An engineering and economic viability assessment of converting municipal sewage sludge to biocrude via hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG)

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University of New Brunswick


The economic feasibility of a combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) process using municipal sewage sludge (MSS) as a feedstock was investigated. A predictive economic model was prepared to determine the areas within the process with the largest economic influence of the design. Laboratory experiments were focused on varying the temperature (280-320°C), residence time (10-40 minutes), and feedstock solids content (5-20wt%) of a batch HTL reaction using local MSS samples. Data from the experiments were input into the model to provide Chief Defense Contractors Inc. an engineering assessment of the proposed process. Economic results indicate that with sufficient feedstock/product flow there exists several scenarios with positive net present values. Experimental data suggests that higher operating temperatures and feedstock solids contents are favourable towards the conversion of carbon from MSS to biocrude.