Whether you’re in the middle of a busy production season or just wrapping up a cleaning cycle, one thing’s for sure: keeping your heat exchanger in top shape should always be on your radar. A well-maintained unit runs more efficiently, lasts longer, and helps you avoid costly downtime or product contamination.
So, what does smart maintenance actually look like for a shell and tube heat exchanger? Let’s break it down with five practical tips you can apply year-round.
1. Schedule Routine Maintenance (and Stick to It)
Heat exchanger maintenance usually means taking the equipment offline—so yes, it can feel like a disruption. But planning ahead makes a huge difference.
Pick a date during lower production periods.
Order gaskets or replacement tube bundles well in advance.
Coordinate with contractors early—don’t wait until their calendars are full.
Skipping scheduled maintenance often leads to bigger problems later. Either you plan the downtime, or the downtime picks you. Spoiler alert: the latter is never convenient.
2. Keep an Eye on Fouling and Corrosion
A fouled exchanger is a slow exchanger. Material buildup reduces heat transfer, invites corrosion, and in worst-case scenarios, becomes a fire risk. Inspect regularly—both the tube side and the shell side—for signs of scaling, sediment, or corrosion.
If you catch fouling early, cleaning is quicker, easier, and less disruptive.
3. Monitor Your Heat Transfer Fluid (HTF)
Chemical-based HTFs don’t last forever. Over time, they degrade, lose efficiency, and can even become hazardous.
To stay ahead of issues:
Test the fluid while the system is running (hot fluid tells a truer story than cooled samples).
Take samples from different points in the system.
Consider quarterly testing for consistent insight into fluid health.
Healthy fluid means better performance and a lower risk of costly issues.
Test the fluid periodically; Processing Magazine noted that quarterly testing typically provides the best results.
4. Bring the Right People to the Table
Maintenance is a team effort. Involve your safety team, maintenance crew, and contractors from the beginning.
Use checklists to stay organized.
Share documentation in advance—like safety policies, maintenance logs, and OEM manuals.
Require credentials and training records from any outside vendors.
Clear communication ensures your maintenance day goes smoothly, safely, and efficiently.
5. Don’t Skip the Post-Cleaning Details
Once you’re done cleaning, finish strong:
Rinse out leftover chemicals or debris—especially after chemical cleaning.
Inspect gaskets and gasket covers. Replacements are inexpensive, but failures aren’t.
Document what was done and note any issues to watch going forward.
This final step is easy to overlook but critical for protecting product quality and keeping the exchanger sealed tight.
Keep Your Equipment (and Your Business) Running Smoothly
Routine maintenance might not be glamorous, but it’s one of the smartest investments you can make in your operation. Want help planning your next maintenance cycle, ordering spare parts, or upgrading your equipment?
The heat exchanger pros at Enerquip are here to help—contact us anytime.
Shell and tube heat exchangers are crucial in many industries, from oil and gas to food and beverage. Despite the differences in these fields, they share the need for well-maintained shell and tube heat exchangers to prepare products for consumers.
When using a shell and tube heat exchanger, the fluid that is more likely to corrode or foul is typically placed on the tube side. This is because the tubes are easier to clean or replace than the shell. This makes it vital for operators to know how to properly clean and maintain the tubes.
Shell and tube heat exchangers come in various sizes and configurations. Some are easier to clean than others, mainly because some have tube bundles and bonnets that can be easily removed from the shell, while others are connected to the body of the exchanger. Knowing the type of bonnet your exchanger has and the appropriate cleaning method is crucial when purchasing the exchanger.
There are several ways to clean the tubes of a heat exchanger, each with pros and cons. It’s important to choose the right method for your specific machine and operation.
Chemical Cleaning
Chemical cleaning is effective for fixed-channel box designs, which can be particularly challenging to clean because the tubes are not detachable from the shell. The chemicals can be circulated through the tubes or cascaded. This approach is advantageous for exchangers with substantial build-up, as the chemicals can remove more deposits than many alternative cleaning techniques.
However, chemical cleaning is one of the more expensive options. It often necessitates mechanical cleaning afterward to eliminate any residual substances that could contaminate future batches. Additionally, this method can be time-consuming and pose potential environmental risks, depending on the type of chemicals used and waste management practices.
Hydroblasting
Hydroblasting uses high-pressure water to blast away debris or deposits in the tubes. Hydroblasting does not involve the use of hazardous chemicals, making it a more environmentally-friendly cleaning option.
This method can be done manually or with an automated system. The manual approach involves an operator using a high-pressure hose to clean each tube individually, which is effective and relatively inexpensive but can result in uneven cleaning and safety concerns due to the high water pressure.
Automated systems, such as flexible lance and rigid lance systems, allow multiple tubes to be cleaned at once, saving time. Flexible lance systems are suitable for U-tube heat exchangers and those with curved tubes, while rigid lance systems are better for exchangers with straight tubes due to the higher water pressure they can provide.
While hydroblasting is effective, if the water pressure is not carefully controlled, could weaken the tubes and create leaks. The water and debris generated during the hydroblasting process must be properly collected and disposed of, which can add to the overall cost of the cleaning operation.
Choosing the Right Cleaning Method
When it comes to selecting the best cleaning method for your heat exchanger tubes, there are several factors to consider, including the type and severity of the deposits, the materials of the heat exchanger, the available budget, and the overall impact on your operations.
In general, chemical cleaning may be the preferred option for larger heat exchanger systems or for removing stubborn deposits that are difficult to access. However, if environmental concerns or the potential for residual chemical deposits are a priority, hydroblasting may be the better choice.
It’s important to carefully evaluate the pros and cons of each method and consult with experienced professionals to determine the most suitable approach for your specific heat exchanger cleaning needs. Regular maintenance and cleaning are essential for ensuring the optimal performance and longevity of your heat exchanger equipment.
As most manufacturers working with shell and tube heat exchangers know, fouling can be detrimental to an operation. It is crucial that all equipment used to process a product is working at its optimal capacity. To ensure this, manufacturers and operators need to take the time to inspect and clean shell and tube heat exchangers.
The complexity and time required for these tasks vary depending on the heat exchangers’ design and configuration. Manual inspection and cleaning might take a day or two, resulting in downtime. Therefore, it’s important to choose the best day to minimize losses and to plan ahead. Scheduling maintenance in advance helps manage downtime and ensures a smooth turnaround process.
Knowing When to Clean
In sanitary industries, like food, dairy and pharmaceutical, there are often well-established protocols established for the timing of heat exchanger cleaning. These cleanings are most commonly accomplished through the use of an automated CIP (clean-in-place) system that will clean and sanitize the tubing without having to disconnect the piping or exchanger parts. These cleanings are often done daily or weekly between batches of product.
Chemical Processing explained that over the past half-century, companies have changed the way they view scheduled maintenance days. In the past, cleanings took place one or more times a year. The years have brought equipment that is more reliable and requires fewer cleaning days. Today, the norm is closer to cleaning once every four to 10 years. Of course, this depends on the exchanger type and what it is being used for. Some materials that pass through an exchanger are less prone to fouling than others. For this reason, it is important that operators and manufacturers know the signs of fouling and the nature of the chemicals and products they work with.
There are many advantages to going several years without a cleaning. The fact that cleanings are less necessary indicates the resiliency and efficiency of the exchanger. It also means there are fewer days during which the company loses profit due to ceased production. However, there are some downsides to this as well. Chemical Processing points out that since the last turnaround day may have happened as long as a decade ago, fewer operators and maintenance experts will be familiar with the process of cleaning and inspecting the machines. Because of this, it is important that all people involved in the cleaning day be properly educated and prepared for it.
Getting Prepared
Chemical Processing advised people getting ready for a turnaround day to make a checklist of everything that needs to be completed on that day. This will help someone who is inexperienced or out of practice keep track of all necessary tasks. This list should include recording how the machine is operating just before you shut it down, whether all the measuring tools available make sense or if others would be best, layout dimensions for the machine and all its parts, and whether there is any damage or other factors that could cause harm to the product or machine later on. It is also important to have any replaceable spare parts on hand, like gaskets, O-rings and hardware, so that any damaged or compressed parts can be replaced before the unit is re-connected and brought back online. Because exchanger parts can be very heavy, it is also important to have a safe lifting plan with adequate clearance to remove bonnets, piping and other parts in order to gain access to the tube bundle.
How to Clean
It’s a good idea to take pictures of everything mentioned in the notes taken throughout the day. This will help explain any damage encountered and provide reference for the notes the person performing the turnaround takes.
There are many ways to clean a shell and tube heat exchanger, though most require being offline. The most widely chosen method is mechanical cleaning. This involves determining what kind of deposits you will be removing from the tubes. Deposits range from small amounts of silt to substances that are more difficult to remove, depending on the materials that are used in the exchanger. Once this is determined, decide which cleaning method is appropriate. Some common examples include brushes, used for lighter debris; calcite cleaners, used to remove stubborn calcite deposits which couldn’t be removed with acid; and metal tube cleaners, used for harder deposits.
Hydroblasting has also been commonly used, though precautions to reduce risk of injury or tube damage must be taken if managers choose to go with this option. Good Way explained this method involves water pressurized to 10,000 to 25,000 pounds per square inch, which is then blasted through the tubes to remove deposits.
Chemical cleaning is another preferred method, though it is a more expensive option. Chemicals that are mildly acidic will take off debris faster and more efficiently than a mechanical process. However, the tubes will still need to be cleaned of the chemicals used to prevent contamination or environmental hazards.
Editor’s note: This content was last updated 5/14/24.
A pivotal component across various operations, the shell and tube heat exchanger stands out as a cornerstone in many processes. In sectors like food, beverage, and dairy, its role in safeguarding consumers from contaminated products is paramount. Similarly, within the pharmaceutical realm, heat exchangers play a vital role in upholding the quality of medications.
The ramifications of a heat exchanger malfunction are significant. Contaminated products result in potential decreases in productivity and, in severe cases, damaging recalls that tarnish reputations. To avert such scenarios, regular review and servicing of the heat exchanger are imperative. Neglecting maintenance leaves heat exchangers vulnerable to corrosion and fouling, which in turn heightens the risk of leaks. These leaks can lead to undesirable mixing of product with cooling or heating fluids, rendering entire batches unusable. Additionally, the accumulation of corrosion and deposits within the exchanger compromises its efficiency, hindering the attainment of desired temperatures.
Corrosion leads to bigger problems
Like any piece of equipment, a shell and tube heat exchanger requires periodic maintenance, including cleaning, repairs, and ultimately replacement. Continuous use will inevitably lead to wear and, potentially, corrosion. The objective is to prolong the exchanger’s operational lifespan for as long as possible. Proper maintenance can extend its longevity for decades, involving meticulous and regular inspections of all components.
Ensuring the heat exchanger’s cleanliness is paramount throughout its lifespan. Prior to initial use, a thorough examination is necessary to confirm proper assembly and to prevent contamination of the tubes and shell by dirt, dust, or other contaminants.
Corrosion is an inevitable process that occurs over time, despite adhering to maintenance schedules. It arises from chemical reactions within or surrounding the heat exchanger. Different metals react differently with various substances. Stainless steel is an optimal choice for exchangers, particularly when handling potentially corrosive substances that could harm other metals like copper alloys. High-alloy grade stainless steel can withstand corrosion from most acidic, alkaline, and chlorinated substances. However, even though the metal exhibits high resistance to corrosion, it will gradually deteriorate with time.
The best way to prevent corrosion is to make sure only the best substances for the exchanger’s material makeup enter the machine. Using the correct chemicals to treat and clean the tubes is essential. This information should be obtained before you begin using your heat exchanger to ensure you are prepared for its maintenance from the get-go.
Many heat exchangers use water as the heat transfer liquid. Tap water is generally of an acceptable quality to use in the machine. However, it is important to double check the water before putting it into the exchanger. The pH should be neutral, and the water shouldn’t be polluted or have any bacteria or other contaminates in it. If the water comes from a natural source, is should be treated before entering the tubes.
If the water isn’t treated or inspected before entering the exchanger, debris could enter the machine and block the chambers. To prevent this from happening, screens or filters can be installed to keep particles out. If they do enter, they will wear against the tubes and cause corrosion.
