Ceramic Membrane Enhanced Two-Stage Hydrothermal Liquefaction for Simultaneous Biofuels and Biochemicals from Liquid Wastes

From a recent DOE EERE report, approximately 50 million dry tons of organic waste is available in the US for upgrading into renewable fuels (and chemicals) equivalent to nearly 7,300 MMGGE.These wastes include inedible fats and greases, food and beverage waste waters, livestock manures, municipal wastewater, and the organic fraction of municipal solid wastes. Conversion of these feedstocks into renewable bio-fuels offers a range of economic and environmental advantages and hence represents a significant opportunity for new market development. Hydrothermal liquefaction (HTL) is a promising conversion technology for these wet waste streams (relative to pyrolysis, gasification, etc.). However, although technical feasibility/potential has been shown, economic viability is still a challenge and several technology gaps in the scale-up to commercial scale continuous processing are evident xxx.Further, these wastes are widely distributed throughout the US (and world) requiring technology that is modular and adaptable, with regard to cost and complexity, to scales well below conventional petroleum refineries. As a solution to these problems, MPT proposes to integrate its high performance ceramic membranes into the conventional HTL technology. Significant processing cost savings are achieved due to surprising synergies that develop between these technologies. For instance, higher added value biochemicals and biocrude are simultaneously produced while biochar and waste gas production is reduced. Hence, overall carbon yield is significantly enhanced from ~45% to >65%. Further, the innovative water management strategy that the ceramic membranes enable also offers surprising synergies with HTL technology. These include simplified final product separation, improved thermal efficiency, lower energy consumption, and reduced capital cost. Based upon these factors, preliminary technoeconomic analysis suggests biofuel/biochemicals production cost can be pushed below $2/gge with the proposed approach, making the biofuel cost competitive with petroleum-based fuels. Further, this significant cost reduction as well as the modular and simple design makes it suitable for small scale distributed processing. During the Phase I program we will be conducting bench scale membrane enhanced hydrothermal liquefaction of sewage sludge to demonstrate the proposed concept, develop initial operating conditions, show the potential product yield and quality improvement, and establish the technoeconomic base case. This information will be used to establish the program technical approach in the Phase II pilot scale demonstration.