Vol.1 No.3 2009

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Research paper−161 Synthesiology - English edition Vol.1 No.3 (2009) there are high expectations for replacing the conventional hydrodesulfurization catalysts with high-performance and long-life hydrodesulfurization catalysts that minimize feedstock conditioning and process changes leading to feedstock restrictions and decreased throughput, in order to reduce the production cost of sulfur-free diesel.The use of sulfur-free diesel is a global trend (Fig. 1). There is rapidly growing demand from overseas refineries for a high-performance hydrodesulfurization catalyst that makes the production of sulfur-free diesel possible without the need to modify existing refinery equipment or change operating conditions when introducing it. Gas oil used in Japan is heavier than that in Europe and the U.S., and contains large amounts of hard-to-desulfurize sulfur compounds. If a hydrodesulfurization catalyst is developed in Japan, this hydrodesulfurization technology has the potential to be used throughout the world. We have therefore been engaged in research and development to commercialize a hydrodesulfurization catalyst for sulfur-free diesel, to meet the social need for clean transportation fuels.1 Background of ResearchWith enhanced urban air quality control, further reductions are required in tailpipe emissions, particularly nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel vehicles, and various emission reduction efforts are being made involving improvements to engines, exhaust treatment, and fuels. The first two issues are mainly being addressed by the automotive industry, while the third issue is being addressed by the petroleum refining industry. Exhaust-gas treatment devices include diesel oxidation catalysts, nitrogen oxide removal (deNOx) catalysts, and diesel particulate filers (DPFs). However, noble metals and basic oxides used as catalysts are susceptible to sulfur poisoning, which can lead to increased fuel consumption due to increased catalyst combustion regeneration frequency. Because of this, sulfur reduction in diesel fuel has been required in order to accelerate the development of innovative exhaust treatment catalysts.In Japan, the supply of sulfur-free diesel with a sulfur content reduced to below 10 ppm began on a limited scale in 2005 and was subsequently introduced nationwide in 2007. Conventionally, however, the hydrodesulfurization of diesel (sulfur content < 10 ppm) was carried out in an integrated manner through a combination of partial modifications to refinery equipment and the use of a high-performance catalyst, as well as changes in the feedstocks used for hydrotreatment (reduction in hard-to-desulfurize sulfur compounds and nitrogen-rich, high-boiling-point fractions, and reduction in aromatic-compound-rich light-cycle oil (LCO) mixed in), changes in hydrodesulfurization conditions (reduction in oil throughput per unit weight of catalyst), and changes in the hydrodesulfurization process. Consequently, - Full research from in-house laboratory catalyst to commercial catalyst-Yuji Yoshimura*, Makoto TobaResearch Center for New Fuels and Vehicle Technology, AIST Tsukuba Central 5, Higashi 1-1-1, Tsukuba 305-8565, Japan *E-mail : Clean transportation fuels, particularly with significantly reduced sulfur content, are effective in reducing tailpipe emissions and lead to the development of novel high-performance exhaust treatment devices. We have developed a hydrodesulfurization catalyst for sulfur-free diesel with a sulfur content below 10 ppm as well as a catalyst preparation method, and succeeded in commercializing it as a novel desulfurization catalyst through joint research with a catalyst manufacturer.Development of highly-active hydrodesulfurization catalyst for sulfur-free diesel productionKeywords : Sulfur-free diesel, hydrodesulfurization catalyst, catalyst preparation, characterization[Translation from Synthesiology, Vol.1, No.3, p.176-182 (2008)](7)−Fig. 1 Trends in diesel sulfur regulation.

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