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ENERGIX-Stort program energi

Modeling of high temperature, high pressure geothermal energy production system

Alternative title: Modellering av geotermisk energiproduksjonssystem med høyt trykk og høy temperatur

Awarded: NOK 3.0 mill.

A significant source of renewable energy is hot water/steam at high pressure from reservoirs in the earths crust, which can be utilized for e.g. electricity production. The project aims at investigating particle generation from dissolved minerals (SiO2 particles from dissolved H4SiO4) when temperature and pressure drops. In 2020/21the numerical models for SiO2-particle generation from superheated steam have been extended to also include agglomeration of already generated particles. The numerical model for deposition of (nano-)sized particles onto solid walls has been developed further and compares well with published data. Initial experiments of particle generation and deposition from superheated steam have been conducted and compared to model predictions, however, with limited success. This is attributed to stability problems with the experimental setup. Further experiments are planned in 2022 with a modified experimental setup.

High pressure and high temperature hydrothermal geothermal resources represent a large energy source that can be utilized for e.g. power production both onshore and offshore, benefiting from Norway's leading competence in drilling and subsea oil/gas production. Due to high pressure and high temperature, the water chemistry may contain significant amounts of dissolved minerals which may precipitate during cooling/pressure relief and deteriorate or damage vital components in the power production system. The major goal of the project is to provide knowledge and predictive methods for the precipitation behavior, and propose mitigation methods. This will in turn enable the design of robust power production systems. Different power production systems, based on direct use of the well fluid or indirect use by heat exchange will be analyzed with respect to feasibility and efficiency. Major project activities are: - Modeling of the well fluid properties as function of pressure and temperature (significantly higher than today's conventional hydrothermal systems), particularly with respect to mineral and gas solubility, - Experimental validation of vital fluid properties, - Feasibility analysis of power production systems having direct well fluid usage in the turbine or indirect usage through heat exchangers. Available information from the Iceland Deep Drilling Project will be used in the project. The outcome of the project will provide vital knowledge on the well fluid behavior in a power production system such as potential problems associated with mineral/salt precipitation, corrosive components, solidified particle erosion, which is required for the successful development of robust end efficient power production systems.

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ENERGIX-Stort program energi