(157c) Performance Evaluation of Liquid Treating Solvents in the Removal of H2s and COS from LPG

The tightened margins and reduced expenditures in refining and gas markets are calling for reduced costs which is an opportunity for optimization in all processes including LPG systems. Better tools and capabilities to optimize LPG amine treaters are needed to increase capacity, improve on-line reliability and reduce operational costs.

This paper will discuss a new experimental capability to evaluate the performance of liquid treating amine solvents used in LPG acid gas scrubbing in an effort to identify improved operating conditions and optimize solvent performance. Its operational range includes temperatures up to 120 ËšF (50 ËšC), pressures up to 300 psig (2170 kPa) and H₂S and COS loadings commonly found in the operation of liquid treaters in refineries. The flexible range of operation for the new experimental capability allows mimicking operational conditions for refinery liquid treaters.

Commodity and formulated solvents were compared using a synthetic feed stream of LPG with H₂S and COS at similar operational conditions (LPG/Solvent ratio, residence time, etc). The experimental results indicate the formulated solvents have overall improved performance, when compare to commodity solvents reaching an excellent level of H₂S and COS removal. The new experimental capability in conjunction with process simulation create a strong tool for process design and optimization of liquid extraction units for refineries in a technical area where liquid-liquid equilibrium information and process design fundamentals are limited.