Cooling device and method for preparation of HDI by gas phase process

Abstract

The invention provides a cooling device for preparation of HDI by a gas phase process. The cooling device includes a spray condensation area disposed between a reactor and a reaction collector, a first nozzle is disposed at the upper part of the spray condensation area, the first nozzle is connected to a chlorobenzene conveying pipe, chlorobenzene is sprayed in the spray condensation area throughthe first nozzle to cool and absorb HDI prepared by the reactor, so that HDI can be separated from other gaseous substances, the reaction collector is equipped with a gas outlet pipe and a drain pipe,and the drain pipe sends chlorobenzene containing HDI to a next procedure. Compared with the traditional technology, the device and method provided by the invention can save energy, achieve more thorough absorption of HDI by chlorobenzene, and reduce by-product generation, thus increasing the product yield, are beneficial to normal running of the reaction, also play a cooling role, prolong the normal production time, and reach the purpose of synergy.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a cooling device and method for preparing HDI by a vapor phase method. Background technique [0002] Isocyanate (HDI) is prepared by gas phase method. How to quickly cool and separate HDI in the reactant from other substances such as phosgene and hydrogen chloride in the production process is another key point in the HDI production process. If HDI cannot be quickly cooled and separated, HDI will It will self-polymerize for a long time, and it will react with hydrogen chloride gas in the mixed gas to form salt substances at low temperature. When indirect cooling, the large temperature difference will easily block the system. The traditional indirect cooling method is also prone to wall formation (large temperature difference, high material viscosity), and the final cooling effect is not good; due to the active chemical properties of the product and high viscosity, when the tempera...

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Problems solved by technology

[0002] Isocyanate (HDI) is prepared by gas phase method. How to quickly cool and separate HDI in the reactant from other substances such as phosgene and hydrogen chloride in the production process is another key point in the HDI production process. If HDI cannot be quickly cooled and separated, HDI will It will self-polymerize for a long time, and when the temperature is low, it will react with hydrogen chloride gas in the mixed gas to form salt substances. When indirect cooling, the large temperature difference will easily block the system

The traditional indirect cooling method is also prone to wall formation (large temperature difference, high material viscosity), and the final cooling effect is not good; due to the active chemical properties of the product and high viscosity, when the temperature is low, HDI will form salts with hydrogen chloride to block the exhaust gas system

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