Design, modeling and characterization of an entrained flow reactor for pyrolysis/gasification of coal and biomass

Accurate determination and description of chemical kinetics of solid fuels during combustion/gasification is important to describe with accuracy their subsequent high-temperature chemistry, but also for commercial system design and optimization. Generally laboratory scale reactors are used to determine the kinetics. A high-temperature, high-pressure entrained flow reactor is being built at the Pennsylvania State University to study the pyrolysis and gasification kinetics, mineral matter transformations and interactions of coal and biomass ash with refractory materials. This paper describes the design, modeling, and construction details of the reactor system. A coal and biomass feeder to feed the fuel into a high-pressure unit has been designed and built in house. The feeder has been tested for both coal and biomass of various particle sizes. The flow of particles in the feeder is controlled by a vertical auger. The feeder is able to achieve the maximum feed rate of 1g per minute of switch grass and 2.3 g per minute of coal with 10 L per minute of transport gas. No segregation of particles is observed when feeding mixtures of coal and biomass. The main reactor tube consists of a ceramic tube of 63 mm ID and 700 mm in length. The gas flow and the heat transfer simulations in the reactor were carried out using COMSOL software. The pyrolysis gasification modeling and simulation was carried out using Ansys-Fluent software for separate feeds of coal and biomass. The modeling and simulation results for coal and biomass are presented and contrasted with the experimental results carried out in the reactor. The calculated residence time for fuels in the reactor is 0.5 s and 0.7 s for coal and biomass particles respectively. Some recirculation of particles was observed in the simulation results.