The measurement of phase equilibria for process streams at operating temperatures and the implications for the CRE liquefaction project
- CRE, Clwyd (United Kingdom)
CRE operates the Liquid Solvent Extraction process at its pilot plant in North Wales, UK. The process involves feeding pulverised coal, slurried with a solvent, to a digester in which much of the coal is dissolved. Filtration removes residual solids. The coal solution is fed to an ebulliating bed hydrocracker, together with hydrogen at 200 bar at 425{degrees}C. The catalytic reaction adds hydrogen to the coal solution which is distilled to recover solvent and yield a product. The vessels and pipework are externally heated to ensure that liquids can be pumped but temperatures arc not high enough to initiate regressive reactions with consequent formation of carbonaceous solids. However, coal derived liquids are complex mixtures of hydrocarbons which are not soluble in all proportions at all temperatures. Precipitation may occur, leading to blockages in process lines and equipment with subsequent interruption to plant operation. Coal liquids can be regarded simply as a three component system comprising pitch (material with a boiling point >450{degrees}C), saturated hydrocarbon (saturates) having a boiling point <450{degrees}C and distillate solvent, the remainder of the material boiling below 450{degrees}C. Coal solution, of which LSE recycle solvent is a particular case, is a mixture of these three components. A study was undertaken to examine the quantity and nature of precipitates formed from coal solutions of various compositions, with a view to preventing plant shutdowns caused by blocked lines.
- OSTI ID:
- 254863
- Report Number(s):
- CONF-940813-; TRN: 96:003482-0225
- Resource Relation:
- Conference: 208. American Chemical Society (ACS) national meeting, Washington, DC (United States), 21-26 Aug 1994; Other Information: PBD: 1994; Related Information: Is Part Of 207th ACS national meeting. Volume 39, Nos. 1, 2, 3 and 4; PB: 1304 p.
- Country of Publication:
- United States
- Language:
- English
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