Achieving emissions compliant performance on conventional coal and gas boilers with minimal investment and without sacrificing flexibility or efficiency; through the application of advanced combustion engineering.

摘要

The primary technology deployed to achieve NOx emissions compliance on fossil fuel fired boilers has been the installation of a staged firing system, incorporating Over Fire Air. Application of this technology has led to the development of many off-the-shelf products, which are only slightly adapted for each application. However, each boiler has unique requirements as a result of their design, age, geographic location, fuel, auxiliary plant system and their plant layout. Failure to account for these unique demands when retrofitting a low NOx firing system has, in many cases, produced adverse effects such as high CO or LOI, or limitations of boiler capacity and flexibility. Equally, where the firing system has been incapable of providing the required NOx performance, a flue gas treatment plant (SCR) has been required; which represents a huge capital investment, compounded by significant operational costs. These expenses, both performance and financial, can be avoided with the proper application of detailed engineering at the design stage. RJM International has been providing exactly that kind of solution to the power generation and process industries for many years, with over 60,000MWe of reference plant across a range of fuels and firing arrangements. Maintaining the boiler’s thermal profile through proper control of combustion can eliminate flexibility limitations which can result in high superheater temperatures of CO emissions. Similarly, the operating range of a boiler can often be expanded to allow operation at lower MSG, through new flame dynamics which accommodate stable combustion at lower turn- down. This paper explores the techniques used by our engineers to solve these challenges with innovative cost-effective solutions, centred on an analysis of 4 case studies.