Assessment of Advanced Process Concepts for Liquefaction of Low H sub 2 :CO Ratio Synthesis Gas Based on the Koelbel Slurry Reactor and the Mobil-Gasoline Process

摘要

The Koelbel reactor is a three-phase Fischer-Tropsch reactor in which synthesis gas is passed upward through a slurry of finely divided catalyst in a heavy oil medium and products are removed overhead. Koelbel claimed that this reactor configuration allowed the processing of synthesis gas with low H sub 2 :CO ratios at high single-pass conversion with excellent temperature control and without the rapid aging because of carbon deposition normally encountered with such feeds in other reactor types. These reactor characteristics might thus allow conversion of the low H sub 2 :CO ratio output from second-generation coal gasifiers directly without preliminary water-gas shifting and without extensive recycle. Such operation should result in improved thermal efficiency and decreased processing costs. However, the product distribution reported was relatively conventional for Fischer-Tropsch performance so that the need for octane improvement for gasoline production would still exist. The Mobil-Gasoline process converts methanol to high-octane gasoline in high efficiency. There are recent indications that the shape-selective zeolite catalyst used might also accept crude Fischer-Tropsch products as a feed instead of methanol. Conceptual combination of all these observations leads to an advanced indirect liquefaction scheme for coal consisting of a second-generation gasifier coupled to a slurry Fischer-Tropsch reactor coupled to a Mobil-Gasoline upgrading unit. This concept is developed further, but it is noted that other investigators have had some difficulty in repeating Koelbel's very favorable results. (ERA citation 05:012962)