Research On Ouantitative Analysis Of Coal Pvrolysis Products Using TG-FTIR-MS Technique

Researches on gaseous and particulate products from coal combustion are important for knowing coal formation, combustion mechanism and coal clean utilization. Qualitative and quantitative measurement on products from coal pyrolysis were investigated using thermogravimetry-Fourier transform infrared spectroscopy-quadrupole mass spectrometry (TG-FTIR-MS). The research results can provide scientific basis for studying combustion mechanism and pollutants emission controlling.Firstly, the effects of carrier gas flow, TG furnace temperature, detecting resolution and scans on FTIR absorbance spectra of CO2 were discussed using pulse thermal analysis (PulseTA) technique. The results showed that the ability of gas diffusion and convection were influenced by carrier gas flow and TG furnace temperature. The spectrum structure and data acquisition time were influenced by resolution and scans. The FTIR calibrating signals are mainly affected by carrier gas flow and resolution.Secondly, calibrating curves of CO2 and CH4 were made for FTIR and MS by PulseTA technique. The varying degree of interference among gaseous components during coal pyrolysis on the signals of FTIR and MS may lead to difference in the quantitative results. The yields of CO2, CH4 during Shenhua blended coal pyrolysis were 65.9μg·mg-1,24.1 μg·mg-1. And the calibrating curves of CO and H2O were made by solid decomposition. The yields of CO and H2O were 98.7μg·mg-1 and 52.5μg·mg-1, respectively.Thirdly, the gases including H2、H2O、NH3、CO2、CO、CH4 and some compounds containing C-O and C-H groups evolved during TCNY coal pyrolysis were detected by TG-FTIR-MS. The effects of coal rank, atmosphere, particle size and heating rate on the quantitative release behaviors of CO2、CH4、CO and H2O were discussed. The way to choose right mass to charge ratios to detect hydrocarbon fragments was also discussed, and the semi-quantitative release behaviors of hydrocarbon fragments and the gas products containing C-H during coal pyrolysis were analyzed. The results showed that the effects of coal rank, atmosphere, particle size and heating rate on release behaviors of different gaseous products were not the consistent during coal pyrolysis.Finally, the evolution profiles of the sulfur-containing compounds detected by FTIR and MS during high sulfur coal pyrolysis were compared. Real-time profiles of H2S, SO2 were corrected by deducting the interference of H2O, and COS was corrected by deducting CO respectively to obtain accurate evolution profiles. The effects of heating rate and oxygen concentration on evolution behaviors of sulfur-containing compounds were analyzed. Combined with Rayleigh theory, the volume concentration of carbon particles during coal pyrolysis was 0-60ppb estimated using extinction method.