What is the value in measuring conductivity in a UPW system?
Compiled by Mike Henley and James McDonald
(Editor’s note: This article is based on recent discussions in the LinkedIn Ultrapure Water and Industrial Water Treatment groups. This column seeks to accurately reflect comments from each contributor. On occasion, there may be the need to edit contributor comments for clarity or length. An important purpose of each group is to provide a forum for practical examination of issues facing endusers of high-purity and industrial water.)
Why measure conductivity?
Mike: What is the value in measuring conductivity in a UPW system? What does it tell you?
Nikhilesh: “I would like to share a few examples.
First, in pure water systems, conductivity measurement is the most common indicator of ionic contamination and dissolved solids. For instance, in semiconductor plants where UPW is used as a cleaning agent, the water should not contain dissolved contaminants that can deposit/precipitate, or particles that may sit on circuits and cause microchip failures.
The ionic contaminants are also a source of corrosion. The ionic deposits also can generate electrolytic cells on metallic surface and promote corrosion. The power industry uses UPW to make steam to drive turbines. Any excess dissolved solids over the limit can cause entrainment in the steam and carry over on turbine surface. Many ionic solids are volatile, which can carry over in vaporous form and condense on the turbine, causing scaling and corrosion. In dissolved form, ionic solids are electrolytes that conduct electricity and cause corrosion.”
Bill: “It is difficult to accurately measure pH in pure water, but conductivity will indicate the limits of what pH can be because of the high conductance of hydrogen (forgive the use of the common term) or hydroxide ions compared to other ions.”
Vasanthy: “Conductivity indicates the purity of water in terms of inorganic impurities. It can be an excellent and accurate measuring tool.”
What Is Your Role in UPW?
Mike: So we can become better acquainted, please introduce yourself and tell about your work in high-purity (also known as UPW) water treatment. For this discussion, it is okay to mention business affiliation.
Nick: “Thanks for starting this discussion. I have 5 years experiences in UPW process design. I am in a different industry now, but my two great mentors in UPW taught me how to be a good process engineer and good project manager, and finally a human being. UPW was the start of my career. That's why I keep updating my knowledge on this subject.”
Reimund: “I have more than 30 years of experience in particle counting in UPW, WFI, and other DI-water applications. During this time, I have worked for HIAC/Royco, Particle Measuring Systems, PAMAS, and RION. Another experience I have is with TOC measurement, based on working with Anatel and Sievers. I have used particle counting and TOC measurement in the semiconductor industry and in pharmaceutical production. From 2002 to 2008, I produced "Suitability Test Kits" for Sievers and Anatel (on-line and lab systems). Currently, I represent RION particle counters in Europe and I sell low-TOC vials for TOC measurements.”
Obet: “I'm currently involved in the design and installation of various phases in water treatment—both IX and membrane processes. We install various UPW systems at the 18-megohm level and RO with high-yield recovery. Other IX systems include dealkalizing, dual-bed pretreatment such as iron and manganese removal, as well as turbidity and organic removal, which becomes part of the preliminary treatment. We also design systems for wastewater recovery. Overall, I have more than 25 years of experience. Our company is called Ultrapure Water System Inc. (based in the Philippines).
David: “Greetings. I'm responsible for Ovivo's Electronics and Metals Division in the United States. We provide UPW systems, wastewater treatment systems, and reclamation/recycle systems and services for the semiconductor and photovoltaic industries.”
Eyad: “I am the lead process engineer in the Corodex Group (Dubai, UAE). It is my pleasure to share in this group discussion.”
Richard: “Greetings. I am a field service engineer with 39 years of experience with various companies and am currently with Evoqua Water. I have experience with all types of UPW, but mostly pharma and medical. I am old enough to have worked with old technologies (hollow-fiber membranes) and most of the new ones. I am also a past Ultrapure Water Journal author.”
Mike: “Good to hear from you, Richard. Thanks for introducing yourself. We've appreciated your contributions over the years.”
Rick: “At the moment, I am independent. I have designed and evaluated/troubleshot multiple UPW, potable, process, wastewater systems from inlet to outlet (pretreatment, membranes, post-treatment and distribution) over my 35 years in the industry.”
