Catalytic Reforming

Low Octane Rating of Gasoline vs. Demand Noise and Loss in Energy Solutions to the Problem Addition of High O.N. Compounds Tetra Ethyl Lead (TEL) Oxygenates (MTBE & TAME) Alteration of the Chemical Composition Thermal Reforming Catalytic Reforming

Catalytic Reforming

Under Supervision of

Dr El-Shazly Salem

Eng Hossam Hosny Mohamed El-Ghareeb

Eng Mohamed Mohamed Refaat Ibrahiem

Eng Mahmoud Ibrahiem Mohamed Mohamed

Eng Mustafa Mahmoud Abd-ALLAH

Eng Mohamed Saied Abu Basha

Antiknock Quality Problem

 Low Octane Rating of Gasoline vs Demand

 Noise and Loss in Energy

 Solutions to the Problem

 Tetra Ethyl Lead (TEL)

 Oxygenates (MTBE & TAME)

 Thermal Reforming

 Catalytic Reforming

Catalytic vs Thermal Reforming

Feed Treatment By Hydrogen

The Catalytic Reforming Process

 Aims of Process:

 Min Capacity to form Gums …… By Saturation

 Production of Hydrogen for other Processes

 Production of BTX for the Petrochemical Industry

Feed To Catalytic Reforming

 Sources of Feed:

Two Typical Feeds Composition

Paraffinic (Arabian Light) Naphthenic(Nigeria)

Total Change to The Feed

Catalytic Reforming Product

 Relation between ON and Reformate Yield

2.37 1.97 8.42 4.91 1.04 0.28 0.02

21.01

0.57 3.88 5.66 10.92 6.07 1.3 0.35 0.02

28.77

0.1 0.16 0.35 0.44 0.08 0 0

1.13

0 0.19 0.4 0.34 0 0 0

0.93

2.34 14.16 26.28 21.08 4.76 0.55

69.17

3.98 8.35 25.83 33.13 22.46 5.11 0.57

100

nP: normal paraffins iP: branched paraffins P: total paraffins.

O: olefins N: naphthenes A: aromatics

Reformate Composition

Catalytic Reforming Technology

 Non-Regenerative …… Replacement (months)

 Semi-Regenerative …… Shutdown (years)

 Regenerative (Cyclic) …… Switching (days)

Fixed-Bed Technology

 Type of Reactors

Fixed-Bed Technology

 Reactor Configuration

Fixed-Bed Technology

 Temperature Variation in Reactors

Fixed-Bed Technology

 Variation in Effluent Composition

Fixed-Bed Technology

 The First Technique to be used (used by UOP)

 High Pressures (above 35 bars)

 Catalyst Life of 10 months

 Catalyst is replaced & Regenerated off-site

 Low Severity & High Pressures…… led to switching

to the (semi-regenerative) Technique

Fixed-Bed Technology

 Catalyst life of 7-10 years

 Regeneration causes the Total Shutdown of System

 Regeneration is carried out inside the system

Fixed-Bed Technology

 Semi-Regenerative (SR) Technique

Fixed-Bed Technology

 Shutting Down is avoided by an Extra Reactor

 Complex Valve System, Reactor Central Position

 Modes of Run: (Cyclic) or (Swing)

 Catalyst Life of about 5-15 days

 Higher ON for the same Yield, and vice versa

 5 Units higher ON than Semi-Regenerative

 “Ultraforming” and EXXON “Powerforming”

Fixed-Bed Technology

Moving-Bed Technology

 Higher ON even from difficult feeds

 All-year run, producing the H2 that refineries need

 Catalysts are less stable over time but more selective making it possible to improve yields

 Lower recycle rates, which improve yields and reduce operating costs

 Lower operating pressures which favors reformate yields and hydrogen production

Moving-Bed Technology

 “One on the top of the other”, which is carried out by UOP

 “Side by Side”, which is carried out by IFP

Moving-Bed Technology

 UOP: “CCR Platformer®”

Moving-Bed Technology

 IFP: “Octanizer®”

Fluid-Bed Technology

under-reforming

desired product

Reactions & Thermodynamics

Dehydrogenation of Naphthenes

 Main Reaction in producing Aromatics

 Very Rapid, goes to Completion,& Highly Endothermic

 Favored by High Temperatures & Low Pressures

 Naphthenes is the most desirable component for the production of H2 & the Speed of Reaction

 Isomerization of Alkylcyclopentane to Alkylcyclohexane before converting to Aromatics

