In part one of our two-part column on compressors for carbon capture and storage, we discussed the applications and design of reciprocating versus centrifugal compressors for a sustainable energy economy. For lower-flow carbon sequestration applications, reciprocating compressors have been the traditional base option over centrifugal compressors. In many cases, electric motor-driven reciprocating compressors are utilized. However, as the industry is rapidly moving toward much higher CO

 volume flow rates for large-scale carbon capture, the limits of the practical use of reciprocating compressors are being reached. We conclude our discussion on this topic with a look at compression challenges and the often overlooked, lesser-known disadvantages of reciprocating compressors for CO

 is generally considered a heavy gas with a molecular weight twice that of natural gas and 22 times that of hydrogen. As noted, this makes CO

 from a simple thermodynamic perspective, relatively easy to compress, but it presents other technical challenges that need to be addressed to make the overall compression or pumping process efficient and reliable.

For most carbon-capture applications, the compression process must cross the critical point of CO

 from the gas phase to either the liquid or supercritical dense phase. Therefore, it has strong thermodynamic path dependence and multi-phase behavior. Its physical properties vary considerably during the phase transitions, which makes aerodynamic design challenging.

 is a heavy gas, which results in amplified dynamic forces on any moving components. It has significant volume reduction and temperature increase with work input that results in the need for a wide range of flow coefficient stages (for centrifugal compressors), cylinder sizes (for reciprocating compressors), and multiple intercoolers. 

Carbonic acid is formed in the presence of water, which corrodes metal. At high pressures, CO

 also selectively leeches certain elements from common metals. 

 is soluble in elastomeric materials, which can lead to rapid decompression failures. Also, when rapidly expanded, CO

 quickly forms liquids and dry ice, which can become a problem by plugging dynamic and static seals.

Aerodynamic concerns come from its low sonic speed, which can result in high Mach numbers, causing shock losses and a reduced operating range. It also has a very low viscosity, which, while being beneficial from a pressure-drop perspective, can result in earlier boundary layer separation and increased secondary flows.

These issues apply to both centrifugal and reciprocating compressors, but reciprocating compressors have additional issues when operating with CO

. Some of the top challenges are pulsation control, leakage, flow control, and mechanical reliability.

Reciprocating compressors produce pressure pulsations that are induced into the piping system. These pulsations can cause acoustic resonance and mechanical vibration if they are not properly attenuated. This is especially true for dense gases, such as CO

, that amplify dynamic forces and are capable of transmitting pulsations over very long distances. Complex attenuation systems, including bottles, choke tubes, side branch absorbers, and orifices, are usually required to control these pulsations. Due to the low sonic speed and the high density of CO

, the reciprocating compression process injects strong periodic pulsations that result in high-amplitude acoustic resonances at low frequencies in the piping systems of the compressor station. 

Not only can these pulsations induce strong structural vibrations resulting in piping failures at these stations, but they can also travel miles down the pipeline causing noise and structural issues. It is therefore imperative to design the compressor stations with appropriate pulsation attenuation devices and resonance avoidance to eliminate the possibility of developing strong pulsations in the flow.

 creates several challenges, including a higher risk of pulsation and vibration problems than typical natural gas transmission stations. Current existing CO

 pipelines operate above the critical point between 1,200 - 2,200 psia to maintain single-phase operations in the dense-phase region. With a typical pipeline pressure of 2,100 psia at ambient temperatures, the associated density is around 60 lb/ft

, which is nearly equal to that of liquid water. Since density directly correlates to pulsation forces, this can cause significant issues with pulsations and shaking forces if the reciprocating compressor pulsations are not adequately attenuated. 

The other challenge to consider in compressing CO

 is its relatively low speed of sound. Acoustic natural frequencies in the piping system are determined by the speed of sound of the medium. Low speed of sound results in low acoustic natural frequencies in the system. When a resonance condition is created at low frequencies, the resulting pulsations can travel for long distances in the piping with lower attenuation than what is typically seen in higher-frequency pulsations and with lighter fluids. Pulsations traveling over hundreds of miles upstream or downstream have been observed in dense gases. Low-frequency excitations can also result in a strong structural interaction that has the potential to cause severe damage to the piping system, even at piping locations far away from the pulsation source.

Leakage control in reciprocating compressors is very difficult, especially over time as the sealing rings and packings degrade. Current packing technology uses a series of specific cut-dry ring seals held in place with springs and cups to seal the pressurized gas in the cylinder against the air at atmospheric pressure in the distance piece. Abradable packing seals made from polymers are commonly used to minimize leakage. These tend to wear over time, so leakage can become excessive unless they are frequently changed. Once the piston moves, the pressure differential across the packing seals creates a twisting effect on the seal, allowing significant amounts of process gas to leak into the casing and then out into the atmosphere. The leakage through this pathway increases even more with wear and increases (sometimes exponentially) with static hold conditions since the seals are primarily designed to activate with a moving piston rod. This is obviously very problematic for carbon-capture applications since the primary objective of the system is to capture and sequester as much CO

 as possible...not to leak it. As noted, when CO

 is leaked and/or rapidly expanded, it can form dry ice due to the Joule-Thomson effect, which can cause significant operational problems. Reciprocating compressors could easily become a major source of CO

 emissions from leakage. From a design perspective, it is difficult to completely eliminate a gas leakage path from the process gas cylinder to the piston rod. 

FLOW CONTROL, RELIABILITY, NOISE, AND LUBRICATION

Some other concerns with reciprocating compressor operation are flow control, reliability, noise, and lubrication. Flow control is challenging in reciprocating compressors since they are fixed-volume displacement machines that typically only operate over a limited speed range because of pulsation and vibration limits and exclusions. Flow control is usually handled using variable cylinder clearance volume, external pockets, and recycling. This not only means added operations personnel for mostly manual control, but also that with a reciprocating the operation of the pipeline is usually transient in that one is constantly packing and unpacking the line.

Reciprocating compressors are mechanically less reliable and require more maintenance than most other compressor types. This is due to their many moving parts and high-speed alternating linear motion that puts inertial cyclic stresses on most reciprocating parts. In a power plant, where operational uptime, high start-up reliability, and low maintenance costs are imperative to remain profitable, this is especially problematic. 

Reciprocating compressors create high levels of sound in a frequency range that is a major noise nuisance and very uncomfortable to human hearing. Unfortunately, because of the bulkiness and mechanical arrangement of these compressors with external moving parts, effective ambient noise control using sound-insulating blankets or enclosures is difficult. 

Finally, most reciprocating compressors operate using wet seals, which means that they continuously leak lubricating oil into the process gas stream from the lubricating film between the cylinder and pistons. Even with a well-controlled lubrication make-up system and an efficient downstream separator, some of this oil will carry over into the pipeline. This can become a significant issue for CO

 geological storage applications since oil contamination in the formation would cause an environmental and safety hazard (and when coke-hardened, may even plug injection lines over time). Alternatively, dry-operating reciprocating compressors could be used, but these are even less mechanically reliable than lubricated compressors.

This discussion is designed to present our perspective on the ongoing debate of reciprocating versus centrifugal compressors within sustainable energy economy gas compression systems. This is an ongoing industry debate that will obviously continue for a long time. We simply gave our opinion based on our engineering experience, and we are sure many will disagree with our assessment, but, regardless of the perspective, it is always important to clearly understand all the features, limits, advantages, and disadvantages of the different types of compressors for any given application when making critically important, long-term equipment and infrastructure decisions.  

Klaus Brun is the Director of R&D at Elliott Group. He is also the past Chair of the Board of Directors of the ASME International Gas Turbine Institute and the IGTI Oil & Gas Applications Committee.

Rainer Kurz is the Manager of Gas Compressor Engineering at Solar Turbines Incorporated in San Diego, CA. He is an ASME Fellow since 2003 and the past chair of the IGTI Oil & Gas Applications Committee.

Articles

Reciprocating compressors present challenges—such as pulsation control, leakage, and mechanical reliability—in CO2 capture and storage applications.

Myth Busters: Part II: Reciprocating vs Centrifugal Compressors for CO2 Capture and Storage: Challenges and Disadvantages

Lube oil selection is extremely important for turbomachines. Mineral oils are frequently used, but the importance of the synthetic oil is increasing. A properly selected synthetic oil can offer superior performance, including resistance to high and low temperatures, a longer service life, and more. 

The fundamentals of a successful lube oil application include:

The lube oil behavior in different operating conditions: 

Specifically, different expected temperatures such as ambient temperature during start-up and operating temperatures. For example, the ambient temperature on a cold winter morning versus a warm summer afternoon. The same lube oil is expected to work properly at high operating temperatures when the turbomachine reaches the peak load. In this case, a synthetic oil with a high viscosity index (VI) and small changes in viscosity with temperature changes is needed. 

Oil additives are added to lube oils for superior characteristics and performance. However, it is extremely important to make sure the intended additives work properly in combination with the base oil. Take into consideration any possible side effects or complications concerning additives, e.g., additive depletion over time, etc. 

ISO viscosity grades (VG) 32-100 are primarily used for turbomachines. Often, ISO VG 150-400 have been used in gear units and high-temperature turbomachinery applications. The oils of interest for turbomachines are typically ISO VG 32, 46, 68, and 100.

Some pumps and compressors are designed to function at high temperatures—temperatures exceeding 150

C. For these high-temp services, lube oil should have oxidative and thermal stability. Most compressors and pumps are best served by oils with ISO VG 32 or 46. Sometimes, ISO VG 68 or 100 is needed for relatively high temperatures. However, given the many different types of compressors and pumps, each manufacturer is likely to recommend only those oils that have been used successfully over long-term operations. This also pertains to other factors, such as service, ambient temperature, climate, etc.

Turbocompressors and centrifugal pumps typically use premium extreme-pressure lube oil—multi-purpose oils for a dependable performance over a wide range of temperatures and operating conditions.

When a compressor is driven by a steam turbine, a single lube oil skid is commonly used and the same lube oil is fed into all the turbomachines. In this case, make sure the lube oil selected is suitable for all the turbomachines it serves. This is a challenge because each piece of machinery has its own set of requirements and considerations, as do different lube oils. 

Often, a gear unit is used with a centrifugal pump, a centrifugal compressor, or other turbomachines in which the gear unit and turbomachine are lubed with the same oil. If this is the case, ensure the selected oil is well-suited for the gear unit, bearings, and other components in a gear-driven turbomachinery train. Synthetic oil formulated from a polyalkylene glycol (PAG) base oil, designed for anti-wear and high temperatures, is usually suitable for this setup. PAG oils are fully synthetic oils used with proper additives for each service. 

Each turbomachine has a specific set of requirements and needs a properly selected lube oil to operate successfully. As a rough guideline, lube oils for turbomachines should have: 

Superb oxidative and thermal stability, especially for medium- and high-temperature turbomachines

High VI means smaller changes in fluid viscosity upon changes in temperature, particularly when a turbomachine is experiencing different temperatures in varying modes of operation, such as start-up, alternative operating, etc.

Relatively low pour points for an easy cold-temperature start-up

Excellent lubricity for enhanced resistance to friction and wear

High resistance to sludge and varnish formation

Compatibility with elastomers and coatings, particularly the sealing components, gear unit internal paint, and other components in contact with the lube oil.

As a rule of thumb, lube oils with ISO VG 32, 46, and 68 are common in turbomachinery applications, such as centrifugal pumps and turbocompressors. The most common is ISO VG 46. 

Amin Almasi is a Chartered Professional Engineer in Australia and the U.K. (M.Sc. and B.Sc. in mechanical engineering). He is a senior consultant specializing in rotating equipment, condition monitoring, and reliability. 

Considerations when selecting a lube oil include oxidative and thermal stability, viscosity, interactions with oil additives, and more.

Turbo Tips: Lube Oil Types & Selection for Turbomachines

Lube oil systems have a significant influence on the efficiency and reliability of mechanical apparatuses such as compressors. Over the years, OEMs have dedicated significant time and resources to improving the understanding of system designs and oil formulations to extend component lifetime and reduce maintenance requirements. The cooling ability of lube oil during compressor operation is key in this regard.

A recent study investigated the potential effect of undissolved air in a two-phase flow on the heat transfer capabilities of compressor lube oil. The study's objective was to observe lube oil re-cooling temperatures that were higher than design calculations on a turbocompressor train in operation.

A comprehensive root cause analysis (RCA) revealed several hypotheses for the higher lube oil temperatures—one of which was undissolved air in lube oil can negatively impact its heat transfer properties. There was limited information on this topic in existing literature; therefore, further investigation was warranted. 

A solid copper cylinder was submerged in a batch of pre-heated and pre-conditioned lube oil containing various amounts of undissolved air. 

 shows that heat flux—the rate of heat transfer over a given unit of surface area—is dependent on the heat transfer coefficient of the oil, the surface area of the cylinder in contact with the oil, and the temperature difference between the oil and the cylinder. The relative heat transfer properties of the oil can be deduced by observing how quickly the copper cylinder's temperature rises once it is submerged. The higher the rate of change, the more effective the oil is at transferring heat.

 shows the experimental setup where the temperature change of the copper cylinder was monitored over time. Several test runs were carried out, taking into consideration different lube oil temperatures, air loadings, and types of lube oil. Three different methods for loading air into the lube oil were also tested.

 Air injection into the lube oil via a nozzle (10 bar compressed air supply delivered through radial boreholes) did not replicate a drained oil condition that would typically be seen during actual compressor operation. Several tests showed that the percentage of air by volume in the lube oil only reached ~1%. At these levels, no material effect on the heat transfer coefficient of the oil was observed.

 The mechanical aeration approach resulted in a lube oil condition similar to that of a typical turbomachinery gearbox. The fraction of air by volume in the oil was approximately 6%. This is comparable to the air content of oil drained from STC-GC internally geared compressors.

 The third test series was performed using oil drained from an STC-GC gear-type compressor.

 shows the heat transfer coefficient over time of 60

C lube oil with and without air bubbles (using the mechanical-aeration approach). The same tests were performed with oil at temperatures of 45

C and with an ISO viscosity class of 46 and 68. All tests showed similar results. As shown in 

, at certain points during the testing, the heat transfer coefficient was reduced by as much as 50% in oil loaded with air.

An approximate 25% reduction in the heat transfer coefficient was observed on the oil drained from the STC compressor on the stand. However, the collection process took roughly three minutes. This likely resulted in some degassing of the oil before testing, which means that the actual reduction in heat transfer may be considerably higher than 25% during operation.

Overall, the study showed that undissolved air can have a significant effect on the heat transfer behavior of lube oil. The content of undissolved air in the lubricant oil strongly depends on the process of air bubble insertion, i.e., injection versus mixing. As a result, the effect of air bubbles on heat transfer may be more pronounced in certain applications where mechanical aeration occurs—for example, in turbosets that utilize gearboxes. 

The results showed that operators are advised to take proactive steps to minimize air-bubble formation in compressor lube oil. An initial recommendation is to perform regular condition monitoring of oil, including measurement of air release time (LAV). Air release time is heavily influenced by deterioration and/or contamination of the oil over its lifetime. Measurements should consider values of air volume fraction found in the real system. A desirable target would be to achieve an air content of less than 1% at the exit of the oil reservoir. 

The experimental approach is not representative of heat transfer at the heat exchanger and/or bearings on a system level. As previously mentioned, the investigations were intended to answer the generic question of whether undissolved air in lubricating oil influences heat transfer, and if so, how significant is the effect. A more accurate determination requires in-situ measurements, which were not part of the investigation.

Bernd Hillemacher is an academic director at RWTH Aachen University and is the managing partner of en2Aix. Manuel Rietz was formerly with en2Aix. Wilko Rohlfs is Professor for Heat Transfer and Thermodynamics, University of Twente, and a freelancer for en2Aix. Marco Simon is the Head of Clarification of Technical Issues at Siemens Energy.

Lube oil's ability to cool affects the efficacy and reliability of turbocompressors, and undissolved air can have a significant effect on the heat transfer behavior of lube oil.

A Case Study: The Effects of Undissolved Air on Heat Transfer Properties of Lube Oil

Integrally geared centrifugal air compressors offer oil-free air by maintaining complete segregation of the air path and the lubrication system. These compressors use air seals to prevent any oil from entering the compressor air path. Because oil is never introduced into the air path, there is no need for additional filtration systems downstream of the compressor to remove oil from the air stream. In contrast to some other technologies, centrifugal compressors also have fewer contacting parts that will wear, resulting in lower maintenance costs and a longer service life. 

To gain more insights into the air compressor industry, 

sat down with Dominic Sarachine, Product Manager at FS-Elliott, during Turbomachinery & Pump Symposia 2023. Sarachine dove into the pros and cons of air compressors, the role they play in power plants, and control systems for compressors' evolution toward smart machine concepts. Additionally, FS-Elliot shared its top takeaways from this year’s show.

Q: What were your top two takeaways from TPS 2023?

I was impressed by how busy and active the exhibitor floor was throughout the entire show. There was a constant stream of suppliers, contractors, operators, students, and many others at our booth this year. This level of participation points toward a continued resurgence in turbomachinery since 2020/2021. There is a renewed focus on diversifying supply chains and reshoring manufacturing to allow for better and more predictable equipment deliveries. 

Additionally, this year's show focused heavily on reliability and efficiency, both in the lectures and by exhibitors. Through advancements in instrumentation and controls, operators can increase the reliability of their machines through more predictive indicators. These indicators allow them to be proactive in performing maintenance on equipment and eliminate unplanned downtime. 

Similarly, efficiency has become even more important as operators look to reduce energy costs and carbon emissions as a result of equipment operation.

Q: What is the role of a centrifugal air compressor versus a lube-oil compressor in a power plant?

Centrifugal air compressors can be used in several applications at a power plant but are most commonly used to provide instrument air. Compressed air is often needed to operate pneumatic instrumentation and control devices, making it critical to plant operation. Compressed air is often referred to as the "fourth utility" after electricity, water, and gas. While many may not think of compressed air when considering the utilities required for plant operation, operators understand that compressor air is just as critical to the continuous operation of the plant as the other three utilities. 

A lube-oil compressor, on the other hand, is designed to lubricate large rotating equipment in a power plant, such as turbines or reciprocating engines. The primary purpose of a lube-oil compressor is to provide pressurized lubricating oil to ensure the proper lubrication and cooling of various components within the machinery it serves.

