Long bypass scheme

To circumvent such problems, up to two-thirds of the acid gas has been removed from the flame and sent directly to the catalytic reactor, the so-called "long bypass" scheme. This strategy has worked with mixed success in natural gas plants, where hydrocarbons in the acid gas are C1-C3 paraffins, chiefly methane, and no olefins. Such a configuration has been put forward for use in coal gasification plants. In the writer s opinion it is unworkable if the bypassed acid gas contains even traces of olefins or aromatics these compounds react with SO2 to form tarry products which foul the catalyst and discolor the product sulfur. 

Marcus (2004) hypothesized that CAI formation through surface oxidation can lead to 160 enhancements in solid products. This silicate-forming oxidation process bypasses the drawback of very low densities (and thus long timescales) for gas-phase recombination reactions under nebular conditions. The reaction scheme is displayed in Fig. 4.10. 

Welsh Office are at present preparing proposals for a relief motorway which would bypass Newport to the south and provide a long term solution to the problems posed by the features of the current motorway not being to current standards and its limited capacity. This scheme is subject to the roads review announced by the Secretary of State in July last year. The outcome of this review is expected to be announced later this year. 

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