A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a...A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a NaOH solution bath. The flow field, volumetric mass transfer coefficient per unit volume （Ak/V; where A is the contact area between phases, V is the volume, and k is the mass transfer coeffi- cient）, and gas utilization ratio （t/） were then measured at different gas flow rates and blow angles. The results showed that the flow field could be divided into five regions, i.e., injection, strong loop, weak loop, splashing, and dead zone. Whereas the Ak/V of the bath increased and then decreased with increasing gas flow rate, and n steadily increased. When the converter was rotated clockwise, both Ak/F and t/increased. However, the flow condition deteriorated when the gas flow rate and blow angle were drastically increased. Therefore, these para- meters must be controlled to optimal conditions. In the proposed model, the optimal gas flow rate and blow angle were 7.5 m3.h-1 and 10°, respectively.展开更多
Hydrophobic membrane can provide fast mass transfer for absorption-desorption of gasesform liquid to absorbent.The removal of ammonia from ammonia water and absorption with dilutesulphuric acid was studied in a pilot ...Hydrophobic membrane can provide fast mass transfer for absorption-desorption of gasesform liquid to absorbent.The removal of ammonia from ammonia water and absorption with dilutesulphuric acid was studied in a pilot plant with polypropylene hollow fiber column,The removalrate and influences of operation temperature,flow rate and concentration on mass transferperformances were discussed mathematically.Experimental results and computer calculation show thatthe ammonia removal rate is not affected by the feed concentration for a given system.Both partialand overall mass transfer coefficients vary along the axis of the fiber,and the mass transfer for themembrane process is controlled by membrane resistance.展开更多
Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic co...Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the daily ETo at all weather stations with relative errors that varied from 34% to 94% relative to the FAO-PM ETo estimates. The Penman, Mahringer, Trabert, and the Romanenko equations performed best across Tanzania and the South Western Kenya with root mean squared errors ranging from 0.98 to 1.48 mm/day, which are relatively high and mean bias error (MBE) varying from -0.33 to 0.02 mm/day and the absolute mean error (AME) from 0.79 to 1.16 mm/day. For sustainable water management, the Trabert equation could be adopted at Songea, the Mahringer equation at Tabora, the Dalton and/or the Rohwer equations at Eldoret, the Romanenko equation at Dodoma, Songea and Eldoret. However, regional calibration of the most performing equation could improve water management at regional level.展开更多
为揭示南水北调中线工程水体中溶解性有机质(Dissolved Organic Matter,DOM)的组成变化特征,采集南水北调中线总干渠沿线及丹江口水库水样,利用傅里叶变换离子回旋共振质谱(Fourier Transform Ion Cyclotron Resonance Mass Spectrometr...为揭示南水北调中线工程水体中溶解性有机质(Dissolved Organic Matter,DOM)的组成变化特征,采集南水北调中线总干渠沿线及丹江口水库水样,利用傅里叶变换离子回旋共振质谱(Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,FT-ICR MS)分析了DOM的分子组成及其空间变化,并探讨了总干渠沿线DOM变化成因和环境意义。结果表明:丹江口水库和总干渠均检出DOM物质3200余种,仅含C、H和O的物质(CHOs)为主要组分,约占所有检出物质的61%,含C、H、O和N的物质(CHONs)占30.5%~31.5%,含C、H、O和S的物质(CHOSs)仅占7.3%~8.4%,结合O/C和H/C分类,丹江口水库和总干渠水体DOM主要组分为木质素(60%以上)。相较于丹江口水库,总干渠水体DOM组分发生了较大变化,蛋白质类组分占比由3.70%升至8.65%,表明总干渠中有蛋白质生成;稠环类物质占比由9.43%下降至4.77%,单宁酸类的变化趋势与稠环类物质类似。总干渠局部区域藻类增殖过程是引起总干渠中CHONs和CHOSs类DOM组分和占比升高的主要原因。研究成果可为科学认识南水北调中线工程水体水质变化过程提供科学依据。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51504018)the China Postdoctoral Science Foundation(2015M580986)the Fundamental Research Funds for the Central Universities(FRF-TP-17-038A2)
文摘A water model with a geometric similarity ratio of 1：5 was developed to investigate the gas-liquid mass transfer and flow charac- teristics in a Peirce-Smith converter. A gas mixture of CO2 and Ar was injected into a NaOH solution bath. The flow field, volumetric mass transfer coefficient per unit volume （Ak/V; where A is the contact area between phases, V is the volume, and k is the mass transfer coeffi- cient）, and gas utilization ratio （t/） were then measured at different gas flow rates and blow angles. The results showed that the flow field could be divided into five regions, i.e., injection, strong loop, weak loop, splashing, and dead zone. Whereas the Ak/V of the bath increased and then decreased with increasing gas flow rate, and n steadily increased. When the converter was rotated clockwise, both Ak/F and t/increased. However, the flow condition deteriorated when the gas flow rate and blow angle were drastically increased. Therefore, these para- meters must be controlled to optimal conditions. In the proposed model, the optimal gas flow rate and blow angle were 7.5 m3.h-1 and 10°, respectively.
文摘Hydrophobic membrane can provide fast mass transfer for absorption-desorption of gasesform liquid to absorbent.The removal of ammonia from ammonia water and absorption with dilutesulphuric acid was studied in a pilot plant with polypropylene hollow fiber column,The removalrate and influences of operation temperature,flow rate and concentration on mass transferperformances were discussed mathematically.Experimental results and computer calculation show thatthe ammonia removal rate is not affected by the feed concentration for a given system.Both partialand overall mass transfer coefficients vary along the axis of the fiber,and the mass transfer for themembrane process is controlled by membrane resistance.
文摘Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the daily ETo at all weather stations with relative errors that varied from 34% to 94% relative to the FAO-PM ETo estimates. The Penman, Mahringer, Trabert, and the Romanenko equations performed best across Tanzania and the South Western Kenya with root mean squared errors ranging from 0.98 to 1.48 mm/day, which are relatively high and mean bias error (MBE) varying from -0.33 to 0.02 mm/day and the absolute mean error (AME) from 0.79 to 1.16 mm/day. For sustainable water management, the Trabert equation could be adopted at Songea, the Mahringer equation at Tabora, the Dalton and/or the Rohwer equations at Eldoret, the Romanenko equation at Dodoma, Songea and Eldoret. However, regional calibration of the most performing equation could improve water management at regional level.
文摘为揭示南水北调中线工程水体中溶解性有机质(Dissolved Organic Matter,DOM)的组成变化特征,采集南水北调中线总干渠沿线及丹江口水库水样,利用傅里叶变换离子回旋共振质谱(Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,FT-ICR MS)分析了DOM的分子组成及其空间变化,并探讨了总干渠沿线DOM变化成因和环境意义。结果表明:丹江口水库和总干渠均检出DOM物质3200余种,仅含C、H和O的物质(CHOs)为主要组分,约占所有检出物质的61%,含C、H、O和N的物质(CHONs)占30.5%~31.5%,含C、H、O和S的物质(CHOSs)仅占7.3%~8.4%,结合O/C和H/C分类,丹江口水库和总干渠水体DOM主要组分为木质素(60%以上)。相较于丹江口水库,总干渠水体DOM组分发生了较大变化,蛋白质类组分占比由3.70%升至8.65%,表明总干渠中有蛋白质生成;稠环类物质占比由9.43%下降至4.77%,单宁酸类的变化趋势与稠环类物质类似。总干渠局部区域藻类增殖过程是引起总干渠中CHONs和CHOSs类DOM组分和占比升高的主要原因。研究成果可为科学认识南水北调中线工程水体水质变化过程提供科学依据。
