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Tag Archive: Heat Exchanger Cleaning

  1. Heat Exchanger Material Selection based on Common Criteria

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    With so many factors to consider in choosing a material for your shell and tube heat exchanger, you may have a lot of questions.

    To start, you’ll need to decide which criteria are most critical to your operation. Criteria like thermal efficiency, cost, availability, corrosion resistance, cleanability and durability. You can then weigh the pros and cons of the options that best meet your priorities, since there is typically more than one good alternative. For example, the best material for heat transfer may not be sanitary enough for your application; or the most corrosion-resistant option may far exceed your budget. In most cases, there is a heat exchanger material option that can balance most of your priorities.

    Here are a few tips and suggestions for evaluating the heat exchanger material options based on these common criteria.

    Thermal Efficiency

    Since the goal of a shell and tube heat exchanger is to transfer as much heat as possible between the product (typically in the tubes) and the utility fluid (typically in the shell), the thermal conductivity of the tube material is a key factor. Based on thermal modeling comparisons using HTRI software, copper and copper/nickel are typically the most conductive material available for exchanger tubes. Carbon steel, stainless steel and higher alloys are slightly less efficient, but all perform similarly. Plastics, graphite composites and ceramics are the least conductive materials available.

    Thermal performance can also be enhanced through modification to tubes, such as corrugating, adding external fins to the tubes, or by adding twisted tape turbulators to the inside of the tubes. However, because thermal performance among metals is so similar, this is not usually a high priority factor in heat exchanger material selection.

    Cost & Availability

    Material pricing and availability can fluctuate based on market supply and demand, the quantity required for your exchanger, and the components needed. Copper was a low-cost option a few years ago, but now due to supply, it is more expensive than stainless steel. Conversely, Titanium used to be one of the most expensive alloys but is now more reasonably priced. At the time of this article, here is the relative ranking for some of the common metal material options by price from lowest to highest: carbon steel, 304/304L SS, 316L SS, Duplex 2205, Titanium, AL6XN, Duplex 2507, Hastelloy C-276, Hastelloy C22, Monel 400, Alloy 625, and Nickel 200.

    Typically, the higher priced alloys are also in shorter supply, due to lower demand and the higher cost of carrying inventory. This directly affects the lead-time of these materials, often by 2-4 times that of more common alloys like carbon steel and stainless steel. Quantity of these higher alloys can also greatly affect price. Steel mills typically don’t run small batches of tubes or plate or they will charge for the entire mill run if they do.

    Enerquip Bundle

    U-tube water cooler built with 2205 Duplex tubes – an austenitic-ferritic stainless steel that stands up to chloride stress corrosion.

    Shell Side and Tube Side May Be a Combination of Materials

    The shell side and tube side of an exchanger can be built from different materials of construction. It is common to use a more corrosion-resistant and/or sanitary alloy for the product side of the unit, while using a lower grade alloy for the utility side of the exchanger.

    If a higher alloy is the material selection, it is more economical to use it on the tube side of the unit instead of the shell side. However, be aware that for tubing, seamless tubes are almost double the price of welded type tubes, so this should be considered as well. You may find that seamless 316L stainless tubes cost more than welded Duplex 2205 tubes, for example.

    Common parts such as fittings are less likely to fluctuate than raw materials like plate stock, tubing and forgings. There are ways to help reduce cost when using higher alloy components. Consider lap-joint flanges, where the product contact nozzle (stub end) is high alloy, while the flange is stainless or carbon steel. These also aid in ease of installation, ensuring bolting alignment with existing, mating piping or equipment. Larger parts like tubesheets, flange rings and channel covers can often be made from a lower alloy base material that is clad with a thinner layer of high alloy to reduce cost.

    Supplier Resources

    Another factor to consider when evaluating the various alloys is the number of suppliers that work with these materials, since this can affect cost and delivery. There are many fabricators that build exchangers from carbon steel and copper, so competition is high, prices are low, and lead-times are generally fast. There are fewer suppliers that work with the alloys from 304/304L SS up through the Incoloy series, but enough to keep prices and lead-times reasonable. Fabricators must have ASME compliant weld procedures for these alloys to provide pressure vessels such as shell and tube exchangers, which are classified as National Board Registered pressure vessels. Not all fabricators have these procedures for all materials, so it is wise to verify your preferred fabricator’s capabilities when considering alloy options. Since Titanium, Zirconium and Tantalum require specifically controlled environments for fabrication, supplier options are more limited. This specialty niche can be expensive with longer lead-times, so these materials are normally only used when applications require nothing less.

    Dispelling the carbon steel is cheaper myth: For most small and mid-sized exchangers up to 24 inches in diameter, it can be less expensive to upgrade carbon steel shells to a material selection of 304 stainless steel. Although the material cost is a bit higher for the stainless per foot, stainless eliminates the labor cost for priming and painting the exterior, which typically offsets the material cost difference. This, combined with reduced maintenance costs and added durability, makes stainless a better long-term value.

    Corrosion Resistance

    If corrosion resistance is critical for your application, it is best to consult a metallurgist to discuss the operating conditions and request their recommendation. Most reputable high alloy providers have metallurgists on staff. Rolled Alloys has proven to be a good resource, with responses and recommendations provided within 24 hours. Corrosion resistance charts can also be helpful for less critical applications where corrosive element concentrations are low.

    Many people are not aware that carbon steel is not only corrosive itself but can cross-contaminate stainless and higher alloys and cause them to rust. That is why it is not a good idea to use regular steel wool to clean your stainless sinks and silverware, as it will cause rouging. The same affect can be seen in heat exchangers containing carbon steel parts. Rust from carbon steel parts will attack the higher alloy parts of your equipment, potential causing premature failure. However, there are also cases where carbon steel offers better resistance to stress corrosion cracking than stainless steel, so the risks of rust corrosion need to be weighed against stress corrosion cracking during material selection.

    Copper and CuNi have moderate corrosion resistance but tend to discolor and scale easily. These softer materials are commonly used for shell and tube exchangers in utility applications, where the non-sanitary tube material and carbon steel shells do not create a product contamination issue.

    Stainless steel has become a very common heat exchanger material selection for low to moderate corrosion resistant applications. Since 316L SS is more corrosion-resistant than 304L SS, it is often selected for the tube side of an exchanger, while the shell is made from 304L SS. If additional corrosion resistance is needed, then the Duplex stainless series (2101, 2205, or 2507) is considered. Continuing up the ladder of corrosion resistance AL6XN is followed by Hastelloy alloys C-276, C22 and C2000. For higher corrosion resistance, Monel 400 and Alloy 625 are considered, before evaluating the extreme corrosion resistance of Titanium, Zirconium and Tantalum. Note: Each alloy has a specific resistance level to specific chemicals or solutions, so it is best to consult with a metallurgist during the selection process to match your process with the proper material.

    Enerquip wiped film evaporators

    This custom pair of wiped film evaporators were built for a hemp processing application. Their 304L stainless steel straight tubes were bright annealed to reduce surface oxidation.

    Cleanability

    If ease of maintenance and integrity of your product quality are high priorities, then materials that are easier to clean and maintain should be selected. The materials must stand up to your preferred cleaning regimen – whether it be chemical, mechanical or ultrasonic cleaning (or a combination). Acids, caustics and chlorides are common in cleaning solutions, but can be harmful to metals in higher concentrations or elevated temperatures. Once you decide on a material of construction, companies that provide these cleaning chemicals, like Ecolab or AFCO, can provide recommendations on concentrations that are suitable.

    Sanitary Markets Require Stainless

    In sanitary industries such as food, beverage, dairy, pharmaceutical and cannabis processing, product contact surfaces must be stainless steel or a higher alloy, and cleanable, to comply with strict guidelines such as FDA, ASME BPE or the 3-A Sanitary Standards. Because the surface finish of the material impacts its cleanability, these industries require product contact surfaces to be polished to a specific Ra (roughness average) for food, beverage and dairy, and for pharmaceutical applications. Some pharma applications also require electropolishing, which removes a very thin layer of material, aiding cleanability further. Smoother material surfaces also resist build-up and scaling on both the product and utility side of an exchanger. Therefore, many companies avoid carbon steel and copper, which can become more porous as they corrode, encouraging scaling and fouling.

    Durability

    For situations where durability is not a high priority, low cost, catalog type heat exchangers constructed from copper and carbon steel may be appropriate. Many HVAC applications fall into this category, where replacing parts from time to time is normal and acceptable. However, in production facilities, where process equipment is pushed to its limits on an ongoing basis, durability is much more critical. Equipment failures can contaminate product, stop production and even be dangerous.

    It is important that the material selected for your heat exchanger meets ASME Code requirements and can operate for an extended time at your operation’s design pressures and temperatures. The materials must withstand your cleaning regimen and environmental factors such as moisture, dust, and temperature extremes.

    In situations where dissolved solids and high tube velocities can take their toll on heat exchanger parts, it makes sense to use materials that are erosion resistant. When carbon steel and copper exchangers are designed, ASME Code requires a corrosion allowance be added to the material thickness. This is added to account for anticipated corrosion and loss of material thickness over time. These exchangers may also include anodes that corrode away before the exchanger parts do. These can be monitored and replaced periodically. When higher alloys are used in place of carbon steel and copper, these corrosion allowances are no longer required, resulting in thinner, lighter materials in a more durable piece of equipment. Stainless and higher alloys do not require painting to protect their exterior finish from corrosion, so there is no flaking and peeling paint to contend with, decreasing maintenance time and expense.

    The experts at Enerquip are happy to assist you by providing options for your shell and tube heat exchanger materials of construction. Since they work in many alloys, they can provide suggestions and feedback to help you narrow down your choices based on your priorities. For more unique cases, they will refer you to credible metallurgists who can help you finalize your heat exchanger material selection.

    Click here to learn more about Enerquip’s custom exchangers.

    Article Author: Ron Herman, Director of Business Development

    Ron Herman, Enerquip Director of Business Development

  2. Chiller Tube Maintenance Step-by-Step Guide

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    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.

  3. Tips for preventing food recalls from your production facility

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    Sanitary

    How do you prevent food recalls? Shoppers trust that, when they put groceries into their carts and bring them home to eat, the food they’re buying is safe. As a food production company, it’s your responsibility to ensure the products you ship out from your facility are in good condition and safe for consumers.

    A few aspects of this are ensuring your process is designed to prevent and detect potential contamination, and that your equipment is adequate for the job and thoroughly cleaned.

    Prevent Food Recalls: Why is it Important?

    Mistakes can happen. Food products are recalled on a regular basis. Often, recalls have to do with undeclared allergens. Other times, contamination can lead to a dangerous situation that prompts a recall. Some of the most common foodborne illness-causing organisms include:

    • E. coli.
    • Listeria monocytogenes.
    • Salmonella.

    These organisms can cause severe illness or even death, and may be found in food or dairy products that aren’t properly prepared. An estimated 1 in 6 Americans contract a foodborne illness annually, according to the U.S. Food and Drug Administration.

    It’s always important for companies to actively work to prevent food recalls, reduce the risk of food contamination, and report dangerous products as soon as they’re discovered.

    Food recalls are not only dangerous to consumers, but can also cost a business time, money and reputation. The average cost of a single product recall is $10 million, according to a study from The Grocery Manufacturers Association, Food Marketing Institute, Deloitte and GS1 US. That’s before lost sales and brand damage are taken into account.

    Prevent Food Recalls through Process Review

    If your process doesn’t support sanitary food production, you’ll always be at risk of a contamination. Since the FDA Food Safety Modernization Act came into effect, all companies who work with food products have completed a thorough process and equipment review and made any necessary changes where the operation put product at risk of contamination.

    Reviewing your process shouldn’t be a one-time task. It’s important to periodically review your systems and identify potential areas to improve. Conduct a vulnerability assessment, Global Food Safety Resource recommended. This can show you areas where your operations are most at risk.

