Gibbins, Jon

Chalmers, Hannah

Trabadela Robles, Ignacio

Engineering and Physical Sciences Research Council (EPSRC)

2015-10-29T11:02:01Z

2015-10-29T11:02:01Z

2015-11-26

Carbon Capture and Storage (CCS) is a legitimate technology option that should be part of a balanced portfolio of mitigation technologies available Post-Kyoto Protocol framework after Paris 2015 and beyond the 2020s or the cost achieving 2 degrees Celsius stabilisation scenario will significantly increase. Oxy-fuel combustion as a CCS technology option increases fuel flexibility. Additionally, oxy-biomass as a bio-energy with CCS (BECCS) technology can achieve negative carbon dioxide (CO2) emissions in sustainable biomass systems. Also, oxygen (O2) production in an air separation unit (ASU) gives potential for extra operational flexibility and energy storage. In this work, new designs of 20 litre spherical (R-20) and 30 litre non-spherical (R-30) ignition chambers have been built at the University of Edinburgh to carry-out dust ignition experiments with different ignition energies for evaluating pulverised fuel ignitability as a function of primary recycle (PR) O2 content for oxy-fuel PF milling safety. A set of coals and biomasses being used (at the time of submitting this work) in the utility pulverised fuel boilers in the UK have been employed. Coal and biomass dusts were ignited in air and oxy-fuel mixtures up to 30 % v/v O2 balance mixture CO2 where peak pressures (Pmax) from ignition were recorded. Pressure ratios (Pmax/Pinitial) were determined the key parameter for positive ignition identification with a value above 2.5 to be considered positive. Particle size effects in coal and biomass ignition were evaluated. Results on biomass were more variable than with coals, requiring a stronger ignition source (5,000 J) mainly due to larger particle sizes. Finer biomass particles behaved similarly to air ignition in 25 % v/v O2 in CO2. Larger particles of biomass did not ignite at all for most cases even reaching 30 % v/v O2 in CO2. A reference coal used, El Cerrejon, behaved as expected with 30 % v/v O2 balance CO2 matching air case; particles between 75-53 microns had lower ignitability than finer below 53 microns but were critical in devolatilisation. Most fuels did not ignite in 21 % v/v in CO2 below 200 g/m3 concentrations. The use of adequate ignition energy strength is needed for the PF mill safety case, with 5,000 J energy required for the biomasses tested. An indication of potential ignition chamber volume and geometry effect has also been observed when comparing results from R-20 and R-30 ignition chambers. Important implications include that oxy-biomass PR with 21 % v/v O2 content would give improved pulverised fuel (PF) milling safety when compared to air firing but reduced ignitability and a 25 % v/v O2 balance CO2 atmosphere would approach to oxy-biomass ignition behaviour in air in mills.

http://hdl.handle.net/1842/10665

en

The University of Edinburgh

Chalmers, H., Al-Jeboori, M., Anthony, B., Balusamy, S., Black, S., Cavallo Marincola, F., Clements, A., Darabkhani, H., Dennis, J., Farrow, T., Fennell, P., Franchetti, B., Gao, L., Gibbins, J., Hochgreb, S., Hossain, M., Jurado, N., Kempf, A., Liu, H., Lu, G., Ma, L., Navarro- Martinez, L., Nimmo, W., Oakey, J., Pranzitelli, A., Scott, S., Snape, C., Sun, C.-G. , Sun, D., Szuhánszki, J., Trabadela, I., Wigley, F., Yan, Y., Pourkashanian, M., (2014), OxyCAP UK: Oxyfuel Combustion - academic Programme for the UK, Energy Procedia, Volume 63, 2014, Pages 504-510, ISSN 1876-6102, http://dx.doi.org/10.1016/j.egypro.2014.11.055.

Trabadela, I., (2012), An Overview of research activities on coal dust ignition at NIOSH, US October-December 2011, OxyCAP UK Meeting, 19th April 2012, University of Edinburgh, UK.

Trabadela, I., (2012), Impact of the OxyCAP UK project, Impact statement as part of the RAPID process, phase 1, UKCCSRC Early Career Researchers Meeting, 25th June 2012, University of Leeds, UK.

Trabadela, I., Chalmers, H. and Gibbins, J., (2012), Opportunities for improving oxy-fuel flexibility and operational conditions, 9th European Conference on Coal Research and its Applications (ECCRIA9), University of Nottingham (UK ) 10-12 September 2012.

Trabadela I., Chalmers H. and Gibbins J., (2013) Coal dust ignition experiments for oxy-fuel safety, 3rd Oxy-fuel Combustion Conference (OCC3), International Energy Agency Greenhouse Gases Programme (IEAGHG), Ponferrada/CIUDEN (Spain) 9-13 September 2013.

Trabadela, I., Chalmers, H. and Gibbins, J., (2014), Oxy-biomass Ignition in Air and Relevant Oxy-combustion Atmospheres for Safe Primary Recycle and Oxy-burner Development, Energy Procedia, Volume 63, 2014, Pages 403-414, ISSN 1876-6102, http://dx.doi.org/10.1016/j.egypro.2014.11.042.

coal

biomass

ignition

Oxy-fuel

Carbon Capture and Storage

CCS

Ignition of suspensions of coal and biomass particles in air and oxy-fuel for Carbon Capture and Storage (CCS) and climate change mitigation

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy