Static model of coal pyrolysis in a circulating fluidised-bed reactor

• Published in: Applied energy Vol. 74; no. 3; pp. 455 - 465
• Main Author: Sciazko, Marek
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.03.2003; Elsevier Science; Elsevier
• Series: Applied Energy
• Subjects: Applied sciences; Energy; Exact sciences and technology; Fluidisation; Fuel processing. Carbochemistry and petrochemistry; Fuels; Gasification; Modelling; Pyrolysis; Pyrolysis Gasification Fluidisation Modelling; Solid fuel processing (coal, coke, brown coal, peat, wood, etc.); Pyrolysis; Gasification; Modelling; Fluidisation; Circulating fluidized bed; Lignite; Subbituminous coal; Experimental study; Modeling; Bituminous coal
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/S0306-2619(02)00200-3

Four different coals were investigated: two sub-bituminous, one bituminous and lignite, which were processed in the temperature range 750–950 °C. The heat for pyrolysis was generated by partial gasification of the char produced. Air was used as the gasifying medium with amounts of 0.6–1.5 m 3/kg of coal, depending on the required gasification-temperature. Two sequential phenomena were taken into account: char gasification and coal devolatilisation in respect of temperature. The experimental data on carbon dioxide and monoxide concentrations in a LCV gas produced were used for the correlation of Boudouard's equilibrium and the data on carbon burn-off and final volatile matter content in char were used for the solid-products yield. The equations for the quasi-equilibrium state were developed and calculated values were compared with the measurements. The model takes into account the equations developed and the total energy-balance assuming the heat losses of the experimental system. The investigated coal throughput amounted to 200–300 kg/h depending on the coal properties. Process characteristics were discussed, namely: the effect of air/coal ratio on the pyrolysis temperature; char and gas yield, volatile matter and ash content in a char; as well as the gas calorific value.