Q: What advantages and challenges do air compressors present?

There are several types of technologies used to compress air, and each of them comes with different advantages and challenges. Generally speaking, some of the major advantages of air compressors are their versatility, efficiency, environmental impact, and low maintenance requirements. Air compressors also do not produce greenhouse gases or emissions when operated. 

Conversely, air compressors come with a set of common challenges, including initial investment expenses, ongoing energy consumption costs, space requirements, and noise concerns. The upfront costs of air compressors can vary considerably based on the chosen technology and scope of application. However, it's important to note that the most substantial expenditure following the initial capital investment revolves around the energy expenses required to keep the machine running smoothly.

Centrifugal air compressors are specifically designed to have a low cost of ownership as compared to rotary screw compressors or reciprocating compressors. This is due to their overall efficiency and low maintenance requirements; however, the upfront capital costs are typically higher for a centrifugal air compressor. 

Q: What trends or innovations does FS-Elliott see in remote monitoring/control systems for compressors?

Centrifugal compressor control systems continue to evolve toward smart machine concepts that ensure efficient and reliable operation at all times. Key developments that support smart machine operations include the continued development of energy monitoring systems, predictive maintenance systems, and data analytics through remote monitoring. Coupling these systems together not only helps to reduce a user's carbon footprint through CO

emission reductions but can allow for OEM troubleshooting without the lost time and cost of a site visit. 

FS-Elliott's Dominic Sarachine discusses the company's takeaways from TPS 2023 and offers insights into air compressors and centrifugal compressor control systems. 

Q&A: Air Compressors with FS-Elliott

The turbomachinery industry is using augmented, virtual, and mixed realities to create immersive, immediate, and interactive environments that are transforming not only a user’s view of the real world, but the industry’s approach to safety, productivity, design and manufacturing, repairs and maintenance, employee training, customer presentations, and more.

With virtual reality (VR), the user is immersed in a digital environment while augmented reality (AR) overlays virtual objects on top of a real-world environment. Mixed reality (XR) is an extension of AR that blends physical and digital worlds.

Gone are the days when VR and AR were questioned for their functionality and credibility—these are reliable and imaginative tools on the shop floor, in the training room, in the field, and beyond. As Patrick M. Kessler, Global Communications and Digital Marketing Manager at Atlas Copco Gas and Process, pointed out, these immersive technologies are no longer seen as something futuristic or intimidating. “We have found solid business cases for using 3D technologies, where previously it was often seen as pure entertainment,” he said.

Ellie Smith, Product Manager of Augmented Reality at Howden, a Chart Industries Company, echoed Kessler's view: “We are now fully convinced that AR has a place in the way we work and are working hard to embed it as part of our everyday processes. We started our journey with AR five years ago running pilot projects, working on specific standalone challenges to understand how AR tools can work for our business and what problems they can solve for us,” she said. “We’re now at a stage where we’re confident in the technology. We’re beginning to scale up our usage, embed-ding it into our everyday processes for internal use and offering our AR services to more of our customers.”

Remote collaboration is the most popular AR application, according to Inderpreet Shoker, Director of Research at ARC Advisory Group.“ VR is touted as the next-gen solution for taking operator training to the next level. It can create effective training programs with large field of view and complete immersion to help train new workers quickly and efficiently.” She said that research supports the use of AR, indicating that hands-on training programs are more effective compared to presentations and books.

New digital tools and technologies in this space are breaking into the market and further enhancing features, software, graphics, and speed. Meta offers three versions of its VR headset, Meta Quest, with varying forms of graphics, performance, and ergonomics. Microsoft’s XR headset, HoloLens, comes in four offerings, including an industrial edition that is “designed and tested to support regulated environments such as hazardous locations.” According to Microsoft, in manufacturing, HoloLens 2 reduces downtime, increases efficiency by 90%, reduces travel time by 40%, and boosts employee learning of complex tasks.

“The emergence of Meta Quest in VR and Microsoft HoloLens 2 in XR has been historic,” said Kodai Tsushima, xR Application Development Section, Strategic Technologies Research Department at Ebara Corp., parent company of Elliott Group.

“Meta Quest has succeeded in promoting the widespread use of VR with its concept of affordability and PC-free experience. HoloLens 2 projects information into space hands-free and enables scanning of spatial shapes, meeting almost all the requirements of XR in the manufacturing industry. Moreover, with the improvement in PC graphics processing speed, simulations of previously impossible physical phenomena are now possible, and the technology continues to break barriers.”

