For a refinery, the Fluid Catalytic Cracking Unit (FCCU) is the most important process in the plant. Any restriction in the output can serve as a bottleneck for the entire plant. A crucial part of the FCCU is the Main Air Blower (MAB) and it is responsible for providing oxygen that is used to burn off the coke (also referred to as regenerating) in the catalyst. After the catalyst is used to crack the hydrocarbons into smaller hydrocarbons, it is then cleaned for reuse in the regenerator and fed back into the process once again.
One of the limiting factors in this process is how much oxygen is available for the regeneration process, so if the MAB is not running as designed (loss of motor efficiency or vibration issues), the plant has increased demand, there are seasonal limitations or even worse, the unit fails, the losses could reach in to the millions of dollars per day from lost production.
One of our clients in Louisiana had a 5000HP MAB capable of approximately 28,000 ICFM at 40 PSIG that was experiencing two of the issues mentioned above – loss of motor efficiency (because of age) and high temperatures/humidity (seasonal limitations). Since their MAB was still functional, they needed a smaller option to supplement their process with additional oxygen during periods of high demand or when the summer climate in Louisiana had a negative impact on the efficiency of their blower.
After some discussions to better understand their situation, and factoring in power, space and cooling water availability, Critical Rental Solutions proposed a de-staged 800HP water cooled centrifugal compressor to provide 4000 ICFM at 40 PSIG. The centrifugal would provide them numerous advantages over the typical screw compressor options that they had considered, including minimal footprint, reliability, efficiency and ability to turndown when the full output is not required.
There were other issues left to resolve including the cost and disruption to their process with mobilizing and demobilizing equipment every time the additional CFM would be needed. We helped develop an option to keep the equipment onsite, tied in and ready to go in standby mode at a significantly reduced rate when the unit wasn’t in use. At the end of the day, the solution was cost-effective, reliable and cleared up the bottleneck in their FCCU, ensuring business continuity throughout the plant.