In actual seawater desalination plant, the pressure loss due to frictional force of pipe is about 3~5 bar. Also, the pressure loss at pipe connection about 1~3 bar. Therefore, the total pressure loss in the pipe is expected to be about 4~8 bar, which translates into 0.111 to 0.222 kWh/m3 of energy when converted into the Specific Energy Consumption(SEC). Reducing energy consumption is the most important factor in ensuring the economics of seawater desalination processes, but pressure loss in piping is often not considered in plant design. It is difficult to prevent pressure loss due to friction inside the pipe, but pressure loss at the pipe connection can be reduced by proper pipe design. In this study, seawater desalination plant piping analysis was performed using a commercial network program. The pressure loss and SEC for each case were calculated and compared by seawater desalination plant size.

Desalination with low energy consumption has been recognized as a crucial technology for meeting the growing freshwater needs of the UAE. In 2016, KAIA and the Masdar company in the UAE signed Joint Development Agreement to develop energy-efficient desalination technologies. The research aims to build a pilot plant desalination plant in UAE for demonstrating reduction of energy footprint. For this R&D project, Daewoo E&C designs and constructs a customized low energy seawater desalination facility with 1000~2000 m³/d by 2018. The goal of specific energy consumption is 3.3 kWh/m³, finally resulting in O&M cost reduction by more than 10%. The system will be configurated with energy saving RO membrane(LG chemistry), pretreatment for algae control using tube type bio filter(MTBF) and DAF, and ion exchange and capacitive deionization for replacement of 2nd RO. Optimizing this pilot plant by 2020 in the UAE is the next milestone in realizing the energy-efficient desalination technology to a viable product.

본 연구는 해수담수화 플랜트의 에너지 사용량을 이론적으로 분석하고 최적화하기 위한 기법을 개발하기 위하여 수행되었다. 먼저 해수담수화 공정모사 모델을 개발하였으며 이를 이용하여 에너지 흐름을 분석하고 각 단계별 유효에너지와 에너지 손실을 계산하였다.

본 연구는 RO 공정을 통한 해수담수화 플랜트의 에너지 저감을 위한 FO/RO hybrid pilot plant 실증 연구에 관한 것이다. 폐수처리 방류수를 이용하여 FO 공정을 통해 해수를 희석시키고, 희석된 해수는 RO 공정을 통해 담수를 생산하는 공정으로 폐수재이용과 저에너지 담수화를 목적으로 하였다. 이 공정은 RO 공정에 유입되는 해수의 염도가 낮아지기 때문에 담수화 에너지를 획기적으로 낮추는 것이 가능하다. 운전된 system은 유입수 기준 1ton/hr의 처리용량을 가 지는 FO/RO hybrid 공정으로 화력발전소 내의 해수담수화 설비내에서 운전하였다. 이를 통하여 기존 RO system 대비 약 20~30%정도의 에너지 소비 저감 효과 및 RO의 fouling 개선 효과가 있음을 확인하였다.