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Issue 05 / 06 (2022)

Alkalisation and pH Stability in Water-Steam Cycles

Wolfgang Hater

The pH adjustment in the water-steam cycle is an important and widely applied measure to maintain plant integrity. The impact of the most common alkalising agents on pH and conductivity is discussed as well as the behaviour of mixtures. A methodology to calculate pH and conductivity from base constant and equivalent conductivity including possible intrusion of acid substances is presented.

With increasing basicity of the alkalising agent, the molar quantities needed to obtain the desired pH value decreases, reaching the minimum value for sodium hydroxide. At the same time, the impact of an ingress of an alkaline or acidic substance increases. Of the alkalising agents discussed in this paper, ammonia shows the highest and sodium hydroxide the lowest stability against pH excursions.

Mixtures of alkalising agents change their properties with regard to pH stability linearly as a function of the composition. Their pH stability reflects the properties of the individual components: a mixture of sodium hydroxide and ammonia has a lower resilience against acid ingress compared to mixtures of trisodium orthophosphate and ammonia.

A high pH stability of the alkalising agent is an important measure to reduce the possible impact of acidic substances entering the system by leakage or decomposition of organic matter. Therefore, this has to be carefully considered when choosing the chemical for alkalisation

PPCHEM® 2022, 24(5,6), 196–206

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Some Brief Comments on Microbiologically Influenced Corrosion (MIC) in Power Plants

Reza Javaherdashti

This article deals with the most practical aspects of microbially influenced corrosion (MIC) in power plants. The issues discussed here are mainly where to expect MIC in power plants, the inaccurate nature of the term “biofilm” and the possibility of whether bacterial adaptation to biocides can occur. These issues are particularly important from an operation and maintenance point of view because they play an undeniably significant role in reducing the useful service life by increasing the risk of MIC and the cost of its treatment in power plants.

PPCHEM® 2022, 24(5,6), 208–213

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Oxidative Treatment of Waste Containing EDTA for its Safe Disposal – Choice of Oxidant and Mode of Addition for Field Applications

Rajini P. Antony and A. L. Rufus

High amounts of ethylenediamine tetra acetic acid (EDTA) containing liquid waste along with metal ions (predominantly iron) at pH ~ 8 are generated during the process of chemical cleaning of steam generators in pressurized heavy water reactors and pressurized water reactors. Hence, proper waste disposal involving complete or partial decomposition of EDTA is indispensable. Three different oxidants, viz., air, H2O2, and ozone, were explored for the decomposition of a test solution. Their efficacy was found to be in the order: H2O2 > ozone > air. The lower rate of decomposition in the case of ozone and air is due to their solubility limitations. Investigations on the mode of addition of H2O2 revealed that a bulk/one-time large addition of H2O2 and continuous addition of small quantities at a controlled flow rate yield identical results. On weighing the practical risks/hazards involved in bulk addition during field applications, continuous addition is suggested as a better option.

PPCHEM® 2022, 24(5,6), 214–223

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Industrial Plants and Steam Purity for Turbine Operation – A Too Frequent and Almost Classic Dilemma

Michael Rziha

Worldwide there are countless industrial installations using steam as a “byproduct” to drive a steam turbine. The steam is generated by many different sources, such as quench boilers and trans-line-exchangers, which are often found in refineries and petrochemical plants. Waste heat boilers in refineries and petrochemical plants can be water tube boilers and shell boilers. Fired flame tube boilers with low or medium pressure (5–50bar) are also used in many installations.

Industrial steam generators often have special requirements regarding load gradients (extremely fast load requirements and/or load reduction). Process steam extraction and process steam condensate return are very common in these plants, and carry the additional risk of the ingress of various contaminants from the different processes, finally leading to a heavy impairment of the steam purity.

Guidelines which are applicable for the feed- and boiler water for the different boiler types and operating pressures are misleadingly taken as “lead documents” although they do not provide the special individual consideration needed for steam purity. It must be emphasized that all such guidelines and standards are only valid for safe boiler operation, and do not address the needs of steam turbines.

In consequence, low-pressure boilers are often operated with softened water. From the perspective of boiler suppliers and boiler operators this might certainly be correct, as the generated steam is used for heating only, where the requirements on steam purity may be more relaxed.

However, and without exception, as soon as the steam is to be used to drive any kind of steam turbine, the relevant standards and guidelines for steam need to be followed. As a matter of principle this will always have an impact on the make-up water, feedwater, and boiler water purity. For example, boilers with a low operating pressure are allowed to be operated with softened or partially demineralized water. This is true and correct for the boiler/steam generator, but it is definitely wrong for any steam turbine tied into this process.

