Are Outputs from a Coffee Waste to Biofuel Process Effected by Bean Type?

Waste coffee grinds are a potential feedstock for the production of biofuel, according to new research from Bath University’s Centre for Sustainable Chemical Technologies, but does the type of bean have an effect on quality or quantity? According to the researchers, oil can be extracted from coffee grounds by soaking them in an organic solvent, before being chemically transformed into biodiesel via a process called ‘transesterification’. The study, Effect of the Type of Bean, Processing, and Geographical Location on the Biodiesel Produced from Waste Coffee Grounds, looked at how the fuel properties varied depending on the type of coffee used. As part of the study, the researchers from Bath University made biofuel from ground coffee produced in 20 different geographic regions, including caffeinated and decaffeinated forms, as well as Robusta and Arabica varieties. “Around 8 million tonnes of coffee are produced globally each year and ground waste coffee contains up to 20 per cent oil per unit weight,” explained Dr Chris Chuck, Whorrod Research Fellow the university’s Department of Chemical Engineering. “This oil also has similar properties to current feedstocks used to make biofuels. But, while those are cultivated specifically to produce fuel, spent coffee grounds are waste. Using these, there’s a real potential to produce a truly sustainable second-generation biofuel,” he added. The researchers suggested that while biofuel from coffee would be a relatively minor part of the energy mix, it could be produced on a small scale by coffee shop chains to fuel vehicles used for deliveries. These same delivery vehicles could be used to collect spent coffee grinds and take them to a central biodiesel production facility to be processed. The university also noted that companies such as London-based bio-bean already produce biodiesel and biomass pellets from waste coffee grounds. Rhodri Jenkins, a PhD student in Sustainable Chemical Technologies and first author of the study, said: “We estimate that a small coffee shop would produce around 10kg of coffee waste per day, which could be used to produce around 2 litres of biofuel.” “There is also a large amount of waste produced by the coffee bean roasting industry, with defective beans being thrown away.” He continued. “If scaled up, we think coffee biodiesel has great potential as a sustainable fuel source.” However, according to Chuck, the yields and properties of biodiesel can differ depending on the growth conditions of current biodiesel feedstocks, sometimes causing them to fall out of specification. The research found that there was a reasonably standard composition and little variation in the relevant physical properties of the fuels, irrespective of the source. This means that all waste coffee grounds are a viable feedstock for producing biodiesel. “The uniformity across the board for the coffee biodiesel fuel is good news for biofuel producers and users,” Chuck concluded. The researchers said that they are also looking at using other types of food waste as a feedstock to make biofuels and expect to publish their findings later in this year. An ‘Elevator Pitch’ from Bio-Bean can be watched in the video below. Read More Pyrolysis Oil from Norwegian Wood Waste Investigated as Marine Biofuel Scientists are working to produce biofuel suitable for marine diesel engines by ... is funded by Norwegian industry partners and the Research Council of Norway. VIDEO: Biorefinery Turns Starbucks Waste in Sustainable Products in Hong Kong A new 'biorefinery' intended to transform biowaste into key building blocks for the manufacture of renewable plastics, laundry detergents and scores of other everyday products has been successfully tested using waste from Starbucks in Hong Kong. Biofuel from Wastes a Huge Missed Opportunity for Europe Europe is missing a significant opportunity to convert household wastes, as well as industrial, agricultural and forestry wastes, into advanced biofuels.