The relationship between specific reactivity and the pore structure of coal chars during gasification

✍ Scribed by A. de Koranyi

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 611 KB
• Volume: 27
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(89)90156-5

✦ Synopsis

Measurements of porosity and of reactivity to CO? have been made on chars by pyrolyzing three British bituminous coals of medium rank (Markham Main, Manvers Barnborough, and Manvers Wath). The porosity measurements were made by gravimetric adsorption of CO, at 195 K. Resulting isotherms were analysed by the Dubinin-Radushkevich method (D-R) to give an assessment of microporosity. The isotherms were found to have some Type II character and an attempt has been made to measure the mesopore volume by preadsorption at 77 K, according to the method of Gregg and coworkers. Reactivity measurements were made gravimetrically in CO, at 1253 K over a range of carbon burnoff (cbo) up to 80%. At selected values of cbo. the porosity of the sample was measured. The results show a remarkably linear correlation between reactivity and microporosity. It is likely that the linear correlation is not a primary one, but rather arises from the fact that active surface is related directly to total available area and that no especially active sites either develop or are consumed during burnoff.