As Shoker pointed out, AR has opened the door to more dynamic remote collaboration via smart glasses, phones, tablets, etc., “allowing users to connect with remote experts through video calls and receive guidance in real-time using diagrams, markers, instructions, and annotations in the user’s live field of view,” she said. “Many advanced applications also allow users to view critical tasks as well as asset information within their field of view. With digitally created content—including digital twins of assets and equipment—overlaid on a live video stream, AR can provide virtual hands-on assistance.”

Howden uses AR to enhance worker health and safety by helping onsite engineers maintain an awareness of their surroundings. “We can take our AR experiences out of the classroom and into the working environment,” Smith said. “This gives the information we’re showing a contextual grounding—we’re not just looking at data or work instructions in isolation; we’re able to show how that fits into the real working environment.”


The industry is not limiting its use of these technologies, as they are present in the training room, on the shop floor, in the field, and beyond.

For example, Siemens Energy’s collaboration with Microsoft and other partners to create an ecosystem of applications and services that can be integrated into HoloLens 2—”an untethered, self-contained holographic headset that offers the option to include XR applications and information in the physical environment while working heads-up and hands-free,” said Marion Mirold, Head of XR Center of Competence at Siemens Energy. This integration provides XR use cases in-shop and in the field among all project phases.

Another example is the role of AR and VR as a way to enhance employee training and development. “At Atlas Copco Gas and Process, we harness the power of AR/VR, immersing our employees in virtual scenarios that closely resemble real-life situations,” Kessler said. “This hands-on training helps improve employee skills. For example, it is possible to use our virtual models to perform task-site simulations. This allows for potential errors or shortcomings in the field to be identified and rectified immediately.”

The use of virtual and augmented environments also creates another layer of detection in the manufacturing process, as well as increases customer response times, optimizes maintenance and troubleshooting, and guides workers/engineers step-by-step.

Even if the 3D design theory is correct, mistakes can still be overlooked, “during reviews, discovery of problems not seen in the design theory, and difficulties in assembly that can lead to manufacturing problems,” explained Tsushima. “By using VR, it is possible to review designs in life-size (or any desired scale) without the need for prototyping. This enables verification from various angles and helps catch manufacturing problems.”

Shoker said that many OEMs provide AR collaboration tools to end users as a part of their maintenance services. “In many cases, using these tools, remote workers can fix issues themselves with remote guidance from an SME,” she said. These tools can speed up troubleshooting in the field and address issues more efficiently.

The team at Howden uses AR to visualize the next step in an assembly process—”overlaying the locations of piping and instrumentation in a more intuitive way than traditional 2D diagrams,” Smith said. Further, the company’s field service engineers can follow AR work instructions to guide them through each step of a process.

“Our AR-enabled remote support tool, Howden Virtual Expert, supports customers remotely by seeing what they see to help us respond faster to their needs,” Smith said. “AR remote assistance allows us to provide advice to our engineers in the field to achieve a first-time fix and reduce travel costs associated with a site visit by only sending one engineer with the expertise of many provided virtually. AR Work Instructions enables training regardless of location, reduces training time and costs, and enables better reporting and accountability as we capture data about servicing.”

Kessler said that Atlas Copco Gas and Process uses AR/VR similarly, as its service personnel can use these tools to access real-time equipment data and visual instructions during their tasks.

“This instant access to information makes it easier to optimize maintenance and commissioning processes while troubleshooting problems more efficiently,” he explained. “Ultimately, this helps reduce downtime and operating costs.”

AR also benefits customers by allowing companies to present their products and services using 3D models, animations, and more to bring their portfolio to life—and clients don’t even have to leave the office. “Today, we can bring our customers on tours of our different products in remote, inaccessible environments from the comfort of their own offices,” Smith said. “They can engage with the products and get information the way they prefer, by interacting with the content intuitively.”

Further, these technologies offer a perspective to customers that wasn’t easily accessible before. “With large and complex rotating equipment such as ours, it is challenging to look ‘under the hood’ of the actual turbomachinery, especially when it is running,” Kessler pointed out. 

“These 3D technologies enable the customer to take a deep dive into our solutions to understand and experience turbomachinery in a realistic, application-type setting. Our 3D equipment is typically placed inside a photorealistic version of a plant, making the experience even more immersive and relatable for our customer.”

Of course, every technology comes with limitations; however, the confines of these virtual and augmented realities may surprise you. Let’s start with the basics.

Often clients and employees have little to no experience with VR and AR, so it may take an adjustment period. “Generally, there needs to be a certain comfort level and willingness on the user’s end to literally take that leap and immerse themselves in 3D environments,” Kessler said.

