A bio refinery needed to remove hydrogen sulfide from syngas as part of their fuel conversion process. The plant converted agriculture and forest waste feedstocks into high purity, “drop-in” synthetic fuels using thermochemical/catalytic conversion and liquid fuel production technologies. The required H2S removal was over 99.98% to ensure a high-purity, low-sulfur final product. Peak H2S levels in the syngas were up to 100ppm and needed to be reduced to less than 20 ppb.

Monroe Environmental engineered a Wet Scrubber system that would effectively target the H2S using an amine scavenger scrubbing liquor with irrigated packing. The H2S scavenger was selected as the scrubbing chemical instead of NaOH in order to minimize operating costs over the long term. Scavengers are able to specifically target the H2S in the gas stream, whereas NaOH would also neutralize CO2 at elevated pH, significantly increasing chemical usage costs.

The scrubber was designed, fabricated, and U-stamped to ASME Section VIII & IX code.

Scope of Supply:

• Packed Tower Scrubber, 316 SS construction
• 316 SS and polypropylene packing media
• High efficiency mist eliminator
• Recirculation pump with piping and spray nozzles
• Integral liquid reservoir with level switch with make-up water feed
• pH and flow transmitters for process monitoring and operational control

The unit was designed for 1,500 SCFM @ 120°F.