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Catalysis in hydtotreating and hydrocracking
 

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    Catalysis in hydtotreating and hydrocracking Catalysis in hydtotreating and hydrocracking Document Transcript

    • RAJIV GANDHI INSTITUTE OF PETROLEUM TECHNOLOGY By: Kaneti Pramod (e11-0031) Gajendra Ujjenia(e11-0023) Pradeep Naik(e11-0035) Gogineni Sai Srujan(e11-0024)
    • .CATALYSIS OF HYDROTREATING AND HYDROCRACKING Submitted to: DR. Alok Kumar Singh sir DATE OF SUBMISSION : 02-03-2012 By: Kaneti Pramod (e11-0031) Gajendra Ujjenia(e11-0023) Pradeep Naik(e11-0035) Gogineni Sai Srujan(e11-0024 )
    • Abstract:- Hydroprocessing is used in the petroleum refinery to crack larger molecules and/or to remove S, N and metals from petroleum derived feed stocks such as, gas-oil and heavy oil. Hydrocracking is a process in which higher hydro carbons are converted into smaller hydrocarbon .The rate of cracking depends on several factors like temperature ,catalyst. Its main objective is to remove feed contaminants and to convert low value gasoil to valuble products. Purpose of hydrocracking severe form of hydro processing is to break carbon-carbon bonds and drastic reduction of molecular weight. Products more appropriate for diesel than gasoline. Hydrotreating is a process in which nitrogen,sulfar and other hetro atomic compounds. Metals such as nickel and vanadium may be removed from the hydrocarbon stream during hydrotreating. Hydrotreaters may be designated to continuously process one particular hydrocarbon feedstock, or may alternate processing of different feed streams.In other words hydrotreating is a refinery process in which hydrogen gas is mixed withthe hydrocarbon stream and contacted with a fixed-bed of catalyst in a reactorvessel at a sufficiently high enough temperature and pressure to effect the hydro desulfurization (HDS) reactions. In the HDN reaction, the bond between the carbon and nitrogenatoms is broken, and the nitrogen atom is replaced with a hydrogen atom. Hydrotreating process conditions range from the relatively mild reactor conditions of as low as 400 psi and 500°F for naphthas to very severe conditions of up to 2,000 psi and 800°F for heavy gas oils and vacuum residuum. The major catalysts used in the catalysis of hydrotreating and hydrocracking are SENTRY MAX Trap[As], SENTRY MAX Trap[Si], CENTRA DC-2618, CENTRA DC -3630, ASCENT DC- 2513, ASCENT DC- 2532, ASCENT DC-2534, ASCENT DN-3531, CENTINEL GOLD DN-3330
    • Introduction:- A catalyst accelerates a chemical reaction. It does so by forming bonds with the reacting molecules, and by allowing these to react to a product, which detaches from the catalyst, and leaves it unaltered such that it is available for the next reaction. Infact, we can describe the catalytic reaction as a cyclic event in which the catalyst participates and is recovered in its original form at the end of the cycle. A catalyst offers an alternative, energetically favorable mechanism to the non-catalytic reaction, thus enabling processes to be carried out under industrially feasible conditions of pressure and temperature. In petroleum geology and chemistry, Commercial hydrocracking catalysts comprise active metals on solid, highly acidic supports. The active metals are Pd, Ni, Mo or Ni, W, all of which catalyze both hydrogenation and dehydrogenation
    • reactions. The most common supports are synthetic crystalline zeolites and amorphous silica aluminas. Hydrocracking catalyst shapes can be spherical or cylindrical, with gross dimenssions similar to those for hydrotreating catalysts. As already mentioned, in most hydrocrackers, the first few catalyst beds cotain a high-activity HDN catalyst, which also is active for HDS, saturation of olefins, and saturation of aromatics. Other hydrocrackers use a bifunction catalyst – one that is active for both hydrotreating and hydrocracking – in all catalyst beds. Hydrotreating is a refinery process in which hydrogen gas is mixed withthe hydrocarbon stream and contacted with a fixed-bed of catalyst in a reactorvessel at a sufficiently high enough temperature and pressure to effect the hydrosulfurization (HDS) reactions. The catalyst is a solid consisting of a base of alumina impregnated with metal oxides that promote (i.e., catalyze) the desired reactions. For HDS reactions, the most common metal oxides, impregnated in the catalyst are those of nickel and molybdenum. In the HDS reaction, the bond between the carbon and sulphur atoms is broken, and the sulphur atom is replaced with a hydrogen atom. The sulphur atom combines with additional hydrogen to form the toxic gas hydrogen sulphide (H2S). The general chemical formula for the HDS reaction occurring is HDS reaction: 2 (..C-S) + 3 H2 ! 2 (..C-H) + 2 H2S Similarly, in the HDN reaction, the bond between the carbon and nitrogen atoms is broken, and the nitrogen atom is replaced with a hydrogen atom. Hydrotreating catalyst particles are surprisingly small, with diameters of 1.5 to 3.0 mm and length/diameter ratios of 3 to 4. In many units, ceramic balls and successively larger catalyst particles are loaded on top of the first catalyst bed. This “graded bed” protects the bulk of the catalyst by filtering particulate matter out of the feed.
