Commonwealth provided engineering, design, procurement and construction assistance for modifications to enable ALON's Big Spring Refinery to comply with the new federally mandated Ultra Low Sulfur Diesel regulations. The revamp of the existing diesel hydrotreater included the addition of a new reactor (shown above) in series with the existing reactor, several new heat exchangers, furnace modifications, charge pump modifications and additional amine filtration equipment. Commonwealth's engineering scope of work included the process design, front end engineering and detailed engineering. Additional process studies investigated relocation of an existing hydrogen plant and pressure swing adsorption system. Commonwealth's mechanical scope of work included specification and fabrication oversight (domestic and European) of the new equipment items through transit to the ALON facility. The engineering phase of the project was completed in the first quarter of 2006. Construction is scheduled for completion during the second quarter of 2006 for a June 1, 2006 unit start-up.