A model was developed to describe the adsorption characteristic of mercury in flue gas based on one residual carbon sample and one activated carbon sample. The differential equations were established with mass balance...A model was developed to describe the adsorption characteristic of mercury in flue gas based on one residual carbon sample and one activated carbon sample. The differential equations were established with mass balance of mercury in the gas phase and in the solid phase. Then the model was solved using a Matlab program with a Runge-Kutta process. The mercury adsorption isotherms of these two adsorbents were obtained by breakthrough column experiments. The results show that at low gas phase mercury concentrations （ 〈 0. 3 mg/ m^3）, the adsorption equilibrium of residual carbon is in accord with the case of a type Ⅱ isotherm of the Freundich theory. Whereas the data of activated carbon falls into the Langmuir relationship, it is the case of a type Ⅲ isotherm. The experimental data were fitted to the Freundlich model by Matlab software. The variances of mercury concentration are smaller than 0. 81 which implies the agreement between measurements and simulation is quite agreeable considering the wide scatter of the measurements. This model is useful for forecasting mercury removal efficiency and is helpful to the mechanism analysis of mercury adsorption on carbon-based adsorbent.展开更多
More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. Howeve...More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.展开更多
Three fresh China coals （lignitie, bituminite and anthracite） from different geological origin and the corresponding fly and bottom ashes were studied by room temperature（RT） Mossbauer spectroscopy（MS）. The iron...Three fresh China coals （lignitie, bituminite and anthracite） from different geological origin and the corresponding fly and bottom ashes were studied by room temperature（RT） Mossbauer spectroscopy（MS）. The iron-bearing minerals were characterized to be mainly pyrite in all coal samples by the hyperfine parameters.Suphate（FeSO4·nH2O） was found in bituminite and anthracite coal.The MSssbauer spectra of the fly and bottom ashes as a result of pulverised coal combustion（PCC） in Xiaolongtan,Shuicheng and Luohuang Power Plants are comprised of superimposed sextets and doulets of oxides includes maghemite（γ-Fe2O3）, magnitite（Fe3O4）, haematite（α-Fe2O3）, magnesioferite （MgFe2O4）, Fe^3＋/Fe^2＋ -mullite, Fe^3＋ -glass silicate and metallic iron. The studies also show that iron-bearing minerals in coals are largely dependant on geological regions and coal rank, the composition of the corresponding fly and bottom ashes will not only depend on the type and mineralogy of the feed coal but also on the local nature of combustion.展开更多
文摘A model was developed to describe the adsorption characteristic of mercury in flue gas based on one residual carbon sample and one activated carbon sample. The differential equations were established with mass balance of mercury in the gas phase and in the solid phase. Then the model was solved using a Matlab program with a Runge-Kutta process. The mercury adsorption isotherms of these two adsorbents were obtained by breakthrough column experiments. The results show that at low gas phase mercury concentrations （ 〈 0. 3 mg/ m^3）, the adsorption equilibrium of residual carbon is in accord with the case of a type Ⅱ isotherm of the Freundich theory. Whereas the data of activated carbon falls into the Langmuir relationship, it is the case of a type Ⅲ isotherm. The experimental data were fitted to the Freundlich model by Matlab software. The variances of mercury concentration are smaller than 0. 81 which implies the agreement between measurements and simulation is quite agreeable considering the wide scatter of the measurements. This model is useful for forecasting mercury removal efficiency and is helpful to the mechanism analysis of mercury adsorption on carbon-based adsorbent.
文摘More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.
文摘Three fresh China coals （lignitie, bituminite and anthracite） from different geological origin and the corresponding fly and bottom ashes were studied by room temperature（RT） Mossbauer spectroscopy（MS）. The iron-bearing minerals were characterized to be mainly pyrite in all coal samples by the hyperfine parameters.Suphate（FeSO4·nH2O） was found in bituminite and anthracite coal.The MSssbauer spectra of the fly and bottom ashes as a result of pulverised coal combustion（PCC） in Xiaolongtan,Shuicheng and Luohuang Power Plants are comprised of superimposed sextets and doulets of oxides includes maghemite（γ-Fe2O3）, magnitite（Fe3O4）, haematite（α-Fe2O3）, magnesioferite （MgFe2O4）, Fe^3＋/Fe^2＋ -mullite, Fe^3＋ -glass silicate and metallic iron. The studies also show that iron-bearing minerals in coals are largely dependant on geological regions and coal rank, the composition of the corresponding fly and bottom ashes will not only depend on the type and mineralogy of the feed coal but also on the local nature of combustion.
