2017 Spring Meeting and 13th Global Congress on Process Safety

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

Authors

Cristancho, D. E., The Dow Chemical Company
Sreedhar, B., Dow Chemical Company
Holden, B. S., The Dow Chemical Company (retired)
Valenzuela, M., Dow Oil & Gas
With the increase of Liquefied Petroleum Gas (LPG) demand globally, the need to remove contaminants, such as sour gases, is required in achieving specification for end-use product. Liquid-Liquid (Liq-Liq) amine treaters are critical in the removal of these gases from liquid hydrocarbon streams in refinery and gas processes.

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 ˚F (50 ˚C), 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.