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One of the simplest approaches to eliminating refining and reducing costs of Fischer-Tropsch (FT) liquids is to use wide-boiling point cuts resulting in a fuel that has a T10 volatility similar to that of gasoline. Wider boiling point cuts may also result in fuels having larger fractions of waxy components. The role of blend stocks is important in evaluating the feasibility of using FT liquids as fuels due to these waxy components. This paper compares the performance of FT liquids, FT diesel, petroleum diesel, and multiple blended fuels in a VW 1.9L TDI to evaluate the feasibility of direct use of FT liquids.

Cold flow properties have historically been important for diesel and jet fuels. Reflecting the importance of cold flow properties, several standards have been developed to characterize pour point, cloud point, and filterability. An emphasis on characterizing fuels based on standard testing methods has led to large amounts of data that describe how fuels perform but very little published data that describe what is happening at the molecular level and to the composition of fuels. Motivated by a desire to have an improved understanding of the cold flow behavior of Fischer-Tropsch fuels, an experimental method was developed to provide easy acquisition of data on the changing compositions of liquid and solid phases as Fischer-Tropsch and diesel fuels traverse cloud point, pour point, and additive-enhanced pour point temperatures.

Fischer-Tropsch (FT) conversion of gasification products to liquid hydrocarbon fuel commonly includes FT synthesis followed by mild refining of the FT synthetic oil into diesel, kerosene, and naphtha, each defined by a specific boiling range. These FT products are derived typically by mixing condensable gaseous reactor effluent (∼C5-C20) with hydrocracked liquid reactor effluent (∼C20+). This mixture of FT liquids (FTL), is then hydrotreated and distilled to yield the desired products. This paper evaluates compression-ignition engine performance during preliminary tests of the condensable gaseous reactor effluent (∼C5-C20) portion of the (FTL) from a Syntroleum Corporation plant. Engine operability, maximum torque, fuel economy and emissions were evaluated for both FTL and mixtures of FTL with gasoline, hexanes, diethyl ether, and ethanol. Emphasis was placed on particulate and NOx emissions. However, hydrocarbon, carbon dioxide, and oxygen concentrations were also followed.