Hydrothermal Liquefaction (HTL) and Catalytic Hydrothermal Gasification (CHG) proof-of-concept bench-scale tests were performed to assess the potential of hydrothermal treatment for handling municipal wastewater sludge. HTL tests were conducted at 300-350?C and 20 MPa on three different feeds: primary sludge, secondary sludge, and digested solids. Corresponding CHG tests were conducted at 350?C and 20 MPa on the HTL aqueous phase output using a ruthenium based catalyst. Biocrude yields ranged from 25-37%. Biocrude composition and quality were comparable to biocrudes generated from algae feeds. Subsequent hydrotreating of biocrude resulted in a product with comparable physical and chemical properties to crude oil. CHG product gas methane yields on a carbon basis ranged from 47-64%. Siloxane concentrations in the CHG product gas were below engine limits. The HTL-CHG process resulted in a chemical oxygen demand (COD) reduction of > 99.9% and a reduction in residual solids for disposal of 94-99%.
Revised: February 22, 2019 |
Published: April 1, 2018
Citation
Marrone P.A., D.C. Elliott, J.M. Billing, R.T. Hallen, T.R. Hart, P. Kadota, and J.C. Moeller, et al. 2018.Bench-Scale Evaluation of Hydrothermal Processing Technology for Conversion of Wastewater Solids to Fuels.Water Environment Research 90, no. 4:329-342.PNNL-SA-131515.doi:10.2175/106143017X15131012152861