PRESENTATION ON

CATALYTIC REFORMING UNIT

UNIT SCOPE OF THE UNIT

NSU Feed preparation for HTU

HTU Removal of Sulphur, Nitrogen, Oxygen from feed

of CRU .

CRU For production of high octane reformate (MS

component)

CCRU For burning coke from CRU catalyst.

N2 To produce pure N2 for units.

Ammonia To improve Hydrogen purity of recycle gas.

Refrigeration

HYDROTREATER UNIT( UNIT-14) Catalysts used in hydrotreater : LD-145 1.9 M3

HR 348 19.1 M3

TO PROTECT THE REFORMER CATALYST THE FEED HAS TO

BE PRETREATED IN ORDER TO ELEMINATE THE FOLLOWING

POISONS:

S, N2, H20 , DIOLEFIN, ARSENIC AND METALS

BY HYDROREFINING REACTIONS WHERE MERCEPTANS,

SULPHIDES AND DISULPHIDES EASILY REACT LEADING TO

CORRESPONDING SATURATED AND AROMATIC COMPOUND

R-SH + H2 -----> RH +H2S,

R-S-R’ + 2H2 ------> RH +R’H +H2S R-NH2 + H2 -----> R-H + NH3

Sulfur combined into cycles of aromatic structure, like thiophene, is

more difficult to eliminate.

+ 4H2 C4 H10 + H2S

S

Thiophene De-NITRIFICATION:Nitrogen compounds inhibit considerably the acidic function of the reforming catalyst. They are eliminated by production of ammonia. The nitrogen compounds of SR naphtha are methylpyrol and quinoline.

HC CH

+ 4H2 C5H12 + NH3

HC C-CH3N

Methyl pyrrol n-Pentane Ammonia

Quinoline Benzene Propane

Nitrogen elimination is practically complete. The total Nitrogen content in the product is less than 0.5 PPM

+C3H8+NH3

HC

HC

HC

HC

HC

HC

HC

C

N

CH

CH

CH

CH

CH

CH

+ 5H2

CH

HYDRO-DEOXYGENATION:HYDRO-DEOXYGENATION:

Oxygen or oxygen compounds modify the acidic

function of the reforming catalyst. They are eliminated

by production of water. The oxygen compounds of

straight-run are peroxides and phenols.

Oxygen is almost completely transformed into water.

HC

HC

HC

OH

CH

+ H2

HC

HC

CH

HC

CH

CH

+ H2O

CH

Phenol Benzene

HYDROTREAER UNIT( UNIT-14)

HYDROGENATION REACTION CONVERTS THE DIOLEFINS,

OLEFINS TO SATURATED COMPOUNDS

THE ARSENIC AND METAL COMPOUNDS ARE ABSORBED ON

THE CATALYST ( NICKEL AND MOLYBDENUM CATALYST)

Operating conditionsNHTU : ATTRIBUTES UNITS Pretreater Feed MT/hr 49Reactor inlet tempearture 0 C 291Delta T 0 C 2.1Stripper bottom sulphur ppm 0.25 Moisture ppm 5-6

OBEJECTIVE OF CRU

To produce lead free Motor Sprit from Mathura Refinery. The

purpose of CCRU type or Reforming Unit is to produce High

Octane reformate as component of lead free Motor Spirit.

Design Capacity: 0.466 MMT/Year based on 8000 hrs/y

Over Design Factor 120% of Design

Turn Down Capacity 60% of Design

CATALYTIC REFORMING

BY PRODUCTS

H2 RICH CRU GAS USED AS MAKE-UP FOR HYDROTREATING, AND TO PRODUCE H2 THROUGH PSA -140 MAKING MORE ECONOMIC VIABLE PROCESS.

LPG (NOT GENERATED AT PRESENT)

CATALYST (CR 201) CHARACTERISTICS

THE OCTANENISING CATALYST CR-201 IS MULTIMETALLIC CATALYST CONSISTING OF PLATINUM PLUS METAL PROMOTORS TIN ON AN ALUMINA SUPPORT

HIGH PURITY ALUMINA SUPPORT HAVING STRONG RESISTANCE TO ATTRITION

HIGH STABILITY AND SELECTIVITY DUE TO Pt AND SnHIGH REGENERABILITY IDEALY SUITED FOR CCRUHIGH REFORMATE YIELDHIGH HYDROGEN YIELDHIGH STREAM FACTOR LOW CATALYST INVENTORY

CATALYST CONTAMINANTS

TEMPORARY POISONS ARE THOSE WHICH CAN BE REMOVED FROM CATALYST WITHOUT SHUTDOWN. THEY ARE SULFUR, ORGANIC NITROGEN, WATER AND OXYGENATED ORGANICS AND HALOGEN.

