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About POWERGEN
POWERGEN is the premier networking and business hub for power generation professionals and solution providers. It unites power producers, utilities, EPCs, consultants, OEMs, and large-scale energy users. As the industry evolves toward cleaner and more sustainable energy, POWERGEN fosters a progressive environment for both established professionals and new energy leaders driving the transition to a more sustainable future.We invite technology experts, engineers, suppliers, decision-makers, and thought leaders to join us in exploring innovative solutions, learning from past and present projects, and shaping the future of power generation. This includes a focus on the total energy mix: powering the future, ensuring that all energy sources are considered in the journey towards sustainability.
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POWERGEN Updates
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04 Jun 202510:00 AM
(Sponsored)
With its bold red branding and signage, FPT Industrial has become a recognizable mainstay on the POWERGEN show floor.
As power demand surges and sustainability becomes non-negotiable, the company is adapting—and leading—on multiple fronts. In an recent interview, FPT Industrial North America executives discussed the evolution of the company’s power-gen engine lineup, shifting customer needs, and how the company is positioning itself amid a wave of decentralization and onsite resiliency strategies.
Watch the interview above.
The post FPT Industrial on innovation and resiliency in power generation appeared first on Power Engineering.
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21 May 202505:55 PM
The POWERGEN Call for Content deadline is June 2 2025, by 11:59 PM EST, which means you have less than two weeks to submit case studies and apply to speak at the conference. We are looking for case studies, technical insights and presentation proposals showcasing the latest in the power generation sector.
POWERGEN is being held January 20-22, 2026, at the Henry B. Gonzalez Convention Center in San Antonio, Texas.
Submit Content Here
Our conference tracks for 2026:
- Powering the Future
- Optimizing Plant Performance
- All About the Gas Turbine
- Nuclear’s Evolution
- Utility-Scale Renewables
- Energy Storage Deployments
- Onsite Power and Flexible Generation
- Hydrogen and Low-Carbon Fuels
- Carbon Capture and Emission Controls
- Exploring Trends in Hydropower
More on the tracks, with complete descriptions, can be found at the bottom of this page.
For Submitters:
The primary objective of our conference educational program is to spread industry knowledge and share the latest insights from the field. It is not to promote specific products, solutions or services. Overtly promotional or salesy pitches will be rejected. Our education is also largely targeted toward the end-use customer, such as a utility or independent power producer. The best submissions (and in the end, the best-attended) have an end-user as their speaker, or one of those speakers. Our committee of industry experts will factor end-use representation in deciding if a submission makes the POWERGEN program.
We have included three short videos on how to optimize your POWERGEN presentation pitch so it is most likely to be accepted by our advisory committee. The Call for Content ‘How-To” Series can be found on this page.
Don’t miss your chance to showcase the latest insights from the field, while sharing your knowledge and research with industry peers!
The post Less than 2 weeks to go: Submit case studies and apply to speak at POWERGEN 2026 appeared first on Power Engineering.
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13 May 202508:51 PM
By Brad Buecker, SAMCO Technologies and Buecker & Associates, LLC
Renewable energy has blossomed in recent years and will continue to do so. However, increasing electrical demand from AI data centers and many other users will require a balanced energy mix for decades to come. Dispatchable power to maintain grid stability is a critical factor in this regard. Simple- and combined-cycle power plants currently provide much of that power, along with remaining coal plants. Some mothballed nuclear reactors are being restarted, and nuclear power in general may enjoy a renaissance, possibly in the form of small modular reactors (SMR). Geothermal energy and underground hydrogen deposits have been highlighted in the news recently, and breakthroughs in fusion technology have some utilities looking at real-world applications within a decade or so. Most of these facilities require or will require high-purity makeup water, properly controlled and monitored boiler water/steam chemistry, well-conditioned cooling water, and modern wastewater treatment systems. These issues are also critical for steam generators and cogeneration systems at industrial plants, including pharmaceutical facilities, semiconductor manufacturers, steel mills, petrochemical plants; the list goes on and on.
