Plume Visibility Emission Management in a Large Size Heavy Fuel Oil Fired Diesel Engine Power Station in Macau

摘要

At the CIMAC Congress of 2004 in Kyoto a paper was submitted describing technical and design aspects of the then world's largest retrofit of a Selective Catalytic Reduction (SCR) system on stationary Diesel Engines of the Macau Electric Company (CEM) power plant located in the territory of Macau SAR (China). The SCR installation and other engine modifications implemented at the time were designed and intended to significantly improve on historically poor past environmental performance of the power plant and to take it to levels consistent with internationally accepted practice. The power plant was installed between 1987-1996 and consists of 6-off two stroke low speed engine sets of MAN-B&W design, built by Mitsui Engineering & Shipbuilding Co. Ltd (MES), and ranging in capacity from 24 to 52 MW per Unit. The SCR system installation was contracted out to a consortium of companies in November 2002, and after its complete erection was sequentially commissioned and placed into commercial service on a Unit by Unit basis during the period December 2003-May 2004. Since then, several thousand hours of SCR operating experience have been recorded, and the paper presents the serious adverse environmental problems faced in the early stages of the operation of the SCR system as installed, caused by unexpected and unacceptable plume visibility impacts onto the surrounding areas of the plant. With the involvement of the original suppliers different types of catalyst and innovative and untested plume abatement equipment options with the potential to reduce or eliminate the visibility impact were investigated and pilot tested in one of the Units at site, and summary data showing their relative technical and cost effectiveness merits are broadly discussed and presented at the Congress. The paper also provides data demonstrating several thousand hours of good plume visibility records and acceptable SCR emission results at the plant since the effective implementation in late 2005 of an operational strategy centered on a combination of fuel oil quality, engine performance tuning and a catalyst replacement process. When compared to expensive and untested options consisting of equipment add-ons involving the retrofitting of back end abatement plant, this SCR management strategy have in CEM's experience shown to be the most cost effective approach to ensure that future environmental performance of the station, both in terms of flue gas emissions and plume visual impacts, would meet internationally acceptable standards and would address local community expectations, on an economically sustainable basis. The paper highlights the experience of CEM in face of a very serious environmental impact problem faced in 2004, and discusses the range of equipment and operating management options available to large scale 2 stoke low speed Diesel Engine plant owners facing similar requirements.