Intensified regeneration performance of spent caustic from LPG sweetening by HiGee reactor

Abstract

Spent caustic from the desulfurization of liquefied petroleum gas has been proved to be effectively regenerated in a rotating packed bed (RPB) with classic wire mesh packing. However, the influence of the packing’s surface wettability on regeneration performance in the RPB was not clear with this oil-water two-phase system. In this work, the surface-modified packing was proposed to be used in the RPB to estimate the regeneration performance, including oxidation and separation efficiency. Three different surface-modified packings of hydrophilic surface-modified wire mesh packing (ISP), non-surface-modified wire mesh packing (NSP), and hydrophobic surface-modified wire mesh packing (OSP) were prepared and employed in the RPB for regeneration experiments. Results show that regeneration performance is in order of ISP＞NSP＞OSP. Compared with OSP, the NaSR conversion, RSSR removal efficiency, and number of transfer units of ISP increased nearly by 34%, 13%, and 21% at 1000 r/min rotational speed and 25 mm packing thickness, respectively. For the view of different packing combination, not only in the inner layer but also in the outer layer, ISP had noticeable superior regeneration performance, which displays the bright future of advanced surface-modified packing used in the RPB for process intensification of reaction and separation.