Superfund Innovative Technology Evaluation (SITE)
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|Texaco Gasification Process
Texaco's Gasification Process (TGP) is an entrained-bed, noncatalytic, partial oxidation process in which carbonaceous substances react at elevated temperatures and pressures, producing a gas containing mainly carbon monoxide and hydrogen. This product, called synthesis gas, can be used to produce other chemicals or be burned as fuel. The TGP processes waste feedstocks at pressures above 20 atmospheres and temperatures between 2,000 and 2,800 F. Waste feedstocks may include organic and inorganic contaminated soils, sludges and sediments; chemical wastes; and petroleum residues. Slurried wastes are pumped to a specially designed injector mounted at the top of a refractory-lined gasifier. The waste feed, oxygen, and an auxiliary fuel, such as coal, react and flow downward through the gasifier to a quench chamber that collects the slag. A scrubber further cools and cleans the synthesis gas. The technology was demonstrated at the Texaco Montebello Research Laboratory, South El Monte, California, in January 1994 using a mixture of clean soil, coal, and soil from the Purity Oil Sales Superfund site, located in Fresno, California. The mixture was slurried and spiked with lead, barium, and chlorobenzene. Forty tons of slurry was gasified during the three demonstration runs. Analysis of the dry synthesis gas revealed an average composition of 37% hydrogen, 36% carbon monoxide, 21% carbon dioxide, with organic contaminants registering < 0.1 ppm, except for methane (55 ppm). The DRE (destruction and removal efficiency) for the VOC spike was >99.99% and the heavy metal spikes in the ash slag met the toxicity characteristic leaching procedure (TCLP) criteria.