Numerical Simulation Of Horizontal Cyclone Gasification And Kinetic Study On Char Reaction

There are abundant reserves of low rank coal in China. As a representative, Zhundong Coal is rich in moisture and volatile, reducing combustion and gasification efficiency in its direct utilization. According to the composition and structural characteristics of low rank coal, we can extract the volatile through pyrolysis firstly, then, gasify the remaining char to achieve its cascade transformation and improve the utilization of resources.In this paper, we brought up a new furnace with horizontal cyclone gasification methods for the the gasification of low rank coal. First, experiments of low rank coal gasification under different pressures were conducted by compressed TGA. The experimental results were used to amend the gasification kinetics models. Numerical simulation of coal gasification coupled with ash deposition sub-models were carried out.Results of coal gasification experiments under different pressures showed that the pressurized gasification reaction rate can increase to some extent, but its promoting effects has a limit. Isothermal methods were used to analyze the Zhundong Coal gasification kinetics, found in good reactivity under pressure, and the activation energy was low.Results of simulation showed that the necking diameter and length determines the reflux in the gasifier. Nozzle structures have an important impact on velocity field, pressure field, turbulent flow structures. After the coal particles sprayed into the future, the maximum velocity was lower than single-phase flow, with a loss of momentum and an improvement of the average turbulence intensity.Coupled simulation of ash deposition and gasification hot models showed the particle deposition rate was larger in the middle of the gasifier. After the liquid flow was steady, the thickness can reach several millimeters, the velocity can reach several millimeters per second. The high temperature zone moved ahead and the CO2 content reduced considering the particle deposition. The total heat flux density was much lower considering the heat resistance of ash. After the amendment of reaction kinetics parameters, there was a slight increase in carbon conversion rate and carbon monoxide components.