METHOD OF PRODUCING VINYL AROMATIC HYDROCARBONS Russian patent published in 2025 - IPC C07C5/333 C07C15/44 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing vinyl aromatic hydrocarbons by dehydrogenation of corresponding alkyl aromatic hydrocarbons on a fixed catalyst bed in the presence of steam superheated in a superheating furnace. Method includes heating, evaporation and overheating of alkylaromatic hydrocarbon mixture, formation and cooling of reaction mass with heat utilization, its condensation, separation of condensate into hydrocarbon and water layers, with subsequent extraction of vinyl aromatic hydrocarbon from hydrocarbon layer and unreacted alkyl aromatic hydrocarbon with its return to the process. Obtained water condensate is used to cool the reaction mass by means of their direct interaction in a heat and mass exchange apparatus. Also, the proposed method includes purification of water condensate using a fractionation column in the presence of an extractant, its evaporation in a recovery boiler and return to the process at the dehydrogenation step, cleaning of uncondensed gas and blowing from pumps and reservoirs from aromatic hydrocarbons in irrigated packed scrubber, use of heat of flue gases of steam superheating furnace. At that, into the heat and mass exchanger below the inlet of the reaction mass and into the water condensate purification column below the inlet of the extractant, live steam is introduced, and heat of flue gases of steam superheating furnace is used for heating of water condensate purified in rectification column before supply to waste heat boiler. Irrigation of the packed scrubber for purification of uncondensed gas is carried out with a rectified alkylaromatic hydrocarbon or a mixture of rectified oil and a return alkylaromatic hydrocarbon.

EFFECT: improved controllability, technological stability, efficiency and environmental safety of the process.

2 cl, 1 dwg