    Regular inspections should be carried out, even during busy periods. During fast-paced production times, inspections may consist of simple visual reviews, which is fine in the short term. However, it’s important to follow these less detailed inspections with a more in-depth analysis later on.

    Investing in Sanitary Equipment

    The equipment you use plays a key role in product safety. There are two major factors that contribute to sanitary equipment: the features of the equipment itself (including materials and construction), and the continued maintenance and cleaning of them.

    Some basic sanitary equipment design principles include having smooth surfaces and rounded edges so product doesn’t get stuck in sharp corners, Food Quality and Safety noted. Equipment that’s easy to clean is also important.

    Stainless steel shell and tube heat exchangers meet these requirements. Straight tube designs have virtually no corners where product can get trapped and foul, and they’re simple to clean. U-tube models are a little bit trickier, but the rounded bend can be cleaned with the right process and equipment. Stainless steel in particular is a sanitary material because it’s resistant to contamination and fouling and is easy to clean.

    Cleaning in Place is a technique that allows for thorough cleaning without disassembling equipment or wasted water. CIP systems use shell and tube heat exchangers to run water, steam and/or cleaning chemicals through the equipment, recycling the liquid when it’s complete. CIP is both an effective and environmentally friendly way to keep equipment clean.

    Choosing a Sanitary Shell and Tube Heat Exchanger

    Just like it’s important to note the quality of standards of your food vendors, it’s equally critical to work with an equipment supplier that can be trusted to provide high-quality sanitary equipment. Your process is only as safe as your equipment allows.

    Cross-contamination is a common concern in food processing facilities, but it’s also possible for your equipment to be affected by cross-contamination if it comes into contact with materials that aren’t meant to be food grade, such as carbon steel. Enerquip takes cross-contamination concerns seriously, which is why their engineers don’t work with carbon steel. Additionally, your equipment can be constructed according to 3-A requirements and other sanitary regulations.

    Enerquip’s heat exchanger surfaces that will come in contact with products have surface finishes of 32Ra, though they can provide higher polished or electro-polished surfaces for hygienic applications.

    To learn more about Enerquip’s custom shell and tube heat exchanger design process, reach out to our helpful heat exchange experts. We’ll talk through your process and determine your unique needs to provide you the best unit for your company, to help you prevent food recalls and product contamination.

  4. How often should you clean your shell and tube heat exchanger?

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    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.

  5. Preventing Cross Contamination in Your shell and tube heat exchangers

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    Cross contamination is a shared concern at all stages of the food industry. Chefs need to make sure their fresh veggies are kept away from their raw meat; storage facilities strive to keep common allergenic foods like nuts separate from other ingredients; and food production plants must ensure products sent through their process equipment isn’t affected by harmful bacteria, chemicals or other items.

    Shell and tube heat exchangers are popular in food production plants as a method to pasteurize fruit, vegetable or dairy products, or to achieve a desirable consistency, as in honey or maple syrup production. Cross contamination is also a risk factor in industries like pharmaceuticals and personal care.

    It’s important that these important pieces of equipment don’t contribute to any form of cross contamination. If this were to occur, it could reduce plant efficiency, lead to a ruined batch of product or necessitate a recall. There are many different ways to reduce the chances of cross contamination in your food or pharmaceutical production facility. Here are a few:

    Work with quality equipment fabricators

    The materials used in the construction of your shell and tube heat exchangers play an important role in the quality, sanitation, cleaning requirements and lifespan of your equipment. Many food industry companies turn to stainless steel for its fouling resistance.

    Choosing a stainless steel shell and tube heat exchanger is therefore a good step toward preventing cross contamination in your facility. However, you can take this one step further by finding out what sort of environment in which your shell and tube heat exchanger is fabricated.

    Cross contamination isn’t just limited to food items; you can also cross-contaminate metals. As such, it’s worthwhile to find out if your stainless steel shell and tube heat exchanger is being made in a facility that also utilizes carbon steel. If it is, there’s always a chance that this metal, which is more prone to fouling, can contaminate your equipment.