In Howden’s case, it mostly uses mobile devices and tablets for its AR because they are familiar technologies, as there is a learning curve with headsets—they require end users to interact with the content in ways that are different from a traditional mouse and keyboard. For example, voice commands—which, even with noise canceling and directional mics, aren’t always practical in noisy environments—and hand gestures.

“Improved hand tracking has helped a lot in the latest HoloLens, but it can still feel quite unnatural,” Smith said. “Personally, I’d like to see a move toward bi-manual gestures, i.e., locking buttons and menus to locations on the hand or arm, and using the other hand to ‘click’—HoloLens does this for its start button, and it feels easier and more intuitive than grappling with virtual buttons floating in space because it gives us that tactile feedback we are used to.”

Plus, headsets are for situational use and cannot be worn all day, but even though they are “more capable compared to smartphones and tablets and can be operated with voice commands or head or hand gestures,” as Shoker pointed out, “most in today’s workforce are not familiar with these newer ways to input data and commands, so it may take more time for the workforce to get used to this technology.”

Beyond the comfort and familiarity with these environments, there are situations in which a physical presence is required when using VR and XR, which can be a barrier in some cases. Additionally, Smith pointed out other basic challenges such as a solid internet connection when working offshore, in a mine, or in very remote areas and a need for more devices that are ruggedized and/or rated for use in hazardous areas.

Further, some limitations depend on the end devices, as Tsushima pointed out, such as head-mounted displays and smart glasses rather than hardware or PCs. “For example, while 3D graphics representation and physics simulation have undergone significant changes in the past five years, HoloLens2 cannot process all of them,” Tsushima said.

In terms of functionality, AR headsets need to pack a lot into one lightweight package: display equipment, high-end graphics processing, batteries, etc. “With current technology, meeting these size and weight constraints means that battery life is limited, and your head warms after wearing a headset for a while, especially loading in large high complexity models,” Smith said. “So, there’s still a need for smaller, lighter-weight components to meet the kind of performance we need.”

At one point, cost was a major barrier, but today it’s not as much of a setback. Over the past several years the cost of hardware, including headsets, has decreased significantly, and, oftentimes, the initial upfront costs are quickly offset by the rate of return.

“The hardware, development, and service costs are very low compared to the savings that can be achieved,” Mirold said. “In many cases, a single successful use of the device can pay off the investment. And little training is required to use the device and the applications.”

Kessler pointed out that the cost of customizing your 3D experience—i.e., the cost of creating and developing a fully immersive digital universe tailored to your specific environment with your tools and products—
is still a sizeable investment. “At the same time, it has provided an even greater return.” He explained that its digital environment was created in a game engine, meaning it can pull multiple outputs ranging from AR to VR, and even singular 3D visualizations.

Beyond hardware, another cost consideration is software. “For us, because of the size of our company, the scale we operate at, and because we want to decentralize the creation of AR experiences to let product and process experts drive content—rather than AR or software experts—it made sense to invest in enterprise-level AR software, mostly SaaS-based and ‘click-and-drag’ style development interfaces,” Smith said. “It comes with some pretty significant costs, but the payoff is it allows us to develop and deploy solutions quickly, and with more input from our business experts because it’s easier for more people to get involved. Software cost doesn’t have to be a barrier to AR, especially for businesses just dipping their toe in the water with a quick proof of concept, but as you scale up, those enterprise features tend to become more important.”

All that said, Kessler doesn’t see any limitations. In fact, a limitless environment is the point of 3D technologies: “removing all limitations in the real world and immersing yourself in another one,” he said.

Mirold agreed: “Every day new use cases are being identified in the different branches of the organization. When the cybersecurity aspects are covered and the data transfer is ensured, even in tough conditions and at very remote locations, the use cases are nearly unlimited.”

As cliché as it may sound, the sky is the limit with these technologies. Currently, the industry continues to invest in AR/VR and look for new ways to integrate it into its economies, and that trend
will continue.

“There will be new processes and applications in plants, and they will require new and, in many cases, more complex equipment technologies,” Kessler said. “Therefore, 3D technologies will not only have significant potential in these fields, but they can also be an essential tool and driver, from internal training to external marketing and other fields.”

Tsushima believes the use of AR and VR will become indispensable. “For example, in design, VR will be used for design reviews, allowing manufacturing to take place without prototyping. In assembly, logistics, and maintenance, AR and XR will be used to support workers. Furthermore, while human judgment is currently relied upon, in the not-so-distant future AI will also be utilized in these areas.”

Again, these tools enable high-quality training with 3D visualizations and interactive training sessions that enhance worker learning in a way that wasn’t possible before. It’s already taken training to the next level, and that can translate into other areas of the workplace. Additionally, AR can support the industry as it struggles to replenish skilled workforces and as folks retire or leave the industry.

