Producing glyceric acid from glycerol via integrating vacuum dividing wall columns: conceptual process design and techno-economic-environmental analysis

Abstract

Production of glyceric acid (GLA) by the oxidation of glycerol is a promising green and efficient process, which could replace conventional biological fermentation with low efficiency. However, simultaneously achieving the efficient oxidation of glycerol to GLA and the separation of subsequent products remains a challenging task due to the easy decomposition and condensation of selective oxidation products at high temperature. Herein, we propose a novel glycerol to GLA process (termed as VDG process) by bringing insight into the essence of thermal-sensitivity. In the VDG process, glycerol is selectively oxidized to GLA and other thermal-sensitivity byproducts by our recently developed PtRu/MCM-41 nanocatalysts under base-free conditions. The high purity separation of products is realized at a temperature lower than its decomposition temperature through integrating the vacuum dividing wall columns. This intensified process reduces the energy consumption and production cost. Compared with the conventional glycerol to GLA process, this VDG process provided up to 61.3% increase in energy efficiency and 47.9% reduction of the total production costs. Moreover, the life cycle assessment from multi-scales obviously indicates that the performance of greenhouse gas emissions, non-renewable energy demand and waste water generation in the VDG process are about 5.0 times, 1.6 times and 9.5 times lower than the conventional process, respectively. The results in this study harbour tremendous guiding significance to the design of efficient biomass polyol conversion to value-added products.