    • Table of Content:- 1. What is catalysis ________________________________________1 2. Catalysis and reaction energetic_____________________________2 3. Types of catalysis ________________________________________3 4. Hydrocracking___________________________________________4 5. Hydro treating __________________________________________6 6. Objective of hydro cracking _________________________________8 7. Objective of hydrotreating__________________________________9 8. Hydro processing Objetive___________________________________12 9. Hydro processing catalysis__________________________________14 10.Types of hydrotreating_____________________________________15 11.Hydro cracking catalysts____________________________________20 12. Hydro treating catalysts_____________________________________22
    • What is catalysis:- Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst unlike other reagent that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations. Catalysts that speed the reaction are called positive catalysts. Substances that slow a catalyst's effect in a chemical reaction are called inhibitors. Substances that increase the activity of catalysts are called promoters, and substances that deactivate catalysts are called catalytic poisons. Catalytic reactions have a lower rate-limiting free energy of activation than the corresponding uncatalyzed reaction, resulting in higher reaction rate at the same temperature. However, the mechanistic explanation of catalysis is complex. Catalysts may affect the reaction environment favorably, or bind to the reagents to polarize bonds, e.g. acid catalysts for reactions of carbonyl compounds, or form specific intermediates that are not produced naturally, such as osmate esters in osmium tetroxide-catalyzed dihydroxylation of alkenes, or cause lysis of reagents to reactive forms, such as atomic hydrogen in catalytic hydrogenation. Kinetically, catalytic reactions are typical chemical reactions; i.e. the reaction rate depends on the frequency of contact of the reactants in the rate-determining step. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst and its "activity". In heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. Analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts. Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, or destroyed by secondary processes. In heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a solid–liquid system or evaporate in a solid–gas system. Catalysis and reaction energetic:- Catalysts work by providing an (alternative) mechanism involving a different transition state and lower activation energy. Consequently, more molecular collisions have the energy needed to reach the transition state. Hence, catalysts can enable reactions that would otherwise be blocked or slowed by a kinetic barrier. The catalyst may increase reaction rate or selectivity, or enable the reaction at lower temperatures. This effect can be illustrated with a Boltzmann distribution and energy profile diagram.
    • In the catalyzed elementary reaction, catalysts do not change the extent of a reaction: they have no effect on the chemical equilibrium of a reaction because the rate of both the forward and the reverse reaction are both affected (see also thermodynamics). The fact that a catalyst does not change the equilibrium is a consequence of the second law of thermodynamics. Suppose there was such a catalyst that shifted an equilibrium. Introducing the catalyst to the system would result in reaction to move to the new equilibrium, producing energy. Production of energy is a necessary result since reactions are spontaneous if and only if Gibbs free energy is produced, and if there is no energy barrier, there is no need for a catalyst. Then, removing the catalyst would also result in reaction, producing energy; i.e. the addition and its reverse process, removal, would both produce energy. Thus, a catalyst that could change the equilibrium would be a perpetual motion machine, a contradiction to the laws of thermodynamics. If a catalyst does change the equilibrium, then it must be consumed as the reaction proceeds, and thus it is also a reactant. Illustrative is the base-catalysed hydrolysis of esters, where the produced carboxylic acid immediately reacts with the base catalyst and thus the reaction equilibrium is shifted towards hydrolysis. The SI derived unit for measuring the catalytic activity of a catalyst is the katal, which is moles per second. The productivity of a catalyst can be described by the turn over number (or TON) and the catalytic activity by the turn over frequency (TOF), which is the TON per time unit. The biochemical equivalent is the enzyme unit. For more information on the efficiency of enzymatic catalysis, see the article on Enzymes. The catalyst stabilizes the transition state more than it stabilizes the starting material. It decreases the kinetic barrier by decreasing the difference in energy between starting material and transition state. It does not change the energy difference between starting materials and products (thermodynamic barrier), or the available energy (this is provided by the environment as heat or light). Heterogeneous catalysts:- In chemistry, heterogeneous catalysis refers to the form of catalysis where the phase of the catalyst differs from that of the reactants. Phase here refers not only to solid, liquid, gas, but also immiscible liquids, e.g. oil and water. The great majority of practical heterogeneous catalysts are solids and the great majority of reactants are gases or liquids. Heterogeneous catalysis is of paramount importance in many areas of the chemical and energy industries. Homogeneous catalysts:- Homogeneous catalysts function in the same phase as the reactants, but the mechanistic principles invoked in heterogeneous catalysis are generally applicable. Typically homogeneous catalysts are dissolved in a solvent with the substrates. One example of homogeneous catalysis involves the influence of H+ on the esterification of esters, e.g. methyl acetate from acetic acid and methanol. For inorganic chemists homogeneous catalysis is often synonymous with organometallic catalysts. Electrocatalysts:- An electrocatalyst is a catalyst that participates in electrochemical reactions. Catalyst materials modify and increase the rate of chemical reactions without being consumed in the process. Electrocatalysts are a specific form of catalysts that function
