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Report on the Power Cycle Instrumentation Seminar (PCIS) Germany 2025

Tapio Werder

For the second time, the Power Cycle Instrumentation Seminar (PCIS) series made a stop in Germany. The PCIS Germany 2025 in Aachen was held under the patronage of PPCHEM AG, with financial sponsorship from SWAN Analytical Instruments and REICON Wärmetechnik und Wasserchemie Leipzig GmbH.

The PCIS series focuses on the analytical methods, the sampling points, and the critical issues for each parameter. The emphasis lies on spreading knowledge of cycle chemistry and an understanding of analytical instruments. The seminar provides a well-proven mixture of theoretical background information on cycle chemistry, sampling, and monitoring as well as a deeper look into analytical methods and critical issues for each parameter, concerning operation, verification, and calibration. This report summarizes the two days of the PCIS Germany 2025.

PPCHEM® 2025, 27(2), 68–71

Pre-Stripper Sulfite-Induced Coal Fly Ash Leaching – Part 2: Leaching of Iron and Other Transition Metals as Monitored by Inductively Coupled Plasma Mass Spectrometry

Emmanuel K. Quagraine, Nikki Wirtz, Cedric Huang, and Dwayne Selensky

This is Part 2 of a series of investigations on understanding the impact SO₂ in flue gas (FG) has on an integrated amine solvent based sulfur dioxide (SO₂) and carbon dioxide (CO₂) capturing process such as practiced at the Boundary Dam Unit 3 carbon capture and storage plant. It follows the Part 1 article on the effect of SO₂ on coal fly ash (CFA) leaching of iron and extends it to other transition metals (TMs) that may potentially cause oxidative degradation of amines used in the process. The results confirm the findings in Part 1 that, apart from pH on its own, SO₂ and its pH-speciated aqueous forms affect the leaching of TMs and potentially catalyze degradation of amines used to capture acidic contaminants from post-combustion FG. The sulfite-induced leaching of TMs occurred primarily under acidic conditions that simulate pre-scrubber and amine-based SO₂ capture conditions (pH ≤ 6). This occurred either exclusively (e.g., for iron) under acidic conditions, or additionally also in alkaline solutions – substantially for copper when at 50 °C, but only moderately for vanadium and titanium (and copper when at 90 °C). The alkaline leachates that represent conditions of the post-combustion CO₂ capture process are as follows for a caustic chimney tray fly ash (CCTF) sample: copper (Cu) > iron (Fe) > vanadium (V) > titanium (Ti) > nickel (Ni) > chromium (Cr) > manganese (Mn); and for a flue gas cooler inlet fly ash (FGCIF) sample: V > Fe > Mn > Ti > Cu > Ni > Cr. However, TMs leached more under the acidic conditions (pH 4 to 6) that better represent the SO₂ capture process, and the leaching order is as follows for CCTF: Fe > Cu > V > Ti > Mn > Cr > Ni; and for FGCIF: Fe > Mn > Ti > V > Ni > Cu > Cr.

PPCHEM® 2025, 27(2), 74–91

Highlights and Press Release Annual Meeting and Conference in Bochum, Germany

GSAPWS e.V.

The German-Swiss Association for the Properties of Water and Steam (GSAPWS) e.V. held its annual general meeting and conference on March 6 and 7, 2025. This year, the events took place at Ruhr University Bochum.

PPCHEM® 2025, 27(2), 94–95

Novel Prediction Model Based on the Two-Film Theory for the Ammonia Distribution Coefficient in Heat Recovery Steam Generators of Gas Turbine Combined Cycle Power Plants

Yuta Nakatsuchi, Haruka Kido, Akihiro Hamasaki, and Shinji Fujimoto

In a combined cycle power plant with a heat recovery steam generator, ammonia and hydrazine are injected into the boiler feedwater, while sodium phosphate is used in the drum boiler water. However, hydrazine is suspected to cause health problems, and sodium phosphate may cause phosphoric acid corrosion. An alternative method has been applied in recent years wherein only ammonia is used for water treatment. Although the ammonia concentration in the drum boiler water depends on the gas-liquid distribution coefficient of ammonia, the measured result of the gas-liquid distribution coefficient in the actual plants is found to be smaller than the reported value in the equilibrium state. This is because the boiler feedwater passes through the drum boiler before attaining equilibrium. In this study, a novel dynamic model for the gas-liquid distribution of ammonia between the drum boiler water and the drum boiler steam was investigated by applying the two-film theory. Using this novel model, the ammonia gas-liquid distribution coefficient in the drum boiler can be estimated more accurately. Furthermore, the ammonia concentration of the boiler feedwater can be determined, even in a water treatment system with only ammonia, which is effective in preventing flow-accelerated corrosion of the drum boiler.

