Low temperature reaction path for coal liquefaction
Conference
·
· Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States)
OSTI ID:5170980
Onset of a solvent-coal reaction occurs in the 200-300/sup 0/C temperature range. The temperature and extent of this reaction are dependent on the coal and solvent. In this initial reaction, THF soluble products increase but solvent is lost indicating formation of a THF soluble, coal-solvent reaction product. This reaction product, defined in the preasphaltene or asphaltol compounds, results in high viscosity products - possibly gels. Kinetic studies show the liquefaction mechanisms can be represented by parallel reactions of coal to preasphaltenes, asphaltenes, oils and gases. However, these data show coal itself does not undergo thermosolvolysis at temperatures to 300/sup 0/C and free radical processes need not be invoked to explain the reactions observed in the 200-300/sup 0/C range. The data do suggest an initial series reaction of Coal + Solvent ..-->.. Preasphaltenes. The hydrogen donating capability of the solvent does not appear to be critical at this stage, but functional groups that can interact with the coal and cause swelling are important. This initial series reaction is also indicated in the short time, continuous reactor results, where the preasphaltene content rises along with a solvent loss early in the reaction; subsequent decrease in preasphaltene content is accompanied by an increase in oil and asphaltene concentrations. Preasphaltene chemistry needs further clarification. The extent, and possibly type, of coal-solvent interaction changes with temperature. Only about 30% THF conversion occurs at low temperatures with 80 to 95% conversion occurring over 400/sup 0/C.
- Research Organization:
- Sandia Lab., Albuquerque, NM
- OSTI ID:
- 5170980
- Report Number(s):
- CONF-790917-P3
- Conference Information:
- Journal Name: Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States) Journal Volume: 24:3
- Country of Publication:
- United States
- Language:
- English
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