Steam turbine users should be aware of the risks associated with contaminants of the steam, which may initiate, promote, or enhance stress corrosion cracking, corrosion fatigue, general corrosion, erosion, and deposit buildup. Contaminants that are contained in steam generally lead to deposits and corrosion in steam turbines and thus potentially negatively affect their functioning and operational safety, as well as their lifetime. It must also be emphasized that corrosion and/or deposit build-up and consequently damage and/or impairment of performance or availability depend not on the size of the turbine, but only on the impurity level and composition of the steam.

Especially when softened water is used, the concentration of sodium in the water is significantly increased by the softening process! The thermal decomposition of sodium carbonates and sodium bicarbonates (products due to softening) always leads to the formation of caustic soda (NaOH), which strongly increases the risk of alkaline stress corrosion cracking of the turbine material! Consequently, when softened water is used as make-up water, a steam turbine operation is clearly excluded!

PPCHEM® 2022, 24(5,6), 224–229

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Report on the Power Cycle Instrumentation Seminar (PCIS) Austria 2022 in Linz, Austria

Tapio Werder

For the first time in the history of these events, the Power Cycle Instrumentation Seminar (PCIS) series stopped over in a German-speaking country. The PCIS Austria 2022 in Linz was held under the patronage of PPCHEM AG, and SWAN Analytical Instruments provided financial support.

Since 2012, PPCHEM AG and its precursor organization, Waesseri GmbH, have organized more than 30 conferences and seminars around the world with the mission of expanding the knowledge of cycle chemistry and the understanding of analytical instruments. Over the past 10 years, different formats of events have been developed to fit the different needs and interests within the power plant chemistry community.

This report summarizes the two days of the PCIS Austria 2022

PPCHEM® 2022, 24(5,6), 238–240

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Issue 04 (2022)

Dechlorination Control and Optimization in Industrial Water Applications

Vadim Malkov and Gregory Fleck

The use of reverse osmosis (RO) membranes for water treatment has almost doubled in the last five years [1]. The use is widespread across many industries, from municipal water and wastewater treatment to ultrapure water production in various industrial applications. For efficient RO membrane operation, it is important to accurately monitor and control the residual chlorine concentration in the feedwater, which allows for minimizing of RO membrane maintenance and extension of membrane life. Multiple studies demonstrate that prolonged exposure of RO membranes to free chlorine exceeding 38 μg · L–1 (ppb) (based on 1 000 mg · L–1-hours over three years [2]) is detrimental to the membrane structure and integrity, while the absence of the disinfectant and/or excess of dechlorinating agents promotes biofouling and causes loss of recovery. To maintain this delicate balance, membrane operators must accurately monitor oxidant concentration and addition of bisulfite, especially in the RO feedwater.

PPCHEM® 2022, 24(4), 136–159

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Causes and Effects of Insufficient Steam Purity and the Necessary Measures

Michael Rziha

As is well known, contamination in the steam very quickly leads to impairment of the steam turbine, ranging from loss of efficiency to a massive reduction in service life, or even to rapid destruction.

The causes and sources for the entry of contamination are very diverse, especially in industrial plants. Plant-specific knowledge of the possible entry points and the types of possible contamination is of crucial importance for the determination of a suitable monitoring strategy for the most trouble-free and damage-free operation of the steam turbine.

In addition, if such contamination occurs, suitable measures must be taken very quickly in order to avoid long-term, undesirable and, above all, cost-intensive damage to the steam turbine.

The most common sources and causes, their detection, and recommendations or necessary avoidance strategies from the perspective of power plant chemistry are presented.

PPCHEM® 2022, 24(4), 164–169

For Members only

HINTS FROM THE EXPERTS

Saving Money with Clever Blowdown Management

Clean chemical conditions within the water-steam cycle and the steam generator systems are of utmost importance for trouble-free operation and to maintain the required steam purity for steam turbine operation. If the control of the chemical regime is not managed correctly, the introduced contaminants will lead to the build-up of layers on the blading of the turbine, reducing steam turbine efficiency and leading to corrosion processes which can cause considerable damage in the water-steam cycle and steam generator systems. In the worst case the steam generator or the turbine will be reduced to scrap metal.

To control these contaminants and to avoid an excessive concentration within the evaporator, the blowdown of evaporator water is used to keep the concentration of the contaminants within allowable limits.

However, this method of concentration limitation has the negative side-effect of a loss of valuable enthalpy. It also increases the consumption of demineralized water and chemicals.

