Monitoring of electrostatic fire and explosion hazards at the inlet to electrostatic precipitators

The paper deals with the continuous monitoring of electrostatic fire and explosion hazards that can occur at the inlet to electrostatic precipitators (ESPs) when highly charged dust particles are transported by a gas carrier that can be the mixtures of both incombustible and combustible flue gases. The risk of ignition and even explosion is especially high in the presence of an explosive mixture of oxygen and, e.g., hydrocarbons, carbon monoxide, etc. To avoid the danger of electrostatic discharges and their consequences for a whole installation including an electrostatic precipitator a method and a specially designed and built system should effectively enable the continuous monitoring of the hazards and should immediately manage any automatic control system or some other control elements. Some theoretical considerations concerning the method proposed, the physical quantities that must be measured, and the derivation of a novel dynamic safety criterion for assessing the risk of hazardous electrostatic discharges are presented. Finally, the author presents and discusses the possible practical application of the microprocessor-based measuring system verified experimentally in the past to the continuous monitoring of the hazards and to the management of an automatic control system to be put into operation. The paper presents a certain idea and proposal of the problem's solution based on the author's many years' experience in the field of pneumatic transport of dusts, powders and granular materials, of the electrostatic measurements of electric and mechanical quantities characteristic of the particulate transport, and of the risk and prevention of discharges of static electricity in transporting pipes and silos, vessels, etc. (C) 2014 Elsevier B.V. All rights reserved.