TITLE: Synthesis of octane enhancers during slurry-phase Fischer-Tropsch.  Quarterly technical progress report No. 9, October 1, 1992--December 31, 1992.

AUTHOR: G. Marcelin.

INST.  AUTHOR: Altamira Instruments, Inc., Pittsburgh, PA.

SPONSOR: Department of Energy, Washington, DC.

LANGUAGE: English

PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  30 Jun 93,  19p.

NTIS ORDER NO.: DE93040632INW

ABSTRACT:

Figure 7 summarizes the carbon selectivities observed towards the main products. During Period IV, the main products observed were the heavy hydrocarbons, with selectivity for MTBE being less than 3--5%. The only time that high MTBE selectivity was noted was during period III, when the i-butylene feed was shut-off. The large amounts of heavy products and the low selectivity to MTBE were surprising in view of our previous experiments in the gas phase and the high methanol-to-i-butylene ratio used in these runs. In the gas-phase and with methanol/i-butylene = 0.5, over 95% selectivity to MTBE was observed with this catalyst at this temperature. The higher level of methanol used here would be expected to further improve the MTBE selectivity. Perhaps one reason for the poor MTBE selectivity relates to the relative solubilities of the reactants in the Synfluid changing the effective methanol/i-butylene ratio. Figure 8 shows the relative molar concentration of i-butylene during Period III. At 180 minutes, the gas supply of that reactant was shut-off, yet the analyses show that i-butylene continued to elute from the reactor for at least an additional 2 hours. It seems reasonable that the i-butylene is highly soluble in the Synfluid since they are both nonpolar hydrocarbons.  Likewise, one would expect the methanol to not be quite as soluble and thus the methanol/i-butylene ratio in the liquid medium may be very low, favoring the oligomerization of i-butylene. Indeed, the only time that MTBE selectivity was high was after the i-butylene supply was shut-off. We intend to quantify these solubilities in future experiments.

REPORT  NUMBER: DOE/PC/90047-T7

CONTRACT  NUMBER: AC22-90PC90047