PPCHEM® 2022, 24(4), 170–173

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Application of Chloramine as a Biocide for Cooling Tower Water Consumption Reduction

Anderson José Beber

This paper shows the results of the application of a mild oxidizer on a large cooling tower at a power plant in southern Brazil. This cooling tower utilizes grey water (tertiary treated domestic sewage) as make-up. With the application of this technology, there was an improvement in both microbiological control and corrosion rates. Additionally, the plant was able to increase the concentration cycles from an average of 4.5 up to 6.5, resulting in an annual savings of over 400 000 USD.

PPCHEM® 2022, 24(4), 174–182

For Members only

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Issue 03 (2022)

Sampling and Monitoring – The Daily Routine, Which Is Anything but Trivial or Simple

Michael Rziha

This article highlights some crucial and essential topics related to sampling and monitoring and how to obtain correct and representative samples and useful results.

Some classic mistakes; still experienced today in numerous plants; are highlighted as well.

Hints are given on how to avoid such mistakes and how to minimize the bias of samples. This article focuses on the most important basic rules for correct and representative sampling; but also draws attention to the most common mistakes being made.

PPCHEM® 2022, 24(3), 96–103

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Tribute to Ken Galt

It is our sad duty to inform you that Ken Galt passed away on May 1, 2022. He had been a member of the International Advisory Board (IAB) of the PPCHEM journal since the summer of 2020. Ken Galt was an outstanding scientist in the field of power plant chemistry, contributing a wealth of valuable research findings, notably studies on many topics.

PPCHEM® 2022, 24(3), 108

HINTS FROM THE EXPERTS

Making Control Loops Smarter

For some applications in power plants; it is not a good option to wait until control loops reach the setpoint based solely on the reaction to the control deviation over time; as this may cause activation of warning signals or; in the worst case; may even trigger protection commands due to a delay in reaching the required setpoint. Some control loops are additionally susceptible to undesired oscillations. Hence; these affected control loops should be made smarter; so they behave more stably and react faster.

How this can be easily achieved is explained here with various examples.

PPCHEM® 2022, 24(3), 118–119

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Foundation of the German-Swiss Association for the Properties of Water and Steam (GSAPWS) on April 1, 2022, in Potsdam, Germany

On 1 April 2022; 13 delegates met in Potsdam; Germany; for the founding meeting of the German Swiss Association for the Properties of Water and Steam. This meeting was also the first in-person meeting of the German and the Swiss National Committees since the start of the Covid-19 pandemic.

PPCHEM® 2022, 24(3), 120–121

Press Release: Last Regular Meeting of the VGB Working Group LWR-Chemistry at the NPP Emsland

Dr. Timo Stoll & Jörg Fandrich

On May 3–4; 2022; the last regular meeting of the VGB Working Group Light Water Reactor (LWR)-Chemistry took place at the nuclear power plant (NPP) Emsland; Germany. In addition to the technical experts of most of the German nuclear power plants; experts from all the Swiss nuclear power plants; the Netherlands; Spain and Belgium as well as from Framatome GmbH as consulting plant manufacturer participated.

PPCHEM® 2022, 24(3), 122–123

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Issue 02 (2022)

Conductivity Limits for Direct Water-Cooled Generators

Robert Svoboda and Wolf-Dietrich Blecken

For normal operation, a conductivity limit of ≤ 0.2 μS · cm–1 is an indirect indicator of correct pH and restricts undue corrosion. With protective additives, e.g., NaOH for alkaline treatment, a higher limit corresponding to the objective of the treatment is appropriate.

With too high conductivity the water inside the insulating hoses of high-voltage stator windings will warm up and if it boils there is a risk of electric flashover inside the insulating hose with damaging consequences. Therefore, a short-term action limit in the order of 10 μS · cm–1 has been set by the industry in the past.

With correct water flow, conductivity inside the insulating hoses at these values does not warm up the water significantly and there are no restrictions regarding the duration of such an event.

However, when cooling water flow is lost, the water inside the insulating hoses will warm up exponentially with time. The time until boiling has a strong (square) dependence on the rated generator voltage, as well as on the insulating hose length, and has a linear dependence on water resistivity. The spatial position of insulating hoses (hoses are mounted vertically, horizontally, or bent) is also of importance. In addition, the stationary cooling water inside the stator bars, as well as the entire stator winding, is subjected to critical temperatures, especially at high load conditions. Therefore, appropriate action must be taken prior to reaching the water boiling level. To avoid a costly stator winding breakdown, the cooling water flow must be restored at once. Otherwise, the generator has to be shut down completely as soon as possible.

