LIQUID PHASE FISCHER-TROPSCH (III & IV) DEMONSTRATION IN THE LAPORTE ALTERNATIVE FUELS DEVELOPMENT UNIT. Final Topical Report. Volume I/II: Main Report. Task 1: Engineering Modifications (Fischer-Tropsch III & IV Demonstration) and Task 2: AFDU Shakedown, Operations, Deactivation (Shut-Down) and Disposal (Fischer-Tropsch III & IV Demonstration).

Slurry phase Fischer-Tropsch technology was successfully demonstrated in DOE's Alternative Fuels Development Unit (AFDU) at LaPorte, Texas. Earlier work at LaPorte, with iron catalysts in 1992 and 1994, had established proof-of-concept status for the slurry phase process. The third campaign (Fischer-Tropsch III), in 1996, aimed at aggressively extending the operability of the slurry reactor using a proprietary cobalt catalyst. Due to an irreversible plugging of catalyst-wax separation filters as a result of unexpected catalyst fines generation, the operations had to be terminated after seven days on-stream. Following an extensive post-run investigation by the participants, the campaign was successfully completed in March-April 1998, with an improved proprietary cobalt catalyst. These runs were sponsored by the U. S. Department of Energy (DOE), Air Products & Chemicals, Inc., and Shell Synthetic Fuels, Inc. (SSFI). A productivity of approximately 140 grams (gm) of hydrocarbons (HC)/ hour (hr)-liter (lit) of expanded slurry volume was achieved at reasonable system stability during the second trial (Fischer-Tropsch IV). The productivity ranged from 110-140 at various conditions during the 18 days of operations. The catalyst/wax filters performed well throughout the demonstration, producing a clean wax product. For the most part, only one of the four filter housings was needed for catalyst/wax filtration. The filter flux appeared to exceed the design flux. A combination of use of a stronger catalyst and some innovative filtration techniques were responsible for this success. There was no sign of catalyst particle attrition and very little erosion of the slurry pump was observed, in contrast to the Fischer-Tropsch III operations. The reactor operated hydrodynamically stable with uniform temperature profile and gas hold-ups. Nuclear density and differential pressure measurements indicated somewhat higher than expected gas hold-up (45 - 50 vol%) during Fischer-Tropsch IV operations. The high gas hold-up was confirmed by a dynamic gas disengagement test conducted at the end of the run. Heat transfer in the reactor was better than expected. Heat, mass and elemental balance calculations indicated excellent closure. After the initial learning curve with system dynamics, the plant was restarted very quickly (24 hours and 17 hours) following two plant trips. This demonstrates the ease and flexibility of the slurry technology. In-situ reduction of catalyst pre-cursor was completed successfully during F-T IV operations. Water measurements proved to be inaccurate due to wax/oil contamination of the analytical system. However, the reduction appeared to proceed well as close to expected syngas conversion was obtained at the beginning of the run. The selectivity to wax was lower than expected, with higher methane selectivity. Returning to the baseline condition indicated a productivity decline from 135-140 to 125-130 gm HC/hr-lit. of reactor volume in two weeks of operation. This may be a result of some catalyst loss from the reactor as well as initial catalyst deactivation. Significant quantities of product and samples were collected for further processing and analysis by the participants. Gas, liquid and solid phase mixing were studied as planned at two operating conditions using radioactive materials. A large amount of data were collected by ICI Tracerco using 43 detectors around the reactor. The data are being analyzed by Washington University as part of the Hydrodynamic Program with DOE