The purification of synthetic and pre-treated impure glycerol from 2 generation biodiesel refineries is addressed to reduce the ash content below 1 % wt. Electrodialysis purification has been selected for its ability to selectively remove salts from the glycerol. First, synthetic glycerol-rich samples are tested to optimise cell voltage, membrane type and time on stream to achieve the target of 1 % wt. ash. After that, industrial pre-treated glycerol is used as a feed stream and compared. The comprehensive testing campaign demonstrated a recovery greater than 60 % with a glycerol purity greater than 82.2 % (wet and 90.4 % wt. dry basis) and ash content below 1 % wt. for 130–280 min and specific energy consumption ranging from 4.5 to 8.9 MWh∙m³ depending on the sample and conditions. to further decreases the ash content (below 0.5 % wt. corresponding to conductivity <2 mS∙cm) the energy requirement increases by almost three times confirming that while electrodialysis is a suitable technology for deeper waste stream purification, but energy supply and costs may hamper the implementation at scale.

中文翻译：

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在工业相关条件下通过电渗析纯化废物甘油的实验优化


对来自第二代生物柴油精炼厂的合成和预处理的不纯甘油进行纯化，以将灰分含量降低到 1% wt 以下。选择电渗析纯化是因为它能够选择性地从甘油中去除盐。首先，测试富含合成甘油的样品，以优化电池电压、膜类型和运行时间，以实现 1% wt 的目标。灰。之后，使用工业预处理的甘油作为原料流并进行比较。综合测试活动表明，回收率大于 60%，甘油纯度大于 82.2%（湿基和 90.4% 干基重量），灰分含量低于 1% 重量。持续 130–280 分钟，具体能耗范围为 4.5 至 8.9 MWh∙m3，具体取决于样品和条件。为了进一步降低灰分含量（低于 0.5 % wt.，对应于电导率 <2 mS∙cm），能量需求增加了近三倍，这证实了虽然电渗析是一种适合更深层次废物流净化的技术，但能源供应和成本可能会阻碍大规模实施。