Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
J Environ Manage. 2017 Dec 1;203(Pt 3):988-998. doi: 10.1016/j.jenvman.2017.03.005. Epub 2017 Mar 8.
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.
燃煤电厂是二氧化碳的主要固定排放源，环境约束要求采用减排技术。虽然碳捕集与封存是最成熟的途径，但它会对发电造成严重的经济损失。相比之下，碳捕集与利用则可以通过将二氧化碳转化为有价值的产品来实现货币化，从而降低这种经济损失。本工作评估了一条由 Chlorella pyrenoidosa 进行二氧化碳生物捕集，以及利用所得生物质作为微藻生物炼制原料的途径；将碳捕集与封存途径作为参考技术进行评估。综合方案包括：(a) 在光生物反应器中进行二氧化碳生物捕集，(b) 从部分生物质中提取油，(b) 气化剩余生物质以获得生物合成气，以及 (c) 将生物合成气转化为甲醇。根据两种途径（碳捕集与封存和生物炼制）的过程模拟得出的质量和能量平衡，估算了资本和运营支出。生物炼制的资本支出高 6.7 倍，而运营支出低 0.45 倍，只有这条途径才有收入，收入/运营支出比为 1.6。光生物反应器占生物炼制资本支出的五分之一，占地面积约为 1000 公顷，是该生物炼制技术和经济可行性的最大障碍。生物炼制和碳捕集与封存途径的二氧化碳捕集效率分别为 73%和 48%，捕集成本分别为 139 美元/吨和 304 美元/吨。此外，生物炼制在所有评估的环境影响指标方面都具有卓越的性能。
