Author: anderthalbAdmin

Corrosion Product Monitoring – Key Parameters to Achieve High Accuracy and Reliable Analysis

Niken Wijaya 

Efforts have been made at AGL’s Liddell Power Station, Australia, to determine the best corrosion product monitoring practices in order to establish baseline data that are reliable and accurate. This effort is an outcome of the decision made to apply a film forming product (FFP) at Liddell Power Station, with the goal of minimising corrosion product transport from the boiler feed system to the boiler on all four units until its scheduled closure in 2022. Despite guidelines and studies done on this subject, there are still many knowledge gaps that need to be addressed. This paper aims to evaluate the accuracy of onsite ferrozine and porphyrin analyses for iron and copper analysis and how they compare to external analyses by inductively coupled plasma mass spectroscopy with an octupole reaction cell. This paper also investigates the influence of several key parameters on corrosion product monitoring including the use of an integrated corrosion product sampler, the use of smaller pore filter paper, the forms of corrosion products in the system, and the use of cation paper, which are critical in establishing the best practices for corrosion product monitoring. Liddell’s baseline data on corrosion product were used to evaluate the efficiency of the current cycle chemistry program and to verify the need for FFP dosing for corrosion protection.

PPCHEM^® 2020, 22(6), 230–250

The Challenges of Industrial Boiler Water Treatment

Brad Buecker and Tim Hughes

High-pressure steam generators for power production require high-purity makeup and feedwater and controlled boiler water chemistry to minimize corrosion and scale formation in the boilers, superheater/reheater circuits, and turbines. Numerous articles in the PPCHEM® journal over the last two decades have outlined these chemistries and their evolution.
However, while many heavy industries have high-pressure steam generators for cogeneration needs, these plants and many other smaller facilities also have low-pressure boilers that produce process steam. The lower heat fluxes and pressures in these steam generators somewhat alleviate the stringent treatment requirements necessary for highpressure units but offer more complexity in the choice of optimum treatment methods.
This article provides an overview of modern methods for protecting lower-pressure steam generators from factors that typically do not plague their high-pressure counterparts.

PPCHEM^® 2020, 22(6), 252–259

Heat Transfer Add-on to the UNB-CNER CANDU-6 PHT System Material Transport Model

Olga Y. Palazhchenko, William G. Cook, Alex L. Martin, and Dean C. Taylor

Reduced heat transfer in steam generators has safety consequences such as the risk of fuel dryout due to increasing reactor inlet header temperature (RIHT). To maintain the RIHT within the safe operating envelope, it is necessary to model factors that contribute to its rise, including chemical processes such as corrosion product transport and deposition and mechanical effects such as component degradation.
In the recent add-on to the UNB-CNER PHT Corrosion Product and Activity Transport Code, a combination of heat transfer mechanisms, updated thermodynamic equations for the properties D₂O and H₂O, station data, and the existing model capability of predicting primary-side material transport are used to create and optimize a one-dimensional simulation of a typical CANDU-6 boiler. Data from Point Lepreau Nuclear Generating Station is used to benchmark various model parameters, allowing for predictive simulations, where RIHT trends can be forecasted into the future using desired outage and boiler cleaning schedules.

PPCHEM^® 2020, 22(6), 262–273

Film Forming Corrosion Inhibitor with Improved Handling, Feeding, and Corrosion Control Properties for Steam Generators

Mahesh Budhathoki, Donald Meskers Jr., Claudia Pierce, and Gregory Robinson

Film forming amine (FFA) products containing octadecylamine (ODA) or oleyl propylenediamine (OLDA) are known to provide excellent corrosion protection to the alloys used in the steam-water cycle of power plants. However, product formulations based on these filming amines exhibit poor water solubility, which often hinders successful application due to formulation stability, feeding, and handling. In this work, the water solubility of an OLDA-based FFA product is significantly improved with the addition of a co-surfactant and its efficacy as a corrosion inhibitor in steam generators is evaluated. Research boiler experiments indicate that the vapor-liquid distribution ratio of OLDA decreases by enhancing its water solubility. Also, the conductivity after cation exchange (CACE) measured in steam suggests that under normal boiler operation conditions, unlike neutralizing amines or co-solvents, the added co-surfactant does not contribute to the CACE in steam. Furthermore, electrochemical and corrosion testing indicates that the water-soluble FFA product can effectively inhibit corrosion, which is attributed to its ability to form a hydrophobic film on metal surfaces, as suggested by the contact angle measurements.

PPCHEM^® 2020, 22(5), 182–194

Testing the Suitability of the AMI CACE Monitor for the Water-Steam Cycle at Lippendorf Power Plant

Karla Georgi-Kruggel

In the period from January 06, 2020, to June 30, 2020, an analyzer for the automatic and continuous determination of conductivity before and after a cation exchanger with electro-deionization was tested at the Lippendorf Power Plant of Lausitz Energie Kraftwerke AG, Germany.

This report describes the setup and outcome of the trial. In summary, the proof of suitability of the analyzer for the monitoring of the water-steam cycle and the control of the conditioning agent quantities was positively demonstrated for all tested measuring points.

PPCHEM^® 2020, 22(5), 196–202

Comparative Study on the Ion Exchange Removal of Gadolinium Nitrate under the Conditions of the Moderator System of a Nuclear Reactor Using Styrene- and Acrylic- Acid-Based Macroporous Weak Base Anion Resins

A. L. Rufus, Padma S. Kumar, C. S. Sanjana, and S. Velmurugan

The fission reaction in a nuclear reactor is regulated by adding “neutron poison” to the system. Gadolinium has a high neutron absorption cross section and hence is used for this purpose in the form of aqueous solution of gadolinium nitrate. After its intended use, the neutron poison is removed from the system using mixed-bed (MB) ion exchange resin columns. A comparative study between the styrene- and acrylic-acid-based macroporous weak base anion (MWBA) resins in the MB column was carried out. Based on the parameters evaluated, which include (i) extent of utilization of the ion exchange capacity, (ii) precipitation of gadolinium in the ion exchange column, (iii) pressure drop across the column and (iv) radiation stability, the use of acrylic-acid-based resin in the MB ion exchange column was found to be good. The ion exchange capacity for acrylic-acid-based MWBA resin was higher (2.6 mEq ∙ mL^–1 of resin as against 2.0 mEq ∙ mL^–1 for styrene-based MWBA resin), 65 % utilization capacity as against 50 % for styrene-based MWBA resin, less precipitation of gadolinium (0.001 % as against 0.004 %), a favorable pressure drop and better retention of ion exchange capacity on irradiation.

PPCHEM^® 2020, 22(5), 204–213