Desulfurisation reactor

The FT synthesis was conducted at temperatures between 180-200°C, slightly below the range considered to be of commercial interest at present. A process limitation related to the low operating pressure most of the reactors were run at atmospheric pressure. A few plants included reactors designed for operation at pressures of up to 10 bar. Ifie S5mthesis gas in these plants was desulfurised to ca 5 ppm sulfur to protect the FT catalyst (7). As a consequence, and as it is the case at present, all the FT products had very low sulfur contents. 

Seo ct al. reported on the development and operation of a 100-kW natural gas fuel processor, tvhich tvas developed for a molten carbonate fuel cell [609]. The molten carbonate fuel cell does not require any carbon monoxide clean-up (see Section 2.3.2), and thus the system consisted merely of a burner to supply the steam reformer, a compressor, heat-exchangers, the desulfurisation stage and the reformer itself. The reformer was built by relying on conventional technology with tubular reactors top-fired externally from the natural gas burner. The 16 steam reformer tubes shown in Figure 9.33 were operated at a S/C ratio of 2.6 and 3-bar pressure, while the design operating temperature was 700 °C. Seo et al. reported that the efficiency of their system was still too low. Therefore, an improved version of the fuel processor is under development. 

Meyer et cd. described the development of a multi-fuel processor by International Fuel Cells, LLC [627]. Methanol and gasohne (quality California reformulated gasoline grade II) were the major fuel alternatives. The technology chosen consisted of feed desulfurisation, autothermal reforming and catalytic carbon monoxide removal by two water-gas shift stages and two preferential oxidation reactors. The system had a power equivalent of 50 kW. However, performance data were only provided with respect to the autothermal reformer Desulfurisation proved to increase the reformer conversion up to 98%. No residual heavy hydrocarbons then remained in the product. The hot spot of the autothermal reformer approached 1000 °C. 

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