A general view shows the Philadelphia Energy Solutions petroleum refinery in Philadelphia, Pennsylvania December 4, 2014.

He also spoke about his latest venture to build a $9bn petroleum refinery in his native Nigeria - and avoiding corruption in the process.

The chief industries developed here, are petroleum refineries and leather factories.

The company has also developed new ways to use vegetable-based oils in petroleum refineries for the production of diesel.

Those are among 16 petroleum refineries that Valero owns in the United States, Canada, the United Kingdom and Aruba.

Slideshow (5 images) Petrobras has found new ways to refine vegetable-based oils together with diesel in its petroleum refineries.

Petroleum refineries along the U.S. Gulf Coast - more than 40 percent of U.S. capacity - appeared to have survived the storm unscathed.

Petroleum refineries along the U.S. Gulf Coast, which make up more than 40 percent of U.S. capacity, also appeared to be largely undamaged.

There are a dozen petroleum refineries in Canada, and the annual outturn of kerosene is about 200,000 barrels of 45 imperial gallons per annum.