Performance Simulations for Co-Gasification of Coal and Methane
In the process under development,coal suspended in mixtures of CH4,H2,and steam is rapidly heated to temperatures above 1400℃ under 5-7 MPa for at least one second.The coal first decomposes into volatiles and char while CH4 is converted into CO/H2 mixtures.Then the char is converted into CO/H2 mixtures via steam gasification on longer time scales,and into CH4 via hydrogasification.Throughout all stages,homogeneous chemistry reforms all intermediate fuel components into the syngas feedstock for methanol synthesis.Fully validated reaction mechanisms for each chemical process were used to quantitatively interpret a co-gasification test series in SRIs lab-scale gasification facility.Homogeneous reforming chemistry generates equilibrium gas compositions at 1500℃ in the available transit time of 1.4s,but not at any of the lower temperatures.Methane conversion in the gas phase increases for progressively hotter temperatures,in accord with the data.But the strong predicted dependence on steam concentration was not evident in the measured CH4 conversions,even when steam concentration was the subject test variable.Char hydrogasification adds CH4 to the product gas stream,but this process probably converts no more than 15 to 20％ of the char in the lab-scale tests and the bulk of the char is converted by steam gasification.The correlation coefficient between predicted and measured char conversions exceeded 0.8 and the std.dev.was 3.4％,which is comparable to the measurement uncertainties.The evaluation of the predicted CH4 conversions gave a std.dev.greater than 20％.Simulations of commercial conditions with realistic suspension loadings and no diluents in the feed gave slightly lower conversions of both CH4 and coal,because hydrogasification accounts for more of the char conversion,and occurs at rates slower than for steam gasification.
Coal Gasification Simulation Methane
Stephen Niksa J.-P.Lim D.del Rio Diaz Jara D.Eckstrom D.Steele R.Malhotra R.B.Wilson
Niksa Energy Associates LLC,Belmont,CA,94002 USA hemistry and Chemical Engineering Dept,SRI International,Menlo Park,CA 94025 USA Chemistry and Chemical Engineering Dept,SRI International,Menlo Park,CA 94025 USA
国际会议
The 7th International Symposium on Coal Combustion(第七届国际煤燃烧学术会议)
哈尔滨
英文
461-465
2011-07-19（万方平台首次上网日期，不代表论文的发表时间）