title: Carbon dioxide utilization in a microalga-based biorefinery: Efficiency of carbon removal and economic performance under carbon taxation.
abstract: Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts.
authors.affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: igorwg@ufrj.br.
authors.forename: Igor Lapenda
authors.initials: IL
authors.lastname: Wiesberg
authors.affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: george.victor@poli.ufrj.br.
authors.forename: George Victor
authors.initials: GV
authors.lastname: Brigagão
authors.affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: jlm@eq.ufrj.br.
authors.forename: José Luiz
authors.initials: JL
authors.lastname: de Medeiros
authors.affiliation: Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: ofelia@eq.ufrj.br.
authors.forename: Ofélia
authors.initials: O
authors.lastname: de Queiroz Fernandes Araújo
mesh_terms: D018533:Biomass; D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide; D002708:Chlorella / Q000737:chemistry*; D058086:Microalgae / Q000737:chemistry*; D011210:Power Plants / Q000191:economics*; D013660:Taxes
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: Biomass gasification; Biorefinery; Carbon capture and storage; Carbon dioxide utilization; Methanol synthesis; Microalgae