Gillian Chew

Fluid Catalytic Cracking

Downstream /

Fluid Catalytic Cracking Background At the corporate level, the standard business model for operating a plant focuses on reducing costs and increasing revenue. To achieve these high-level objectives, successful execution at the plant level is essential. Key areas for improvement often include safety, reliability, and environmental impact. In a refinery, optimizing the control of critical control valves is crucial to maximizing production. A well-designed plant modernization package ensuresthat all critical turbomachinery control elements work together seamlessly. This is accomplished through advanced control algorithms, precise measurement, and accurate actuation. Together, these technologies enable operations to effectively advance plant priorities. Maximizing refinery profitability is key. Gasoline and diesel often account for a significant portion of a refinery’s output, so having an efficient Fluid Catalytic Cracking (FCC) unit is essential for producing more of these high demand products. This directly boosts the refinery’s profitability. In summary, the FCC is vital for enhancing the economic value of refinery operations by optimizing the conversion of crude oil into high-demand products, increasing profitability, and providing greater operational flexibility. Fluid Catalytic Cracking Process Fluid Catalytic Cracking (FCC) is a critical conversion process in petroleum refineries, widely used to transform heavy oils into gasoline and lighter products, particularly propylene. The feedstock is injected into a riser, where it is mixed with hot catalyst from the regenerator. In the riser/reactor, large gas oil molecules, facilitated by catalyst, break apart into smaller molecules, which form gasoline and other valuable light products. To ensure efficient chemical reactions, the catalyst bed in the reactor is fluidized for optimal contact. The resulting gas exits the top of the reactor and is further separated in the distillation column. As the process continues, the catalyst particles in the reactor accumulate carbon deposits (coke), which reduce their ability to effectively crack the feedstock. To address this, the spent catalyst is transferred to the regenerator, where it is fluidized with hot air to burn off the coke, restoring the catalyst’s cracking capability. The regenerated catalyst is then returned to the feed riser to repeat the process. Depending on the unit’s capacity and the type of end products being produced, an FCC unit can have up to 250 control valves. The selection of globe or rotary valves often varies due to the erosive nature of the fluids in several applications. REXA has successful installations in many critical FCC applications that require high reliability and precise control.   Featured Fluid Catalytic Cracking Applications Compressor Anti-Surge Learn More Fluid Catalytic Cracking Catalyst Slide Valve Control Learn More Fluid Catalytic Cracking Flue Gas Pressure Control Learn More Steam Turbine Actuator Retrofit Learn More Improved Air Control and Furnace Safety Learn More Turbine Speed Control Hydrogen Recycle Compressor Learn More Literature Download the full Fluid Catalytic Cracking Sub-Industry Brochure here! Download

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Fluid Catalytic Cracking Flue Gas Pressure Control

