Pyrolysis and gasification of lignocellulosic solid wastes for activated-carbon production

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1981

OSTI ID:6211749

Mackay, D M

The production process under consideration was pyrolysis of raw solid-waste material (precursor) to form a carbonaceous char followed by activation, or expansion of the pore system of the char by gasification with carbon dioxide at 900/sup 0/C. Char yield was found to be determined by precursor composition (percent lignin, holocellulose, etc.) and pyrolysis heating rate. Both factors were found to exert their main influence on char yield during pyrolysis below 500/sup 0/C. Selected chars prepared by pyrolysis at the lower heating rates (1 and 15/sup 0/C/min) to 500/sup 0/, 700/sup 0/, and 900/sup 0/C were gasified for various lengths of time in a CO/sub 2/ atmosphere at 900/sup 0/C. Pore-volume analysis of the final products was performed by nitrogen adsorption 77K and mercury porosimetry. The rate of mass loss and development of the pore system during gasification was found to vary with prior pyrolysis conditions: e.g., low heating rate or longer exposure to high temperature during pyrolysis led to lower rate of gasification. However, the pore volume developed for a given mass loss due to gasification reactions was independent of prior pyrolysis conditions. The latter result was apparently due to the similarity of the pore systems present in the chars immediately prior to the onset of the gasification reactions, i.e. after the char had heated to the gasification temperature. Because the heating rate during pyrolysis below 500/sup 0/C was the critical factor controlling char yield at 900/sup 0/C, the final yield of activated carbon (i.e. gasified char) of a specified pore volume was also influenced mainly by the pyrolysis heating rate below 500/sup 0/C.

• OSTI ID: 6211749
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ACTIVATED CARBON
PRODUCTION
CELLULOSE
GASIFICATION
PYROLYSIS
SOLID WASTES
CHARS
FEASIBILITY STUDIES
HEATING RATE
LIGNIN
TEMPERATURE DEPENDENCE
ADSORBENTS
CARBOHYDRATES
CARBON
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
NONMETALS
ORGANIC COMPOUNDS
POLYSACCHARIDES
PYROLYSIS PRODUCTS
SACCHARIDES
THERMOCHEMICAL PROCESSES
WASTES
320604* - Energy Conservation
Consumption
& Utilization- Municipalities & Community Systems- Municipal Waste Management- (1980-)