In recognition of the continued major importance of water and steam treatment issues at power and industrial plants, I am pleased to report that the Electric Utility & Cogeneration Chemistry Workshop (formerly the Electric Utility Chemistry Workshop) will be co-locating the 43rd annual EUC2W with POWERGEN at the upcoming PGI conference in San Antonio in January 2026. This synergistic arrangement offers a great opportunity for energy plant managers and technical personnel to attend presentations from and network with water/steam experts. As I have learned from 40+ years of experience including two decades of direct plant work, even one major chemistry-related upset can potentially cost a company six- or seven figures in repairs and lost production. An initial failure is often indicative of conditions that will cause additional problems. Furthermore, some failures can jeopardize employee safety, which is the ultimate price.
Let’s now examine several of the current and most important issues facing plant personnel, and which remain critical topics at the EUC2W.
Not your father’s boilers
Much has changed since the early 1980s, when coal was still king. Some power plant personnel do not fully understand the nuances, both major and minor, of steam generation chemistry evolution. This problem is being exacerbated by the many retirements of “Baby Boomers,” who take their knowledge with them, leaving behind new personnel on a steep learning curve.
Well before coal-fired plants began to be retired due to environmental and economic issues, researchers and plant chemists started to recognize that once tried-and-true chemistry concepts had flaws. A prime example was the near universal belief, at least in the U.S., that any dissolved oxygen in boiler condensate/feedwater would cause severe corrosion. Thus, utility steam generators were always equipped with a feedwater mechanical deaerator for primary oxygen reduction, supplemented by chemical feed of a reducing agent such as hydrazine, with the goal of lowering the dissolved oxygen (D.O.) concentration to zero. In combination with aqueous ammonia injection for pH control, this feedwater chemistry program became known as all-volatile treatment reducing (AVT(R)). Beginning in 1986, with the failure of a feedwater line at a nuclear plant that killed four employees, research increasingly suggested that the reducing environment produced by AVT(R) chemistry induced flow-accelerated corrosion (FAC) in carbon steel feedwater piping, economizer elbows and other locations.1
Figure 1. Sudden feedwater piping failure from FAC.2 The high-pressure feedwater flashes to steam that can be injurious or lethal to any personnel in the vicinity. For utility boilers that have no copper alloys in the condensate/feedwater system, which includes virtually all combined cycle heat recovery steam generators (HRSGs), the recommended feedwater program now is all-volatile treatment oxidizing (AVT(O)), whose parent chemistry, oxygenated treatment (OT), was first developed for supercritical power units in Europe. AVT(O) requires dissolved oxygen (D.O.) in the feedwater, potentially up to 30 parts-per-billion (ppb), provided makeup water and condensate/feedwater are very pure (cation conductivity ≤0.2 µS/cm). Reducing agents/oxygen scavengers are eliminated, and units may operate with deaerator vents closed most of the time.3 Many HRSG operators around the world still do not seem to understand this concept, but they can find out much more about the science at the EUC2W. (One of the reference 3 authors is on the workshop planning committee.)
For non-utility applications, a question that periodically arises is, “Can AVT(O) be adopted in industrial steam generators?” The answer is usually no, because neither the makeup water nor condensate return meet the ≤0.2 µS/cm purity limit. The higher dissolved solids concentration and corresponding conductivity would induce significant oxygen corrosion. Furthermore, D.O. and chlorides synergistically enhance corrosion.
Another primary issue regarding HRSGs is that most units are of multi-pressure design, whose evaporator circuits are independent and require different treatment programs. Consider a common HRSG configuration, the triple-pressure, feed forward low-pressure (FFLP) design.
