Ensuring a sufficient energy supply is essential to a country. Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a ...Ensuring a sufficient energy supply is essential to a country. Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a country＇s energy policy. Over the years, studies have shown that a combinative model gives better projected results compared to a single model. In this study, we used Polynomial Curve and Moving Average Combination Projection （PCMACP） model to estimate the future natural gas consumption in China from 2009 to 2015. The new proposed PCMACP model shows more reliable and accurate results： its Mean Absolute Percentage Error （MAPE） is less than those of any previous models within the investigated range. According to the PCMACP model, the average annual growth rate will increase for the next 7 years and the amount of natural gas consumption will reach 171600 million cubic meters in 2015 in China.展开更多
Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas proj...Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas project(CGP)to improve the air quality in northern China.As a subcompany of China National Petroleum Corporation,PetroChina Natural Gas Marketing North Company has been focusing on natural gas resource allocation while considering numerous issues such as ensuring the bottom line of livelihood requirements in winter and the performance of economic indicators for an entire calendar year in the northern part of China.Therefore,the accurate prediction of natural gas consumption is important to PetroChina Natural Gas Marketing North Company.It has become a challenge to forecast natural gas consumption because the natural gas market has changed considerably because of the CGP.Natural gas consumption cannot be forecasted using conventional models.This study analyzes the characteristics of the CGP based on the data obtained from rural individual users and company users.Based on the analysis,the gas consumption in winter is predicted using two different forecasting approaches.The methods presented in this paper provide a basis for formulating effective measures for natural gas scheduling in the northern part of China.展开更多
In recent years,China has developed rapidly in terms of natural gas.Driven by regional economic integration,a regional natural gas market composed of neighboring provinces and cities has taken shape gradually,and it t...In recent years,China has developed rapidly in terms of natural gas.Driven by regional economic integration,a regional natural gas market composed of neighboring provinces and cities has taken shape gradually,and it tends to grow toward the same direction in policy formulation,resource coordination,facility construction and market expansion.Based on the factors such as geographical location,economic conditions and natural gas consumption,this thesis tends to conduct a horizontal comparative analysis on the economic development conditions,natural gas consumption characteristics and natural gas pipeline network density of the three regions with obvious regional integration feature in China.Then according to LMDI,four core indicators,namely economic growth effect,energy intensity effect,energy structure effect,and substitution effect are selected.The thesis is expected to explore the contribution of different indicators to the growth of natural gas consumption in these three different regions.According to the results,it can be concluded that the driving factors of natural gas consumption differ greatly among regions.Specifically speaking,the more developed the economy is,the greater the contribution of the energy substitution effect to natural gas consumption will be,and the contribution of the economic growth effect to natural gas consumption will be smaller.Despite that the contribution of energy intensity in different regions shows slight difference,the energy structure contributes the least effect,which further explains the current differences in China’s natural gas consumption characteristics and the reasons behind.展开更多
In view of the abrupt and phased features of natural gas consumption,this paper attempts to predict natural gas consumption in China with a refined forecasting approach.First,we establish a Markov switching(MS)model t...In view of the abrupt and phased features of natural gas consumption,this paper attempts to predict natural gas consumption in China with a refined forecasting approach.First,we establish a Markov switching(MS)model to identify the phase characteristics after eliminating change points in the natural gas consumption sequence,using the product partition model(PPM).The results show that there are"rapid growth"and"slow growth"regimes in the development process of natural gas consumption in China.Second,the Bayesian model average(BMA)method is employed to determine the core determinants of natural gas consumption under sub-regimes,and it is determined that there are significant differences in the influencing factors under different regimes and periods.Third,this paper establishes the BMA model of the"rapid growth"regime after predicting the state of future natural gas consumption in China.We find that,compared to some other models,the BMA model that fully recognizes the regime without considering change points has the best predictive performance.Finally,the results of static and dynamic scenario analyses show that natural gas consumption continues to rise in 2019 and has obvious seasonal charac-teristics,while possible ultra-rapid growth of consumption in the future provides a new requirement for the supply of natural gas.展开更多
As a kind of clean energy which creates little carbon dioxide, natural gas will play a key role in the process of achieving “Peak Carbon Dioxide Emission” and “Carbon Neutrality”. The Long-range Energy Alternative...As a kind of clean energy which creates little carbon dioxide, natural gas will play a key role in the process of achieving “Peak Carbon Dioxide Emission” and “Carbon Neutrality”. The Long-range Energy Alternatives Planning System(LEAP) model was improved by using new parameters including comprehensive energy efficiency and terminal effective energy consumption. The Back Propagation(BP) Neural Network–LEAP model was proposed to predict key data such as total primary energy consumption, energy mix, carbon emissions from energy consumption, and natural gas consumption in China. Moreover, natural gas production in China was forecasted by the production composition method. Finally, based on the forecast results of natural gas supply and demand, suggestions were put forward on the development of China’s natural gas industry under the background of “Dual Carbon Targets”. The research results indicate that under the background of carbon peak and carbon neutrality, China’s primary energy consumption will peak(59.4×10^(8)tce) around 2035, carbon emissions from energy consumption will peak(103.4×10^(8)t) by 2025, and natural gas consumption will peak(6100×10^(8)m^(3)) around 2040, of which the largest increase will be contributed by the power sector and industrial sector. China’s peak natural gas production is about(2800–3400)×10^(8)m^(3), including(2100–2300)×10^(8)m^(3)conventional gas(including tight gas),(600–1050)×10^(8)m^(3)shale gas, and(150–220)×10^(8)m^(3)coalbed methane. Under the background of carbon peak and carbon neutrality, the natural gas consumption and production of China will further increase, showing a great potential of the natural gas industry.展开更多