Regular monitoring of the heat exchanger’s condition aids in early detection of potential failures before fouling or contamination exacerbate the issue. Assessing water quality serves as an indicator of potential or ongoing failures; cloudy water suggests impurities. Additionally, recording temperature and pressure fluctuations can reveal emerging issues. Reduced efficiency may signal scaling, a solid precipitate formed from chemical reactions, which, over time, leads to fouling and corrosion. Monitoring other parameters such as tube thickness also provides insights into emerging problems.
Chiller tube maintenance is likely not on the top of facility managers’ minds during cold months. But just because they may not be in use, doesn’t mean you shouldn’t give them some attention during the winter season. In fact, this extended period of time when chillers are not a critical component of your building’s HVAC efforts is the perfect opportunity to address any chiller tube maintenance concerns.
Of the many components of a chiller, the tubes are one of the most impactful in terms of overall energy efficiency, according to The NEWS. Chiller tubes and coils can become dirty or coated with scale over time, which decreases their heat transfer capabilities. As a condenser’s heat transfer ability goes down, its energy consumption goes up – sometimes by 30 percent or more, according to the U.S. Department of Energy. A well-maintained system, therefore, can save energy and money. If your condenser was struggling to reach a full refrigeration load or was reaching higher pressures than expected, it’s likely you have buildup that’s increasing your energy spend.
Begin Your Chiller Tube Maintenance with Clean Tubes
An initial water cleanse is a good step toward cleaner tubes, but it shouldn’t be your only means to achieve greater energy efficiency. There will likely still be scaling left clinging to the tube walls after the cleanse is finished, especially considering that most chiller tubes have ridges in them.
A rotary tube cleaner, like the Goodway Ram-Pro sold by Enerquip, includes a brush that rotates to get into those grooves and can help immensely. Newer models of rotary tube cleaning systems also allow you to add antimicrobials and corrosion inhibitors onto the surface of the tubes to minimize future scaling.
Choose the brush you use with the rotary tube cleaner carefully, as different models are designed to clean specific types of fouling. There’s a big difference between removing softer fouling like algae and mud compared to tougher scaling and mineral deposits.
You may also consider using chemical descalers to tackle more difficult forms of buildup like calcium, rust and lime. However, before you choose chemicals to insert into your tubes, make sure they’re compatible with the equipment’s materials of construction. If your tubes were fabricated with an alloy that’s highly resistant to corrosion, such as stainless steel, this may be less of a concern.
Cleaning your tubes should be at least an annual or biannual task, and doing so during the colder months can give you ample time to address any issues before the weather warms up again.
Do an Eddy Current Test
Many chillers go through eddy current testing after fabrication and installation to test for any damage that may have occurred before the unit is fully operational, Process Cooling explained. It’s also a good method to test for issues that may arise during the lifetime of the chiller.
An eddy current test may be able to detect small defects that can lead to leaks, but it shouldn’t be confused with an actual leak test, Texas Eddy Current explained. An eddy current test, sometimes called a magnetic field test, can highlight corrosion, erosion, mechanical damage and more. It can also indicate whether your tube walls have lost thickness over the years, Facilities Net reported. To conduct this test, a metal probe that creates a full-circle magnetic field is inserted into the tube. As the tester moves the probe through the tube, the magnetic field will either remain stable or show signs of a disturbance. Those signals indicate an issue at that location.
You don’t necessarily need to do an eddy current test each time you clean your tubes. Once every two or three years for your chiller or three to five years for your evaporator should be sufficient.
Treat Your Water
The quality of the water that enters and flows from your chiller plays a big role in determining how often you should perform chiller tube maintenance and cleaning. When you know the water quality in your area, you can take proactive measures to prevent scaling and fouling in your tubes.
“When you know the water quality in your area, you can take proactive measures to prevent scaling.”
Closed-loop systems, which are most common in chillers, generally require a one-time chemical treatment to reduce the risk of fouling. If you have an open-loop system, which may be found in condenser systems or atmospheric cooling towers, you’ll likely need to arrange for continuous chemical treatment. In any case, water treatment should be tailored to the unique qualities of the local water source. A water treatment specialist in your area is the best resource to consult.
