{HEAD ~ The direct introduction} of hot low temperature carbonization gases from which the dust has been extracted has {TAIL ~ the advantage} of avoiding reactions between the low temperature carbonization gas and the carbon vehicle situated above the reaction bed, since such reactions might reduce efficiency and the gas yield 
has
{ HEAD ~ The direct introduction } of hot low temperature carbonization gases from which the dust has been extracted has { TAIL ~ the advantage } of avoiding reactions between the low temperature carbonization gas and the carbon vehicle situated above the reaction bed , since such reactions might reduce efficiency and the gas yield
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