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Minimizing HRSG Costs and Limitations for Small Scale Power Generation Using Vertical Once Through Boiler Technology

John Cockerill, Webcast Experts, OTB



Increasing trends in highly flexible power generation and the need for energy in proximity to end users is expanding the role of small scale power plants for distributed generation (DG), cogeneration and combined heat and power (CHP) technologies. The ideal fit for these fast, flexible technologies is typically in the capacity range of less than 1 kW to 100 MW. Equipment can be packaged as modular systems which require only a small footprint with minimal field erection.

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Small scale combined cycle gas turbine (CCGT) technology, with or without integration of renewables, is well-suited for producing decentralized DG power. However, there are some limitations with CCGT plants for small scale power generation (<100 MW) when they incorporate traditional horizontal or vertical HRSG drum boilers. Drum boilers require periodic blowdown for removal of suspended solids and bottom sludge and this requires the use of chemicals such as hydrazine or phosphates in addition to replenishment of make-up water. Distinct economizer, evaporator and superheater zones within a HRSG drum boiler require associated piping, instruments and controls. In addition, the high-pressure drum limits temperature increases upon startup resulting in long start-up times.

John Cockerill Energy, formerly known as Cockerill Maintenance & Ingénierie (CMI), has introduced its Once Through Boiler (OTB) which eliminates several of the drawbacks associated with drum type HRSGs. Unlike the traditional HRSG boiler design where economizer, evaporator and superheater sections are interconnected with a high-pressure steam drum, in the OTB design water is heated, vaporized, and superheated in a single serpentine tube. With the OTB design, boiler efficiency is improved as there is no approach temperature associated with a high-pressure drum and flexibility increased with the inclusion of fast start and dry run capability. As delivered and installed, the OTB provides the smallest footprint and lightest weight making the OTB ideal for simple cycle conversions to combined cycle as well as floating power plants. Other key features include a simplified boiler design with maximum flexibility, controlled GT emissions in open cycle and fast steam cycle startup and shutdown capability.

During this informative webinar, Pascal Fontaine and Caleb Lawrence of John Cockerill, will discuss key features, applications, and benefits of the OTB design. Specific topics to be addressed will include:

  • How OTB provides for flexible operations, fast steam cycle start-up and shutdown

  • How OTB provides stability of operation at low gas turbine load while maintaining steam temperature 

  • How OTB simplicity of design provides lowest life cycle cost

  • How OTB can control GT emissions in open cycle 

In addition, case studies for existing GT projects will be discussed.

Who should attend:

  • Power Project Developers

  • Utilities, Power Plants & CHP 

  • Gas Turbine OEMs

  • EPCs

  • Flexible CCGT units

  • FLNG Plants

  • Decentralization & Renewables Integrators

Attendees can ask additional questions which will be covered during the Q&A session at the end of the webinar.


Pascal Fontaine, John Cockerill

Pascal Fontaine | VP Marketing & License Manager | John Cockerill

Pascal Fontaine, John Cockerill VP Marketing & License Manager, graduated as a professional Engineer in Power Generation from the University of Liège in Belgium. He gained his experience on HRSG design and project management working for CMI Energy for over 17 years in Process Engineering, Technical Project Management, Proposal Management and Tendering Management. He is the author of several papers and international publications on both Horizontal and Vertical HRSG technologies and cycling solutions for increased flexibility on combined cycle power plants.

Robert Dautovich, John Cockerill

Robert Dautovich | OTB Director | John Cockerill

Robert Dautovich, John Cockerill OTB Director, is a Professional Engineer and graduated from the University of Waterloo in Canada. He gained experience with many boiler technologies throughout his career and spent the last 25 years leading the development and commercialization of Once Through Boiler Technology for combined cycle and cogeneration facilities for the worldwide market.

Caleb Lawrence, John Cockerill

Caleb Lawrence | OTB Sales Manager | John Cockerill

Caleb Lawrence, John Cockerill OTB Sales Manager, is a Professional Engineer and a graduate in Mechanical Engineering from the University of Victoria in Canada.  Caleb has worked the boiler industry for 19 years in Design and Proposal Engineering, Sales and Marketing Management, Fleet Management and senior sales leadership roles.  He has gained extensive experience in international Sales and Business Development.