A sponge ball cleaning method has been developed as the technology of scale prevention for the condenser cooling tubes of a thermal power plant. A multi-stage flash type evaporator is made up of many condensers. Therefore, the authors originally thought of the application of sponge ball cleaning method to scale prevention for the condensers of the multi-stage flash type evaporator. In this paper, the authors have made a study for not only pointing out technical problems in the application of sponge ball cleaning method to the multi-stage flash type evaporator but making clear its scale prevention effect as well. As the result of this study, the authors have come to the following conclusions: (1) The sponge ball cleaning method is very effective on scale prevention for the condensers of the multi-stage flash type evaporator.(2) The thermal loss resulting from the extraction of hot brine as a ball carrier can be reduced to a negligible degree by making optimum the extraction quantity of the brine.(3) To make the sponge ball cleaning method effective on scale prevention in the multi-stage flash type evaporator, the sponge ball recycling system should be divided into the following two routes; one is the high temperature zone route and the other one is the low temperature zone route.
An investigation was made on the desorption of uranium from titanium-activated carbon composite adsorbent with mixed eluent of Na2CO3 and Na2HCO3. The rate of desorption of uranium from the adsorbent in the batch process depended on the composition of eluent and temperature. The rate of desorption showed an increase as the ratio of NaHCO3 to Na2CO3 was increased or the temperature was raised. In the column process with the mixed eluent of 0.5N Na2CO3 and 0.5N Na2CO3 at an ordinary temperature, the rate of desorption of uranium did not vary in the range of adsorbent/eluent ratio below 20% and initial uranium concentration of eluent less than 15ppm. Under these conditions, the eluent was found to be re-usable without a decrease in the rate of desorption. From these results, the application of multistage desorption process was discussed. The dissolution of titanium from adsorbent was less than 0.15%. The adsorbent, which was regenerated by washing with 0.1N HCl after desorption, was found to be re-usable.
The 508 A resin has been synthesized by using tetraethylenepentamine, epichlorohydrine and 5-nitro-2-aminophenol as starting materials. The amount of uranium adsorbed in natural seawater is 930μg/g of this synthesized resin. The major factor of the adsorbing property is supposed to be the coaction of_??_and macrocycloimide.
In order to determine automatically the magnesium ion of salt manufacturing samples, the authors made an investigation on Technicon's auto-analyzer by the colorimetric method with xylidylblue-II reagent, and then examined the effects of ethanol concentration of sample solution and of coexisting ions. The following were the results obtained from this study: 1) The reaction between magnesium ion and xylidylblue-II reagent is influenced by the alcoholic concentration. Therefore, it is necessary to control the alcoholic concentration to 54%(the final content). 2) Interference by the coexisting ions such as Na+ and Ca2+can be eliminated by the addition of G-EDTA reagent. In this method, a linear relationship is obtained between the absorbance and the concentration of magnesium ion in the range of 0-20mg/l. This method has the same accuracy as the conventional EDTA method, and can analyze continuously 15-20 samples per hour.
The authors made an investigation on Technicon's auto-analyzer by the colorimetric method o-cresolphthalein complexone (o-C.P.C.) reagent to determine automatically the calcium ion of salt manufacturing samples. The analytical method was as follows: After the pH of a sample was controlled with potassium phosphate solution (buffer solution), the o-C.P.C.reagent was added to the sample solution, and then a colored complex was formed. Calcium ion was determined by measuring the color intensity. In this method, a linear relationship was obtained between the absorbance and the concentration of calcium ion in the range of 0-200mg/l. This method has the same accuracy as the conventional EDTA method.The coefficient of varia-tion was below 4%, and the speed of analysis was consecutive 20 samples per hour.