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Fluid Catalytic Cracking Flue Gas Pressure Control Background Fluid Catalytic Cracking (FCC) is an essential process in refineries used to convert heavy feedstock oil into valuable gasoline, jet fuel, diesel, and other products. During the FCC reaction coke builds up on the catalyst, limiting its ability to carry out the reaction. The spent catalyst is then transferred to the regenerator to burn off the residual coke. As the spent catalyst is regenerated, flue gas (combustion gas) is created by burning off residual coke. The flue gas must then pass through a valve which diverts it to a power recovery train or through a series of separators and electro-static precipitators before being released into the atmosphere. Flue Gas Valve Purpose: Regulate the rate and direction of flue gas exiting the regenerator Helps maintain proper pressure differential between the regenerator and reactor Used for emergency isolation during upset conditions preventing backflow Flue Gas Valve Configuration: Double disc slide valve to provide inherent redundancy Butterfly valve with additional redundancy applied to the actuator system The key to success in this application is in engineering a Flue Gas Valve and actuator assembly that is capable of modulating with position accuracy, while providing fast signal response to control abnormal pressure disturbances. The Flue Gas exiting the regenerator has high pressure, high temperature, high volume, and will contain catalyst particulates. Tight control is critical in maintaining the FCC pressure balance in the cracking process. These conditions can require the Flue Gas Valve to be large in diameter necessitating the use of a hydraulic actuator often controlled by a Hydraulic Power Unit (HPU). Problem Poor Flue Gas Valve performance can create pressure unbalances, which can lead to an inefficient hydrocarbon cracking process. If this condition worsens, it creates potential for unplanned downtime and lost revenue. Common to all HPU systems is their inherent open loop design. Unlike other currently available hydraulic technologies, this design requires an intense maintenance program with frequent intervals. Atmospheric humidity makes contact with the hydraulic oil and creates acid build-up and premature oxidation. Additionally, dirt and particulate from the surrounding air enters the hydraulic system compounding the contamination issue. This is particularly problematic for servo and proportional valve driven hydraulic systems. These servo and proportional valve systems require very specific fluid cleanliness standards. If the fluid cleanliness comes out of spec, the system cannot perform as designed and will result in undesired inconsistent operation and the need to bring the system down for maintenance. The effect of oil degradation requires an HPU to have several filters in the system that must be replaced frequently to effectively clean the oil. There are also dozens of soft goods within these systems that are subjected to high temperatures and need to be replaced periodically before they wear out and become potential leak paths. The pumps within these systems are constantly running to maintain a certain operating pressure for the hydraulic actuator to operate the valve. These continuously running pumps draw a lot of electricity and they must be maintained at a significant cost to ensure the valve and process stay online. Finally, HPU systems often have several hundred feet of hydraulic tubing and hoses which all represent potential leak paths. In order to prevent unscheduled unit downtime, HPU systems are placed on rigorous preventative maintenance programs which are time consuming and expensive. Solution Eliminate the risk of hydraulic oil breakdown, contamination, and maintenance by upgrading to REXA Electraulic™ Actuation. REXA self-contained actuators combine the simplicity of electric operation, the power of hydraulics, maximum reliability, and the flexibility of user-configured control. The principle behind REXA Electraulic™ Actuation is a unique hydraulic circuitry called the Flow Match Valve (FMV) system. The actuator incorporates a bi-directional gear pump coupled to a motor that provides a highly efficient method of pumping hydraulic fluid from one side of the double acting cylinder to the other. The motor and pump only move when a position change is required. Once the target position is reached, the motor and pump shut off and the FMV system hydraulically locks the actuator in place. Motor operation is not required to maintain actuator position; the motor and pump remain idle until a new command signal is received. This maximizes operation efficiency while minimizing wear and tear of the actuator itself. Additionally, the actuator can be configured with full redundancy of full critical components to provide maximum reliability and availability to get you from turnaround to turnaround (TAR). Results With REXA Electraulic™ Actuation the end-user gets all the performance advantages of a hydraulic actuator without the costly maintenance routine. The system provides immediate response to control signal changes and accurately modulates the position of the Flue Gas Valve to ensure efficient and safe process control.  Eliminate the intense preventative maintenance routine of conventional HPU No more routine oil maintenance or fluid conditioning systems No more continuously running pumps wasting energy Achieve accurate Flue Gas Pressure Control with maximum reliability and operational safety Enable stable regenerator pressure with steady differential pressure between the reactor and regenerator Installing a REXA actuator on your Flue Gas Valve allows you to get better control of your FCC process! Literature Download the full Fluid Catalytic Cracking Flue Gas Pressure Control Application Spotlight here! Download

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Fluid Catalytic Cracking Catalyst Slide Valve Control

