Effects of methanol-NaOH treatment of coal on tar and gas formation during pyrolysis

✍ Scribed by J.P. Boudou; J. Bimer; P.D. Salbut; D. Cagniant; R. Gruber

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 807 KB
• Volume: 74
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(95)00018-z

✦ Synopsis

Vitrain from a bituminous coal was modified by selective chemical reaction to reveal particular structural characteristics of the organic matter responsible for the change in conversion during solubilization by methanol-NaOH treatment (M treatment). The selective reactions were alkylating and non-alkylating reduction according to Sternberg, performic acid oxidation, thermal decarboxylation of the oxidized vitrain, LiAlH4 reduction of the oxidized vitrain and 0-methylation of the residual hydroxyl groups. The products of M treatment were pyrolysed in a stream of helium at atmospheric pressure, and the volatile compounds were continuously detected by flame ionization or mass spectrometry. The changes in structure and reactivity during M treatment were assessed by comparing gas evolution during programmed pyrolysis of the M product with that of the initial vitrain and its modified by-products. The M treatment strongly increased the pyrolytic conversion, and correspondingly reduced the formation of molecular hydrogen during secondary pyrolysis. The methylation of aromatic systems in the coal by M treatment is a main component of this process. The oxidized vitrain and its oxidized products show the highest conversion, indicating the critical role of hydrogenation in bond-breaking and in prevention of regressive reactions during M treatment. Pre-oxidation and LiAlH, reduction enhance denitrogenation of the coal during M treatment and subsequent pyrolysis.