 Possible Paraffin Formation, for ring rearrangement

 Thermodynamic Equilibrium favors isomer formation, which increases the ON

Dehyrocyclization of Paraffins

 The most difficult Reaction to promote

 Consists of molecular rearrangement of P to N

 High M.wt Paraffins are easier to Cyclize & Crack

 Favored by Low Pressures & High Temperatures

Hydrocracking of Paraffins

 Not Desirable as it consumes hydrogen and reduces liquid product

 Favored by High Temperatures & High Pressures

 Concentrates Aromatics and increases ON

Dealkylation of Aromatics

 Shortening of the Alkyl Group

 Removal of the Alkyl Group

 Favored by High Temperature & High Pressures

 Long side chains lead to similarity to paraffin cracking

Reaction Thermodynamics

Heats of Reactions

Catalytic Reforming Catalyst

Catalytic Reforming Catalyst

 Consists of two metals:

 Pt/Re for Semi-Regenerative Processes

 Pt/Sn for moving-Beds

 Achieving this combination is of the manufacturers’secret

 Metal Site (Pt) for Hyrdogenation & Dehyrogenation

 Acid Site (Alumina), for Isomerization

Catalytic Reforming Catalyst

Effects of Platinum Content in the

Catalyst Structure

and deactivation

operations (100 ON from low Naph Feeds)

Hydrogen Action

Hydrogen Action

Factors Affecting Catalyst

Deactivation

 Hydrogen Partial Pressure

Factors Affecting Catalyst

Deactivation

 High Temperatures increases Coke Deposition on the Catalyst ……… (Olefins are Coke precursors)

 High Temperatures increases the rate of

Graphitization of Coke

 Coke growth occurs mainly on the Support

 Temperature doesn’t change the coke location,

whether on the Support or on the Metal

Factors Affecting Catalyst

Deactivation

 Nature of Feed:

 Heavier Cuts produce more Coke

Factors Affecting Catalyst

Deactivation

feed

requirements for the same ON

Factors Affecting Catalyst

Deactivation

Mechanism of Coke Formation

 Series of Dehydrogenation & Fragmentation leading

to the formation of (C) atoms

 Polymerization

 Polymerization (Ex: Cyclopentane to naphthtalene)

Poisoning of Reforming Catalyst

 Adsorbed at very low gas conc & form very stable Poisonous species

 Sulfur limits in feed:

 Monometallic (Pt/Al2O3) ………below 20 ppm

 Bimetallic (Re-Pt/Al2O3) ……… below 1 ppm

 Higher Re/Pt Ratio is more sensitive … below 0.5 ppm

 ↑Increasing Acidity which affects Dehydrogenation

 ↑Accelerates Cat Deactivation, Inhibits Aromatics

Poisoning of Reforming Catalyst

 Poisoning by Nitrogen:

 In the form of organic Comp (decom to Ammonia)

 ↑Inhibits Acidity with no effect on Dehydrogenation

Catalyst Regeneration

 Mechanism: Catalytic Hydrogenation Reaction

 Temperature Effect:

 The Carbon remaining is Decreased

 Activity for Benzene Hydrogenation is Increased

 Time Effect:

 The Carbon remaining is Decreased

 Carbon deposits become more & more Dehydrogenated

Catalyst Regeneration

1 Burning Coke on (Pt), for high H2 content in Coke

2 Burning Coke on Support, for lower H2 content

3 Burning Coke on the most distant location from (Pt),

for very poor H2 content in Coke

 Lower Temperature is for Higher Metal/Acid ratio

Parameters Controlling the Catalytic

Reforming Process

 Temperature Effect

Parameters Controlling the Catalytic

Reforming Process

 Continue Temperature Effect

Parameters Controlling the Catalytic

Reforming Process

Parameters Controlling the Catalytic

Reforming Process

 Pressure Effect

Parameters Controlling the Catalytic

Reforming Process

 Definition

 Types:

 LHSV = (vol feed/hr)/(vol Catalyst) = hr -1

 WHSV = (weight feed/hr)/(weight Catalyst) = hr -1

 No effect on Aromatization & Isomerization for high rates (reach equilibrium)

 A compromise between Hydrocracking &

Dehydrocyclization shoul be carried out

Parameters Controlling the Catalytic

Reforming Process

 Continue Space Velocity Effect

Parameters Controlling the Catalytic

Reforming Process

 Feed Range Effect

Parameters Controlling the Catalytic

Reforming Process

 Type of Feed Effect

Parameters Controlling the Catalytic

Reforming Process

 Advantage of increasing H2/H.C (decreasing Coke)

 Disadvantage of increasing H2/H.C (decreasing

aromatization & increasing Hydrocracking)

 H2/H.C is maintained by the use of recycle

Operating Condition for Present-Day

Processes