Insights and Commentaries

Safety in oxyfuel combustion: a case study from Australias Callide Oxyfuel Project

16th January 2016

Topic(s): Carbon capture, Engineering and project delivery, Health, safety and environment, use and storage (CCUS)

The Callide Oxyfuel Project in central Queensland, Australia ran in demonstration phase from June 2012 to March 2015. The project has produced valuable data on oxyfuel combustion processes and technology for retrofitting to coal-fired power stations. In this final instalment in a series of three Insights, Project Director, Chris Spero, discusses the health and safety challenges of oxyfuel technology. Further detailed information about the safety and hazard aspects of the Callide Oxyfuel project is available in Part Four of the report 'Callide Oxyfuel Project - Lessons Learned' available on the Global CCS Institute site.

Introducing the elements of oxyfuel combustion and carbon capture presents additional health and safety challenges and risks to traditional coal fired power plants

Callide Oxyfuel Project Director, Chris Spero, addressed industry experts at the IEA GHG Oxy-Combustion Research Network in China in October this year, speaking on the hazards and safety aspects of introducing the new elements of oxyfuel combustion and carbon dioxide (CO₂) capture to existing coal fired power plants.

In his address, Dr Spero drew on the experience he gained during the twelve years he was involved in the feasibility, design, planning, building, and operating the world’s first oxyfuel CCS retrofit project.

“We were able to deliver the Callide Oxyfuel Project with an exemplary safety performance, despite the application of first-of-a-kind technology and elevated hazard potentials – both physical and chemical.”

According to Dr Spero, the project was underpinned by a rigorous process of hazard identification and control, from design right through to operations.

“We really thought about the integration of control measures early in the process to ensure the project was implemented from the outset with good design, good systems and thorough training.”

“Of course, safety is part of a wider set of project objectives including cost and functionality, but we were able to balance competing priorities in a way that didn’t compromise safety - we considered health and safety before anything else.”

Dr Spero said the key safety studies that were undertaken during the design phase included:

• Hazard and Operability (HAZOP) Studies on Air Separation Units (ASU), Oxyfuel Boiler (OB), the CO₂ Capture Plant (CPU), and the combined system
• Boiler Safety Integrity Level (SIL Studies) for programmable safety systems on the boiler and air separation units, although this was not required for the CPU which utilised a hard-wired system
• NFPA 85 Compliance study was undertaken to assess boiler hardware and logic against the requirements of NFPA 85 - Boiler and Combustion Systems Hazard Code
• A micro assessment of the risk and control of unintended releases of hazardous substances from the ASU, OB and CPU plant was conducted
• Joint sign-off on Elements Important to Safety check sheets on the Original Equipment Manufacturer Guidelines

When addressing the Hazardous Area Zoning, Dr Spero said the Project Partners put the following control measures in place:

• Operators conducted plant walk-downs every shift
• Two large ventilation fans and fixed CO₂ detectors were installed in the CPU compressor house
• It was mandatory that personal CO₂ monitors were worn in the following areas:
  • around the boiler when it was operating in oxy-firing mode
  • around the ASU plant
  • Personal CO₂ and nitrogen dioxide (NO2) monitors were worn around CPU plant area
• Higher risk areas were delineated with barrier tape, rails and signs as necessary
• Thorough training of personnel in the hazards associated with oxy-fuel and CO₂ capture plants and how to respond
• All test work was performed under a Minor Works Permit and Job Safety Analysis (JSA); and all maintenance work was performed under a Work Permit with isolations and JSA.

These experiences at Callide proved that protocols and procedures for dealing with hazardous areas have been effective. As presented by Dr Spero; “The overwhelming conclusion is that oxyfuel combustion and CO₂ capture (utilising cryogenic distillation) can be done safely, and can be effectively managed using the tools already well established in the industry.”

The Callide Oxyfuel Project is an international joint venture between CS Energy; Australian Coal Association Low Emissions Technologies Ltd; Glencore; Schlumberger Carbon Services; and Japanese participants, JPower, Mitsui & Co. Ltd and IHI. The project was awarded $63 million from the Australian Government under the Low Emissions Technology Demonstration Fund, as well as receiving financial support from the Japanese and Queensland governments, and technical support from JCOAL. For more information see www.callideoxyfuel.com.

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