Acid Gas Removal Optimization With Energy Recovery

Abstract

Acid gas removal (AGR) using a high pressure amine solvent in a contactor tower is widely used to sweeten sour gas and render it suitable for commercial distribution. Acid gas removal is also common in other applications such as ammonia production. Single-stage hydraulic turbochargers can reduce energy use in AGR processes. In the revised process, the hydraulic turbocharger essentially replaces the pressure letdown, or level control valve at the contactor exit and the high pressure pump used to bring the solvent to contactor pressure. This significantly reduces operating costs for the acid gas removal unit. This paper will present a turbocharger based system that optimizes energy use while simultaneously fulfilling the required controls functionality of the LCV. Two turbocharger application configurations that provide the pumping redundancy that is usually required in an acid gas removal unit (AGRU) are evaluated. A complete description of the turbocharger solution for acid gas removal is presented including control system response analysis to different signals from the plant. A case study of an installed turbocharger operating in an acid gas removal unit since 2010 in Northeast China is also presented. This installation had a unique bearing failure that is explored along with the resulting solution.