Techno-economic evaluation of microalgae harvesting and dewatering systems
Techno-economic evaluation of microalgae harvesting and dewatering systems
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DOI：
10.1016/j.algal.2017.11.038
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发表时间：
2018-04-01
影响因子：
5.1
通讯作者：
van Boxtel, A. J. B.
中科院分区：
文献类型：
--
作者：
Fasaei, F.;Bitter, J. H.;van Boxtel, A. J. B.
微藻生物质通过两个主要工艺步骤加工成产品：1）收获和脱水;以及2）提取、分级和转化。收获和脱水单元操作的性能通常用定性术语表示，如“高能耗”和“低运营成本”。此外，设备被分析为独立的单位业务，在业务链中不相互作用。本文对不同的大型收获脱水系统进行了定量的技术经济分析，重点是处理成本、能源消耗和资源回收。收获和脱水被认为是一个单一的操作和顺序操作的组合。经济评估表明，对于来自开放式培养系统的稀溶液，操作成本和能量消耗分别在0.5-2（sic）·kg（-1）藻类和0.2-5（kWh.kg（-1）藻类的范围内。通过絮凝对稀释系统进行收集和脱水，可实现最低的能源需求。然而，由于所需的化学品和絮凝剂的损失，这些系统的成本与机械收获系统相同。对于封闭式培养系统，操作成本降低到0.1-0.6（sic）·kg（-1）藻类，能量消耗降低到0.1- kWh.kg（-1）藻类。对于所有收割和脱水系统来说，劳动力对总成本有很大影响。尽管相关的投资成本较高，但高水平的自动化可以降低总成本。分析表明，如果操作达到高生物质浓度，则单步操作可以是令人满意的。从经济角度来看，两步操作，如加压过滤，然后是螺旋板技术或离心，是有吸引力的，就像絮凝，然后是膜过滤和螺旋板技术或离心的精加工步骤的操作链一样。
Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like "high energy consumption" and "low in operational cost". Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5-2 (sic).kg(-1) algae and 0.2-5 kWh.kg(-1) of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1-0.6 (sic).kg(-1) algae and the energy consumption to 0.1-0.7 kWh.kg(-1) algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation.