CATALYTIC REFORMING Process,Catalysts and Reactors

Axens India Private Limited
(Private Limited Company formed under the
Companies Act, 1956)
CATALYTIC REFORMING
Process,Catalysts and Reactors
on
Petroleum Federation of India
Indian Oil Corporation Ltd. (Haldia Refinery),
&
Lovraj Kumar Memorial Trust
Mohan Lal
Catalytic Reforming
1

Introduction
World context:
High octane gasoline requirement
Catalytic Reforming
2

Introduction
World context:
Low sulfur content,
Low benzene content,
Limited aromatics content,
Limited olefins content,
No lead
Catalytic Reforming
3

Introduction
European Gasoline specifications trends
2000 2005 Soon*
Ultimate
Severity**
Sulfur, ppm max 150 50 10 5
Aromatics, vol% max 42 35 30 25
Olefins, vol% max 18 18 14 10
Benzene, vol% max 1 1 1 1
Oxygen, wt% max - 2.7 2.7 2.7
Vapor pressure, kPa
max
90 60 60 50
C5+ ethers, vol%*** 15 15 15 15
Lead, ppb max 5 5 5 5
RON/MON, min 95/85 95/85 95/85 95/85
* Assumed ** Projected final limits ≥ 2015 ***banned in several states of USA
Catalytic Reforming
4

Introduction
Gasoline Pool specifications
Bharat
III
Sulfur, ppm max 150
Aromatics, vol% max 42
Olefins, vol% max 21
Benzene, vol% max 1
Oxygen, wt% max -
Vapor pressure, kPa max 60
RON/MON, min 91/81
Catalytic Reforming
5

Introduction
New gasoline specifications require:
• Maintaining a high octane level
• Meeting reduced sulfur specifications
• Meeting reduced Aromatics and Benzene
specifications
Catalytic Reforming
6

Introduction
Constraints from straight run gasoline: Initial fractionation
of crude oils gives gasoline cuts with a low octane number
‣ Light gasoline (C5-C6) : RON between 60 and 70
‣ Heavy gasoline (C7-C10) : RON between 30 and 50
Refiners have to considerably improve the
quality of gasoline cuts to meet RON/MON
specifications
Catalytic Reforming
7

Introduction
RON/MON is increased by chemical transformation
• Light gasoline : Isomerization process
n-paraffins i-paraffins
Ex: n-Hexane (RON= 24.8) 2,2-DM Butane (RON=
91.8)
• Heavy gasoline: Catalytic Reforming process
n-paraffins, naphtens aromatics
Ex: Cyclohexane (RON = 83) Benzene (RON = 108)
Catalytic Reforming
8

Outline
• Fundamentals of Catalytic Reforming
• Objective
• Reactions – desirable and undesirable
• Process
• Semi Regenerative Reforming
• Dualforming
• Continuous Catalytic Regenerative Reforming
• Process Variables
• Reforming Catalyst
• Types
• Poisons
• Some Recent Advances in Reforming
• Update on CCR Technology / Catalyst
• Update on SR Technology/ Catalyst / Debottle-necking
Options
Catalytic Reforming
9

Fundamentals
Catalytic Reforming
10

Purpose of reformer
Purpose of reformer
• The purpose of Reforming process is to produce :
- high octane number reformate, which is a main component for motor m
fuel, aviation gasoline blending or aromatic rich feedstock.
- hydrogen rich gas
- Due to the nature of the reactions, reforming process produces also: a
LPG – FG – 600 psig steam with the waste heat boilers
Catalytic Reforming
11

Purpose of reformer
• Reformer feed is either:
- Low quality straight run naphtha
- or cracked naphtha, generally mixed with
straight run naphtha.
• Reformer feed pretreatment
Due to the presence of contaminants in all cases and to
the specific characteristics of cracked naphtha,
Naphtha Pretreating unit(s) is(are) ) always necessary.
Catalytic Reforming
12