    • at electrode surfaces or may be the electrode surface itself. An electrocatalyst can be heterogeneous such as a platinum surface or nanoparticles or homogeneous like a coordination complex or enzyme. The electrocatalyst assists in transferring electrons between the electrode and reactants, and/or facilitates an intermediate chemical transformation described by an overall half-reactions. Organocatalysis:- In organic chemistry, the term Organocatalysis (a concatenation of the terms "organic" and "catalyst") refers to a form of catalysis, whereby the rate of a chemical reaction is increased by an organic catalyst referred to as an "organocatalyst" consisting of carbon, hydrogen, sulphur and other nonmetal elements found in organic compounds because of their similarity in composition and description, they are often mistaken as a misnomer for enzymes due to their comparable effects on reaction rates and forms of catalysis involved. Current market:- The global demand on catalysts in 2010 was estimated at approximately 29.5 billions USD. With the rapid recovery in automotive and chemical industry overall, the global catalyst market is expected to experience fast growth in the next years. Industrial Catalysis:- The first time a catalyst was used in the industry was in 1746 by J. Roebuck in the manufacture of lead chamber sulphuric acid. In the start only pure components were used as catalysts, but after the year 1900 multi component catalysts were studied and are now commonly used catalysts in the industry today. In the chemical industry and the industrial research, catalysis play an important role. The different catalysts are in constant development to fulfill economic, political and environmental demands. To achieve the best understanding and development of a catalyst it is important that different special fields work together. These fields can be: organic
    • chemistry, analytic chemistry, inorganic chemistry, chemical engineers and surface chemistry. Some of the large chemical processes that use catalysis today are the production of methanol and ammonia. Both methanol and ammonia synthesis take advantage of the water-gas shift reaction and heterogeneous catalysis, while other chemical industries use homogenous catalysis. HYDROCRACKING:- In petroleumgeology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkanes and alkenes. Simply put, hydrocarbon cracking is the process of breaking long-chain hydrocarbons into short ones. Oil refinery cracking processes allow the production of "light" products such as liquified petroleum gas (LPG) and gasoline from heavier crude oil distillation fractions such as gas oils and residues. Fluid catalytic cracking produces a high yield of gasoline and LPG, while hydrocracking is a major source of jet fuel, diesel, naphtha, and LPG. Thermal cracking is currently used to "upgrade" very heavy fractions ("upgrading", "visbreaking"), or to produce light fractions or distillates, burner fuel and/or petroleum coke. Two extremes of the thermal cracking in terms of product range are represented by the high- temperature process called "steam cracking" or pyrolysis (ca. 750 °C to 900 °C or more) which produces valuable ethylene and other feed stocks for the petrochemical industry, and the milder- temperature delayed coking (ca. 500 °C) which can produce, under the right conditions, valuable needle coke, a highly crystalline petroleum coke used in the production
    • of electrodes for the steel and aluminium industries. Hydro cracking is a catalytic cracking process assisted by the presence of an elevated partial pressure of hydrogen gas. Similar to the hydrotreater the function of hydrogen is the purification of the hydrocarbon stream from sulfur and nitrogen hetero-atoms. The products of this process are saturated hydrocarbons; depending on the reaction conditions (temperature, pressure, catalyst activity) these products range from ethane, LPG to heavier hydrocarbons consisting mostly of isoparaffins. Hydrocracking is normally facilitated by a bifunctional catalyst that is capable of rearranging and breaking hydrocarbon chains as well as adding hydrogen to aromatics and olefins to produce naphthenes and alkanes. Major products from hydro cracking are jet fuel and diesel, while also high octane rating gasoline fractions and LPG are produced. All these products have a very low content of sulfur and other contaminants. Cracking Reactions:-
    • ―Dual‖ means that catalyst has two kinds of active sites – acid-based and metal-based. lists the acids and metals that are used to make these catalysts. Step 1 of the dual mechanism involves adsorption of a paraffin molecule to a metal site, followed by reversible dehydrogenation to form an olefin. In Step 2, the olefin migrates to an acid site, where it reacts with a proton to form a carbenium ion. Step 3, The carbenium ion can rearrange into a more-stable carbenium ion which explains why products from hydrocrackers are relatively rich in iso-paraffins. Step 4, β-scission of the carbenium ionproduces an olefin and a smaller carbenium ion. The olefin can undergofurther cracking on an acid site, or it can react with hydrogen at a metal site. (Step 5) to form a saturated iso-paraffin HYDROTREATING:- With rare exceptions, the intermediate hydrocarbon product streams from the Crude Distillation unit contain levels of sulphur that exceed the specifications for the finished product stream and/or the catalyst specifications for downstream processing units. Hydrotreating is the most common process configuration utilized to remove the sulfur from the intermediate stream. Hydrotreating may also reduce the levels of nitrogen contained in the stream. In addition, some of the metals (such as nickel and vanadium) may be removed from the hydrocarbon stream during hydrotreating. Hydrotreaters may be designated to continuously process one particular hydrocarbon feedstock, or may alternate processing of different feed streams (i.e., a batch-continuous operating mode).
