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Sorbents for Desulfurization of Refinery
Off‑Gases--TDA
Research, Inc., 12345 W. 52nd Ave., Wheat Ridge, CO 80033‑1916; 303‑940‑2300; www.tda.com
Dr. Gokhan Alptekin, PhD, Principal Investigator, galptekin@tda.com
Mr. John D. Wright, Business Official, jdwright@tda.com
DOE Grant No. DE‑FG02‑07ER84802
Amount:
$750,000
The
off-gases from various refinery operations could be converted into valuable
chemicals, such as hydrogen, instead of being sent to flare, where they
contribute to energy loses and greenhouse gas emissions. However, refinery off-gases contain large
concentrations of sulfur and other impurities.
Before these gases can be converted to hydrogen, sulfur and other
impurities must be removed to prevent poisoning of the reforming catalysts used
in the conversion process.
Traditionally, desulfurization has been achieved by a two-step process
consisting of hydrodesulfurization (HDS) and
subsequent removal of H2S with an expendable chemical
absorbent. Although this approach has
long been used for the desulfurization of natural gas feed stocks (where the
sulfur level does not exceed 5-10 ppmv), its utility
for use with high sulfur off-gases is cost prohibitive. This project will develop a novel physical
adsorbent to desulfurize refinery off-gases. The sorbent, which will be operated either in
an expendable or regenerable manner, operates at near
ambient temperatures (20-60oC) and reduces the sulfur content of the
gas stream to ppb levels, thereby protecting the catalyst used in the
downstream conversion process. Unlike
conventional sorbents, the material removes not only H2S but also
organic sulfur compounds (such as mercaptans,
sulfides and thiophenes) with high capacity and
higher removal efficiency. Phase I (1)
developed low cost, regenerable sorbents that can
remove sulfur compounds from refinery off-gases with very high capacity; (2)
demonstrated that the regenerable sorbent maintains
its capacity for over 20 absorption/regeneration cycles; and (3) established
the potential for the cost-effective production of hydrogen from
sulfur-contaminated refinery off-gas streams.
Phase II will improve sorbent performance, scale-up its production using
commercial manufacturing techniques, design and fabricate a prototype test
unit, and carry out a detailed system analysis and engineering assessment.
Commercial Applications and Other Benefits as described by
the awardee: The new sorbent technology should provide