Smarter Heat Management: Choosing the Right Exchanger for Industrial Systems

Industrial processes rarely dictate simple demands. Fluids entering a system may vary in temperature, pressure can be a concern, and space often becomes an important factor. At the same time, a process requires reliable thermal management without being a burden to upkeep and maintain. This is why purposefully developed heat transfer products play an important role in a process.

A heat exchanger is a particularly useful type of equipment capable of passing thermal energy between two fluids. The correct application, however, goes beyond merely comparing specifications.

Operating conditions, materials, installation, maintenance, and even the cost all play an important role in determining the most effective heat exchanger in a given application.

The Role of Heat Transfer Equipment

Heat exchangers form an integral part of chemical, power, food, HVAC, oil & gas, and industrial facilities. A basic overview of the function performed by heat exchangers reveals that they have the simple task of transferring heat from one fluid to the other as efficiently as possible.

The problem, however, is ensuring that this most basic of functions can occur under the specified operating conditions.

A number of variables, including temperature differences, fluid properties, fouling potential, pressure limitations, and corrosion resistance, have to be taken into account when considering the best heat exchanger option for an application. What makes sense in one scenario may not be viable for another simply due to differences in material compatibility.

For instance, liquids to be heated or cooled in a process may have different flow characteristics. A simple liquid-to-liquid process with little or no impurities bears very little resemblance to fluid-to-fluid or fluid-to-gas scenarios. Process engineers, therefore, have to take the entire spectrum of characteristics into account, rather than simply basing their choices on heat transfer capabilities.

When a Custom Heat Exchanger Should Be Used

Standardized equipment can be highly effective in specific applications. However, some industrial processes and systems impose constraints that may be difficult to overcome when relying on existing equipment.

A custom heat exchanger can be developed around an application’s unique requirements, including factors such as:

• Thermal duty

• Temperatures and flow rates

• Space constraints

• Operating and design pressures

• Material compatibility

• Cleaning and maintenance requirements

• Allowable pressure drop

Not every situation dictates that a completely custom exchanger has to be developed from ground-up, however. There are also scenarios where changes to an established configuration allow a specific type of exchanger to fit within the constraints of an application.

A fundamental requirement in any custom exchanger order pertains to the provision of all relevant data. If the information provided proves to be inadequate, it can significantly impact the ability of the exchanger to perform under real-world operating conditions.

The Importance of Material Selection

Material selection is especially important for highly corrosive fluids and extremely high operating temperatures.

Alloys such as stainless steel, nickel, carbon steel, titanium, and other materials can be utilized depending on the application and its operating environment. Every aspect of the process has to be taken into account when specifying the correct material type, including the chemical properties of the fluid, temperature, pressure, mechanical limitations, and service expectations.

A lower initial purchase price may not prove to be cost-effective if, for instance, material selection contributes to heightened corrosion risk or complicated maintenance schedules.

The Value of Spiral Heat Exchangers

Space limitations and maintenance requirements can be just as important as maximizing heat exchange performance. Spiral heat exchangers utilize coiled flow paths in a condensed design to enable heat transfer between two process fluids.

A defining characteristic of spiral heat exchangers pertains to the fact that they offer excellent flow patterns that allow considerable versatility and performance within a relatively compact profile. In some cases, these exchangers can even be utilized in applications where fouling can limit the performance of other types of exchangers.

The smooth and uninterrupted flow of fluids through the exchanger can, in some cases, reduce the likelihood of material buildup or deposits that would otherwise hinder performance. It should additionally be noted that this characteristic, as well as the benefits of a spiral design, are largely dependent on the properties of individual fluids. Conditions such as temperature, viscosity, and solid content can have a significant impact on the performance of the exchanger.

Spiral heat exchangers can be considered for wastewater treatment, chemical processing, heat recovery, and other industrial duties.

Getting the Most Out of a Heat Exchanger

The right equipment selection only plays a small part in maximizing heat exchanger performance. In reality, heat exchanger operations require consistent long-term efforts, including maintenance and cleaning. Exchangers should be regularly observed for potential issues, such as changes in temperature approach, pressure drop performance, fluid flow rates, and overall thermal performance. Gradual decreases in thermal performance capability of the heat exchanger can signal the onset of fouling, scaling, corrosion, flow restrictions, and other issues. Routine maintenance and inspections can ensure such issues are discovered and addressed at the earliest possible moment following a predictable schedule that is specific to the fluid involved. An exchanger handling clean water in a closed system will likely demand far less maintenance when compared to an application involving highly fouling substances.

Furthermore, regular performance assessments provide engineers with opportunities to understand how a heat exchanger is performing as a whole.

Establishing a baseline performance reference following installation or after a thorough cleaning campaign can assist an engineer in spotting any irregularities based on comparative performance values.

Design Considerations That Can Enhance Performance

There is no single exchanger type which is best suited for every application. Shell-and-tube heat exchangers, plate exchangers, air-cooled heat exchangers, spiral heat exchangers, and other designs all have their unique strengths and weaknesses. A heat exchanger’s selection should, therefore, rely on the overall heat exchange environment rather than on a single parameter. An exchanger type should be chosen based on a combination of temperature and pressure considerations, materials selection, potential fouling effects, accessibility, footprint, future growth expectations, and maintenance requirements. This same application-centric approach should, in fact, be taken for any equipment choice regarding heat transfer products. Instead of comparing heat transfer equipment options based on a singular consideration, the focus should be on finding the most effective all-around option for a specific application.

Conclusion

Thermal control necessitates a careful evaluation of equipment options in order to ensure that the physical limitations dictated by a process do not limit the performance of an exchanger. Whether a facility is looking to utilize standardized exchangers or is considering a specialized option, engineers should analyze the operating conditions that can impact the performance of an exchanger. Companies faced with challenging space, temperature, pressure, or any other limitations should benefit from collaborating with a competent engineering team that can analyze the requirements of a process and develop a corresponding heat transfer solution. As a heat transfer engineering company, Kinetic Engineering Corporation can assist clients in identifying the correct products for particularly challenging industrial applications. We are capable of evaluating specification information relating to a process and developing a solution suitable for a given application.

FAQ

1. What is the primary function of a heat exchanger?

A heat exchanger is used to transfer heat from one fluid to another without allowing the two fluids to intermix. The equipment can be used to cool, heat, condense, evaporate, or recover heat from one or both fluids.

2. Why might it be beneficial to consider a customized heat exchanger?

Custom heat exchangers can be utilized in applications where a conventional heat exchanger would not be fit for purpose due to material limitations, pressure, required dimensions or connections, or spatial limitations.

3. Can spiral heat exchangers be used for fouling applications?

Spiral heat exchangers can be utilized for some fouling applications since the flow characteristics in a spiral configuration allow the heat exchanger to perform well in many situations where fouling can impede performances. This, however, is largely contingent on the fluids being processed and should be carefully considered with regard to the details of the intended application.

4. How can one get the most out of a heat exchanger?

Proper operating and maintenance practices are crucial to maximizing the performance of a heat exchanger. Exchangers need to be regularly cleaned, inspected, and monitored to identify any performance deviations as early as possible. Following a well-structured maintenance schedule based on a precise evaluation of the process environment can enhance the performance of a heat exchanger.