Industrial CO2 emissions. Geological storage of CO2 is a new and key technology to fight global warming (2005). © BRGM - Dominique Quiniou

CO2-DISSOLVED : storing industrial CO2 emissions while producing geothermal energy for local use

03.24.2014
Associate the capture of CO2 in industrial smoke and flue gases, its local storage dissolved in the brine of a deep saline aquifer, and the recovery of geothermal energy: A new approach proposed by the CO2-DISSOLVED Project for further valuation of the "CO2 capture and storage" concept.

CO2-DISSOLVED project logo

The CO2-DISSOLVED Project (CO2 Dependable Injection and Storage System Optimized for Local Valorization of the geothermal Energy Delivered) aims to store industrial CO2 emissions while producing clean and renewable energy for local use.

This project is funded by the ANR (French National Research Agency) in the framework of the 2012 SEED call for proposals (Energy Efficient and Decarbonized Systems).

An innovating, different, though complementary approach to a "classic" sector.

Projects for the geological storage of CO2 generally plan for its injection under supercritical conditions, i.e. in a state between gas and liquid, thus maximizing the stored quantities that can involve several million tons per year. When no site is available for the secure and durable storage of CO2 near a major industrial producer, it must be transported to its injection site, entailing very high induced costs.

The CO2-DISSOLVED Project studies a different option that consists in injecting CO2 dissolved in brine, close to the emitting source. The infrastructure for this (see the figure) is based on a set consisting of a production well and an injection well, which allows pumping the brine from the reservoir and then re-injecting it after having been saturated in dissolved CO2. With this process, it will be possible to overcome the inherent problems of the "classic" approach, such as the pressure increase and migration of the initially present brine, or the risk that CO2 will migrate into overlying geological formations in the absence of a light gaseous or supercritical phase. In addition, it is planned to recover the heat in the brine pumped by the production well for local use by the industrial CO2 emitter and/or for feeding a heating network.

The major drawback of this approach lies in the quantity of CO2 that can be injected, which is physically limited by the solubility of CO2 in the brine. However, injection rates of around 100,000 tons of CO2 per year are a realistic target. The CO2-DISSOLVED Project will thus study the technical and economic feasibility of using this technology in the immediate vicinity of low to medium industrial emitters (10,000-150,000 tons of CO2 per year).

Modelling and experimentation for understanding and quantifying the induced phenomena

Even though the project basically is a feasibility study using engineering methods, such as dimensioning calculations and numerical simulations, ambitious research work will be necessary as well:

  • The usual methods for site monitoring and risk assessment must be reviewed in the light of new constraints inherent in this original approach proposed for the CO2-DISSOLVED Project. Innovating solutions for geochemical and geophysical monitoring will be evaluated and tested, both in the field and in the laboratory. A new methodology for risk analysis will be specifically designed and applied, in accordance with the modelled and observed properties of the system as a whole, i.e. capture, injection, CO2 storage and heat recovery.
  • The brine acidified by dissolved CO2 will be chemically reactive with the mineral phases of the aquifer as soon as it exits the injection well, contrary to the "classic" approach where the reactive acid front follows the extension of the supercritical CO2 "bubble". Specific work will focus on the "near-well" area, based on new experimental and modelling approaches. An experimental laboratory installation will thus be specifically designed and used for this project.
  • Earlier economic models of the CO2 will be rendered obsolete by the local application of an associated capture-storage and geothermal-heat-production technology to small CO2 emitters. This will require the development and validation of new economic models that will then be applied to two test cases in France and Germany.

Perspectives

The expected results will provide us with a range of innovating technologies associated with new experimental and theoretical tools. These will include: a device for capturing and dissolving CO2; monitoring tools; an experimental laboratory "miniature well"; coupled models for simulating flow, mass and heat transport and geochemistry; and an economic model. Promising industrial applications can be envisaged as soon as the project will be finished after 36 months, provided that the conclusions on the feasibility of the concept of CO2 injection coupled with geothermal-heat recovery are positive.

TO FIND OUT MORE

Visit the CO2-DISSOLVED Project website

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