Theoretical studies of flow injection analysis and application for monitoring water quality at power plants with newly developed FI analyzer

The dissertation introduced the development of the Type FIA-Tl-721 Analyzer, and described the function and characteristics of the multistep peristaltic pump with the 8-channel, 3-channel asyn./syn. injection valve and so on. Brief descriptions were given of the main methods that the equipment can support as well as fields of application and the potential of the system (performance data: RSD<0.5%; drift<0.002 A/H; r>0.9999; pump speed: 7.5 similar to 150 (+/-0.5) rpm). Using the analyzer and ZCFIA method, the author had carried out detections at various flow-rates(Q), and obtained many pseudo-damped curves. Analysis of these curves clarified the correlations among the residence time(t), Q, length(L), inner diameter(R), sampling volume(S-v), axial dispersion(sigma) and dispersion coefficient(D). As a result, the author obtained several qualitative Eqs. and conclusions, created a Chinese Crown Model and proposed new concepts of axial dispersion degree (A(D)=S-v,S-z/S-v), radial dispersion density(J(f)=D/A(D)) and the critical time (t(i)). The Eqs. and conclusions can be applied to predict and assess variation tendencies of relationships among sigma Q, L, R, t and D, as well as to optimize experimental conditions in various flow systems. Besides, the author has also researched application of on-line monitoring of the water-steam in power plants, and proposed a dozen FIA methods established with the FIA-Tl-721: simultaneous determination of PO43- and SiO32- in boiler water based on rFIA (0.2 similar to 30 mg/l PO43-, 0.02 similar to 5.00 mg/l SiO32-), FIA on-line concentration determination of trace-level silica in water-steam with ion-exchange resin (3.0 similar to 70 mu g/l SiO32-), catalytic FIA spectrophotometric ultra-micro determination of Cu2+ in water-steam (0.4 similar to 100 mu g/l Cu2+), a new FIA method of determining the exchange-capacity of ion-exchange resin and others.