1. RAJIV GANDHI INSTITUTE OF PETROLEUM TECHNOLOGY
By: Kaneti Pramod (e11-0031)
Gogineni Sai Srujan(e11-0024)
2. .CATALYSIS OF HYDROTREATING AND
DR. Alok Kumar Singh sir
DATE OF SUBMISSION : 02-03-2012
By: Kaneti Pramod (e11-0031)
Gogineni Sai Srujan(e11-0024
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
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
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
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
5. 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.,
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.
6. Table of Content:-
1. What is catalysis ________________________________________1
2. Catalysis and reaction energetic_____________________________2
3. Types of catalysis ________________________________________3
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
7. 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
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
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.
8. 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).
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 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.
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
9. 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.
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
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.
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
10. chemistry, analytic chemistry, inorganic chemistry, chemical engineers and surface
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.
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
11. 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.
12. ―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.
of the dual mechanism involves adsorption of a paraffin molecule
to a metal site, followed by reversible dehydrogenation to form an olefin. In
the olefin migrates to an acid site, where it reacts with a proton to
form a carbenium ion.
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
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).
13. 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
14. 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
15. 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
• 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
16. 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
• 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:-
17. May use separate reactors with desulfurization &
olefin saturation in 1st
reactor & hydrocracking in 2nd
» 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
18. • Naphtha Hydrotreating– Primary objective is to remove sulphur contaminant for
downstreamprocesses; typically < 1wppm
• Gasoline Hydrotreating– Sulfur removal from gasoline blending components to meet recent
• 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
– Aromatic saturation improves FCC feed ―crackability‖
– Improved H/C ratios increase FCC capacity and conversion.
19. 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.
Feedstocks desired products process objectives.
Napthas Catalytic reformer feed. Removal of S,N,Olefins.
Atmospheric gas oils Diesel Removal of S,aromatics and
Jet Removal of S and aromatics.
Ethylene feedstock Removal of aromatics.
Vaccum gas oils. LSFO Removal of S
FCC feed Removal of S,N and metals.
Diesel Removal of S and aromatics
Kerosene/jet Removal of S and aromatics.
20. LPG Hydrocracking
Ethylene feedstock Removal of aromatics
Lube oil base stock Removal of S,N and
Residuum LSFO Removal of S
FCC feedstock Removal of S,N CCR and
Coker feedstock Removal of S,CCR and
Characteristics of petroleum products.
Characeristics of petroleum processing
Crude oil Hydrogenation
Average carbon no. (atoms per molecule)
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
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
21. Sources of hydrogen:-
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).
-pressure swing adsorption
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.
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.
-more removal of heteroatoms in subsequents
3. Selective catalysts for sulphur removal without olefin saturation
a) Maintaining high octane rating
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
Types of 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.
23. Distillate Hydrotreating:-
Product Information - Distillate Hydrotreating
Catalyst Type/Applications Description
NiMo - Distillate
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.
stability in this severe
NiMo - Distillate
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.
24. Demonstrates exceptional
stability in this severe
CoMo - Distillate
CRITERION DC-200 is a high
activity, high stability Cobalt
CoMo - ULSD
is a high activity
catalyst for the
CoMo - Distillate
High activity, low
density catalyst for
production of Low
Sulfur Diesel (<50-
CoMo - ULSD
catalyst ideal for
producing ULSD at
when it is critical to
addition to the feed.
CoMo - ULSD Ideal catalyst for producing
25. ASCENT DC-
production ULSD at low-to-moderate
especially when it is critical to
limit hydrogen addition to the
ASCENT Catalyst Technology,
Criterion’s latest innovation,
performance by expanding
promoter metal utilisation
through an enhanced catalyst
NiMo - Distillate
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.
high activity catalyst for
production of Ultra Low
Sulfur Diesel (<10ppm) at
26. 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
27. 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 ,
28. 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
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
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.
29. 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
KF 772KF 772 STARS™ is a high activity desulfurization catalyst in the STARS™ catalyst
30. 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
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.
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
31. 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
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.
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.