DEmonstration of concentrated SOLar power coupled wIth advaNced desAlinaTion system in the gulf regION.

Project Information

DESOLINATION

Grant agreement ID: 101022686

DOI

10.3030/101022686

EC signature date 16 April 2021

Start date 1 June 2021

End date 30 September 2026

Funded under

• SOCIETAL CHALLENGES - Secure, clean and efficient energy

Total cost

€ 13 826 780,07

EU contribution

€ 9 995 214,75

Coordinated by

POLITECNICO DI MILANO
Italy

Periodic Reporting for period 2 - DESOLINATION (DEmonstration of concentrated SOLar power coupled wIth advaNced desAlinaTion system in the gulf regION.)

Reporting period: 2023-08-01 to 2025-01-31

Summary of the context and overall objectives of the project

The coupling of CSP with desalination has faced the challenge of being competitive from economic point of view mainly because of its high capital costs. The DESOLINATION project will develop and demonstrate disruptive strategic innovations on CSP, on desalination, and on their coupling.
DESOLINATION builds an energy-efficient demonstrator prototype based on a current and an innovative power cycle, while optimising each individual component of the global system. Bringing together two promising technologies for the first time associated in a low energy consumption CSP+D pilot plant, the DESOLINATION system will show high wasted heat- to-freshwater conversion efficiency as well as high CSP power efficiency (>42% at 550°C) leading to an LCOE below 90€/MWh and LCOW below 0.9€/m3 at 100MW scale.
The technology will be demonstrated at relevant scale and the first of a kind power block with a net power output of 1.8 MWel will be installed and tested at King Saudi University.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Significant progress was made in modelling, testing, and optimizing the CO2-SO2 power cycle for the pilot plant. Dynamic simulations using Aspen Plus Dynamics provided crucial insights into transient behaviour. Experimental reliability testing of heat exchangers confirmed strong thermal performance. In addition, material compatibility tests identified corrosion-resistant alloys with superior resistance at 550°C, ensuring long-term durability of high-temperature components. Ongoing work focuses on validating dynamic turbomachinery models using industry partners data and integrating a full transcritical cycle loop.

On the water side, FO experiments were performed using Aquaporin hollow fibre HFF02 and TOYOBO hollow fibre membrane. Three thermo-responsive polymers Unilube 50MB-26, Pluronics L-35 and Polycerin55Gl-2601 tested as draw solution (DS) with 3.5Wt.% NaCl as feed. Experiments were also carried out by adding three different salts i.e. MgCl2, CaCl2 and NaCl to the polymeric DS to increase the osmotic pressure and eventually the FO performance. Based on the results, the design of the demonstration plant has been carried out.
For VMD, tubular ceramic membrane was tested for varying feed concentration (3.5 - 14 Wt.% of NaCl) and feed temperature (60 – 80°C).
Furthermore, NF experiments were performed for water-rich phase of the diluted DS having 2 Wt.% concentration of Unilube 50MB-26 by commercial flat sheet NF90 membrane from DuPont.
Testing of a coalescer separator with a thermo-responsive draw agent (PAGB2000), with three different metal meshes used to increase the coalescence effect and obtain an efficiency formulation.
FO Layer-by-layer membranes and high-flux asymmetric α-alumina ceramic membranes are being developed and are ongoing pilot testing.
Development of a novel brine mining process involving multi-crystallisation and demonstrating high recovery and purity of salts including Mg(OH)2, Ca(OH)2, NaCl and Li2CO3.

The optimal configuration was identified with Forward Osmosis and Nanofiltration for the final purification, Membrane distillation to increase the recovery ratios up to 85% and the final brine treatment with mineral recovery. The overall Specific Energy consumption is below 100 kWh/m3 as planned. The recuperative heat exchanger was also designed and manufactured.
The container for the Adaptive Coupling System (ACS) has been designed, 3D modelled, built and shipped. The desalination system has been designed and is in the final stage of 3D design. Manufacturing is scheduled to begin in early March 2025. The molten salt system is in the final design stage.
Preparation and management of the site to host the sCO2 cycle components, adaptative and desalination systems and related structures, also managing integration with existing KSU facilities. Preparation of power supply required, thermal insulation of ducts, water supply/discharge are in progress.
A new platform to host the Heat Recovery Exchanger (HRE) has been constructed.
Education and students training in Sustainable power and desalination technologies using solar and CO2. This includes the discussion of a MSc project in June 2024 on PTC coupled with sCO2 cycle for various Saudi climates; Also, students’ projects on solar CO2 power, desalination with storage in the frame of BSc, MSc and PhD courses.
The complete plant assessment methodology has been defined, including the baseline of a conventional reference system of CSP + Desalination, the scope of the LCA and boundary system, and the running of case studies in Saudi Arabia, Oman, and Bahrain for social impact definition.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

On the solar side, the pilot plant achieved thermal efficiency of 30% at a maximum pressure of 200 bar. Sensitivity analysis indicates that increasing the turbine inlet pressure by 10 bar or temperature by 10°C results in a 0.5% efficiency improvement. The estimated specific overall cycle cost (OCC) is $1900/kWe for a 1.8 MWe system. Long-term material testing validated suitability and long-term component reliability of the alloys and CO2-SO2 blend. Experimental validation demonstrated high thermal performance, though modifications are required to reduce pressure losses in gyroid heat exchangers.
On the water side, significant results were brought to the coalescer and increase of the FO flux through the membrane was tested through three thermo-responsive polymers while an alternative polymer will also be tested in the upcoming work. It was also found that FO performance depends on the osmotic pressure gradient for water flux and diffusion-driven reverse solute flux, which is influenced by concentration and flow conditions. A newly developed method for determining PAG osmotic pressure based on equilibrium correlations with NaCl and more reliable than freezing point osmometry and will be considered in future research. ZLD brine recovery technology achieved near 100% water recovery and will be used for various types of brines (seawater, solar, geothermal, oilfield).
An innovative desalination lay-out was developed achieving very high recovery ratios with low specific energy consumptions. The optimal coupling between CSP and desalination was identified with optimal combination between the different membrane separators.
WPs5-8 have laid the land for the upcoming demonstration and impact assessment of the technology, ensuring proper CSP-desalination integration and enhancing positive techno-economic, environmental and social impacts.

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