PPCHEM® 2022, 24(2), 52–63

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Avoidance of Common Mistakes during Failure Analyses and Misinterpretation of Lab Results – Part 2: Lab Analyses / Sample Handling, Preparation, and Analytical Procedures

Frank Udo Leidich

For a proper failure analysis or root cause analysis (RCA), a great deal of data and evidence-based information is needed. Within this context, various types of samples from different locations need to be taken for chemical and/or metallurgical examination. In addition to proper and correct sampling without alteration of the composition or contamination of the samples, which is described in the first article of this short series [1], it is of utmost importance to use the right analytical methods and execute sample preparation carefully. This includes being aware of the basic principles of the methods applied and of course knowing their limits. This article discusses the analytical part of an RCA and is the second part in a short series of ongoing articles.

PPCHEM® 2022, 24(2), 70–75

For Members only

HINTS FROM THE EXPERTS

Considerations for the Control of the Dosing of Trisodium Phosphate (Na3PO4) in Boiler Water

In the recent past, various organizations have been trying to establish a more or less full automatization of the dosing control for the phosphate boiler water treatment (typically called PT), similar to the well-established and well-functioning automatic dosing control of ammonia. Although this may sound easy, as nowadays very reliable instruments and sampling systems are available, it is relatively difficult to implement, especially for PT, as the entire phosphate chemistry is very complex compared to that of ammonia. Therefore a safe and reliable automatic control of PT involves a lot of traps and risks which must be considered. The most common and challenging issues in this respect are described here. Although this list may not be complete, it could be used to reconsider the idea of fully automated control of phosphate dosing.

PPCHEM® 2022, 24(2), 76–81

For Members only
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Issue 01 (2022)

Deviation in Turbidity Readings at a Low Range

Irene Rüegg

Various factors contribute to deviations encountered in low turbidity readings by different analyzers. Turbidity measurement is instrument-dependent; different instruments calibrated with formazine according to the standard methods only show identical readings on a sample if the instruments incorporate the deviation factors. This article examines the interferences that affect a “zero” measurement and demonstrates how the concept of the Swan AMI Turbiwell turbidity analyzer reduces these inaccuracies.

PPCHEM® 2022, 24(1), 4–8

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Cleaning of Newly Erected Steam Boiler Plants and Associated Pipework

Wolfgang Rost

Experience gained over the years has shown that the strict adherence to prudent industry practice regarding the clean assembly of steam generator and water/steam cycle systems is the key to quickly establishing normal and trouble-free steam turbine operation of newly built power plants. It is therefore most valuable to understand what kinds of contamination can occur in what production step, what adverse consequences they imply, and how to generally avoid them by setting up very simple guidelines to start with. In addition, it is very helpful to know what sort of remedies exist as effective corrective measures if things go wrong in the first place. The knowledge of what state-of-the-art cleaning procedures exist and how they are conducted properly is also a very important key to success. If all the aforementioned points are adhered to, a reduction in execution time and money expenditure will be the result at the end of the day.

PPCHEM® 2022, 24(1), 10–23

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Review – vgbe Chemistry Conference 2021

Andreas Wecker and Sabine Kuhlmann

The 57th vgbe Chemistry Conference took place again as an attendance event. As usual, this chemistry conference was also accompanied by a trade exhibition with 21 national and international exhibitors. The approximately 160 participants were offered an interesting lecture programme.

PPCHEM® 2022, 24(1), 28–29

HINTS FROM THE EXPERTS

How IAPWS-IF97 can be used to optimize the so-called “Cleaning Force Ratio” during the steam cleaning of power plants


Throughout the entire process of the fabrication and construction of newly erected power plants, contaminants are introduced into the systems of the steam generator and the water/steam cycle due to the nature of the work. Some of these contaminants may not be removed successfully during chemical cleaning. Thus, due to the cleanliness requirements regarding the absence of particles, steam systems of power plants must undergo steam-blow operation prior to commencing the first steam admission to the turbine.
Therefore, all steam pipes routed to the steam turbine must be steam-blown by using enough “force” to remove solid contaminants effectively. The so-called “Cleaning Force Ratio” (CFR) is used to determine whether this required “force” is achieved during steam cleaning.

PPCHEM® 2022, 24(1), 30–31

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2021’s Scientific and Technical Contributions

PPCHEM® 2022, 24(1), 32–40

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Issue 06 (2021)

Human Performance & Cycle Chemistry – The Missing Link? Part 2

Brad Burns and Doug Hubbard

On most units assessed by the Electric Power Research Institute (EPRI) across the world, cycle chemistry is well controlled and good results are obtained 99.9 % of the time. Fossil and combined cycle power plants on a global scale continue to boast higher cycle chemistry benchmarking scores, installation of new instrumentation and alarming, and management support for cycle chemistry. The exception, however, continues to be major cycle chemistry excursion events that happen infrequently, yet with great consequences.

