Numerical Simulation And Analysis On Biomass Gasification Furnace

Gasifier is a core device of current centralized heating supply via biomass gasification. Development of combustor using biomass-derived gas plays an important role in industrializing application of central heating in rural districts. In this paper, the pyrolysis and dynamic characteristics of three raw materials have been researched through thermogravimetric experiments on different conditions. Experimental results show that three kinds of biomass materials have similar pyrolysis behaviors. The pyrolysis temperature has a narrow raise of 300℃to 350℃, indicating that the volatile releases fast in this stage.Numerical simulation and tests are conducted following the thermogravimetric experiments, considering gas combustion, heat transfer and fluid dynamics, the developed numerical model is solved by CFD solver (Fluent). Different working conditions of the main body of burners with different types are analyed. A good accordance of working conditions between theoretically predicted and experimentally is observed. The results illustrate that prePDF model together with k-εtwo-computing model are fit for both fluidized bed and fixed-bed. Simulation results show that CO and H2 produce mainly in the pyrolysis area. The numerical model is also useful for future design and optimization of modified gasifier.Material adaptability is also discussed for a fixed-bed gasifier, which is builted in the demonstration project in Tianjin. Simulation results show that the gasification of cotton straws and sawdust are good in the gasifier. On the other hand, experiments illustrate that optimization of the fixed-bed gasifer is needed if biomass material is husk.