Capacity increase included: A new generation of promoter for selective H2S removal

Gerald Vorberg, Torsten Katz, Georg Sieder, Justin Hearn BASF SE, Ludwigshafen/Germany,

The selective removal of H2S has become important over the last twenty years. This is driven by several factors, including 1) production of an H2S enriched, a high quality Claus gas, in widespread MDEA-based Acid Gas Enrichment (AGE) units and 2) for the monetization of sour gas fields with sweet gas resources becoming limited. Savings in energy and circulation rate and a reduction in equipment sizing are the obvious benefits of enhanced selective treatment.

The principles for AGE or selective removal of H2S with amine-based solvents follow three major routes: (a) hindered amines, controlling the selectivity primarily in the absorber; (b) various design options and absorber internals, affecting the difference in CO2 and H2S mass transfer kinetics and (c) promoted tertiary amines, focusing more on the regeneration, and thus leading to higher H2S selectivities.

Compared to conventional technologies, this advanced solution is a considerable leap forward in the selective treatment of gases. This paper considers the existing “rules of thumb” for designing selective applications and explain the effect of a new class of promoter.