The report presents some results of experiments which were undertaken with the aim of determining reaction rate data in turbulent diffusion flames of industrial size, burning fuel oil and gas. After a description of the burner systems used, the choice of input parameters which would allow for the evaluation of reaction rate data from locally measured flame properties, is discussed. The change of carbon distribution along the flame axis, as a function of input conditions, is demonstrated, and an effective activation energy for soot formation in propane flame is derived.