    At Enerquip, we value the integrity of stainless steel, which is why we don’t work with carbon steel. When you receive one of our heat exchangers, you can feel confident that it hasn’t been affected by this metal.

    Strategically choose your tubes

    When cross contamination does occur in a shell and tube heat exchanger, it may be caused by the shell-side fluid mixing with the tube-side fluid. To prevent this from happening, added barriers or an adjusted tube design can help.

    Enerquip’s high purity shell and tube heat exchangers are fitted with double tubesheets, which reduces the risk of cross contamination of this type. These custom and standard pharma-grade exchangers are particularly useful for pharmaceutical, nutraceutical, animal health and personal care industries.

    Double tube sheet configurations typically have a form of leak detection installed in the exchanger. If a leak were to occur in these models, the fluid should drain away from the exchanger and into a safety container rather than mixing with the other fluid, and alerts the operator that there is an issue to repair.

    Understand pressure differentials

    The engineers who create shell and tube heat exchangers must understand many complex formulas to know how the equipment will behave once it’s put to use. The pressure differential, or the difference between the pressures inside the exchanger, is an important one that relates to the likelihood of cross contamination. Typically, the pressure on the shellside would be less than inside the tubes. That way, if a leak springs, the product will flow into the heat transfer medium, rather than the medium mixing into the product and entering the tubes. This helps to keep the negative effects of a cross contamination incident as low as possible.

    Regular inspections and cleaning

    If there’s a chance of cross contamination in your equipment, it’s best to know sooner than later. Periodic visual inspections is the first step in identifying weak points and emerging problems that could lead to contamination, Business Standard pointed out. In your inspections, you might see early signs of leaks in your tubesheet or gaskets. If you catch this early, you may be able to replace or repair the damage before it leads to mixing fluids.

    You may also see early signs of fouling. If fouling is allowed to continue for too long, it can lead to spoiled product. If you do, you’ll want to clean the exchanger and determine whether you can make any changes to your process to prevent fouling. This might mean exploring new options for heat transfer fluids, cleaning more frequently or changing your sanitation methods.

    Whether you’ve experienced cross contamination at your facility or simply want to ensure you’re doing everything you can to prevent it, strategically choosing your shell and tube heat exchanger and making sure it’s kept in good condition can go a long way to help your efforts. To learn about Enerquip’s stainless steel shell and tube heat exchangers, reach out to our knowledgeable engineers.

  6. What you need to know about cleaning different tube configurations

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    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 fixed tubesheet shell and tube heat exchangers

    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.

    “Shellside cleaning is a bit more complicated with fixed tubesheet designs.”

    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.

    “The bonnet type plays a role in how easy a heat exchanger can be cleaned.”

    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.

    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. To learn about the right configuration for your operation, reach out to the helpful engineers at Enerquip

  7. Heat Exchanger Routine Maintenance Tips

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    How do you tackle your shell and tube heat exchanger routine maintenance? When heat exchangers are an essential aspect of your operation, it’s important that they’re working at top efficiency. Dirty or fouled exchangers can slow down your processes, contaminate your product and lower your company’s overall efficiency. To avoid these negative consequences, it’s important to be vigilant about shell and tube heat exchanger routine maintenance and proper cleaning.

    Here are five factors to keep in mind to make your shell and tube heat exchanger routine maintenance as effective as possible:

    1. Create a Plan for your Heat Exchanger Routine Maintenance

    When it’s time to clean your shell and tube heat exchanger, there’s a good chance that you’ll need to shut down operations temporarily. This is lost production time, which translates to reduced output and efficiency. However, there are ways to minimize the effects of a plant shutdown. One of the most effective ways to lower the impact is to prepare for it.

    Have a dedicated datefor planned maintenance, Ethanol Producer Magazine suggested. This way, you can plan and prepare for the event, allowing you to choose an inconsequential day for the shutdown. Additionally, since contractors who specialize in equipment maintenance often have busy schedules, planning and preparing can help you choose the date and time that suits you best – not when the contractor has a free space in his schedule.

