Fundamental study of biofuel combustion: flame stabilisation and emissions using advanced optical diagnostics

World-wide, energy conversion is currently dominated by the combustion of fossil fuels. Electricity generation and transport are key energy consumers and contribute significantly to atmospheric CO2, NOx, and particulate emission. There is an increasing awareness in the public eye of the potential impact of particulates on health. This includes a higher risk of cancer, asthma and a potential contribution to neurodegenerative disorders (e.g., Alzheimer's disease). In the UK, particulate matter (PM) from combustion processes is a significant contributor to poor air quality in urban areas; it has been reported that more than 25,000 deaths per year could be attributed to long-term exposure to anthropogenic particulate air pollution. As reported by DEFRA, poor air quality is the largest environmental risk to public health in the UK, contributing to an estimated £2.7 billion per year in lost productivity. Air pollution also results in damage to the natural environment, contributing to the acidification of soil and watercourses. An obvious solution might be to move towards the replacement of vehicles with electric, however, this technology is limited by range, recharge times and the cost of the battery - for which there is currently not the sufficient global infrastructure to directly replace vehicles powered by internal combustion engine powered. Another complementary solution is to find alternative fuels that are tailored to reduce destructive emissions such as NOx and particulates. This has the advantage that it could be rapidly deployed due to the overlap with existing fuel station infrastructure.

The main aim of the proposed research is to provide a fundamental understanding of the combustion performance and emissions characteristics of key biofuels. This is vital knowledge to aid the development of next-generation low carbon technologies. The key objectives are: (1) to provide high-quality experimental data from a study of spray flame behaviour and emissions using advanced optical diagnostic techniques such as laser-induced breakdown spectroscopy and laser-induced fluorescence, (2) to develop new combustion chemical kinetic models, based on COSILAB (Combustion Simulation Laboratory software), predicting soot and NOx emissions and (3) to establish collaborations with industrial and academic partners to investigate power generation and transport applications for next-generation biofuels.

In the proposed research, the targeted biofuels are: (1) ethanol, (2) iso-pentanol, (3) dimethyl ether (DME) and (4) combined fuels - ethanol, iso-pentanol, DME and biomethane. These key fuels are potentially next-generation biofuels. The production paths of these fuels are either well established or achievable. Ethanol and DME have already shown evidence of reduced emissions from engine tests. The understanding of combustion chemistry is essential to enable the delivery of a low NOx and soot emission combustion system. How the local chemistry is influenced by various turbulent flow conditions will be examined in detail.

The ultimate goal of the proposed research is to improve the air quality, reducing combustion-induced emission pollution, enhancing public health and help maintain a resilient nation. The research will accelerate the development of alternative fuels for power generation and transport to meet with increased energy demand globally.

Dissemination to society will be through a range of activities to reach a variety of stakeholders. The workshops will be held at Loughborough University in September 2020 and 2021 inviting guest speakers from policy authorities, industrial technology-development manager and academic representors across biofuel refinery, biofuel combustion and low-carbon combustion technologies and engine development. The workshops are open to public to increase the awareness of the importance of clean combustion technologies and fuel sustainability. Annual outreach to the local community will be conducted through the Loughborough Community Day to increase the awareness of the importance of clean combustion technologies and fuel sustainability. A website will also be set up containing current research activities.

The biofuel combustion and emission characteristics are essential knowledge for developing the next-generation low-emission biofuel combustion engines and power generators. The research will be shared with industrial partners, for example, Perkins Engines, to discuss the potential application of biofuel combustion in gas and diesel engines. The proposed research will also initiate the development on the cost-effective modelling methods, especially targeting at the biofuel combustion and emission characteristics, aiding the industrial model development and reducing the time taken to deliver the next-generation sustainable and energy-efficient products.