IMPROVED METHOD AND DEVICE FOR NON-DISPERSIVE CONTACTING OF LIQUID-LIQUID REACTIVE SYSTEM

摘要

Field of the invention The present invention relates to an improved method and device for non-dispersive contacting of liquid-liquid reactive system. In particular, the present invention relates to a process and an apparatus for separating impurities from a liquid by a non-dispersive contacting of liquid-liquid reactive systems, said liquids being immiscible with each other. Background of the invention There are many impurities/contaminants present in the downstream hydrocarbon products like LPG, gasoline, naphtha, kerosene, diesel etc, from petroleum crude processing units. These contaminants appear in hydrocarbon products due to natural source or produce during passing through different processing stages. The impurities like napthenic acid in diesel, hydrogen sulphide, mercaptans and COS in gasoline, LPG, naphtha and kerosene obtained from different units are required to be removed to meet the desired specifications which are becoming more and more stringent in order to meet the environmental statutory regulation. These hydrocarbons are treated with either caustic or amine solution or by both in a contactor. As will be apparent to a person skilled in the art, a contactor should ensure proper contacting of immiscible liquid- liquid system. Such contactors could be a packed column, tray column, mixing valve or static mixer depending on specific application. For example, for removing H2S/mercaptan from hydrocarbon stream, mixing valve is used. In mixing valve, one phase gets dispersed into the other phase as droplets, at the expense of shear energy. In this process ratio of hydrocarbon and caustic phase is important for maintaining efficiency of the process. Such process is effective when the reaction of the impurities with the second liquid is very fast. However, such processes suffer carryover of the dispersed phase along with the continuous phase. All these processes generates certain degree of turbulence between the phases. Contactors are also known in which minimum turbulence is generated in the contact zone. Such contactors are made of fibre bundles (US Patent No3 3,754, 377; 3,758,404