Novel Two-Stage Process for Manufacturing Butadiene from Ethanol

Replacing petrochemicals with products obtained from renewable raw materials is a top challenge today. The paper deals with the design and simulation of a sustainable process for manufacturing butadiene from bioethanol with a capacity of 91,000 t/year. The two-stage process employs a selective CuO/Cr2O3 catalyst for ethanol dehydrogenation and recent yield-performant Ta2O5 catalyst for butadiene synthesis. The paper develops original flowsheets suitable for industrial implementation based on comprehensive kinetic models that provide a realistic description of the actual chemistry. The development of a complex separation system makes use of a systematic task-oriented methodology. Efficient separation methods are applied according to the chemical nature and physical properties of species for removing numerous impurities generated in reactions. The overall butadiene mass yield and carbon yield are 0.495 kg butadiene/kg ethanol (vs the maximum value 0.587) and 0.837, respectively. The catalyst productivity is 0.253 kg butadiene/kg cat.h. Substantial energy savings are achieved by heat recovery around the chemical reactors and by applying heat pumping for ethanol recovery and recycling. The sustainability analysis reveals low material intensity (0.227 kg waste/kg butadiene), moderate energy intensity (0.562 kW h/kg electrical energy and 15.8 MJ/kg thermal utilities), and low impact on the environment. The economic analysis pinpoints the possibility of achieving butadiene prices competitive with petrochemical products if the process is integrated in a biorefinery.

Automated summary

This paper examines a sustainable process for manufacturing butadiene from bioethanol, which utilizes CuO/Cr2O3 and Ta2O5 catalysts for efficient synthesis, and employs systematic separation methods. The results demonstrate low material intensity and minimal environmental impact associated with the process.