Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In thi...Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In this study,VOC emission factors,O3 and SOA formation potentials were estimated for two types of industrial boilers:coal-fired boilers(n=3)and oil-fired boilers(n=3).Results showed that EVOCs concentrations were more than nine times higher for oil-fire d boilers compared to those for coal-fired boilers.Emission factors ofΣVOCs were found to be higher for oil-fired boilers(9.26-32.83 mg-VOC/kg)than for coal-fired boilers(1.57-4.13 mg-VOC/kg).Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers,while oxygenated organics and aromatics were the most contributing groups in oil-fired boilers.Benzene,n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions,whereas toluene was the most abundant VOC species emitted from oil-fired boilers.O3 and SOA formation potentials were found 12 and 18 times,respectively,higher for oil-fired than for coal-fired boilers.Total OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired boilers.For oil-fired boilers,total OFP ranged from 36.16 to 131.93 mg-O3/kg.Moreover,total secondary organic aerosol potential(SOAP)ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers,respectively.展开更多
In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of ...In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of the boiler.The system comprises two parts:the USCFB boiler model and a tracking mechanism based on sliding mode control algorithm.The USCFB boiler model includes a water-steam system,an air-flue gas system,a material supply system,and an ash circulation system.The online tracking simulation system receives the same control signal as the plant and runs synchronously in digital space.The tracking mechanism updates model parameters to eliminate deviations between simulation values and measured values.The SMC-based multi-input,multi-output algorithm is based on a state-space model,providing two distinct advantages.Firstly,it enables more efficient elimination of deviations;secondly,it exhibits robustness against uncertainties associated with simulation model behavior and measurement noise.Finally,this paper conducts tracking simulation research on the cold start-up process of the boiler.展开更多
In order to achieve the target of reducing oil consumption to zero for pulverized coal(PC)boiler in power plant,the paper developed a novel coal pulverized ignition approach,called as Alternating-Current plasma(AC pla...In order to achieve the target of reducing oil consumption to zero for pulverized coal(PC)boiler in power plant,the paper developed a novel coal pulverized ignition approach,called as Alternating-Current plasma(AC plasma)ignition,with the advantages of excellent PC combustion behavior and longer electrode life-span.The scientific principle of how to generate the AC plasma arc was elaborated in detail.First,the experiments on life-span of electrodes inside AC plasma generator had been conducted,finding a workable way to extend its life-span beyond 530 hours.Second,a new AC plasma burner specifically designed for lean coal according to the principle of PC staged combustion had been illustrated with diagrams and then used to ignite the PC-air stream under four kinds of conditions with a varying AC plasma power from 150 kW to 300 kW,focusing on analyses of the influence of AC plasma power on combustion behaver,such as combustion temperature,carbon burnout rate as well as PC combustion regime.The following results showed that in the case of the power of the AC plasma was P=300 kW,a satisfied PC combustion process could achieved,with the average PC combustion temperature of about 940°C,combustion flame length of 6.3 m,and the total carbon burnout rate of up to 52.2%.In addition,about 80%of the nozzle outlet section was filled with bright flame,while 81%of the PC was in zone of the cylindrical flame regime.The PC combustion modes were changed repeatedly during the process of combustion,which went from homogeneous combustion mode at initial ignition stage to combined combustion mode and heterogeneous combustion mode at middle stage,finally to combined combustion mode at later stage.The research conclusion in this paper has proved that the AC plasma ignition approach is feasible and effective to ignite low-rank coal without the present of fuel oil.展开更多
文摘Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In this study,VOC emission factors,O3 and SOA formation potentials were estimated for two types of industrial boilers:coal-fired boilers(n=3)and oil-fired boilers(n=3).Results showed that EVOCs concentrations were more than nine times higher for oil-fire d boilers compared to those for coal-fired boilers.Emission factors ofΣVOCs were found to be higher for oil-fired boilers(9.26-32.83 mg-VOC/kg)than for coal-fired boilers(1.57-4.13 mg-VOC/kg).Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers,while oxygenated organics and aromatics were the most contributing groups in oil-fired boilers.Benzene,n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions,whereas toluene was the most abundant VOC species emitted from oil-fired boilers.O3 and SOA formation potentials were found 12 and 18 times,respectively,higher for oil-fired than for coal-fired boilers.Total OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired boilers.For oil-fired boilers,total OFP ranged from 36.16 to 131.93 mg-O3/kg.Moreover,total secondary organic aerosol potential(SOAP)ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers,respectively.
文摘In this paper,an online tracking simulation system for the 660 MW ultra-supercritical circulating fluidized bed(USCFB)boiler is established,and a tracking simulation test is conducted for the cold start-up process of the boiler.The system comprises two parts:the USCFB boiler model and a tracking mechanism based on sliding mode control algorithm.The USCFB boiler model includes a water-steam system,an air-flue gas system,a material supply system,and an ash circulation system.The online tracking simulation system receives the same control signal as the plant and runs synchronously in digital space.The tracking mechanism updates model parameters to eliminate deviations between simulation values and measured values.The SMC-based multi-input,multi-output algorithm is based on a state-space model,providing two distinct advantages.Firstly,it enables more efficient elimination of deviations;secondly,it exhibits robustness against uncertainties associated with simulation model behavior and measurement noise.Finally,this paper conducts tracking simulation research on the cold start-up process of the boiler.
基金supported by the national natural science foundation of china(Contract No.51806132)doctor start-up capital of Shanxi University(No.20174462)。
文摘In order to achieve the target of reducing oil consumption to zero for pulverized coal(PC)boiler in power plant,the paper developed a novel coal pulverized ignition approach,called as Alternating-Current plasma(AC plasma)ignition,with the advantages of excellent PC combustion behavior and longer electrode life-span.The scientific principle of how to generate the AC plasma arc was elaborated in detail.First,the experiments on life-span of electrodes inside AC plasma generator had been conducted,finding a workable way to extend its life-span beyond 530 hours.Second,a new AC plasma burner specifically designed for lean coal according to the principle of PC staged combustion had been illustrated with diagrams and then used to ignite the PC-air stream under four kinds of conditions with a varying AC plasma power from 150 kW to 300 kW,focusing on analyses of the influence of AC plasma power on combustion behaver,such as combustion temperature,carbon burnout rate as well as PC combustion regime.The following results showed that in the case of the power of the AC plasma was P=300 kW,a satisfied PC combustion process could achieved,with the average PC combustion temperature of about 940°C,combustion flame length of 6.3 m,and the total carbon burnout rate of up to 52.2%.In addition,about 80%of the nozzle outlet section was filled with bright flame,while 81%of the PC was in zone of the cylindrical flame regime.The PC combustion modes were changed repeatedly during the process of combustion,which went from homogeneous combustion mode at initial ignition stage to combined combustion mode and heterogeneous combustion mode at middle stage,finally to combined combustion mode at later stage.The research conclusion in this paper has proved that the AC plasma ignition approach is feasible and effective to ignite low-rank coal without the present of fuel oil.
