Mechanical seal for thermoelectric plant

Customized solution for water feed pumps


Mechanical seal for thermoelectric plant Mechanical seal for thermoelectric plant - Fluiten

Into a thermoelectric plant, the fuel, coal, oil or natural gas, is burned in a boiler, to produce thermic energy. The generated  heat transforms the process water in superheated steam which moves the blades of the turbine to produce electricity. An alternator, connected with the turbine, generates electricity at medium voltage. The up transformers raise the voltage level and connect the plant to the high  voltage electricity grid. The warmed steam is discharged from the turbine to the condenser to become condensed water using special water cooler. The condensed water is transferred to the boiler using a water feed pump to restart a new cycle.

Hot water losses are dangerous for people in the machinery and also are the cause of the efficency loss of the machine and then the entire plant. The mechanical seal must prevent accidental leakeges, must reduce the power consumption and the costs of the managements. The mechanical seal must also accept the conditions  of the shaft rotation speed that can exceed 20m/sec, the temperature that normally oscillates between 160° and 200° C and the pressure in the stuffing box which is measured between 15 and 50 bar.
In water feed pumps the lubrication of the seal surfaces must be guaranteed from the process water which viscosity decreases drastically with increasing temperature. With the decrease of the viscosity, the water loses its lubricating capability therefore the friction increases and overheating causes early consumption.
In order to avoid the faces wear the liquid film between the two surfaces must remain at the correct temperature correctly cooled. 
Fluiten’s proposal used in these applications envisages:
• the use of the PLAN 23 of API 682, a pumping ring, suitably dimensioned, maintains the process water circulation from the stuffing box to an heat exchanger, so that the temperature of the water is brought below 80°C.
• The stationary seal can perform with high speed rotation. 
• Surfaces and gaskets’ materials are suitable to perform at each pressures and maximum temperatures possible in the pump at any process stage.
• The use of Fluigrid technology to ensure a stable meatus of liquid film also during temporary variation of pressure and temperature.
Fluigrid technology provides a ring realized with hard material, usually silicon carbide, on which a microcavity network is provided with a particular laser processing. 
The filing allows the slipping between the sealing surfaces in a condition of reduced friction therefore with less heating and wear. 
• The cartridge configuration, complete with flange and shaft sleeve specifically dimensioned, prevents the possibility of assembly errors on the machine and ensures that the installation conditions will remain the same decided in the project.