. Since the heat required for the cracking of the raw material is transferred to the c...

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Problems solved by technology

[0005] Although the method of increasing the heat transfer area in the tube reduces the radial temperature difference in the tube, but because the heat transfer surface is also the coking location, the narrowing of the flow cross section makes it more sensitive to coking, so the coke cleaning period is shortened, which is not conducive to Operation of cracking furnace

[0006] By adding turbulence in the tube, the degree of turbulence of the material in the tube and the scouring of the tube wall are improved, and the radial temperature difference in the tube is reduced to a certain extent, which is beneficial to weaken the formation of coking, but the turbulence in the tube occupies The effective volume in the tube, and the flow resistance in the tube is significantly increased

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