Techno-economic analysis (40) has shown that removing chemical contaminants such as tar, ammonia, chlorine, sulfur, alkali metals, and particulates has the single greatest effect on the cost of liquid fuel synthesis. To date, gas cleanup and conditioning technologies are unproven in integrated biorefinery applications. Although water quench is an effective approach for removing tars and other particulates from the syngas, it is highly problematic from efficiency and waste disposal perspectives. Therefore, developing catalytic consolidated tar and light hydrocarbon reforming is desirable to eliminate the need for water quench.

An appropriate target for tar and light hydrocarbon reforming is to convert all tars and light hydrocarbons to syngas to a sufficient level as to not require an additional steam methane-reforming unit operation. Specific research needed to accomplish these objectives is as follows:

Perform tar deactivation/regeneration cycle tests to determine activity profiles to maintain the required long-term tar-reforming catalyst activity

• Perform catalyst studies to determine deactivation kinetics and mechanisms by probing catalyst surfaces to uncover molecular-level details

• Determine optimized catalyst formulations and materials at the pilot scale to demonstrate catalyst performance and lifetime as a function of process conditions and feedstock

• Design catalysts with higher tolerances for sulfur and chlorine poisons to enable further process intensification

• Lower or eliminate the sulfur and chlorine removal cost prior to reforming to achieve further reductions in gas cleanup costs

• Optimize the water gas shift activity of reforming catalysts to reduce or eliminate the need for an additional downstream shift reactor.