Coal Liquefaction and Deashing Studies. 2. Solvent Refined Coal Process

Abstract

In a laboratory-scale study performed under Fort Lewis Solvent Refined Coal (SRC) Pilot-Plant conditions with Kentucky coal, integrated gravity settling produced an SRC with 0.1% ash content if Soltrol 130 paraffinic naphtha was added as antisolvent in 0.3:1 to 0.5:1 antisolvent/liquefaction solvent ratio. Higher ratios produced clogging deposits. SRC pilot-plant filter feed containing 10% solids was used in the tests, and 86% was recovered as deashed product. The separation was sensitive to upflow velocity, and a low velocity of 0.4 in./min was required in an 8 in. settler. A commercial plant processing 25,000 tons/day of coal would require thirty-two 40 ft dia settlers. Recycled Soltrol 130, contaminated with 6% tar acids and approx. 12% nonparaffinic materials, had a much lower efficiency than fresh solvent; the Kauri-Butanol value correlated linearly with the efficiency. Various other aspects of the process are also discussed.