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Materials Technologies for performance improvement of Cooling Systems in Power Plants

Periodic Reporting for period 2 - MATChING (Materials Technologies for performance improvement of Cooling Systems in Power Plants)

Reporting period: 2017-09-01 to 2019-02-28

Power generation is a sector requiring great amounts of water primarily for cooling purposes. At European level, while water is in general abundant, water scarcity still affects some regions in particular during summer. In the Mediterranean area water demand for energy production compete with the demand from agriculture and tourism generating situation of water stress. An improved approach for a sustainable management of water resources is therefore crucial The goal of MATChING is to reduce the cooling water demand in the energy sector through the implementation of innovative technological solutions.
The project target include: a) Reduction of geothermal steam emitted into the atmosphere up to 15% and extension of production wells life up to 10%; b)Overall plant efficiency increase up to 0.5%; c) Overall reduction of fresh water abstraction in power plants of 30%. To reach these target a broad set of technologies are investigated, as indicated in Figure 1, where their application to a typical open recirculating cooling system is shown.
"The project is organized in 8 work packages as indicated in figure 2. WP1 holds the management and coordination actions. WP2 provides the criteria for the evaluation of the technologies developed in WP3-WP6 and supports their economical analysis (WP7). WP3-WP6 are the ""technological WPs"" and are dedicated to the demonstration of the technologies.
WP3 deals with the exploitation of low temperature geothermal source for electricity generation in bynary cycle configuration. The first application case is the geothermal site of Balmatt, in Belgium, where, currently, geothermal brine is used for district heating. To maximize the electricity production from the process, without consuming water for cooling, a hybrid configuration based on the use of Ground Water Cooling (GWC) and Air Cooler Condenser(ACC) is investigated through a simulation tool. In addition, as the geothermal brine is a high salinity fluid, to reduce the installation costs, the application of coatings for upgrading the corrosion resistance of cheap materials is experimentally evaluated. At month 36, the design of a binary Organic Rankine Cycle system integrated with ACC and GWC and model optimization and integration with a tool for reservoir dynamic simulation has been completed. Further simulations to compare with cooling tower are planned in the next period. On the coatings side, the experiments in laboratory have been completed. A total of 12 coatings for AISI 316L and 9 coatings for P265G have been tested. Five of them have been selected for the testing at Balmatt site where they will work with the real geothermal brine. Test section at Balmatt is ready to be used for testing the coatings. Start-up of Balmatt is foreseen in April 2019.
WP4 deals with the application of hybrid Cooling Towers to high temperature geothermal plants. The first application case is represented by the Nuova San Martino plant in Italy where 6 traditional wet cooling cells are operating. Within the Project one of them has been retrofitted to host a hybrid cell. A series of experimental investigations were carried out to individuate the best combination of material and coatings for the dry tube bundle as well as the best filling media for an optimized design of the tower. At month 36, the design of the process equipment for the Tower is completed. A total of 8 coatings on two different base materials (Aluminium 6060T, Carbon Steel ASTM A179) have been characterized in laboratory before and after their exposure in by-pass configuration in Nuova San Martino; The best 3 combinations have been chosen for 3 of the 4 exchanger tube bundles. The fourth one will be in AISI 316 L. Two different filling media have been tested in the SPIG facility. One of them has been chosen for the demo. The erection and commissioning of DEMO module was in April 2018. The hybrid demonstration began at M30 (November 2019) after the restoring works due to fire accident and will last up to M40 (June 2019).
WP5 aims at improving steam condenser performances, increasing, at the same time, heat transfer rate and condenser robustness. Different material solutions will be investigated, acting on the steam side, to promote drop-wise condensation, and on the cooling water side, to contrast biofouling phenomenon. All the thermal and nuclear power plants are potential application cases for the technologies developed in WP5. In a first step they will be demonstrated in a pilot condenser that will be installed in the As Pontes Power Station. At month 36 the laboratory test to support selection of coatings/materials for validation, both on the steam side and the cooling water side, have been completed. For drop-wise condensation five solutions have been selected and tested at THRYCO pilot with promising results for DTI and MateriaNova coatings. Pilot condenser design and installation is completed in As Pontes and the start-up will be in April 2019. On the cooling water side, many coatings and materials have been investigated b"
The technologies developed in the project represent an innovation with respect to the market situation or with respect to the current practice in Industry: hybrid towers are normally applied to thermal sector but not to the geothermal one due to the aggressiveness of the fluid; drop-wise condensation has been studied for years but a series of technological issues together with a moderate interest from the Industry has prevented its market uptake. On the water treatment side, despite of the many technologies present in the market, their application in the power industry is still moderate due to sector specific constraints or technical/economical barriers. Now, thanks also the increasing awareness in Europe on the importance to safeguard water, this situation is going to change. Each of the described technologies contributes to water saving at a different extent but as they are applicable in a synergic way and in all the sectors of electricty production (from renewable to fossil and nuclear) a huge impact is expected from their exploitation.
Figure 2 - Workplan
Figure 1 - Technologies