Offsetting the Cost of Ultra-Low Sulfur Diesel

摘要

Significantly higher hydroprocessing severity will be required to produce the sulfur free (<10 ppm) diesel fuel required in 2006 and beyond. Refiners will accomplish this by one or more of the following approaches:1. Stellar catalyst activity.2. Reduced cycle length.3. Reduced cracked feed content.4. Reduced feedstock endpoint.5. New, higher pressure and/or lower LHSV hydroprocessing units.6. Increased catalyst volume (new reactors in series and or parallel).7. 2~nd stage hydrotreating of the existing 500 ppm product. Unfortunately, there are no magic solutions and all of these approaches increase the cost of producing clean diesel. This paper deals primarily with the last two approaches. A second reactor in a hydrotreater train can produce ULSD but it can also increase the volume and cetane of the product produced. In addition, partial conversion of the product to naphtha is possible further increasing the volume swell and the diesel cetane. All of these features provide additional revenue to offset the cost of a new unit. If some form of investment in new units is required, the best economic solution is usually to simultaneously improve the quality of product and increase yields from that investment. Latest generation base metal catalysts make a two reactor approach even more attractive. Akzo Nobel/Nippon Ketjen’s STARS™ technology and NEBULA™ technology, a joint development of Akzo Nobel Catalysts and ExxonMobil, have the highest activity for this service.