Though keeping the risk of fouling at a minimum may be your highest priority, you should also keep in mind other conditions of the water, such as the temperature and flow rate, Contractor Business explained. Colder water is generally more efficient to use in chillers. In fact, if your chiller isn’t running optimally and you aren’t prepared to clean the tubes just yet, lowering the temperature may be a good temporary solution for improving efficiency. Don’t mistake this as a long-term fix, though – if you’re looking for sustained improvement, it’s critical to remove scale and other buildup in the tubes.
The flow rate should generally be between 3 and 12 feet per second. Fall below this range and you’ll get laminar flow that reduces the efficiency of the chiller. Higher flow rates can cause the equipment to vibrate and shake, and increases the risk of damage to the tubes.
Create a Prevention Plan for Your Chiller Tube Maintenance
Setting aside enough time to conduct thorough chiller tube maintenance and inspection is a great first step toward lasting energy efficiency, but it’s important to plan for the future, too. Every system is different, so you should create a plan to keep your unit running well for years to come.
Creating a daily operating log will help you visualize small day-to-day changes in the chiller’s performance, which will indicate how often you should repeat the cleaning process. It will also clue you into small issues that occur. Identifying and addressing these before they escalate into larger problems can help you maintain a functioning chiller for longer.
In time, you may start to notice patterns in your chiller’s performance. This will help you create a schedule for inspections and maintenance.
Know When to Replace Your Chiller
Every chiller will be replaced sooner or later. Though these units can generally be relied upon for several decades, they’ll eventually become more costly to maintain than it would be to install a newer, more updated model. If your chiller is presenting frequent issues and is close to 25 or 30 years old, it’s likely ready to be retired, Facilities Net explained.
When choosing your next model, seek out a manufacturer that can provide reliable, high-quality equipment. The engineers at Enerquip are here to help identify shell and tube requirements for a wide range of assets, including chillers. Request a quote.
Keeping your shell and tube heat exchanger contaminant-free is critical to creating a high-quality final product. However, every company must face a hard (and sometimes calcified) reality: Fouling happens. When it does, the built-up matter needs to be removed, and the equipment sanitized.
Of course, there are some downsides to cleaning your shell and tube heat exchanger. The process usually needs to be done offline, thus eliminating some production time. Reducing the number of hours your equipment is productive will have an impact on your company’s bottom line. Then again, so will fouled material if allowed to continue to build up in your equipment. Further, excessive buildup will reduce heat transfer efficiency, causing processes to increase in price and length of time.
Thus, equipment operators must strike a balance between regular cleaning times and fouling accumulation. To make sure your shut-down day has as low an impact on your business as possible, take these factors into consideration when planning your cleaning schedule:
Fouling allowance
The Tubular Exchanger Manufacturers Association recommends that companies determine well in advance what they would consider an allowable amount of fouling and take these into consideration when calculating heat transfer resistance, as well as determining a cleaning schedule, according to Conoco Consulting Corp. When your level of fouling nears this level, you’ll know it’s time to plan your next shut-down day, though you’ll usually define a loose maintenance schedule when calculating your fouling allowance.
Engineers typically determine the allowable amount of fouling during the design stage, according to InTechOpen, an open access science, medical and technology book publisher. This is an important factor to take into consideration when calculating the heat transfer coefficient. A higher fouling allowance will result in a lower coefficient, but may also result in fewer necessary cleaning days.
Fouling allowance can be thought of in several different ways, including a percentage of fouled matter as compared to the overall surface area, how clean the equipment is or what the maximum fouling resistance should be.
Cost of operation
Keeping a close eye on the cost of your operations is a good indicator of efficiency and productiveness. As fouling builds up, so too will your cost of operations per hour. The increase in cost is due to greater energy needed to achieve the same heat transfer rate, a lower rate of production, or a combination of the two.
Referencing a 1981 report, “Optimum Cycles for Falling Rate Processes,” published in The Canadian Journal of Chemical Engineering, Conoco Systems suggested determining when your process will reach its minimum value to the company. When calculating this, you’ll need to take several factors into consideration, including the cost of cleaning, the cost of the lost production time and any interest accumulated due to borrowed funds, if applicable. Compare all this to the cost of reduced efficiency of the heat exchanger.