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Fluid Catalytic Cracking Catalyst Slide Valve Control Background Fluid Catalytic Cracking (FCC) is a refining process used to convert heavier crude oil fractions into usable products such as gasoline, jet fuel, and diesel. In the reactor vessel feed oil is mixed with catalyst particles at high temperatures 900°F (482°C) to 1000°F (538°C), breaking the hydrocarbons into smaller particles. During the FCC reaction coke builds up on the catalyst, limiting its ability to carry out the reaction. The spent catalyst in the reactor chamber is then transferred to the regenerator to burn off the residual coke. Then the regenerated catalyst is transferred back to the base of the reactor riser to be used again. The key to success of this application is Spent and Regenerated Catalyst Slide Valve actuators that provide both reliable positioning accuracy and fast response to the abnormal pressure disturbances that may occur. The valve stroke lengths are typically 8in (20cm) to 24 in (61cm). The Regenerated Catalyst Slide Valve regulates the flow of the regenerated catalyst to the riser, maintaining the pressure head in the standpipe and protecting the reactor from a flow reversal. Maintaining a proper differential pressure is critical for smooth operation. Too high of a pressure difference can lead to excessive catalyst carryover, while too low of a pressure difference can result in poor catalyst circulation. The Spent Catalyst Slide Valve controls the stripper catalyst level, regulates flow of spent catalyst to the regenerator and protects the reactor and main fractionator from a flow reversal. The Spent Catalyst Slide Valve plays a crucial role in maintaining a catalyst barrier, which stops hydrocarbons within the reactor from entering the regenerator. If mixed with oxygen, these hydrocarbons in the regenerator or flue gas train are a safety risk of an explosion. Poor valve performance can create pressure unbalances, which can lead to an inefficient hydrocarbon cracking process. If this condition worsens, it creates potential for unit shutdown and expensive downtime. Problem Traditional Hydraulic Power Units (HPU) are commonly used for positioning in critical FCC applications including the spent and regenerated actuators requiring position accuracy, speed, and response time. However, HPU systems have numerous drawbacks associated with them. Common to all is an “open loop” design. This design characteristic requires an intense and frequent maintenance program. Atmospheric humidity comes in contact with the hydraulic oil and creates acid build-up and premature oxidation. Dirt and particulate from the surrounding air enters the hydraulic system compounding the contamination issue. This is particularly problematic for servo and proportional valve driven hydraulic systems. These servo and proportional valve systems require very specific fluid cleanliness standards. If the fluid cleanliness is not kept within spec, the system cannot perform as designed and will result in undesired inconsistent operation and/or the need to bring the system down for maintenance. These oil cleanliness requirements necessitate the use of filters that must be replaced frequently. There are also dozens of soft goods within these systems that are subjected to high temperatures and need to be replaced periodically before they wear out and become potential leak paths. The pumps within these systems are constantly running to maintain a certain operating pressure for the hydraulic actuator to operate the valve. These continuously running pumps draw a lot of electricity (up to ~$23,000 per year) and they must be maintained at a significant cost to ensure the valve and process stay online. Finally, HPU systems often have several hundred feet of hydraulic tubing and hoses which all represent potential leak paths. In order to prevent unscheduled unit downtime, HPU systems are placed on rigorous preventative maintenance programs which are time consuming and expensive. Solution Eliminate the risk of hydraulic oil breakdown, contamination, and maintenance by upgrading to REXA Electraulic™ Actuation. REXA self-contained actuators combine the simplicity of electric operation, the power of hydraulics, maximum reliability, and the flexibility of user-configured control. The principle behind REXA Electraulic™ Actuation is a unique hydraulic circuitry called the Flow Match Valve (FMV) system. The actuator incorporates a bi-directional gear pump coupled to a motor that provides a highly efficient method of pumping hydraulic fluid from one side of the double acting cylinder to the other. The motor and pump only move when a position change is required. Once the target position is reached, the motor and pump shut off and the FMV system hydraulically locks the actuator in place. Motor operation is not required to maintain actuator position; the motor and pump remain idle until a new command signal is received. This maximizes operation efficiency while minimizing wear and tear of the actuator itself. These slide valve applications can require additional reliability to maximize plant uptime, prevent potential safety issues, and reduce the risk of unplanned shutdown (>$1.7M per day in gasoline production alone). The actuator can be configured with full redundancy of critical components to provide maximum reliability and availability to get you from turnaround to turnaround (TAR). Choosing a redundant REXA system will increase actuator reliability to a value over 99.9%. Results With REXA Electraulic™ Actuation, the end-user gets all the advantages of a hydraulic actuator. The system responds immediately to control signal changes and accurately modulates the position of the Catalyst Slide Valve to ensure efficient and safe process control. Reliability is increased and maintenance requirements are reduced and simplified. Utilizing REXA actuators for Spent and Regenerated Catalyst Slide Valves eliminates the intense preventative maintenance routine of a conventional HPU. This means no more routine oil maintenance, no more fluid conditioning systems with filters, and no more constantly running pumps wasting electricity. Installing REXA Actuators on your Catalyst Slide Valves allows you to reduce and simplify your preventative maintenance list. Catalyst Slide Valves require accurate positioning and immediate response to control signal change. With REXA, end-users gain accurate control with maximum reliability and operational safety enabling stable regenerator pressure and steady differential pressure between the reactor and the regenerator in the FCC. This reassures end-users to have confidence to position their Spent and Regenerated Catalyst Slide Valves and

