Effective corrosion management demands a holistic approach: Experts

From material selection to cooling tower management, every small decision affects long-term equipment reliability

Corrosion continues to be one of the most persistent challenges for the chemical and pharmaceutical industries, affecting equipment reliability, safety, and productivity. The issue goes far beyond material degradation, stemming from design choices, process conditions, and operational practices that often fail to anticipate real-world stresses. 

Leading industry experts shared their insights at the at the maiden conference titled “Corrosion Risk Management and Process Safety in Pharma and Chemical industry” organized by Indian Pharma Post and Indian Chemical News in association with Alleima on October 15, 2025, in Hyderabad. 

The panel discussion, “Combating Heat Exchanger Tube Corrosion in Pharma and Chemical Industry,” was moderated by Pravin Prashant, Executive Editor, Indian Pharma Post. 

Venkata Prasad K., Unit Head, Deepak Nitrite stressed on the fact that corrosion control isn’t just about material selection but requires disciplined operations, good design practices, and the involvement of experienced professionals. 

“In the pharma and chemical industries, corrosion of heat exchanger tubes remains a major challenge. Every chemical and process condition behaves uniquely, and the rate of corrosion varies accordingly. We often encounter pitting corrosion, where small localized attacks penetrate deep into the tube wall. Another serious issue is stress corrosion cracking, which occurs when the tube’s internal stress combines with environmental factors, often leading to sudden and catastrophic failures without prior warning. Fouling corrosion is another concern, typically caused by inadequate cleaning or poor maintenance practices. Similarly, erosion corrosion results from improper design choices, particularly when fluid velocity or tube sizing is not optimized during the design phase,” mentioned Venkata. 

“Compromising on these parameters to cut project costs can significantly accelerate erosion-related damage. Lastly, galvanic corrosion can occur when dissimilar metals, such as stainless steel tubes paired with less noble materials, are used together, leading to localized attack at the interface. Corrosion, therefore, is not merely a metallurgical or material issue; it is a multidisciplinary challenge that demands sound design practices, operational discipline, and the involvement of experienced professionals right from the design stage,” he added further. 

C. V. Rajulu, Industry Consultant emphasized the importance of safety culture and operational discipline in the chemical industry, noting that a person careless about personal safety cannot be expected to maintain plant safety. 

“We must reflect on what kind of safety culture we are passing on to the next generation. Cultural change takes at least a decade, and if an individual lacks a sense of personal safety, it is unrealistic to expect them to ensure safety within the plant. This observation is particularly relevant for the many young professionals entering the industry today. The corrosion in chemical plants often arises not only from improper material selection but also from poor operational and engineering practices. In large continuous process industries such as chemicals and fertilizers, even minor failures, particularly in components like heat exchangers, can trigger major shutdowns or even catastrophic accidents,” said Rajulu. 

“The cost of such risks is rarely accounted for during project planning. I recall an incident involving a Grignard reaction where THF vapor, after condensation in a heat exchanger, came into contact with water that had inadvertently leaked in. When the contaminated THF was recycled back into the reactor containing magnesium, it led to a violent reaction and a plant explosion. This highlights how a small component like a heat exchanger, though a minor part of total plant investment, carries significant risk potential,” he added further. 

Abhilash Pasham, Associate General Manager - Central Engineering & Projects, Dr. Reddy's Laboratories explained that while metals are the most versatile material for industrial applications, their biggest drawback is corrosion. 

“When we compare materials like metals, graphite, and glass, each comes with its own strengths and challenges. Metals are highly versatile as they can handle a wide range of operating conditions and allow flexible temperature ramp-ups. However, their biggest drawback is corrosion, particularly around weld joints, which leads to frequent failures and maintenance issues. Cleaning and descaling metallic surfaces is also difficult, especially when scaling builds up over time. Among the three materials, metals generally perform best in terms of operational versatility, but they are prone to sudden failures caused by corrosion. While industry testing and periodic inspections are common, they are not always sufficient to prevent contamination or predict failure. Hence, selecting the right metal and monitoring corrosion effectively are critical,” said Pasham.