Chemical Reactions
Catalytic Reforming
13

Chemical reactions
• Two types of reactions
involved in the Octanizing
process:
– Desirable reactions, , which
lead to a higher octane
number and to high purity
hydrogen production. They
are the reactions to
promote
– Adverse reactions, , which
lead to a decrease of
octane number and a
decrease in hydrogen
purity. They are the
reactions to minimize
RON
MON
• Cyclohexane = 83 77.2
• Methylcyclohexane = 74.8 71.1
• 1.3 dimethylcyclohexane = 71.7 71.
• Benzene = 114.8 > 100
• Toluene = 120 103.5
• m-Xylene
= 117.5 115.
RON:
MON:
Research Octane Number
Motor Octane Number
Catalytic Reforming
14

Desirable reactions with hydrogen production
• Naphthenes dehydrogenation
– Naphthenic compounds dehydrogenated into aromatics with production
on
of 3 moles of H2 per mole of naphthene
– Promoted by the metallic function
– Highly endothermic
– Thermodynamically favored by high temperature, low pressure and high
number of carbons
– Kinetically favored by high temperature, high number of carbon; not
affected by the hydrogen partial pressure
– At the selected operating conditions, reaction is very fast and almost
total
CH 2
CH
H C
2
CH 2
HC
CH
+ 3H 2
H C
2
CH 2
HC
CH
CH 2
Cyclohexane
CH
Benzene
Catalytic Reforming
15

Desirable reactions with hydrogen production
• Paraffin's dehydrocyclization
– Multiple step reaction
– Promoted by both acidic
and metallic functions
CH 3
CH 2
CH 2
CH 2
CH 2
CH 2
CH 3
CH
CH CH 2 2
CH CH 3 CH CH 2 3
+ H
2
– Kinetically favored by high
temperature, , and low
pressure
– Dehydrogenation step
becomes easier as paraffin
molecular weight increases,
but is competed
by hydro cracking
– At the selected operating
conditions, much lower
rate than that of
dehydrogenation
CH 3
CH
C H
7 16
H C 2
CH 2
CH 2
CH 2
CH 2
CH CH 2
CH 3
H C 2
C H
7 14
CH 2
CH 2
CH 2
CH 2
CH
Methylcyclohexane
CH 2
CH 2
CH CH3 CH 3
HC
CH
CH
CH
CH
C
CH 3
+ 3H 2
Catalytic Reforming
16

Desirable reactions with hydrogen production
• Linear paraffin's isomerization
– Promoted by the acidic function
– Slightly exothermic
– Fast
– Thermodynamically dependant on temperature; pressure has no
effect
– Kinetically favored by high temperature; not affected by the
hydrogen partial pressure
C H 7 16 C H 7 16
Carbon atom
C4
C5
C6
C7
C8
% Isoparaffin at
500°C
44 58 72 80 88
Catalytic Reforming
17

Desirable reactions with hydrogen production
• Naphthenes isomerization
– Desirable reaction because of the subsequent dehydrogenation of the
alkylcyclohexane into an aromatic
– Difficulty of ring rearrangement and high risk of ring opening (paraffin(
formation)
– At the selected operating conditions, theoretically low rate but
subsequent dehydrogenation shifts the reaction towards the desired
ed
direction
– Slightly endothermic
– Easier reaction for higher carbon number
RON
MON
• Ethylcyclopentane = 67.2 61.2
• Methylcyclohexane = 74.8 71.1
• Toluene = 120 103.5
Catalytic Reforming
18

Adverse reactions
• Hydrocraking
– Hydrocracking affects either
paraffins or olefins
– Promoted by both acidic
and metallic functions
– Favored by high temperature
and high pressure
– Exothermic
(risk of runaway reactions)
– At the selected operating
conditions, hydro cracking
reaction could be complete,
but is limited by kinetics
C H
7 16
C H
7 14
C H
4 8
(m)
+ H
2
+ H
2
(a)
(m)
C H
7 14
C H
4 8
C H
4 10
+
+ H
2
C H
3 8
Catalytic Reforming
19

Adverse reactions
• Consequences of cracking:
– Decrease of paraffins and increase of aromatics
proportion (i.e. increase in octane) in the reformate and a
loss of reformate yield
– Decrease in hydrogen production (cracking reactions
consume hydrogen)
– Increase of light ends production and low molecular
weight paraffins
Catalytic Reforming
20

