Ceramic Membrane Enhanced Two-Stage Hydrothermal Liquefaction for Simultaneous Biofuels and Biochemicals from Liquid Wastes
Hydrothermal liquefaction (HTL) has emerged as a leading technology for biofuel production from wet waste streams. However, there are a range of problems, limitations, and drawbacks associated with “conventional” HTL technology for wet waste processing. Many of these problems or challenges of HTL processing can be ameliorated with the introduction of in-situ/in-process separation of intermediate biochemicals prior to biofuels production. In this Phase I project, Media and Process Technology Inc (MPT) demonstrated the use of our ceramic membrane technology at intermediate temperatures (200 to 300°C) for soluble organic “biochemicals” extraction and recovery followed by in-line high temperature HTL processing of the remaining waste biomass for “biofuels” production. In the Phase I program, the primary objective was to demonstrate that the proposed ceramic membrane enhanced HTL process, CMHTL, for valorization of wet waste biomass with biochemicals recovery at intermediate temperatures and biofuel production at conventional HTL temperatures. All of the Phase I program objectives were successfully accomplished. In the Phase I program it was demonstrated that the CMHTL process could deliver high quality high value intermediate “biochemicals”. A preliminary market for the biochemicals was identified that demonstrated at least a 5 to 10-fold improvement in value over fuel. In contrast, conventional “one-pot” HTL processing yields no biochemicals fraction, only low molecular weight organics suitable for (catalytic hydrothermal) gasification. Further, by removing these low refractory components at intermediate processing conditions in the CMHTL process, subsequent high temperature HTL processing of the remaining biomass resulted in a higher quality “biofuel” that was suitable as a No. 2 fuel oil or marine diesel oil (MDO) drop-in. Unlike the high viscosity biocrude samples described in the literature using conventional “one-pot” HTL, the biofuel generated in this project from four different wet waste sludge samples did not require hydroprocessing and displayed diesel fuel-like viscosities, high BTU content, and low sulfur content (ND to ca 400ppm). A capital and operating costs model was developed during the Phase I program using an NREL study as a template, supplemented with design and estimating capabilities of our Phase III commercialization partner. For a baseline 40 tpd dry basis CMHTL processing facility, simple capital payback in under two years and a DOE investment multiple of 62 were demonstrated. Based upon our Phase I results and TEA, a $1MM commitment from our Phase III commercialization partner as capital financing for our Phase III program kick-off and semi-works expansion. Additionally, four potential technology customers were identified that are willing to (i) make in-kind contributions during Phase II to assist in the process development via feedstock supply, field test site support, and/or analytical support and (ii) become Phase III venture partners as the network of regional CMHTL processing centers expands. Overall, the Phase I program demonstrated that the proposed CMHTL concept delivers significant processing cost savings over conventional HTL. Value added biochemicals and biocrude are co-produced while biochar and waste gas production is reduced resulting in an overall carbon yield enhancement from ~45% to >65%. Further, the innovative water management strategy that the ceramic membranes enables offers surprising synergies with conventional HTL technology. These include simplified final product separation, improved thermal efficiency, lower energy consumption, and reduced capital cost. Based upon these factors, a CMHTL based wet waste valorization system delivers reduced capital payback relative to conventional “one-pot” HTL. Hence, the technology can be applied directly to the problem of small scale distributed generation of wet waste sludges throughout the US and internationally.
- Research Organization:
- Media and Process Technology Inc
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
- DOE Contract Number:
- SC0018746
- OSTI ID:
- 1573248
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- 001
- Country of Publication:
- United States
- Language:
- English
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