TIGAS process

The SPARG process is preferred when cheap C02 is available, whereas autothermal reforming requires cheap oxygen to be competitive. Two-step reforming (ref. 6) i.e., tubular reforming with autothermal reforming as a second step, may be a favorable solution in some cases, for instance, for the TIGAS process (ref. 7). 

TOPS0E INTEGRATED GASOLINE SYNTHESIS - THE TIGAS PROCESS J. TOPP-J0RGENSEN... 

Consequently, further development of the MTG process as it is realised in New Zealand should aim at a reduction of the investment. The TIGAS process represents such an effort. In the TIGAS process the two process steps, MeOH synthesis and the MTG process, are integrated into one single synthesis loop without isolation of MeOH as an intermediate (ref. 1), (Fig. 1). 

Fig. 1. Gasoline from natural gas with the TIGAS process...

Fig. 10. Octane No. s of the gasoline product frcm the TIGAS process as a function of the hydrogen partied pressure in the synthesis loop.

The octane number of the gasoline product from the TIGAS process will depend on the process layout. Especially the hydrogen level in the loop will influence the octane number (Fig. 12). The highest research octane numbers observed have been a few numbers lower than those obtained in the MTG process (ref. 9), whereas the motor octane numbers are similar. The reduced octane number, which is the result of the low olefinic content in the gasoline, is the penalty to be paid for the benefits obtained by integration. The size of the penalty will depend on the end use of the product from a TIGAS plant, the octane requirements at the specific location and the extent to which octane improvers are available and acceptable. 

In the TIGAS process [492] [261] the two loops are combined (Figure 2.28), resulting in a simpler and cheaper process layout. The two process... 

The considerations for methanol production are valid also for manufacture of synfuels. The manufacture of synthetic gasoline by the Mobil MTG (Yurchak, 1988) or Topsoe TIGAS process (Topp-Joergensen, 1988) proceeds via methanol or dimethylether as intermediate. Diesel can be manufactured by the Fischer-Tropsch synthesis followed by hydrocracking of the wax product (v.d. Burgt et al., 1988). Slurry b Fischer-Tropsch processes for diesel may operate at a Hj/CO ratio slightly lower than for methanol synthesis (Dry, 1988). 

Figure 15 shows simplified flow schemes of the two alternatives. The indirect route to methanol is based on steam reforming followed by methanol synthesis. The process consumes ca. 7 Gcal/t corresponding to a thermal efficiency of 68%. The synthesis gas route may also lead to gasoline by further conversion of methanol via the Mobil MTG-process (Yurchak, 1988) or by the Topsoe TIGAS process (Topp-Joergensen, 1988). 

The indirect routes are self-sufficient in energy and have no steam export. The direct route has a heat production comparable to that of the TIGAS process, but only part of the heat may be required for down-stream processes and recycle, whereas the rest must be exported as steam. 

TIGAS [Topsoe integrated gasoline synthesis] A multi-stage process for converting natural gas to gasoline. Developed by Haldor Topsoe and piloted in Houston from 1984 to 1987. Not commercialized, but used in 1995 as the basis for a process for making dimethyl ether for use as a diesel fuel. 

Two major versions of the MTG process currently exist. The first, as exemplified by the New Zealand GTG configuration, is a fixed-bed process the second is a fluidized-bed process. A third process concept, the Topsoe TIGAS [40], integrates methanol synthesis with MTG. This variation uses a multifunctional catalyst for producing a mixed oxygenate feed (including methanol) from synthesis gas and was tested... 

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