Refined carbon(RC) derived from coal fly ash(CFA) as well as powdered activated carbon(PAC) was investigated as adsorbent to remove residual amine collector HAY from aqueous solution.The RC and PAC were characterized ...Refined carbon(RC) derived from coal fly ash(CFA) as well as powdered activated carbon(PAC) was investigated as adsorbent to remove residual amine collector HAY from aqueous solution.The RC and PAC were characterized by scanning electron microscopy(SEM),surface area measurement,Zeta potential measurement and Fourier transform infrared(FTIR) spectroscopy.The effect factors and mechanisms of HAY adsorption onto RC and PAC were studied in detail.The results show that the experimental kinetic data agree well with the pseudo second-order equation,and the Langmuir isotherm model is found to be more appropriate to explicate the experimental equilibrium isotherm results than the Freundlich model.The adsorption capacities of PAC and RC increase with pH.It is found that alkaline condition is conducive to the adsorption of HAY onto PAC and RC and the adsorption efficiency of RC is close to PAC at pH near 11.Zeta potential variation of adsorbents suggests that HAY generates electrostatic adsorption onto RC and PAC.FTIR analysis shows that the adsorption is dominantly of a physical process.The Box-Behnken design optimization conditions of process are RC 1 g/L,pH 11,temperature 302 K and initial HAY concentration 100 mg/L.Under these conditions,the measured adsorption ratio and adsorption capacity are 87.91%and 87.91 mg/g,respectively.Thus,the RC is considered to be a potential adsorbent for the removal of residual amine from aqueous solution.展开更多
The unburned carbon concentration in fly ash and the influence of main factors on the reduction of nitrogen oxides during gaseous fuel reburning process were experimentally studied in a 36 kW down-fired furnace when f...The unburned carbon concentration in fly ash and the influence of main factors on the reduction of nitrogen oxides during gaseous fuel reburning process were experimentally studied in a 36 kW down-fired furnace when five typical coals with different qualities were served as the primary fuel. It is found that the higher nitrogen oxide reduction efficiency can be obtained by reburning process when the coal used as the primary fuel contains more volatile matter. But under the optimizational operating conditions, both above 50% nitrogen oxide reduction and low carbon loss can be achieved by reburning process even though the primary fuel is the low-volatile coal. The experimental results show that the reasonable residence time in reburn zone is 0.6-0.9 s, the appropriate gaseous reburn fuel percentage is 10%-15% and the optimal average excess air coefficient in reburn zone is 0.8-0.9. These results extend the ranges of the key parameter values for reburning process with respect to that the low-volatile coals are used as the primary fuel.展开更多
The carbon sorbent traps method was used to monitor the mercury content and speciation underhigh-temperature and high-ash content conditions that are beyond the allowable conditions of the EPAMethod 30B,to extend its ...The carbon sorbent traps method was used to monitor the mercury content and speciation underhigh-temperature and high-ash content conditions that are beyond the allowable conditions of the EPAMethod 30B,to extend its application range.The results show that,when measuring the total mercury con-centration in flue gas,this method can be applied to the occasions of high dust concentration(e.g.beforethe WFGD system),with the error caused by dust lower than 1%,if keeping the flow rate at a lower leveland employing dustproof cover.But this method is not suitable to the conditions with extreme high dustcontent.By applying air-cooled casing and controlling the sampling gun's insert depth,the temperature ofcarbon traps can be kept within a suitable range.Thus,the measurement accuracy of mercury concentrationbefore air preheater can be ensured.For the chimney inlet and other areas with low dust concentration,theproportion of Hg°measured by the 30B method is in accordance with the Hg-CEMS after the WFGD sys-tem,while after the CFB-FGD system,the proportion of Hg°measured by the 30B method is slightly lowerthan that by the Hg-CEMS method.For locations with high dust concentration,the proportion of Hg°measured by the 30B method may be much lower than the true value.展开更多
基金Projects(2013BAB07B03,2013BAC15B01)supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of ChinaProject(51264005)supported by the National Natural Science Foundation of China+1 种基金Project(Qiankehejz[2014]2009)supported by the Key Foundation of Science and Technology of Guizhou Province,ChinaProject([2013]019)supported by“125”Major Special Project of Guizhou Province,China
文摘Refined carbon(RC) derived from coal fly ash(CFA) as well as powdered activated carbon(PAC) was investigated as adsorbent to remove residual amine collector HAY from aqueous solution.The RC and PAC were characterized by scanning electron microscopy(SEM),surface area measurement,Zeta potential measurement and Fourier transform infrared(FTIR) spectroscopy.The effect factors and mechanisms of HAY adsorption onto RC and PAC were studied in detail.The results show that the experimental kinetic data agree well with the pseudo second-order equation,and the Langmuir isotherm model is found to be more appropriate to explicate the experimental equilibrium isotherm results than the Freundlich model.The adsorption capacities of PAC and RC increase with pH.It is found that alkaline condition is conducive to the adsorption of HAY onto PAC and RC and the adsorption efficiency of RC is close to PAC at pH near 11.Zeta potential variation of adsorbents suggests that HAY generates electrostatic adsorption onto RC and PAC.FTIR analysis shows that the adsorption is dominantly of a physical process.The Box-Behnken design optimization conditions of process are RC 1 g/L,pH 11,temperature 302 K and initial HAY concentration 100 mg/L.Under these conditions,the measured adsorption ratio and adsorption capacity are 87.91%and 87.91 mg/g,respectively.Thus,the RC is considered to be a potential adsorbent for the removal of residual amine from aqueous solution.
基金Projects(50806025 50721005) supported by the National Natural Science Foundation of China
文摘The unburned carbon concentration in fly ash and the influence of main factors on the reduction of nitrogen oxides during gaseous fuel reburning process were experimentally studied in a 36 kW down-fired furnace when five typical coals with different qualities were served as the primary fuel. It is found that the higher nitrogen oxide reduction efficiency can be obtained by reburning process when the coal used as the primary fuel contains more volatile matter. But under the optimizational operating conditions, both above 50% nitrogen oxide reduction and low carbon loss can be achieved by reburning process even though the primary fuel is the low-volatile coal. The experimental results show that the reasonable residence time in reburn zone is 0.6-0.9 s, the appropriate gaseous reburn fuel percentage is 10%-15% and the optimal average excess air coefficient in reburn zone is 0.8-0.9. These results extend the ranges of the key parameter values for reburning process with respect to that the low-volatile coals are used as the primary fuel.
基金The Science and Technology Project in China Huaneng Group:“Mercury Control Technology R&D Laboratory Construction”
文摘The carbon sorbent traps method was used to monitor the mercury content and speciation underhigh-temperature and high-ash content conditions that are beyond the allowable conditions of the EPAMethod 30B,to extend its application range.The results show that,when measuring the total mercury con-centration in flue gas,this method can be applied to the occasions of high dust concentration(e.g.beforethe WFGD system),with the error caused by dust lower than 1%,if keeping the flow rate at a lower leveland employing dustproof cover.But this method is not suitable to the conditions with extreme high dustcontent.By applying air-cooled casing and controlling the sampling gun's insert depth,the temperature ofcarbon traps can be kept within a suitable range.Thus,the measurement accuracy of mercury concentrationbefore air preheater can be ensured.For the chimney inlet and other areas with low dust concentration,theproportion of Hg°measured by the 30B method is in accordance with the Hg-CEMS after the WFGD sys-tem,while after the CFB-FGD system,the proportion of Hg°measured by the 30B method is slightly lowerthan that by the Hg-CEMS method.For locations with high dust concentration,the proportion of Hg°measured by the 30B method may be much lower than the true value.
