Abstract Sodium pyruvate is an important intermediate chemical in the fine chemical, food and pharmaceutical industries. Efficient treatment for waste centrifugal mother liquid (mainly containing ethanol, water and residual sodium pyruvate) generated during the production of sodium pyruvate is highly important to improve the process economy. A pervaporation-crystallization (PC) process is presented in this study for simultaneous recovery of ethanol and sodium pyruvate products from waste centrifugal mother liquid. The PC process contains two-step operation, i.e., the first step is low-temperature pervaporation for water removal, and the second step is cooling crystallization followed by filtration to collect ethanol and crude sodium pyruvate. Mass-produced NaA zeolite membranes show remarkable pervaporation performance for separating ethanol/water/sodium pyruvate mixtures with the water/ethanol separation factor always over 10,000 under various operational conditions. The potential deposition of sodium pyruvate on the outer membrane surface during the long-term use would decrease the total flux. However, the pervaporation performance of NaA zeolite membrane could be easily recovered by water washing regeneration. A pilot-scale study on the PC process for treatment of actual waste centrifugal mother liquid is successfully performed, suggesting the good technical feasibility of PC process for industrial application.

中文翻译：

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从废离心母液中同时回收乙醇和丙酮酸钠的渗透蒸发结晶（PC）工艺

摘要 丙酮酸钠是精细化工、食品和医药工业中重要的中间体化学品。对丙酮酸钠生产过程中产生的废离心母液（主要含有乙醇、水和残留丙酮酸钠）进行有效处理，对提高工艺经济性具有重要意义。本研究提出了一种渗透蒸发结晶 (PC) 工艺，用于从废离心母液中同时回收乙醇和丙酮酸钠产品。PC工艺分两步操作，即第一步低温渗透蒸发除水，第二步冷却结晶，过滤收集乙醇和粗丙酮酸钠。大量生产的 NaA 沸石膜在分离乙醇/水/丙酮酸钠混合物方面表现出显着的渗透蒸发性能，在各种操作条件下，水/乙醇的分离系数始终超过 10,000。长期使用过程中丙酮酸钠在外膜表面的潜在沉积会降低总通量。然而，NaA沸石膜的渗透蒸发性能可以通过水洗再生轻松恢复。PC工艺处理实际废弃离心母液的中试研究成功，表明PC工艺具有良好的工业应用技术可行性。长期使用过程中丙酮酸钠在外膜表面的潜在沉积会降低总通量。然而，NaA沸石膜的渗透蒸发性能可以通过水洗再生轻松恢复。PC工艺处理实际废弃离心母液的中试研究成功，表明PC工艺具有良好的工业应用技术可行性。长期使用过程中丙酮酸钠在外膜表面的潜在沉积会降低总通量。然而，NaA沸石膜的渗透蒸发性能可以很容易地通过水洗再生来恢复。PC工艺处理实际废弃离心母液的中试研究成功，表明PC工艺具有良好的工业应用技术可行性。