HYDROTHERMAL PROCESSING OF SWINE MANURE INTO OIL USING A CONTINUOUS REACTOR SYSTEM: DEVELOPMENT AND TESTING

Hydrothermal processing of swine manure is a novel technology that has shown very promising results in treating waste and producing oil. A batch hydrothermal process system that was previously developed at the University of Illinois at Urbana-Champaign successfully converted up to 70% of swine manure volatile solids into oil and reduced manure chemical oxygen demand by up to 75%. Since a continuous system is more applicable for scale-up operations, a small-scale continuous hydrothermal process (CHTP) reactor system was developed to evaluate the technical feasibility of the continuous-mode process. The CHTP reactor system was composed of a high-pressure slurry feeder, a process gas feeder, a continuous stirred tank reactor, a product separation vessel, and process controllers. It had a capacity to process up to 48 kg of manure slurry per day. The CHTP reactor system was successfully operated continuously for up to 16 h per test. Oil yields ranging from 62.0% to 70.4% were achieved. The heating value of the oil product ranged from 25,176 kJ/kg to 31,095 kJ/kg with the highest value at T = 305°C, P = 10.3 MPa, and RT = 80 min.