GDD is a new smart combination between Carbon Capture & Storage , Geothermal Energy and Industrial Waste Heat to replace the original geo-brine of saline aquifers by CO2/GHG/flue gas/ liquid wastes at the nearest suitable location to the pollution source site.
Introduction Carbon Capture and Storage (CCS)
CCS technology means capturing and storing CO2 within an underground permeable layers in order to keep CO2 permanently isolated away from atmosphere to prevent global warming disaster .
The domain mechanism of trapping CO2 is the structural physical trapping mechanism in addition to other minor trapping mechanisms including residual trapping , solubility trapping and mineral trapping mechanism.
Some of CCS projects are storing CO2 at shallow underground aquifers with depth range of 500-1000 m beneath earth surface. While the majority of modern CCS projects are based on utilizing depleted oil and gas fields to store CO2 for enhancing oil production (Known as CO2-EOR Process) in order to get benefit from the costly CCS technology.
Defect of CO2 storage at depleted oil and gas fields
Although CO2 storage at depleted oil and gas fields is a good option to utilize CO2 in enhancing oil production and to reduce some CCS cost, But CCS storage at depleted oil and gas fields is not suitable for the majority of industrial/ power production facilities due to the following reasons :-
1- The scarcity and the limited geographic distribution of the majority of oil and gas fields around the world
2-The far distances at many places between urban areas, power plants and heavy industries sites to oil and gas fields .which requires large and expensive onshore/offshore pipe line’s and infra structures
3-Limited storage volume capacity as the original hydrocarbons at all depleted oil and gas fields already replaced by water injection while first production phase by water flooding and the formations pressures had been maintained constantly near to virgin pressure during production phase till the hydrocarbon been depleted
4-Storage at depleted oil and gas fields requires over pressurizing host rock while CO2 injection to increase storage volume capacity which can induce seismicity and rock fracking.
5-Additional cost is required to check the integrity of nearby abandoned and operating wells that penetrating the same storage layers (including replacing eroded casings and performing remedial cement jobs) to avoid leakage risk through old wells.
New in GDD system
The working principal of GDD system is based on replacing the original geo-brine of deep saline aquifers at the nearest suitable locations to polluters sites by CO2/GHG/Flue gas /Liquid wastes while utilizing the produced geo-brine simultaneously at surface for generating clean electivity, desalinating water, extract Lithium/minerals/salts and producing green hydrogen.
As deep saline aquifers are widely abundant (much more than oil and gas fields) at around 90% of urban areas around the world as multi layers in sedimentary rocks at different depths from ± 1 Km down to +10 Km within earth crust. And fortunately the fast majority of them have an appropriate permeability, porosity and multi-sealing elements similar to oil and gas reservoirs to be used successfully to trap and store CO2/GHG/Liquid wastes safely .
In addition to that, large brine aquifers have many valuable content of such as:-
- Thermal energy content from earth’s hot core (the fast majority of large brine aquifers have low to medium geothermal potential while a very few brine aquifers in some areas have high geothermal potential with temperature range of 150C up to 400C).
- High concentration of rare minerals such as Lithium and Bromine.
Concentrated salts from 50,000 up to 280,000 ppm.
- Dissolved methane gas from ancient organisms decays & activities (from 20 to +100 cubic feet of methane in one barrel of Geo-Brine).
- High hydraulic flow energy potential (Geo-pressure energy).
Advantages of Green Geological Disposal System (GGD)
- GGD is suitable for utilizing the widely abundant low geothermal potential saline aquifers.
- GGD has two new cheap Carbon capture technology associated with cheap/large scale energy storage application
- Greater storage volume capacity within host layer more than depleted oil and gas reservoirs.
- No risk of inducing any seismicity or fracking rocks due to over pressurizing host layer. rather than all existing CCS technologies.
- GGD has many revenue streams from original Geo-brine flow products to compensate the high cost of CCS (including extracted Lithium from Geo-brine. Hydrogen Fuel Production, 24/7 clean electricity production, Distilled water production, Salts Production ,Dissolved methane gas extraction and Works also as a large scale energy storage battery).
- Saving the cost and infrastructures of transporting CO2/GHG from polluters sites to the far oil and gas fields locations.
- Less energy consumption for injection process than depleted oil and gas reservoirs.
- Storing GHG permanently in a solid form (carbonate form) through the novel In-situ CO2 Lithification process within host rocks pore-spaces and fractures as an ultra safe method for storing CO2/GHG.
CO2 Geo-storage Comparison
GGD main components
- Flue gas/Geo-brine Heat Exchanger to add extra heat to the produced Geo-brine flow from the very hot combustion fumes.
- Disposal well for disposing the stored combustion gases, waste liquids and Geo-Brine residuals
Geothermal Producer well for producing Geo-brine from the same disposal layer.
- Geothermal / Geopressure energy converter unit ( such as flush or binary system with or without hydropower turbine) to extract energy from Geo-brine flow to use it to power the system’s port assembly ( Electrolysis unit, injection pumps and compressors)
- Reverse Osmosis unit or Vacuum desalination according to well’s head temperature, pressure and Geo-brine salinity
- Electrolysis unit to produce green hydrogen from the high salinity desalination residual brine/
- Mineral/salts extracting unit to extract valuable minerals and salts (such as Lithium salts, Bromine and rare elements) .
- Degasser unit to extract dissolved gases from water.
System Working Steps
I. Filling Phase ·
- The very hot combustion flue gas fumes (which are mainly N2, O2 / CO2/ water vapor/NOx/SOx) will be directed to pass through the Flue gas /Geo-brine Heat Exchanger to add extra heat to the produced Geo-brine .
- The flue gas can be compressed and injected directly without separating CO2 into disposal well after desulphurization and ashes removal ·Or CO2 can captured by any method from flue gas and injected separately into the disposal well.
- Liquid wastes will be collected and discharged directly into the disposal well after solid particles removal ·Due to the injection process of liquid wastes and flue gas (or captured CO2).
- The original geo-brine of the disposal layer will be flushed towards the geothermal production well and flow naturally at surface to release the extra induced formation pressure to avoid over-pressurization , rock fracking and inducing seismicity which beneficially has a lot of valuable geothermal products .
- The produced Geo-brine from geothermal producers well will pass through the Flue gas/Geo-brine Heat Exchanger and will be extra heated up by the very hot flue gas temperature
- The extra heated Geo-brine flow will pass through Geothermal/Geopressure energy converter unit to extract energy to use it to power the other system facilities
- After that the Geo-brine flow will pass to a Reverse Osmosis unit or to a Vacuum distillation unit (based on WHT, WHP and Fm salinity) to separate fresh water.
- The Degasser unit will extract the associated dissolved gases.
- The extracted dissolved methane gas will be combusted internally to increase the temperature of Geo-brine flow or for any other issue while all other harmful gases will be re-injected at the disposal well.
- The concentrated geo-brine will pass to an electrolysis unit and Mineral extraction unit to produce Hydrogen & NaOH/KOH , HCL, Lithium and salts ·(in case of presence high percentage of H2S gas a scavenger treatment process will be added)
- After that all geo-brine residuals will be re-injected at the disposal well.