Biomass gasification in supercritical water

Citation
Mj. Antal et al., Biomass gasification in supercritical water, IND ENG RES, 39(11), 2000, pp. 4040-4053
Citations number
65
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemical Engineering
Journal title
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
ISSN journal
0888-5885 → ACNP
Volume
39
Issue
11
Year of publication
2000
Pages
4040 - 4053
Database
ISI
SICI code
0888-5885(200011)39:11<4040:BGISW>2.0.ZU;2-P
Abstract
Biomass feedstocks, including corn- and potato-starch gels, wood sawdust su spended in a cornstarch gel, and potato wastes, were delivered to three dif ferent tubular flow reactors by means of a "cement" pump. When rapidly heat ed to temperatures above 650 degreesC at pressures above the critical press ure of water (22 MPa), the organic content of these feedstocks vaporized. A packed bed of carbon within the reactor catalyzed the gasification of thes e organic vapors in the water; consequently, the water effluent of the reac tor was clean. The gas was composed of hydrogen, carbon dioxide, methane, c arbon monoxide, and traces of ethane. Its composition was strongly influenc ed by the peak temperature of the reactor and the condition of the reactor' s wall. Extraordinary yields (>2 L/g) of gas with a high content of hydroge n (57 mol %) were realized at the highest temperatures employed in this wor k. Irrespective of the reactor geometry and method of heating, all three re actors plugged after 1-2 h of use with feedstocks that contained 15 wt % or ganic material. Lower loadings of organics lengthened the time before plugg ing occurred. The plug resulted from accumulations of ash and small amounts of char formed by coking reactions involving the biomass vapors. A method for removing plugs from the reactor was developed and employed during an 8- h gasification run involving potato wastes. Extensive corrosion of each rea ctor's inner wall occurred during these tests. Nickel and other metals were leached from the reactor and deposited in the carbon catalyst. Nickel allo y tubes are not suitable for use in this application.