Adverse reactions
• Hydrogenolysis
– Promoted by metallic function
– Favored by high temperature and high pressure
– Exothermic (risk of runaway reactions)
or
C H
7 16
+ H
2
CH 4
+
C H
6 14
C H
7 16
+ H
2
C H + 2 6
C H
5 12
Catalytic Reforming
21

Adverse reactions
• Hydrodealkylation
– Breakage of the branched radical of an aromatic ring
– Promoted by metallic function
– Favored by high temperature and high pressure
– Consumes hydrogen and produces methane
– But at the selected operating conditions, and with the selected catalyst,
this reaction is not significant
+ H
2
+ CH 4
Xylene
Toluene
+ H
2
+ CH 4
Toluene
Benzene
Catalytic Reforming
22

Adverse reactions
• Alkylation
– Addition of an olefin molecule on an aromatic ring
– Promoted by metallic function
– leads to heavier molecules which may increase the
end point of the product
– High tendency to form coke; ; must be avoided
CH 3
+ CH 2
= CH – CH 3
HC
Benzene Propylene Isopropylbenzene
CH 3
Catalytic Reforming
23

Adverse reactions
• Transalkylation (alkyl disproportionation)
– Dismutation of 2 toluene rings to produce benzene and xylene
– Promoted by metallic function
– Favored by very severe conditions of temperature and pressure
– At the selected operating conditions, and with the selected
catalyst, this reaction is negligible
+
+
Toluene
Toluene
Benzene
Xylene
Catalytic Reforming
24

Adverse reactions
• Coking
– Results from a complex group of reactions. Detailed
mechanism not fully known yet
– Linked to heavy unsaturated products (polynuclear(
aromatics)
and heavy olefins traces or diolefins present in the feed or in
CCR reactions
– Coke deposit reduces active contact area and reduces
catalyst activity
– Favored by low pressure
In Octanizing operating conditions, necessity of a
continuous regeneration to maintain a low level of
coke
Catalytic Reforming
25

Chemical reactions
– All these reactions occur in series and parallel to each other producing p
a
complicated reaction scheme. In n an effort to simplify the scheme
according to the reaction rates the main reactions take place in the
following order:
• 1st reactor
• 2nd and 3rd reactors
• 4th reactor
Dehydrogenation
Isomerization
Dehydrogenation
Isomerization
Cracking
Dehydrocyclization
Cracking
Dehydrocyclization
Catalytic Reforming
26

Catalyst Distribution
• Highly endothermic transformation
• Reaction rates vary widely
The overall amount of catalyst
needed for the transformation is distributed –
not equally – among several adiabatic reactors
in series with intermediary heaters providing
the required heat energy input
Catalytic Reforming
27

Temperatures and Compositions
inside Reactors
Reactor Temperature, °C
H1 R 1 H2 R 2 H3 R 3
T 0
T 0 -25
T 0 -50
Composition, Vol%
P 0 = 60
N 0 = 30
A 0 = 10
Aromatics
Naphthenes
Paraffins
Catalytic Reforming
R 1 R 2 R 3
Position in Reactor
28

Chemical reactions
– The catalyst distribution is:
• R1 = 10%
• R2 = 15%
• R3 = 25%
• R4 = 50%
REACTIONS
HEAT OF
REACTION
(1) KCAL/MOLE
RELATIVE RATE
(2) APPROX.
Naphthenes dehydrogenation - 50 30
Paraffin dehydrocyclization - 60 1 (base)
Isomerization: Paraffins + 2
Naphthenes + 4
3
Cracking + 10 0.5
(1) Heat of reaction < 0 = endothermic reaction.
(2) For pressure below 15 kg/cm2.
Catalytic Reforming
29

Reforming Processes
Catalytic Reforming
30

Fixed bed reformer
• The most frequent type of unit
• Current licensors
• Axens, UOP
• In the old days (Chevron, Amoco, Exxon,
Engelhard)
Interheater 1 Interheater 2
1 2 3
A
B
Separator
Catalytic Reforming
Feed
Recycle
Compressor
Fuel Gas
LPG
Stabilized
Reformate
C
31

