Valero Refining Company has installed a John Zink High Efficiency adsorption/absorption hydrocarbon recovery system to control emissions of all light liquid products loaded onto marine vessels. This process is 98% efficient in capturing and recycling hydrocarbon vapors displaced when loading ships and barges, and returns them back to the refinery for production of gasoline. Vapors displaced from loading are collected and piped onshore were they are adsorbed into a carbon bed and purified air is released to the atmosphere. Two carbon beds are used so that one is on line while they other is regenerated with a vacuum system. Once regeneration is complete, the system automatically switches to allow for continuous recovery of hydrocarbon vapors. Recovered vapor is condensed and absorbed into a circulating gasoline stream and sent back to product storage.
This technology has been used for other petrochemical marine loading operations along the Gulf Coast; however, Valero believes this is the first refinery in Texas to apply the technology to a gasoline marine loading facility.
The source reduction project has reduced VOC emissions by 1,826 tons/year. This equates to an 8% decrease in VOC emissions related to major industrial sources in the Corpus Christi area, an important reduction since this region is a near-nonattainment area. Of the 1,826 tons abated, 63.6 tons of TRI chemicals were prevented from being released.
Details of Reductions
Additional Information :
The process recovers approximately 2 liquid gallons for each 1,000 gallons loaded. Although the project was very expensive and has high operating cost, costs should be recovered in about 12 years.