    • Hydrotreating is a refinery process in which hydrogen gas is mixed with the hydrocarbon stream and contacted with a fixed-bed of catalyst in a reactor vessel at a sufficiently high enough temperature and pressure to effect the hydrodesulfurization (HDS) reactions. The catalyst is a solid consisting of a base of alumina impregnated with metal oxides that promote (i.e., catalyze) the desired reactions. These catalysts are usually formed into small pellets(approximately 1/8 inch diameter by less than an inch in length), typically shaped as cylinders or trilobes, to maximize the surface area available for contacting the reactants in the reactors. For HDS reactions, the most common metal oxides,impregnated in the catalyst are those of nickel and molybdenum .
    • In the HDS reaction, the bond between the carbon and sulfur atoms is broken, and the sulfur atom is replaced with a hydrogen atom. The sulfur atom combines with additional hydrogen to form the toxic gas hydrogen sulphide. The general chemical formula for the HDS reaction occurring is HDS reaction: 2 (..C-S) + 3 H2 ! 2 (..C-H) + 2 H2S Similarly, in the HDN reaction, the bond between the carbon and nitrogen atoms is broken, and the nitrogen atom is replaced with a hydrogen atom The nitrogen combines with additional hydrogen to form ammonia (NH3). 1).HDN reaction: ...C-N + 2 H2 ! ..C-H + NH3 The HDS and HDN reactions occur faster (i.e., a higher reactor severity) the higher the reactor temperature, the higher the reactor pressure (which results in an increased partial pressure of hydrogen) and the higher the volume of catalyst in the reactor relative to the volume of oil being processed. For a given crude, when comparing two different boiling point fractions, the fraction with the higher boiling point range generally has the highest concentrations of sulphur and nitrogen in each fraction 2). In addition, the sulphur and nitrogen are more easily removed from boiling compounds. As a result, the reactor severity must be increased, the higher the boiling range of the fraction. HDN reactions generally required a much higher degree of reactor severity than HDS reactions. Hydrotreating process conditions range from the relatively mild reactor conditions of as low as 400 psi and 500°F for naphthas to very severe conditions of up to 2,000 psi and 800°F for heavy gas oils and vacuum residuum. The amount of hydrogen consumed per barrel of feedstock, and correspondingly the amount of hydrogen required in the reactor (called .treat gas.) increases significantly as the feedstocks become heavier. At the higher reactor temperatures and hydrogen partial pressures, in addition to the HDS and HDN reactions, some cracking of heavy molecules into lighter molecules followed by hydrogenation occurs. As a result, very high severity
    • Hydrotreating of heavy gas oils or vacuum residuum is often referred to as Hydrorefining since an appreciable yield of naphtha and distillate hydrocarbons occurs. Generally, the process flow for a Hydrotreater process unit is that the hydrocarbon feedstock and hydrogen streams are both preheated through heat exchange with reactor effluent, then combined either before or after the final heating from a direct-fired furnace and then the mixed hydrocarbon and hydrogen stream is passed through the reactor, flowing from top to bottom. The reactor effluent (hydrogen, light hydrocarbons, H2S and NH3) is cooled through heat exchange with unit feed followed by separation of the vapor and liquid phases. The liquid stream is sent to a stripper tower in which steam (or nitrogen in some cases) is employed to .strip. the hydrogen sulfide and any naphtha and lighter boiling components generated in the reactor from any higher boiling range product streams. Since the resulting naphtha stream contains light ends components, it is referred to as unstabilized naphtha or .wild naphtha.. The stripped liquid product stream is then further cooled prior to disposition to storage tanks for additional refinery processing or finished product blending. The separated reactor effluent vapor stream, which is predominantly hydrogen gas, may be compressed and recycled back to the reactor. A hydrogen.makeup. gas stream (with a hydrogen purity of 75-100% hydrogen, depending on the source of hydrogen) is combined with any recycled hydrogen. OBJECTIVE OF HYDROCRACKING:- • Process Objective: – To remove feed contaminants (nitrogen, sulfur, metals) and to convert low value gas oils to valuable products (naphtha, middle distillates, and ultra-clean lube base stocks). • Primary Process Technique: – Hydrogenation occurs in fixed hydrotreating catalyst beds to improve H/C ratios and to remove sulfur, nitrogen, and metals. This is followed by one or more reactors with fixed hydrocracking catalyst beds to dealkylate aromatic rings, open naphthene rings, and hydrocrack paraffin chains. • Process steps: – Preheated feed is mixed with hot hydrogen and passes through a multi-bed reactor with interstage hydrogen quenches for hydrotreating– Hydrotreated feed is mixed with additional hot hydrogen and passes through a multi-bed reactor with quenches for first pass hydrocracking – Reactor effluents are combined and pass through high and low pressure separators and are fed to the fractionator where valuable products are drawn from the top, sides, and bottom – Fractionator bottoms may be recycled to a second pass hydrocracker for additional conversion all the way up to full conversion
