Plant operators shouldn’t have to continually monitor or adjust their compression system to maintain optimum air mass flowrates. If a plant’s compression and surge control system is antiquated, it can cause delays in operation times, ultimately resulting in potential lost net gains. Both axial and centrifugal compressors are susceptible to surges, which occur when stalls, or small changes to airflow, escalate and cause instability that completely disrupts the airflow in the compressor. These surges can cause stress to compressor parts such as seals, bearings, and drivers, which can lead to extensive damage when unmitigated. This is where compressor controllers come into play. The EM-400 Stand-Alone Compressor Control from Petrotech can replace antiquated control systems with an easy-to-use control system that can be applied across different markets.

What Makes Petrotech’s EM-400 Superior to Other Compressor Controllers?

As one of Petrotech’s premier stand-alone products, the EM-400 Multi-Body Anti-Surge Compressor Controller provides advanced surge protection for up to three compressors using proven algorithms. With multi-compressors, there can be unnecessary recycling that can occur when compressors tend to surge at low rates. The EM-400 eliminates this unnecessary recycling by defining the surge point over a wide range of process gas conditions, resulting in optimum surge protection. Also, with over 45 touch-screen displays, the full-color interface is both user-friendly and password-protected. Specialized features include information on tuning suggestions, alarm statuses, and our exclusive live compressor performance map, allowing operators to closely monitor the compressor controller’s functions and settings. The EM-400 requires no additional hardware for installation, and its slim body makes it perfect for rack mounting.

How Petrotech’s Proven Algorithm Can Benefit Users

Petrotech’s proven surge control algorithm makes the EM-400 stand out among multi-body anti-surge compressor controllers. With over 40 years of experience in providing compressor control systems for thousands of applications, we’ve been able to configure our software to adapt and automatically compensate for changes in molecular weight, temperature, compressibility, pressure, and compressor rotor speed. There are several industries within the energy supply line that use centrifugal and axial compressors for the transportation of pressurized gases and liquids. From electricity production to processing, all can benefit from the accurate monitoring performed by the EM-400. And while the EM-400 provides standard features found in most standalone surge controllers, such as Load Sharing, Pressure Ratio, Fallback Strategies, and Adaptive Gain, it also offers more uniques features, including but not limited to the following:

  • Live Compressor Map
  • Recycle Transfer Control (RTC)
  • Capacity Control
  • Up to Three Recycle Loops in a Single System
  • Secondary Surge Controller
  • Pressure Override Control
  • Backstop Control
  • Built-in Color Touch Screen HMI Display
  • Built-in Sequence of Events Logging/ Display

How Petrotech Helped One Customer With a Compressor and Surge Control Problem

We were able to help one refinery that was operating with antiquated anti-surge and capacity controls. By developing a Triple-Modular Redundant (TMR) control system for this refinery’s multi-compression system, we were able to help the refinery decrease their operating costs and streamline their system. Learn more about this customer success story.

At Petrotech, we’ve been serving the energy supply line with reliable systems for over 40 years. Our goal is to help your production run safer and operate smarter. If you’re in the market for a compressor controller, the EM-400 Multi-Body Anti-Surge Compressor Controller is the complete solution. Contact us online or call us at +1(504) 620-6600 to request a quote.

Powerful, efficient engines of many types supply the energy needed to deliver electricity or drive in the energy supply sector. The oil and gas industry uses combustion engines in three primary markets: power plants, compression, and pumping. In power plants, the engines burn fuel that cannot be used in turbines; in pumping, they provide the mechanical drive; and in compression, they’re used in gas distribution lines. The most popular type of combustion engine in use in these fields today is the reciprocating engine.

What Are Reciprocating Engines?

A reciprocating engine, also known as a piston engine, is one of two types of combustion engines, which work by combusting fuel to create energy. The other type is an earlier form called a rotary engine, and while still in use today, reciprocating engines are more common in many industries. A rotary engine has four separate compartments, and in each one, a specific job is performed: intake, compression, combustion (or ignition), or exhaust. On the other hand, the piston(s) in a reciprocating engine perform each of those four jobs within a single cylinder.

How Do They Work?

