Siemens Electrostatic Precipitator Reduces Emissions
Sept 17, 2009 – A mobile test installation for electrostatic precipitators is helping to reduce the emissions of coal-fired power plants. Plant operators can use it to monitor and optimize the performance of flue gas filters. This is possible because electrostatic precipitators, filters which remove tons of dust from flue gas daily, work up to 30% more efficiently when retrofitted with modern power electronics. Until now, exploring the potential for optimization required replacement of the power plant’s electronics. Now there is the mobile testing unit from Siemens, which requires far less expense and work and quickly provides the plant operators with a basis for decisions concerning modernization. Every day up to 10 tons of dust can accumulate in a coal-fired power plant. Electrostatic precipitators, which can be as big as an apartment house, make the flue gas dust-free. The precipitators use high voltage to produce ions, which collect on the dust particles. The charged dust accumulates on the filter’s precipitation electrodes, large plates from which the accumulations are knocked off at specific intervals. The filters remove more than 99.9% of the dust from the flue gas. The higher the applied voltage and the more ions that are produced in the gas, the more efficiently the filters work. Flue gas filters are part of the Siemens environmental portfolio, with which the company generated €19 billion in sales in 2008. One challenging aspect is the electronic control system of the process. The high voltage from the supply voltage is transformed and rectified to up to 120 kilovolts. Modern power transistors in the voltage converter systems supply a smoother direct current with high output. They effectively bring more energy into the filter and produce more ions in the gas. What’s more, the new control systems are less sluggish and can be restarted more quickly following a dielectric breakdown. Such cases are not unusual, because the high voltage is run almost to the breakdown point. The new components enable the filters to deliver better performance or the same results with less energy consumption.
Plant operators used to have to replace their facility’s components in order to determine if it would pay off to upgrade the plant’s electronic systems. This caused interruptions of operation over a period of several days and resulted in high costs. In just a few days, the mobile installation from Siemens Industry provides the information needed to decide if a new electronics system alone is sufficient to optimize the filter or if more extensive changes to the plant are needed.