| As a resourceful refreshable energy resource, biomass energy is getting more and moreattention. However, some problems still exist in application of biomass energy, as electricpower generation, phenomena such as ash deposition, slagging and high temperaturecorrosion are still evident. In order to solve those problems, some scholars suggested thatpretreatment such as water scrubbing could be employed to decrease the content ofelements K, Na and Cl in biomass. Other researches showed that oxy-fuel combustioncould increase the stability of biomass combustion. This thesis combines oxy-fuelcombustion and water scrubbing pretreatment together to mainly research on two aspects ofalkali metallic species influences on the ignition temperature and partical emission ofbiomass under O2/CO2atmosphere.Firstly, dislodge most of the alkali metal inside biomass through water scrubbing.Then put both pre-water scrubbed and post-water scrubbed samples on Wire-mesh reactorand run ignition temperature test with O2/N2gas to get impact on ignition temperature ofbiomass from different contents of alkali metal. The results indicated that water scrubbingcould largely increase the ignition temperature of the biomass sample.Then put both pre-water scrubbed and post-water scrubbed samples on drop tubefurnace and burn them with O2/N2and O2/CO2gas to collect particulate matters. Weight thecollected particulate matters and analyze with X-ray Fluorescence Spectrometer to get masssize distribution and elemental composition distribution. The results indicated thatparticulate matters size distribution generated by biomass combustion also shown asapparent bimodal distribution, which would not be effected by water scrubbing or changeof gas. Water scrubbing restraints generation of submicron and super-micron particulatematters. Compared to O2/N2, O2/CO2gas has stronger restraint effect on generation ofsuper-micron particulate matters. |