The power created by reciprocating engines comes from pressurizing fuel using a piston or pistons to create combustion and, in turn, produce a circular, rotating motion. This process is called the four-stroke cycle as, like a rotary engine, reciprocating engines rely on a repeating pattern of intake, compression, combustion, and exhaust to function. The first step is the intake, in which fuel is injected into the cylinder, pushing the piston to the bottom. Next, during compression, the piston is pushed to the top of the cylinder. This puts pressure on the fuel, and the spark plug ignites it, creating the next step: combustion. This ignition pushes the piston back down, creating energy. Waste is released in the last step, exhaust, and the cycle begins again.

What Are the Advantages of Reciprocating Engines?

Reciprocating engines are the more modern of the two combustion engine types, and in many cases, they have proven to be more efficient. While there is certainly still a place for rotary engines in the market, their uses are much more limited. For example, they’re built into many race cars because they allow for higher torque value, which, in turn, allows for maximum acceleration. However, rotary engines are much more difficult to seal and often have trouble with pressure leakage and lubrication problems. Reciprocating engines come in different configurations to fit specific machines or tasks and are the most common type of engine found in today’s vehicles.

What Sort of Service and Maintenance Do They Require?

Just like the engine in a vehicle, a reciprocating engine in an energy supply facility must be properly maintained and repaired for the highest output and longevity. At Petrotech, we provide solutions for any type of OEM equipment to help our clients monitor, automate, and maintain their reciprocating engines, helping to maximize efficiency and minimize the need for repair. Because we’re able to design and install custom control systems around existing facility equipment, we can help our clients optimize functionality without the extra time or cost of rearranging machinery. Our control systems can include control and monitoring of the following maintenance considerations:

  • Engine Speed
  • Turbocharger Speed
  • Torque
  • Air-to-fuel ratio
  • Exhaust Temperature
  • Air Manifold Pressure
  • Vibration Air Manifold Temperature
  • Ignition timing

Systems are user-friendly and tailored to each client’s requirements.

Petrotech has over 50 years of experience in the energy supply industry and offers turnkey services for single vendor responsibility, including free 24/7 technical support and troubleshooting. Learn more about the custom integrated control systems that we can provide for reciprocating engines.

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In addition to being subject to tough environmental standards, tight budgets, and penalties for supply interruptions, today’s power companies must ensure efficient and reliable operations to keep up with high demand. This means that power-generating turbines often run under more intense conditions than ever, including 24/7 cycles and frequent stopping and starting. Modern steam turbine oils must be able to handle less downtime, higher loads and temperatures, and longer oil drain intervals if they are to be of any effective use. Here’s how steam turbine oils can be selected and used efficiently under demanding operational conditions.

Selecting a Steam Turbine Oil

Maintenance and plant managers can optimize equipment efficiency and cut costs by selecting a steam turbine oil that serves several important functions. First, it must be able to lubricate all bearings, gears, flexible couplings, hydraulic controls, and oil shaft seals. Second, it must be able to resist high temperatures and provide effective cooling. And third, it should prevent corrosion, sludge, and rust while the turbine is spinning. Maintenance professionals can ensure that these performance criteria are met by monitoring several of the oil’s qualities, including its viscosity and viscosity index, demulsibility, rust and corrosion prevention, foam resistance, and oxidation stability.

Viscosity and Viscosity Index

Proper viscosity is what allows oil to efficiently reduce friction between moving parts, making it the most important quality to look for in a steam turbine oil. The size and output of a given piece of equipment will determine its required oil viscosity, with smaller turbines needing lower viscosities and larger turbines needing higher. An oil’s viscosity index, which shows how changes in temperature can affect overall viscosity, is also important. A higher viscosity index indicates that an oil is more likely to maintain its velocity under drastic temperature changes.


Hydro-electric and steam turbines are especially susceptible to water contamination, which can degrade oil and corrode parts. An effective turbine oil will thus have good demulsibility, which is the ability to separate from and resist water. Demulsibility can be measured by mixing 40 milliliters of distilled water with the same amount of turbine oil, stirring for five minutes at 54 degrees Celsius. This emulsion should separate to 3 ml of emulsion remaining within 15 minutes.