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Turbine Speed Control Hydrogen Recycle Compressor

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Success Story: Turbine Speed Control Hydrogen Recycle Compressor The turbomachinery operating within a refinery hydroprocessing unit requires some of the most capable actuation in the world. These compressors and pumps must be controlled accurately and reliably for a refinery to meet its operational goals. Typically, this machinery is driven by a steam turbine which converts thermal energy to rotational energy. A poor controlling or unreliable actuator can lead to inefficiency which erodes the bottom line and/or unplanned shutdowns which interrupt throughput. The inlet steam control actuator is arguably one of the most critical and valuable components within hydroprocessing unit. REXA recently upgraded a series of steam turbines driving hydrogen recycle compressors at a refinery in Mississippi. These steam turbines were operated by OEM style hydraulic actuators utilizing pilot valves and power pistons requiring an external oil supply. External oil supply circuits are common in many older OEM actuators systems but come with significant drawbacks. The biggest being oil contamination and a need for frequent and costly maintenance. In addition, the internal varnishing within the system can cause static friction (stiction) resulting in poor control. The original actuator exhibited a position hunting effect which ultimately led to poor control of the steam turbine with large RPM swings – disrupting the downstream process. Refinery personnel consulted REXA’s industrial rotating equipment specialists, who developed a user-specific solution. After reviewing the issues, REXA proposed it’s, “Rotating Equipment Total Integrated Solution.” This specialized package includes an on-site evaluation and training, custom engineered actuator mounting hardware, 3D installation drawings, TAR supervision and support, and actuators/calibration. Literature Read the full Success Story by downloading here!  Download

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Mill Feedwater Pressure Control

Wastewater Treatment, Water and Wastewater, Water Treatment /

Success Story: Mill Feedwater Pressure Control Copper is a valuable metal used in many residential, commercial, and industrial products. From wiring and consumer electronics to HVAC systems to electrical vehicles, copper is an essential element necessary to produce such products. Copper mining is a complex process and water is its’ lifeblood. It allows for the separation and recovery of salable copper. Throughout the milling and flotation cell processed, over double the amount of water is required throughout the crush-grind-flotation-concentrate circuit. Poor control of the mine’s water supply can negatively impact process run-time, leading to constrained production levels and hurting the bottom line. Additionally, as a mine ages, copper ore grade generally decline. To maintain target recovery rates, mines must process more material called ore tons. As time passes this adds to the mine’s overall water consumption.  Around the world mining companies are working to develop a more sustainable production method to address environmental concerns and maintain stable operations. Chile is home to the world’s largest copper mine and it is the country’s largest water consumer. In 2018, the mine underwent an expansion project to implement a desalination plant and added a necessary pipeline to feed the operation. The goal was to operate entirely on desalinated water by the year 2030. In 2020, 10 years ahead of the planned schedule, that goal was achieved. The mine’s water source is pumped over 3,100 meters above sea level to a reservoir near the mine. From there, the water is then delivered through a 36-inch discharge line and is controlled with an 18-inch globe valve. The pond is the sole water supply to the mill andconcentrator.  Greater process control is the hallmark of REXA’s Electraulic™ Actuators. Our actuators are more precise and accurate in performance than pneumatics and more reliable than traditional hydraulic technologies. This mine’s location is remote, arid, and the ambient temperature can drop below 0°C in the winter. For this project, themine had considered pneumatic actuators. The decision was made to not use the pneumatics because of their marginal positioning accuracy and reliability. To keep the concentrator process running, it is crucial that there is water present. Mine operators chose to rely on REXA Electaulic™ Actuators as the final control element to control water flow rate and emergency shutoff. Upon an unexpected loss of power, the linear actuators, equipped with accumulator bottles, produce up to 20,000 lb (89,000 N) of thrust that can safely close the valves using pressurized nitrogen.  In 2021, desalinated water is now used to supply all the copper mine’s water requirements. REXA actuators played a vital role in this successful four-year transition. Our self-contained Electraulic™ system locks the cylinder in place, when no movement is required, minimizing wear and tear on moving components and eliminating unnecessary power consumptions. REXA Electraulic™ Actuators have been engineered for use for constant modulating duty cycle and precise positioning independent of load variation. REXA’s actuation package supports various control system protocols including HART (Highway Addressable Remote Transducer) and Ethernet IP. Pipeline flow control is an excellent example where reliable positioning performance is necessary to prevent and minimize unscheduled downtime! Copper is a valuable metal used in many residential, commercial, and industrial products. From wiring and consumer electronics to HVAC systems to electrical vehicles, copper is an essential element necessary to produce such products. Copper mining is a complex process and water is its’ lifeblood. It allows for the separation and recovery of salable copper. Throughout the milling and flotation cell processed, over double the amount of water is required throughout the crush-grind-flotation-concentrate circuit. Poor control of the mine’s water supply can negatively impact process run-time, leading to constrained production levels and hurting the bottom line. Additionally, as a mine ages, copper ore grade generally decline. To maintain target recovery rates, mines must process more material called ore tons. As time passes this adds to the mine’s overall water consumption.   Around the world mining companies are working to develop a more sustainable production method to address environmental concerns and maintain stable operations. Chile is home to the world’s largest copper mine and it is the country’s largest water consumer. In 2018, the mine underwent an expansion project to implement a desalination plant and added a necessary pipeline to feed the operation. The goal was to operate entirely on desalinated water by the year 2030. In 2020, 10 years ahead of the planned schedule, that goal was achieved. The mine’s water source is pumped over 3,100 meters above sea level to a reservoir near the mine. From there, the water is then delivered through a 36-inch discharge line and is controlled with an 18-inch globe valve. The pond is the sole water supply to the mill and concentrator. Literature Download the entire Success Story here to learn more!  Download

