Sampling device for PCDD/F sampling in high temperature raw gases

Introduction

Within the work for the Research Project “Thermal processes with energy recovery for sludge and special wastes disposal” carried out with the Water Research Institute, our group studied the conditions that can favour the PCDD/F formation during the incineration steps, expecially in the high temperature sections as the afterburning chamber and the heat exchanger, where reformation reaction are documented [1,2]

The sampling of PCDD/F can be affected by many errors, but they can increase dramatically during the sampling of raw gases before the abatement devices, where the temperature and the concentration of other pollutants is very high. It is widely recognised that after particulate abatement PCDD/Fs are distributed between vapour phase and fine particles [3], but before abatement the distribution is hardly affected by temperature and by particles dimensions. For this reason the PCDD/F sampling need isokinetic conditions, otherwise it can be not representative of the real distribution. Moreover, a temperature-controlled procedure is needed, in order to avoid PCDD/F De Novo sinthesis along the sampling train due to the cooling of sampled gases. For this kind of problems a device for high temperature sampling of organic micropollutant was developed.