Gasification of real MSW-derived hydrochar under various atmosphere and temperature

The hydrothermal carbonization could improve the fuel quality of municipal solid waste (MSW), in terms of water content reduction, chlorine removal, and energy densification. The chlorine content plays a significant role in determining whether the derived hydrochar is suitable as a fuel or chemical product. Many works focus on the chlorine behavior and fuel quality of hydrochar. However, few works focus on the gasification characteristics of real MSW-derived hydrochar. In this work, the hydrochar derived from real MSW employing hydrothermal treatment were gasified under various temperatures (600-1000 degrees C) and atmospheres (Air, CO2/O-2 and steam/O-2), with gas and tar analyzed by GC and GC MS, respectively. The results showed that the hydrothermal treatment could remove 90.5 % chlorine of the MSW at an HTC temperature of 220 degrees C for 30 min. The syngas quality was improved whereas the tar yield was generally reduced with the reaction temperature, independent on the atmosphere. The H-2, CO and CH4 yield was increased gradually, while the CO2 yields kept decreasing with the gasification temperature ranging from 600 to 900 degrees C. The highest H-2 yield occured in the steam/O-2 gasification, resulting in the highest H-2/CO ratio of 4.58 at a gasification temperature of 1000 degrees C. The tar yield in the air gasification was the maximum, while it was the minimum in the steam/O-2 gasification. The carbon conversion rate was increased with the gasification temperature. 900 degrees C was supposed to be a suitable operating window for obtaining gas with high H-2 concentration and heating value. All these results indicated that the hydrothermal carbonization (HTC) coupled with gasification was an effective approach to produce hydrogen-rich gas from MSW. And these findings might be helpful for the design and further optimization MSW thermochemical conversion process.