Oil and gas wells are capable of producing electricity through a binary cycle as long as the wells can produce hydrocarbon or water above 180⁰ C (82⁰F). This electricity, applied either directly or indirectly to offsetting the well site’s auxiliary electricity requirements, decreases net operating costs, extends the life of the well and in some cases is eligible for renewable energy credits. Based on the scientific temperature mapping of the continental United States conducted by the Department of Energy (DOE), the National Renewable Energy Laboratory (NREL) and Southern Methodist (SMU) Geothermal Laboratory, fluid temperatures between 180⁰F to 450⁰F can be found in areas where oil and gas production is concentrated at average well depths of 10,000 to 20,000ft. Existing, coproducing oil and gas wells offer immediate access to geothermal energy through the brine extraction process. The integration of Thermapower® Organic Rankine Cycle (ORC) Systems into these wells is a fast an effective solution for accessing and capitalizing on sub-surface heat energy.
The cooling processes of gas compression at well sites, gathering facilities, gas processing plants and pipeline compressor stations present another opportunity to utilize waste heat. Compressed natural gas has to be cooled in order to push a higher volume of gas through the pipeline. Current solutions include using air coolers before the injection in a pipe or water-to-air coolers from reciprocating compressors. In both solutions, electricity is used to run the cooling fans pumps motors, increasing operating costs and decreasing process efficiency. Thermapower ORC Systems can improve operating costs, since less cooling equipment is required and the electricity produced can be used onsite.
In addition, excess heat produced by the amine gas sweetening process at gas processing plants can be recovered and utilized. Lean amine fluid removes carbon dioxide and hydrogen sulfide from natural gas through absorption and chemical reaction. Once the amine fluid absorbs the acidic gases, it becomes “rich” amine. The rich amine is then heated to remove the acidic gases, regenerating the amine. The regenerated “lean” amine must be cooled in order to be reused and to continue the cycle. To cool the lean amine, electricity is used to run the cooling equipment, increasing operating costs and decreasing process efficiency. Thermapower ORC Systems can improve operating costs, since less cooling equipment is required and the electricity produced can be used onsite.
Another oil and gas process that can benefit from the use of ORC technology is natural gas flaring. It is better for the environment to completely burn the gas at high temperatures using incinerators to significantly reduce emissions. Thermapower ORC Systems can capture heat from flared gas at well sites, plants and refineries and turn it into electricity for use onsite or to be sold to the local utility.