Electrostatic separation process, uses calculated optimum combinations of current pulse frequency, height and length to regulate addition of conditioning agent to gas

摘要

For each of frequency-height-length combination for the current pulse a first time is determined for the end of the pulse, and a second time is determined for when the voltage between the emission and precipitation electrodes falls to a given level. The length of the interval between these two times is used to determine an optimum frequency-height-length combination, and the length of the time interval in this combination is used to regulate the supply of conditioning agent added to the gas. An electrostatic separation process for purifying a gas comprises applying a periodically varying high voltage between emission and precipitation electrodes using a pulsed dc current, and regulating the addition of conditioning agents to the gas upstream from the separator unit. The frequency, pulse height and/or pulse length for the dc current are varied in order to give a number of frequency-height-length combinations. For each of these combinations a first time is determined for the end of a delivered current pulse, and a second time is determined for when the voltage between the emission and precipitation electrodes falls to a given level. The length of the interval between these two times is calculated and then used to determine an optimum frequency-height-length combination. The supply of conditioning agent is dependent on the length of the time interval in the optimum combination.