Your production cycle
No one knows your production cycle better than you and the people at your company. You know when your busy seasons are and when business slows down, as well as when you’ll have three-day weekends. Use this knowledge when planning out your cleaning schedule.
With this information, you’ll be able to choose a day or several days to shut down your plant for much-needed cleaning without taking away from a busy or usually productive day. Additionally, you know your staff won’t feel pressured to make up for lost production time when everything is shiny and new once more. If it makes sense to schedule cleaning over a three-day weekend, take advantage of the day off and turn it into a day offline.
Every operation is different and will require different intervals between cleaning. Some plants may require multiple shut-down days each year; others might be able to hold off for a decade using effective fouling mitigation tactics and discretionary maintenance tasks. It’s important to decide what’s right for your company so you can ensure consistent quality at as low a cost of production as possible and with minimal disruption to normal business operations.
If you’re in the market for a new shell and tube heat exchanger, reach out to the helpful engineers at Enerquip. When you explain your operation and needs, they’ll be able to work with you to design and fabricate a custom shell and tube solution that works.
When considering your options for a new shell and tube heat exchanger, one important factor is the tube configuration.
Various options benefit different types of processes. For example, a floating head configuration is better suited to processes prone to significant thermal expansion because the tubes aren’t constrained by the tube sheet or the shell, and can therefore expand or vibrate without risking damage to the rest of the equipment.
Beyond taking into account the intended use for the exchanger, and other elements like location of the exchanger or the product that will be introduced to it, it’s also a good idea to think about cleaning methods. Not all cleaning strategies are appropriate for all configurations, but all exchangers will need to be properly and thoroughly cleaned sooner or later. It’s best to know what cleaning capabilities you’ll have with a particular configuration beforehand so you can factor it into your decision, or at least prepare for new sanitation needs.
How to Clean a Fixed Tubesheet Shell and Tube Heat Exchanger
A fixed tubesheet is a popular shell and tube heat exchanger design for several reasons, including cost effectiveness and ease of cleaning. Since the tubes are straight and the tubesheet is welded straight to the shell, construction is relatively simple.
To clean a fixed tubesheet shell and tube heat exchanger, the bonnet first needs to be removed. This is a relatively simple task with this configuration. The insides of the tubes can be cleaned mechanically, and the straight configuration makes it easy for brushes, hoses or other cleaning supplies to be fed into the bores. The tubes can also be cleaned chemically, and running the cleaning solution through the tubes is fairly easy, again, because of the straight design.
While cleaning the tubeside is pretty straightforward, shellside cleaning is a bit more complicated with fixed tubesheet designs. Because the tubesheet is welded to the shell itself, it’s nearly impossible to mechanically clean the outsides of the tubes. Chemical cleaning must be done instead. However, it’s critical that operators are confident that the chemical cleaning agent can be thoroughly rinsed from the shellside before operation reconvenes. Leftover residue can damage the material of construction or contaminate the product.
The bonnet type plays a role in how easy it is to reach the tubes. L-type and N-type bonnets, which have removable covers, grant easy access to the inside of the tubes without removing any piping. The M-type bonnet does not have this removable cover, which means the entire head needs to be taken off to access the tubes.
The difficulty in shellside cleaning isn’t always a problem. If the shellside of this heat exchanger is only used for clean fluids rather than fouling services, there’s virtually no need for future cleaning.
How to Clean a U-Tube Shell and Tube Heat Exchanger
As the name suggests, the tube bundle of a U-tube exchanger is curved at the end and returns the fluid back to the same side it entered, rather than providing a point of exit on the opposite end of the exchanger. Thus, only one tubesheet is required, leaving the other end free to expand or vibrate without risking damage to the rest of the construction.
While the U-shaped bend provides benefits in some ways, it becomes cumbersome when it comes time to clean the equipment. The curve at the end of the tube makes it challenging for mechanical cleaning, unless a flexible-end drill shaft is utilized. Chemical cleaning is possible, but certain types of fouling, make it challenging – particularly scaling that hardens to the sides of the tubes and is difficult to remove without physical force. Additionally, with scales forming at the point of the bend, it may be difficult to assess whether all fouling has been completely removed. The solution to this dilemma is to use clean fluids on the tubeside with this configuration, Thermopedia pointed out.
