Continuous Bench-Scale Reactor for Hydrothermal Carbonization of Manure

Hydrothermal carbonization is a process which converts wet biomass into carbon rich, energy dense solid fuel, called hydrochar, and an aqueous product. The thermodynamic properties of water change greatly in the subcritical region from 180-280 °C, and as a result, subcritical water behaves as a non-polar solvent with high ionic activity. When subjected to HTC, biomass undergoes rapid hydrolysis and produces solid hydrochar.

In this study, a bench-scale continuous HTC reactor system has been designed, constructed, commissioned, and operated. Numerous engineering challenges were encountered during design and commissioning, primarily related to instrumentation, temperature and flow control.

Results of continuous processing are presented for conversion of glucose, microcrystalline cellulose, and manure. Both solid and liquid products were tested for their physico-chemical properties and compared with the corresponding products from batch process generated in a 2L batch Parr reactor. Feasibility of continuous hydrothermal processing is established.