    • OBJECTIVE OF HYDROTREATING:- • Process Objective: – To remove contaminants (sulfur, nitrogen, metals) and saturate olefins and aromatics to produce a clean product for further processing or finished product sales. • Primary Process Technique: – Hydrogenation occurs in a fixed catalyst bed to improve H/C ratios and to remove sulfur, nitrogen, and metals. • Process steps: – Feed is preheated using the reactor effluent – Hydrogen is combined with the feed and heated to the desired hydrotreating temperature using a fired heater – Feed and hydrogen pass downward in a hydrogenation reactor packed with various types of catalyst depending upon reactions desired – Reactor effluent is cooled and enter the high pressure separator which separates the liquid hydrocarbon from the hydrogen/hydrogen sulfide/ammonia gas – Acid gases are absorbed from the hydrogen in the amine absorber – Hydrogen, minus purges, is recycled with make-up hydrogen – Further separation of LPG gases occurs in the low pressure separator prior to sending the hydrocarbon liquids to fractionation. SINGLE STAGE HYDROCRACKING:- TWO STAGE HYDROCRACKING:-
    •  May use separate reactors with desulfurization & olefin saturation in 1st reactor & hydrocracking in 2nd reactor » 1st reactor removes contaminants & saturates aromatics » Can also do part of the hydrogenation conversion Effluent from 1st reactor sent to fractionator — hydrocracking reactor fractionator bottoms sent to the 2nd stage.
    • • Naphtha Hydrotreating– Primary objective is to remove sulphur contaminant for downstreamprocesses; typically < 1wppm • Gasoline Hydrotreating– Sulfur removal from gasoline blending components to meet recent cleanfuels specifications • Mid-Distillate Hydrotreating – Sulfur removal from kerosene for home heating – Convert kerosene to jet via mild aromatic saturation – Remove sulfur from diesel for clean fuels • Ultra-low sulfur diesel requirements are leading to major unit revamps • FCC Feed Pretreating– Nitrogen removal for better FCC catalyst activity Sulfur removal for SOx reduction in the flue gas and easier post-FCC treatment – Aromatic saturation improves FCC feed ―crackability‖ – Improved H/C ratios increase FCC capacity and conversion.
    • Purpose of hydrotreating 1. Remove heteroatoms and saturated carbon- carbon bonds. a) Sulphur, nitrogen ,oxygen and metals removed. b) Olefinic and aromatic bonds saturated. 2. Minimal cracking 3. Minimal conversation-10% to 20% typical. 4. Products suitable for further processing or final blending. a) Reforming, catalytic cracking, hydrocracking. Purpose of hydrocracking:- 1. Severe form of hydroprocessing. a) Break carbon carbon bonds. b) Drastic reduction of molecular weight. 2. Reduce average molecular weight and produce higher yields of fuel products. 3. 50% + conversion 4. Products more appropriate for diesel than gasoline. Hydroprocessing objectives:- Feedstocks desired products process objectives. Napthas Catalytic reformer feed. Removal of S,N,Olefins. LPG Hydrocracking Atmospheric gas oils Diesel Removal of S,aromatics and n-paraffins. Jet Removal of S and aromatics. Ethylene feedstock Removal of aromatics. Naptha Hydrocracking Vaccum gas oils. LSFO Removal of S FCC feed Removal of S,N and metals. Diesel Removal of S and aromatics hydrocracking Kerosene/jet Removal of S and aromatics. Naptha Hydrocracking
    • LPG Hydrocracking Ethylene feedstock Removal of aromatics hydrocracking Lube oil base stock Removal of S,N and aromatics hydrocracking. Residuum LSFO Removal of S FCC feedstock Removal of S,N CCR and metals. Coker feedstock Removal of S,CCR and metals. Diesel Hydrocracking Characteristics of petroleum products. Characeristics of petroleum processing LPG Crude oil Hydrogenation Coke Cracking Average carbon no. (atoms per molecule) Hydroprocessing trends. 1. Hydrogen is ubiquitous in refinery and expected to increase a) Produces higher yields and upgrade the quality of fuels. 2. The typical refinery runs at a hydrogen deficit. a) As hydroprocessing become more prevalent , this deficit will increase. b) As hydroprocessing progresses in severity, the hydrogen demands increase dramatically. 3. Driven by several factors. a) Heavier and higher sulphur crudes. b) Reduction in demand for heavy crude oil. c) Increased use of hydrodesulfurization for low sulpur fuels. d) More complete production of FCCU catalysts. e) Demand for high quality coke. f) Increased production of diesel
