C2PT Catalyst Process Technology

Summary of design, operation, technology

Ethane usually recovered from natural gas fields mainly USA

Propane/butane recovered from gas fields middle east, Texas etc. Kuwait has a large butane recovery system. Also can come from LNG plants

Refinery naphtha / condensate C5 to C7 paraffin based low octane naphtha from refineries also from natural gas / oil well head production

Light and heavy gas oils refinery based (200 to 350°C) AGO and (350 to 550 °C) VGO

The more paraffinic the feedstock the higher the ethylene yields and the greater the value of the co-products

Sulfur + Cracks in furnaces to give H2S and COS. Mercaptans in C3/C4 cuts,

RSH and thiophenes in gasoline, benzothiophenes in fuel oil Arsenic

+ Organic or arsine + Makes arsine in the furnaces and some remains as organic

Mercury + Metallic / organic + Decomposes to metallic some remains as organic

Ballast water + Sea water from shipping feed stock

Metals + Nickel, sodium, vanadium, iron from heavy feedstocks

FCCU off gas (gas compressor suction, developing trend) + NOx, H2S, amines, SbH3, As , COS, O2, CO2 plus others

Feedstock West Europe

USA Japan World

Ethane 8 57.5 30.5

LPG 11 19 7.5 11

Naphtha 69 9.5 92.5 49

Gas Oil 12 14 8.5

Others 1*

Figures as wt% * Ethanol Brazil and India and Coal based gases Poland

PRODUCTS FEEDSTOCKEthane Propane Butane Naphtha Atm Gas

OilVGO

Hydrogen (95%) 8.8 2.3 1.6 1.5 0.9 0.8

Methane 6.3 27.5 22 17.2 11.2 8.8

Ethylene 77.8 42 40 33.6 26 20.5

Propylene 2.8 16.8 17.3 15.6 16.1 14

Butadiene 1.9 3 3.5 4.5 4.5 5.3

Other C4’s 0.7 1.3 6.8 4.2 4.8 6.3C5 to 200C Gasoline 1.7 6.6 7.1 18.7 18.4 19.3

Benzene 0.9 2.5 3.0 6.7 6.0 3.7Toluene 0.1 0.5 0.8 3.4 2.9 2.9

C9 aromatics - - 0.4 1.8 2.2 1.9Non aromatics 0.7 3.6 2.9 6.8 7.3 10.8

Fuel Oil - 0.5 1.7 4.7 18.1 25

Paraffin C7H16

Primary Cracking C3H8 + 1-C4H8

Dehydrogenation C7H14

Cracked Products

Butadiene C4H6

Secondary Cracking

Propylene C3H6

Propyne C3H4

CH4+ C2H4 2C2H4

Acetylene C2H2

Cyclo additions and Dehydrogenation give aromatics pyrolysis tar and coke

Selectively Hydrogenated Free radical chain reaction initiated in furnace tubes

Halliburton Kellogg Brown &

Root (milli second) Lummus Stone & Webster CF Braun Linde BASF ExxonMobil KTI Technip

Each furnace designer has their own characteristics

Temperature ranges 700°C to 900 °C

Residence times 0.2 ( new units) to 15 secs (older design)

Steam injection into the furnaces minimise coke gives CO formation (C + H2O=CO+ H2) 0.2 to 0.5 wt% feed

