Natural gas processing facilities are turning to new types of technology when choosing rotating equipment for gas compression and process-refrigeration applications. During the past few years, a trend relatively new to midstream has been shaping the future for a smarter, more effective way to design, operate and maintain equipment for modern gas plants.

In particular, compressor automation and equipmenthealth monitoring are becoming favored in the midstream universe as operators look to improve profit margins and operate their facilities more efficiently. The allure of automation lies largely within its ability to monitor machinery health and more tightly integrate rotating machinery into the broader plant operation. It foresees potential mechanical problems, alerts operations personnel to potential developing problems and can be critical to preventing costly unplanned shutdowns.

“Automation is used in a couple of important ways,” Mark McCormick, director of Emerson Climate Technologies’ gas compression and process refrigeration group, tells Midstream Business. “It has become more prevalent because midstream operators are dealing with critical assets such as rotating equipment that may or may not have redundancy.”

Machinery-health monitoring allows plant workers to proactively measure the health of compression-based systems such as gas-gathering compressors, as well as turbo expander and propane-refrigeration systems used to recover natural gas liquids.

For example, automation can monitor the compressor’s main shaft alignment to capture undesirable movement well in advance of equipment failure. Advanced machinerymonitoring systems automatically keep track of equipment vibration and bearing temperatures in order to predict potential failure or maintenance needs. Safety-related automation exists to shut equipment down immediately when they are operating outside of design conditions, often preventing costly, unplanned downtime or failures.

Finally, modern plant-control systems can now include automation considerations for rotating equipment that enable machinery, such as compressors, to operate more efficiently to save energy. Compression is often the largest single energy load in a facility, with excellent potential for optimization with the overall plantcontrol system.

“You can intervene before you start to see major shutdowns,” says McCormick. “Operators want to keep their facilities running. Most plants are continuous operations, and when you have a piece of equipment go down unplanned, it leads to immediate and significant financial losses. With rotating-machinery automation, you can improve visibility to events and conditions and plan proactively for the next shutdown to overhaul it. That ability to plan versus react has enormous benefits to companies.”

Gerald Moodt, area sales manager with Sundyne, has been observing the same automated compressor trends for the same reasons. “It’s helping not only from a potential leak detection standpoint but also to prevent expensive equipment failures and downtime,” he tells Midstream Business.

Detecting problems isn’t the only way automated compressors are cutting spending. Moodt says they’re also helping plants cut back on manpower. He says plants are taking on fewer operators and are instead relying on technology to help operate and control the plants.

Maximizing investments

Traditionally, automation for compression systems has been more widely applied in the oil and gas industry’s downstream sector. In recent years, however, a growing number of midstream operators have begun using automation, too. There is plenty of precedent in the refining and petrochemical world, which has used rotating equipment automation and monitoring as part of broader plant-wide control systems.

The trend began making its entrance among midstream’s biggest players within the past decade. Plantwide automation, including the need for critical rotating machinery such as compressors, is finally taking hold in the design and operation of midstream facilities, says McCormick.

“That integrated degree of thinking about any facility is just starting,” he says. “Most of the major midstream companies have or are considering compression automation as part of the plant-wide control system. The demand for new gas-plant capacity from shale gas production in the past three to four years has led to a dramatic increase in facilities running with modern, distributed-control systems. Even so, many of these plants come online rapidly to be ready to take gas from customers. However, the many plants are not properly operated in a way that maximizes potential for process integration as it relates to machinery-health monitoring and energy savings.”

That’s set to change. Many midstream companies have learned to maximize their automation investment. They are adopting a “downstream facility” mentality by building plants with distributed-control systems that will oversee the entire process, including machinery-health monitoring and energy-use optimization.

Emerson has helped lead some trends in terms of wireless technology, plant-wide distributed-control systems and packaged-refrigeration systems, says Mc- Cormick. “We believe that Emerson is leading the way in building new solutions for modern gas plants. Emerson is uniquely positioned to supply application solutions that integrate plant distributed controls with critical machinery performance—such as Emerson-packaged refrigeration systems.”

Known for its DeltaV distributed-control system, Emerson has not traditionally been involved in supplying rotating equipment. That changed in 2010 when the company bought Vilter Manufacturing. Through this acquisition, Emerson became the only company with single-screw compression technology and the ability to integrate compression- based systems into the plant-wide automation system.

“The midstream is still new at adopting process design aimed at energy and production optimization. As the markets slow and eventually go through economic cycles, the midstream will also slow and follow these cycles. Eventually, midstream capacity growth won’t be based upon continually building more plants; they’ll turn increasingly to adopting new technology and integrated solutions that drive production enhancement and operating efficient gains.”

Smaller sizes

Sundyne, which offers centrifugal gas-compression equipment, has been receiving a growing amount of midstream business in the past three years. Recently, the company began seeing a shift from large to small units. The appeal of smaller units lies within their portability, speed-to-market and less expensive manufacturing costs. They become particularly useful when dealing with stranded gas, which was traditionally flared. Today, smaller units can compress stranded natural gas that isn’t close to a pipeline.

“They’re portable, and you can move a plant into a stranded gas area on a truck,” says Moodt. “When there’s a change in location, you can pick it up and move it to another site.”

In the U.S., there has also been a shift toward smaller sized and geographically distributed gas plants. This has led to smaller new plant-processing capacities designed with more operational flexibility and ability to process richer gas streams. Ultimately this all has led to the use of smaller-compression assets that are often used in multiples for redundancy and plant volume turn-up or turndown capability. Until about 10 years ago, midstream infrastructure was largely based on the Gulf Coast and established fields within the Midcontinent.

McCormick says that changed as the need for regional rich gas processing of shale gas emerged. Views became decentralized and infrastructure build out began much closer to the actual oil and gas fields.

“This meant that new plants have to be smaller, built faster and timed with when gas was coming online from production companies,” says McCormick. “As a result of smaller plants, compressors might now be a fraction of the size of the ones built 15 or 20 years ago in the Gulf. So you have dozens of plants going up in a very short period of time that are smaller, which means the assets inside the plant need more operational flexibility and need to be tightly integrated to overall plant operations planning.”

On the downstream side, FS Elliott makes instrument air compressors that lead liquids through the refining process. The company is finding that more operators are requesting automation within the entire compression system, as opposed to merely the compressor itself, says FS Elliott’s product marketing manager Michael Wik.

“In the past, we were really tasked with supplying the compressor, and maybe if we were supplying another piece of equipment, that would be a stand-alone piece,” he says. “Today, they’re really looking for more engineering support to put the entire package together, and they want us to take more responsibility for the whole system. I think that’s really due to cost issues.”

Higher expectations of vendors are coming as engineering firms take on younger workers who are less knowledgeable than the seasoned engineers of the past. Previously, energy companies took more responsibility in understanding and integrating equipment. Today, they’re turning to companies like FS Elliott for help.

“They’re looking at us and saying: ‘You guys know your compressors, you know your systems. You put it together and do more of the engineering work for us,’ ” says Wik. “In the refining process, tons of instruments and ton of instrument air is needed to complete the refining process. It is a piece that goes into it that gets mixed into the complexity of the rest of the refinery.”