| 摘要 |
Novel methods of providing fuels to a gas-to-liquids facility are disclosed. A gas-to-liquids facility typically operates in a remote location and therefore must supply its own energy needs. These facilities are often sustained by fuels having different heating values, and for smooth operation while transitioning from one fuel to another, (such as during startup, shut down, and emergencies) the Wobbe Indices of the two fuels cannot greatly vary from one another. According to embodiments of the present invention, the Wobbe Index of either or both of the fuels is adjusted such that their ratio is less than or equal to about 3. The fuel having the higher Wobbe Index may be natural gas, and materials such as nitrogen, carbon dioxide and flue gas may be added to lower its Wobbe Index. The fuel having the lower Wobbe Index may be the tail gas of a Fischer-Tropsch synthesis, and materials such as methane, ethane, LPG, or natural gas may be added to raise its Wobbe Index. Alternatively, carbon dioxide may be removed from the tail gas to raise its Wobbe Index.
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