Entrained Flow Coal Gasifier Research Articles

Modeling and simulation of an entrained flow coal gasifier

AbstractA mathematical model has been developed to simulate the Texaco downflow entrained‐bed pilot‐plant gasifier using coal liquefaction residues and coal‐water slurries as feedstocks. This model describes the physical and chemical processes occurring in an entrained coal gasifier. The gasification kinetics describes different complex reactions occurring in the gasifier and the hydrodynamics describes mass, momentum and energy balances for solid and gas phases. Temperature, concentration and velocity profiles along the reactor height were obtained by solving the mass, momentum and energy balances. Parameter studies were made to provide a better understanding of the reactor performance for various inlet feed conditions utilizing the model.

Comparison of Coal Gasification and Combustion Residues

Slags produced from the entrained flow gasification and cyclonefurnace combustion of Pittsburgh seam coal are morphologically similar and exhibit similar leaching behavior. Both wastes consist predominantly of dense glassy shards with low specific surface area (<1m2/g). Based on aqueous extraction and inorganic analyses according to the extraction procedure specified under the Resource Conservation and Recovery Act (RCRA), none of the combustion or gasification solid wastes examined in this study would be classified as hazardous under current federal regulations. The concentrations of most trace elements in RCRA and other batch extracts of the gasification slag and combustion bottom wastes were below current or proposed drinking water levels. In contrast, arsenic, cadmium, chromium, selenium, zinc, manganese, copper, and sulfate in batch extracts of two combustion fly ashes from Pittsburgh coal exceeded drinking water criteria. These results suggest that slags from entrained flow coal gasification should not require solid waste management practices substantially different from those currently used for coal combustion solid wastes.

Modeling pulverized coal conversion in entrained flows

AbstractA detailed description of pulverized coal conversion in one‐dimensional entrained flows has been formulated and correlated to hydrogasification data from the Rockwell International Flash Hydropyrolysis (FHP) reactor using bituminous coals. This analysis contains physical and chemical descriptions which have not been included in previous mathematical models. These descriptions provide further important insights into the nature of entrained flow coal gasification.

Scaling laws and the differential equations of an entrained flow coal gasifier

AbstractA formal order of magnitude analysis was applied to the differential equations describing mass, momentum, and energy transport in an axially translating, vortex flow field and used to determine the importance of various terms. Significant dimensionless parameters, suitable for establishing scaling laws, appear naturally from the equations. Among the important parameters are the swirl number, geometric scale ratio, Froude number, and particle loading ratio. These parameters were combined to establish rules for complete similarity between a model and a prototype gasifier.