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Treatment of Wastewater to Meet the Requirements for Cooling Water Systems in Jordan’s Nuclear Plants

Aiman Eid Al-Rawajfeh Kamal Araj
Chemical and Process Engineering | 2013 | No 2 June | 253-267 | DOI: 10.2478/cpe-2013-0021
Keywords cooling water nuclear plants wastewater treatment scale deposition
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Abstract

Scaling and corrosion associated with the use of natural hard water in cooling towers during recirculation pose great problems from both economical and technical points of view, such as decreased system efficiency and increased frequency of chemical cleaning. Treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. In this work, hybrid systems of salt precipitation (SP), nanofiltration (NF) and reverse osmosis (RO) were investigated, as potential pretreatment processes for wastewater reuse as cooling water in the planned Jordan nuclear power plants. The As-Samra wastewater was used to calculate the potential of carbonate and sulfate scale formation. The results were compared to scale potentials from Palo Verde wastewater. Four cases were investigated; SP, NF, SP-RO and NF-RO. The SP pretreatment cases showed the highest monovalent to divalent ratio because of a high removal of Ca and Mg and addition of Na from the chemicals of the SP step. The NF pretreatment cases, showed the lowest calcium sulfate scale potential and this potential decreases with the % pretreatment. The scale amount increases very slightly with concentration times when the SP and NF product is desalinated by RO step.

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Authors and Affiliations

Aiman Eid Al-Rawajfeh
Kamal Araj

Cooling water flow influence on power plant unit performance for various condenser configurations setup

Ewa Dobkiewicz-Wieczorek
Archives of Thermodynamics | 2022 | vol. 43 | No 1 | 141-167 | DOI: 10.24425/ather.2022.140929
Keywords Cooling water Power plant efficiency Cooling water flow control CHP plant efficiency
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Abstract

This paper presents the influence of cooling water regulation on power plant net efficiency. It was examined whether, for the non-nominal low-pressure turbine load, it is justified to reduce the cooling water pump load, and how it would affect the unit net efficiency. Calculations for two types of power units were carried out: with condensing and extractioncondensing turbine. The tested condensing power plant consists of three surface condensers. The calculation included four condensers’ connections set up on the cooling water side to check how the cooling water system pressure drop affects the net unit performance. The result has confirmed that implementing serial connection decreases net efficiency when cooling water flow regulation is used, but the mixed connection should be applied when pump load is not controlled. It was proved that the cooling water flow control gives a profit for both units. Net efficiency for combined heat and power plant can be improved by 0.1–0.5 pp, the gain is remarkable below 60% of the low-pressure turbine part load. Flow control implementation in the unit with condensing turbine water control gives a similar profit just below 80% of the turbine load. Next, an influence of the additional limitations of a cooling water system (minimal total pump head, cooling tower) affecting the feasibility of implementing the water control has been considered. Applying a multi-cell forced draft cooling tower does not have a significant impact on results, but when a natural draft cooling tower is used, the flow control range is strongly reduced.
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Bibliography

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Authors and Affiliations

Ewa Dobkiewicz-Wieczorek
1
  1. Silesian University of Technology Department of Power Engineering and Turbomachinery, Konarskiego 18, 44-100, Gliwice, Poland

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