HYDROTREATMENT HDS HDN HDO HDM

REFINING PROCESSING HYDROTREATMENT (HDS, HDN, HDO, HDM) INTRODUCTION – SULFUR PROBLEM INTRODUCTION – SULFUR CONTENT IN FUELS Major Changes in Specification of Diesel and Gasoline INTRODUCTION – SULFUR CONTENT IN FUELS Diesel Fuel Standards Region NA Europe Sweden Previous 500 ppm max 350 ppm 50 ppm (1990) SA China Russia 500 ppm 2000 ppm 2000-5000 ppm Current (2008) 15 ppm (2006) 50 ppm max, 10 ppm (2009) 2-5 ppm (2000) [5% aromatics] ppm [1% aromatics] (2008) 50 ppm 500 ppm (only some areas) 350-500 ppm (only some areas) INTRODUCTION INTRODUCTION Due to depleting supplies of quality petroleum crudes, refineries world-wide are increasingly being forced to use inferior quality heavy oils (HO) for producing clean transportation fuels Unfortunately, the low grades HO are considerably more difficult to process and can significantly reduce the efficiency of clean fuels production From the viewpoint of continual efficient supply of clean fuels, it is therefore critical to improve key HO processes such as sulphur and nitrogen removal HDT REFINING Refining is the process, wherein, one complex mixture of hydrocarbons is classified into a number of other complex mixtures of hydrocarbons or Petroleum refining is an important activity that the product at the end of the process is a source of transportation and involves heating of fuels and petrochemicals Increasing awareness of the impact of environmental pollution by automobiles has shifted the responsibility of pollution control to the refiner’s side PROCESSES IN REFINERIES PROCESS Catalytic cracking Hydrodesulfurisation (HDS) Hydrotreating Hydrodenitrogenation (HDN) Hydrocracking Hydrodeoxygenation (HDO) and (HDM) Catalytic reforming  Hydrotreating: A process used in the oil industry to remove objectionable elements such as nitrogen, sulfur, oxygen and metals from petroleum distillates by reacting them with H2 over a catalyst  Hydrodenitrogenation (HDN): is the removal of nitrogen from nitrogen containing feeds in the form of NH3 The resulting products are hydrogenated  Hydrodesulfurisation (HDS): is the removal of sulfur from sulfur containing feeds in the form of H2S The resulting products are hydrogenated  Hydrodeoxygenation (HDO) and hydrodemetalization (HDM) are the removal of oxygen and metals from the feed  Hydrotreating has been extended in recent years to atmospheric resids to reduce the sulfur and metal content of resids for producing low-sulfur fuel oils The operating conditions of treatment are a function of type of feed and DBT and 4,6-DMDBT conversion for NiMo/P-MCM-41(R) catalysts with NiMo/Al2O3 HDS over sulfided Co-Mo/MCM-41 (50) and Co-Mo/Al2O3 AlSBA-15 SBA-15 possesses abnormal hydrothermal stability The large hexagonal pores (40-100A˚) and bimodal structure consisting of micro and mesopores The high surface area can be exploited for achieving good dispersion of catalytically active transition metal oxides Contd… The large pores of these materials may help larger molecules to have access to the pores thereby enhancing the activity and minimizing the S & N content Diffusion of large molecules like 4,6-DMDBT will be slow in Alumina supported catalyst and the reaction is diffusion controlled With these new and novel supports like nano spherical MCM41 and AlSBA-15 the process are made non diffusional HDS takes place through two routes One by HYDS and the other by DDS Sterically hindered compounds can be desulfurised by hydrogenation using new and novel supported catalysts NiMo/Al-SBA-15 for HDS of 4,6-DMDBT The interaction of Ni and Mo species with the support becomes stronger with Al loading into the SBA-15 Both framework and extraframework Al3+ species participate in the interaction with the deposited Mo species acting as anchoring sites for Mo In line with this, the dispersion of oxidic and sulfided Mo species increases leading to an increase in the catalytic