Often, when an unmitigated major cycle chemistry upset event occurs, root cause investigations pin the event on inadequate skills or knowledge (of individuals). It is therefore believed that additional training and/or disciplinary corrective action solves the root cause of the event and will prevent poor operator response to out-of-spec chemistry from recurring.

But does this approach produce the desired results? This article continues part 1, which was published in the January/February 2021 edition of this publication. Human performance improvement was described as the potential “missing link” to achieve true cycle chemistry improvement. This article builds upon the previous one by providing practical examples and suggestions for implementing improved defenses in a plant.

PPCHEM® 2021, 23(6), 242–251

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The Economic Benefits and Goals of Power Plant Chemistry

Frank Udo Leidich and Michael Rziha

Thus far, the chemist in a power plant has quite often been regarded as a necessary evil or as inevitable costs. The purpose of this paper is to explain the economic benefits of a chemist, the need to have a specialist on the operation team, the purpose and goals of the job, and the expectations of the chemist from the power plant management’s point of view.

Of course, the economic impact, the possible risks, and (monetary) damage that might arise if the job is not done as it should be are discussed here as well.

This paper concentrates on the goals and purpose of the chemist’s activities regarding the water/steam cycle and the components therein. Future papers will also deal with the chemist’s footprint on the cooling system, including the cooling water make-up system, the flue gas path, and the treatment of other systems and machines.

PPCHEM® 2021, 23(6), 254–263

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Accuracy, Trueness and Precision of Measurement Methods and Results

Michael Rziha

The present paper is an updated revision of a paper presented 22 years ago at the joint European NUSIS-ICMG-VGB Chemistry Online Process Instrumentation Seminar in Brügge, Belgium (April 20–22, 1999).

The original paper was prepared by Dr. J. Fahlke, Grosskraftwerk Mannheim, Mannheim Central Power Station, Mannheim; W. Fichte, Consultant, Ismaning; E. V. Maughan, Tablar Messtechnik, Duisburg; H. D. Pflug, Consultant, Bergen-Enkheim; and H.-G. Seipp, ABB, Mannheim – all located in Germany.

I would like to express my sincerest thanks to Dr. J. Fahlke for providing me with the original paper and permitting me to use it as the basis for this updated version.

This paper is an attempt to facilitate understanding of the rather abstract and in part complicated definitions of the ISO 5725 by combining them with some illustrations. This approach, although it may require getting used to, will help to promote a better understanding between manufacturers, suppliers, purchasers and operators of continuously operating measuring instruments in plant cycle chemistry.

PPCHEM® 2021, 23(6), 264–270

For Members only

PPCHEM Interview with Wolfgang Rost

Tapio Werder

Wolfgang Rost joined the PPCHEM team in October 2021 as Senior Key Expert for Power Plant Technology. Tapio Werder, Editor in Chief of the PPCHEM® journal, has interviewed Wolfgang to introduce him to our readers.

PPCHEM® 2021, 23(6), 272–274

For Members only
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Issue 05 (2021)

Considerations for Complex Industrial Cooling Water Monitoring and Treatment

Brad Buecker and Rajendra P. Kalakodimi

Heat exchangers are, of course, a critical component of power and heavy industrial plants. Many of these are water cooled, with the source being a cooling tower (commonly known as an open cooling system) or sometimes once-through cooling. Often, “closed” systems are also present, which are cooled by primary heat exchangers, but whose chemistry is significantly different from that of open systems. Successful chemical treatment of the wide variety of cooling systems in plants requires analysis of many factors, including the potential for corrosion, scaling, and microbiological fouling, system metallurgy, operating temperatures, and others, all of which are examined in this article. Also discussed are several significant improvements to chemical treatment programs in recent years, improvements that maintain proper heat transfer and reliability of cooling systems.

PPCHEM® 2021, 23(5), 198–205

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Weighted Salt Hours – A New Approach in Cycling Plants

Frank Udo Leidich

Thus far, the chemist in a power plant has quite often been regarded as a necessary evil or as inevitable costs. To leverage the activity of the power plant chemist and make his/her work observable and tangible in an economic sense to the management, it is proposed to introduce a new parameter, weighted salt hours, that can be used to link the key chemistry parameters with key economic performance indicators. To do this, data mining and application of statistical methods, like gauging of repeatability and reproducibility, multifactor analysis, and others analyses, are needed. Of course, such efforts can only be successful if a very high number of power plants participate and contribute to this.