An articulating brush is advantageous for cleaning U-tubes.
While cleaning the interior of the tubes on U-tube exhchangers is a challenge, the shellside is very easy. Since there’s only one tubesheet, deconstruction is simple. Once removed, the shell and the outside of the tubes can be cleaned easily.
How to Clean a Floating Head Shell and Tube Heat Exchanger
The floating head tube bundle configuration is the best of both worlds. Only one end of the two tubesheets is welded to the shell, allowing the other to expand as needed according to the process it’s engaging in, similar to the U-tube configuration. Meanwhile, the straight tube design makes cleaning easier, comparable to the fixed tubesheet configuration.
These advantages make floating head shell and tube heat exchangers a favorite among operators who are concerned both about thermal expansion as well as fouling on both sides, such as petroleum refineries or kettle reboilers, for example.
A number of methods can be employed to sanitize floating head shell and tube heat exchangers and remove fouling. Mechanical cleaning is a practical solution, as the straight tubes make it easy for brushes, bits and sprayers to reach all areas of the bores. The floating head configuration makes it easier to remove the tube bundle than with the fixed tubesheet design, so it’s easy to reach the outsides of the tubes and the interior of the shell.
Chemical cleaning is also a possibility, especially because it’s easy to spot inconsistencies in the cleaning job. When insufficiently cleaned areas are identified, they can be mechanically or chemically cleaned again before the equipment is put back into operation.
The bonnet type associated with a particular exchanger’s construction plays a role in how easy this configuration can be cleaned. A P-type rear header, which is an outside packed header, gives convenient access to the tubeside but does not allow the tube bundle to be removed so the shellside can be difficult to clean.
The S-type header also allows the tube bundle to be removed, but it is hard to take apart for bundle pulling, which can cause some complications when it’s being cleaned, inspected or repaired. The T-type header is easier to dismantle and remove than the S-type, often making it a more desirable configuration, though it also tends to be a bit pricier. The W-type header is also easy to remove and is often the least expensive of the options for a floating head heat exchanger.
Proper Cleaning Prevents Fouling
No matter what type of shell and tube heat exchanger you have, it’s important to know how to properly clean it to prevent fouling and ensure deposits left behind won’t cause corrosion.
Currently, the most significant producers of shale oil are Argentina, China, Canada, and the U.S. though others are beginning to take interest. This type of oil, also known as tight oil, is more challenging to retrieve and is extracted using hydraulic fracturing, or fracking.
Customized shell and tube heat exchangers are efficient for processing, but there are important considerations for manufacturers and operators. The refining process is highly prone to fouling, a common and harmful issue, especially with light tight crude oil. Fouling leads to lost production time, increased costs, and reduced profits, as operations must cease for cleaning. Additionally, fouling results in excess energy consumption and decreased throughput. The cost of crude oil fouling in the U.S. is estimated to be around $4.4 billion annually.
Asphaltene precipitation leads to accelerated fouling
Fouling in tight crude oil often results from asphaltene precipitation, which happens when tight oil is blended with other crude types. Refineries typically designed for specific oil compositions can experience bottlenecks with tight oil, especially in naphtha processing and crude overhead units. Blending tight oil with other crudes can mitigate this, but incompatible blends increase asphaltene precipitation. For instance, a blend of 20% tight oil and 80% other oil produces fewer asphaltenes than a 30-70 mixture. Tight oil’s higher naphtha content also accelerates asphaltene precipitation.
Prevent fouling through monitoring
To prevent fouling, manufacturers traditionally inspected machines periodically and recorded information manually. However, with the increased production of tight crude oil, which fouls more quickly, manual note-taking and periodic observation are no longer practical. Instead, using online monitoring capabilities is recommended. Wireless temperature and differential pressure measuring devices can constantly monitor the performance and efficiency of heat exchangers. This allows refiners to schedule maintenance proactively, minimizing the financial impact of downtime. Continuous monitoring also prepares maintenance staff for necessary repairs and indicates if additional parts need to be purchased in advance. Some exchangers have a bypass feature, enabling cleaning without halting production, but for those without this capability, advance knowledge of maintenance needs can reduce turnaround time and mitigate unforeseen obstacles.
