The document discusses low temperature shift catalysts used in hydrogen production plants. It describes the purpose of low temperature shift catalysts in further converting carbon monoxide to carbon dioxide to improve hydrogen yield and remove impurities. It then covers the chemistry, typical operating conditions, factors influencing catalyst activity like temperature profile and poisons, and byproduct formation issues. The document promotes the VSG-C111/112 series as superior catalysts, highlighting their resistance to poisons like sulfur and chloride, low methanol byproduct formation, high activity, and strength properties.

1. Low Temperature Shift
Catalyst
By:
Gerard B. Hawkins
Managing Director, CEO

2. Conventional Hydrogen Plant

3. Low Temperature Shift
 Purpose
 Chemistry
 Operating Conditions
 Catalyst Activity
 Poisons
 By-Product Formation
 Effects of Water
 Catalyst Requirements
 VSG-C111/1122 - Series

4. LTS - Purpose
 Generate H2 from steam - improve plant
efficiency
 Convert CO to CO2 for easier removal
• CO is converted to CO2 in two stages of
shift conversion
 LTS is the second stage of shift conversion to
generate H2
• Residual CO conversion - critical to
operating economics
• Reduce CO levels to typically 0.3 mol%
(dry)

5. LTS - Chemistry
CO + H2O ⇔ CO2+ H2 ∆H = -41.1 kJ/kgmol
• Reaction catalyzed by Cu for LTS
• CO lowered from typically 3% to 0.3%
• High conversion is favored by
– Low temperatures
– High steam concentration
• Typically accomplished using copper on a
zinc-alumina support
Cu

6. LTS – Typical Operating Conditions
SOR EOR
Temp (°F) 356 - 392 410 - 446
CO (vol%) 3 – 5
Temp (°F) 410 - 518
CO (vol%) 0.2 – 0.3
CO + H2O
CO2 + H2
Inlet
Outlet
Inlet temperature ≥ 27°F above dew point

7. LTS - Temperature Profile
Top
Bed Depth
Bottom
Temperature
Ageing
Movement
• Ageing mechanism is gradual poisoning

8. LTS - Catalyst Activity
 Good, stable catalyst activity
• Maximum conversion of CO to CO2
• High kinetic rate at low LTS inlet
temperatures
 Conversion limited to equilibrium
 Operational measure of activity:
• temperature gradient through catalyst
bed
• higher activity gives steeper gradient

9. LTS - Catalyst Activity
 Activity is NOT directly related to Cu
content or Cu surface area
• Cu content must be highly dispersed and
stabilised
(hence content is not a good measure)
• Cu crystal phases and structure important
to activity (therefore surface area is not a
direct measure)
 Only real test is in laboratory under
faithfully reproduced plant conditions and
on operating plants
• Initial activity may not have any
relationship with long term activity
retention

10. LTS – Catalyst Activity
 ATE (approach to equilibrium) is usually
very close
• CO slip not impacted by activity for
most of catalyst life
• Does not affect movement of
temperature profile through bed
 Minimum inlet temperature restricted by
dew point
• Not always possible to reduce inlet
temperature to optimal value to take
advantage of activity
Not the most important parameter!

11. LTS - Temperature Profile
Top
Bed Depth
Bottom
Temperature
Ageing
Movement
• Ageing mechanism is gradual poisoning
Goal: Slow the rate of temperature profile
movement down the bed

12. LTS – Catalyst Poisons
 Sulfur
• Powerful poison
• Trapped by the catalyst as Cu2S and ZnS
 Chloride
• Severe poison
• Reacts with copper and zinc to form
chlorides
• CuCl formation provides a mechanism for
loss of activity by sintering

13. LTS - Mechanism of Sulfur Poisoning
ZnO
Cu
ZnO
Cu
Zn2+
Cu
ZnO
Cu
Adsorption on Copper Surface Mobility
Surface Sulphide
Formation
Bulk Sulphide
Formation
S
S
ZnS

14. LTS - Chloride Poisoning
 Chloride reacts with copper to form
CuCl (mp = 430oC)
 CuCl formation provides a mechanism
for loss of activity by sintering
 Requires well dispersed and
stabilized copper to minimize the
effect of chloride

15. Chloride Poisoning of LTS Catalysts
Chlorided LTS Non-chlorided LTS
Copper clusters
normal sizeCopper clusters sintered
Lost surface area

