STYRENE PRODUCTION PROCESS Russian patent published in 2008 - IPC C07C15/46 C07C5/333 

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to production of vinylaromatic compounds and can be used in production of styrene by dehydrogenation of ethylbenzene. Process is accomplished in multistep adiabatic reactors at elevated temperatures in presence of steam to form finally contact gas. Recovery of contact gas heat is accomplished in waste-heat boilers by water condensate freed of aromatic hydrocarbons by rectification in vacuum rectifier using benzene-toluene fraction as recycled extractant while returning condensate to feed waste-heat boilers. When performing subsequent cooling of contact gas in foam apparatus with water condensate, the latter is stripped of light hydrocarbons prior to be directed to treatment. Steam formed in waste-heat boilers is sent to steam-overheating furnace and then mixed with ethylbenzene blend. Hydrocarbon condensate in vacuum rectifiers is fractioned to isolate heavy hydrocarbons, which are used in preparation of varnish KORS and as fuel for steam-overheating furnace. Removal of aromatic hydrocarbons from non-condensed gas is accomplished in packed scrubber refluxed at 5-6°C with return ethylbenzene under overpressure. Emission gas is directed to steam-overheating furnace to be combusted and resulting flue gases are used to heat water, which is then bottom of styrene rectifying column.

EFFECT: minimized waste and emission of injurious substances in heat recovery step.