Figure 2. General schematic of a triple-pressure (FFLP) HRSG.2 The LP economizer and evaporator essentially serve as a feedwater heater for the IP and HP evaporators, which produce the turbine steam. The LP circuit is also the water source for the steam attemperators. Accordingly, traditional solid alkali (phosphate or caustic) boiler water treatment is not acceptable for LP circuit treatment, as it would introduce these chemicals directly to the steam system. Caustic in particular can quickly initiate stress corrosion cracking in turbine components. Solid alkalis are acceptable for the IP and HP evaporators, but the different pressures require different chemistry control ranges.4
Makeup water treatment – Reverse osmosis has become the workhorse
As power boiler technology progressed and boiler size/efficiency increased from the 1920s into the middle of the last century, the development of synthetic ion exchange resins greatly improved high-purity water production capabilities. While various IX system configurations emerged, the most popular design became:
Strong Acid Cation (SAC) → Strong Base Anion (SBA) → Mixed Bed
But even with relatively pristine surface water as the feed source, IX train run times may be limited to a few hours before regeneration is required. Short run times can influence operational flexibility, regeneration chemical costs, and personnel safety in handling dangerous chemicals. Beginning in the 1980s or thereabouts, water treatment experts began retrofitting reverse osmosis (RO) ahead of IX demineralizers. RO greatly extended IX resin run lengths and reduced chemical usage. Now, RO is often a standard item in power unit makeup treatment system design, with just a polishing IX unit for final treatment. RO is also becoming more popular as a replacement for sodium softening for industrial boiler makeup treatment.
Figure 3. A compact, skid-mounted RO. Source: SAMCO Technologies. What should not be done is purchase a unit, plug it in, and just let it run. Numerous impurities in raw water can cause fouling or scaling in spiral-wound RO membranes that in turn reduce output and eventually cause irreversible damage. Careful planning to ensure reliable operation is critical. Several of the most important items to select and protect RO units are:
- At project inception, begin collecting regular raw water samples to ascertain impurity concentrations and how they might change due to near-term (heavy storms) and seasonal influences.
- Suspended solids can quickly foul RO membranes, particularly the leading elements. Pretreatment particulate removal is a must. Standard in the last century was clarification/media filtration to remove suspended solids. The membrane technologies of micro- and ultrafiltration (MF and UF, respectively) have now become quite popular for particulate removal. Any choice requires careful evaluation based on raw water data to make the proper selection. For example, a heavy storm may stir up suspended solids in the raw water source that could potentially foul MF or UF membranes.
- As the membranes produce purified water (permeate) in a RO unit, the reject stream impurity concentration increases. So, of course, does the scaling potential. This aspect makes rigorous evaluation of raw water chemistry data quite important for selecting a proper scale inhibitor program.
- RO membranes are quickly degraded by oxidizing biocides, and especially chlorine, that may enter with the feed water. Accordingly, reducing agent injection or perhaps activated carbon filtration is necessary to remove the oxidizer. However, some microbes go into hibernation when they sense the biocide and then re-emerge once it is removed. RO cartridge filters and membranes offer splendid locations for organisms to settle and form slime masses that reduce performance and foul the membranes. Alternative oxidizing biocides or supplemental non-oxidizing compounds offer a solution to this difficulty.
- A well-designed RO has plenty of instrumentation for both physical (pressure, temperature, etc.) and chemistry (pH, conductivity, etc.) monitoring. A reputable RO manufacturer will provide what is known as a “normalization” program, which, when RO operating data is entered, will calculate system performance relative to “normal” or start-up conditions. These calculations are very important for scheduling membrane cleaning or troubleshooting off-spec performance. Importantly, temperature changes influence RO performance, and they sometimes can mask problems. A rule-of-thumb suggests cleaning when normalized performance drops by 10%.
These makeup water treatment issues and many others have been and continue to be presentation and discussion items at the workshop.
Cooling water treatment: A universal topic
Almost every industrial plant has one or more cooling systems. Corrosion, scaling, and especially microbiological fouling control are critical issues for maintaining cooling system reliability. Treatment chemistry for all three has undergone significant evolution over the last several decades, with some changes driven by environmental and safety issues. For example, prior to the 1980s, the primary corrosion and scale control method for open-recirculating systems (systems with a cooling tower(s) at the heart) consisted of sulfuric acid feed to lower the calcium carbonate scaling potential, combined with sodium dichromate feed to form a pseudo stainless-steel layer on carbon steel.