PERMANENT POISONS ARE THOSE WHICH INDUCE A LOSS OF CATALYST ACTIVITY WHICH CAN NOT BE RECOVERED EVEN WITH THE REGENERATION AND MAY BE SO SEVERE THAT THE CATALYST MAY BE REPLACED.

THE MAIN PERMANENT POISONS ARE ARSENIC, LEAD , COPPER , IRON , NICKEL AND CHROMIUM

OCTANE NUMBER OF HYDROCARBONS

OCTANE NUMBER IS A MEASUREMENT OF ANTI-KNOCK CHARACTERISTICS OF FUELS.

AMONG THE SAME CARBON NUMBER COMPOUNDS THE ORDER OF RON (RESEARCH OCTANE NUMBER) IS –PARAFFINS < NAPHTHENES < AROMATICS.

BRANCHED PARAFFINS ALSO HAVE HIGH OCTANE. IT INCREASES WITH DEGREE OF BRANCHING.

THEREFORE OCTANE NUMBER OF NAPHTHA CAN BE IMPROVED BY REFORMING THE HYDROCARBON MOLECULE (MOLECULAR REARRANGEMENT). SUCH REARRANGEMENT TAKES PLACE IN REFORMING REACTORS IN PRESENCE OF CATALYST BY WAY OF NUMBEREOUS COMPLEX REACTIONS.

OCTANE NUMBER OF VARIOUS HYDROCARBONS

n Butane 94.0 I Butane 102.0 n Pentane 61.8 l Pentane 93.0 n Heptane 0.0 l octane 100.0

Toluene 120

INDEX = A+0.85N

THE HIGHER THIS INDEX, THE LOWER THE SEVERITY OF OPERATION TO MEET THE SAME PRODUCT SPECIFICATION. THE LOWER THIS INDEX (I.E. HIGHER THE PARAFFINS) THE HIGHER THE SEVERITY OF OPERATION TO MEET THE SAME PRODUCT SPECIFICATIONS, AS THE

DEHYDROCYCLIZATION OF PARAFFINS BECOMES IMPORTANT.

REACTIONS IN CATALYTIC REFORMING

FOLLOWING ARE THE MOST PREVALENT MAIN REACTIONS IN CATALYTIC REFORMING

DEHYDROGENATION OF NAPHTHENES TO AROMATICS.

ISOMERISATION OF PARAFFINS AND NAPHTHENES.

DEHYDROCYCLISATION OF PARAFFINS TO AROMATICS.

HYDROCRACKING OF PARAFFINS TO LOWER MOLECULAR WEIGHT COMPOUNDS.

HYDROCRACKING

RUPTURE OF CARBON TO CARBON BOND WITH REVERSIBLE FORMATION OF LOWER MOLECULAR WEIGHT PARAFFINS.RCH2 CH2 C H3 + H2 ----> RH + CH3 CH2 CH3

N – PARAFFIN PARAFFIN

HYDROCRACKING IS EXOTHERMIC. THESE REACTIONS ARE UNDESIRABLE DUE TO DECREASE IN

REFORMATE YIELD. FAVOURED BY INCREASE IN TEMPERATURE AND PRESSURE. HYDROCRACKING PRODUCE COKE PRECURSOR AND

REDUCE THE CATALYST ACTIVITY. REACTIVITY OF PARAFFINS HYDROCRACKING INCREASE WITH

CARBON CHAIN.

MAIN OCTANIZING REACTIONSTHE MAIN OCTANIZING REACTIONS TAKE PLACE IN THE VARIOUS REACTORS IN THE FOLLOWING ORDER,

1ST REACTOR 2ND REACTOR 3RD REACTOR

DEHYDROGENATION DEHYDROGENATION CRACKINGISOMERIZATION ISOMERIZATION -

- CRACKING -- DEHYDROCYCLIZATION DEHYDROCYCLIZATION