activity of NiMo catalysts NiMo catalysts supported on Al-containing SBA-15 materials with Si/Al molar ratio between 30 and 10 show high activity in HDS of 4,6-dimethyldibenzothiophene This can be attributed to both good dispersion of Ni and Mo active phases and to the bifunctional character of these catalysts, namely, to the participation of Bronsted acid sites of the support in the catalytic transformations of 4,6-DMDBT prior to its desulfurization SBA-15 - MODIFICATIONS BY POST ALUMINATION Chemical grafting of aluminum(III) chloride on the surface of SBA-15 is a suitable synthetic method for the preparation of mesoporous silicoaluminates of SBA-15 type with weak Bro¨nsted acidity This method resulted in the preparation of Al-SBA-15(X) materials without significant changes in the original pore structure and the long-range periodicity order of the parent SBA-15 sample COMPARISION OF DDS OF VARIOUS SUPPORTS FOR MO Mo/MCM-41 Mo/SBA DDS HYD Mo/Al 2O3 Comparison of SBA-15 and Al-SBA-15 supported catalysts with γAl2O3 for HDS of thiophene SBA & Alumina supported Co-Mo Catalysts SBA-15 and Al-SBA-15 supported > γ-Al2O3 supported co-Mo catalysts SBA-15 = Al-SBA-15 supported catalysts for HDS For Hydrogenation reaction Al-SBA-15 is a better support for Mo, CoMo and NiMo than SBA-15 It appears high molybdenum dispersion on isolated Al sites in Al-SBA-15 and consequent increase of anion vacancies at the edge sites of Mo as a function of Si/Al ratio appears to be responsible for the outstanding activities of SBA-15 and Al-SBA-15 supported catalysts Proposed reaction network for the hydrodesulfurization of 4,6-DMDBT over NiMo/Al-SBA-15(X) catalysts Multi-walled carbon nanotubes as efficient support to NiMo hydrotreating catalyst for HDS 3Ni12Mo/MWCNTs Ni12Mo2.5P/MWCNTs 3Ni12Mo/Al2O3 (wb) 3Ni12Mo/Al2O3 (vb); HDS of Thiophene over Pt/AlSBA-15 Schematic representation of tungsten in the surface and wall of WO3-SBA-15: (A) low tungsten content and (B) high tungsten content Impact of high-throughput techniques in the development and launching of a new product CONCLUSION Hydrotreating efficiency can also be increased by employing advanced reactor design such as multiple bed systems within one reactor, new internals in the catalytic reactor or new types of catalysts and catalyst support (e.g structured catalysts) The best results are usually achieved by a combination of the latter two approaches, namely, using an appropriate catalyst with improved activity in a reactor of advanced design [...]...IMPORTANCE  HDS  HDN  Prevention of poisoning of the  Nitrogen containing compounds metal catalysts by sulfur  Control of pollution by SO2 produced in the combustion of fuel  Removal of the unpleasant odour of lube oil caused by the presence of sulfur severely reduce the activity of cracking, hydrogenation, isomerisation, reforming and HDS catalysts  High nitrogen concentrations... desulfurization or hydro-desulfurization (HDS) in which the organic sulfur compounds are converted to hydrogen sulfide Nitrogen removal, also referred to as denitrogenation or hydro-denitrogenation (HDN) in which the organic nitrogen compounds are converted to ammonia Metals (organo-metallic) removal, also referred to as hydro-demetallation or hydrodemetallization (HDM) , in which the organo-metals are converted... and progressively polymerize on the catalyst to form coke The coke deposit is the main cause of catalyst activity reduction KINETICS REACTION RATE INCREASES WITH TEMPERATURE (Arrhenius) Positive for HDS but :  Thermal cracking appears  Thermodynamic limitation for aro saturation  Coke formation on catalyst (deactivation) THE CATALYST Support Normally Normally gamma gamma alumina alumina (γ (γ -Al2O3), ... temperature is a compromise between a long catalyst life, an optimal quantity of catalyst and a hydrotreatment as complete as possible A temperature increase has the following effects, assuming