Tube outlet pressure 0.5 to 2 bar

T 1 0 2

Feed

Gasoline

Fuel Oil

Caustic wash

Cold Box

H2, CH4

Demethaniser

H2 De-ethaniser Tail End

acetylene

Mixed C4 to splitters

Gasoline Secondary Demethaniser

Ethylene Product

Ethane Recycle

800°C

400°C

-100°C

-50°C

-33°C

60°C

-17°C

120°C

0°C

H2

MAPD Converter

C3 to splitter

Depropaniser Debutaniser

Drier

C2H6 C3H8

Recycle Furnace

Furnace

FRONT END DE_ETHANISER C2H2 Reactors

Driers

T 1 0 2

Cold Box

C3’s, C4’s and pygas C2H4/C2H6

CH4, CO H2

Demethaniser

De-ethaniser

FRONT END DE_DEPROPANISER

Driers

T 1 0 2

C4’s and pygas Depropaniser

C2H2 Reactors

Cold Box

C2H4/C2H6 CH4, CO H2

De-ethaniser

Demethaniser C3H6/C3H8

Gas Compression System

Gas Compression System

Wet Front EndDe-propaniser

Front EndDe-ethaniser

Tail EndDe-ethaniser

H2 32.00 20.00 19.00 -CO 0.07 0.06 0.09 -CH4 9.00 26.00 35.00 1.00C2H2 0.30 0.50 0.90 1.50C2H4 34.00 30.00 38.00 75.00C2H6 22.00 6.30 7.00 22.50C3H4 0.03 0.80 - -C3H6 1.00 9.00 - -C3H8 0.30 8.00 - -C4H6 0.60 0.02 - -C4H8 0.07 - - -C4H10 0.03 - - -

C5+ 0.25 - - -H2O 0.40 - - -

SV (h-1) 5-8000 5-8000 5-8000 1.5-3000P (bara) 15-35 15-35 15-35 15-35T (°C) 70-90 70-90 70-90 40-120

Front end acetylene -( Pd on alumina) De-ethanizer overhead Depropanizer overhead Wet gas

Tail end acetylene -(Pd on alumina) MAPD and butadiene -(Pd on alumina) Methanation catalysts ( Ni on alumina) High activity hydrogenation for C4 or C5 recycle (Pd or HTC) Pyrolysis gasoline -( Ni or Pd on alumina) Ethylene / propylene purification systems Purification

Hg from feed or upstream of Pd catalysts Arsenic from feed or C3 cut or from py gas feed COS hydrolysis in the wet gas system H2S ZnO absorption

SG15/4 or 15/15 equivalent to kg/m3 T in SOR inlet temperature start of run T in EOR inlet temperature end of run Partial pressure NOT same as reactor

pressure Hydrogen terminology

◦ Chemical usage nm3/m3 feed ◦ Solution loss nm3/m3 ◦ MUG-make up gas nm3/hr ◦ Purge gas excess hydrogen to remove

inert gases ◦ Recycle gas rate

LHSV volumes feed/volume catalyst Reactor fill cost gives actual cost for

comparisons ( Catalyst SG)

Life Hours m3 feed/kg catalyst preferred or feed component converted

GHSV care is it actual or normal basis? EIT equivalent isothermal temperature

(WABT) Feed distillations (Check out what they

are) ◦ ASTM ◦ TBP ◦ Sim Dist GLC ◦ Boiling range

Average boiling point Others (Check out what they mean) ◦ MAV ◦ UV ( not only at one wavelength) ◦ Iodine number ◦ Bromine number

Base Intermediate FinalC2H2 + H2 = C2H4 + H2 = C2H6

C2H2 = CH2 CH CH CH2Butadiene

= Green oil

CH3 C CH + H2Methyl Acetylene

= CH3 CH CH2propylene

CH2 C CH2 + H2Propadiene

= CH3 CH CH2propylene

CH2 CH CH CH2 + H2Butadiene

= CH3 CH CH2Butylene

CH2 CH CH CH2Butadiene

= Green oil

Relative reactivitiesC2H2 > C4H6 > C3H4 (MA) >> C3H4 (PD) > C2H4

ConversionC2H2 - Acetylene 100% C3H4 - Methyl Acetylene 90%C3H4 - Propadiene 20% C4H6 - Butadiene 90%

Ethylene Selectivity :

% SC2H4 = 100 - % SC2H6 - % SC4+ - % SC6+

% SC2H6 is the ethane selectivity :

% SC2H6 = {[(C2H6)out –(C2H6)in]/[(C2H2)in-(C2H2)out ]}x 100

% SC4+ is the total C4 selectivity formed (i.e. Cis- andtrans-but-2-enes, but-1-ene and buta-1,3-diene), :

% SC4+ = {[2x(C4'sformed)]/[(C2H2)in-(C2H2)out]} x 100 (2 moles C2H2 1 mole C4’s)

% SC6+ is the total C6 selectivity formed,:

% SC6+ = {[3x(C6'sformed)]/ [(C2H2)in-(C2H2)out]} x 100 (3 moles C2H2 1 mole C6’s)

Important to ask customer his definition, many variations

Catalysts are sock loaded Can be regenerated some in situ

steam/air some offsite No activation step used No of reactors and configuration

depends on plant New units, 25°C −T each reactor Front end units always work in

high CO and excess hydrogen Tail end 2 to 5% excess hydrogen

5 ppm added CO. Susceptible to green oil formation.

