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 


2

Introduction 

World context: 

Low sulfur content, 

Low benzene content, 

Limited aromatics content, 

Limited olefins content, 

No lead 


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 


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 


5

Introduction 

New gasoline specifications require: 

• Maintaining a high octane level 

• Meeting reduced sulfur specifications 

• Meeting reduced Aromatics and Benzene 

specifications 


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 


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) 


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 


9

Fundamentals 


10

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 


11


• 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. 


12

Chemical Reactions 


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 


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 


15


• 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 


16


• 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 


17


• 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 


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 


19


• 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 


20


• 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 


21


• Hydrodealkylation 

– Breakage of the branched radical of an aromatic ring 


– 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 


22


• Alkylation 

– Addition of an olefin molecule on an aromatic ring 


– 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 


23


• Transalkylation (alkyl disproportionation) 

– Dismutation of 2 toluene rings to produce benzene and xylene 


– 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 


24


• 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 


25


– 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 


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 


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 


R 1 R 2 R 3 

Position in Reactor 

28


– 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. 


29

Reforming Processes 


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 


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 


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 


33

Continuous Catalytic Regenerative 

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 


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 


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 


Calcination Gas 


Calcination 

Regenerated Catalyst 

To Effluent 

Treatment 

Oxychlorination control: 

% O 2 , temperature 

and moisture 

Optimum Pt dispersion 


37

RegenC Catalyst Regenerator 

«Coked» Catalyst 

Combustion 

Gas Inlet 

Primary Burning 

Air Inlet 

Combustion 

Gas Outlet 

Oxychlorination Outlet 

Chloriding Agent 

Inlet 

Finishing Burning 


Calcination 

Calcination Gas 

Inlet 

Regenerated Catalyst 


38

Processes Variables 


39

• Pressure 

• Temperature 

• Space velocity 

• Hydrogen partial pressure (H2/HC) 

• Quality of the feed 

• Operating Parameters Summary 


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) 


41

Pressure 


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) 


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 


44

Temperature 


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 


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 


47

Space Velocity 


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 


49


• 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 


50

Hydrogen to hydrocarbon ratio 


51


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 


52


• 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 


53

Feed quality 


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 


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 


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 


H2/HC ratio 

A + 0.85 N 

Naphtha 

Quality 

End boiling point 

Initial boiling point 


57

Catalysts 


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. 


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 


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 


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 


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 


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 


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) 


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 


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 


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 


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 


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. 


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 


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 


72

Catalysts Poisons 


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 


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 


75

Reactor Types 


76

Typical Axial Fixed-Bed 

Reactors 


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 


78

Typical Radial CCR Reactor 

Feed 

Catalyst 

Effluent 


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 


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 


81

Modifying Radial Fixed-Bed 

Reactors with Texicap 

Catalyst 

Dead Space 

BEFORE 

AFTER 

Gained 

with 

Texicap 


82

Catalyst Sampler 

Refilling 

Sampling Box 

Draining 

N 2 

ATM FL 

Handling Head 

Receiving Pot 


Drain 

83


84

CATALYTIC REFORMING Process,Catalysts and Reactors

Create successful ePaper yourself

Delete template?

Save as template?