Coal conversion reactors, characteristics

DESIGN MD MODELLING OF COAL COimiRSION REACTORS (l) CHARACTERISTICS OF VARIOUS COAL CONVERSION REACTORS... 

What sets one type of coal conversion reactor from another is the reliability of performance, which depends above all on the simplicity of design. Simplicity in design would mean ease of maintenance and high availability. Other desirable characteristics in coal conversion reactors, for example in gasifier, include a capability for processing a wide variety of coals. 

Our objective was to measure the changes in the Moessbauer parameters as a function of temperature, solvent, H2 pressure and time. The first run consisted of a sample of about 300 mg/cm coal inside the reactor under 2 psi of N2 and no solvent. It was run between room temperature and 420° C, and maintained at 420°C for 10 minutes, long enough to obtain a Moessbauer spectrum. No evidence of transformation of FeS2 to pyrrhotite was detectable by Moessbauer spectroscopy. After rapidly returning the sample to room temperature a Moessbauer spectrum was taken, from which it was observed that the characteristic spectrum of FeS2 was retained with a very small amount of conversion to pyrrhotite. 

Dispersed catalysts are defined as heterogeneous catalysts flowing alrnig with the reactants in a reactor system. The residence time of catalyst and reactants are thus equivalent and consequently, a continuous renewal of the catalyst-reactant interface is afforded. They demonstrate their usefulness in case of competitive fast deactivation or when accessibility of reactants to catalyst surface is hampered by feed characteristics. This kind of situation typically correi nds to heavy feeds processing, and effectively, the use of dispersed catalysts is practically limited to coal liquefaction and petroleum residues conversion. 

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