Reporting from the OxyCAP Workshop, London, June 2014

Written by Katarzyna Stechly, University of Leeds, who was funded to attend the OxyCAP Workshop under the ECR Meeting Fund

The OxyCAP-UK: Oxyfuel Academic Programme for the UK Workshop was held on the 17th and 18th June 2014 at Imperial College of London, UK. The meeting was aimed to bring together academic researchers to discuss the key findings and next steps for UK and global oxy-fuel combustion Research and Development.

The event was well attended with a good mixture from academia and industry. The organisations in attendance were University of Leeds, Cranfield University, University of Kent, Cambridge University, Universität Duisburg-Essen, University of Nottingham, University of Edinburgh, Imperial College London, Alstom, Oak Ridge National Laboratory, Doosan Babcock, Drax Power Limited, Hunosa, University of Zaragosa, CSIC-ICB, IFK, University of Stuttgart, IEA, University of Waterloo, Babcock & Wilcox Co., Corrosion Menagement Ltd., IEA Clean Coal Centre.

The workshop allowed academics and industrialists to discuss and critically assess realistic progress of oxy-fuel combustion and define the future goals.

This workshop was partially supported by the UK CCS Research Centre.

The OxyCAP Workshop started with the introduction of the OxyCAP Director – Mohamed Pourkashanian. An overview of the Oxy-CAP project, progress and the future plans were presented.

The morning session of the OxyCAP Workshop: Development of UK Research Pilot Test Facilities as Validation Tools for Combustion and Emissions Modelling began with a presentation about the development of UKCCSRC PACT facilities within the OxyCAP programme and was given by Janos Szuhanszki from the University of Leeds. The OxyCAP project has developed a 250 kW Combustion Test Facility (CTF), which is part of the UK CCS Research Centre PACT (Pilot-scale Advanced Capture Technology) facilities. Janos presented methodology of the experimental programme and presented measurements that have been taken.

Next presentation was given by Nelia Jurado – PhD Research Student from Cranfield University about experiences in a 100kWth Retrofitted Oxy-combustor with Wet and Dry Recycle which is also part of the UKCCSRC PACT facilities. The main activities were experimental trials in a 100kW retrofitted oxy-combustor, and development of a kinetic model using Aspen Plus that predicts gas composition and temperatures of the process when varying the main operational parameters.

In the next session: Development of 2-D and 3-D Flame Imaging Systems for Monitoring, Analysis and Diagnostics in Oxyfuel Combustion Applications the first presentation was given by Gang Lu from the University of Kent. The experimental work using 2-D and 3-D flame imaging systems for monitoring and characterisation of oxyfuel flames was discussed. Measurements were taken on the 250 kW PACT Combustion Test Facility and to assess the performance and operability of the systems.

The second presentation in this session was given by Simone Hochgreb from the University of Cambridge. Within the OxyCAP project, a novel instrumentation system for measuring velocity, concentration and particle size distribution of pulverised coal flow has been developed. The optical diagnostics in O2-CO₂-N₂-coal flames results from the experimental programme was presented.

The afternoon session: Development of Advanced Simulation Based on CFD Modelling for Oxyfuel Applications begun with presentation CFD modelling of air- and oxy-fuel technology for pilot and full-scale applications given by Sandy Black form the University of Leeds. The work on CFD (computational fluid dynamics) modelling using RANS and LES, numerical results and its validation with experimental measurements in the 250 kW PACT coal combustion test facility were showed.

Andreas Kempf gave a presentation about LES modelling of pulverized coal air and oxycombustion with the usage of the in-house code PsiPhi. Several pilot-scale combustors have been simulated showing reasonable predictions. The future plans with employment of new submodels and deployment of LES to large-scale boilers has been presented.

The last session about Fuel Characterisation of Biomass and Coal for Oxyfuel Combustion Applications started with presentation: Drop Tube Furnace (DTF) Etudies to Understand the Impact of CO₂ and Steam on Devolatilisation and Char Burn-out for Coal and Biomass given by Colin Snape from the University of Nottingham. The experimental programme with the drop tube furnace (DTF) included investigation the impact of CO₂ and steam on devolatilisation and char burn-out in relation to normal air firing. Presented results showed the enhanced volatile matter yields and char burn-out rates that can be achieved in CO₂.

The following presentation in this session was given by Ignacio Trabadela from the University of Edinburgh. Within the OxyCAP programme, the dust ignition tests in oxyfuel atmospheres were carried out. Fundamental data on ignition under oxyfuel conditions has been gathered for a range of coal and biomass types leading to improved understanding of acceptable O₂ levels in the flue gas recycle. Insights from this work are expected to improve mill safety in oxyfuel conditions as well as providing fundamental data for combustion modellers.

The second day of the OxyCAP Workshop begun with session: Ash Transformation and Deposition in Oxyfuel Combustion Systems. John Oakey presented experimental programme on ash deposition carried out on a 100kWth Oxy-combustor at Cranfield University. A range of oxy-fuel combustion conditions have been investigated to support a series of laboratory corrosion and trace element speciation tests, which have generated new data required for the development of predictive corrosion rate and trace element distribution models.

Insights from Microstructure Analysis of Ashes was the last presentation in this OxyCAP Workshop. Ash transformation and deposition in oxyfuel environments has been explored in a programme of work led by Imperial College London, which has characterised samples generated by pilot scale tests undertaken by other OxyCAP partners. The work carried out in OxyCAP leads to creation of database that provides important information that is relevant to improved understanding of re-circulating flue gas, containing ash particles with size distribution and abundance that is combustor-specific, on the concentration and distribution of minor and trace elements in the combustor.