A towering, ongoing reaction
The loop reactor is an easily recognizable application at a polyolefin plant because it towers over everything else. This application looks like a tube or pipe positioned into a tall, skinny loop. The reaction inside is constant because products from the reaction are continuously withdrawn as new reactants are being fed into it.
At petrochemical plants producing polyethylene and polypropylene, the process begins when ethylene or propylene is mixed with a catalyst. The reaction inside the loop reactor turns monomers into polymers, and as the reaction progresses, it transforms from being mostly a liquid to a slurry. During this time, solids are being siphoned away and moving onto the next step in the process while new materials are being introduced.
Operators monitor the density inside the pipe to optimize the reaction and prevent plugging inside the pipe. Maximizing the outcome of the reaction is critical for efficiency, but a plug is an even more costly error. Plugging will initiate a shutdown, resulting in significant downtime and corresponding losses in production. However, getting an accurate density measurement and preventing plugs in this ongoing reaction is easier said than done.