    • Sources of hydrogen:- 1.catalytic reformer. a)The most important source of further refiner. b)Continuously regenerated reformer: 90 vol% c)Semi- continuously regenerated reformer: 80 vol% 2. FCCU of gas. a) 5vol% hydrogen with methane,ethane and propane. b) several recovery methods (can be combined). -cryogenic -pressure swing adsorption -membrane separation. 3. steam methane reforming. a) most common method of manufacturing hydrogen. b) 90 to 95 vol% typical purity. 4. Synthesis gas a) Gasification of heavy feed b) Hydrogen recovery- pressure swing adsorption or membrane separation. c) More expensive than steam reforming but can use low quality by product streams. Hydroprocessing catalysis:- (a)Hydrotreating 1. Desired function a) Cobalt molybdenum-sulfur removal and olefin saturation. b) Nickel molybdenum- nitrogen removal and aromatic saturation. 2. Reactor configuration. a) Downflow fixed bed-temperature to control final sulphur content. b) First bed may guard bed for nickely and vanadium. -cheaper catalysts -more removal of heteroatoms in subsequents Beds 3. Selective catalysts for sulphur removal without olefin saturation a) Maintaining high octane rating
    • (b)Hydrocracking 1. Crystalline silica alumina base with a rare earth metal deposited in the lattice. a) Platinum ,palladium, tungsten and nickel. 2. Feed stock must first be hydrotreated. 3. Catalysis deactivate and coke does form even with hydrogen present. a) Hydrocracker require periodic regeneration of the fixed bed catalysis system. b) Channeling caused by coke accumulation a major concern. c) Can create hot sports that can lead to temperature runaways. 4. Reactor configuration a) Ebullient beds-pelletized catalyst bed expanded by upflow of fluids. b) Expanded circulating bed- allows continuous withdrawal of catalyst for regeneration Types of hydrotreating. Natptha hydrotreating 1. Naptha hydrotreated primarily for sulpur removal. a) Mostly mercaptans (R-SH) and sulphides (R-S-R’) b) Some disulphides (R-S-S-R’), and thiophenes (ring structures). 2. Cobalt molybdenum on alumina most common catalyst. 3. Chemical hydrogen consumption typically 50 to 250 scf/bbl a) For desulphurisation containing up to 1 wt% sulphur- 70 to 100 scf/bbl b) Significant nitrogen and sulphur removal- 250 scf/bbl Naptha hydrotreating process. 1. Reactor typically at 200 psig and 700 degree farenheit. a) Temperature increases to compensate for decrease in catalyst activity. 2. Liquid space velocity = 2 per hour. 3. Hydrogen recycle = 2,000 scf/bbl. 4. Acid gas removal may not be directly incorporated into recycle gas loop. a) Overhead vapour from fractionator to saturates gas plant to recover light hydrocarbons and remove H2S 5. Product fractionation. a) Pentane/ hexane overhead either to blending or isomerisation b) Bottoms to reformer.
    • Distillate Hydrotreating:- Product Information - Distillate Hydrotreating Catalyst Type/Applications Description SENTRY MaxTrap[As] NiMo - Distillate Hydrotreating - Arsenic trap A trilobe catalyst on a high surface area alumina extrudate specially formulated to trap Arsenic (As) present in a wide range of petroleum feedstocks. Protects high activity catalysts for significantly longer periods from arsenic poisoning. Demonstrates exceptional stability in this severe environment. SENTRY MaxTrap[As] NiMo - Distillate Hydrotreating - Arsenic trap A trilobe catalyst on a high surface area alumina extrudate specially formulated to trap Arsenic (As) present in a wide range of petroleum feedstocks. Protects high activity catalysts for significantly longer periods from arsenic poisoning.
    • Demonstrates exceptional stability in this severe environment. SENTRY MaxTrap [Si] CoMo - Distillate Hydrotreating CRITERION DC-200 is a high activity, high stability Cobalt Molybdenum/Alumina catalyst. CoMo - ULSD production Centinnel DC-2110 is a high activity catalyst for the production of ULSD. Features enhanced aromatic saturation and nitrogen removal activities compared to conventional catalysts, contributing to improved stability. CoMo - Distillate Hydrotreating High activity, low density catalyst for production of Low Sulfur Diesel (<50- 500+ppm) CoMo - ULSD production Highest activity catalyst ideal for producing ULSD at moderate-to-high operating pressures, especially when it is critical to limit hydrogen addition to the feed. CENTERA DC- 2618 CENTERA DN- 3630 CoMo - ULSD Ideal catalyst for producing
    • ASCENT DC- 2531 production ULSD at low-to-moderate operating pressures, especially when it is critical to limit hydrogen addition to the feed. ASCENT Catalyst Technology, Criterion’s latest innovation, increases catalyst performance by expanding promoter metal utilisation through an enhanced catalyst physical structure. ASCENT DC- 2532 ASCENT DC- 2534 ASCENT DN- 3531 NiMo - Distillate Hydrotreating High activity, low density catalyst for improved HDS and HDN at higher hydrogen partial pressure or used in stacked bed combination with cobalt molybdenum to improve overall system stability. NiMo-ULSD production CENTINEL™Technology, high activity catalyst for production of Ultra Low Sulfur Diesel (<10ppm) at moderate-high hydrogen partial pressure.
