Life cycle assessment and nutrient analysis of various processing pathways in algal biofuel production.
This study focuses on analyzing nutrient distributions and environmental impacts of nutrient recycling, reusing, and discharging in algal biofuels production. The three biomass conversion pathways compared in this study were: hydrothermal liquefaction technology (HTL), hydrothermal hydrolysis pretreatment +HTL (HTP), and wet lipid extraction (WLE). Carbon, nitrogen, and phosphorous (C, N, P) flows were described in each pathway. A primary cost analysis was conducted to evaluate the economic performance. The LCA results show that the HTP reduced life cycle NOxemissions by 10% from HTL, but increased fossil fuel use, greenhouse gas emissions, and eutrophication potential by 14%, 5%, and 28% respectively. The cost of per gallon biodiesel produced in HTP was less than in HTL. To further reduce emissions, efforts should be focused on improving nutrient uptake rates in algae cultivation, increasing biomass carbon detention in hydrothermal hydrolysis, and/or enhancing biomass conversion rates in the biooil upgrading processes.
School of Environmental and Sustainability Science, Kean University, 1000 Morris Ave., Union, NJ 07083, United States. Electronic address: dmu@kean.edu.
Dongyan
D
Mu
Department of Bioproducts and Biosystems Engineering and Center for Biorefining, University of Minnesota, 1390 Eckles Ave., St. Paul, MN 55108, United States. Electronic address: ruanx001@umn.edu.
Roger
R
Ruan
Department of Bioproducts and Biosystems Engineering and Center for Biorefining, University of Minnesota, 1390 Eckles Ave., St. Paul, MN 55108, United States.
Min
M
Addy
School of Environmental and Sustainability Science, Kean University, 1000 Morris Ave., Union, NJ 07083, United States.
Sarah
S
Mack
Department of Bioproducts and Biosystems Engineering and Center for Biorefining, University of Minnesota, 1390 Eckles Ave., St. Paul, MN 55108, United States.
Paul
P
Chen
College of Urban and Environment Science, Central China Normal University, 152 Luoyu Rd, Hongshan Qu, Wuhan, Hubei Province 430072, China. Electronic address: yzhou@mail.ccnu.edu.cn.
Yong
Y
Zhou
D056804:Biofuels / Q000032:analysis* / Q000191:economics; D018533:Biomass; D001709:Biotechnology / Q000191:economics / Q000379:methods*; D002244:Carbon / Q000032:analysis*; D003365:Costs and Cost Analysis; D017752:Greenhouse Effect; D058086:Microalgae / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D013696:Temperature
D056804:Biofuels; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen
Algal biofuels; Hydrothermal hydrolysis; Hydrothermal liquefaction; Life cycle assessment (LCA); NO(x) emissions