Electrostatic precipitator diagnostics based on flashover characteristics

Performance monitoring on large industrial precipitators is today´s practice. Usually, the stack opacity is measured and recorded on a computer system. The performance is indicated through the precipitator efficiency, which is defined as the relation between input dust content N₀ and output dust content N: η=N₀-N/N₀. The precipitator efficiency η is monitored not exactly due to the missing measurement of the precipitator inlet particle load of the gas. However, achieving the permitted emissions for the entire process indicates sufficient performance. Exceeding these permitted values leads to concerns about the precipitator performance. Identifying the reasons for decreasing performance can be difficult due to the high number of parameters in a precipitator system. To locate the problem either in the electrical, mechanical or the operational parts of the system, the electrical data and particularly the flashover behavior of the individual high voltage fields can be investigated. Using the data recording and display features of modern controls comprehensive precipitator diagnostics can be done and performance can be optimized based on the current system state. Possible fault conditions like dust build ups, damaged spray wires, misaligned collecting plates or faulty insulators can be distinguished by the spark voltage, frequency and required deionisation period. Additionally, performance drops caused by insufficient electrical supply and control can be detected and corrected automatically in many cases.