Evidence of axial diffusion accompanied by axial dispersion with zone circulating flow-injection analysis data

Axial dispersion free from any contribution of diffusional effects has been obtained by computer aided simulation with zone circulating flow-injection analysis (FIA) data. The present paper deals with the relationships between axial dispersion and FIA parameters (flow rate, length and inner diameter of the tube, residence time, sample volume, etc.) as well as the relationship between axial dispersion and radial dispersion. Furthermore, the relationship between axial dispersion and residence time, which was ambiguous with the manual analysis, has been cleared up with the computer aided simulation. Analytical expressions already obtained and reported have been analyzed with the computer aided simulation, and constants, K, and exponents, μ, have been determined. DA = K4L1μ′rQ2μ′c + θt (μ′1 ≥ 1, μ′ 2 < 0); K4 = 0.045 ± 0.001, μ′1 = 1.01 ± 0.01, μ′2 = −1.46 ± 0.01. DA = K5Q2μ′ct3μ′ + θt (μ′2 < 0, μ′3 ≥ 1); K5 = 0.076 ± 0.001, μ′2 = −0.42 ± 0.01, μ′3 = 1.02 ± 0.01. (D − 1)(DA − θt) = K7Lr1μ″Q2μ″c (μ″1 < 0, μ″2 ≥ 1); K7 = 7.50 ± 0.01, μ″1 = −0.45 ± 0.01, μ″2 = 1.24 ± 0.01. In the relationship between axial dispersion and radial dispersion, another relationship was also obtained: (D − 1)(DA − θt) = K8Q2μ″ct3μ″ (0 < μ″2 < 1, μ″3 < 0); K8 = 6.70 ± 0.01, μ″2 = 0.75 ± 0.01, μ″3 = −0.48 ± 0.01.