title: Life cycle assessment of biodiesel production from algal bio-crude oils extracted under subcritical water conditions.
abstract: A life cycle assessment study is performed for the energy requirements and greenhouse gas emissions in an algal biodiesel production system. Subcritical water (SCW) extraction was applied for extracting bio-crude oil from algae, and conventional transesterification method was used for converting the algal oil to biodiesel. 58MJ of energy is required to produce 1kg of biodiesel without any co-products management, of which 36% was spent on cultivation and 56% on lipid extraction. SCW extraction with thermal energy recovery reduces the energy consumption by 3-5 folds when compared to the traditional solvent extraction. It is estimated that 1kg of algal biodiesel fixes about 0.6kg of CO2. An optimized case considering the energy credits from co-products could further reduce the total energy demand. The energy demand for producing 1kg of biodiesel in the optimized case is 28.23MJ.
authors.affiliation: Chemical & Materials Engineering Department, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Sundaravadivelnathan
authors.initials: S
authors.lastname: Ponnusamy
authors.affiliation: Chemical & Materials Engineering Department, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Harvind Kumar
authors.initials: HK
authors.lastname: Reddy
authors.affiliation: Chemical & Materials Engineering Department, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Tapaswy
authors.initials: T
authors.lastname: Muppaneni
authors.affiliation: Economics, Applied Statistics & International Business Department, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Cara Meghan
authors.initials: CM
authors.lastname: Downes
authors.affiliation: Chemical & Materials Engineering Department, New Mexico State University, Las Cruces, NM 88003, USA. Electronic address: sdeng@nmsu.edu.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Deng
mesh_terms: D056804:Biofuels; D019149:Bioreactors; D057486:Carbon Cycle / Q000502:physiology*; D058572:Carbon Footprint / Q000706:statistics & numerical data*; D003246:Conservation of Energy Resources / Q000379:methods* / Q000706:statistics & numerical data; D004951:Esterification; D058086:Microalgae / Q000378:metabolism*; D014867:Water
chemical_list: D056804:Biofuels; D014867:Water
keywords: Biodiesel; Greenhouse gas emissions; LCA; Life cycle assessment; Subcritical water extraction