Study On Flow Field Distribution And Coal Gasification Reactivity In A Two-stage Gasifier

In order to understand the flow field distribution and coal reaction law in the two-stage combined gasifier, firstly, the flow field distribution of a two-stage gasifier was measured on a cold model, the results show that gas blowing form into the first stage of the gasifier has no effect on pressure drop of the second stage. Pressure drop of the fixed bed linearly increases with the bed height while decreases gradually with the bed porosity. Increasing bed height and reducing bed porosity could both reduce the average residence time of gas in the gasifier.Secondly, the influence of calcium nitrate on coal char gasification reactivity and the effective gas generation law when coal char gasified with the mixture of stream and CO? were studied on a fixed bed furnace. The results show that the amount of effective gas when Inner Mongolia lignite char gasified with stream and CO2are nearly the same, but when the char gasified with the mixture of stream and CO2(ratio is1:1), the amount of effective gas increases in a extend. With the reduction of CO2content in the mixture, CO generation decreases while H2generation increases. The effective gas generation would increase obviously when the stream content in mixture is more than80%.Finally, the influences of different conditions on two-stage gasification process were studied. The results show that the optimal size range of coal char is15-20mm size. Coal types and composition of syngas from the first stage both impact on the LHV of syngas and CO2conversion rate, coal conversion in the fixed bed would be different because of the different experimental conditions.