Algal biofuel production requires CO₂, electricity, and process heat. Previous studies assumed CO₂ sourcing from nearby coal or natural gas power plants. This may not be viable at a large scale or for the long term. The diurnal algal growth cycle imposes additional system design challenges for CO₂ delivery. For ethanol produced by cyanobacteria in photobioreactors, we design onsite systems that provide heat, power and CO₂ (CHP‐CO₂), fueled by natural gas or biomass. Meeting the CO₂ requirement produces excess electricity, which can be sold back to the grid. The scale of the CHP‐CO₂ can be reduced by night‐time capture and refrigerated storage of CO₂. The lifecycle greenhouse gas (GHG) emissions for 1 MJ ethanol are about −19 g CO₂e for biomass CHP‐CO₂, and +31–35 CO₂e g for natural gas CHP‐CO₂ options, compared with +19 g CO₂e for the direct use of coal flue gas, and 91.3 g CO₂e for 1 MJ of conventional gasoline. This work evaluates the energy and GHG implications of onsite CHP‐CO₂ for algal ethanol production and other CO₂ sourcing options. Combined heat and power (CHP) facilities, fueled by natural gas or biomass, could be co‐located with algal ethanol production, capturing and utilizing carbon dioxide to make biofuel, and thus providing an essentially stand‐alone biofuel operation, free from the constraints of co‐location with anthropogenic sources. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

中文翻译：

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基于转基因蓝细菌的乙醇生产过程的生命周期温室气体排放量：CO2来源选择

藻类生物燃料生产需要CO ₂，电力和过程热。先前的研究假设CO _2是从附近的煤炭或天然气发电厂采购的。从长远来看，这可能不可行。昼夜藻类的生长周期对CO _2的输送提出了额外的系统设计挑战。对于由蓝细菌在光生物反应器中产生的乙醇，我们设计了现场系统，该系统以天然气或生物质为燃料提供热量，电能和CO ₂（CHP-CO ₂）。满足CO ₂要求会产生多余的电能，可以将其回卖给电网。CHP-CO ₂的规模可通过夜间捕获和冷藏存储的CO来减少₂。1 MJ乙醇的生命周期温室气体（GHG）排放量，生物质CHP-CO ₂约为−19 g CO ₂ e，天然气CHP‐CO ₂选件约为+ 31–35 CO ₂ e g ，而+19 g CO ₂ e用于直接使用煤烟气，91.3 g CO ₂ e用于1 MJ常规汽油。这项工作评估了现场CHP-CO ₂对藻类乙醇生产和其他CO ₂的能量和温室气体的影响采购选项。天然气或生物质为燃料的热电联产（CHP）设施可与藻类乙醇生产并置在一起，捕获和利用二氧化碳制成生物燃料，从而提供不受限制的基本独立的生物燃料运营与人为来源共处一地。©2020年化学工业协会和John Wiley＆Sons，Ltd