This treatment method was quite effective. However, the toxicity of hexavalent chromium led to a complete ban on the procedure. The replacement was inorganic and organic phosphate chemistry with supplemental polymers and perhaps a bit of zinc for additional scale and corrosion control. This chemistry was (is) considerably more complicated than acid/chromate. Water quality changes or other influences may cause serious scaling or conversely under-protected metal surfaces. Concerns have also arisen about the environmental impacts of cooling tower blowdown discharge, and its residual phosphate concentration, on receiving bodies of water. Phosphorus is a primary nutrient for algae.
Modern non-phosphate programs have emerged and are still evolving that utilize non-harmful organic compounds to form a protective mono-molecular layer on metal surfaces. The formulations include polymers for scale control. This chemistry has been a regular topic at recent workshops.5 So has the fact that these programs and their phosphate predecessors operate at a mildly basic pH level of around 8.0 or perhaps a bit above. The efficacy of chlorine as a biocide drops off rapidly as pH approaches 8. Alternatives such as bleach-generated bromine, chlorine dioxide, and monochloramine have gained popularity but require careful evaluation before being selected. The same goes for non-oxidizing biocides, which may be very effective but need rigorous review, and approval from environmental regulators, to be applied safely and cost-effectively.
Conclusion
This article highlighted some, but not nearly all, of the important issues that regularly appear on the agenda of the EUC2W. They also make up many of the networking discussions at the workshop. For all Power Engineering readers who must deal with these issues, I invite you to come join us at POWERGEN 2026. Then, plan to stay for the remainder of the conference. Besides the technical papers, the exhibit hall presentations on current and new power generation technologies are outstanding and highly informative. And, of course, reputable technology providers have booths throughout the exhibit floor to answer questions about modern solutions to a multitude of energy issues.
References
- Guidelines for Control of Flow-Accelerated Corrosion in Fossil and Combined Cycle Power Plants, EPRI Technical Report 3002011569, the Electric Power Research Institute, Palo Alto, California, 2017. This document is available to the industry as a free report because FAC is such an important safety issue.
- Buecker, B., Shulder, S., and Sieben, A., “Fossil Power Plant Cycle Chemistry”; pre-workshop seminar for the 39th Annual Electric Utility Chemistry Workshop, June 4, 2019, Champaign, Illinois.
- Smith, J.B., and Craven, D.M., “Supplemental Oxygen for All-Volatile Treatment under Oxidizing Conditions”; PPCHEM Journal, 26/2024 – No. 6, November/December 2024.
- International Association for the Properties of Water and Steam, Technical Guidance Document: Phosphate and NaOH treatments for the steam-water circuits of drum boilers of fossil and combined cycle/HRSG power plants (2015).
- Post, R., Buecker, B., and Shulder, S., “Power Plant Cooling Water Fundamentals”; pre-workshop seminar for the 37th Annual Electric Utility Chemistry Workshop, June 6, 2017, Champaign, Illinois.
About the Author: Brad Buecker currently serves as Senior Technical Consultant with SAMCO Technologies. He is also the owner of Buecker & Associates, LLC, which provides independent technical writing/marketing services. Buecker has many years of experience in or supporting the power industry, much of it in steam generation chemistry, water treatment, air quality control, and results engineering positions with City Water, Light & Power (Springfield, Illinois) and Kansas City Power & Light Company’s (now Evergy) La Cygne, Kansas, station. Additionally, his background includes eleven years with two engineering firms, Burns & McDonnell and Kiewit, and he spent two years as acting water/wastewater supervisor at a chemical plant. Buecker has a B.S. in chemistry from Iowa State University with additional course work in fluid mechanics, energy and materials balances, and advanced inorganic chemistry. He has authored or co-authored over 300 articles for various technical trade magazines, and he has written three books on power plant chemistry and air pollution control. He is a member of the ACS, AIChE, AIST, ASME, AWT, CTI, and he is active with Power-Gen International, the Electric Utility & Cogeneration Chemistry Workshop, and the International Water Conference. He can be reached at bueckerb@samcotechnologies.com and beakertoo@aol.com.
The post POWERGEN welcomes the Electric Utility & Cogen Chemistry Workshop for 2026 appeared first on Power Engineering.
