Techno-Economic Analysis of a Glycerol Biorefinery

Artikel i vetenskaplig tidskrift, 2018

Biodiesel is an environmentally friendly alternative to fossil fuels, which is experiencing a steep growth in market size. Because the most common biodiesel production technology is based on the transesterification of triglycerides, a burgeoning amount of glycerol byproduct is obtained. In order to address this economic and ecologic drawback, several chemocatalytic technologies have been developed to exploit this compound to feed the market with added-value products. Lactic acid, acrylic acid, allyl alcohol, propanediols, and glycerol carbonate have emerged as the most relevant candidates for this purpose. In previous studies, an environmental and economic assessment of a glycerol biorefinery built on these valorization pathways has been performed, taking into account only the operating costs in relation to the economic aspects. This study evaluates for the first time the investment required by these glycerol valorization processes, based on the Guthrie, Taylor, and Aspen capital cost estimation methods, and then assesses the potential of a heat-integrated glycerol biorefinery. Glycerol carbonate stands out as the dominant product to maximize the profitability with respect to the glycerol utilized, while 1,2-propanediol and allyl alcohol are determined as target compounds to be included in the glycerol biorefinery product mix if further reductions of the environmental impact are sought after. This early stage techno-economic analysis provides a sounder basis toward the practical realization of an integrated facility sustainably upgrading waste streams from the processing of renewables into commodities, thus promoting the concept of circular economy.