    Make sure that any spare gaskets or replacement tube bundles are ordered in plenty of time to arrive by your scheduled maintenance date. Without a predetermined date for planned maintenance, it’s all too easy to let this important task get pushed back. When this happens, your equipment is more likely to run into problems. Sooner or later, you’ll either have to shut down your operation yourself, or a piece of equipment will fail, and you’ll have to quickly schedule reactive maintenance. There’s no predicting if or when this will occur, and it may not always be in your favor.

    2. Inspect Your Equipment

    Excessive fouling is never a good thing for your heat exchanger. If not identified or addressed in a timely manner, it could result in several problems, including contaminated or unusable product, corrosion or leaks. Ethanol Producer Magazine pointed out that, in some cases, material buildup can become a fire hazard.

    To prevent these issues, it’s important to note when fouling begins to form and to remove it promptly. Check your tube bundles as well as the shell side for signs of material buildup or corrosion.

    3. Test your Heat Transfer Fluid

    Another area of concern is the heat transfer fluid. When using chemical-based HTFs, it’s inevitable that the material will eventually become degraded and less effective. When this happens, it can reduce the efficiency of the exchanger and, depending on the chosen fluid, can adhere to the surface of the tubes, become a more volatile solution or create a fire hazard, Processing Magazine reported.

    Regularly testing the HTF will tell operators where in the lifespan the fluid is. Take the fluid from several different places to get a more complete idea of how good the fluid still is. Additionally, be sure to test the fluid while it’s in operation; cooled HTF will display different properties than the HTF in action, making the reading of fluid from a shutdown machine a less informative sample. Additionally, shutting down a piece of equipment for the purpose of taking a sample will slow down operations, put undue stress on the equipment and HTF, and takes more time out of your workday.

    Test the fluid periodically; Processing Magazine noted that quarterly testing typically provides the best results.

    4. Collaborate with the Right People

    Shell and tube heat exchanger routine maintenance is no small task, so it’s important to include any and all relevant personnel in planning it. Work together to identify maintenance needs, a day that works best for the company and the right professionals to assist or carry out the job.

    “Approach your planned maintenance day with a checklist.”

    “The maintenance manager, the environmental health and safety coordinator, and I typically work together on scheduling and making sure we have the proper documentation, training records, etc.,” Tyler Edmundson, the plant manager at ethanol plant Mid-Missouri Energy, told Ethanol Producer Magazine. “Safety is the No. 1 priority – making sure contractors have proper credentials and understand our policies and expectations.”

    When you include people from different departments, such as your environmental health and safety team, you’ll be able to collaborate on smart decisions that are good for the company overall. Additionally, when you approach your planned maintenance day with a checklist, you’re more likely to have as productive a shutdown day as possible.

    Edmundson noted that working with different people to plan out the maintenance day also allows them to collect all the necessary documentation that any incoming professional would need to know. For example, Matt Werzyn, maintenance manager with Louis Dreyfus Commodities, Elkhorn Valley Ethanol LLC, told Ethanol Producer Magazine that he creates and sends an informational packet to any contractors that will work on their equipment. It includes the company’s safety rules and requests items from the contractor, like employee training records, to demonstrate their credentials. Then, after arriving on-site, but before they get their hands on the equipment, the team goes through a contractor orientation.

    Other information you may want to provide any contractor that will be working with your equipment is a maintenance log, documentation from the original equipment manufacturer or information about the products or fluids used in the equipment.

    5. Cleanup after your Heat Exchanger Routine Maintenance

    Depending on your cleaning method, there may still be necessary tasks to carry out once everything is all cleaned. Whether you used chemical or mechanical cleaners to remove fouling, there could be debris left over. This could contaminate your product if left unaddressed. Give your equipment a rinse to ensure there are no leftover chemicals or dirt.

