Steam Reforming Technology User Conference 5-7 March 2007 Bo Hartvigsen, Sales Manager, Haldor Topsoe A/S Challenges in Steam Reforming Challenges in Steam Reforming
Steam Reforming Technology User Conference
5-7 March 2007
Bo Hartvigsen, Sales Manager, Haldor Topsoe
A/S
Challenges in Steam ReformingChallenges in Steam Reforming
Challenges in Steam ReformingChallenges in Steam Reforming
Agenda:
1. Carbon formation
2. Poisoning of catalyst (sulphur)
3. Sintering of catalyst
4. Loading
Carbon FormationCarbon Formation
C2H6 2 CO + 5 H2
2 C + 3 H2
Carbon
+H2O
Reforming
CARBON FORMATIONCARBON FORMATION
• Catalytic cracking
(on Ni crystals)• Thermal cracking
(on hot surfaces)
Two types of carbon formation:
Carbon whiskers, physical
damage of catalyst
Hot bands, NO physical
damage of catalyst
PyrolyticPyrolytic carbon (thermal cracking)carbon (thermal cracking)
Catalyst deactivation and Catalyst deactivation and
carbon formationcarbon formation
0
2
4
6
8
10
12
14
0
Ste
am
to h
igher
hydro
carb
on radio
1 2 3 4 5m from inlet
Critical
Carbon formation from higher hydrocarbons
Actual (high activity) Actual (low activity)
Carbon formation
Formation of hot bandsFormation of hot bands
CnHm CnHm
High
activity
Low
activity
CnH
m
CnH
m
CnHmCnHm
Cn H
m
Cn H
mCn H
m
CnHmCn H
m
850°C
500°C
Hot Bands in top fired reformerHot Bands in top fired reformer
Hot spots in a sideHot spots in a side--fired reformerfired reformer
Reformer design Reformer design
Radiant Wall
Topsøe
Selas
Terrace Wall
Foster Wheeler
Top Fired
MW Kellogg
KTI
UHDE
Bottom Fired
Chemico
Girdler
Risk for carbon formation is higher in a top fired reformerRisk for carbon formation is higher in a top fired reformer
HowHow to to PreventPrevent CarbonCarbon FormationFormation
1. High activity: reform higher hydrocarbons
at low temperatures
2. Use less acidic carrier
3. Promote with alkali
4. (Prereforming)
0
400 500 600 700
Catalyst Temperature
Relative Activity
Impact of Alkali Impact of Alkali
Alkali lower catalyst activity, especially at low temperatures
SulphurSulphur PoisoningPoisoning
Sulphur blocks the Nickel surface area
Nisurface + H2S ↔ S-Nisurface + H2
Temperature dependenceTemperature dependence
0.4
0.6
0.8
1
500 550 600 650 700 750 800 850 900
Temperature, °C
ppbv=10
ppbv=50
ppbv=100
Sulphur Coverage
Dynamics of poisoningDynamics of poisoning
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 20 40 60 80 100
Tube Length, %
Year 1
Year 2
Year 3
Equilibrium
Sulphur Coverage
DesorptionDesorption of of sulphursulphur
0.0
0.2
0.4
0.6
0.8
1.0
1 10 100 1000 10000
Time, hr
Sulphur Coverage
700 °°°°C 800 °°°°C
S-Nisurface + H2 ↔ Nisurface + H2S
SulphurSulphur RegenerationRegeneration
Steam SV : 4000 and T(exit): 800
900
920
940
960
980
1000
0 2 4 6 8 10Time
0
100
200
300
400
PPM SO2
TWT's
BeforeAfter
Temperat ure °° °°C
SO2
S-Nisurface + H2O → NiO + H2S
H2S + 2 H2O → SO2 + 2 H2
Regeneration for CarbonRegeneration for Carbon
Steam SV : 4000 and T(exit): 800
0
2
4
6
8 9 10 11 12
Time
%
O2
CO2
C + O2 → CO2
SinteringSintering
• Decreased C tolerance
• Decreased S tolerance
• Decreased activity
Fresh
Fresh Used
Sintering of Nickel SurfaceSintering of Nickel Surface(Ceramic Reforming Catalyst)(Ceramic Reforming Catalyst)
1
0
0.2
0.4
0.6
0.8
1.0
10 100 1000
Time/hours
RelativeNiarea
aftersinter ings/s0
550°C
700°C
800°C
Triple DeckerTriple Decker
700
750
800
850
900
0 2 4 6 8 10
Distance from Inlet, m
Temperature
TWT
Catalyst
Sulphur Carbon Sintering
RK-211 RK-201 R-67-7H
Properties of Topsoe Reforming CatalystProperties of Topsoe Reforming Catalyst
R-67-7H : Carrier: MgAl2O4 (spinel)
Ni content: 14 %
RK-201: Carrier: CaAl2O4 + MgAl2O4
Ni content: 12 %
K content: 0.4 %
RK211: As RK-201 except :
Doped with noble metal
Prereduced
Reformer loading techniquesReformer loading techniques
• Sock loading
• Unidense™
• SpiraLoad™
SpiraLoadSpiraLoad loadingloading tubetube
The The SpiraLoadSpiraLoad™™ techniquetechnique
Comparison of reformer loading Comparison of reformer loading
techniquestechniques
Time pr. tube, min
Tubes unloaded, %
Manpower
Automised
Sock loading
30-40
~ 2
Demanding
Low
Unidense™
15-20
~ 2
Normal
Low
SpiraLoad™
15-20
0.01
Normal
High
END END
CHALLENGES IN STEAM REFORMINGCHALLENGES IN STEAM REFORMING
QUESTIONS?