Chevron Chemical Company
Prior to July of 1994 Chevron disposed of spent xylene by incineration or hazardous waste fuel blending. The facility's alpha olefin production process produces C4 to C30 alpha olefins, the higher molecular weight materials are wax. Periodically the reactors are cleaned with mixed xylene solvent to remove build up of polymer and wax from reactor piping.
It was realized that the spent xylene/polymer mixture could be used as an alternative feedstock to produce pyrolysis gasoline at the on-site ethylene unit. Initially the spent solvent was trucked to the other facility. Direct lines and storage facilities were built to transfer the spent xylene and reduce the potential for spills.
Approximately 500 tons of spent xylene a year no longer has to be shipped off-site for incineration or fuel blending. All the material is being reprocessed into pyrolysis gasoline. Not only is hazardous waste reduced, but the potential for spills and exposure of workers is greatly reduced.
Details of Reductions
Additional Information :
The costs savings resulting from no longer needing to dispose of spent xylene is $68,000 a year. The project will payout in 2.9 years based on waste disposal savings plus increased revenue of $60,000 a year from incremental pyrolysis gasoline production.