(281b) Effect of Ammonia In Syngas On the Fischer–Tropsch Behavior of a Precipitated Iron Catalyst

Kang, J. - Presenter, University of Kentucky

of ammonia in syngas on the Fischer¨CTropsch behavior of a precipitated iron catalyst

Ma, Gary Jacobs, Jungshik Kang, Dennis Sparks, and Burtron H. Davis*

Center for Applied Energy Research, University of Kentucky, 2540
Research Park Drive, Lexington, Kentucky, 40511, USA


The effect of
ammonia in syngas in the concentration range of 100 ppbw ¨C 200 ppmw on
Fischer¨CTropsch reaction over 100 Fe/5.1 Si/2.0 Cu/3.0 K catalyst was studied
at 260 oC, 175 psig, H2/CO = 0.67 and 10 Nl/g-cat/h  in a 1-L slurry phase reactor. The
ammonia added in syngas originates from concentrated ammonia and ammonia
nitrate soution. Three concentrations of ammonia in syngas feed,  i.e. 100 ppbw, 20 ppmw and 200 ppmw, were
employed to examine the sensentivty of the iron catalyst to NH3. The
examinion of the impact of each NH3 concentration on the iron
catalyst FTS performance lasted for 144 or 168 h. The results indicated
that  the iron catalyst  was quite resistant to NH3 poisoning
at the FTS conditions used. During 950 h of testing, no changes on the catalyst
selectivities to CH4, C5+ , and CO2, the
selectivities to C4 olefin and paraffin,  and the selectivities to straight C4
olefin and internal C4 olefin was observed. The catalyst
displayed a slight increase in CO conversion while adding 100 ppbw solution in
the first 96 h, which might be partly due to a slight increase in the water-gas
shift activity for the catalyst. Afterwords, the iron catalyst  displayed a stable CO conversion (~56.3%)
regardless of the concentrations of NH3 used.  



* Corresponding author:  Burtron
H. Davis, davis@caer.uky.edu,
: 859-257-0251.