AQUATIC BIOMASS AND CARBON-DIOXIDE TRAPPING
AQUATIC BIOMASS AND CARBON-DIOXIDE TRAPPING
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DOI：
10.1016/0196-8904(93)90048-f
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发表时间：
1993-09-01
影响因子：
10.4
通讯作者：
ZEILER, KG
中科院分区：
文献类型：
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作者：
BROWN, LM;ZEILER, KG
作为可再生生物质来源的微藻生长技术可应用于柴油燃料替代品（生物柴油）的生产。微藻之所以令人感兴趣，是因为它们的高生长速率和对不同环境条件的耐受性，并且因为它们产生的油（脂质）可以被提取并转化为替代石油燃料。预计的全球气候变化为这种方法提供了第二个重要的理由。气候变化与大气中过量二氧化碳的积累有关。发电厂燃烧化石燃料是二氧化碳过量的主要原因。由于微藻生长的主要营养物质是二氧化碳，因此微藻生物质农场的运作已成为寻求缓解全球气候变化的替代方法的一个有希望的候选者。通过微藻生产柴油燃料需要非常大量的二氧化碳作为营养物。在微藻燃料农场与化石燃料工厂协同运作以从烟道气中洗涤二氧化碳的地区，二氧化碳的释放可以显著减少。 如果微藻用于生产燃料，大量培养设施可将发电厂每百万Btu的二氧化碳排放量减少约50%。例如，虽然煤通常被认为是污染最严重的化石燃料，但将微藻池与燃煤发电厂结合起来，将使这种化石燃料的污染程度低于现有的石油和天然气发电厂。燃油和燃气发电厂也可以实现类似的优势。如果商品化学品是从藻类而不是燃料中生产的，那么二氧化碳的净减少量就会大得多。日用化学品可用于生产建筑材料等长期使用的产品。在光合生物中，微藻是最具生产力的二氧化碳使用者，与高等植物相比，每片土地可以固定更多的二氧化碳。此外，高等植物和树木的最大生产力仅限于土壤、水和气候最好的地区（主要是热带地区）。植物叶片存在于空气环境中，并且经受大量的蒸发水分损失，这直接抑制光合作用过程（二氧化碳吸收）。大量培养中的微藻不受这种光合作用抑制，因为培养物的水含量可以通过适当的工程控制，并且如果需要可以使用盐水。这种差异是微藻吸收二氧化碳的能力比植物高几倍的基础。这项技术的初步应用设想在美国西南部的沙漠地区，因为该地区提供高太阳辐射，并提供平坦的土地，几乎没有竞争用途（因此土地成本低）。此外，该地区还有大量的咸水层，但它们的用途很少，相互竞争。这些可以为许多种类的微藻的生长提供合适的、低成本的培养基。
The technology for growing microalgae as a renewable biomass source can be applied to the production of a diesel fuel substitute (biodiesel). Microalgae are of interest because of their high growth rates and tolerance to varying environmental conditions, and because the oils (lipids) they produce can be extracted and converted to substitute petroleum fuels. Projected global climate change provides a second important rationale for this approach. Climate change has been linked to the accumulation of excess carbon dioxide in the atmosphere. The burning of fossil fuels in power plants is the primary contributor to excess carbon dioxide. Inasmuch as the primary nutrient for microalgal growth is carbon dioxide, operation of microalgal biomass farms has emerged as a promising candidate in the search for alternative approaches to ameliorate global climate change. The production of diesel fuel by microalgae requires very large quantities of carbon dioxide as a nutrient. In areas where microalgae fuel farms operate in tandem with fossil fuel plants to scrub carbon dioxide from flue gases, the release of carbon dioxide could be significantly reduced. If the microalgae are used to produce fuel, a mass culture facility reduces by approximately 50% the carbon dioxide emissions from the power plant per million Btu delivered. For example, although coal is ordinarily considered to be the most polluting fossil fuel on the basis of carbon dioxide emitted per amount of energy produced, the incorporation of microalgal ponds with a coal-fired plant would make this fossil fuel less polluting than existing oil- and natural-gas-fired plants. Similar advantages can be achieved for oil- and gas-fired plants. If commodity chemicals are produced from algae instead of fuels, the net carbon dioxide reduction is significantly greater. Commodity chemicals can be used to produce goods with long-term uses such as building materials. Such uses would result in the sequestering of carbon dioxide for long periods.Of the photosynthetic organisms, microalgae are the most productive carbon dioxide users and can fix greater amounts of carbon dioxide per land area than higher plants. Also, maximum productivities of higher plants and trees are restricted to areas with prime soil, water, and climate (primarily the tropics). Plant leaves exist in an aerial environment and are subject to large evaporative moisture losses, which directly inhibit the process of photosynthesis (carbon dioxide uptake). Microalgae in mass culture are not subject to such photosynthetic inhibition because the water content of the culture can be controlled by proper engineering, and saline water can be used if necessary. This difference is the basis for the several-fold higher carbon dioxide absorption capacity of microalgae compared to plants.Initial application of this technology is envisioned for the Desert Southwest of the United States because this area provides high solar radiation and offers flat land that has few competing uses (hence low land costs). Also, there are large saline aquifers with few, competing uses in the region. These could provide a suitable, low-cost culture, medium for the growth of many species of microalgae.