The approach to the commissioning of a heat-recovery steam generator in the industry has varied from project to project. One school of thought contends that no chemical cleaning (or minimal) is required. The second school of thought contends that a complete chemical cleaning is required. This report discusses these differences, and a properly designed and well executed cleaning with desired results.
A stochastic model of the overall cleaning process and consequent corrosion was developed for an ethylenediaminetetraacetic acid (EDTA) based cleaning process. The model includes: (1) a chemical reaction engineering model(s), (2) a finite-element analysis (FEA) and (3) a Markov model of non-uniform corrosion sites.
This CorrCompilation series focuses primarily on equilibrium-formed scales, where an aqueous fluid changes from an unsaturated equilibrium state to a saturated and supersaturated state and then solids may start to form. These types of fouling minerals include alkaline earth salts, silicates, alkaline salts (NaCl), sulfides, and under specific circumstances, metal sulfide salts that form through equilibrium changes. While corrosion product scales are not the subject of this book, the importance of corrosion product layers to the deposition of other scales will be described.
Since this is a CorrCompilation and more than 90 copies of NACE papers are attached, the work is published in four volumes. The editor, Wayne W. Frenier, FNACE, provides an extensive introduction to each volume, offering the reader a thorough mix of history, theory, and engineering techniques and methods for addressing scale.
Volume 1: Introduction to Equipment Subject to Inorganic Scale
Volume 2: Current Mechanisms for Understanding Inorganic Scale Formation and Deposition
Volume 3: Chemistry and Application of Scale Inhibitors
Volume 4: Alternative Methods of Scale Control
This fourth volume, "Alternative Methods of Scale Control," reviews methods for controlling inorganic scale that provide alternatives to chemical SI methods or those that may be used with SIs to enhance management for an entire connected system. The first sections (1 and 2) describe non-chemical methods such as anti-scaling surfaces and electronic methods for reducing scale deposition.