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Process Gas Compressor Flow Control – For Hot Briquetted Iron

Metals Processing, Mining and Metals /

Success Story: Process Gas Compressor Flow Control – For Hot Briquetted Iron In 2020, the largest North American producer of flat-rolled steel completed a new direct reduction plant. The plant produces Hot Briquetted Iron (HBI), a versatile iron source needed to produce steel in electric arc furnaces, basic oxygen furnaces, and blast furnaces. The plant has a closed loop gas circuit that dedusts, compresses, and reheats the gas. Natural gas is also added to the loop. To achieve the highest quality HBI product, optimum process control of product temperature and furnaceatmosphere is required.  In May 2021, the direct reduction plant’s HBI pellets were transferred to their sister company’s blast furnace. In the blast furnace, the HBI blends with coke and iron ore additions. Iron ore is rich in iron oxides, which are reduced by carbon monoxide to form elemental iron and carbon dioxide. Not only are carbon dioxide emissions reduced using HBI on blast furnaces, but also the blast furnaces run more efficiently. Four months into the HBI pellet production, the plant’s operations group had grown increasingly frustrated with their pneumatic actuators. The actuators’ were doing an inadequate job of positioning the compressor Inlet Guide Vanes (IGVs).  Accurate positioning of each compressor on the IGVs is necessary to precisely control the gas throughout, with two compressors in series. Doing this effectively ensures optimal gas flow through the compressor. The compressor IGVs used a pneumatic rotary actuator. During start-up, the pneumatic actuators had one-second delays before moving to position. The slow and inaccurate positioning led to terrible vibration, causing the compressor to shut down. In some cases, up to six manual attempts were tried before the process could restart.  In May 2022, both compressor IGV’s were upgraded with a REXA Electraulic™ Linear Actuator. REXA supported the upgrade by providing a site survey, engineering drawings, and onsite start up commissioning. Plant personnel immediately noticed improved repeatable accuracy to 0.1% of span, regardless of process conditions. The REXA actuators have the capability to open from 0-20%, in under two seconds, without overshoot. For this reason, the plant can now safely start up the compressors without vibration. The process gas stability has also improved, leading to better control of the HBI product chemistry. By utilizing REXA actuators, the steady state process gas flow oscillation was reduced from +/-2,000 m3/hour to +/- 50 m3/hour. Other benefits of improved process control are the reduction in natural gas consumption and less modulating of the 24 downstream control valves. In turn, the control valves’ maintenance intervals were extended. Producing and using HBI contributes to the steel company’s greenhouse gas reduction initiative. REXA actuators contributed to improving the HBI plant operations with improving process gas stability.  Literature Click download to further explore the ROI this plant had in this Success Story!  Download