Conventional Unit
1 2 3
Booster
Compressor
Separator
Hydrogen-
Rich Gas
Recontacting
Drum
Feed
Unstabilized
Reformate
Recycle
Compressor
Catalytic Reforming
32

Dualforming
Texicap+ RG682
1 2 3
C
C
R
R
X
R
e
g
e
n
C
2
Booster
Compressor
12b
Hydrogen
Rich
Gas
Recontacting
Drum
Feed
Packinox
Recycle
Compressor
Unstabilized
Reformate
• Last Reactor Catalyst Continuously Regenerated
• Provides excellent option for the revamp of existing SR reformers
Catalytic Reforming
33

Continuous Catalytic Regenerative
Reforming
Catalytic Reforming
34

Continuous Catalytic Regenerative
Reforming
Elutriator
Reduction
Chamber
LC
Upper Hoppers
LC
LC
LC
Upper
Surge
Drum
Lock
Hopper
Coke
Reactors R1 R2 R3 R4
Regenerator
Catalytic Reforming
FC
H 2
FC
H 2
FC
H 2
FC
• Catalyst Continuously Regenerated
N 2
N2
FC
Lower
Hopper
Lift
Pot
• With advanced catalysts longer catalyst life and less makeup
rates possible
35

Objectives of Regeneration Section
Recover initial catalyst activity
• Coke removal
• Metal redistribution &
chloride adjustment
• Catalyst drying
2 Burning zones
Oxychlorination
Calcination
Each zone independently optimized
Catalytic Reforming
36

RegenC
Combustion
Gas
from Dry Loop
Additional
Air
Spent Catalyst
Primary
Burn
Finishing
Burn
To Dry Burn
Loop
Burning with dry gas control:
%O 2 , temperature
Catalyst’s specific
area is maintained
Chloriding
Agent
+ water
Oxychlorination
Calcination Gas
Oxychlorination
Calcination
Regenerated Catalyst
To Effluent
Treatment
Oxychlorination control:
% O 2 , temperature
and moisture
Optimum Pt dispersion
Catalytic Reforming
37

RegenC Catalyst Regenerator
«Coked» Catalyst
Combustion
Gas Inlet
Primary Burning
Air Inlet
Combustion
Gas Outlet
Oxychlorination Outlet
Chloriding Agent
Inlet
Finishing Burning
Oxychlorination
Calcination
Calcination Gas
Inlet
Regenerated Catalyst
Catalytic Reforming
38

Processes Variables
Catalytic Reforming
39

• Pressure
• Temperature
• Space velocity
• Hydrogen partial pressure (H2/HC)
• Quality of the feed
• Operating Parameters Summary
Catalytic Reforming
40

Process variables
• Each of them can be fixed by the operator - within
the operating range of the equipment -
independently from the others
• For one set of independent variables, for same feed
characteristics, there is only one performance of the
unit i.e. one set of values for:
– Product yields
– Product quality (Octane)
– Catalyst stability (coke make)
Catalytic Reforming
41

Pressure
Catalytic Reforming
42

Pressure
• Pressure is the basic variable because of its
inherent effect on reaction rates
• Effect of pressure on reactions
– Low pressures enhance hydrogen producing reactions:
dehydrogenation, dehydrocyclisation, , coking
– Cracking rate is reduced
The lower the pressure, the higher the yields of
reformate and hydrogen for a given octane number.
But high coking rate (compensated by continuous
regeneration)
Catalytic Reforming
43

Pressure
• Average catalyst pressure used, close to last
reactor inlet pressure
• During transient conditions (start up,
shutdown, upsets) it is recommended to
increase the pressure to lower coke
formation
• Limits of operators action
– Pressure rise limited by equipments design pressure
– Pressure lowering limited by recycle compressor
design power and intake volume
Catalytic Reforming
44

