Article
Evaluating the Impacts of ACP Management on the Energy Performance of Hydrothermal Liquefaction via Nutrient Recovery
Energies
(2019)
Abstract
Hydrothermal liquefaction (HTL) is of interest in producing liquid fuels from organic
waste, but the process also creates appreciable quantities of aqueous co-product (ACP) containing
high concentrations of regulated wastewater pollutants (e.g., organic carbon, nitrogen (N), and
phosphorus (P)). Previous literature has not emphasized characterization, management, or possible
valorization of ACP wastewaters. This study aims to evaluate one possible approach to ACP
management via recovery of valuable scarce materials. Equilibrium modeling was performed to
estimate theoretical yields of struvite (MgNH4PO4·6H2O) from ACP samples arising from HTL
processing of selected waste feedstocks. Experimental analyses were conducted to evaluate the
accuracy of theoretical yield estimates. Adjusted yields were then incorporated into a life-cycle energy
modeling framework to compute energy return on investment (EROI) for the struvite precipitation
process as part of the overall HTL life-cycle. Observed struvite yields and residual P concentrations
were consistent with theoretical modeling results; however, residual N concentrations were lower than
model estimates because of the volatilization of ammonia gas. EROI calculations reveal that struvite
recovery is a net-energy producing process, but that this benefit offers little to no improvement
in EROI performance for the overall HTL life-cycle. In contrast, corresponding economic analysis
suggests that struvite precipitation may be economically appealing.
Disciplines
Publication Date
Winter February 22, 2019
DOI
10.3390/en12040729
Publisher Statement
Energies is an Open Access journal published by MPDI AG.
Citation Information
Sarah Bauer, Fangwei Cheng and Lisa M. Colosi. "Evaluating the Impacts of ACP Management on the Energy Performance of Hydrothermal Liquefaction via Nutrient Recovery" Energies Vol. 12 Iss. 729 (2019) Available at: http://works.bepress.com/sarah-bauer/4/
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