to simple media bed changes, predicating development of two hold-down screen solutions within a new StaySafe product platform. While both new patent-pending products are hold-down screens, they facilitate a ‘no-entry’ approach for disassembly and removal from a vessel. Each has a unique and distinctive design based on how the screen is positioned in a vessel. The first new product is a ‘floating’ hold-down screen that rests directly on the top of the media bed. Like all ‘float - ing’ screens, these screens sit on the media bed and must be removed from the vessel before media extraction and replacement can begin. Traditional designs of this type of screen are bolted together and a worker must enter the ves- sel to disassemble the screen and remove it from the vessel. This new design approach incorporates interlocking screen components that are assembled in the vessel with- out tools and secured in place with a central locking hub. This design allows for easy disassembly, capture, and removal of the screen components from outside the ves- sel. It eliminates the need for workers to enter the confined space to remove the screen. Working from outside the ves- sel, simplifies compliance with regulatory safety protocols by eliminating the need for confined space entry permits in the initial stage of media bed replacement. The second new StaySafe product is a ‘supported’ hold- down screen with a manway which rests on support beams within the vessel. Although the main part of the screen fol- lows a standard bolted design, the manway incorporates a unique design so it can be disengaged and removed from the screen from outside the vessel. An integrated man- way screen seal ensures media containment with an easily released panel. This gives the turnaround team the option to remove the manway from the vessel or set it aside in the vessel while the media bed is extracted and replaced. The manway can then be reinstalled and locked back into posi- tion from outside the vessel. Both new StaySafe products have already been installed and are in use today. Each screen has been designed to the high-performance specifications and rigorous standards that Johnsons Screens has been delivering to the gas pro- cessing industry for decades. References 1 API (American Petroleum Institute) Recommended Practice 2217A, 5th Edition, July 2017. 2 OSHA (Occupational Safety and Health Association) Standard 1910.146 Permit-Required Confined Spaces. 3 National Fire Protection Association, NFPA350 – Guide for Safe Confined Space Entry and Work. 4 American Society of Safety Professionals and Approved American National Standard (ASSP/ANSI) Z117.1, 2022, Safety Requirements for Entering Confined Spaces.
Radiometric principles in monitoring refining and petrochemical operations
Accurate measurements, such as monitoring catalyst powder levels in the fourth-stage separator of an FCC, require maximum precision Collaboration with licensor companies and leading EPC companies to upgrade refinery FCC units has led to the introduction of the fourth-stage cyclone in recent years, which is responsible for separating catalyst particles from cracked hydrocarbons after they exit the riser reactor. Efficient separation is crucial for maximising catalyst recov - ery, as any loss of catalyst can impact the economics of the FCC process. The fourth-stage cyclone helps in removing fine cata - lyst particles from the product stream. This is essential for producing high-quality products with the desired speci- fications. Reduced catalyst carryover helps prevent con - tamination of the final products, ensuring they meet the required purity standards. Proper separation in the fourth-stage cyclone ensures that only cracked hydrocarbons are sent to the main frac- tionation unit. At the same time, catalyst particles are circu- lated back to the riser reactor for further catalytic cracking. This promotes the efficient and continuous operation of the FCC unit, contributing to a consistent production rate. The fourth-stage cyclone plays a role in minimising the carry- over of catalyst fines into downstream units, such as the main fractionation column. Minimising catalyst losses is essential for the economic viability of the FCC process, as catalyst make-up and regeneration are significant opera - tional costs. Efficient separation in the fourth-stage cyclone helps prevent the accumulation of coke on the catalyst particles. Coke formation can lead to catalyst deactivation over time, so maintaining catalyst activity is essential for achieving optimal conversion rates and product yields in the FCC process. In summary, the fourth-stage cyclone separator is a critical component in the FCC unit, contributing to catalyst recovery, product quality, temperature control, and overall process efficiency. Its proper functioning ensures the eco - nomic and reliable operation of the fluid catalytic cracking process in petroleum refineries. Powder monitoring Against the backdrop of reliable FCC operations, the lower part of the fourth-stage cyclone, dust level monitoring is of vital importance for correct control of the emitted powder reduction. After exiting the cyclone, the catalyst powders are conveyed to a collection tank and loaded on trucks to landfill sites. Optimising the fourth-stage cyclone yield is essential, where the temperature is lower in the fourth-stage cyclone separator compared to other cyclones due to heat loss from the gas and dust. Regardless, the process temperature is higher than 700°C.
StaySafe is a mark of Johnson Screens.
Johnson Screens Kevin Chase Global Products Manager Contact: Kevin.chase@johnsonscreens.com
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PTQ Q3 2024
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