Haldia Petrochemical Ltd (HPL) plans to expand capacity in a bid to emphasize on a new product mix that will not increase the consumption of naphtha, but will help improve proceeds of the next petrochemical down-cycle. Extraction of high margin products like Butene-1 from the existing by-products of Naphtha Cracker and associated units, is on the cards. Production is slated to commence in December 2008 and that the new plant will be located in Haldia itself.