Praxair, Inc. will double the capacity of its Memphis, Tenn., air separation complex to produce oxygen and nitrogen in order to supply Nucor Corp. and Valero Energy Corp. Praxair completed construction of a pipeline capable of serving multiple customers in the Riverport area. A new plant is expected to start up in the third quarter of 2011. As part of the expansion, Praxair will add 400 tons/day of new liquid production to serve growing requirements.