“With remote augmented communication and augmented operations, AR can help the industry better address the impending skills gap challenge by capturing and leveraging SMEs using AR technology,” Shoker said. “AR work instructions are a really simple way to capture expert knowledge,” Smith said. “Which may or may not exist in written documentation, and pass it on to our newer, less experienced team members to embed the knowledge in the organization rather than in individuals.” 

The future of VR/AR/XR is vast. “We’re now past the point of AR being some new-fangled gimmick,” Smith said. “We’ve seen the benefits proven over again. The industry is ready, the underlying tech platforms are ready, and I think we’re going to see an acceleration in AR and VR being adopted across the whole supply chain.” 

Augmented and virtual realities increase safety, enable remote support, enhance operator training, and support the design process.

The Immersive Worlds of AR & VR in the Turbomachinery Industry

Camfil: Pulse Filter Technology, TurboPulse

Camfil Power Systems introduced TurboPulse filters, featuring a square inner cage design and aerodynamic TubroVanes that redirect pulse energy and optimize airflow distribution. TurboPulse can fit into filter houses designed for conical cylindrical filters and offers 25% greater dust retention, a 20% lower initial pressure drop, and a 30% pressure drop recovery after each pulse. It is corrosion-proof and 100% incinerable; the inner cage is made of plastic with a high compressive strength. The design has been pulse-endurance tested for over 250,000 pulses. The filters are also designed to save maintenance hours by more than 25% by reducing installation time.

Concepts NREC: Updates Engineering Design System

Concepts NREC updated its Agile Engineering Design System to v2023.2. Engineers can explore cycles for potential carbon emissions reduction in all applications, including the use of hydrogen in combustion and fuel cell applications. The MAX-PAC CAM software works in tandem with its current version of AxCent to optimize moving from design to production. Additionally, MAX-PAC includes new hole-drilling capabilities. 

Riverhawk updated its hydraulic clamp hub to comply with API STD 671, so it is an alternative design to traditional shaft-end connections. The hydraulic clamp hub uses a clamping force on the hub and has been used as a replacement hub on shafts for similar applications, including generators, pumps, and refrigeration systems.

FS-Elliott: P400HPR Centrifugal Air Compressor

FS-Elliott introduced the P400HPR centrifugal air compressor, featuring more aero stages to support higher discharge pressures up to 250 psig. The P400HPR has three stages of compression and is suitable for heat of compression applications. The compressor's aero design reduces the amount of energy used. 

The latest turbomachinery industry innovations.

New Products: Fall 2023

’s November/December 2023 issue features a collection of the latest news and new products from the turbomachinery industry, a how-to guide on selecting lube oil for turbomachines, and a case study on the effects of undissolved air in lube oil. This issue’s cover story is a deep dive into the immersive worlds of augmented (AR) and virtual reality (VR) and how these 3D tools enhance safety, support, training, and much more. In addition to our show report from Turbomachinery & Pump Symposia 2023 (TPS) and an in-tandem Q&A with FS-Elliott—who speaks on its takeaways from the show and offers insights into centrifugal air compressors—the Myth Busters tackle part II of their column on 

Reciprocating vs Centrifugal Compressors for Carbon Capture and Sequestration.

Amin Almasi lays out considerations when selecting a lube oil, such as oxidative and thermal stability, viscosity, interactions with oil additives, etc., in his Turbo Tips column,

 Lube Oil Types & Selections for Turbomachines. 

The Myth Busters Klaus Brun and Rainer Kurz close out their two-part column on reciprocating versus centrifugal compressors in CO

 capture and storage applications. They discuss the challenges reciprocating presents, such as pulsation control, leakage, and mechanical reliability.

, includes reporting on compressing and pumping hydrogen, troubleshooting aero-performance issues, and turbomachinery in LNG production plants, including compressing LNG, cryogenic pumps and expanders, turbine and motor components, and materials. Running in tandem with our show report is a Q&A with FS-Elliott. Dominic Sarachine, Product Manager at FS-Elliott, discusses the company’s takeaways from TPS 2023 and offers insights into air compressors and centrifugal compressor control systems.

Siemens Energy presents a case study on the impact of undissolved air on the heat transfer properties of lube oil: Lube oil’s ability to cool affects the efficacy and reliability of turbocompressors, and undissolved air can have a significant effect on its heat transfer behavior.

The Immersive Worlds of AR & VR in the Turbomachinery Industry, 

shows how the industry is using these 3D technologies in everyday processes and beyond to increase safety, enable remote support, enhance operator training, support the design process, and so much more.

The November/December 2023 issue features augmented and virtual reality coverage, reporting from TPS 2023, a Q&A on air compressors, and more. 