Temperature
Catalytic Reforming
45

Temperature
• Most important and most used operating parameter with
space velocity
• Catalyst activity is directly related to reactor temperature. By
simply raising or lowering reactor inlet temperatures, operators
can raise or lower product quality and yields
• It is commonly accepted to consider the weight average inlet
temperature (WAIT)
WAIT =
( ) wt of catalyst R x Ti + ( ) x Ti2.... + ( )
1
1
wt Catalyst R2
Total wt of catalyst
wt Catalyst R 4
x Ti 4
Where
Ti1, Ti2, … are inlet temperature of reactors
(wt of catalyst R1)… are weight of catalyst in reactors
Catalytic Reforming
46

Temperature
• An increase of temperature (i.e. WAIT) has the following
effects:
– Increases octane
– Decreases the yield (of C5+ fraction)
– Decreases the H2 purity.
– Increases the coke deposit
• A slight increase of temperature (WAIT) through the life of
the catalyst makes up for this activity loss
• Larger and temporary changes in temperature are required:
– To change octane - at constant feed quality and quantity
– To change feed quantity and still maintain octane
– To change feed quality and still maintain octane
Catalytic Reforming
47

Space Velocity
Catalytic Reforming
48

Space velocity
• Weight hourly space velocity:
WHSV =
Weight of feed (per hour)
Weight of catalyst in reactors
• Liquid hourly space velocity:
LHSV
=
Volume of feed at 15°
C (per hour)
Volume of catalyst in reactors
• Linked to residence time of feed in the reactor and
affects the kinetics of the Reforming reactions
Space
velocity
residence
time
higher
severity
Octane increased
Lower reformate yield
Higher coke deposit
Catalytic Reforming
49

Space velocity
• Operators must bear in mind that each time
liquid feed rate is changed, a temperature
correction must be applied if octane is to be
maintained.
• Important recommendation
– Always decrease reactor inlet temperature first and
decrease feed flowrate afterwards
– Always increase feed flowrate first and increase
reactor inlet temperature afterwards
Catalytic Reforming
50

Hydrogen to hydrocarbon ratio
Catalytic Reforming
51

Hydrogen to hydrocarbon ratio
H Pure hydrogen (mole/hour ) in recycle
• H2/HC ratio: 2
=
=
HC
Naphtha flow rate (mole/hour )
H 2 HC
= R M x Y
F m
Where R is the recycle flow in Kg/h (or lb/h)
M is the recycle gas molecular weight
F is the feed rate in Kg/h (or lb/h)
m is the feed molecular weight
Y vol. fraction of H2 in the recycle gas
• The recycle gas MW is obtained by chromatographic
analysis, as well as the H2 vol. fraction (Y)
• The feed MW is obtained by chromatographic analysis
or by correlation from its distillation range and specific
gravity
Catalytic Reforming
52

Hydrogen to hydrocarbon ratio
• Operators can change the H2/HC ratio by lowering
or increasing the recycle compressor flow
• For a given unit, the amount of recycle is limited by
the recycle compressor characteristics (power,
suction flow)
• The H2/HC ratio has no obvious impact on the
product quality or yield
• But a high H2/HC ratio reduces the coke build up
• It is strictly recommended to operate with a H2/HC
ratio equal to (or higher than) the design figure
Catalytic Reforming
53

Feed quality
Catalytic Reforming
54

Feed quality Chemical composition
• Characterization of the feedstocks by:
• With a higher 0.85 N + A
– The same Octane content will be obtained at a lower severity
(temperature) and the product yield will be higher
– Or for the same severity (temperature), the Octane content will be
higher
– Higher naphtenic content. The T
endothermic reaction heat is
increased and the feed flow rate will be limited by the heater design
duty
• With lower 0.85 N + A
– Higher paraffin content. The hydrogen purity of the recycle gas
decreases and operation will be limited by the recycle compressor
capacity
• Impurities
0.85 N + A
– Temporary or permanent reduction of catalyst activity by poisons
contained in the feed
Catalytic Reforming
55

Feed quality Distillation range
• The feed distillation range is generally as follows:
• IBP (Initial Boiling Point) 70-100
°C
• EP (End Boiling Point) 150-180
180 °C
• Light fractions:
Cyclization of C6 more difficult than that of C7-C8
C8
The lighter the feed, the higher the required
severity for a given Octane
• Heavy fractions:
high naphthenic and aromatics content
Lower severity to obtain good yields
But polycyclic compounds which favor coke deposit
EP higher than 180°C are generally not recommended
Catalytic Reforming
56

