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Contact Section - Catalysts
- Monsanto Enviro-Chem Systems
Janury 18, 2003
Introduction
The history of catalyst production at Monsanto dates back to
the 1920's when German scientists A.O. Jaeger and J.A. Bertsch were contracted to prepare
sufficient quantities of a then new vanadium catalyst for plant trials. The trials
were successful and further research and development resulted in the issue of US Patent
No. 1,657,754 on Januray 31, 1928 for the catalyst known at that time as the Monsanto
Mass.
Today, Monsanto offers 8 different types of catalyst for
various applications and situations. The most commonly specified catalysts are the
LP (Low Pressure Drop) ring type catalyst. The cesium-promoted Cs type catalysts
were introduced in 1989 which have higher activity and lower strike temperatures that the
standard catalysts.
Catalyst Types
The physical properties of the catalyst are provided in the
following tables and a brief description of each catalyst is given below.
Pellet Catalyst
| |
Type 210 |
Type 516 |
Type 11 |
| I.D. (mm) |
- |
- |
- |
| O.D. (mm) |
5.5 |
8.0 |
5.5 |
| Length (mm) |
12 |
15 |
12 |
| Attrition Loss (%) Ball Mill Test |
- |
- |
- |
| Crush Hardness (kg) |
12 |
16 |
12 |
Type 210
This is an all purpose catalyst that provides
a balance of high activity formulation and geometry. Type 210 is used in low
velocity converters to aid in the distribution of gas across the bed. This catalyst
exhibits high mechanical strength which minimizes losses during screening.
Type 516
This catalyst is designed for use where a low pressure drop
catalyst is required in the first pass but the gas velocity is too low for LP-120.
Type 516 exhibits a 30% lower pressure drop than Type 210. The catalyst is designed
for use in beds 1 and 2 and offers high activity and good mechanical strength
Type 11
The characteristics of Type 11 are generally the same as Type
210 but with higher activity which make the catalyst ideal for the 3rd, 4th and 5th beds
of a converter. The formulation is specific for high SO3
conditions and lower temperatures that are typical of beds 3, 4 and 5. The activity
of Type 11 is approximately 25% higher than Type 210.
Ring Catalyst
| |
LP-120 |
LP-110 |
LP-220 |
LP-1150 |
TD-750 |
| Shape |
Ring |
Ring |
Ring |
Ring |
Ring |
| I.D. (mm) |
5.0 |
4.0 |
|
|
|
| O.D. (mm) |
12.5 |
9.5 |
|
12.7 |
19.0 |
| Length (mm) |
14 |
13 |
|
12.7 - 14 |
|
| Attrition Loss (%) Ball Mill Test |
3.0 |
8.5 |
|
- |
- |
| Crush Hardness (kg) |
- |
- |
|
- |
- |
LP-120
This catalyst was first introduced by Monsanto in the late
1970's and early 1980's and was based on the original T-210 type catalyst. The old
formulation in the new ring shape sufferred from higher than acceptable attrition losses
so a new formulation was developed. This catalyst is primarily used in the first and
second passes of a converter where low pressure drop and high activity are required.
The large ring provides a high void volume permitting greater dust penetration and
more uniform dust distribution. This translates to less pressure buildup over time
and less frequent screenings.
LP-110
LP-110 is formulated to provide high activity and is used in
the lower passes of the converter where low temperatures, high SO3
and low O2 are present. The catalyst is very durable
and losses during screening are low. This catalyst was introduced by Monsanto in
1981.
LP-1150
LP-1150 is a newly formulated catalyst specifically designed
for lower bed installation to provide improved cnversin efficiency. The catalyst is
approximately 10% more active than LP-120 in Bed 2 applications.
TD-750
TD-750 "Top Dressing" catalyst is a large 19 mm
diamter ring catalyst designed to replace the quartz rock in low linear velocity catalyst
beds. The catalyst has the same formulation as LP-120 catalyst but only 50% of the
activity due to the inefficiencies associated with its larger ring size.
Cesium-Promoted Catalyst
| |
Cs-120 |
Cs-110 |
Cs-210 |
SCX-2000 |
| Shape |
Ring |
Ring |
Pellet |
Ring |
| I.D. (mm) |
5.0 |
4.0 |
- |
|
| O.D. (mm) |
12.5 |
9.5 |
5.5 |
9.5 |
| Length (mm) |
14.0 |
13.0 |
12.0 |
9.5 - 13.0 |
| Attrition Loss (%) Ball Mill Test |
3.0 |
8.0 |
- |
|
| Crush Hardness (kg) |
- |
- |
12.0 |
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Cs-120
This cesium-promoted catalyst is designed for upper pass
applications where dust will accumulate in the bed. The large diameter ring allows
for greater dust penetration which results in longer operation before the catalyst must be
screened due to increases in pressure drop.
Cs-110
This cesium-promoted catalyst is designed for lower pass
applications where temperatures are lower and the presence of SO3
inhibits the further conversion of SO2 to SO3.
The catalyst is a smaller ring than Cs-120 which increases the surface area to
volume ratio. This catalyst was introduced by Monsanto in 1989.
Cs-210
Like all pellet shape catalyst the pressure drop is higher
than ring shaped catalyst. This feature make this cesium-promoted catalyst ideal for
the low gas velocity converters.
SCX-2000
SCX-2000 is a newly formulated cesium-promoted catalyst
designed specifically for lower bed applications in single or double absorption plants.
In addition to the new formulation, the catalyst support structure is enhanced.
Ribbed Catalyst
| |
XLP-220 |
XLP-110 |
XCs-110 |
| Shape |
Ribbed |
| I.D. (mm) |
3.8 |
| O.D. (mm) |
11.9 |
| Length (mm) |
9.5 - 14.0 |
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