ABSTRACT

 An increasingly stringent and uncertain regulatory environment and lower natural gas prices have made converting existing steam generating boilers to natural gas firing increasingly attractive.

This paper provides a general feasibility assessment of projects that have converted coal-fired steam generating units to 100% natural gas firing. We present an approach to assess permitting impacts to the project that dictate the direction and scope in terms of required equipment to achieve the targeted emissions. The project’s technical feasibility, including burner technologies for a range of different boiler firing configurations, natural gas effects on thermal performance, American Society of Mechanical Engineers (ASME) and National Fire Protection Association (NFPA) code requirements, and air pollution control equipment are discussed.

A case study is presented that involved the conversion of existing industrial boilers. The implementation of the project is discussed, including the design of the natural gas piping/delivery system on the plant premises, new gas-fired burners, heat absorption impacts with existing heat transfer surfaces, and impact on the balance-of-plant equipment and design. The project was successfully completed in November 2014.

Authors:
Marc E. Lemmons, Bryan J. McGowan - Sargent & Lundy
Bryan M. Lewis - Domtar Paper