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14 Apr 202507:27 PM
Calling all utilities, independent power producers, EPCs, large-scale energy users and more…
POWERGEN 2026 has opened our ‘Call for Content,’ which means we are officially looking for thought leaders and presenters to join our speaker lineup. Send us your case studies and technical abstracts today and join the top conference educational program in electric power generation!
POWERGEN is being held January 20-22, 2026, at the Henry B. Gonzalez Convention Center in San Antonio, Texas.
We are excited to announce the new conference tracks for 2026:
- Powering the Future
- Optimizing Plant Performance
- All About the Gas Turbine
- Nuclear’s Evolution
- Utility-Scale Renewables
- Energy Storage Deployments
- Onsite Power and Flexible Generation
- Hydrogen and Low-Carbon Fuels
- Carbon Capture and Emission Controls
- Exploring Trends in Hydropower
Of note:
Powering the Future will feature big-picture discussions on how the power sector can confront the issues of decarbonization, reliability and affordability. This includes topics like utility planning and load growth, navigating supply chain constraints, and adapting to evolving policy and regulations.
Onsite Power and Flexible Generation is an updated version of our microgrids track and highlights the energy strategies customers like data centers, hospitals, universities and industrials are increasingly deploying in response to grid constraints and for reliability.
Hydrogen and Low-Carbon Fuels explores the alternative fuels of power generation, to more nascent technologies like hydrogen and ammonia to the more mature options like biofuels.
More on the tracks, with complete descriptions, can be found at the bottom of this page.
For Submitters:
The primary objective of our conference educational program is to spread industry knowledge and share the latest insights from the field. It is not to promote specific products, solutions or services. Overtly promotional or salesy pitches will be rejected. Our education is also largely targeted toward the end-use customer, such as a utility or independent power producer. The best submissions (and in the end, the best-attended) have an end-user as their speaker, or one of those speakers. Our committee of industry experts will factor end-use representation in deciding if a submission makes the POWERGEN program.
We have included three short videos on how to optimize your POWERGEN presentation pitch so it is most likely to be accepted by our advisory committee. The Call for Content ‘How-To” Series can be found on this page.
Session submissions are due on June 2 2025, by 11:59 PM EST. Late submissions will not be accepted, no exceptions. All submitters will be notified of their acceptance status by early September 2025.
Don’t miss your chance to showcase the latest insights from the field, while sharing your knowledge and research with industry peers!
The post We are LIVE: Submit case studies and apply to speak at POWERGEN 2026 appeared first on Power Engineering.
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07 Apr 202506:49 PM
By Brad Buecker, SAMCO Technologies
Introduction
Renewable resources now provide a significant portion of U.S. electricity needs. However, issues related to renewable energy storage capacity, a projected large nationwide load increase (much of it due to data center growth), grid stability, political influences, and others will continue to require traditional power generation. Some utilities are delaying the decommissioning of remaining coal plants, but new simple- and combined cycle power generating units are expected to fill much of the need for dispatchable generation. Additionally, support for small modular nuclear reactors appears to be gaining momentum. While no crystal ball exists to calculate the exact pathway of these developments, it is apparent that high-purity makeup water production will remain a critical process for much of the power generation industry. And, of course, purified makeup is required for many other industries including cogeneration, semi-conductor, pharmaceutical, the list goes on and on.
Kevin Clark and his POWERGEN staff recognize the importance of these issues and are working to reintegrate water/steam treatment topics into the conference. At POWERGEN 2025, he offered a an O&M Knowledge Hub slot for a colleague and me to discuss modern makeup water treatment methods for combined cycle heat recovery steam generators (HRSGs) and cogeneration units.1 The positive response to our presentation signaled that a significant group of POWERGEN attendees recognized the importance of well-controlled HRSG water/steam chemistry. Outages from chemistry-induced failures can be enormously expensive and, in some cases, threaten employee safety. This two-part series highlights a number of important topics from the presentation, and it provides additional insights regarding modern makeup water treatment methods.
Makeup Water Parameters
High-pressure steam generators for power production require makeup water with low part-per-billion (ppb) concentrations of impurities. A common makeup water treatment effluent guideline is shown below.
