TITLE: Fischer-Tropsch Synthesis from a Low H sub 2 :CO Gas in a Dry Fluidized-Bed System. Volume 2. Development of Microreactor Systems for Unsteady-State Fischer-Tropsch Synthesis. Final Technical Report.

AUTHOR: G. K. Whiting;   Y. A. Liu;   A. M. Squires.

INST.  AUTHOR: Virginia Polytechnic Inst. and State Univ., Blacksburg.  Dept. of Chemical Engineering.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1 Oct 86,  458p.

NTIS ORDER NO.: DE87000287/INW

ABSTRACT:

Vibrofluidized microreactor systems have been developed for studies of unsteady-state Fischer-Tropsch synthesis. This development is aimed at preventing carbon deposition on a fused-iron catalyst in a novel reactor called the ''heat tray.'' This reactor involves a supernatant gas flowing over a shallow fluidized bed of catalyst particles. Three systems were built: (1) a vibrofluidized-bed microreactor system for obtaining baseline carbon deposition information under industrially important reaction conditions; (2) a sliding-plug vibrofluidized-bed microreactor system for rapid switching of feed gases in the F-T synthesis; and (3) a cold-flow microreactor model for studying the gas mixing characteristics of the sliding-plug vibrofluidized-bed microreactor. The results show that catalyst defluidization occurred under steady-state synthesis conditions below 395 C using a feed gas of H sub 2 /CO ratio of 2:1 or less. Above 395 C, the probability of hydrocarbon chain growth ( alpha < 0.50 to prevent accumulation of high-molecular-weight species that cause defluidization. Carbon deposition was rapid above 395 C when a feed gas of H sub 2 /CO ratio of 2:1 or less was used. Cold-flow microreactor model studies show that rapid (on the order of seconds), quantitative switching of feed gases over a vibrofluidized bed of catalyst could be achieved. Vibrofluidization of the catalyst bed induced little backmixing of feed gas over the investigated flow-rate range of 417 to 1650 actual mm sup 3 /s. Further, cold-flow microreactor model studies showed intense solid mixing when a bed of fused-iron catalyst (150 to 300 microns) was vibrofluidized at 24 cycles per second with a peak-to-peak amplitude of 4 mm. The development of the microreactor systems provided an easy way of accurately determining integral fluid-bed kinetics in a laboratory reactor. 408 refs., 156 figs., 27 tabs. (ERA citation 12:013029)

REPORT  NUMBER: DOE/PC/50791-T4

CONTRACT  NUMBER: FG22-82PC50791