Multicycle Investigation of Normal Paraffin Separation from Naphtha To Improve Olefin and Aromatic Feed

A programmed control double-column adsorber was built to investigate the steady operation of the normal paraffin separation from naphtha. The naphtha from Shanghai Gaoqiao Petrochemical Company (SGPC) was separated into a raffinate oil rich in non-normal hydrocarbons and a desorption oil rich in normal paraffins, using zeolite SA as an adsorbent. In this paper, we investigate the effects of the adsorption/desorption temperature, feed space velocity, desorption gas space velocity, and switch time on the steady separation of normal paraffins. The adsorbability observed from the breakthrough curves of normal paraffins is consistent with the adsorption energies. The optimal conditions for the adsorption/desorption process were an operation temperature of 270 degrees C, a naphtha feed space velocity of 90.1 h(-1), a switch time of 30 min, a desorption gas N-2, space velocity of 127.5 h(-1), and an intermediate Oil cutting time of 2 mm. With the Cutting Intermediate Oil (CIO) process, the normal paraffin content in raffinate oil was 3.42% and the potential aromatic content was 12.14% higher than that of naphtha. The normal paraffin content of desorption oil was 96.61%, and the ethylene yield was 15.08% higher than that of naphtha.