Institute for Sustainability

Integrated Process for Conversion of CO2

Integrated Process for Conversion of CO2 into Value-added Product, and Simultaneous Production of Biodiesel without Waste Glycerol by-product

Summary

An integrated sustainable process that combines conversion of CO2 into dimethyl carbonate, (DMC) with simultaneous transesterification of triglycerides (TG) to produce biodiesel and glycerol carbonate (GLC) is being investigated. The project is designed to reduce global CO2 emissions by catalytically converting it into a valuable product dimethyl carbonate (DMC), while simultaneously eliminating the excess of waste crude glycerol associated with conventional biodiesel processes. More than 32 billion tonne/year of CO2 emission occurs worldwide from fossil fuels combustion only, whereas over 2 million tonnes of waste crude glycerol is produced annually from conventional biodiesel processes.

This new process will be a very important and timely contribution to current real-world sustainability issues, as the process will utilise two substantial industrial waste streams, CO2 and crude glycerol. A huge market exists for glycerol carbonate, as its worldwide production was estimated to rise from the current value of less than 100,000 tonne/annum to EuroBioRef target market volume of 30 million tonnes per annum. Integration of conventional biodiesel processes globally would create wealth and lead to substantial reduction in CO2 emission. The EU biodiesel output stands at approximately 24 million tonne/year, corresponding to co-productions of 2.4 million tonne/year of waste crude glycerol. Therefore, about 3.1 million tonne/year of glycerol carbonate can be produced on replacement of the conventional biodiesel processes in Europe with the proposed integrated biodiesel process.

Project Aims:

  • The catalytic system for the integrated process will be designed using an acid-base bifunctional catalyst to allow the process units for DMC production and triglyceride transesterification to be combined either sequentially (Figure 1) or into a single process. 
  • It is expected to improve the efficiency of valorisation of CO2, and triglyceride transesterification at moderate reaction conditions, without the use of expensive CH3I as a catalyst promoter/reagent for the DMC production step. 
  • The integrated process will be implemented in oscillatory packed bed reactors.
Integrated Process for Conversion of CO2 project
Figure 1: Process units - conversions of CO2 into DMC coupled with triglyceride transesterification.