Bulletin of the Society of Sea Water Science, Japan

Electrodialysis of High-temperatufe and High-concentration solution by Large-scale Apparatus

Electrodialysis of Solutions of Higher Tempereture and Higher Concentration with Ion Exchange Membranes (II)

Yoshinobu TANAKA, Tsugio YUYAMA, Noriko YUGI, Takashi YUZURIHARA

1971 Volume 25 Issue 3 Pages 189-197
Published: 1971
Released on J-STAGE: February 19, 2013

DOIhttps://doi.org/10.11457/swsj1965.25.189

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In order to evaluate the electrodialytic concentration method of the waste brine discharged from the multi-stage flash (MSF) evaporation process, the solution of about the same concentration and temperature (30-40°C) as those of the waste brine was prepared, and it was dialyzed by large-scale electrodialysis apparatus (the effective membrane area was 72dm²). The results obtained were asfollows:
1. The concentration and the quantity of the concentrate was about the same as those given by the eiectrodialysis of sea water, under the same current density. On the other hand, the cell voltage and the consumption of electric energy indicated a considerable decline as compared to the electrodialysis of sea water, under the same current density. However, an in crease can be expected for them because the current density increases when the waste brine from the MSF evaporation process is electrodialyzed.
2. Ionic products of calcium sulfate and calcium carbonate in the concentrate were considerably less than the solubility product. Therefore, there is little risk for the for mation of scale.
3. During the electrodialysis, the edges of the ion exchange membrane were split by the drying of the margin, and the cation membranes were wrinkled by the expansion and the contraction due to the variation of temperature. However, these troubles were settled by appropriate methods.

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Measurement of Non-equilibrium Temperature Difference in Flash Evaporation Process (Part I)

Kazuo SATO, Kenji KAMIYAMA, Koichi TAHARA

1971 Volume 25 Issue 3 Pages 198-206
Published: 1971
Released on J-STAGE: February 19, 2013

DOIhttps://doi.org/10.11457/swsj1965.25.198

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Some technical methods were studied for the purpose of reducing the non-epuilibrium temperature difference in the flash evaporation process, and a device reducing the pressure by varying the orifice area was designed therefor. This device was installed in a test plant of five-stage flash distillation, and non-equilibrium temperature defferences in the flash evaporation process were measured by using city water.
The results of the study indicated that the rate of evaporation could be increased and the nonequilibrium temperature difference (NTD) could be reduced by making the orifice area larger than the one calculated from the characteristic formula of pressure loss for single phase flow on the same coditions. The following was the emprical equation obtained from the study:
In case the evaporating conditions of a commercial plant were applied to the above equation, the non-equilibrium temperature difference droved to be greater than the calculated values from the AMF's equation for NTD. Therefore, a further study would be necessary on the possibility of scale up by use of the above equation, but the new pressure reducing device was designed in this study.

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[title in Japanese]

[in Japanese]

1971 Volume 25 Issue 3 Pages 207-218
Published: 1971
Released on J-STAGE: February 19, 2013

DOIhttps://doi.org/10.11457/swsj1965.25.207

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