Heat exchange system of novel pipe plate-free methanol oxidizer

Abstract

The invention discloses a heat exchange system of a novel pipe plate-free methanol oxidizer. The heat exchange system comprises a cylinder; a reaction layer is mounted at the upper part of the cylinder; an oxygen reaction chamber is formed in the upper part of the reaction layer; the lower part of the reaction layer is a fixed reaction bed; a heat exchange spraying system is mounted at the lower part of the fixed reaction bed, and includes multiple heat exchange pipes with snake-shaped structures; fins are mounted on the heat exchange pipes; a spraying port is mounted on one side wall of the cylinder; a reaction gas outlet is formed in the lower part of one side wall of the cylinder; high-concentration formaldehyde is added in the lower part in the cylinder; and a discharge port is formed in the bottom of one side wall of the cylinder. Through the effect of the heat exchange spraying system arranged in the cylinder, the service life of equipment can be largely prolonged, and can reach 10-15 years, and the capacity is greatly improved, and can reach above 200000 t per year. Compared with equipment in prior art, the heat exchange system is higher in capacity and life for the same reaction bed area.

Description

technical field [0001] The invention relates to the technical field of heat exchange equipment, in particular to a heat exchange system of a novel tubeless methanol oxidizer. Background technique [0002] Formaldehyde gas is produced by oxidative dehydrogenation reaction at high temperature (630°C~650°C) when formaldehyde is produced by the silver process. The gas is required to pass through the high temperature zone in the shortest possible time to prevent by-products from excessive oxidation. The oxidative dehydrogenation reaction is an exothermic reaction. During the reaction process, a large amount of heat energy is generated at the same time. This part of the heat energy needs to be converted into other forms of energy through heat exchange in time to cool the reaction gas quickly, so as to ensure the product quality index. High temperature acidification leads to unqualified products. The methanol oxidizer is an important production device for the production of formal...

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Problems solved by technology

[0004] 1. The reaction product contains a large amount of hydrogen gas, which causes hydrogen embrittlement and stress corrosion of stainless steel materials and welding parts under high temperature conditions, resulting in weld cracking

[0005] 2. Due to the change of base metal material after use, the welding performance is greatly reduced, and maintenance is extremely difficult. Often, the problem of equipment leakage can only be solved by sealing the heat exchange pipe

Cause the loss of heat exchange area and affect the normal production capacity

[0006] 3. Part of the gas produced by the cooling water during evaporation will cause cavitation to the stainless steel pipes. At the same time, since the temperature of the reaction side of the tube sheet is 630°C~650°C, the temperature of the heat exchange side of the tube sheet is 150°C~155°C (the medium is water, the pressure is 0.25 MPa), the thermal expansion coefficients on both sides are very different, which causes the heat exchange tube to break and fail.

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