Application Of FCC Diesel Hydrofining-dewaxing Composite Technology

Because of the cold winter weather in the northern area, the lowing pour point diesel oil greatly demanded by the motor vehicles. So the hydrofining and hydrodewaxing process which are used in refining the Catalytic diesel and distillate oil(based on wax) to obtain the high-quality diesel with low pour point has a great potential market. The technology has been put into use in the 20×104 t/a hydrofining and hydrodewaxing unit of Qianguo Petrochemical Company to produce -35# and -20# refined diesel oil with low freezing point and meanwhile also produce 0# refined diesel oil usually used in summer .Catalytic cracking unit uses the new technology MIP in company overhaul in 2007.Catalytic diesel oil can obtain the high quality diesel oil through hydrotreating by hydrogenation equipment. catalyst used by the unit is the catalyst hydrodewaxing developed and produced by ChangChun HuigGong company . ZSM一5 molecule sifting catalyst is modified by special treatment process to form HPDW-1 type Hydrodewaxing catalyst, which is with selectivity, anti-ammonia and other characteristics.Inferior diesel oil or distillate oil(based on wax)is firstly put into the Hydrogen refining catalyst beds for hydrofining, then directly to hydrodewaxing catalyst beds for their cracking through shape-selective catalyst, and finally the cracking material will be further refined after hydrogen added.Experiments have proven that hydrofining and hydrodewaxing process at low temperature and pressure condition can down the pour point of diesel oil below -35℃during dealing with Catalytic light diesel oil. The desulfurization and enitrification rate of diesel oil is high, even if refining the poor-quality Catalytic diesel oil, the sulfur content, oxidation stability and other quality of the product also can meet the quality index of light diesel oil. Therefore the process is an effective way to produce the high-quality diesel oil with low freezing point .The result of experiments and industry application shows that the activity of FH-98 and HPDW-1 catalyst is fit for each other and can be arranged in the single stage. The technology is effective both in hydrofining and isodewaxing. It can produce diesel with low pour point, ultra-low sulfur, low density, low T95 and high cetane number. The successful industry application offers a new route to produce clean diesel, and it is suitably for north refinery's demand.