Geological characteristics ask for smart pumps that offer flexibility in the construction to suit their place of action. In shallow wells with less than -650m water level, the line shaft vertical pump configuration is preferably used. It's major advantages are the adaptability and simplified maintenance.
Sulzer SJT (Geo) are designed for geothermal production in shallow wells. The pump can be adapted to the optimum length to pump hot water at the needed output flow.
Binary cycle geothermal plant organic rankine or kalina cycle
Binary cycle processes are quite frequent nowadays to make use of the medium enthalpy hydrothermal resources available in the underground. A secondary working fluid having a flashing point at much lower temperature is heated-up by the hydrothermal resource and then expanded in a thermal turbine to drive an electric generator.
A binary cycle plant transfers heat from the hot geothermal fluid (105°C < T < 185°C) that is sent through a heat exchanger to vaporize a secondary working fluid such as pentane, iso-butane in the Organic Rankine Cycle, or ammonia in the Kalina Cycle. The working fluid is then expanded in a turbine, condensed and reheated in a closed loop cycle. The brine is disposed of by re-injection into the ground. Sulzer supports these processes with Production pumps (PP), Brine Re-Injection pumps (BRIP), Hydrocarbon Feed pumps (HFP), Cooling Water pumps (CWP) and auxiliary pumps.
Dry rock enhanced geothermal systems are currently being deeply investigated. In such cases, the hydrothermal resources are not available in the underground but generated artificially through the stimulation of fractured hot bedrock by injecting water on them. The outcome of this technology is usually very high enthalpy hydrothermal resources.
Dry rock Enhanced Geothermal Systems (EGS) have an injection well (deeper than the ground water tables) drilled into hot bedrock that has limited permeability and fluid content. Water is injected at very high pressure usually by reciprocating pumps, to ensure fracturing and re-opening of existing fractures some distance from the injection wellbore. The production well, which intersects the stimulated fracture network, has water circulated to extract the heat from the hot rock. The temperature of the water extraction can be higher than in the natural geothermal fields, resulting in higher vaporization pressures and thermodynamic efficiencies. Depending on the production hot water temperature (T < 280 ºC), the EGS fields can be typically combined with binary cycle or flash steam power plants. Sulzer supports these processes with high pressure Brine Re-Injection pumps (BRIP), Condensate Re-Injection pumps (CRIP), Hydrocarbon Feed Pumps (HFP), Cooling Water pumps (CWP) and auxiliary pumps.
Dry steam geothermal resources were the first used since the beginning of the 20th century to generate electricity. In this process, the steam source available in the underground flows naturally to run a thermal turbine driving an electric generator.
A dry steam plant has production wells that are drilled down to the geothermal reservoir. The superheated pressurized steam (180°C < T < 280°C) is brought to the surface at high speeds and passed through a steam turbine to generate electricity. The steam passes through a condenser and is converted into water. The condensate is then re-injected into the ground through wells. Sulzer supports these processes with Condensate Re-Injection pumps (CRIP), Cooling Water pumps (CWP) and auxiliary pumps.
Flash / binary geothermal power plants are also described as combined-cycle. The purpose is to optimize the efficiency of the thermal cycle combining the high enthalpy hydrothermal resources available in the underground by flashing them into steam while the rejected hot brine is used to flash a hydrocarbon or ammonia in a binary cycle.
A flash/binary cycle plant uses a combination of flash and binary technology. The portion of the geothermal fluid (185 ºC < T < 220 ºC) which "flashes" to steam under reduced pressure is first converted to electricity with a backpressure steam turbine. The low-pressure steam exiting the backpressure turbine is condensed in a binary system. Sulzer supports these processes with Production pumps (PP), Brine Re-Injection pumps (BRIP), Hydrocarbon Feed Pumps (HFP), Cooling Water pumps (CWP) and auxiliary pumps.
Flash steam plants use high enthalpy hydrothermal resources available in the underground that are flashed into steam in a drum at low pressure. The flashed steam runs a thermal turbine driving an electric generator.
In a flash steam plant, hot and high-pressure water (185°C < T < 220°C) is converted into steam by flashing the extracted liquid through reducing the pressure. The liquid is separated into steam and brine. This brine is pumped back down into the reservoir again and the steam is sent to the turbine, which drives a generator. After passing through the turbine, the steam enters a condenser and is cooled to a liquid state, then pumped back down into the reservoir. Sulzer supports these processes with Production pumps (PP), Brine Re-Injection pumps (BRIP), Condensate Re-Injection pumps (CRIP), Cooling Water pumps (CWP) and auxiliary pumps.