Anders: “I am an independent consultant and have worked with design, installation, commissioning, and qualification of water systems within pharma for 20+ years. I am a coauthor of some of the ISPE publications and member of the ISPE Critical Utilities Steering Committee.”
Jon: “I'm the CFO of a start-up company that is about to commercialize its distillation technology for use at industrial facilities.”
Shoebz “I am the founder of specialized pharma water company, CN Water Systems, which has been in the Indian market for more than 25 years. Our organization is responsible for complete life cycle solutions for high-purity water (HPW) systems, including design engineering, manufacturing, installation, commissioning, qualification, plant operations, maintenance, compliance management, and asset replacement. My passions are process engineering and troubleshooting, and managing microbiological risks in the Indian context.”
Johan: “I am owner and managing director of the Pure Water Group (based in the Netherlands). Internationally, we supply to water system integrators (OEMs) our electrodeionization and other high-purity and UPW equipment. Our typical markets include power, semiconductors, pharmaceutical and renal dialysis. Next to UPW applications, we also explore opportunities for the Ionpure NexED Electro Dialysis technology. Our support team enjoys collaborating with clients on these specific technologies and applications.”
Christine: “Good day to you all. I am the administrator for the Orlando, FL, branch of Evoqua Water Technologies— High-Purity Division. I feel privileged to have been accepted among what I see is a huge group of industry Big Wigs! My hope is to seek out a greater knowledge of the water business, and learn from each of you.”
Barbara: “I have more than 30 years of experience in operation, design, and process engineering of water treatment and high-purity systems. My experience includes process, design and consulting for major microelectronics and semiconductor manufacturers. I spent most of my career at IBM/Hitachi as the expert resident in water treatment. Presently, I work as an independent consultant. I enjoy reading and learning about work of my peers.”
Industrial Water Treatment Discussion
Compiled by James McDonald
Dealing with Oily Condensate
James: What should one do when oily condensate is being returned to a low- or medium-pressure boiler?
Ashwini: “Immediately isolate the line from where oily condensate is coming. It may be from gland steam if connected to a condenser. It may be condensate coming from process plant through a condensate recovery system such as pressurized and pumping unit. Try to overflow the deaerator if possible to increase make-up demineralized water. Increase blowdown and phosphates and check oil content of blowdown water. If oil in the condensate is too high, then foam comes out from the deaerator vent. In such a situation, one may shut down the boiler; otherwise, foaming in the boiler may take place that may be detrimental to the turbine as well as the super heater. It is necessary to have an oil check with a condensate polishing unit at certain intervals to avoid such situations.
Apart from foaming and carryover, oil film can reduce heat transfer so there is a chance of overheating of boiler tubes and failure of the pressure part of the boiler may occur, even it is a low-pressure boiler and there is no steam turbine. Condensate has to be checked at regular intervals before or at the feedwater tank, and before the deaerator. Oil in the condensate causes heavy fouling on the water side and raises temperature on the fire side, so there is a possibility of bursting/explosion. It is better to shut down a boiler if oil in the boiler water is high. After a thorough cleaning of the water side of boiler to ensure no further ingress of oil in the condensate, the boiler may be restarted.”
Nikhilesh: “I have experienced a similar problem in a fatty acid distillation plant many times. The detection of small leaks in the heat exchange (HX) was not easy because of tube-side (fatty acid) pressure being less than the shell-side steam pressure. The HX steam trap condensate had undetectable oily substance. The only thing that changed was the appearance of the fatty acid that we could see through the sight glass. It turned into a whitish emulsion. In every HX (oil/water) piece of equipment, it is a challenge to detect these leaks at an early stage and take appropriate action.”
KV: “There should be an on-line TOC analyzer that will trigger opening and dumping of the condensate. The next step would be isolation of the source.”
Worawat: “It will break down to organic acid in boiler and cause a dropping pH. It is helpful to add chemicals to maintain a high pH to prevent corrosion and then work to find and eliminate oil leaking.”
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