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Tag Archive: Brewing Heat Exchangers

  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. Enerquip Testimonial: New Glarus Brewing Company

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    The brewing and beverage industry uses a lot of heat energy, making heat recovery imperative in keeping processes as efficient as possible.

    New Glarus counts on Enerquip for not only a quality product, but for expertise in choosing the best product for their brewing solutions.

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    Why New Glarus Chooses Enerquip
  3. 2 Ways Shell and Tube Heat Exchangers can Reduce Energy in Breweries

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    Fortune
    You can read more [ Here ].

    The craft beer industry has taken off in the last few years. Beer drinkers seek out full, unique flavors and variety in their beverages. Craft beer drinkers also like to support local, small and independently owned breweries.

    Fortune reported that the craft brewers increased volume by 13 percent in 2015, making this the eighth year in a row of growth rates of 10 percent or more. There are more breweries than any beer aficionado can keep track of: 4,269 of them, to be exact.

    Another impressive statistic is that, even in a year when the total beer market for the country contracted by 0.2 percent, the craft beer industry managed to grow, now encompassing 12 percent of the market.

    “The figures show there is still strong growing demand for fuller flavored products from small brewers,” Bart Watson, the Brewers Association’s chief economist, explained to Fortune.

    “It shows the premiumization trend that we’ve seen the last few years has room to run,” he continued, referring to consumers’ willingness to pay higher prices for beer that cost more to produce but have fuller flavor.

    Recognizing obstacles in energy efficiency

    As more craft breweries come on the market or expand, owners and operators are beginning to realize some of the obstacles that can come along with beer production. For instance, breweries are extremely energy-intensive operations. Between refrigeration, space heating, packaging and the actual brew house, there are many aspects to a brewery that require either a large amount of electricity, natural gas or both, the Brewer’s Association explained.

    The Daily Energy Report said many breweries have put efforts into reducing their energy use. Anheuser-Busch InBev announced in 2013 it had reduced its energy consumption by 12 percent and carbon emissions by 16 percent in three years. That same year, $100,000 in grants were awarded to five Wisconsin breweries for their efforts to reduce energy use.

    There are many ways to curb energy consumption in a brewery, as with any other entity. The owner can invest in energy-efficient lighting and Energy Star equipment as two surefire ways to begin conserving, Brewers Association explained.

    Reducing energy in wort cooling

    One piece of equipment many breweries have found various uses for is the shell and tube heat exchanger. These are versatile machines with a wide range of applications in the brewery setting.

    “Shell and tube heat exchangers have a wide range of applications in the brewery setting.”

    A sanitary shell and tube heat exchanger can be used in the brewing process for wort cooling. This is a crucial step, and a shell and tube heat exchanger is a great way to achieve this efficiently. According to Craft Beer & Brewing, a shell and tube heat exchanger can cool the wort to the desired temperature in just 10 minutes, and sometimes even quicker. This not only speeds up the brewing process, but it also results in a clearer product in the end. Shell and tube heat exchangers also use less water than some of their counterparts, such as an immersion chiller.

    Reducing energy in wort boiling

    Prior to the process of cooling the wort, there is a significant amount of energy used to heat up the mixture of water and malt. Chris Riphenburg, head brewer at Madison, Wisconsin-based Ale Asylum, told Craft Brewing Business that it’s essential to have the correct heating source for the kettle or hot liquor tank. There are three options brewers can choose from, though there is one clear choice if the brewer is hoping to reduce energy use and operating expenses. Three options are to use:

    1. A burner, which is an older method not used as often anymore.
    2. A steam jacket, a method adopted by many modern breweries today.
    3. A shell and tube heat exchanger, which can significantly reduce energy costs.

    According to Riphenburg, a shell and tube heat exchanger can be as much as 80 percent more efficient than a burner and 50 percent more efficient than a steam jacket.

    In addition to its environmental and financial benefits, a shell and tube heat exchanger also has the advantage of not having any moving parts and is easier to clean than other heating devices. This means brewers can spend more time making beer and less time worrying about equipment issues.

  4. Enerquip Attends Craft Brewer’s Conference in Philadelphia

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    Brewers Association
    Learn more about this conference [ Here ].

    Craft beer has been a fast growing trend for several years now. According to the National Brewers Association, even as overall beer sales and production dropped 0.2 percent in 2015, craft beer profits went up. Sales of craft beer spiked 12.8 percent while production increased 13 percent.