    Your shell and tube heat exchanger is designed to be closed up tight most of the time. As such, opening it can sometimes cause damage to the gasket, Marine Insight explained. Be sure to double-check your gasket and gasket cover before wrapping up your heat exchanger maintenance. Make sure that you have spare gaskets on hand and replace them if necessary.

    Heat exchanger routine maintenance and cleaning can be a time-consuming task, but it’s not one that’s worth putting off. By being proactive, you can help your equipment perform more efficiently and last longer. When you have questions about proper care for your heat exchanger, need replacement parts, or when you’re ready for a replacement unit, reach out to the helpful heat exchanger experts at Enerquip. Clickhere to contact us today.

  8. New FSMA Guidelines for cGMP’s

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    According to the Centers for Disease Control and Prevention (CDC), about 48 million people in the U.S. (1 in 6) get sick, 128,000 are hospitalized, and 3,000 die each year from foodborne diseases. This is a significant public health burden that is largely preventable.

    In 2015, the FDA Food Safety Modernization Act (FSMA) was enacted to help prevent foodborne illness rather than simply responding to it. FDA has seven major rules in regards to FSMA for both human and animal food. The FSMA rules are designed to make clear specific actions to prevent contamination.

    CGMPs for animal food

    CGMPs for animal food production cover elements like personnel, sanitation, work environment, water quality, equipment and more. Jenny Murphy, a consumer safety officer at FDA’s Center for Veterinary Medicine, explained that CGMPs are typically actions manufacturers should already be making throughout the normal course of their business.

    “I would say the CGMPs establish a base to make sure you don’t contaminate the animal food and the preventive controls take it a step further by making you really concentrate on things that, if they’re found in animal food, could be a public health concern,” Murphy said, according to the Food & Drug Administration.

    For example, according to CGMPs, equipment used for food manufacture should be:

    • Adequately cleanable.
    • Made from nontoxic materials.
    • Properly maintained.
    • Protected against contamination.

    Preventative controls for animal food

    While CGMPs cover the basics of maintaining a sanitary work environment and can be applied to any facility, preventative controls are more individualized to unique plants and are designed to address more specific situations.

    “Preventative controls are more individualized to unique plants.”

    “Once you have CGMPs in place, you can see where you need extra layers of protection,” Murphy explained. “Preventive controls require a food safety plan that includes an analysis of potential biological, chemical or physical hazards and the steps needed to reduce or minimize that risk.”

    Joann Givens, the director of FDA’s Food and Feed Program in the Office of Regulatory Affairs and a co-chair of the FSMA Operations Team Steering Committee, explained that it’s OK – even advisable – to have some redundant processes in place. This way, when one procedure falls short, another can pick up the slack. It ensures all your bases are covered.

    Givens explained that preventative controls are important because, if a violation does occur, some of the first questions a facility manager might be asked include:

    • Could you have predicted this issue?
    • What did you do to prevent it?
    • Once it became a problem, what did you do?
    • Did you educate your employees about the issue or how to address it?

    Every animal food manufacturing plant will have different risks, and therefore each may have different preventative control requirements. Facilities should have preventative controls in place for:

    • Processes, like heating or refrigerating.
    • Sanitation, like the minimization of pathogens or biological hazards.
    • Supply chain.
    • Recalls, when they’re needed.
    • Any other aspects of the facility where a preventative control might make sense, such as hygiene training or reviews of CGMPs.

    Making sure your equipment is compliant

    Your process equipment is a large investment, which means you’ll want to make sure it’s compliant from the get-go.

    Stainless steel shell and tube heat exchangers are a common component to animal food manufacturing facilities because they meet many CGMP expectations. For example, stainless steel is a highly sanitary surface, which meets the requirement that materials that come in contact with the product should be nontoxic.

    Certain configurations also allow for easy cleaning. Tube bundles on u-tube exchangers are often easier to remove, giving easy access to the crevices of the exchanger when cleaning. On the other hand, straight-tube designs don’t have difficult curves to work around when cleaning.

