Concentration of selected aromatic hydrocarbons by extractive evaporation with ammonia

Claim 1

A PROCESS FOR SEPARATING A MIXTURE OF (1) AROMATIC HYDROCARBONS HAVING A BOILING POINT HIGHER THAN 212*F. AND (2) NONAROMATIC HYDROCARBONS BOILING AT SUBSTANTIALLY THE SAME TEMPERATURE WHICH COMPRISES CONTACTING SAID MIXTURE OF AROMATIC AND NONAROMATIC HYDROCARBONS WITH LIQUID AMMNIA CONTAINING SUBSTANTIALLY NO DILUENT IN AN EXTRACTION ZONE AT AN EXTRACTION TEMPERATURE AND AT LEAST AUTOGENOUS PRESSURE, WITHDRAWING FROM SAID EXTRACTION ZONE AN EXTRACT COMPRISING THE AROMATIC HYDROCARBONS, AMOMNIA AND A SMALL PORTION OF THE NONAROMATIC HYDROCARBONS, SUBSTANTIALLY INCREASING THE PRESSURE OF THE EXTRACT AND INTRODUCING THE EXTRACT INTO AN EXTRACT EVAPORATION ZONE AT THE ELEVATED PRESSURE, ADDING SUFFICIENT HEAT TO THE EXTRACT EVAPORATION ZONE TO RAISE THE TEMPERATURE OF SAID EXTRACT TO A TEMPERATURE HIGHER THAN THAT OF SAID EXTRACTION ZONE AND TO CONVERT THE AMMONIA TO A GAS, WITHDRAWING GASEOUS AMMONIA, AND ALONG WITH THE AMMONIA SUBSTANTIALLY ALL OF THE NONAROMATIC HYDROCARBONS AND A PORTION OF THE AROMATIC HYDROCARBONS FROM SAID EXTRACT EVAPORATION ZONE WITH SUBSTANTIALLY NO CONDENSATION AND SUBSTANTIALLY NO REFLUX, WITHDRAWING SEPARATELY SUBSTANTIALLY PURE AROMATIC HYDROCARBONS FROM SAID EXTRACT EVAPORATION ZONE, REDUCING THE PRESSURE OF THE GASEOUS AMMONIA AND HYDROCARBONS WITHDRAWN FROM SAID EXTRACT EVAPORATION ZONE TO THE PRESSURE OF THE EXTRACTION ZONE, RETURNING THE AMMONIA AND HYDROCARBONS CONTAINED THEREIN IN LIQUID FORM TO THE EXTRACTION ZONE, WITHDRAWING FROM SAID EXTRACTION ZONE RAFFINATE COMPRISING NONAROMATIC HYDROCARBONS AND LIQUID AMMONIA, SUBSTANTIALLY INCREASING THE PRESSURE OF THE RAFFINATE AND INTRODUCING THE RAFFINATE INTO A RAFFINATE EVAPORATION ZONE AT THE ELEVATED PRESSURE, ADDING SUFFICIENT HEAT TO THE RAFFINATE EVAPORATION ZONE TO CONVERT THE AMMONIA TO A GAS, WITHDRAWING AMMONIA FROM SAID RAFFINATE EVAPORATION ZONE, COOLING THE AMMONIA WITHDRAWN FROM SAID RAFFINATE EVAPORATION ZONE TO THE TEMPERATURE OF THE EXTRACTION ZONE, REDUCING THE PRESSURE OF THE AMMONIA TO THE PRESSURE OF THE EXTRACTION ZONE, RETURNING THE AMMONIA IN LIQUID FORM TO THE EXTRACTION ZONE, AND SEPARATELY WITHDRAWING NONAROMATIC HYDROCARBONS FROM SAID RAFFINATE EVAPORATION ZONE.