    Over the past two years alone, various types of craft beer businesses have grown immensely. In 2015, there were:

    • 19,079,780 regional craft breweries
    • 3,927,063 microbreweries
    • 1,281,991 brewpubs
    • 234,181 contract brewing companies

    This represents the addition of more than 7 million regional craft breweries, upwards of 1.5 million microbreweries, more than 300,000 brewpubs and nearly 58,000 contract brewing companies, all in just a two-year time span.

    Celebrating craft brewing

    With so many people dedicating their careers to craft beer and many more becoming enthralled with the trend, it makes sense that industry leaders and budding entrepreneurs alike should come together to discuss all things hops and barley at the upcoming Craft Brewer’s Conference.

    CBC is an annual event that brings brewpubs and packaging breweries together. This year, it will take place from May 3 to 6 in Philadelphia.

    According to Communities Digital News, many locations around the city will be celebrating the craft brewing industry. A wide variety of venues will be showing off their best brews throughout the week. From the National Museum of American Jewish History putting on the Amber Waves art exhibit highlighting the art of brewing to the International Beer Run, there is no shortage of activities for craft beer-loving adults to take part in.

    At the conference

    Despite much of Philadelphia celebrating the CBC, the actual conference’s events are off-limits to anyone not officially in the brewing industry. The first day will offer attendees information about accurately measuring wort gravity and counting yeast cells, while the three following days will give participants a wide variety of educational sessions focusing on everything from brewing operations to sustainability to marketing.

    While each of these points is important, it is crucial that craft brewers know how to produce a safe product that meets all requirements set by the U.S. Food and Drug Administration. Errors can result in distributing a potentially dangerous product.

    When shell and tube heat exchangers are important

    There are many aspects that go into creating an enjoyable craft beer that also meets the requirements set by the FDA. According to the National Brewers Association, all craft brewers must follow Good Manufacturing Practices for Craft Brewers, which include the following guidelines:

    • Using only quality raw materials
    • Maintaining lab tests that can be trusted
    • Establishing standard operating procedures and educating staff about them
    • Recognizing and researching deviations in product quality
    • Creating a good quality management system
    • Packaging and labeling the product according to guidelines
    • Meeting sanitary and processing requirements

    Sanitary shell and tube heat exchangers are important in regards to the last GMPCB. Heat exchangers serve an important purpose in cooling the wort (the early liquid that’s later fermented into beer) to the necessary temperature to begin the actual brewing process, though if they are not properly cared for or graded to meet sanitary requirements, they aren’t worth much to a brewer.

    “All craft brewers must follow Good Manufacturing Practices for Craft Brewers.”

    It’s important that brewers are aware of the standards their equipment needs to meet. This is why conferences like the CBC are so important – they give everyone in the craft brewing industry unique opportunities to learn more about the requirements they must adhere to when brewing.

    Another way shell and tube heat exchangers are used in large-scale operations is for waste heat recovery. This can be applied to operations in a wide variety of industries, but for smaller companies, such as a burgeoning craft brewery, it’s important to keep operational costs low. Energy is expensive, but heating and cooling the product to the right temperature at the right time is crucial to producing a high-quality product.

    The energy required to create heat takes time and money, and without the right waste heat recovery method in place, it is only used once before it is released. Collecting and reusing that heat can make an operation more environmentally friendly as well as more economically sound. Shell and tube heat exchangers are great pieces of equipment to achieve this goal.

    For brewers who know their craft better than anything, but don’t know much about what makes a shell and tube heat exchanger food grade, Enerquip’s in-house engineers can be a big help. This is why Enerquip will be attending the CBC. Anyone involved in craft brewing who wants to know more about how a shell and tube heat exchanger can improve his or her operations, or about what kind of configuration will benefit their operation most, can stop by Enerquip’s table to gain some information.

  5. Shell and tube heat exchangers are used to cool wort in craft brewing

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    Making beer is a complex art. Each process involved needs to be executed precisely for the final product to be of high quality.

    One of these processes is the wort cooling. This stage comes after wort boiling and just before fermentation, which is when the yeast is added to produce alcohol. This sometimes overlooked step is important for several reasons, according to Brew Your Own, a magazine dedicated to home brewing.

    Importance of wort cooling

    Cooling the wort brings the liquid down to a temperature at which the yeast will function best. Ale yeasts flourish in temperatures between 68 and 72 degrees, while lager yeasts prefer temperatures between 45 and 57 degrees. This is a far cry from the high temperatures the wort boils at. According to Beer & Wine Journal, wort boils at above 212 degrees – the exact temperature depends on the liquid’s specific gravity.

