Grounding resistance for control of static electricity ignition hazards

The flow of hydrocarbon product in pipes generates static electricity at density levels that may be sufficient to cause sparks and ignition when product is delivered to a tank. This paper describes the formulation of a method that can be used to control such electrostatic ignition hazards during tank filling operations. The grounding current for a grounded metallic tank being filled with charged liquid was found. The grounding current found was used to find the grounding resistance limit that ensures that dischargeable energy is always below the ignition level. The analysis presented in this paper was focused on cylindrical tanks; however, the method can be extended to any shape charged liquid container whose electric potential is known.

Research highlights
► Electrostatic ignition hazard in petroleum product storage tank was studied.
► Transient accumulation and dissipation of charge in such storage tank was studied.
► A new model for estimating grounding resistance for low ignition risk is presented.