To understand how this purity may be obtained, let us briefly examine the evolution of treatment technology over the decades, in a discussion that also offers practical information for those Power Engineering readers at co-generation and industrial steam plants
As power boiler technology progressed and boiler size/efficiency increased from the 1920s into the middle of the last century,2 the development of synthetic ion exchange resins greatly improved high-purity water production capabilities.
Figure 1. Closeup photo of ion exchange resin beads. This Photo by Unknown Author is licensed under CC BY-SA. One of the first applications (which continues to this day) of ion exchange was basic sodium softening for lower-pressure steam generators, as these units can tolerate moderate concentrations of most dissolved ions, apart from the hardness ions, calcium and magnesium. Figure 2 below is an extract taken from the recent revision of the American Society of Mechanical Engineers (ASME) industrial boiler water guidelines.3 (The complete guidelines are available from the ASME at very reasonable cost and should be in the library of any industrial plant with steam generators.)
Figure 2. Data extracted from Table 1, Reference 3 – “Suggested Water Chemistry Targets Industrial Water Tube with Superheater.” Note the very low feedwater hardness limits for all cases. The most common backbone for ion exchange resins is polystyrene cross-linked with divinylbenzene. The typical active group is the sulfonate molecule (SO3–). Figure 3 outlines the basic structure of softener resin, where, in this case, each active site contains an exchangeable sodium ion. Just one resin bead may have up to 4 x 1019 active sites.4
Figure 3. Basic schematic of the IX molecular structure showing cross-linkage of polystyrene with divinylbenzene along with active sites containing sodium ions. The fundamental exchange chemistry is:
Figure 4. Basic softener reactions. The “R” in R-SO3-Na+ symbolizes the organic backbone of the resin beads. Note the equilibrium reaction arrows that indicate greater attraction (affinity) of the dissolved ions, and especially the divalent cations, Ca2+, Mg2+, to the resin over sodium. As a softener processes water, the resin accumulates hardness and other cations until reaching exhaustion. The standard procedure is to take the unit out of service, followed by backwash and then regeneration with a brine solution. The concentrated brine drives the exchange reaction in the opposite direction to restore most of the resin capacity for the next run.
Figure 5. Multiple softener vessels with feed/backwash piping that provide redundancy for softened water production. A modern sodium softening configuration is shown in Figure 5.
Sodium softening is still very common for lower-pressure (≤600 psi) industrial steam generators. Systems frequently include a downstream forced draft decarbonator or dealkalizing unit to remove bicarbonate alkalinity (HCO3-), which otherwise can decompose to carbon dioxide in the boiler and carry over with steam. The CO2 will then dissolve in condensate to lower the pH and induce corrosion of carbon steel condensate return piping.
It has been this author’s direct experience, combined with accounts from numerous water treatment colleagues, that industrial plant personnel too often focus on process engineering and chemistry to the neglect of softener operation and maintenance. This oversight leads to hardness carryover and scale formation in boilers, with tube failures a frequent outcome.
Figure 6. Boiler tube bulges and blisters caused by internal scale formation and overheating.5 With this background information in place, we will now examine makeup treatment developments for high-pressure utility steam generators.
High-Pressure Makeup Treatment
In the middle of the last century, ion exchange became the “go-to” process for producing high-purity makeup. While various IX system configurations emerged, the most popular design became:
Strong Acid Cation (SAC) –> Strong Base Anion (SBA) –> Mixed Bed
Figure 7 outlines the basic structure of SAC resin. The reader will note the same organic backbone as sodium softening resins, but with hydrogen ions (H+) replacing sodium ions at the active sites
Figure 7. Basic schematic of SAC resin. Cations exchange with hydrogen ions. The mildly acidified effluent flows to the SBA vessel, in which (the somewhat more complex) active groups hold hydroxide ions (OH–). Here, the anionic impurities are exchanged. The final net reaction is:
H+ + OH– –> H2O (1)
This basic two-step process can remove most dissolved mineral ions from the feed:
However, SAC/SBA alone cannot produce water of the purity shown in Table 1, so a mixed-bed polisher became standard for many systems. As the name implies, the MB vessel contains intermingled SAC and SBA resins.
