SECTION I(b)
11. “Schaumfahrweise” Process-I.G. Farben.
(a) Catalyst.
The catalyst was prepared by decomposing iron carbonyl, 1% alkali was added. After reduction the catalyst was ground in oil to 1-5 m particle size. The concentration in the liquid was 300-400 Kg/m3.
The catalyst operates at comparatively low temperatures and the amount of gas formed is small. At 70% conversion, the gas analyses are as follows:
|
Feed gas |
Tail gas |
|
|
CO2 |
0.8% |
30.4% |
|
CmH2n |
- |
3.0% |
|
H2 |
42.5% |
31.1% |
|
CO |
53.6% |
27.8% |
|
HCs |
1.0% |
3.7% |
|
N2 |
2.1% |
4.0% |
It is therefore possible to remove the CO2, and return the tailgas to the reactor without at the same time diluting the feedgas with inert components, thereby the ultimate conversion could be increased to 90%.
The capacity based on reactor volume varied with temperature. For operation at 20 atm. the following figures were given:
|
Temperature |
Space Velocity |
|
250° |
80 m3 gas/m3 reactor |
|
275° |
125 m3 gas/m3 reactor |
Note: That the space velocity is again in the same range as in ordinary FT operations. For 100,000 ton year primary product, 950 m3 reactor volume are required according to Dr. Michael corresponding to 2.9 ton/day/10m3 catalyst.
PRODUCT DISTRIBUTION
|
Boiling Range |
% Weight |
% Paraffin |
% Olefine |
% Alcohol |
% Acid & Ester |
|
1-50° C |
4 |
12 |
85 |
0 |
3 |
|
50-100° |
20 |
7 |
83 |
5 |
5 |
|
100-150° |
16 |
11 |
67 |
15 |
7 |
|
150-200° |
10 |
20 |
62 |
12 |
6 |
|
200-250° |
12 |
17 |
63 |
12 |
8 |
|
250-300° |
10 |
25 |
54 |
10 |
11 |
|
300-350° |
8 |
38 |
45 |
5 |
12 |
|
+350° |
20 |
- | - | - | - |
Note the content of olefins and oxygenated compounds.
For commercial practice a 12-15 m3 oven was considered practical. No plant costs had been calculated for this type of unit but for a 100,000 T/year plant the following utilities were required. (This includes complete plant and product recovery).
|
Steam |
12.5 ton/hr. |
|
Water |
3500 m3/hr. |
|
Power |
3120 KW |
|
Fuel |
2x106 K cal/hr. |
|
Labor |
71 men/shift |