A Practical and Theoretical Analysis of Dimethyl Ether Use as a Solvent for Oil Extraction

James E Kossen

This manuscript investigates the potential of dimethyl ether (DME) as a solvent in continuous oil extraction systems for canola and spent coffee grounds. Currently, commercial oilseed processing relies predominantly on mechanical pressing methods, which are less efficient for oil recovery than solvent extraction methods. Solvent extraction methods only have use for large-scale systems and are usually not commercially viable for small scale systems. Previous research on DME extractions primarily focused on laboratory-scale batch extractions and drying applications. Laboratory-scale batch analysis was performed in this work to determine key variables that would influence the continuous extraction system. The results from laboratory batch analysis demonstrate the efficiency of DME extracting oil from various substrates, under varying conditions including contact time, particle size and moisture content. This work investigates the economic viability of using DME in a continuous extraction system with techno-economic analysis and energetic comparison analysis with existing extraction methods. The techno-economic model was built using an Aspen Plus model of the system with data from the laboratory analysis. The techno-economic analysis for canola and spent coffee grounds reveals that the crush margin significantly influences the economic viability of using DME for canola extraction, while spent coffee grounds were heavily influenced by the sale price of the solid and liquid product streams. Under specific conditions, DME extraction proves to be an economically viable solution for both canola oil extraction and spent coffee grounds disposal. Comparing DME and hexane for canola extraction with regards to energy and environmental impact, the former shows lower energy requirements due to the lower heating requirements. The GGH emissions of a DME system are less favourable than hexane due to the emissions associated with electrical power which a DME system is heavily reliant on. However, DME is a non-toxic and non-flammable solvent which will potentially be a safer and more environmentally friendly option for oil extraction when considering the green origin of DME as opposed to hexane. In conclusion, this study demonstrates the potential of DME as a solvent in continuous oil extraction systems for canola and spent coffee grounds. Further research including construction of a pilot scale continuous system based on this work would be required to fully explore its potential and further explore the economic viability of the system.

A Practical and Theoretical Analysis of Dimethyl Ether Use as a Solvent for Oil Extraction

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