    • GAS OIL HYDROTREATING:- Normally two reactor beds-temperature rise Amount of hydrocarbon related to ring saturation and sulphur. For long ring 300 psig may be sufficient. 1200 psig will be converted
    • HYDROCRACKING CATALYSTS:- A hydrocracker is one of the most profitable units in a refinery, partly due to the volume swell, and partly because it converts heavy feedstocks to lighter and more valuable products such as naphtha, jet-fuel, kerosene and diesel. The unconverted oil may be used as feedstock for FCC units, lube oil plants and ethylene plants. Any improvement in the hydrocracking unit operation significantly improves overall refinery economics. The proper selection of hydrocracking catalysts offers a great potential for enhancing the performance of the hydrocracking unit with respect to yield structure, product properties, throughput and cycle length. For optimum performance of a hydrocracking catalyst, it is important to have a highactivity hydrotreating catalyst in front of it to convert organic nitrogen and heavy aromatic compounds to low levels. Topsøe offers a complete catalyst solution ,
    • comprising hydrotreating and hydrocracking catalysts as well as grading and guard catalysts. -Maximum middle distillate hydrocracking catalysts:- For hydrocracking catalysts, there is often a trade-off between catalyst activity and product selectivity. There can furthermore be a trade-off between the various product properties such as the smoke point of the jet fraction, the cetane number and cold flow properties of the diesel fraction and the viscosity index of the unconverted oil. At the same time, the refiner is often interested in limiting hydrogen consumption . The tools that catalyst developers have at hand to address these various requirements are balancing the hydrogenation function with the acidic function and modifying the two functions. As a result of extensive R&D efforts, Topsøe has developed and commercialised two series of hydrocracking catalysts which in combination with the appropriate Topsøe pretreater catalysts from the BRIM™ series have shown to provide a step-out performance compared to existing hydrocracking catalysts in the industry. The red hydrocracking catalyst series provides exceptional middle distillate yields combined with excellent product properties including high cetane number for diesel, high smoke point for kerosene and high viscosity index for unconverted oil: The blue hydrocracking catalyst series provides an even better middle distillate yield with superior cold flow product properties compared to the red series The red series:- TK-925 is a maximum distillate catalyst. Its main objective is to maximise high-quality diesel yield while producing unconverted oil with excellent qualities for lube oil plants or for FCC units. TK-931 is a middle distillate catalyst designed to produce very high yields of premiumquality diesel, jet-fuel and lube oil base stocks. Specifically, this catalyst gives a high smoke point for jet, an excellent cetane number for diesel fraction and a high viscosity index (VI) for lube base oils. TK-941 and TK-951 are the recommended catalysts when both high activity and high yield are important. TK-951 is more active than TK-941, and both provide excellent middle distillate yields with efficient hydrogen utilisation. TK-947 is optimised for units at high space velocity and/or low unit pressure. TK-947 has shown excellent performance in both catalyst activity and stability and in product yields and properties. The blue series TK-926 has a high selectivity for diesel production. The acid function of TK-926 has been modified to enhance the isomerisation reactions and improve the cold flow properties of the products. TK-933 and TK-943 are medium-activity catalysts to be used in services, where very high middle distillate yields, very good cold flow properties and optimised hydrogen consumption are a must. The diesel cloud point is typically 10-20°C (18-36°F) lower than that obtained with other catalysts A special acid function modification is used to improve the isomerisation activity and the middle distillate selectivity. TK-943 is more active than TK-933.
