| 摘要 |
A method (and apparatus) is disclosed for the spectroscopic determination of the amount (alpha)Nn of one constituent N of a fluid mixture 0 in another constituent n of the mixture, following separation of the mixture into its constituents 1,..., M (where n, N<=M). The method involves determining the absorptivities an (n=1,...,N) of the M constituents from spectroscopic measurements and computing the amount (alpha)Nn from a mathematical expression containing the absorptivities an and aN which are expressed or expressible as the quotient an/aN only. The method is insensitive to changes in the absorptivities due to feed variability or changes in upstream process conditions, since any changes in the numerator and denominator of the quotient used are affected correspondingly. A modification to the method involves determining the content (alpha)N0 of constituent N in feed 0 from a mathematical expression containing a0, where a0 is the absorptivity of the feed 0, and aN, which absorptivities a0 and aN are expressed or expressible as the quotient a0/aN only.
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