PPCHEM® 2021, 23(5), 206–210

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Flexible Operations in the Energy Transformation: High-Level Impacts on Cycle Chemistry

Mike Caravaggio

Electricity generation is changing, and these changes impact all aspects of the plant. The following paper sets out some of the key changes and the high-level impacts on cycle chemistry in thermal plants. It is incumbent upon power plant chemists and chemical engineers to understand the details of how flexible operation affects their specific units, so that they can develop optimal, unit-specific solutions.

PPCHEM® 2021, 23(5), 212–220

For Members only

Assessing Corrosion in Air-Cooled Condensers at Eskom Medupi Power Station

Sabelo Khanyile, Stephanie Marais, Setsweke Phala, Zanele Dladla, and Nestor van
Eeden

Steam side surfaces of air-cooled condensers (ACC) are prone to corrosion. If the
corrosion mechanism is not understood and mitigated, it can lead to ACC tube failure(s),
and subsequent vacuum and/or condensate chemistry deterioration. Most importantly, the
total iron levels entering the condensate and feedwater systems will be much greater than
international guidance. This paper reports on the ACC corrosion assessment performed on
Unit 5 of Medupi power station. The ACC condensate chemistry is reviewed and the
“Dooley Howell ACC Corrosion Index” is reported. The latter was derived from the physical
inspections of the internal surfaces of the ACC. The inspections were conducted when the
unit was on all-volatile treatment, under oxidising conditions (AVT(O) regime), as well as
after transitioning to an oxygenated treatment (OT) regime. The benefits of transitioning
from AVT(O) to OT are also reported.

PPCHEM® 2021, 23(5), 222–228

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Issue 04 (2021)

Monitoring Industrial Plant Discharge Metals and TOC

Brad Buecker and Ken Kuruc

Industrial facilities such as refineries, petrochemical plants, steel mills, metal finishing facilities, pulp and paper mills, pharmaceutical plants, etc. require substantial wastewater treatment, as some processes at these facilities can release many complex carbon compounds or other toxic constituents, including metals, to waste streams.

While various techniques are available for measuring trace level metals in process water, to date they have been rather unavailable to many industrial locations because of capital cost requirements or the need for specially trained technicians. Two well-known techniques are inductively-coupled plasma and atomic absorption spectroscopy, which need specially trained operators and require complex sample preparation and expensive instrumentation.

This article discusses another existing technology, colorimetry, which has been modified for on-line monitoring. The method is suitable for many facilities and can be operated by a wide range of plant personnel. In many cases, the readings can be enhanced with TOC analyses to provide additional protection for industrial water/steam systems.

PPCHEM® 2021, 23(4), 152–157

For Members only

Film Forming Amines – An Appraisal

Wolfgang Hater

The technology of film forming amines or more generally film forming substances in water treatment has been well known for decades. The acceptance of their application in watersteam cycles was significantly increased by two IAPWS Technical Guidance Documents issued in 2016 and 2019. These documents provide a brief synopsis of the scientific knowhow, and, more importantly, give practical guidance to people interested in this technology. This paper reviews and summarizes the scientific progress since then and identifies further research needs. Film forming substances have an important potential for the reduction of plant emissions, which, in addition to the demand for molecules with improved environmental properties, is looked upon as a driving force for future development.

PPCHEM® 2021, 23(4), 162–175

For Members only

Conferences and Seminars Organized by PPCHEM AG – An Overview

Tapio Werder and Michael Rziha

Since 2012, PPCHEM AG and its precursor organization, Waesseri GmbH, have organized more than 30 conferences and seminars around the world with the mission of expanding the knowledge of cycle chemistry and the understanding of analytical instruments. Over the past 9 years, different formats of events have been developed to fit the different needs and interests within the power plant chemistry community.

The first kind of event series developed was called Power Cycle Instrumentation Seminars (PCIS), with the mission of expanding the knowledge of cycle chemistry and the understanding of sampling techniques and analytical instruments. Based on the feedback from the PCIS participants a new series of events – PowerPlant Chemistry Forums (PPCF) – was introduced in 2016. Compared to the PCIS the PPCF does not concentrate exclusively on sampling and instrumentation, but instead includes a wide variety of nearly all aspects of power plant chemistry, such as life-cycle chemistry optimization, start-up chemistry and early operation experience, and plant failures and subsequent chemistry adjustments. The forum is basically a typical conference, where numerous international speakers from many different organizations present, hence it is a platform for all participants to exchange information and knowledge and for networking.

Beside the PCIS and the PPCF, educational seminars have also been developed and offered. These seminars are typically focused on a “hot topic” from power plant chemistry and usually they are conducted by PPCHEM’s chief key expert power plant chemistry Michael Rziha.

