TY - CONF
TI - PRO and SWRO experimental synergy: a renewable nexus in the Caribbean
AU - Cala, A
AU - Marchena, R
AU - Maturana, A
T2 - Pan American Marine Energy Conference (PAMEC 2024)
AB - Seawater desalination through reverse osmosis (RO) has emerged as a global solution to meet the escalating demand for water, particularly in regions grappling with freshwater scarcity [1], [2]. Despite its widespread adoption, challenges such as membrane fouling susceptibility and high energy demands persist, fueled predominantly by fossil fuels [3], [4], [5].The current specific energy requirements for RO seawater desalination, ranging from 1.5 to 4 kWh/m³, contribute to elevated operational costs [6]. Efforts to enhance operational efficiency have focused on innovative membrane materials, energy-efficient processes, and effective pretreatment methods [7], [8], [9], [10]. Despite advancements, the economic costs of seawater desalination remain high, prompting exploration into alternative technologies. One promising avenue involves coupling reverse osmosis with Pressure Retarded Osmosis (PRO), a process generating electricity by mixing fluids with different salinity concentrations [11], [12]. This coupling aims to coproduce water and energy, reduce process costs, and utilize brine resulting from the RO process. Integration of RO and PRO technologies has demonstrated increased energy generation, potentially producing up to 50% more water than conventional systems [13], [14], [15]. However, large-scale commercial implementation requires further research and development [16], [17], [18]. Various studies have explored the potential of RO-PRO hybrid systems, highlighting benefits in water and energy management, energy savings, and environmental advantages [14], [16], [19], [20], [21], [22], [23]. These findings emphasize the relevance and potential of hybrid RO-PRO systems in desalination, providing a glimpse into their practical application. In a pilot plant using RO brine, attractive long-term operating costs were achieved with average power densities ranging from 1.1 to 2.3 W/m² [24]. Various RO-PRO configurations have been assessed, revealing sensitivity in energy costs when coupled with seawater RO [19].Combining RO/PRO demonstrated a reduction in RO input power by up to 38% [25]. However, a different study reported 50% higher energy consumption in RO-PRO compared to two-stage RO [14]. Noteworthy RO/PRO projects include the Mega-ton hybrid plant in Japan and the Korean Global MVP project. Using treated freshwater and RO brine, Mega-ton achieved a maximum power output of 13.8 W/m² [26]. The Korean project, employing MED, RO, and PRO, reduced brine by 30% and produced a power density of 7.5 W/m² [27], aiming to recover energy and water from brine. Some authors propose that the hybrid RO-PRO configuration is advantageous in seawater applications compared to PRORO, citing the use of RO brine as a draw solution in PRO, leading to a more significant salt difference and improved overall energy efficiency. Additional factors include produced water quality, energy cost reduction, design flexibility, membrane wellness, and waste management [28] Therefore, this study uniquely examines produced water quality and energy cost reduction on a lab scale. In the complex scenario of the Colombian Caribbean, this work embarks on an ambitious endeavor: the experimental assessment of seawater desalination by RO and salinity gradient energy (SGE) production by PRO technology. While RO/PRO experimentation is established, the Colombian Caribbean conditions present a new frontier for these technologies due to regional water quality, site-specific potential, and local service costs. Moreover, the Caribbean Region confronts formidable water and energy supply challenges, with irregular access to potable water and a growing demand for nonrenewable sources [29], [30]. The drinking water supply, solely dependent on the Magdalena River, must be revised, particularly during emergencies like river spills [31]. Amid these challenges, the prospect of integrating seawater desalination and SGE through RO/PRO technology emerges as a paradigm shifting opportunity, considering the unprecedented potential for harnessing sustainable energy and freshwater resources in this region [32]. This study provides detailed information on two proposed lab-scale configurations between RO and PRO (RO-PRO and PRO-RO), offering a comprehensive initial view of these technologies through methodical experimental design, statistical analysis, and power density estimations using natural water samples. The results enable a comparison of configurations, and upon evaluating criteria encompassing energetic, water production quality, and synergic performances, the suggested option for the region's conditions is determined.View the Conference Paper here.View the Presentation Slides here. 
DA - 2024/02//
PY - 2024
SP - 9
UR - https://pamec.energy/events/pamec2024/conference-program/
LA - English
KW - Salinity Gradient
KW - Pressure-Retarded Osmosis
KW - Lab Data
ER -