Usually one spare in either front or tail end systems. Will vary

Acetylene spec is >10ppm in C2H4. This is <1ppm front end design

Cooling Medium C4 Methanol

Cracked Gas Cracked Gas

FRONT END

Isothermal Adiabatic

TAIL END

Components Average HighC3’s 0.3 0.3N-butane 5.2 2.8Iso-butane 1.3 0.61-butene 16 13.7Cis 2-butene 5.3 4.8Trans 2 –butene 6.6 5.8Iso butene 27.4 22.2Butadiene 37 47.5Acetylenics 0.4 1.8C5’s 0.5 0.5

The LPG stream often further processed. Butadiene can be extracted, selective hydrogenation of raffinates, mono olefins into co polymers, solvents etc, MTBE . Full hydrogenation of C4’s for LPG transportation fuel or recycle to the furnaces.

Feed Tower Optional

C10+ Optional

C5 Optional

C5 Optional

Fuel gas

Rerun Tower Optional

Stabiliser

BTX extraction or Motor Gasoline

1st STAGE 2nd STAGE

C5 Tower Optional

Composition wt%C5-200 °C C6-200 °C C6-C8 Cut

Parrafin / Naphthenes 11.8 7.8 9.7Olefins 5.5 2.4 3.0Diolefins 18.1 8.7 5.9Aromatics

Benzene 28.0 35.2 43.7Toluene 13.9 17.4 21.7

C8 7.2 9.0 11.3Alkenylbenzene

(styrene)3.0 3.8 4.7

C9+ 12.5 15.7 -

Total Aromatics 64.6 81.1 81.4

Sulphur ppm wt 220 180 150

CrudeGasoline

Hydrogenated Hydro-treated

IP (ASTM) °C 40 43 4350% °C 98 100 100EP °C 195 200 200SG 0.83 .832 .835Diene I2gms/100gms 27 1 >0.1Bromine No 75 60 >0.5Total Sulphur ppm 400 400 >1Styrene wt% 5.0 0.1 >0.001RONC 97 97MONC 86 86

Catalyst HTC /Pd NiMo/ CoMo

Temperature In/Out °C 70/120 250/320

Pressure Bar 27-50 27-50LHSV 1 to 3 1 to 3

Some Definitions -2

Purge gas Inlet Temperature

Partial Pressure Hydrogen consumption

Make up gas

Recycle gas

Solution loss in product

Outlet Temperature

EIT =Tin+ (Tout-Tin) x (2/3)

Fresh Feed

Distillation curves

0

50

100

150

200

250

0 20 40 60 80 100

Volume % distilled

Tem

pera

ture

Deg

C

TBP/Sim Dist

ASTM D86

Important to define ASTM { D86 (<350°C EP) or D1160 (> 350°C IP)}, Sim Distillation (HPLC/GLC)

Distillation Data and SG is minimum required to calculate other properties ◦ Average boiling points (TABP,

MeABP, VABP) ◦ K for flash data ◦ MW or hydrogen consumptions

◦ Critical properties (Tc Pc) and heats

of reaction ◦ n-d-m data for aromatic contents

Gives properties of the feeds and products for calculations.

Pilot plant isothermal Plant adiabatic Use Tin conversion too

low Use T out conversion too

high EIT = Tin +(Tout-Tin) x Ι Choose some point to try

to match conversion ◦ will depend on reaction ◦ slow Ι = 0.4 ◦ fast Ι = 0.75 ◦ average Ι = 0.66

Look out for equilibrium operations

Flow FL

Flow RL

Flow RG Flow MG

Conversion Data

455565758595

75 125 175

Temperature Deg C

Conv

ersi

on w

t%