Enhancing the range of future operation conditions by upgrading the HV power supply of electrostatic precipitators - A case study

摘要

The operation of electrostatic precipitators (ESP) is often negatively influenced due to new process conditions caused by a large number of different fuels and frequent load changes to compensate for fluctuating power supplied by renewables (wind, solar) to the power grid. This is, for instance, due to increased space charge problems, increased specific particulate resistance, reduced ESP breakdown voltage and unadapted electrode cleaning when the raw gas particulate concentration, the particle size distribution and chemical composition change frequently. According to stricter environmental regulations and to ensure the long lifetime of flue gas fans, the performance requirements of ESPs will increase. Increased ESP performance can be achieved conventionally by increasing the SCA (Specific Collecting Area) with the installation of additional new ESPs or adding fields which is in many cases not possible due to given space. Increasing the ESP field height is limited because of the limited length of the ESP and the particulates must finally reach the hopper. Other opportunities are installing newly designed electrode systems, separating of electrical fields, optimising the gas/particulate distribution, adaptation of coal mix to minimise critical collecting conditions or installing a gas conditioning system. Furthermore, considerable performance improvements can be achieved by upgrading the high voltage power supplies to SMPS, even with significantly lower costs compared to the mechanical upgrade. SMPS are increasingly used in nearly all types of ESP applications providing advantages in the operation compared to the conventional thyristor-controlled power supplies. The potential for increased ESP collecting efficiency with SMPS can be first checked by use of the existing equipment. In addition, an SMPS test installation can prove this performance increase under real, unsteady operating conditions. The SIEMENS mobile SMPS test unit has been installed at Ingolstadt and Scholven power plants in Germany. The test results are described in the present paper.