Selection of carbon catalysts for the industrial manufacture

16 Pages·2013·0.36 MB·English

Selection of carbon catalysts for the
industrial manufacture of phosgene
Chris Mitchell
Huntsman Polyurethanes
Acknowledgements
• The teams in the Huntsman laboratories in the Netherlands and Belgium
Willem van der Borden
Klaas van der Velde
Mark Smit
Remy Scheringa
Khalid Ahrika
• Don Jones for the preparation of the Aspen Custom Model
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Introduction
• Phosgene used industrially in the manufacture of polyurethanes,
polycarbonates, pharmaceuticals and agrochemicals.
• Gas phase reaction of chlorine with an excess of carbon monoxide
over an activated carbon catalyst
• Highly exothermic process with peak temperatures reaching over 500oC
• Issue with catalyst lives in different plants
• Focus on the evaluation of commercially available catalysts
- Chemviron
- Donau Carbon
- DuPont
- Norit
- Pica
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Reaction Thermodynamics
1 1
H 109.55kJmol1 S 136.94JmolK
     
1
0.8
n
o
si
er 0.6
v
n
o
c
m
u
ri
b 0.4
uili
q 1 bar.a
E
2 bar.a
4 bar.a
0.2
6 bar.a
0
0 200 400 600 800
Temperature (°C)
• Thermodynamics limits conversion at high temperatures
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Lab Scale Catalyst Testing
PI
NRV-x= Non Return Valve Purge line
N
MFC-x= Mass Flow Controller 2
Oxygen & moisture
V-x = (Three-way) valve 2.5 bar
trap
TR = Temperature recording NRV-1
PR = Pressure recording
PI = Pressure indicator PR
To == CNhitrloorgineen ((CN2l)) V-3 Filter V-1 Pluinrege
2
fume hood = Carbon monoxide (CO)
= Mixture Cl/CO MFC-1
2 reduce
== PPhhoossggeennee//CCOO/N Cl2 valve TR
== NScarOuHbb/He2rO fu (m10e% e2wxh/wau)st 9 bar
5.
g/
k
5
0.4 reduce MFC-2
CO valve
ar
b
0 Oven
5
1
L/
FTIR 0
Gas cell 1
Scrubber TR
TR
V-2
NRV-2 MFC-3
Mixing
PI
chamber
TR
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Lab Scale Catalyst Testing
Temperature Ramp Experiments
350 3.5
300 3.0
250 2.5
)
T inlet v
C) v/
° T outlet %
ure ( 200 CO 2.0 on (
at COCl2 ati
per 150 1.5 ntr
m e
c
e n
T o
C
100 1.0
50 0.5
0 0.0
09:36 09:48 10:00 10:12 10:24 10:37 10:49 11:01 11:13 11:26 11:38
Time
• Reaction “lights off”’ as temperature increases
• Comparison of catalysts at low temperature/conversion
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Lab Scale Catalyst Testing
Measurement of Catalyst Activity
1111111.......6666666
1111111.......4444444 CCCCCCChhhhhhheeeeeeemmmmmmmvvvvvvviiiiiirrrrrriooooooronnnnnnn SSSSSS Sooooooollllllcccccclcaaaaaaarrrrrrbbbbbbrb 222222 200000008888888CCCCCCC DDDDDD DMMMMMMM
1111111))))))) CCCCCChhhhhheeeeeemmmmmmvvvvvviiiiiirrrrrroooooonnnnnn SSSSSSoooooollllllccccccaaaaaarrrrrrbbbbbb 222222000000888888CCCCCC DDDDDDRRRRRR------PPPPPP
-------ggggggg
1111111 DDDDDooooonnnnnaaaaauuuuu SSSSSuuuuupppppeeeeerrrrrsssssooooorrrrrbbbbbooooonnnnn KKKKK4444400000
-------nnnnnnn 1111111.......2222222
mimimimimimimi DDDDuuuuppppoooonnnntttt IIIIPPPPCCCC
ol ol ol ol ol ol ol NNNooorrriiittt RRRBBB444CCC
mmmmmmm
1111111
mmmmmmm NNoorriitt RRXX33eexxttrraa
(((((((
e e e e e e e Picatal G201
atatatatatatat
n rn rn rn rn rn rn r 0000000.......8888888
ooooooo
atiatiatiatiatiatiati
mmmmmmm
rrrrrrr 0000000.......6666666 E = 47 kJmol-1
ooooooo a
e fe fe fe fe fe fe f
nnnnnnn
eeeeeee
ggggggg 0000000.......4444444
sssssss
ooooooo
hhhhhhh
PPPPPPP
0000000.......2222222
0000000
22222225555555 33333330000000 33333335555555 44444440000000 44444445555555 55555550000000 55555555555555
RRRRRRReeeeeeeaaaaaaaccccccctttttttooooooorrrrrrr TTTTTTTeeeeeeemmmmmmmpppppppeeeeeeerrrrrrraaaaaaatttttttuuuuuuurrrrrrreeeeeee (((((((°°°°°°°CCCCCCC)))))))
• Wide spread of catalyst activity is observed
• Synthetic carbon DuPont IPC shows significantly lower activity
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Lab Scale Catalyst Testing
Measurement of Catalyst Effectiveness Factor
1.6
1.4 Donau Supersorbon K40 - crushed
)
1
-g Donau Supersorbon K40 - pellets
1
• Effectiven-nes1s.2 factor () measured using string of
mi
full size col atalyst particles
m
1
m
(
e
at
• Approximon rate0.s8 to a series of CSTRs at low conversion
ati
m
0.6
r
o
e f
n
e
• Direct comsg p0a.4rison of same mass of full size particles
o
h
P
and crushed0 .2catalyst
0
25 30 35 40 45 50 55
Reactor Temperature (°C)
• Effective diffusivities within catalyst pores calculated
from measured effectiveness factors
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Characterisation of plant catalyst
Mercury porosimetry
• Increase in pores between 10 and 100nm in diameter
• Burn out of pores by oxidation
- CTC or CO formation (trace O levels typically 50-500ppm in Cl )
2 2 2
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Catalyst Oxidative Stability
Temperature Programmed Oxidation with 2500ppm O
2
1.E-08
OO
22
HHee
1.E-09 575°C 100ml/min He
(torr) 44 wwaayy 550°C 0.25 ml/min O
4 EEXXTTRRAACCTTIIOONN vvaallvvee 2
4
=
z
m/
e 1.E-10 500°C 0.1g catalyst
s
n
po FFUURRNNAACCEE (250-300m)
s
e
S r 450°C
M
1.E-11 400°C
00..55%%vv//vv CCOO 00..55%%vv//vvCCOO
22 350°C
CCaalliibbrraattiioonn ggaass CCaalliibbrraattiioonn ggaass
1.E-12
0 5 10 15 2EE0XXTTRRAACCTTIIOONN
Time (hrs)
MMAASSSS SSPPEECCTTRROOMMEETTEERR
• Temperature ramped to 575oC and held for 3 hours
• Temperature stepped down at 3 hour intervals – 550, 500, 450, 400, 350oC
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