Product Name：SK-1 Sulfided Catalyst for Ultra-deep Hydrodesulfurization of Gas oils
Products：SK-1 Sulfided Catalyst for Ultra-deep Hydrodesulfurization of Gas oils
Clean diesel fuels require low sulfur and aromatics, up to now, most developed countries such as the United States, Europe and Japan request use of diesel fuels meeting European IV specification, i. e., the content of sulfur in diesel less than 50g/g. Hydrotreating process is the most effective technology for desulfurization and dearomatization of diesel fuels, meanwhile, the catalysts with high performance is the key technology for production of clean diesel fuels. Right now, common used commercial catalysts for hydrotreating of diesel fuels are Ni, Co, Mo, W sulfides supported on alumina.
SK-1 is a ultra-deep hydrodesulfurization catalyst for production of clean diesel fuels developed by the Industrial Catalysis Laboratory(ICL) of China University of Petroleum, on the basis of deeply understanding and study on mechanisms of adsorptions and reactions of organic compounds, as well as on catalysis mechanisms of Ni, Co, Mo, W sulfides. Theoretical investigations indicate that the most difficult organic compounds to remove from gas oils are 4 and/or 4,6-alkyl dibenzothiophenes(DBTs). Alkyls in DBTs produce spatial hindrance, embarrassing the approach and adsorption of organic compound molecules on the active site of the catalyst, results low reactivity in hydrotreating of gas oils. Also, it is found from theoretical investigations that the active phases of Ni, Co, Mo, W sulfides for hydrogenation are layered stacks of MoS2 and WS2 nanoparticles, the appropriate stacks of MoS2 and WS2 nanoparticles are favorable to the approach and adsorption of organic compound molecules on the active site, as well as the formation of high active type II active phases.
Besides, up to now, the common commercial catalysts for hydrotreating of diesel fuels are usually saled in Ni, Co, Mo, W oxides supported on alumina. They are sulfurized in the hydroreactor before use into Ni, Co, Mo, W sulfides having hydrogenation activity, this process is so-called “in-situ” sulfurization. The disadvantages of the in-situ sulfurization are as follows. (1) There presents the strong interaction between Ni, Co, Mo, W oxides and the surface of alumina, and forms Mo-O-Al bonds, leading to incomplete sulfurization of metal oxides and formation of low actived “Type I” active phase. This results the low hydrogenation activity of the catalyst. (2) In-situ sulfurization is be time- consuming, generally 3 to 4 days, going to operation time is extended. (3) In-situ sulfurization requires a set of additional specific equipments. These equipments are used only once at the going to operation, and leave unused during operation period of 2 to 3 years, leading to difficulty for maintenance of these equipments. (4) The sulfurazing agents used in the in-situ sulfurization are volatile, toxic and strongly bad smell organic sulfides, results environmental pollution and harms personnel health unavoidably. (5) The H2S and H2O produced during in-situ sulfurization may cause equipment corrosion, leading possibly safety problems. (6) Sulfurization is strongly exothermic reaction, there is overheating risk of hydroreactor during in-situ sulfurization.
Sulfided catalyst, it is called ex-situ sulfided catalyst, is that the catalyst is presulfurized into metal sulfides during manufacture, therefore, the catalyst can be used directly after loading in the reactor, sulfurization in the reactor is not required. Therefore, the disadvantages of the in-situ sulfurization are avoided, moreover, going to operation is simple and operation is convenience. At present, sulfided catalysts become more and more commonly used hydrotreating catalysts in the United States, Japan and Europe. But these catalysts still require accession of protecting agents and oxygen-free loading into reactor. ICL innovates a new technology that the sulfided catalysts are manufactured using soluble metallic salts as precursors. Furthermore, it is found that the metal components sulfurized completely, the strong interaction between Ni, Co, Mo, W oxides and the surface of alumina occurred in the commonly used methods for manufacture of catalysts is avoided completely. No Mo-O-Al bonds are formed, leading to the appropriate stacks of MoS2 and WS2 nanoparticles. Our technology is different completely from ones of other companies in which the supported metal oxides catalysts are manufactured firstly, then presulfurization is carried out at a specific reactor with organic sulfides and sulfur. This novel technology has been patented by the State Intellectural Peoperty Office of P. R. China. ICL developed completely sulfurized NiMoS/Al2O3 catalyst according to this new technology, i. e., SK-1 catalyst, its HDS, HDN and HDAr activities are obviously higher than the similar catalysts of other companies.
SK-1 catalyst was prepared through impregnating sulfide precursor aqueous solution into carrier -Al2O3. As the precursor is sulfide, the strong metal-support interaction could be avoided. Furthermore, the active components are sulfidation state entirely. For hydrotreating application, the presulfidation step that is necessary for oxidation catalysts prior to their utilization is not required in start-up procedure. The catalyst needn’t be presulfurized and the start-up time was shortened remarkably with little pollution, the reactor temperature in start-up process was easily-controlled. Sulfided catalyst SK-1 can be applied to the hydrotreating for inferior quality distillate oils, e.g. straight-run diesel of high sulfur content, FCC diesel, or mixture feed of both, to produce ultra-low sulfur diesel (ULSD). The technology is flexible enough to enable refiners to deal with other clean fuel specifications in addition to sulfur, including density reduction, cetane uplift and aromatics saturation.
■SK-1 catal yst the main physical and chemical
Properties of SK-1 catalyst:
■Excellent performance of SK-1 Catalyst:
SK-1 catalyst shows excellent HDS, HDN and HDAr performance for distillate oils hydrotreating application. Under moderate operation condition with temperature 330～360°C, hydrogen pressure 6～8MPa, LHSV 1～2h-1, H2/Oil(V/V) 400～500 and RFCC diesel as feedstock, the HDS ratio was 99%, HDN ratio was 94%, the cetane number increment was 12-13 units, and the yield of diesel was more than 99%.
■Characteristics of SK-1catalyst：
No the strong interaction between metal oxides and the surface of alumina is present;
Higher density of active sites—higher atomic efficiency;
Higher MoS2 stacks—avoiding steric hindrance;
Higher hydrogenation activity;
Three patents have been authorized to ICL in SK-1 catalyst;
SK-1 catalyst has been manufactured in semi-industrial scale.
■HDS, HDN and HDAr activities of SK-1catalyst for hydrotreating of light cycle oil produced in heavy oil cat-cracker is higher than CK-2 catalyst.
■The comparison CK-2 Catalyst and same kind produt:
Comparison between SK-1 and CK-2 catalysts for hydrotreating of light cycle oil
