Investigation of Electric Wind in the Corona Charging Unit of a Novel Electrostatic Collector An. M. Bologa, H.-R. Paur, K. Woletz Forschungszentrum Karlsruhe GmbH, Institut für Technische Chemie, Postfach 3640, D-76021, Karlsruhe, Germany 5th Electrohydrodynamics International WorkshopPoitiers, France, August 30-31, 2004
Flue gas cleaning Separation process in the one stage ESP Separation process in the CAROLA collector Advantages of the CAROLA: • One operation electric field; • Low operation voltage; • Strong electric field and effective particle charging in the charging zone; • Module principle of design. Separation process in the two stage ESP
Charged particle collection Charged particle transport Particle charging Gas CAROLA collector
Test of the CAROLA collector for oil mist Particle number concentration and fractional collection efficiency, Q=520 m3/h, U=16,4 kV, I= 6,2 mA
Task of investigations The behaviour of the particles in the charging zone depends on: • physical properties of the gas and particles, • gas velocity, temperature, relative humidity • charging system geometry, • voltage and corona current, • electrohydrodynamic phenomena, • etc. In the present article an electric wind in the charging system of the CAROLA collectors is investigated.
Results of investigations Current-voltage characteristics of the ionization section, flow rate for Dn=0,05 m is up to 106 m3/h, for Dn=0,04 m is up to 68 m3/h and for Dn=0,03 m is up to 38m3/h
Electric wind and air velocities Maximum electric wind and air velocities in the measurement points, Dn=0,05 m and H=0,03 m
Influence of the distance H to electric wind velocity Maximum electric wind velocity for different distances H
Dependence of maximum electric wind velocity on the distance from the charging system, U=19,9 kV, I=0,36 mA
Influence of applied voltage on electric wind velocity Dn=0,03 m Dn=0,05 m Dependence of the maximum electric wind velocity and corona current on applied voltage, H=0,03 m Dn=0,04 m
Electric wind in the pilot charging unit (I) Schema of the measurement
Electric wind in the pilot charging unit (II) Dependence of the electric wind velocity and corona current on applied voltage in the pilot charging unit
Conclusions • The electric wind velocity in the charging system needles in the nozzles increases with increase of the applied voltage. • At distances H=Dn the electric wind velocity downstream the charging system is constant in the measurement points. • The electric wind can change air velocity in the centre part of the flow downstream the nozzles. • With increase of the distance from the charging unit the electric wind velocity decreases. • The electric wind does not influence on the charged particle transport in the CAROLA collector at the distances H=3Dn.