Abstract

In open cooling water systems, phosphorus-based (P-based) programs are the most widely used treatment program for corrosion and scale control. Excellent performance of P-based programs has been long proved in many institutional and industrial applications. Despite this high performance, phosphorus is one of the limiting nutrients to bacteria and may accelerate microbial growth if with excess concentration. A recently developed and innovative non-phosphorus (non-P) program has been deployed globally, not only to comply with discharge regulations, but also to provide additional benefits/value to our customers. One feature of the non-P program is to eliminate/reduce phosphorous feed that enhances biological control. First case study of a non-P program is in a microelectronics plant. The new non-P program showed excellent corrosion, scale, and microbiol control performance. Superior performance of corrosion and scale control was demonstrated and is fully understood from a mechanistic perspective. For microbiol control, the bacteria count dropped two orders of magnitude after switching from an incumbent phosphorus-based program to the innovative non-P program. In the 2nd case study, an ethanol production plant recently switched from P-based program to the non-P program to improve the algae control in the discharge pond. After 10+ years suffering from algal bloom at summertime, very positive results have been observed. Moreover, corrosion control was further improved as reported.

Introduction

Cooling water systems are commonly used to cool a process, either steam, gas or liquid, through heat exchangers or condensers in various plants. The heat exchangers or condensers can be corroded easily or have scale and biofilm growth due to the poor water treatment program. The corrosion, scale, and biofilm growth on heat exchangers can lead to significant reduction in heat exchanger efficiency and lifetime. The repair expense or loss of production often costs plants a few hundred thousand or millions of dollars per day for heavy industries, such as chemical and power plants, refineries, and steel mills. Thus, cooling water treatment is critical to maintain the integrity and efficiency of heat exchangers.

Keywords:
pipeline corrosion, corrosion inhibition, materials and corrosion, water management, production chemistry, subsurface corrosion, flowline corrosion, oilfield chemistry, well integrity, nutrient
Subjects:
Production Chemistry, Metallurgy and Biology, Pipelines, Flowlines and Risers, Materials and corrosion, Well Integrity, Subsurface corrosion (tubing, casing, completion equipment, conductor), Corrosion inhibition and management (including H2S and CO2)
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