PPCHEM® 2025, 27(2), 102–112

Erratum

Nobody is perfect and everybody makes mistakes sometimes. We apologize to the authors and to our readers for the mistakes in this article:

PPCHEM® 2025, 27(2), 73

Cooling Tower Operating and Water Treatment Fundamentals – Part 4

Brad Buecker

Cooling towers and cooling water systems are an integral feature of many power plants and thousands of industrial facilities. The previous installments of this series focused on microbiological fouling and corrosion issues, as these mechanisms can cause severe problems. But by their very nature, cooling towers, in which water evaporation is the primary heat transfer method, cause an increase in concentration of both dissolved and suspended solids. Deposition and scaling can become quite problematic without careful chemistry control. This installment examines scale-forming mechanisms. In Part 5, we will examine modern corrosion/scale control chemistry. Some chemical inhibitors serve a dual function.

PPCHEM® 2025, 27(1), 4–8

Pre-Stripper Sulfite-Induced Coal Fly Ash Leaching – Part 1: Leaching of Iron(II) and Iron(III) as Monitored by Spectrophotometry

Emmanuel K. Quagraine, Nikki Wirtz, and Dwayne Selensky

Iron (Fe) is known to catalyze oxidative degradation of amines in the post combustion CO₂ capture (PCCC) process. However, sources of Fe for such degradations are poorly characterized. One aspect of the PCCC process which is poorly researched is the interaction of sulfur dioxide (SO₂) gas in the flue gas (FG) with coal fly ash (CFA) and how this can affect amine degradation. Understanding that the SO₂ would be dominantly present in the anionic pH speciated forms (bisulfite (HSO₃^–_(aq)) and sulfite (SO₃^2–_(aq))) as a result of caustic scrubbing or amine-based desulfurization and that ammonia is commonly present either in original FG or as an amine degradation product, CFA leaching of Fe by ammonium sulfite ((NH₄)₂SO₃) was experimentally examined under different pH (~ 4 to 10) and temperature (50 °C to 90 °C) conditions to simulate various pre-stripper sections within an amine solvent based SO₂ and carbon dioxide (CO₂) capturing process such as at the Boundary Dam Unit 3 carbon capture and storage (BD3 CCS) facility. The results suggest that SO₂ and its pH-speciated aqueous forms can leach Fe, and thereby catalyze oxidative degradation of common amines used in capturing acidic contaminants from post-combustion FG. With the addition of (NH₄)₂SO₃ (0.25 mol ⋅ L^–1), the effect of SO₃^2– on the leaching of iron(III) (Fe³⁺) and iron(II) (Fe²⁺) was apparent and distinctly different from the effect of pH per se. Thus, irrespective of the amine type, SO₂ and its pH speciated forms can generate Fe ions to catalyze the degradation. Still, SO₃^2–-induced Fe leaching occurred more dominantly in acidic solutions that simulate the pre-scrubber and amine-based SO₂ capture conditions (pH ≤ 6) and less in alkaline aqueous conditions simulating amine-based CO₂ capture (i.e., pH of ~ 8 to 10). The work does not seem to support an effect of SO₂ on CFA leaching of Fe under prestripper conditions as the principal factor in catalyzing oxidative degradation of amines used in CO₂ capture, even though the association with pH depression could still make it significant. At pH = 8, the total leached Fe ions averaged only ≤ 0.2 mg ⋅ L^–1 and ≤ 1.0 mg ⋅ L^–1 from CFA obtained from flue gas cooler inlet and the caustic polisher in the SO₂ loop, respectively. Yet, in an integrated amine solvent SO₂ and CO₂ capturing process as employed at BD3 CCS, the effect is expected to be more significant with respect to amine degradation within the SO₂ capture process.

PPCHEM® 2025, 27(1), 14–32

ABHUG2024 Highlights and Press Release

The annual meeting of ABHUG held on the 3rd to 5th December 2024 in Brisbane, Australia was chaired by Barry Dooley of Structural Integrity Associates, UK and Bob Anderson, Competitive Power Resources, USA. This ABHUG conference included conventional fossil boiler technology and issues closely related to those in HRSGs. ABHUG2024 attracted 90 participants from Australia, New Zealand, UK and USA. About 45 % of the participants were Users. The next meeting of ABHUG will be in Brisbane in November 2025.

PPCHEM® 2025, 27(1), 34–35

How to Analyze Film-Forming Amines – Analytical Methods and Best Practices

Ronny Wagner

Film-forming amines (FFAs) are increasingly being used instead of conventional conditioning chemicals, as they offer advantages in corrosion protection, especially during operational shutdowns. This article offers an examination of the analytical methods used for quantifying FFAs, highlighting their theoretical basis, practical applications, and inherent challenges. It addresses sampling protocols and monitoring techniques to ensure optimal performance and compatibility within diverse systems. The goal is to provide a comprehensive technical resource for researchers and practitioners aiming to enhance the efficacy of FFAs in industrial applications.

PPCHEM® 2025, 27(1), 38–42

2024’s Scientific and Technical Contributions

PPCHEM® 2025, 27(1), 48–56