Method of regulating the flue gas temperature and voltage supply in an electrostatic precipitator for a cement production plant

A method for regulating a flue gas temperature (T1) in a cement production plant and controlling an electrostatic precipitator in the cement production plant comprising a kiln, a flue gas conditioning device, a mill, and the electrostatic precipitator which includes a plurality of precipitator sections, the method comprising the steps of:

• passing a flue gas from the kiln through the conditioning device;
• conveying the flue gas from the conditioning device either via the mill or directly to the electrostatic precipitator;
• performing a measurement of the flue gas temperature before the electrostatic precipitator;
• and
• supplying water to the flue gas for cooling purposes in the conditioning device as a response to the temperature measurement if the flue gas temperature is too elevated,
• wherein the performing step and the supplying step is executed using a flue gas regulating system and a control system,
• wherein the flue gas regulating system comprises:
• i. a first system which regulates the amount of the supplied water in accordance with a temperature measurement between a gas exit of the conditioning device and a gas inlet of the electrostatic precipitator operating during the operation of the mill, and
• ii. a second system which regulates the amount of the supplied water by:
• measuring the flue gas temperature (T1) prior to its introduction into the conditioning device and measuring a flow (Vg) of the flue gas, and
• calculating the amount of water required for cooling the flue gas to a desired temperature on the basis of the measured T1 and Vg operating when the mill is not in operation, and
• iii. an automatic switch for alternating between the first system and the second system, and
• wherein the control system is provided for controlling the electrostatic precipitator when a temperature increase occurs in a transition period, a separate control of each precipitator section being carried out during the transition period, the controls performed in the transition period having different durations for the respective precipitator sections, the durations increasing in the flow direction of the flue gas.