NETWORK CHANGES DURING COAL PYROLYSIS: EXPERIMENT AND THEORY
| Autor: | Peter R. Solomon, Sylvie Charpenay, E. Kroo, Z-Z Yu, M.A. Serio, Mark S. Solum, Ronald J. Pugmire |
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| Rok vydání: | 1991 |
| Předmět: |
Depolymerization
Chemistry business.industry technology industry and agriculture Tar macromolecular substances complex mixtures respiratory tract diseases Solvent Chemical engineering Vaporization otorhinolaryngologic diseases medicine Organic chemistry Coal Char Swelling medicine.symptom business Macromolecule |
| DOI: | 10.1016/b978-0-7506-0387-4.50123-6 |
| Popis: | Publisher Summary This chapter discusses the network changes during coal pyrolysis. Coal pyrolysis is a complicated combination of chemical and physical processes in which coal is transformed at elevated temperatures to produce gases, tar, and char. These processes are described in the functional group—depolymerization, vaporization, and crosslinking (FG–DVC) model of coal pyrolysis. An important aspect of this model is that crosslinking is rank dependent. This is based on solvent swelling experiments on chars made from coals of different rank. Low-rank coals start to lose their solvent swelling ability prior to significant depolymerization at temperatures as low as 200°C. Including such crosslinking in the FG-DVC model leads to predictions for low-rank coals of a highly crosslinked network and low tar amounts. The coal is described by composition parameters that are the amounts of the functional group sources. The DVC subroutine describes the overall depolymerization of the macromolecular network consisting of aromatic ring clusters connected by bridges. The subroutine employs the overall number of bridges after bridge breaking and crosslinking to compute the fragments of the coal macromolecule. Crosslinking appears to occur with evolution of both CO 2 prior to bridge breaking and CH 4 after bridge breaking. |
| Databáze: | OpenAIRE |
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