Centerbrook, CT, United States
Centerbrook, CT, United States

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Bennett D.C.,Corrosion Probe Inc
PEERS Conference 2014 | Year: 2014

1. Devising & methodically implementing a workable, multi-outage approach 2. Setting condition-based coating priorities - protection trumps pretty! 3. Only painting as much area as can be properly prepared and coated in the available time (Do not paint paint!) 4. Use qualified procedures to properly apply the "right" coating. 5. Use proven solutions to protect non-paintable surfaces. 6. Monitor coating performance - for continuous improvement.


Nixon R.A.,Corrosion Probe Inc
Journal of Protective Coatings and Linings | Year: 2012

A special report on the basics of maintaining and protecting concrete with high performance coatings is discussed. First of all, the engineer should be certain there is a clear understanding of the damage mechanisms that caused the concrete to deteriorate. Testing must be performed to determine the concentration of those ions and how deeply they have penetrated. As with protective coatings adhesion, adequate concrete surface profile, degree of cleanliness, and removal of contaminants are critical to optimizing the adhesion of concrete repair materials to existing concrete substrates. It is essential that substrate contaminants like chlorides and sulfates are removed to acceptable levels to prevent further rebar corrosion or expansive sulfate reactions. If there is a through-crack in the substrate that could manifest structural movement in the future, it must be treated like a moving joint. When making concrete repairs with a radius at inside or outside corners in structures, repairs should be made with a radius that avoids 90 degree transitions.


Maley R.,Corrosion Probe Inc
Journal of Protective Coatings and Linings | Year: 2014

The article examines many of the common errors that often occur when concrete substrates are rehabilitated and offers practical solutions for prevention of said errors. The practice of lining concrete substrates has increased exponentially over the last 30 years. Environmental regulations, coupled with changes to treatment processes, have resulted in far more severe environments in which concrete can and will corrode. A lack of understanding and experience extends beyond the contacting level. Many engineers, consultant, and inspectors do not fully comprehend the idiosyncrasies of lining concrete. When all the aforementioned parties converge upon a complex lining project, the potential for a perfect storm exists. The majority of lining failures, regardless of substrate, are often attributed to inadequate surface preparation.


Odor control systems do not magically make H 2S gas disappear from the headspaces of wastewater tanks and structures. Rather, odor control ventilation systems pull foul air over headspace surfaces, which are wet and inhabited by sulfur oxidizing bacteria. Additionally, fresh air supply to these headspaces brings an ample supply of oxygen to the aerobic bacteria, ensuring their health and the proliferation of corrosion. Dead spaces in the airflow patterns have been shown to create zones of higher corrosion in headspaces with operating odor control systems, as well. The ductwork and the other air handling and treatment equipment used for odor control systems suffer from biogenic sulfide corrosion when not constructed from corrosion resistant materials. The headspaces of the covered tanks and other wastewater treatment structures are an extension of the odor control air collection system. Hence, concrete and many metal surfaces in these headspaces must also be protected from corrosion Because the sulfide species are in chemical equilibrium in wastewater environments, the free H2S gas removed by ventilation will invariably be replaced by more dissolved H 2S. The dissolved H 2S gas will, in turn, be replaced by the conversion of bisulfide (HS-) to aqueous H 2S. This means that, despite ventilation, H 2S gas will continue to be released into the headspace atmospheres and pulled across the surfaces upon which it will condense and/or be absorbed and be transformed by the ever-present sulfur-oxidizing bacteria to sulfuric acid. Two conditions would mitigate biogenic sulfide corrosion. The H 2S gas concentrations would have to be below 2 ppmv, and the surfaces over which the headspace air was pulled would have to be dry. Neither condition typically occurs in the subject headspaces. If these two conditions exist, they would be extremely short-lived. Creating these conditions through more air changes or better air sweeping is not pragmatic or economical. The end result, thus, is consistent with what we see in real-world field applications. Ventilation associated with odor control cannot mitigate corrosion related to biogenic sulfide production of sulfuric acid. Rather, it simply reduces the severity of sulfide corrosion to our infrastructure. Corrosion protection is therefore required for headspace substrates despite the presence of odor control air treatment systems. In short, corrosion and odor are related issues in wastewater applications and require separate control measures.