16. Chloride Poisoning of LTS Catalysts
Chlorided
LTS
Sintered Copper
ball large surface
area loss

17. Effect of Particle Size on Poisons
Resistance
0
20
40
60
80
100
Cumulative Chloride Level
COconversion(%)
0.3 - 0.6mm
0.6 - 1.0mm
1.18 - 1.4mm
1.4 - 1.7mm
•Poisoning reactions with H2S and HCl are strongly
diffusion limited
•Poisons resistance and activity can be increased
by increasing the pellet geometrical surface area

18. LTS - By Product Formation
• Methanol
– Effect quality of CO2
– Quality of process condensate
• Environmental legislation
• Increased treatment costs
– Odor in CO2 vent
• Can produce amines
• When vented can be a nuisance
– Other oxygenates such as ethanol, ketones

19. LTS - By Product Formation
• Methanol Formation
CO2 + 3H2 <====> CH3OH + H2O
• MeOH increases with
– High Temperatures
– High inlet CO levels - increases LTS temperature rise
– low S:C ratio
– Low space velocity / catalyst bed volume
• MeOH production decreases rapidly in the
first few months of LTS catalyst operation

20. • Condensate
– If catalyst is operated at too low temperature
• Waste Heat Boiler Leaks
– Wetting then evaporation reduces strength
significantly
– Can cause catastrophic failure due to thermal
shock
– Loss of activity due to blocking of active sites
– Pressure drop increase
• catalyst break-up
• boiler solids fouling catalyst
LTS - Effects Of Water

21. LTS - Effects Of Water
• Water will dissolve soluble poisons
– wash poisons deep into the bed
– Increase affected bed depth
– accelerate change-out of the catalyst
Remember
CuCl2 is soluble in water!

22. Key Performance Requirements
 Poisons Resistance
• Self guarding capacity
 Selectivity
• Minimize by-product formation
(methanol)
 Activity
• Minimize CO slip
• With minimal catalyst volume
 Strength
• Withstand upsets such as condensation

23. VSG-C111/112
Superior Poison Resistance
Low Methanol By-product Options
High Activity
High Strength
Extended Catalyst Life
Short Load Potential to fit T/A Cycles
Maximize Hydrogen Production
Address Environmental Concern
Resilient

24. Superior Poison
Resistance

25. Improved Poison Retention using
VSG-C111/112 series
High sulfur retention
Typical = 1% at top &
0.1% at the bottoms
Impact of chloride poisoning
on CO conversion

26. Extra Chloride Poisons resistance
 Applications confirm expected
activity for CO and low methanol.
 Additional benefit is the
enhanced ability to chloride
guard.
• Caesium and potassium have the
highest driving force for chloride.
• This is shown by the fact that CsCl
and KCl will be formed at very low
levels of HCl.

27. Equilibrium HCl Concentration

28. Chloride Guarding Properties of
VSG-C111/112 series
• Very stable chlorides are formed
Chloride Mp (o
C) Bp (o
C)
CuCl 430 1490
ZnCl2 283 732
CsCl 645 1290
KCl 770 1500 subl

29. Mechanism of Chloride
Resistance
ZnO
Cu
Adsorption on Potassium
HCl
CsCl
ZnOCs
Bulk Chloride Formation
K and Cs protect the Cu/ZnO lattice by preferentially
reacting with and trapping chloride poison
Cu

30. Sulfur Poisoning & Surface Area
Competitors
VSG-C111/112

31. 2 4 6 8 10 12 14 16
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Sample Depth (ft)
Poison Level (%)
Cl (%)
S (%)
Poison Profile for VSG-C111, Chinese Hydrogen Plant
Sulfur & Chloride Retention of
VSG-C111/112
= 13,000ppm!

