Practical Evaluation of Treatment Chemicals For Scale Inhibition In Open Evaporative Seawater Cooling Systems

摘要

In certain parts of the world, the use of seawater as make up water for specially designed open evaporative cooling water systems is becoming increasing popular. This poses the same potential for corrosion, scaling, deposition and microbiological fouling as with most other fresh water make up sources used in cooling systems, but in the case of seawater, or brackish water, the potential and severity is much greater.Corrosion is typically designed out by using corrosion resistant materials. Microbiology is typically controlled by chlorination since it is the most cost-effective. Scaling and deposition remain a main concern, which lead to basic evaluation of deposit control agent performance in concentrated seawater in 2000. Since these studies, advances and enhancements have been made in this domain, which prompted additional studies of scale control in seawater and cooling applications.The studies utilized an evaporative cooling tower technique as opposed to the static or synthetic procedures used in the studies performed in 2000. This enabled evaluation of hydraulic operation together with chemical treatment. The viability of using synthetic seawater as opposed to authentic seawater, which would facilitate conducting a greater number of studies in a shorter period of time, was part of the evaluations performed.It was demonstrated that selection of specific chemistry for scale and deposit control could allow the operation of seawater cooling systems at a higher concentration factor than that which is normally practiced, and potentially reduce or eliminate the use of acid for pH reduction. These findings will assist in reducing the cost of operating and environmental impact of such cooling systems.