As with sodium softeners, typical for these early units (and some remaining systems today) was on-site regeneration. Common regenerant concentrations are:
· SAC: Concentrated sulfuric acid (93%-98%) diluted to 4%. Sometimes a multistage regeneration process, starting off at say 2% acid concentration, may be needed to prevent calcium sulfate (CaSO4) precipitation in the resin.
· SBA: Concentrated sodium hydroxide (50%) diluted to 4%.
Regeneration is usually performed within the ion exchange vessel, where accurate regenerant concentration and flow rate measurements are necessary to expose the resins to the required regenerant mass. (A typical specification has units of lb/ft3 or metric equivalents.) One major design improvement was evolution from co-current to counter-current regeneration, which significantly improved the efficiency of the process. Space limitations prevent an in-depth discussion, but details are available in Reference 6. This reference also discusses mixed-bed regeneration, where the density difference between cation and anion resins induces, via water sluicing, resin separation, whereupon each can be regenerated and then remixed.
As suggested above, ion exchange was a marvelous advancement for producing the makeup required for high-pressure steam generators. However, even with relatively pristine waters as the feed source, IX train run times may be limited to a few hours before regeneration is required. Short run times can be problematic with regard to operational flexibility, regeneration chemical costs, and personnel safety in handling dangerous chemicals. (Properly located and well-maintained safety shower stations and other safety equipment are top priority.) The maturation of membrane technologies, and especially reverse osmosis (RO), have greatly changed the landscape of makeup water treatment, as we will now review.
Reverse Osmosis to the Rescue
As RO technology evolved and matured through the middle and end of the last century, water treatment experts realized that retrofitting a reverse osmosis unit ahead of an IX demineralizer could greatly extend IX resin run lengths and reduce chemical usage.
Most modern RO systems are of the spiral-wound design in which the membrane along with spacer sheets are wrapped around a perforated core. Each assembly is known as an “element”.
Figure 8. Cutaway view of an RO element. Common element dimensions are 8” in diameter by 40” in length. The surface area of a single membrane has increased from an original 365 ft2 design to 400 ft2 or even greater. Multiple elements (typically five or six per pressure vessel) are assembled in series, with multiple pressure vessels needed for normal industrial applications.
Figure 9. A compact, skid-mounted RO. Source: SAMCO Technologies. Feed enters the front end of each element and passes along the feedwater carrier, where the feed pressure forces water through the membrane. This process is known as crossflow filtration. The purified water (permeate) flows to the central core, while the increasingly concentrated feedwater (known as concentrate or reject) exits the element. Brine seals prevent feedwater from short-circuiting the elements, and anti-telescoping devices inhibit the water pressure from pushing the membrane and spacer sheets out of the element.
A key aspect of crossflow filtration is that the reject impurity concentration continually increases as the feed passes along the elements. This concentration increase has a large influence on membrane performance and selection of scale control chemistry, as will be discussed in Part 2.
A fundamental, single-pass RO configuration is shown below.
Figure 10. Schematic of a single-pass, two-stage RO unit, where the first stage reject is treated in a second stage. The second stage reject goes to waste. For normal surface and ground waters, each stage will produce approximately 50% purified water (permeate) and 50% reject. Thus, the overall feed-to-permeate conversion of a standard two-stage RO is 75%. Just half the membranes are needed for the second stage as for the first stage.
Modern RO membranes can remove over 99% of dissolved ions. Membrane flux rate (gallons per square foot per day or metric equivalents) is a critical design factor for the number of membranes and pressure vessels required per application. Flux rates are influenced by feed water chemistry. Reference 7 offers additional details.
For high-pressure steam generators and other high-purity water applications, the two-pass RO design shown below is common.
Figure 11. A basic two-pass RO schematic, where each pass has two stages. In the two-pass configuration, the permeate from the first pass is further treated in the second pass to produce water of even greater purity. Note that the second-pass reject is of high enough quality that it can be recycled to the RO inlet rather than discharged to waste. Also note the (typically small) caustic feed to the first pass permeate stream. Caustic will convert any free CO2 in the permeate to bicarbonate alkalinity, which is then removed in the second pass.