32. Relative Impact of Activity
and Poison
Base (VSG-C111)
+20%act
+20%poison

33. Low By-product Formation
(Methanol)

34. Plant Performance
 Optimized alkali promoters to achieve
high activity for shift conversion while
reducing methanol synthesis
--------VSG-C111 ---------VSG-C112 Plant Data

35. Laboratory Testing
Product Methanol Activity
VSG-C112 0.18
Comp A low MeOH 0.26
Comp B low MeOH 0.33

36. High Activity

37. Activity Comparison (Laboratory)
Minimize CO slip
0.20
0.22
0.24
0.26
0.28
0.30
0.32
0.34
0 2 4 6 8 10
Time on-line (years)
COslip
Com petitor A
KATALCO 83-3X
Com petitor C
---------- Competitor A
---------- VSG-C112
---------- Competitor C

38. Case Study: Longer Life
(1700 stpd China Ammonia Plant)
 Previous competitive charge achieved only 3-yr
life before high CO slip (> 0.3 mol%) when 4-yr
was expected
 Replaced with VSG-C112 and operating 5+ yrs
with less than 0.25 mol%
$$$ Saved ~ $170,000
+
Avoided Unscheduled S/D
+
12-month Extension on T/A

39. High Strength

40. Relative Strengths of Fresh and
Reduced Catalyst
 VSG-C112 series formulated to
have high strength after reduction
VSG-C112 Competitor A Competitor B

41. Horizontal Crush Strength after
Reduction and Condensing Steam
Conditions
 Compares relative strength of VSG-C112
and competitive low methanol products
VSG-C112

42. Conclusions
 VSG-C112 excels over all products
with
• More than adequate activity
• Poisons resistance at least equal to a
‘famous and soon to be obsolete’ guard
material with claimed ‘unrivalled poisons
resistance’
• The lowest by-product Methanol in the
industry
 So for long life, low CO slip, Low
Methanol VSG-C112 is the winner

43. Catalyst Characteristics
 VSG-C111
Copper oxide/Zinc Oxide/Alumina
 VSG-C112
As above, promoted by alkali metals

44. Lab Based Test Program
 Ability of the Topsoe LSK Guard to
withstand chloride poisoning relative to
VSG-C112
 Determined in the laboratory using an
accelerated poisoning test.
 In the test a guard layer of the catalyst
sample is placed above a main bed of
VSG-C111 catalyst and the CO conversion
is measured using LTS gas containing
very low levels (50 ppb in this case) of
HCl.

45. Chloride resistance test rig
LTS Feed gas
(60% H2, 21% N2, 16% CO2, 3% CO)
with
50 ppb Chloride poison addition
Analysis of CO
conversion
Standard bed
Test bed
LSK
Analysis of CO
conversion
Standard bed
VSG-C111
Test bed
VSG-C112
VSG-C111

46. Chloride poison test results
% Conv vs Wt Cl addition (gms)
Run No PR133 - 50 ppb HCl addition
0
10
20
30
40
50
60
70
80
90
100
0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0.0045
Wt Cl addition (gms)
%Conversion
PR133B - U4676 Topsoe LSK PR133C - H1106K Std 83-3XVSG-C111

47. Chloride poison test results
TOPSOE LK-823 and LK-821-2
1ppm HCl addition
Charged as guard beds (0.2mls) above main beds Std 83-3 (0.4mls)
Main Bed SV ~ 127000
0
20
40
60
80
100
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Wt Cl addition (gm)
%conversion
PR59 - 83-3X PR59 - LK-823 PR59 - LK-821-2 PR59 - 83-3KVSG-C111

48. Overall comparisons
Activity/selectivity on volume comparison
Catalyst Relative
Activity(v/v)
Relative
Methanol
Make(v/v)
LSK 0.52 0.44
LK 821-2 1.20 0.88
VSG-C111 1.18 0.20

49. Competitive Summary

50. Laboratory Poisoning Data
Analysis of CO
conversion
Standard bed
Test bed
Cat B
Analysis of CO
conversion
Standard bed
Test bed
Cat C
LTS Feed gas
(60% H2, 21%N2, 16% CO2, 3% CO)
with
Chloride poison addition
Analysis of CO
conversion
Standard bed
VSG-C111
Test bed
Cat A
Analysis of CO
conversion
Standard bed
Test bed
Cat D
VSG-C111 VSG-C111 VSG-C111

51. How do We Compare?
Product Relative Poisons
Absorption *
VSG-C111 1.0
VSG-C112 2.13
Comp A Guard ** 2.1
Comp A std 1.0
Comp A low MeOH 1.28
Comp B std ?
Comp B low MeOH 0.70
* Chloride pickup relative to VSG-C!!! measured by CO slip vs time and chloride
analysis on spent material
** Guard with almost no sulfur capacity and very low activity