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Geothermal Power Wellhead Valves

Geothermal, Power /

Success Story: Geothermal Power Wellhead Valves With the demand for renewable energy continuing to increase, geothermal power is quickly becoming a focal point in generation company portfolios. Producing about one-sixth of the carbon dioxide emitted by a clean natural gas fueled plant, geothermal energy production ensures a sharp reduction in greenhouse gas emissions. There are three types of geothermal power designs-dry steam, flash and binary cycles.  Regardless of plant design, everything begins at the wellhead. Often separated from the plant by significant distances, production wells include Emergency Shutoff Valves (ESVs) and flow control valves-both of which play key roles in the process. Therefore, they need to function reliably to ensure no interruption of the flow of steam or brine to the plant.  A geothermal power plant in New Zealand recently experienced unstable control of their production wellhead valves and sought out REXA for a solution. The previously-installed pneumatic actuators were not able to accurately control the valves during both start-up and normal operation. This caused large pressure swings in the process and immense water hammer down the line, which on two separate occasions led to bending pipework and broken pipe brackets.  Leaks within the valve’s stem packing required tightening, making it even more difficult for the pneumatics to overcome the additional packing friction. This negatively affected the pneumatic actuators positioning accuracy resulting in frequent overshoot and correction which lead to water hammer.  This plant needed a solution, and they needed it quickly. Luckily, they already had REXA Rotary Actuators installed on their emergency dump valves! These were used to overcome brine build-up on the disc of the butterfly valves, which helped assure them REXA could overcome any stiction problems on the production wellhead valves. For this reason, as well as the fact that the electro-hydraulic set up of REXA Actuators provide more accurate and reliable control than pneumatics, this plant successfully installed three REXA XPAC Linear Actuators!  Since the initial installation in March 2019, our customer has greatly improved their control of the production wellhead valves with no more large swings in the process. Water hammer down the line is now a thing of the past. Literature Read the full Success Story by downloading here!  Download

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Nickel Mine Oxygen Compressor Inlet Guide Vanes

Metals Processing /

Success Story: Nickel Mine Oxygen Compressor Inlet Guide Vanes A large nickel mine in Ontario, Canada produces nickel metal, which is used in the manufacturing of smartphones and rechargeable batteries that power electric cars. Sulfur dioxide (SO2) is a major air pollutant emitted in the roasting, smelting, and converting of sulfide ores. Fortunately, the SO2 is recovered and utilized to make sulfuric acid (H2SO4), an important coproduct that contributes to the mine’s operational revenue. This high-grade sulfuric acid is used to make recyclable fertilizers and paper products.  Oxygen gas is an important precursor compound required in the expanded process to make sulfuric acid. The gas is generated on site and supplied to the nickel smelter where it is used in flash furnaces that produce iron oxides, sulfur dioxide (SO2), and nickel matte. The sulfur dioxide produced by flash smelting is used to make sulfuric acid,removing the major environmental effect of smelting. Pressurized oxygen must be available to the nickel smelter, or the acid plant will need to halt operations – potentially costing up to $60,000USD per day in revenue. This very scenario worried the nickel mine’s acid plant operations management team since a legacy oxygen plant was beingdecommissioned. This meant there was no longer a backup supply.  The plant has two multistage centrifugal compressors, each powered by a large electric motor. Accurate positioning of the compressor inlet guide vanes (IGVs) is necessary to precisely control the gas throughout the compressor. Doing this effectively ensures the most efficient gas flow through the compressor. The plant operations group grew increasingly frustrated with the pneumatic actuators’ poor performance in positioning the IGVs. The mechanical position switches would drift—requiring recalibration every 6–8 weeks. Due to the compressibility of air, the compressor turndown increased to safely operate without surging, at the cost of compressor efficiency. In 2016, both compressor IGVs were upgraded with six REXA Electraulic™ Linear Actuators. Plant personnel immediately noticed improved accuracy—repeatable to 0.1% of span, regardless of process conditions.  The plant also noticed significant energy savings, since the Electraulic™ Actuators accurately controlled at a higher maximum capacity flow within turndown range. Each compressor had a 0.5 MW power reduction due to the improved air flow and higher compressor efficiency. The annual savings in electricity are calculated to be $1,092,000 USD per year. Literature Read the full Success Story by downloading here!  Download