“Graphite, on the other hand, performs exceptionally well in highly corrosive environments, especially at extreme pH levels. However, it has its own limitations as it is brittle, sensitive to mechanical stress, and can easily crack during cleaning or under pressure. Often, micro-cracks introduced during cleaning can later propagate into major failures.Glass equipment shares some properties with graphite — it offers excellent corrosion resistance but cannot withstand rapid temperature changes or high pressures. Cleaning and inspection of glass components are also challenging, particularly in complex assemblies like tubes,” he added further. 

Paresh Haribhakti, Managing Director, TCR Advanced Engineering Services advocated for better design practices that include inspection accessibility to monitor internal conditions effectively, preventing avoidable corrosion and improving plant reliability. 

“When we work with an existing plant, the design is already finalized, leaving very little scope for change. In such cases, it’s up to the operations team to deeply understand how to run the equipment effectively under given conditions. The first and most important thing is to understand the corrosion protection mechanism. For example, stainless steel protects itself through a passive chromium oxide film. The moment this passivity is broken, whether due to chlorides or alternating acidic and basic environments, corrosion begins. Such situations must be avoided through proper monitoring and control,” said Haribhakti.

“The velocity of the fluid is another critical aspect. Ideally, it should be maintained at around three feet per second. When velocity drops below this, the chances of pitting and corrosion increase significantly. I have also seen that preservation during shutdowns is often neglected. If equipment is not properly drained and dried after hydrotesting, stagnant fluids and oxygen pockets can cause severe corrosion before the next startup. Paying attention to these details can substantially extend the life of existing components. The microstructure of the material is equally critical. If we define and control microstructural requirements at the design stage itself, I believe we can eliminate nearly 50% of corrosion-related failures,” he added further.

Jyoti Shankar Jha, Senior Lead Scientist, Alleima India mentioned that before jumping to design-related conclusions, it is essential to first understand the real problem. 

“I believe that before jumping to design-related solutions, it’s crucial to first understand the actual problem. Many times, the solution is quite close — but without identifying the root cause, we end up addressing symptoms instead of fixing the issue. I’ve seen that in several cases, material selection is done based on assumptions rather than consultation, which leads to failures during plant operation. That’s why I always emphasize the need to take inputs from material scientists and industry experts before deciding on the right material for a given process condition,” stated Jha.

“I also think that conducting a proper root cause analysis is essential to prevent corrosion, especially in the pharma and chemical industries. Increasing chloride levels and high total dissolved solids (TDS) in cooling water systems are creating serious challenges. Even though some believe higher TDS levels are fine, in reality, they accelerate corrosion and erosion in heat exchangers and cooling towers. So, it’s extremely important to monitor and manage cooling water quality carefully to ensure the longevity of plant equipment,” he added further.

Ganesh Prasad, Technical Marketing Specialist, Alleima India pointed out that failures happen not just from using the wrong material but also from procuring poor-quality material. 

“When designing heat exchangers, engineers often rely on mechanical design codes that specify parameters such as pressure and thickness. These codes may state that no corrosion allowance is required, but actual plant operating conditions frequently differ from design assumptions, resulting in corrosion problems in real-world settings. Therefore, corrosion considerations must be built into the design process from the very beginning,” said Prasad. 

The process licensor should recommend materials based on actual process conditions, and this guidance should be carried through consistently from the licensor to the end user. In practice, however, material selection is often done either at the licensing stage or only after a failure has occurred, which is far from ideal. From a metallurgical standpoint, failures occur not only because of incorrect material selection for the given process but also due to the use of poor-quality material even when the correct grade has been specified. This highlights the importance of both proper material selection and strict quality control during procurement to prevent corrosion-related failures,” concluded Prasad.