Treatment Of Recycle Solvents For Zinc Chloride Catalyzed Coal Liquefaction

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (873 download)

DOWNLOAD NOW!

Download or read book Catalytic Liquefaction by Zinc Chloride Melts at Pre-pyrolysis Temperature written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid-phase catalysts have proved effective for opening chemical linkages in subbituminous coal and capping the reactive segments with hydrogen atoms or other low-molecular-weight groups. The preferred temperature range is 275 to 325°C (530 to 620°F), so that the linkages are opened by controlled catalytic action rather than by thermal pyrolysis which requires appreciably higher temperatures. The best catalyst melt compositions used to date are zinc chloride with 10% water together with tetralin, and zinc chloride with 15% methanol and 3% of zinc metal. Useful residence times range from 30 minutes, or less, to as high as 90 minutes. The products of the treatment have predominately low (300) to medium (3000) molecular weights, analogous to syncrudes and solvent-refined coal. Conversions to pyridine-soluble products of 95% or better are achieved with Wyodak Roland Seam coal, and to date as much as 70% of that coal has been recovered as toluene-solubles (oils and asphaltenes). A major benefit of these conversion conditions is the almost complete absence of by-product char or gas. At these lower temperatures the hydrogen pressures used can be less than in conventional liquefaction; for example, 40 atm rather than 100 atm or more. Hydrogen consumption is significantly lower than in conventional liquefaction; the product yield is higher; and simpler procedures are foreseen for product recovery. The research performed so far clearly shows the industrial potential of homogeneous (liquid-phase) catalysts in penetrating and interacting with the mild temperature and pressure of these studies.