Editor’s Note: This content was last updated 3/14/24.
Food processing plants must adhere to stringent standards in handling food products to ensure consumer safety. Various factors, including airborne debris and facility moisture, can lead to the formation of harmful bacteria, ultimately impacting the quality of the end product.
To prevent contamination and cross-contamination in processing facilities, here are five essential tips for maintaining food safety:
1. Keep ramps and carts clean
Sanitation is paramount in ensuring the safety of a food processing facility. It’s crucial to thoroughly clean and dry ramps used for moving carts containing organic and non-organic products. This extends to carts and rampways accessing freezers, as bacteria can remain dormant when food is frozen, necessitating cleaning to eliminate potential bacterial growth.
2. Color code brushes and buckets
To minimize cross-contamination, use color-coded brushes and buckets in food processing facilities. Assign specific colors for cleaning pasteurized food contact surfaces, non-food contact surfaces, surfaces with raw milk products, and floor drains, ensuring consistency across different areas of the plant.
3. Clean all equipment and machinery
Regular cleaning of all equipment and machinery is essential to prevent contamination. This includes refrigeration equipment, HVAC systems, contact surfaces, drains, and heat exchangers. Stainless steel equipment is particularly effective in preventing bacterial contamination due to its durability and ease of cleaning.
4. Ensure workers are healthy
Maintaining the health of workers is crucial in preventing contamination during food handling. Employees should not work while sick or exhibiting symptoms such as vomiting, diarrhea, sore throat, or fever. Proper hygiene practices, including frequent handwashing and wearing clean clothing, further reduce the risk of contamination.
5. Heat products with appropriate equipment
Proper heating of food products is essential in preventing contamination issues. Utilizing the appropriate shell and tube heat exchanger is crucial to achieving the required temperature to eliminate bacteria effectively. Factors such as product type, heating requirements, and production volume should be considered when selecting the appropriate equipment, necessitating consultation with a heat exchanger professional for optimal results.
Ethanol processing plants must ensure their equipment can withstand months of products running through shell and tube heat exchangers. This process builds up dirt and grime on the equipment, which must be cleaned periodically. According to Ethanol Producer Magazine, facilities have to prepare for cleanings in advance to ensure downtime for the process is limited.
Matt Werzyn, maintenance manager for Louis Dreyfus Commodities, Elkhorn Valley Ethanol LLC, explained that ethanol processing facilities must ensure they schedule downtime for the cleaning process, the source reported. The plant managers must follow through with the deep cleanse; otherwise, the facilities will see downtime from grime and dirt buildup.
The cleaning process must be quick and simple. If there are too many steps, the plant could be shut down for multiple days for repairs and equipment maintenance. In addition, certain metals and alloys tend to corrode over time, Engineer’s Edge reported. Finally, some of the chemicals and gases used with heat exchangers in ethanol processing plants can damage the metal.
That’s why investing in stainless steel shell and tube heat exchangers is essential. According to the source, stainless steel is much easier to clean and can withstand multiple cleanings.
Carbon steel is typically used in manufacturing plants but has a somewhat weak passivity, leading to rusting and corrosion. However, stainless steel contains additional alloy elements that increase corrosion resistance and provide more strength over time. This can deliver a quicker return on investment for processing facilities that frequently replace heat exchangers.
Fouled equipment slows plants down
Werzyn added that once equipment becomes fouled or dirtier, there are other consequences for plant operation, Ethanol Producer Magazine reported.
“As we get closer to shut down, there is a definite performance decrease and an increase in the required energies needed to run the process,” said Werzyn. “If duct lines are not cleaned over a long period of time, duct fires can result, which can be very expensive, if not destructive, if they occur.”
Equipment needs regular cleaning to last and perform required duties at its highest level. Werzyn said keeping equipment continuously clean could help save a lot of money in the grand scheme of things, the source stated.
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