Rust and Corrosion Prevention

An effective turbine oil will also need to prevent both rust formation and chemical corrosion. This is achieved through oil additives that attach themselves to metal surfaces and protect them from both metallic oxide formations (rust) and attacks from strong acids and bases (corrosion). It should be noted that excessive amounts of rust and corrosion inhibitors can interfere with other critical oil additives, so it’s important to achieve a balanced formula.

Foam Resistance

A small amount of foam in turbine oil is normal and can generally be permitted. Excessive amounts of foam in oil, however, can overflow and contaminate the whole circulating system, causing damage to pumps, bearings, or other parts and systems. Properly formulated oil will have an adequate amount of anti-foam additives that should help to eliminate excess foam and air.

Oxidation Stability

While it’s stored in the machine’s reservoir, the oil in a steam turbine is exposed to oxygen over long periods of time. This can lead to oxidation, which drastically diminishes the oil’s effectiveness. It’s therefore critical that maintenance and plant managers select a turbine oil with high oxidation resistance, especially in the presence of high temperatures and metallic contaminants, which can speed up the oxidation process.

Since 1978, Petrotech has been providing reliable and innovative control systems to businesses all along the global energy production pipeline. To learn more about our control system solutions for everything from advanced steam turbine controls to single valve fuel gas system retrofits, explore our whitepapers.

In run-of-river hydroelectric plants, it’s essential that the amount of water flowing in the river is properly controlled by a plant control system by varying the hydro turbine generator output and spill gates. Without this control, backups are bound to ensue, leading to costly inefficiencies and environmental impacts.

The Birth of the Hydroelectric Turbine

The need for more efficient, on-demand hydroelectric power was born out of the textile industry in the late 1800s. Before the invention of mechanical turbines for hydroelectricity, textile mills had used water wheels for hundreds of years. But, these wheels were relatively inefficient, mainly due to the backwater that prevented the wheel from turning. Uriah A. Boyden developed the Boyden turbine while working for the Appleton Company in Lowell, Massachusetts. An improvement upon an outward-flow water turbine developed by French engineer Benoît Fourneyron, his turbine added a conical approach passage for incoming water. In 1848, Bowden worked with engineer James B. Francis to further improve the Boyden design and created the Francis turbine, the first mixed-flow turbine. Francis’ high-efficiency turbines were able, for the first time, to precisely match a site’s water flow and pressure.

Run-of-river Control

How is the flow contained and controlled in a run-of-river hydroelectric plant? In run-of-river systems, the generated electricity depends on the amount of water flowing in the river, hence the name. A portion of the water from the river source is diverted to a reservoir. This water is then delivered, through a pipeline, to the power plant. The water then rotates the hydro turbines inside the power plant, which spins a shaft that is connected to a generator, ultimately producing electricity.

These systems minimize the impact of the natural river flow and return water to the river after it is passed through the turbine. The job of hydroelectric control systems for run-of-river plants lies in monitoring river flow, reservoir level, load, and apply a control strategy that optimizes load generation while minimizing environmental impact downstream by smoothly regulating flow back to the river. Control systems offered by Petrotech allow for maximum on-demand flexibility.

The Future of Hydroelectric Power

Currently, the largest hydroelectric power plant is The Three Gorges Dam in China, capturing 84.7 terawatts per hour annually. According to the U.S. Energy Information Administration (EIA), China is actually the largest producer of hydroelectricity in the world. Other countries are utilizing hydro as well—Norway is Western Europe’s largest producer of both oil and natural gas, but it receives 97 percent of its energy needs from hydropower, according to the same report by the EIA. Given that fossil fuels are finite, hydropower presents an efficient, renewable source of energy for locations that have the right set of necessary parameters, e.g., changes in elevation and a naturally flowing water source.

Work With a Control System Provider Devoted to Efficiency

At Petrotech, we seek efficiency in every aspect of our business model. It’s our goal to make sure your business can increase productivity while eliminating operations waste. Our rotating machinery control systems for hydro turbines and generators help hydroelectric companies worldwide do just that. Whether you’re seeking an upgrade or a new install, we can make sure you have the flexible, open, and integrated control system in place that ensures you meet productivity levels. We’ve installed thousands of systems worldwide. To get started on your project, request a quote with us today.