    It’s also important to think about the wear and tear equipment sustains over time. Shell and tube heat exchanger processes that involve high-pressure differentials can create more stress on the tubes and tubesheet, making a leak or other form of damage more likely. When a tube springs a leak, the batch of product inside the equipment could become contaminated. This is especially true if the feedwater used is of lower quality than required for animal food production. The U.S. Food & Drug Administration pointed out that this is often the case, which means facility managers must always be aware of the state of their equipment.

    The first step in preventing leaks in exchangers – and thus fulfilling CGMPs relating to avoiding contamination – is to regularly inspect the equipment and identify when a problem emerges. Seeing the signs of wear and potential leakage should be enough to pursue repair or replacement of the weathered part or the piece of machinery as a whole.

    Understanding the many requirements included in the FSMA isn’t always easy, but it’s important that animal food manufacturers determine where their current weaknesses are and address them sooner rather than later. Murphy explained that the FDA won’t begin conducting inspections to make sure everything is up to code until 2018, but that doesn’t mean there’s time to waste.

    For animal food companies looking to upgrade their equipment in compliance with current CGMPs, the engineers at Enerquip can help.

  9. How to close out sugaring season on a sweet note

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    Warm weather and budding trees are clear signs the maple sugaring season is over. With nights failing to fall below freezing, the sap flow slows down. And, as the leaves begins to bud, they spur a chemical change within the tree, making the sap that continues to seep through the spiles bitter, Michigan State University Extension explained. As such, this is the time of year when maple syrup producers begin to pack up their operations and wind down for the season.

    To make sure your maple syrup operation has another great year next spring, it’s important to perform a few housekeeping tasks before the end of the season.

    1. Inspect all your equipment

    While pure maple syrup is a natural food, with its only ingredient readily available in the trunks of trees, the equipment involved is intrinsic to its production. Spiles and buckets, or a system of tubing, are necessary for collecting the sap; pans and heat sources are needed to remove gallons of excess water; and shell and tube heat exchangers are essential to achieve a desirable consistency and kill off and remove bacteria and bugs.

    At the end of sugaring season, don’t put away any equipment without a thorough inspection. Now is the time to replace any cracked, warped or rusted pieces. That way, you’ll be ready to go when the weather begins to warm up next year.

    2. Review your tappable trees

    The first step in producing high-quality maple syrup is tapping excellent trees. Take a careful walk through your sugar bush to identify any dead, diseased or damaged trees, the University of Massachusetts Extension suggested. Look closely to determine whether any trees are infested with insects. Finally, pay attention to the quality of sap each tree produces. If certain trees are producing smaller amounts of sap, or sap with an off taste, it might be time to retire them. Once you’ve determined which trees are no longer serving your operation, cut them down. Clearing your sugar bush of these trees will make room for young, healthy trees to grow faster.

    3. Keep everything clean

    The maple syrup production process is an incredibly sticky one. Starting with the sap, through the evaporation to the final pasteurization and then bottling, every piece of equipment involved in the process is susceptible to becoming coated with sugar. Additionally, since the product is procured and typically prepared outdoors, there’s always a chance of dirt, debris and bugs getting stuck to equipment. To ensure your equipment stays in top condition, and to set the stage for high-quality syrup next year, it’s important to remove the sticky ooze as well as any insects or debris. Hot water is the key ingredient for much of your cleaning work, since detergents and soaps will leave behind unwanted flavors that will inevitably make their way into next year’s batch. If you do want to use a product to further sanitize equipment, it’s best to refer to the manufacturer for advice, Pennsylvania State University Extension advised. The end of maple syrup season can be bittersweet. Once the sap flow begins to trickle to a stop and the buds come out, you know that you’ve collected all the sap you can this season. Now, you have a summer of selling delicious pure maple syrup ahead of you.

    If you find that at the end of sugaring season, you’re ready for new equipment or have questions about how to care for your shell and tube heat exchangers, reach out to the helpful heat transfer engineers at Enerquip.

  10. Davit Arm Assemblies

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    Heat exchanger expert, Ron, explains how to make your shell and tube heat exchangers more user friendly for your maintenance crew down the road.

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    DAVIT ARM ASSEMBLIES