    Production of dimethyl sulfide is slowed when the wort is cooled. While DMS is intentionally left in some commercial beers, many beer makers want to eliminate its presence from their brew. It has a tendency to smell like cooked corn.

    “Dimethyl sulfide production is slowed at cooler temperatures.”

    Sometimes wort contains contaminants that affect the taste of the final product. Brewers want to be sure they have bacteria in their wort under control and rapid cooling helps slow any growth. Bacteria can’t reproduce well in high or low temperatures, but once the wort cools below 160 degrees, it flourishes. This is why it’s important to cool it as quickly as possible, to reduce the amount of time the fluid spends in this zone.

    Finally, rapidly cooling the wort will maximize the cold break. According to Brew Like a Pro, the cold break occurs when proteins, tannins and other materials solidify in the wort. The quicker the wort is cooled, the more cold break will form. By increasing the amount that solidify, fewer will be transferred to the the final product. Their presence can make the beer cloudy and affect the taste.

    How to cool wort

    There are several ways to cool wort after it’s been boiled, though some are only efficient for small quantities. For instance, an ice bath might work for a home brewer, but would never be used in a craft or commercial beer setting. A shell and tube heat exchanger, sometimes called a counterflow chiller in the craft beer industry, is widely considered an efficient method for wort cooling.

    The benefit of using a shell and tube heat exchanger rather than other options is how quickly the wort will be cooled. The exchanger can have the wort down to the desired temperature in 10 minutes, according to Craft Beer & Brewing. This is ideal for several reasons. The quicker you can cool the wort, the quicker you can add the yeast and the sooner your brew will be ready. Also, by minimizing the time it takes to cool, DMS will have less time to produce and bacteria won’t be able to multiply as well.

    Comsol pointed out that this method is also an efficient one because the heated water can then be used for the next batch of wort.

    “Maximizing the cold break will make a clearer beer.”

    The cold break will still be in the wort when it goes through the shell and tube heat exchanger. Brewers will be able to clearly see this when the wort that leaves the exchanger is cloudy. The solution to this is to direct the exchanger’s exit to a sanitary vessel and let the cold break settle at the bottom. After this, transfer the liquid to the fermenter and add the yeast.

    Keeping all equipment clean is crucial to craft, commercial and home brewers alike. Fouling can be detrimental to a batch of beer and to a company that sells tainted product. Because of this, brewers must do everything they can to prevent contamination. All equipment should be cleaned properly after use. The shell and tube heat exchanger should be examined periodically to detect any leaks or deformities. Stainless steel shell and tube heat exchangers are easy to clean and more resistant to fouling. To get a quote on an exchanger for your brewing practice, contact Enerquip.

  6. Microbreweries gaining ground in the beer making industry

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    In the last decade, the number of microbreweries filling Americans’ pint glasses has skyrocketed. According to the U.S. Brewers Association, 24% ($22.2 billion) of the beer market belongs to microbreweries.

    With the market growing and competition expanding, breweries have to invest in processing equipment that will bring a return on investment. One of the most common pieces of equipment is a shell and tube heat exchanger.

    When using a heat exchanger where two liquids are involved, the heat exchanger uses heat from one fluid in the shell of the exchanger to warm or cool the other liquid in the tubes of the exchanger.

    The main purpose of this in brewing is to kill the bacteria in yeast, one of the main ingredients in beer. The bacteria in most yeasts in the beer need to be boiled first and cooled afterward. Also, the bacteria is known as thermophilic, meaning it can withstand higher temperatures.

    Having a custom shell and tube heat exchanger allows breweries to reach proper temperatures to kill off the bacteria without damaging the state of the product. According to Serious Eats, there is such a thing as “friendly yeast,” which can be introduced to add numerous flavors while breaking down the sugar.

    Heating these products can kill off the appropriate yeast needed to craft beer. According to Brew Like a Pro, cleaning and sanitation is essential for the “cool side” of the beer-making process because the thermophilic bacteria can multiply and double every 20 minutes.

    The brewing process can be greatly affected by the rolling action of the boil. The heating process needs to be relatively precise, which calls for custom heat exchanger solutions.

    Looking for a heat exchanger solution in your production process? Contact an Enerquip Sales Engineer today.