Operating Parameters Summary
• Hereafter the theoretical effect on the unit performance of
each independent process variable taken separately:
Increased
RONC
Reformate yield
Coke deposit
Pressure
Temperature
Space velocity
H2/HC ratio
A + 0.85 N
Naphtha
Quality
End boiling point
Initial boiling point
Catalytic Reforming
57

Catalysts
Catalytic Reforming
58

Catalyst
The main characteristics of a catalyst other than its physical and
mechanical properties are :
• The activity
o catalyst ability to increase the rate of desired reactions
o Is measured in terms of temperature
• The selectivity
o Catalyst ability to favor desirable reactions
o Practically measured by the C5+ Reformate and Hydrogen
yields
• The stability
o Change of catalyst performance ( activity, selectivity )with
time
o Caused chiefly by coke deposit and by traces of metals in feed
o Measured by the amount of feed treated per unit weight of
catalyst. C5+ wt reformate yield is also an indirect measure of
the stability.
Catalytic Reforming
59

Catalyst
• Catalyst
• Chlorinated gamma alumina with nanao
particle of Pt
• The chlorinated gamma alumina has too
strong acid sites
• The Pt promotes hydrogenolysis of
+ H2
Pt
Catalytic Reforming
60

Catalyst
• In the 90’s Procatalyse (now Axens)
launched promoted Pt/Re catalyst
• RG 582
• Then RG 682 in 2000
• The promoter provides two benefits
• Reduced hydrogenolysis by a modification
of the metallic cluster
• Lower the number of the strongest acid
sites
Catalytic Reforming
61

Catalyst
• The stability of Pt has been improved by
addition of promoters (Re, Ir)
• The hydrogenolysis of Pt has been
reduced by addition of promoters
• The acidity of the chlorinated gamma
alumina has been tuned by addition of
promoters
Catalytic Reforming
62

Catalyst
• To improve the catalyst stability the Pt sintering has to be
hindered
• Addition of promoters
• Rhenium or Iridium
• Explanation
• Re and Ir is alloyed with Pt the “boiling point” of Pt is increased
Sintering reduced
1.00
0.75
Pt accessible
Pt Total
0.50
• Operating conditions
• T = 650°C
• H2 = 2 000 L/kg/h 0.25
Catalytic Reforming
Pt + Re
Pt
0 10 20 30 40 50
Time, hours
63

• Reforming catalysts are bimetallic catalyst consisting of
platinum plus promoters on an alumina support, Rhenium and
Tin being essentially one of the promoter besides the others.
• The main features of these catalysts are :
o High purity alumina support - High mechanical resistance
o Platinum associated with Rhenium - high stability &
selectivity
o Platinum associated with Tin – high selectivity
o High Regenerability
Catalyst
• The combination of these qualities give the following
advantages:
o High Reformate yield
o High hydrogen yield
o High on - stream factor
o Low catalyst inventory
Catalytic Reforming
64

Catalyst
‣Platinum (Pt) plus other promoter(s) impregnated on to
gamma alumina containing around 1% wt chloride to
provide acidity.
‣Since 1967, bimetallic catalysts have been widely used.
‣The second metal comes from the group
Rhenium (Re)
Tin (Sn)
Iridium (Ir)
Germanium (Ge)
Catalytic Reforming
65

WHICH METAL COMBINATION TO CHOOSE
‣Depends on what you want from the catalyst - "THE
OBJECTIVES"
‣Stability / cycle life
‣Selectivity towards
hydrogen (H 2
)
liquid reformate (C 5
+ reformate)
benzene yield in C 5
+ reformate
Catalytic Reforming
66

Stability
• Normal causes for catalyst ageing/deactivation
– metal sintering
– temperature
– metallic phase
– presence of chloride
– deposition of coke on metal and acid sites
Coking effect can be split
– 1. Degree of poisoning of deposited coke
– 2. Relative coking rate
Catalytic Reforming
67