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Steel Making Reheat Furnace Pressure

Metals Processing /

Success Story: Steel Making Reheat Furnace Pressure Steel companies around the world continuously introduce and enhance processes that emphasize sustainable development. Key sustainable targets include minimizing the environmental footprint and increasing energy efficiency. These companies proactively develop actions to decrease fossil fuel consumption, thus reducinggreenhouse gas emissions. Through all these initiatives, companies proves it is possible to be socially responsible while reducing operational cost to produce quality steel. Modern continuous rolling mills produce large quantities of thin sheet metal but consume significant amounts of energy—particularly with reheat furnaces. These furnaces are gas fuel energy intensive, second only to blast furnaces.  The reheat furnace is located at the hot strip mill and is the process step before hot rolling. In this step, steel billets, plates, or blocks are usually heated from room temperature to ~1,200 C°. At this temperature, the billet can be hot rolled and achieve the desired metallurgical, mechanical and dimensional properties of hot rolled products. Optimal operations require the minimization of fuel consumption, while maintaining a controlled steel billet thermal soak.  From economic, production, and environmental standpoints, the operation of reheating furnaces is of great importance to the steel making process. Economically, the consumption of fuel needed for reheating can represent up to 15% of the operational cost of a rolling process. With respect to productivity, a reheat furnace capacity often dictates the production rate for the rollers, which means that reheating is usually the bottleneck in achieving the maximum production volume. The furnace operation must be reliable, as any downtime will cost the average sized mini mill nearly $45,000 per hour in lost product revenue.  Maintaining a controlled ramp up and holding soak temperature is not a straightforward task. Heat transfer to the steel billets is influenced by internal temperature setpoint of the furnace, flow rate of fuels and flow rate of air. Maintaining furnace pressure is very important. If the furnace pressure is too low, air will ingress in the furnace with oxygen, potentially causing scale formation, impacting quality and productivity. If the furnace operates too high, then the fuel consumption will increase operational cost.  Literature Download the full Success Story here!  Download

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Chemical Processing Turbine Governor

Uncategorized /

Success Story: Chemical Processing Turbine Governor Steam turbines are found in almost any processing plant or power generation facility. Used as the driver for other rotating equipment, steam turbines convert thermal energy to rotational energy — ultimately controlling the input speed or power of a driven device. Any turbine downtime negatively impacts the overall plant process. Therefore,reliable and repeatable control is imperative for efficient plant process and maximum profitability.  A chemical plant in Ohio recently experienced nuisance downtime from process inconsistencies and required improvements to their BDO (butanediol) compressor’s steam turbine governor control valve actuation system. Their system consisted of a simplistic hydraulic power piston actuator, which was challenging to retrofit with LVDT (Linear Variable Differential Transformer) position feedback. Modulating the power piston’s hydraulic relay required its’ driver to make thousands of tiny reversals every hour — adding up to tens of millions of reversals each year.  Thanks to REXA’s Electraulic Actuators, this plant’s concerns are a thing of the past! Our actuators require no oil filters or oil-based maintenance – making them highly reliable. Regular maintenance intervals for our actuators on steam turbine systems are not typically required until after 7-10 years of service, ensuring long-lasting repeatability. High performance allows for control at +/- 1 RPM, allowing fast synchronization and exceptional load control.  Once installed, our customer noticed immediate improvement on the turbine’s speed control and RPM swing. With REXA self-contained actuators, the customer was able to eliminate constant repair and replacement, the need for an external oil supply requiring scheduled maintenance, and many other peripherals within the governor control valve actuator loop such as the LVDT feedback, positioning modules, etc.  Literature Download the full Success Story here to read more!  Download

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