The main objective of the EU RFCS project BiOxySorb is an experimental and techno-economic assessment of 1st and 2nd generation biomass co-combustion under both air- and oxy-fuel conditions at various co-combustion ratios in combination with flexible, low cost SOx, HCl and Hg emission control by sorbent injection. The project is administered and technically coordinated by IFK.
Operators of coal-fired plants are under pressure to reduce their carbon-intensity. Available options include co-firing CO2-neutral biomass, oxy-fuel-combustion as part of a carbon capture process or, in the extreme a combination of both approaches to give a ‘CO2-negative’ power plant. These options provide an opportunity to ensure the low carbon future of coal power while also providing a flexible form of generation to supplement the increasing quantities of power from intermittent sources such as wind. These options do however extend coal-fired power plant into new operational regimes, which require significant study if they are to be optimized and the cost of these major changes minimized. Areas addressed in this project include biomass co-firing, emissions production and efficient control options (including sorbent injection), implications for flue gas cleaning equipment and ash behaviour and implications on plant operation and associated cost. To sum up, the BiOxySorb project aims to enhance the efficiency and environmental performance of coal fired power stations, to validate relevant technologies in large scale and to investigate the potential of the oxy-fuel combustion technology for co-combustion of biomass which is a CO2 capture technique with a negative carbon balance that can be applied to newly built, but also retrofitted to existing power plants. Accordingly, the following main objectives will be addressed in the project:
- Choice (based on: availability, fuel qualities, co-grinding and fuel handling) and characterization of first and second generation (e.g.: torrefied biomasses)
- Evaluation of co-combustion shares based on theoretical considerations and experimental results to realize an optimal operation under air and oxy-fuel firing conditions. Investigation of the potential of smart blending of coal and biomass for emission reduction
- Investigation of the emission behaviour (PM, HCl, CO, NOx, SOx and Hg) of various first and second generation biomasses and co-combustion shares under air and oxy-fuel conditions
- Evaluation of benefits of oxygen-enriched-air co-combustion of biomass
- Choice and evaluation of sorbents (e.g. alkalines, earth-alkalines, and activated carbon or lignite/coal coke) and investigation of their application for control of HCl, SO2, SO3 and Hg emissions under air and oxy-fuel firing conditions. The impact of sorbents on burnout and other emissions such as PM, NOx and CO will also be investigated and assessed. Moreover, the interaction of sorbent injection with different particle removal systems (ESP and bag house filter) will be evaluated.
- Evaluation of the transient behaviour of SOx and Hg reduction by sorbent injection, when changing injection parameters.
- Investigation of necessary plant modifications for high thermal share biomass co-milling and co-combustion and for injection of sorbents.
- Techno-economical study of different degrees of biomass co-combustion and emission control by sorbent injection under air and oxy-fuel conditions. Utility and technology and supplies manufacturer (E.ON, LHOIST, GBS) will use the data generated in the experimental small, technical and large scale tests to assess the impact of the co-combustion and sorbents on full-cycle, full-scale power plants and to determine their impact on cycle optimization, ash valorisation and emissions control.
- Evaluation of the impact of measured SO2, SO3 and HCl concentrations on both high temperature and low temperature corrosion in a variety of investigated configurations.
- Development of generic guidelines covering important considerations to be made in an overall economic optimisation of co-fired coal/biomass systems and the application of sorbents for emission control both with and without oxy-fuel combustion.
- Exploitation and dissemination of results (e.g.: publications; workshop in the final project year)