IR studies of carbons—VI. The effects of KHCO3 on cellulose pyrolysis and char oxidation

✍ Scribed by C. Morterra; M.J.D. Low

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 672 KB
• Volume: 23
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(85)90026-0

✦ Synopsis

The pyrolysis in vacuum of cellulose containing 5 wt. % of KHCOs (KHC) was followed by IR photothe~al beam deflection spectroscopy, and compared with observations made with pure cetlulose (PC) [Carbon 21, 283( I983)]. The KHCO,, and KOH and K2C03 formed from it, drastically altefed the cellulose carbonization and the subsequent oxidation of the KHC chars. KHC became charred at 140 "C and the cellulose disrupted at 220 "C. The surface layer was a mixture of weak acid K salts. K$O, was not formed until 310 "C and persisted until about 500 "C, when metallic K was evolved. Unlike PC, the surface layer contained no aromatic CH structures. The carbonization of KHC proceeded more rapidly and to a greater extent than with PC. The oxidation of KHC chars was also markedly affected; bum-off occurred at much lower temperatures, and the gasification temperature range was narrower, than with PC chars.