Sheet linings made from stainless steel can protect carbon steel substrates at lower initial direct cost for installation and subsequent direct inspection than weld overlay and thermal sprayed coating. Closely matched thermal expansion coefficients of ferritic and duplex stainless steel grades with carbon steel allow large "tile pieces" in reliable, leak-proof linings compared to linings from austenitic grades, simplifying and speeding installation. Sheet linings with ferritic and duplex grades typically have lower unit costs than weld overlay and thermal sprayed coatings. Ferritic and lean duplex grades resist corrosion and stress corrosion cracking in most alkaline pulping and liquor recovery environments. Super-duplex grades can replace acid-resistant brick linings in D-stage bleaching equipment, including pre-retention tubes and towers. Carefully specified sheet linings of ferritic and duplex stainless steels, professionally installed in accordance with longstanding industry standards, are reliable and economical protective barriers, especially compared with weld overlay, in many applications in modern pulp and paper mills. Application: Mill maintenance departments can increase the reliability of fixed equipment at substantially lower cost by following recommendations in this review. Application: Mills should be aware that the conventional NH4Cl method for measuring the free lime content in lime mud does not work. It gives a free lime value that is low and cannot be used to assess the extent of overliming in the causticizing plant.


Bennett D.C.,Corrosion Probe Inc | Jackson C.E.,Nautilus Loss Control LLC
PEERS Conference 2015: Sustainable Solutions for Our Future | Year: 2015

TIP 0416-26 describes a modern process for systematically designing a cost-effective inspection plan for every part of a recovery boiler. Following the HP's guidance systematically focuses inspections where damage mechanisms occur, and eliminates them where there is no damage mechanism. Match the inspection and NDT method to the damage mechanisms, and the likelihood of finding and accurately quantifying the damage is greatly increased. In short, look in areas where we know problems occur, and refrain from looking where damage does not or cannot happen. This reduces outage time and cost, and can allow longer intervals between outages.


Spotten R.,Corrosion Probe Inc
NACE - International Corrosion Conference Series | Year: 2013

Coating manufacturers go to great lengths to produce quality products and provide sound technical recommendations for individual projects. This paper discusses several case histories where the coating manufacturer, by their errors, caused a coating failure. Among the topics discussed are quality control methods, raw material availability and supply issues, color matching and batch controls, inventory management and product shelf life, excess or aged product rework, and botched recommendations. © 2013 by NACE International.


Nixon R.,Corrosion Probe Inc
Journal of Protective Coatings and Linings | Year: 2013

The basic make up of concrete, characteristics of uncoated concrete that make it susceptible to attack in industrial structures, and main mechanism of concrete deterioration is discussed. There are different types of concrete but all are made from the same types of ingredients. Concrete deterioration can be divided into three types, chemical, physical and thermal. Chemical mechanisms of concrete deterioration begins with a chemical reaction. A chemical substance in the environment comes in contact with a concrete structure, and a reaction occurs between the chemical and the paste. The reaction weakens, dissolves, or otherwise changes the paste, so that the paste can no longer hold the concrete together. Microorganisms such as bacteria and tiny marine organisms called mollusks, can cause concrete to deteriorate. Physical mechanisms start with a physical attack from external objects or equipment. Concrete expands and contracts as temperature rise and fall, causing deterioration.


Spotten R.,Corrosion Probe Inc
Materials Performance | Year: 2014

Coating manufacturers go to great lengths to produce quality products and provide sound technical recommendations for individual projects. This two-part article discusses several case histories where the coating manufacturers, because of their errors, caused a coating failure. Among the topics discussed are quality control methods, raw material availability and supply issues, color matching and batch controls, inventory management and product shelf life, excess or aged product rework, and botched recommendations. The discussion began in Part 1 (October 2014 MP).


Spotten R.,Corrosion Probe Inc
Materials Performance | Year: 2014

Coating manufacturers go to great lengths to produce quality products and provide sound technical recommendations for individual projects. This two-part article discusses several case histories where the coating manufacturers, because of their errors, caused a coating failure. Among the topics discussed are quality control methods, raw material availability and supply issues, color matching and batch controls, inventory management and product shelf life, excess or aged product rework, and botched recommendations. The discussion will continue in Part 2 (November 2014 MP).

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