Fischer-Tropsch process alcohol from coal

Sasol Fischer-Tropsch Process. 1-Propanol is one of the products from Sasol s Fischer-Tropsch process (7). Coal (qv) is gasified ia Lurgi reactors to produce synthesis gas (H2/CO). After separation from gas Hquids and purification, the synthesis gas is fed iato the Sasol Synthol plant where it is entrained with a powdered iron-based catalyst within the fluid-bed reactors. The exothermic Fischer-Tropsch reaction produces a mixture of hydrocarbons (qv) and oxygenates. The condensation products from the process consist of hydrocarbon Hquids and an aqueous stream that contains a mixture of ketones (qv) and alcohols. The ketones and alcohols are recovered and most of the alcohols are used for the blending of high octane gasoline. Some of the alcohol streams are further purified by distillation to yield pure 1-propanol and ethanol ia a multiunit plant, which has a total capacity of 25,000-30,000 t/yr (see Coal conversion processes, gasification). 

Development of SASOL. Over 70% of South Africa s needs for transportation fuels are being suppHed by iadirect Hquefaction of coal. The medium pressure Fischer-Tropsch process was put iato operation at Sasolburgh, South Africa ia 1955 (47). An overall flow schematic for SASOL I is shown ia Figure 12. The product slate from this faciUty is amazingly complex. Materials ranging from hydrocarbons through oxygenates, alcohols, and acids are all produced. 

The Fischer-Tropsch process was developed by F. Fischer and H. Tropsch in 1921 to produce clean alternative fuel from coal, natural gas, and low-grade refinery products for use in automobile and diesel engines. The process entails the synthesis of hydrocarbons and other aliphatic compounds, such as alcohols, from a mixture of hydrogen and carbon monoxide (synthesis gas, or syngas). The following equation illustrates the chemical reactions involved in the process ... 

The hydroformylation of alkenes was accidentally discovered by Roelen while he was studying the Fischer-Tropsch reaction (syn-gas conversion to liquid fuels) with a heterogeneous cobalt catalyst in the late thirties. In a mechanistic experiment Roelen studied whether alkenes were intermediates in the "Aufbau" process of syn-gas (from coal, Germany 1938) to fuel. He found that alkenes were converted to aldehydes or alcohols containing one more carbon atom. It took more than a decade before the reaction was taken further, but now it was the conversion of petrochemical hydrocarbons into oxygenates that was desired. It was discovered that the reaction was not catalysed by the supported cobalt but in fact by HCo(CO)4 which was formed in the liquid state. 

Considerable attention has been paid to the application of CNTs as the catalyst support for Fischer Tropsch synthesis (FTS), mainly driven by utilization of the confinement effect (Section 15.2.3). In general, this process is a potential alternative to synthesize fuel (alkanes) or basic chemicals like alkenes or alcohols from syngas, which can be derived from coal or biomass. The broad product spectrum, which can be controlled only to a limited extent by the catalyst, prohibited its industrial realization so far, however, it is considered an important building block for future energy and chemical resource management based on renewables. 

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