Exploiting sustainable fuels for extra power
The EU has set ambitious goals to develop alternative forms of energy in order to reduce emissions while increasing the reliability and security of its power supply. Combined heat and power (CHP) uses the vast amount of wasted heat released from electricity generation from a variety of fuels, enabling overall efficiency in excess of 80 %. Until now, the implementation of small-scale, direct biomass-to-electricity CHP systems has been limited mainly due to the quality and availability of biomass and its low-energy density. Scientists initiated the EU-funded project 'Engine and turbine combustion of bioliquids for combined heat and power production' (BIOLIQUIDS-CHP) to exploit the benefits of converting solid biomass into bioliquids. In order to do so, they had to adapt engines and turbines to operate efficiently with a variety of bioliquids including pyrolysis oil. Simultaneously, they upgraded bioliquids to improve combustion properties. Investigators chose four engines as test cases. They modified an internal combustion (IC) engine to achieve pyrolysis oil-resistant engine parts. The diesel engine operated for 40 hours on pure pyrolysis oil with no change in fuel pump or injector and no significant effect on flue gas emissions. Extensive research on catalysts led to a working CHP plant using a second IC engine with a generator, exhaust gas cleaning system, heat unit and microprocessor control system. Work on the external combustion engine resulted in an exceptional new heat engine compatible with any heat source and covering a temperature range of 50 to 1 000 degrees Celsius. Modified design of the MGT combustion chamber enabled a reduction in flue gas emissions using biodiesel and vegetable oil. Scientists also successfully developed tertiary blends of pyrolysis oil, biodiesel and alcohol, for which process a patent has been submitted. In addition, the production of fast pyrolysis emulsions with biodiesel was proven effective and subsequently up-scaled. BIOLIQUIDS-CHP results should have far-reaching impact on fuels, engine components and engines. Overall, project outcomes are expected to enhance the market penetration of CHP units and thus help the EU to achieve its targeted CHP energy goals.
