Wei Huo

Study on CO2 gasification reactivity and physical characteristics of biomass, petroleum coke and coal chars

Gasification reactivities of six different carbonaceous material chars with CO2 were determined by a Thermogravimetric Analyzer (TGA). Gasification reactivities of biomass chars are higher than those of coke and coal chars. In addition, physical structures and chemical components of these chars were systematically tested. It is found that the crystalline structure is an important factor to evaluate gasification reactivities of different chars and the crystalline structures of biomass chars are less order than those of coke and coal chars. Moreover, initial gasification rates of these chars were measured at high temperatures and with relatively large particle sizes. The method of calculating the effectiveness factor η was used to quantify the effect of pore diffusion on gasification. The results show that differences in pore diffusion effects among gasification with various chars are prominent and can be attributed to different intrinsic gasification reactivities and physical characteristics of different chars.

Rheology and Viscosity Prediction of Bituminous Coal Slag in Reducing Atmosphere

The high-temperature rheology of bituminous coal slag in the reducing atmosphere was investigated in this study. The characteristics of slag sample were analyzed by multi-techniques. The rheological measurement of the slag was carried out by a high-temperature rheometer at temperatures of 1360-1460℃. The effects of the shear rate and temperature on the rheological property of the slag were studied. The volume fractions of crystallize particles and mineral matters variation were predicted by thermodynamic software FactSage. The results show that the viscosity and shear stress of the slag increase with decreasing temperature at the constant shear rate. When the volume fraction of the crystallize particles is less than 10%, the slag behaves as a Newtonian fluid. When the volume fraction of the crystallize particles is more than 15%, the slag viscosity decreases with increasing shear rate. The non-Newtonian fluid behavior of slag is illustrated by shear thinning behavior and thixotropic behavior. With decreasing temperature, the shear thinning behavior becomes increasingly significant. In addition, the viscosity prediction model basing on S2 model and Einstein-Roscoe model was established.

Reaction Kinetic Analysis of Bituminous Coal Char Gasified by CO2

CO2-gasification behaviors of Shenfu bituminous coal from China were investigated by thermogravimetric analyzer within the temperature range of 1173–1323 K, and the pressure from 0.1 to 3.0 MPa. The effects of the temperature and pressure on the CO2 gasification of Shenfu char and the relationship between the gasification rate and gasification time in reactor were analyzed. It is found that the reaction rate presents normal distribution with gasification time and a normal distribution model is proposed to fit the kinetics data. Compared with the random pore model, the normal distribution model can be used to describe the gasification rate varying with gasification time at different temperature and pressure. The gasification time tm for maximum gasification rate obeys the following equation as the function of reaction temperature: . rm, r0 were calculated by a normal distribution model following Arrenius law.