ABSTRACT

This study provides an extensive analysis of the limitations for the old generation of water and steam cycle chemistry used in boiler water treatment, using a case study of an operational gas plant running since 1977. Key failures observed included hydrogen damage (HD), high temperature stress rupture, and acid phosphate corrosion, all attributable to heavy deposits resulting from outdated boiler water chemical control program. These failures impact process production, boiler performance, and safety, prompting the need for improved treatment options. The paper recommends transitioning to modern chemical treatment methods, including the adoption of a new phosphate program, an upgrade to monitoring systems, the performance of chemical cleaning to remove heavy oxide deposits, and revision of alarm limits to accommodate the new generation of chemical treatments. By implementing these strategies, the integrity and operational efficiency of boiler units can be safeguarded, promoting the sustainable operation of aging gas plants and mitigating the risks associated with old-generation chemical programs.

INTRODUCTION

Boilers are critical components in gas plants, providing steam for a wide range of process and utility applications. However, with aging, boilers become more prone to integrity challenges, impacting process production, boiler performance, and safety. This case study examines on an operational gas plant in operation since 1977, shedding light on the complexities of managing integrity issues in aging boilers.

One prominent issue identified in this study is the accumulation of heavy deposits and under-deposit corrosion (UDC) in boiler tubes. To understand the underlying causes of these malfunctions, a comprehensive study of the boiler's steam and water chemistry, combined with failure analysis, was carried out.

The aim of this paper is to provide an in-depth review of the conventional water and steam cycle chemistry used for boiler water treatment. Specifically, we investigate the limitations of current treatments, like phosphate treatment, and their impact on boiler integrity.

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