Abstract:
Gasification of extraction residue from coal liquefaction residue to produce hydrogen can effectively solve the disposal problem and provide the raw material hydrogen for coal direct liquefaction production plant, so as to realize the resource utilization and make full use of liquefaction residue.In this paper, a series of studies were conducted on the gasification reactivity, ash characteristics and dry powder transport characteristics of extraction residue from coal liquefaction residue.Gasification suitability was also evaluated.Based on the 3 t/d dense-phase transport and gasification pilot plant of China Energy Investment Corporation, some relevant pilot test researches were carried out, the process stability, liquid slag discharge phenomenon and gasification performance index were investigated.Moreover, based on the results of the pilot test, the effect of blending extraction residue in Shenhua Ordos coal gasification hydrogen production plant on its performance was simulated numerically.Results show that extraction residue coke exhibits a better gasification reactivity than coke does.When the content of extraction residue is lower than 20%, the raw material can be conveyed stably.Under the following conditions, that back pressure, pressure difference and pipe diameter are 4 MPa, 0.5 MPa and 25 mm, respectively.When its content exceeds 20%, the crystal structure of slag starts to crystallization, which may cause slag blockage problem in the gasification process.It was also confirmed in the pilot scale test, the serious blockage occurred at the slag outlet of gasifier when the content of extraction residue was 20%, and the gasification process was stable when the content of extraction residue was 10%.Therefore, in industrial process, the proportion of extraction residue should be controlled below 10%.The CFD analysis also shows that a 10% addition of extraction residue doesn’t have significant effect on the temperature field as well as their composition distribution.