Treatment project seeks boost for bioenergy

THE UK’s Energy Technologies Institute (ETI) has launched a new £2.2m (US$2.74m) project to improve processes used to pre-treat biomass feedstocks.

The project seeks to demonstrate that removing impurities and contaminated material from the likes of forestry waste and Miscanthus grass would bring downstream operational benefits to the bioenergy sector. Reducing the costs would help plants that burn biomass compete against those that burn fossil fuels, reducing net greenhouse gas emissions.

The project is being led by biomass specialists Forest Fuels working with Uniper Technologies. A prototype biomass pre-treatment plant will be built at Forest Fuel’s depot in Nottinghamshire.

The project programme manager Geraint Evans, who is a Fellow of IChemE, told The Chemical Engineer that the project will seek to remove stones, soil and other materials such as leaves picked up during harvesting.

“The main impact of washing will be to remove surface contaminants, but the degree of leaching will be an important investigation in this project. Ideally, for biomass, removing alkali metal salts would be high on the agenda for example. The first part of the project will look at upgrading waste woods to make them cheaper to use – i.e. to remove enough contaminants to allow the end user to run their boilers more efficiently, at high steam temperatures for example, and for longer between maintenance points.”

He added that the project will test water washing of biomass as this cheap option will avoid adding significant cost to the supply chain.

“Other supporting processes including chipping and of course handling and drying processes will be incorporated into the process scheme. We will be analysing energy use and greenhouse gas emissions in the process as part of our project along with the economics as ETI is keen to see this technology, if successful, commercialised.”

The treated feedstocks will be blended and combustion tested at the University of Sheffield’s pilot scale advanced capture technology facilities, with support from the university’s Energy 2050 Institute.

Evans said: “We want to show that improving the quality of biomass feedstocks … is a viable way of increasing the amount of sustainable sources of bioenergy, obtaining more energy from them and delivering improved greenhouse gas savings.”

“The intention is that once the process has been proven and tested it could then be used on other bioenergy crops and scaled up to treat larger amounts of material creating even greater efficiencies.”