Gillian Chew

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

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

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