Technologies for Enhancing Refinery Gas Value

The trend of processing heavy and sour crude is resulting in 'fuel long' refineries which seek to export energy in the form of refinery fuel gas or are looking for other ways to extract value from the fuel gas system. There are common solutions that either are applicable to a few selected high-hydrogen, low-olefin streams (PSA systems or SMRs), or require chemical facilities nearby (olefin recovery with cryogenic systems), or offer low value (sale to an utility or power production). Using refinery gas as a feedstock for H2 production has high potential but available pre-treatment technologies are generally based on natural gas processing and are unable to cope with the quality and characteristics inherent to refinery fuel gas. Refinery gas is typically highly variable with high olefin, C2+ and sulfur content which makes it difficult to be processed in SMRs. Praxair has developed a patented refinery gas processor based on a short contact time catalyst that can reliably process any refinery gas and convert it into SMR suitable feed. Praxair analysis indicates that the refinery gas value for hydrogen generation is higher than the value for generating power and slightly lower than the value for using it as chemical feedstock. In addition, we will revisit refinery gas cryogenic processing and focus on integration ideas with other technologies (e.g. PSA). We will discuss how different technologies are suited to different refinery gas streams and how to optimize recovery given differing energy and capital cost constraints.