(111c) Experimental Investigation of Liquid Fuel Production From Derived Synthesis Gas Via Fischer-Tropsch Synthesis

Due to the recent surge in energy costs and uncertainties in fuel prices, there is significant interest in seeking alternative sources of energy particularly from renewable such as biomass. Biomass-to-Liquid (BTL) processes via the thermo-chemical conversion of biomass to syngas followed by liquefaction using Fischer-Tropsch Synthesis (FTS) offers a commercially viable route for meeting the challenge of producing renewable fungible liquid fuels.  

 FTS technology is well established and commercial for syngas derived from coal (CTL) as well as for syngas produced from natural gas (GTL). However, to the best of our knowledge, no commercial facility exists for BTL processes. The objective of this paper is to present results obtained from a bench-scale catalytic fixed bed reactor for converting syngas derived from pine wood chips to liquids. Again to the best of our knowledge, no one has reported results for liquefying bio-derived syngas. Pine chips were subjected to an entrained flow gasification process developed by Pearson et al. [1].  The resulting gas contained mainly carbon monoxide, hydrogen, carbon dioxide, methane and some organic contaminants such as benzene, toluene, and naphthalene along with substantial amount of water.  This gas was cleansed using multiple adsorbents to remove tars and water. An inline “Shaw Moisture Meter” was used to continuously monitor the moisture content of the feed to the liquefaction process.

In prior research we developed an egg-shell cobalt catalyst supported on silica for  selectively producing larger fraction of middle distillates (diesel and aviation fuel). This catalyst was packed with some inert silica particles in a fixed bed bench scale reactor approximately 1 in in diameter and 12 inches long. This eggshell design balances the diffusional limitations with residence time requirements to achieve higher middle distillate production. In this regard previous research work conducted by Iglesia et al. was also consulted [2]. Modeling of the reactor startup and of adjustment of the reactor packing ensured successful operation resulting in a high conversion and narrow distribution of hydrocarbons in the range of diesel and aviation fuel.

 References:

[1] Pearson et al., U.S. Patent 4,857,076, issued Aug 15, 1989.

[2] E. Iglesia, S. L. Soled, J. E. Baumgartner, S. C. Reyes, J. Catal. 153, 108 (1995).