SECTION I(b)
(8) I.G. Farben-Ludwigshafen.
Waelzgas Process. (See reference I(b)/8, I(b)/9, and I(b)/10 at end of this section).
The gas circulating process (Dr. Michael) was well known before 1938 and had been discussed with U.S. representatives at the time. Dr. Michael used his sintered catalyst prepared by treating pelleted Fe powder (from carbonyl) with K2CO3 solution and sintering in H2 atmosphere at 800-850° C for 4 hrs. The catalyst was actually iron carbide. But no exact work on the different carbides appears to have been carried on. The catalyst was not active requiring a temperature of 325° C for a 75% conversion.
When it became apparent that the process could not compete with high pressure hydrogenation in the production of high octane gasoline, it was decided to develop a process for the production of chemicals particularly olefins. The sintered catalyst was abandoned and replaced with a precipitated Fe catalyst. This catalyst did not have the mechanical strength required in the “Waelzgasprocess” and the process was abandoned. All further work carried out by Dr. Michael centered around operation in liquid phase and is described in that section.
For ready reference a set of operating data is listed below:
|
Reactor: |
4 m3 sintered Fe catalyst |
|
Temperature |
325° C |
|
Pressure |
20 atm. |
|
V/H/V |
250 |
|
Feedgas |
CO: H2 = 4:5 (17% inert) |
|
Catalyst yield |
0.7 Kg/liter catalyst/day |
|
Product Distribution: |
||
|
C2H4 |
8% |
|
|
C3H6 |
9% |
|
|
C3H8 |
3% |
|
|
C4H8 |
8% |
|
|
C4H10 |
2% |
|
|
Gasoline 200° C |
48% |
|
|
Diesel oil 200-350° C |
14% |
|
|
Wax |
1% |
|
|
Alcohols |
7% |
|
|
Total |
100% |
|
22 pts. Of methane-ethane are also formed for 100 pts. Of the listed products.
The gasoline must be refined (dehydration of alcohol) to remove oxygen. This causes about 6% loss. The treatment is carried out at 380° C over alumina. The treated gasoline has a Res. O.N. of 84. The diesel oil is ready for use, cetane number 50-55.
A horizontal reactor has been proposed to carry out the synthesis containing 20 m3 of catalyst arranged in 4 separate horizontal layers of 250 mm. Thick. Two reactors of this type would yield 10,000 ton/year of FT product. Note that this daily production per unit catalyst volume is about three times that reported in commercial Ft operation. This is due to the higher space velocity, but the data should be used with caution.
A fairly detailed cost estimate for a 100,000 ton/year plant had also been worked out. The detailed figures may be taken from the attached report by Dr. Michael. The cost figures given are very nearly the same as these listed by Lurgi for a conventional Ft plant using Fe catalyst and gas “Kreislauf:.
| Basis: |
Rm/1 yearly ton total product |
Synthesis & Recovery |
Total Plant |
|
I.”G. (Waelzgas unit) |
243.- |
865.- |
|
|
Lurgi (Kreislauf) |
290.- |
590.- |