SELECTIVITY
• Desired yields are:
– hydrogen
– C 5 + reformate
– low benzene
• Benzene
– yield can be minimised by pre-fractionating the
precursors (MCP, CH, nC6P) which are present in the
fraction boiling between 70 to 85°C
– benzene is also produced by the hydrodealkylation of
alkyl benzenes
• Loss of desired yields is caused by cracking
– hydrocracking involving the metal plus acid sites
– hydrogenolysis involving the metal in the presence of
hydrogen
Catalytic Reforming
68

SUMMARY - EFFECT OF SECOND METAL
• Tin and Germanium
– increases selectivity towards desired products
– no stability benefit
• Rhenium and Iridium
– increase stability
– no major effect on yield selectivity
• Other effects such as regenerability and tolerance to feedstock
impurities has led to the PtRe combination being preferred catalyst
Catalytic Reforming
69

TRI METALLIC CATALYST
• RG 582 introduced 1994
• Third metal moderates hydrogenolysis activity to
between that of balanced PtRe and PtSn
• Desired yields increased
– Hydrogen by 0.1 to 0.15wt%
– C 5 + by around 1 wt%
• Stability studies in pilot plant show 93 - 100% of
balanced bimetallic catalyst, but in commercial units
>100% is commonly seen.
Catalytic Reforming
70

Pilot test results
Low pressure pilot test
Selectivity
C5+ yield
Axens New series
- Multi Promoted Catalyst
- Reduced Pt content
Previous Generation
- Bi-promoted catalyst
- High Pt content
- Tri-promoted catalyst
- Reduced Pt content
Stability (time)
Selectivity & stability improvement
Catalytic Reforming
71

Catalysis Mechanism
• The catalyst affects reaction rates through its two different
functions/type of sites:
o Metallic, and
o Acidic
Different types of reactions are promoted by these sites as:
o Dehydrogenation Metallic
o Dehydrocyclisation Metallic + Acidic
o Isomerisation Metallic + Acidic
o Hydrogenolysis Metallic
o Hydrocracking Metallic + Acidic
Catalytic Reforming
72

Catalysts Poisons
Catalytic Reforming
73

Catalyst Contaminants
Temporary poisons
• Which can be removed and the proper Activity and Selectivity
of catalyst is restored.
• The most common temporary poisons ( inhibitors ) are:
o
o
o
o
o
Sulphur
Organic nitrogen
Water
Oxygenated organics
Halogens
Catalytic Reforming
74

Catalyst Contaminants (Contd…)
Permanent poisons –
Which induce a loss of activity which can not be restored.
Main permanent poisons are
• Arsenic
• Lead
• Copper
• Iron
• Nickel
• Chromium
• Mercury
• Sodium
• Potassium
Catalytic Reforming
75

Reactor Types
Catalytic Reforming
76

Typical Axial Fixed-Bed
Reactors
Catalytic Reforming
77

Typical Radial Fixed-Bed
Reactor
Bolted metal shroud and cover
Catalyst
Dead Space
The design of the upper part of
the reactor was made to take
into account
- density change (settling)
- possible by-passing of catalyst
- space for mechanical assembly
Catalytic Reforming
78

Typical Radial CCR Reactor
Feed
Catalyst
Effluent
Catalytic Reforming
79

Texicap TM
A New Concept of Radial Reactor
Internals
A Flexible Flow-guide that
molds to the shape of the top of the bed
Catalytic Reforming
80

Typical Radial Fixed-Bed
Reactors
BEFORE
Bolted metal shroud and cover
Catalyst
Dead Space
The design of the upper part of
the reactor was made to take
into account
- density change (settling)
- possible by-passing of catalyst
- space for mechanical assembly
Catalytic Reforming
81

Modifying Radial Fixed-Bed
Reactors with Texicap
Catalyst
Dead Space
BEFORE
AFTER
Gained
with
Texicap
Catalytic Reforming
82

Catalyst Sampler
Refilling
Sampling Box
Draining
N 2
ATM FL
Handling Head
Receiving Pot
Catalytic Reforming
Drain
83

Catalytic Reforming
84