Cyclic total reflux(CTR) batch distillation is a promising mode of the process but lacking of appropriate modeling for the period of filling the reflux drum.A new dynamic modeling method for the simulation of CTR batc...Cyclic total reflux(CTR) batch distillation is a promising mode of the process but lacking of appropriate modeling for the period of filling the reflux drum.A new dynamic modeling method for the simulation of CTR batch distillation is proposed in this work,in which the changes in column holdup and liquid flow rate during the filling of the drum,and the consequent change in valid number of theoretical plates are considered.The effect of drum holdup on operation time is investigated and the optimal drum holdup is obtained from the simulation.The dynamic modeling is compared to the conventional modeling without consideration of change in liquid flow rate. The experimental result shows that the present modeling is more reliable and more accurate,especially for the column with large liquid holdup.展开更多
This paper reports an investigation of Computational Fluid Dynamics(CFD)on the influence of injection momentum rate of premixed air and fuel on the flameless Moderate or Intense Low oxygen Dilution(MILD) combustion in...This paper reports an investigation of Computational Fluid Dynamics(CFD)on the influence of injection momentum rate of premixed air and fuel on the flameless Moderate or Intense Low oxygen Dilution(MILD) combustion in a recuperative furnace.Details of the furnace flow velocity,temperature,O2,CO2 and NOx concentrations are provided.Results obtained suggest that the flue gas recirculation plays a vital role in establishing the premixed MILD combustion.It is also revealed that there is a critical momentum rate of the fuel-air mixture below which MILD combustion does not occur.Moreover,the momentum rate appears to have less significant influence on conventional global combustion than on MILD combustion.展开更多
The paper analyzes different turbine design suitable for the urban environment. The author discusses various options for setting up wind turbines in relation to the building. In order to gain insight into the real ind...The paper analyzes different turbine design suitable for the urban environment. The author discusses various options for setting up wind turbines in relation to the building. In order to gain insight into the real indicators, considered are actual examples of wind turbines mounted on buildings, sports facilities, roads, etc. However, these turbines have relatively low efficiency and a long payback period, and the problem may be the noise they produce. Therefore, the wind turbines installed in buildings are still more a matter of prestige of individual investors and architects than profitable investment.展开更多
Biochars are, amongst other available amendment materials, considered as an attractive tool in agriculture for carbon sequestration and improvement of soil functions. The latter is widely discussed as a consequence of...Biochars are, amongst other available amendment materials, considered as an attractive tool in agriculture for carbon sequestration and improvement of soil functions. The latter is widely discussed as a consequence of improved physical quality of the amended soil.However, the mechanisms for this improvement are still poorly understood. This study investigated the effect of woodchip biochar amendment on micro-structural development, micro-and macro-structural stability, and resilience of two differently textured soils,fine sand(FS) and sandy loam(SL). Test substrates were prepared by adding 50 or 100 g kg^(-1) biochar to FS or SL. Total porosity and plant available water were significantly increased in both soils. Moreover, compressive strength of the aggregates was significantly decreased when biochar amount was doubled. Mechanical resilience of the aggregates at both micro-and macro-scale was improved in the biochar-amended soils, impacting the cohesion and compressive behavior. A combination of these effects will result in an improved pore structure and aeration. Consequently, the physicochemical environment for plants and microbes is improved. Furthermore, the improved stability properties will result in better capacity of the biochar-amended soil to recover from the myriad of mechanical stresses imposed under arable systems, including vehicle traffic, to the weight of overburden soil. However, it was noted that doubling the amendment rate did not in any case offer any remarkable additional improvement in these properties, suggesting a further need to investigate the optimal amendment rate.展开更多
文摘Cyclic total reflux(CTR) batch distillation is a promising mode of the process but lacking of appropriate modeling for the period of filling the reflux drum.A new dynamic modeling method for the simulation of CTR batch distillation is proposed in this work,in which the changes in column holdup and liquid flow rate during the filling of the drum,and the consequent change in valid number of theoretical plates are considered.The effect of drum holdup on operation time is investigated and the optimal drum holdup is obtained from the simulation.The dynamic modeling is compared to the conventional modeling without consideration of change in liquid flow rate. The experimental result shows that the present modeling is more reliable and more accurate,especially for the column with large liquid holdup.
基金Supported by the National Natural Science Foundation of China(50936001)
文摘This paper reports an investigation of Computational Fluid Dynamics(CFD)on the influence of injection momentum rate of premixed air and fuel on the flameless Moderate or Intense Low oxygen Dilution(MILD) combustion in a recuperative furnace.Details of the furnace flow velocity,temperature,O2,CO2 and NOx concentrations are provided.Results obtained suggest that the flue gas recirculation plays a vital role in establishing the premixed MILD combustion.It is also revealed that there is a critical momentum rate of the fuel-air mixture below which MILD combustion does not occur.Moreover,the momentum rate appears to have less significant influence on conventional global combustion than on MILD combustion.
文摘The paper analyzes different turbine design suitable for the urban environment. The author discusses various options for setting up wind turbines in relation to the building. In order to gain insight into the real indicators, considered are actual examples of wind turbines mounted on buildings, sports facilities, roads, etc. However, these turbines have relatively low efficiency and a long payback period, and the problem may be the noise they produce. Therefore, the wind turbines installed in buildings are still more a matter of prestige of individual investors and architects than profitable investment.
基金the George Foster Research Fellowship provided by Alexander yon Humboldt Fellowship of Germany.
文摘Biochars are, amongst other available amendment materials, considered as an attractive tool in agriculture for carbon sequestration and improvement of soil functions. The latter is widely discussed as a consequence of improved physical quality of the amended soil.However, the mechanisms for this improvement are still poorly understood. This study investigated the effect of woodchip biochar amendment on micro-structural development, micro-and macro-structural stability, and resilience of two differently textured soils,fine sand(FS) and sandy loam(SL). Test substrates were prepared by adding 50 or 100 g kg^(-1) biochar to FS or SL. Total porosity and plant available water were significantly increased in both soils. Moreover, compressive strength of the aggregates was significantly decreased when biochar amount was doubled. Mechanical resilience of the aggregates at both micro-and macro-scale was improved in the biochar-amended soils, impacting the cohesion and compressive behavior. A combination of these effects will result in an improved pore structure and aeration. Consequently, the physicochemical environment for plants and microbes is improved. Furthermore, the improved stability properties will result in better capacity of the biochar-amended soil to recover from the myriad of mechanical stresses imposed under arable systems, including vehicle traffic, to the weight of overburden soil. However, it was noted that doubling the amendment rate did not in any case offer any remarkable additional improvement in these properties, suggesting a further need to investigate the optimal amendment rate.
