Biomass briquettes are an environmentally friendly fuel and have extensive utilization prospects. Compaction pressure is a crucial factor during the production of biomass briquettes, affecting its densification and subsequent potassium release behavior. The release of alkali metals during combustion is typically studied using offline analytical techniques. However, these methods fail to provide real-time measurement of alkali metals release during the combustion process. Therefore, FES, through its equipment simplicity, low operational cost, real-time measurement, and robust adaptability to industrial environments, is commonly employed. In this study, the effect of compaction pressure (80, 130, and 180 MPa) of camphor wood briquettes on potassium release in a premixed flame was investigated by means of Flame Emission Spectroscopy. A spectrometer was used to obtain flame spontaneous emission spectra at three heights above the burner. Based on the proposed spectral analysis method and a calibration procedure, time-resolved flame temperature and concentration of gas-phase potassium in camphor wood briquette combustion were simultaneously measured. The experimental results at the three measurement heights showed that both peak concentration and the amount of gas-phase potassium released from biomass briquettes decreased with the increase in compaction pressure. Furthermore, the amount of potassium released from biomass briquettes at a compaction pressure of 180 MPa was the lowest at all three measurement heights, at 28.0, 14.5, and 21.8 ppm·s. Moreover, the potassium release rate from 0 to 63 s was rapid, and there was an exponential increase in the release ratio curve. The release ratio of potassium reached 50% before entering the ash stage under a compaction pressure of 80 and 130 MPa; in comparison, it only reached 35% under 180 MPa. The potassium release ratio at HAB = 4 cm under compaction pressures of 80, 130, and 180 MPa was 54%, 50%, and 35%, respectively. The findings of this study directly link compaction pressure to K release and demonstrate the applicability of FES for real-time alkali metal detecting, offering both theoretical and practical pathways toward cleaner biomass combustion.
Ye et al. (Tue,) studied this question.