Enhancing operational efficiency in the food and beverage industry: the importance of plate heat exchanger maintenance

In the fast-paced world of the food and beverage industry, where unplanned downtime and product wastage can be detrimental to business operations, focusing on the fundamentals is crucial.
Ben Green, food and
water divisional manager for the UK and Ireland at Alfa Laval, delves into the potential repercussions of neglecting plate heat exchanger (PHE) maintenance and the pivotal role of preventive measures in ensuring productivity, especially when operating on razor-thin profit margins.
While plate heat exchangers (PHEs) are precision-engineered pieces of equipment, it is estimated that thousands of them are poorly maintained, often causing hidden costs that erode your bottom line as you strive to optimise business operations.

The significance of gasketed plate heat exchangers (GPHEs) in food and beverage 

Processing:
In food and beverage processing, the gasketed plate heat exchanger (GPHE) takes centre stage. These GPHEs employ elastomeric gaskets affixed to metal plates to create seals, separating fluids into distinct channels. These channels, which can operate in counter- or co-current configurations, enable efficient thermal transfer. It is the expansive surface area of GPHEs that makes them renowned for their high efficiency.

Challenges Faced by GPHEs:

Fouling:
The most common challenge in GPHEs is fouling, resulting from the crystallisation, decomposition, or settling of biological matter and particulates. Fouling becomes more likely with incorrectly specified or inadequately maintained GPHEs as it disrupts flow patterns or causes blockages. In the dairy industry, fouling is prevalent, particularly when whey protein deposits accumulate during pasteurisation. Such build-up, stemming from milk protein breakdown, can be predicted to some extent, but it still occurs without proper maintenance. Fouling is challenging to remove entirely, often leading to unplanned downtime and product spoilage. Hence, the wisest strategy is to prevent fouling from the outset.

Other Risks:

Over time, all-metal equipment, like GPHEs, is prone to corrosion. Crevice corrosion can occur when each plate is sealed onto the heat exchanger. The polymers used for gaskets can release chemicals that intensify corrosion and cause gasket failure. Polymer gaskets can also degrade due to factors such as incompatible fluids, UV light exposure, or excessive pressure. This can be mitigated through proactive maintenance and prudent gasket material selection.

Choosing the Right Gasket Material:

Selecting gasket materials requires a deep technical understanding of chemical interactions and should be customised for specific applications. With over 1,700 polymer grades, vulcanising chemicals, and processing materials to consider, material choice is paramount. For instance, chloroprene rubber is unsuitable for high temperatures, while special fluorocarbon gaskets, such as those made from FKTM can withstand them. Similarly, EPDMP is highly resistant to acids but may not be the best choice for processes involving oils. The choice of gasket material is critical and should align with the specific process requirements.

Consequences of Reactive Maintenance:

The problems mentioned above are more likely to occur when relying on reactive maintenance, also known as ‘running to failure.’ This approach is a false economy as it results in greater future costs. Equipment failure can lead to costly unplanned downtime, staff safety risks, product wastage and equipment damage. Fouling deposits act as insulation, reducing heat transfer efficiency and overall yield significantly over time. Corrosion can release toxic heavy metals into the environment, and insurance companies may be hesitant to pay out without proof of servicing. Notably, many reports suggested that up to 2.5% of global CO2 emissions could be attributed to PHE fouling, emphasising the need for sustainability, especially in the post-pandemic era.

Implementing an Effective Preventative Maintenance Strategy:

In a time when businesses operate on slim margins, allowing equipment to run to failure can be a costly mistake. Avoiding unplanned downtime and maximising productivity is essential. Despite the ubiquity of GPHEs, expert servicing is crucial for this highly technical equipment. Preventative maintenance can be seen as a “marginal gain” that plays a crucial role in remaining competitive.

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