acetic acid
DESCRIPTION
Acetic Acid. By Hamad Shaabi Reyan Rutherford Shaun Lynn Andrew Pollock. Marketing. Marketing. Method. Ethylene via acetaldehyde Methanol by carbonylation Butane by liquid-phase oxidation Cativa Process. Ethylene via acetaldehyde. CO2 Removal. OFF Gas. Steam. - PowerPoint PPT PresentationTRANSCRIPT
Marketing
Asia60%
North America22%
South America
2%
Europe11%
Middle East2%
Rest of the World3%
Acetic Acid Demand Major Region
Asia57%
North America
4%
South America
2%
Europe14%
Middle East23%
Acetic Acid Supply Major Region
Region Demand Supply Import Export
Asia 37 57 - 20
North America 22 4 18 -
South America 2 2 - -
Europe 11 14 - 3
Middles East 2 23 - 20
Marketing
Vinyl Ac-etate
Monomer37%
Terephthalic Acid17%
Acetate Es-ters11%
Acetic Anhy-dride8%
Others27%
Global Acetic Acid Derivatives
Acetic acid Derivatives Uses
Vinyl Acetate Monomer Paints, adhesives, coating, textiles, wire and cable polyethylene compounds
Terephthalic Acid Bottles, textiles, polyester fibers
Acetate EstersPaints, coating, inks formulation, sealants, adhesives in pharmaceutical applications
Acetic Anhydride Cellulose acetate fibers, plastics, pharmaceutical such as aspirin
Others Chemical reagent
Method
Ethylene via acetaldehydeMethanol by carbonylationButane by liquid-phase oxidationCativa Process
Reactor 106 °C 10 ATM
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Ace
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Ace
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CO2 Removal OFF Gas
BFW
Steam
EthyleneOxygenNitrogenwater
H2O
stm stm
Acetaldehyde Acetic Acid Product
[PdCl4]²ˉ C2H4 + H2O + ½O2 CH3CHO + H2O CuCl2 CH3CHO + H2O CH3COOH + H2
Estimating plant capital costs
Major Process Step Special Requirements Score
Reaction 10 atm (0.3), Temp 160 °C(0.3),H.G Stainless steel (0.6)
2.2
Scrubber High grade s.s. (0.6) 1.6
CO2 Removal High grade s.s. (0.6) 1.6
Acetic Column High grade s.s. (0.6) 1.6
Acetaldehyde Column
High grade s.s. (0.6) 1.6
Acetic Finishing High grade s.s. (0.6) , entrainment (0.3)
1.9
Total process complexity factor 10.5
Methanol Carbonylation
Most used process for production of Acetic acid.
Developed by Henry Dreyfus at British Celanese, pilot plant opened in 1925.
Uses a metal catalyst, usually Rhodium.CH3OH + CO CH3COOH
Methanol Carbonylation
1. CH3OH + HI CH3I + H2O
2. CH3I + CO + [Metal Catalyst] CH3COI
3. CH3COI + H2O CH3COOH + HI
CH3OHHI
CH3I
H2OCO + [Metal Catalyst]
CH3COI CH3COOHH2OHI
Reaction carried out at a minimum of 200atm.
Methanol Carbonylation
• Methanol and carbon monoxide are the raw materials.
• Bi-products are separated using distillation.
Methanol Carbonylation Complexity Factor
Major Process Step Special Requirements Score
Reaction200 atm (0.9)
Temp 200 °C(0.3)High Grade Stainless steel (0.6)
2.8
Scrubber High Grade Stainless steel (0.6) 1.6
CO2 Removal High Grade Stainless steel (0.6) 1.6
Acetic Column High Grade Stainless steel (0.6) 1.6
Acetaldehyde Column High Grade Stainless steel (0.6) 1.6
Acetic Finishing Entrainment (0.3)High Grade Stainless steel (0.6) 1.9
Total process complexity factor 11.1
Cativa
• Developed in 1996 by BP.
• Uses Iridium catalyst.
• Requires Catalytic Promoter – Ruthenium
• Increase in“active anionic” species Ir(CO2)I3Me]-
Cativa Process
• First step is no longer the rate determining step
• Cativa Process 150x faster than Monosanto
• Rate = [catalyst] x [CO]
[I-]
• Very high yield 95-98% at 99% purity
Advantages of the Cativa process• Iridium is much cheaper than rhodium • Less iridium is needed because it is so stable that all the
catalyst is recycled in the plant • The reaction is faster and the quantities of by-products are
much lower, reducing the purification costs. For example steam is used to heat the distillation columns and there is a 30% saving of steam over the Monsanto process
• Some conversion of CO to CO2 still occurs but at a much lower rate
• CO utilisation is increased from about 85% to over 94% • Overall the Cativa process releases about 30% less CO2 per
tonne of product than does the rhodium process
Acetic Acid by Butane Oxidation• When butane is heated with air in the presence of a metal catalysts acetic acid is produced.
C4H10 + 2½ O2 → 2 CH3COOH + H2O
• Suitanle metal catalysts are manganese, cobalt and chromium.
• Conditions are run at a combination of temperature and pressure designed to be as hot as possible while keeping the butane in a liquid phase. Typical conditions are 150°C an 55 atm.
• The reaction produces side products such as ethyl acetate, butanone and formic acid which are commercially valuable.
• Reaction conditions can be altered to produce either of these as the major product if this is economically useful.
• Before methanol carbonylation became commercialised in the 1980s, Butane oxidation was the major source of acetic acid
• Now produces less than 10% of acetic acid supply annually.