At many coal-fired power plants in the 1980s and 1990s, including both of this author’s former plants, management installed RO ahead of existing demineralizers. But now, as combined cycle power generation has replaced coal, membrane technologies are frequently included in the makeup system design phase, with ion exchange serving in a polishing role. Figure 12 outlines a fundamental configuration.
Figure 12. A now common makeup design for combined cycle power plants, with micro- or ultrafiltration for upstream suspended solids removal, RO, and portable mixed-bed “bottles” for RO permeate polishing, where an outside contractor regularly swaps out an exhausted bottle and regenerates the resin off-site. Less common but popular at some facilities is electrodeionization (EDI) for polishing. Look for additional discussion on EDI in a future article. Critical for reliable operation of RO units is well-designed and operated pre-treatment, with conscientious monitoring of process chemistry and physical parameters. We will explore these issues in Part 2, along with the often overlooked need of having comprehensive raw water chemistry data as the backbone of makeup system design.
Conclusion
This article and the upcoming second part of the series serve as a follow-up to a well-received POWERGEN 2025 O&M Knowledge Hub presentation. POWERGEN 2026 (January 20-22, 2026, San Antonio, Texas) promises to expand the discussion of steam generation, cooling water, and makeup water treatment technologies. Many new personnel are being exposed to these issues and need good sources of information to reliably operate their plants.
Disclaimer
This article offers general information and should not serve as a design specification. Every project has unique aspects that must be individually evaluated by experts from reputable water treatment and engineering firms. Also, any issues that could potentially have an environmental influence, for example, wastewater discharge from a proposed makeup, process, or cooling water treatment system, must be presented to and approved by the proper environmental regulators during the project design phase.
References
1. Buecker, B., and E. Sylvester, “Modern Makeup Water Treatment Methods for Combined Cycle, Co-Gen, and Other Energy Industries”; O&M Knowledge Hub, POWERGEN25, February 12, 2025, Dallas, Texas.
2. Kitto, J.B., and S.C. Stultz, eds., Steam/its generation and use. 41st edition, The Babcock & Wilcox Company, Barberton, Ohio, 2005.
3. Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers, The American Society of Mechanical Engineers, New York, NY, 2021.
4. Personal conversations with Ed Sylvester, ChemTreat.
5. S. Shulder and B. Buecker, “Combined Cycle and Co-Generation Water/Steam Chemistry Control”; pre-workshop seminar to the 40th Annual Electric Utility Chemistry Workshop, June 7-9, 2022, Champaign, Illinois.
6. D. Owens, Practical Principles of Ion Exchange Water Treatment, Tall Oaks Publishing, Littleton, Colorado, 1995.
7. W. Byrne, Reverse Osmosis: A Practical Guide for Industrial Users, Tall Oaks Publishing, Littleton, Colorado, 2002.
About the Author: Brad Buecker currently serves as Senior Technical Consultant with SAMCO Technologies. He is also the owner of Buecker & Associates, LLC, which provides independent technical writing/marketing services. Buecker has many years of experience in or supporting the power industry, much of it in steam generation chemistry, water treatment, air quality control, and results engineering positions with City Water, Light & Power (Springfield, Illinois) and Kansas City Power & Light Company’s (now Evergy) La Cygne, Kansas, station. Additionally, his background includes eleven years with two engineering firms, Burns & McDonnell and Kiewit, and he spent two years as acting water/wastewater supervisor at a chemical plant. Buecker has a B.S. in chemistry from Iowa State University with additional course work in fluid mechanics, energy and materials balances, and advanced inorganic chemistry. He has authored or co-authored over 300 articles for various technical trade magazines, and he has written three books on power plant chemistry and air pollution control. He is a member of the ACS, AIChE, AIST, ASME, AWT, CTI, and he is active with Power-Gen International and the International Water Conference. He can be reached at bueckerb@samcotechnologies.com and beakertoo@aol.com.
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