Abstract

Clean and efficient electricity can be generated using an Integrated Gasification Combined Cycle (IGCC). Although IGCC is typically used with coal, it can also be used to gasify other carbonaceous species like biomass and petroleum coke. It is important to understand the pyrolysis and gasification of these species in order to design commercial gasifiers and also to determine optimal conditions for operation. High heating-rate (100,000 K/s) pyrolysis experiments were performed with biomass (sawdust) in BYU's atmospheric flat-flame burner reactor at conditions ranging from 1163 to 1433 K with particle residence times ranging from 23 to 102 ms. Volatile yields and mass release of the sawdust were measured. The measured pyrolysis yields of sawdust are believed to be similar to those that would occur in an industrial entrained-flow gasifier since biomass pyrolysis yields depend heavily on heating rate and temperature. Sawdust pyrolysis was modeled using the Chemical Percolation Devolatilization model assuming that biomass pyrolysis occurs as a weighted average of its individual components (cellulose, hemicellulose, and lignin). Thermal cracking of tar into light gas was included using a first-order kinetic model. The pyrolysis and CO2 gasification of petroleum coke was studied in a pressurized flat-flame burner up to 15 atm for conditions where the peak temperature ranged from 1402 to 2139 K. The measured CO2 gasification kinetics are believed to be representative of those from an entrained-flow gasifier since they were measured in similar conditions of elevated pressure and high heating rates (100,000 K/s). This is in contrast to the gasification experiments commonly seen in the literature that have been carried out at atmospheric pressure and slow particle heating rates. The apparent first-order Arrhenius kinetic parameters for the CO2 gasification of petroleum coke were determined. From the experiments in this work, the ASTM volatiles value of petroleum coke appeared to be a good approximation of the mass release experienced during pyrolysis in all experiments performed from 1 to 15 atm. The reactivity of pet coke by CO2 gasification exhibited strong pressure dependence.

Degree

College and Department

Ira A. Fulton College of Engineering and Technology; Chemical Engineering

Rights

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