Method for utilizing the inner energy of an aquifer fluid in a geothermal plant

A geothermal plant for using the inner energy of thermal water mixed with dissolved gas from an aquifer in a closed circuit comprising

• at least one withdrawal equipment for aquifer fluid in the area of a respective withdrawal borehole of more than one borehole,
• a gas separation device for separating the aquifer fluid into thermal water and gas,
• at least one device for using the thermal energy comprising at least one first heat exchanger, for using the thermal energy comprised in the thermal water for heating circulated heating medium and/or at least one equipment for using thermal energy for electricity generation comprising a ORC-power plant, and/or for operating a desalination plant,
• a combustion device for separated gas that is a gas engine, with at least one thereto coupled generator for generating electricity, the combustion device producing a flue gas,
• at least one device for using the thermal energy in a stream of the flue gas,
• an amine scrubber with a downstream positioned device for decomposing ammonium carbonate by-product produced by the amine scrubber into amine and CO2, the ammonium carbonate heated with heating medium that has been heated with flue gas for separating the CO2, said amine scrubber being arranged in the stream of flue gas downstream of the at least one device for using its thermal energy,
• a supply/feed line for the CO2 obtained after gas scrubbing into either a compressor and then via a mixing device, into a recirculation line for the thermal water leaving the at least one first heat exchanger or an ORC-power plant or a desalination plant, or such supply/feed line into a compressor for bringing the CO2 into the supercritical state and then into a supply/feed line for scCO2 that is separate from a supply/feed line for thermal water and which both lead into the aquifer,
• at least one recirculation equipment for reinjecting the carbon dioxide and the cooled thermal water into the aquifer through more than one reinjection boreholes distant from the more than one withdrawal boreholes in order to minimally disturb the aquifer,
• mixing device upstream of the at least one combustion device for mixing the gas with combustion air, and
• a flue gas treatment device, downstream of the combustion device,
• wherein the at least one recirculation equipment is configured to either:
• separately recirculate CO2 compressed to supercritical state (scCO2) and cooled thermal water into the aquifer down to a depth where the pressure in the aquifer is such that the CO2 remains in supercritical state, dissolve the CO2 into the simultaneously reinjected cooled thermal water, and the feed the solution deeper into the aquifer, or
• feed compressed CO2 into the cooled thermal water by a trickling scrubber, and then reinject the thermal water mixed with CO2 into the aquifer,
• wherein the recirculation equipment is configured to reinject the CO2 and cooled thermal water into the aquifer at a depth of 2000 to 2500 m for final sequestration.

A method for using the inner energy of an aquifer fluid comprising geothermic thermal water mixed with dissolved gas and crude oil in a closed circuit, wherein the method comprises the steps

• producing aquifer fluid from an aquifer by means of a withdrawal equipment via more than one withdrawal borehole,
• separating gas by degassing the aquifer fluid in a gas separation device resulting in degas sed thermal water,
• separating crude oil resulting in degassed and oil-free thermal water,
• using the heat energy of the degassed thermal water in at least one device/equipment for using thermal energy comprising at least one first heat exchanger, as well as
• performing at least one combustion process with the separated gas and the separated crude oil in at least one combustion device, that is a gas engine or a diesel engine, and using the inner energy of the gas and crude oil by operating at least one generator, wherein a flue gas is produced by said at least one combustion device,
• removing undesired substances from the flue gas by means of a first flue gas purification device comprising an amine scrubber with a downstream positioned device for decomposing ammonium carbonate by-product produced by the first flue gas purification device into amine and CO2 by heating the ammonium carbonate with heating medium that has been heated with the flue gas and recirculating the amine into the amine scrubber, and
• reinjecting the CO2 and the cooled thermal water into the aquifer through more than one reinjection borehole distant from the more than one withdrawal boreholes in order to minimally disturb the aquifer,
• wherein a mixing device for mixing gas and crude oil with combustion air is positioned upstream of the at least one combustion device, and wherein the mixing ratio is regulated by means of a lambda sensor positioned in a stream of the flue gas,
• wherein the crude oil-air-mixture or the crude oil-gas-mixture prior to being fed into the at least one combustion device is pre-heated in a second heat exchanger, and
• wherein flue gas purification is performed in a second flue gas purification device comprising a catalyst, downstream of the at least one combustion device, and
• wherein reinjection of the CO2 and the cooled thermal water is performed either:
• by compressing the CO2 to the supercritical state prior to reinjection and wherein the reinjection of the scCO2 and the cooled thermal water into the aquifer is performed separately down to a depth where the pressure in the aquifer is such that the CO2 remains in supercritical state, dissolving the CO2 into the simultaneously reinjected cooled thermal water and feeding the solution deeper into the aquifer, or
• by compressing the CO2 and then feeding the CO2 into the cooled thermal water by a trickling scrubber, followed by reinjection of the thermal water mixed with CO2 into the aquifer, and
• wherein reinjection into the aquifer is at a depth of 2000 to 2500 m for final sequestration.