Electrostatic precipitators are more economical than other dust removal systems.
Operating costs are reduced due to low energy consumption, reduced spare parts costs and minimal maintenance requirements. Optimum availability of the GrIIn electrostatic precipitator is assured, which is as good or better as that of upstream equipment such as kilns, boilers and mills.
The typical applications for electrostatic precipitators are:
• Production plants for cement and limestone
• Coal- and oil-fired boilers
• Biomass fired boilers
• Refuse and sludge incinerators
• Gas production plants
• Production plants for iron and steel
• Production plants in the electro-metallurgical, chemical and cellulose industry
Method of operation
The electrostatic precipitator is suitable for the separation of solid particles from gas.
Electrons are emitted from discharge electrodes which have been charged with a rectified negative high voltage. These electrons migrate to the collecting electrodes and meet thereby gas molecules and dust particles. As the electrons accumulate on the dust particles, the latter become negatively charged; the electric field transports them to the earthed collecting electrodes where they remain.
In the GrIIn horizontal electrostatic precipitator, the collecting electrodes consist of profiled plates. These form a system of passages through which the exhaust gases flow. The robust and unbreakable discharge electrodes - type RS - are arranged along the central axis of the 400 mm wide passages. Mechanical rapping equipment cleans the collecting as well as the discharge electrodes by means of periodic rapping.
Sizing
The velocity component at which the particles move in the gas stream towards the collecting electrodes is known as the migration velocity. It is a theoretical value only but it is a very important empirical factor for sizing. With the formula developed by W. Deutsch in 1922, the dust removal efficiency can be calculated.
Important parameters, which determine the migrationvelocity, are:
• Electrical resistivity of the dust
• Dust content at the precipitator inlet
• Dust content at the precipitator outlet
• Granulometry
• Chemical composition of the dust
• Gas analysis
• Gas temperature