    • CATALYSIS OF HYDROTREATING: Hydrotreating catalysts are primarily used to remove sulfur, nitrogen and other contaminants from refinery feedstocks. In addition, they improve product properties by adding hydrogen and in some cases improve the performance of downstream catalysts and processes. Albemarle offers a wide range of hydrotreating catalysts to treat the lightest to the heaviest feedstocks while meeting cycle length and product property objectives KF 757KF 757 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst family. It has close to 100% Type II active sites which gives it exceptional activity in high severity applications such as ultra low sulfur diesel. It also has a very open pore structure for application in heavier feed applications such as FCC-PT. KF 767KF 767 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst family and having nearly 100% Type II active sites. KF 767 has been specifically designed for producing ultra low sulfur at moderate pressure and without excessive hydrogen consumption. It achieves significantly higher activity than previous catalyst generations when HDS activity is controlled by nitrogen inhibition. KF 770KF 770 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst family. It has close to 100% Type II active sites which gives it exceptional activity in high severity applications such as ultra low sulfur diesel. KF 770 has been optimized to balance hydrogenolysis and hydrogenation based desulfurization in low to medium pressure ULSD units. KF 771KF 771 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst family. It has 100% Type II active sites which provide exceptional activity in ultra low sulfur diesel (ULSD) applications. KF 771 has been optimized to provide very high HDS activity and excellent stability in ULSD units operating at moderate pressure and processing some cracked feedstocks. KF 772KF 772 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst
    • family. It has 100% Type II active sites which provide exceptional activity in ultra low sulfur diesel (ULSD) applications. KF 772 has been optimized to provide very high HDS activity and excellent stability in ULSD units operating at moderate to high pressure and processing some cracked feedstocks. KF 848KF 848 STARS™ is a super-high activity NiMo catalyst utilizing STARS™ technology to ensure near 100% Type II active sites.It is recommended for denitrogenation and dearomatization in high severity service, such as hydrocracker pretreatment. It is also ideal for higher pressure diesel HDS units for the ultra-deep desulfurization of distillates to 50 ppm or lower, achieving extra density reduction and dearomatization. hydrocracking applications Many hydrocrackers in the refineries operate in mild hydrocracking mode. For these units, the main objectives are to obtain a certain minimum conversion as well as to meet specific product properties such as sulphur content, density and cetane number. Typical pressures are in the 60-110 bar (850-1560 psig) range. Typical conversion is 10-20% for lower pressure units and 30-50% for higher pressure units. Meeting the product objectives under such conditions can be challenging. Very often the cycle length is determined not by decline in conversion, but by failure to meet a product property such as sulphur content in the diesel fraction. Our catalysts exhibit an excellent nitrogen tolerance, resulting in very stable HDS and HDN activities throughout the cycle. The optimal catalyst or combination of catalysts depends on feed quality and available hydrogen . 7 Catalyst references Slovnaft a.s., Slovakia has purchased 190 tonnes of catalysts for their high pressure hydrocracker. The catalysts were purchased for their 3,400 MT/day unit, operating at 150 bar with a conversion at about 95%. This decision was taken based on experiences with excellent performance of Topsøe’s catalysts since 2005. The feed to the unit is Russian export blend. Preem Lysekil, Sweden has decided to follow a successful three-year TK-558 BRIM™ run of their 53.000 bpsd, 71 bar mild hydrocracker unit with a new load of Topsøe catalysts. This is due to needs for higher conversion when they are in VGO mode of this unit and improved cold flow properties of the diesel produced in the diesel mode. ENAP Refinerias Bio Bio, Chile has selected catalyst material from Topsøe for the first time to their high pressure hydrocracker. This 2,400 MT/day unit operates at 143 bar, aiming at a maximum mid-distillate yield at a net conversion of 70% based on volume. The processed feed is blends of HVGO and HCGO, and the feed nitrogen varies fromENAP Refinerias Aconcagua, Chile has purchased 224 tonnes of catalysts for their3, single-stage hydrocracker. The catalysts were purchased for 000 MT/day unit operating with a conversion at about 60%. The main objectives are high quality FCC feed and high quality product diesel. The processed feed is blends of HVGO and VGO. YPF, Argentina selected Topsøe hydrocracking catalyst system after a series of detailed pilot plant studies on actual feed and conditions. The main objectives for this full conversion 140 bar hydrocracker are increased diesel and kerosene yields with improved properties such as cloud point and cetane index. Murphy Meraux, LA, USA has awarded Topsøe for their hydrocracker train. This full
    • load of Topsøe hydrocracker and pretreatment catalysts for the high pressure, 2,450 psi, 32,000 bpsd hydrocracker aims at 41% conversion with the highest possible selectivity into low sulphur mid distillates. The processed feed is a blend of HVGO, LVGO and AG with a rather high Si contenttwo-reactor 142 bar 47,000 bpsd hydrocracker, aiming at a 55% conversion with good properties of the produced diesel. Most of the feed being processed is Russian VGO. contained herein is confidential; it may not be used for any purpose other than for which it has been issued, and may not be used by or disclosed to third parties without written approval of Haldor Topsøe A/S. Saras, Sarroch, Italy decided again to use Topsøe catalysts for their 60,000 bpsd mild hydrocracker. This unit, aiming at 40-50% conversion and 10 ppm sulphur in the diesel, requires the most stable catalyst system in order to be able to operate for more than one year. The feed to this 100 bar unit has an end-point as high as 630ºC MOL Szazhalombatta, Hungary decided again to purchase Topsøe hydrocracking and pretreatment catalysts for their 2010 turnaround in their 6,000 MTPSD MHC unit. The processed feed is blends of HVGO and HCGO, aiming at a conversion of more than 27% to high quality diesel. The unit operates at a pressure of 75 bar. Petro Piar, Venezuela has again, due to very difficult operating conditions of the U16 and an unpredicted short cycle, selected Topsøe hydrocracking catalysts for this major hydrocracking 55,000 bpsd U16, treating very heavy coker gas oil feed. .
    • REFERENCES: 1) introduction: Wikipedia free encyclopedia 2)catalysis of hydrocracking and hydrotreating: Colarando school of mines (hydroprocessing pdf) 3) Fundamentals of Petroleum Refining by PDHengineer.com 4)hydrocracking and hydrotreating catalysis applications: Oil Refinery Processes A Brief Overview Ronald (Ron) F. Colwell, P.E. 5)Images: THE END