Geothermal energy can generate electricity, It can also heat homes and other buildings. The concept is very simple - steam or pressurized hot water above 150 ℃ is transported to the ground through pipelines to drive generators to generate electricity, and then cooled. The lower temperature water is piped to the central heating system and then returned to the underground for natural heating. Geothermal energy is different from solar energy or wind energy. One of its main advantages is stability and reliability. At present, the production capacity of geothermal energy is very limited, with a production capacity of only 16GW, and it is limited to shallow underground water sources, generally within 3km. The capital cost of geothermal power plants is often higher than other sustainable technologies, but the continuous operation of the system can prove value for money.
The outlet water temperature of the geothermal well is about 200 ℃, containing a small amount of chloride and hydrogen sulfide. The materials used in the system range from typical carbon steel casing alloy to various grades of stainless steel and even high nickel alloy. The key components using nickel-containing materials include turbine, condenser, heat exchanger, pump, and piping system. The stainless steel used includes 630 (s17400), 316L (s31603), various duplex alloys, 6% molybdenum alloy (s31254) and nickel alloy 625 (n06625). Among the alloy materials used in power generation equipment, the use amount of nickel is about 100t. In the right application environment, these materials can provide clean surfaces with good corrosion resistance, strength, and heat transfer, so as to achieve cost-effective services.
