Determination and chemical characterization of the nanoparticles emitted from the cement kilns
Finanziato: Buzzi Unicem S.p.A.
Periodo: Settembre 2016 – Luglio 2020
In order to control and reduce the emission of particulates from industrial plants, it is necessary to know the relative and absolute contribution of the various emission sources. For this purpose, one of the possible techniques consists in evaluating, directly at the emission, the dimensional distribution of the particles, the concentration of the various fractions, both in terms of mass and in terms of size, and their chemical composition.
As part of this project, based on the experience gained during the previous activity carried out at the Buzzi Unicem SpA plants, it is expected to develop a sampling system consisting of a probe capable of directly transferring the sample from the emission to a multistage impactor; the samples thus collected, segregated dimensionally, will then be analyzed off-line in the laboratory with different techniques and instruments, capable of characterizing the chemical composition of the inorganic fraction of ultrafine particles and nanoparticles. The same characterization analyzes of the particulate will be carried out in the ambient air surrounding the plants in question, in order to evaluate the possible correlation between the particulate present in the environment and the emission of the cement plant. In a future further phase of the work, once the method of sampling has been optimized, the experimentation will be extended, in the same measurement sites, to the analysis of the organic fraction of the particulates.
The Institute has numerous equipment that allows the collection and analysis of dimensionally segregated particulates:
– multistage sampling system of atmospheric particulate NanoMoudi 125-R) with 13 rotating impact plates
– multistage sampling system for atmospheric particulate matter Moudi II (120-R) with 10 rotating impact plates
– Scanning Mobility Particle Sizers (SMPS, TSI 3936)
– Aerosol Mass Spectrometry (HR-TOF-AMS)
The objective concerns the concentration in mass and the chemical composition, the ultrafine particulates and the nanoparticles, due to their small size and their negligible contribution to the total mass of the emission, cannot be characterized with the instrumentation and methods normally used for the analysis of atmospheric dust in ambient air. The mass of emission material attributable to these dimensional fractions is in fact normally negligible, with levels generally lower than the detection limits of the sampling and analysis protocols available for environmental atmospheric particulates. The chosen approach for this type of measurement is therefore represented by the combined use of specific devices for sampling and in-situ measurements and particularly sensitive methods for off-line analysis of the samples, capable of carrying out the characterization of the various dimensional fractions from a chemical, morphological and microanalytical point of view.
- Università Sapienza