Heat transfer tube for cracking furnace and preparation method and application thereof

Abstract

The invention relates to the field of heat conduction furnace tubes of ethylene cracking furnaces, and discloses a heat transfer tube for a cracking furnace and a preparation method and an application thereof. The heat transfer tube for the cracking furnace comprises a furnace tube main body and a reinforced heat transfer component arranged in the furnace tube main body, at least part of the inner surface of the heat transfer tube for the cracking furnace is provided with a cobalt-based coating, and the element composition of the cobalt-based coating comprises Co, Mo, Cr, Ni, C and optional rare earth elements; a base body of the heat transfer tube for the cracking furnace comprises 12-50% of chromium, 20-50% of nickel, 0.2-3% of manganese, 0-3% of silicon, 0-0.75% of carbon, 0-5% of trace elements and trace elements and the balance iron. The trace element is one or more of niobium, molybdenum, titanium, tungsten, aluminum, zirconium and rare earth, and the trace element is sulfur and / or phosphorus. According to the heat transfer pipe for the cracking furnace, the service life of the heat transfer pipe for the cracking furnace can be remarkably prolonged, and the cracking furnace can stably operate for a long time.

Description

technical field [0001] The invention relates to the field of heat conduction furnace tubes for ethylene cracking furnaces, in particular to a heat transfer tube for cracking furnaces and a preparation method and application thereof. Background technique [0002] The main function of the cracking furnace is to heat various raw material oil products, so that large molecules can be changed into small molecules at high temperature, and various basic organic raw materials such as ethylene, propylene and butadiene can be produced. The cracking furnace tube is an important part of the cracking furnace and the main place for the cracking of petroleum raw materials. The cracking furnace tube is an important medium in the heat transfer process of the cracking furnace, and the heat outside the tube will be transferred to the inside of the tube through the cracking furnace tube. The slight modification of the furnace tube of the cracking furnace will have an important impact on the ope...

AI Technical Summary

Problems solved by technology

As the residence time decreases, the diameter of the cracking furnace tube gradually decreases, especially when it is applied to a one-way tube, the coking rate of the cracking furnace tube begins to increase gradually, the diameter of the furnace tube begins to gradually decrease, and the probability of furnace tube blockage will gradually increase. The structure of the fin-enhanced heat transfer tube itself leads to a decrease in the flow surface in this area, resulting in abnormal flow velocity in the tube, and the fluid's scouring effect on the tube wall is strengthened. The hardness of the metal has decreased, and the impact of the fluid on the tube wall will lead to thinning, cracking and perforation of the tube wall in severe cases, which will affect the safe production of the entire cracking furnace

[0004] At the same time, with the development of large-scale cracking furnaces, too large cracking furnace equipment will lead to a decrease in investment economy, and at the same time bring great difficulties to the engineering of the cracking furnace. In order to reduce the size of the cracking furnace equipment, under the existing process conditions, appropriate Increase the pressure inside the furnace tube of the cracking furnace, and the pressure of the cracking furnace tube increases, the cracking reaction moves to the polycondensation reaction, and the coking on the inner wall of the furnace tube increases, which will lead to an increase in the coking rate in the tube, and then cause blockage in the area of ​​the twisted sheet enhanced heat transfer tube, As a result, the fluid in this area is abnormal. The temperature of the twisted sheet enhanced heat transfer tube is higher, the metal hardness of the material decreases, and the fluid erosion resistance of the twisted sheet enhanced tube is weakened, resulting in thinning, cracking and perforation of the furnace tube wall. The cracking of the pipe will affect the safe production of the whole cracking furnace

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