A tracer impulse method is designed and implemented for determination of the residence time distribution (RTD) of particles in a cold flow model of a dual circulating fluidized bed chemical looping pilot plant. Ferromagnetic particles are used as a tracer. The method based on inductance measurements previously proved its suitability and convenience for determination of the concentration of ferromagnetic particles and the bed porosity. The current paper presents an improved system for the determination of inductance, based on an impedance circuit bridge. Injection and detection systems were designed and optimized for an extremely small amount of tracer, about 0.05% by mass. The system is entirely described, variables relevant for the attainment of an appropriate measurement are analyzed, and the first results of RTD experimentally determined are presented. Signals of high quality were obtained and successfully fitted to a simple model. The system shows a great capacity regarding the response time, quality of the signal, and suitability of results.