This contribution outlines the developments in the past years and gives more details on the different formats of events which are currently organized by PPCHEM AG.

PPCHEM® 2021, 23(4), 180–185

For Members only

PRESS RELEASE: EPRI 13th International Conference on Cycle Chemistry in Fossil and Combined Cycle HRSG Plants (ICCC13): Details Advances in R&D

EPRI’s 13th International Conference on Cycle Chemistry in Fossil and Combined Cycle HRSG Plants was conducted virtually June 22–24, 2021.

The conference was attended by 146 different professionals representing 10 countries, including Australia, Canada, Malaysia, Philippines, Taiwan, South Africa, Switzerland, United Kingdom, United Arab Emirates, and the United States.

The EPRI Boiler and Turbine Steam and Cycle Chemistry R&D program (Program 226) conducts collaborative research led by Program Manager Brad Burns. The collaborative program is a global leader in comprehensive research in power plant steam and water cycle treatment to minimize corrosion and deposition.

The conference is hosted by EPRI every three years. This latest event featured 21 presentations by international experts, equipment manufacturers, chemical suppliers, and power plant chemistry users. Discussions on a wide range of cycle chemistry-related topics added participation value to plant users, equipment and chemical suppliers, and researchers.

PPCHEM® 2021, 23(4), 186–187

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Issue 03 (2021)

Avoidance of Common Mistakes during Failure Analyses and Misinterpretation of Lab Results – Part 1: Sampling

Frank Udo Leidich

For a proper failure analysis or root cause analysis (RCA) a great deal of data and evidence-based information is needed. Within this context, various types of samples from different locations need to be taken for chemical and/or metallurgical examination. Therefore, proper and correct sampling, without alteration of the composition or contamination of the samples, is of utmost importance. Unfortunately, this is often not practiced correctly and so the risk of incorrect conclusions is high. This article is intended to help personnel obtain these samples in a proper manner and avoid common and repeated mistakes.

PPCHEM® 2021, 23(3), 108–119

For Members only

Update on Predicting RIHT Using the UNB-CNER CANDU-6 PHT System Model

Olga Y. Palazhchenko, William G. Cook, Alex L. Martin, and Jennifer Lennox

Reduced heat transfer in CANDU steam generators has safety consequences such as lower margins to fuel dryout due to higher reactor inlet header temperature (RIHT). To identify methods to maintain the RIHT within operational margins, it is necessary to model the effect of thermal degradation mechanisms on boiler heat transfer.

A comprehensive steam generator heat transfer and fouling add-on has been developed at the University of New Brunswick, Canada, and previously benchmarked using historic data from Point Lepreau Nuclear Generation Station. The one-dimensional, steady-state heat transfer code mechanistically predicts the effect of primary-side fouling, and semi-empirically models the effects of divider plate leakage and secondary-side fouling. This paper presents the most recent predictive modelling, where simulations of post-refurbishment operation (2012–2042) were conducted based on the benchmarked mechanisms. The predictive simulations inform the timeline for mitigating strategies such as a primary-side clean during the plant’s operating lifetime.

PPCHEM® 2021, 23(3), 122–131

For Members only

IAPWS Seventh Meeting of the European HRSG Forum (EHF2021)
Highlights and Press Release

Barry Dooley and Bob Anderson

The seventh annual IAPWS European HRSG Forum was held on the 18th and 20th May 2021 as a virtual event. It was chaired by Barry Dooley of Structural Integrity and Bob Anderson of Competitive Power Resources. EHF2021 attracted 90 participants from 17 countries and included 55 users.

EHF is supported by the International Association for the Properties of Water and Steam (IAPWS) and is held in association with the Australasian Boiler and HRSG Users Group
(ABHUG) and the US HRSG Forum (HF). The 2021 EHF had two sponsors: Trace Analysis and Swan Analytical Instruments. The conference was organized by PPCHEM AG.

PPCHEM® 2021, 23(3), 132–133

ATP Testing – A Real Time Monitoring of Microbiological Growth in the Cooling Water Systems of Power Plants

Kiran Diwakar, Rajendra K. Saini, Upain Kumar Arora, Janakiraman Pattabhiraman, and Gopi Kanta Nayak

In power plants, the warm environment of recirculating cooling systems is ideal for the growth of microorganisms. As microorganism communities grow in cooling systems, they can attach to tubes, pipe walls, and cooling tower fills, and form biofilms. Uncontrollable biological growth causes fouling, loss of heat exchange capacity, equipment failure, and energy wastage.

