Equipped With Demister Our Steam Boilers Reach The Highest Steam Quality And Purity Available On The Market
Thanks to the presence of an electrically insulated neutral point, Elpanneteknik’s electrode steam boilers can connect directly to the common electrical grid without using a dedicated grounded transformer. The neutral point (the inner vessel) has a high resistance to earth, minimizing earth-fault currents to approximately 5 amperes in the case of a short circuit between phase and neutral.
Demineralized and deaerated water is pumped from the feedwater tank into the outer vessel to maintain constant overall water volume.
The circulation pump transfers the water from the outer vessel to the inner vessel. For redundancy, two pumps can be installed. If the pump in operation fails, the other pump starts automatically. Water level in the electrically insulated inner vessel is regulated by the amount of water pumped in and the inner vessel control valve that allows water to drain out into the outer vessel.
Power and steam output
Power and steam output is determined by the water level in the inner vessel in contact with the electrodes and the conductivity of the water. Power can be regulated from 0% to 100%.
Automatic surface blowdown maintains the appropriate conductivity in the boiler water. The expected efficiency loss, with ammonia and trisodium phosphate dosing, is less than 0.1%.
All electrode boilers are high in efficiency due to the principle of using water as a resistor. So whether it’s immersion or jet type boilers, overall efficiency (including blowdown and insulation losses) is approximately 99%. High voltage electrical boilers are always electrode boilers.
Elpanneteknik Sweden AB has the market’s widest product line, ranging from 1 MW to 80MW, from 6kV to 20kV. Elpanneteknik immersion boilers are simple in concept and operation and don’t have the complicated nozzle arrangements found in jet/spray-type designed boilers, which wear out and require frequent adjustments for optimal functionality. Equipped with a demister, Elpanneteknik Boilers offer the highest levels of efficiency on the market.
The electrode boiler has an inner vessel mounted on ceramic insulators inside the shell (outer vessel). The three phase electrodes, each consisting of a number of bars mounted on a single electrode plate, are located in the inner vessel. Each electrode is suspended in insulated bushings (hollow ceramic insulators) at the top of the boiler.
The inner vessel, which also forms the neutral point of the electrical system, divides the boiler into two water chambers (inner and outer).
Electric power is converted directly into heat as the current flows through the water. The current passing through the water is a function of the active surface area of the electrodes and the boiler water’s conductivity. The current is controlled by regulating the water level, thus varying the active electrode area.
The level is raised by closing the valve in the bottom of the inner vessel and at the same time opening the valve in the circulation pipe. The level is lowered by doing the opposite.
As long as the load does not exceed the power setpoint (max. allowed power), it is the boiler’s steam pressure that is controlled.
The water volume in the boiler is kept constant at set level by regulating the control valve on the boiler’s feedwater inlet pipe. The volume is calculated from the levels of both the inner and outer (boiler) vessel.
The water is circulated from the outer vessel (boiler vessel) to the inner vessel by a circulation pump.
In low voltage electrical steam and hot water boilers, an electronic step controller programmed to fit the boiler size regulates power and boiler temperature. Electrodes are replaced by electrical elements.
All Elpanneteknik boilers are supplied with an option to connect an external signal for temperature set-point and step limitation. Furthermore, a PLC with touch-screen makes it easy to use for non-technical staff.
Key safety functions can be operated separately from the PLC to ensure redundancy. Elpanneteknik Sweden AB have long and well-proven experience delivering containerized solutions.