Due to the large volume of a cooling system with a flow rate of 60000–75000m3·h–1 (500 MW plus unit) and the diverse types of bacteria, spores, and algae, no one chemical can kill everything. There must be proper selection of a biocide, adequate contact time, and real time monitoring techniques to allow control of biological problems.

The best solution for any system is the fast and early detection of biological contamination, and the setting up of proactive actions and subsequent corrective treatments. For the measurement of microbiological counts, we can use culture tests like the heterotrophic plate count (HPC) method. However, these culture tests only measure culturable organisms while adenosine triphosphate (ATP) testing measures all microorganisms within a sample. There are two types of ATP – intracellular ATP contained within living biological cells and extracellular ATP located outside of biological cells, which has been released from dead or stressed organisms.

In one thermal power plant cooling water system of NTPC Ltd., India, this technique was demonstrated with successful results.

PPCHEM® 2021, 23(3), 134–142

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Issue 02 (2021)

Ngati Tuwharetoa Geothermal Assets Ltd Reboiler Plant Water/Steam Chemistry Improvements to Resolve Ongoing Corrosion Issues and Prevent Future Tube Failures

David Addison, Nik Vandervegte, and Nellie J. Olsen

Since its commissioning in 2010, the Ngati Tuwharetoa Geothermal Assets Ltd Kawerau reboiler plant has suffered from major corrosion and plant failure issues. Corrosion-related failures which occurred due to water/steam chemistry issues and interactions with plant materials have led to premature complete replacement of the tube bundles.

In 2018 a major root cause analysis was undertaken into the failures that included a detailed chemical and metallurgical investigation and successfully identified the failure mechanisms. A number of simple chemical treatment changes, including hydrogen sulfide neutralisation, pH correction and the application of corrosion inhibiting film forming substances, were carried out to successfully mitigate ongoing corrosion of the plant and to significantly extend asset life.

PPCHEM® 2021, 23(2), 56–72

For Members only

A Novel Combination of CMIT/MIT with a New Non-biocide Dispersant in Cooling Tower Biofilm Control

Henk A. Jenner

Microbial biofilm communities are a significant problem in recirculating cooling water systems resulting in reduced heat transfer efficiency, and the risk of microbial influenced corrosion (MIC) and Legionella infection of operators. Most biocides are generally only effective in the control of microorganisms when in the water phase. A new dispersant was tested that is able to remove biofilms from their substrate, releasing the biofilm community into the water phase. This study investigated how the effectiveness of (chloro)methylisothiazolinone/methylisothiazolinone (CMIT/MIT) (non-oxidizing biocide) in a heavily fouled scale cooling tower model with condenser tubes could be improved by the new dispersant. Dosing tests with CMIT/MIT separately and combined with the new dispersant were performed with different CMIT/MIT concentrations. Microbial activity in both water samples and biofilm samples was measured by the analysis of adenosine triphosphate (ATP). Additionally, the biofilm mass in the transparent condenser tubes was visually inspected by photos. The new dispersant was shown to be effective in loosening the biofilm and the biocidal efficacy of CMIT/MIT was greatly increased due to this combination.

PPCHEM® 2021, 23(2), 74–81

For Members only

Online Analysis of Film Forming Amines

Harold Stansfield

Waltron has developed an online colorimeter for online analysis of film forming amines
(FFA). The design basis and development process are discussed. Data from beta testing and two working case studies are presented. The analyzer can monitor FFA-based products in a working range of 0–1 000 µg ⋅ L–1, with an accuracy of ± 2 % of full scale or ± 5 µg ⋅ L–1, with a lower detection limit of < 5 µg ⋅ L–1 as FFA.

PPCHEM® 2021, 23(2), 86–91

For Members only

IAPWS Fourth International Conference on Film Forming Substances (FFS2021) Highlights and Press Release

Barry Dooley

The IAPWS Fourth International Conference on Film Forming Substances (FFS2021) was held on the 23rd and 25th March 2021 as a virtual event chaired by Barry Dooley of Structural Integrity Associates. FFS2021 was a unique conference on a narrow topic in cycle chemistry control of power plants and steam generating facilities. In 2021 the conference attracted a record number of 130 participants from 28 countries which included 41 plant operators/users and 27 people from the Film Forming Substances chemical suppliers.

The FFS conferences are developed and supported by the International Association for the Properties of Water and Steam (IAPWS), and the FFS2021 was organized by PPCHEM AG, publisher of the PPCHEM® Journal. Three sponsors supported FFS2021: Trace Analysis, Fineamin Swiss Water-Treatment Chemicals and Swan Analytical Instruments.

PPCHEM® 2021, 23(2), 92–93