In view of the heterogeneity of natural gas consumption in different sectors in China,this paper utilizes Bayesian network(BN)to study the driving factors of natural gas consumption in power generation,chemical and in...In view of the heterogeneity of natural gas consumption in different sectors in China,this paper utilizes Bayesian network(BN)to study the driving factors of natural gas consumption in power generation,chemical and industrial fuel sectors.Combined with Bayesian model averaging(BMA)and scenario analysis,the gas consumption of the three sectors is predicted.The results show that the expansion of urbanization will promote the gas consumption of power generation.The optimization of industrial structure and the increase of industrial gas consumption will enhance the gas consumption of chemical sector.The decrease of energy intensity and the increase of gas consumption for power generation will promote the gas consumption of industrial fuel.Moreover,the direct influencing factors of gas price are urbanization,energy structure and energy intensity.The direct influencing factors of environmental governance intensity are gas price,urbanization,industrial structure,energy intensity and energy structure.In 2025,under the high development scenario,China’s gas consumption for power generation,chemical and industrial fuel sectors will be 66.034,36.552 and 109.414 billion cubic meters respectively.From 2021 to 2025,the average annual growth rates of gas consumption of the three sectors will be 4.82%,2.18%and 4.43%respectively.展开更多
The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption...The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption, greenhouse gas emissions and associated costs. The aim of this study is to determine the energy and cost saving opportunities for truck haulage operations associated with the payload variance in surface mines. The results indicate that there is a non-linear relationship between the payload variance and the fuel consumption, greenhouse gas emissions and associated costs. A correlation model, which is independent of haul road conditions, has been developed between the payload variance and the cost saving using the data from an Australian surface coal mine. The results of analysis for this particular mine show that a significant saving of fuel and greenhouse gas emissions costs is possible if the standard deviation of payload is reduced from the maximum to minimum value.展开更多
The reserves, distribution, production and utilization of natural gas resources in China are introduced in this paper which leads a point of view that China＇s natural gas resources are relatively rich while distribut...The reserves, distribution, production and utilization of natural gas resources in China are introduced in this paper which leads a point of view that China＇s natural gas resources are relatively rich while distributed unevenly. The future production and consumption of China＇s natural gas are predicted using the Generalized Weng model and the Gray prediction model. The prediction suggests that with the increasing gas consumption China＇s natural gas production will not meet demand after 2010. In order to ease the supply-demand gap and realize rational development and utilization of China＇s natural gas resources, this paper puts forward some measures, such as using advanced technologies for natural gas development, establishing a long-distance pipeline network to rationalize the availability of natural gas across China and importing foreign natural gas and liquid natural gas （LNG）.展开更多
Electrocatalysis, as a typical heterogeneous catalysis, generally occurs in the di-or tri-phase interfaces.Wettability is an important property for describing the balance of a gas-liquid-solid system. Therefore,the we...Electrocatalysis, as a typical heterogeneous catalysis, generally occurs in the di-or tri-phase interfaces.Wettability is an important property for describing the balance of a gas-liquid-solid system. Therefore,the wettability of reaction interface, especially hydrophilicity/hydrophobicity, plays an important role in the adsorption/desorption process of gas bubbles on the surface of the solid electrode. Herein, we present a comprehensive review of the wettability control of the electrode materials applied in electrocatalysis reactions, including hydrogen evolution reaction(HER), oxygen evolution reaction(OER), oxygen reduction reaction(ORR) and carbon dioxide reduction reaction(CO_(2) RR). Firstly, the basic theories of wettability as well as the impact on electrocatalysis were introduced in this review. Secondly, the overview of modifying methods of the wettability from electrocatalyst microstructure(structural modification, surface coating, introducing hydrophilic groups) and system design(electrode, device) were suggested. At last, the deficiencies and problems in the application of wettability control are discussed,and deeper and broader application prospects are proposed.展开更多
Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts ...Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts design does.Herein the consumption behavior of an individual oxygen bubble on Pt foils with different wettabilities during ORR was tracked by a real-time approach to reveal whether the surface wettability of electrode can influence the consumption dynamics and determine the reaction reactive zones of oxygen bubble consumption.The oxygen bubble underwent a "constant contact angle"dominant consumption model on aerophobic Pt foil,while an initial "constant radius"and the subsequent"constant contact angle"oxygen consumption models were observed on aero philic Pt foil.Results here demonstrated that the current was proportional to the bottom contact area,rather than the three-phase contact line of the bubbles according to the fitting curves between individual bubble current and the consumption behavior parameters.This study highlights the important role of the gas-solid interface in influencing the efficiency of gas consumption electrochemical reactions,which shall benefit the understanding of reaction kinetics and the rational design of electrocatalysts.展开更多
Top gas recycling oxygen blast furnace（TGR-OBF）process is a promising ironmaking process.The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume（per ton hot metal）,which once l...Top gas recycling oxygen blast furnace（TGR-OBF）process is a promising ironmaking process.The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume（per ton hot metal）,which once led to hanging-up and shutdowns in practice of the Toulachermet.In order to avoid this weakness,the strategy of medium oxygen blast furnace was presented.The maneuverable zone of the TGR-OBF was determined by the top gas volume,which should not be far from the data of the traditional blast furnace.The deviation of ±12.5% was used,and then the maneuverable blast oxygen content is from 0.30 to 0.47 according to the calculation.The flame temperature and the top gas volume have no much difference compared to those of the traditional blast furnace.The minimum carbon consumption of 357 kg per ton hot metal in the maneuverable zone occurs at the oxygen content of 0.30（fuel saving of 14%）.In the unsteady evolution,the N2 accumulation could approach nearly zero after the recycling reached 6 times.Thus far,some TGR-OBF industrial trials have been carried out in different countries,but the method of medium oxygen enriched TGR-OBF has not been implemented,because the accumulation of N2 was worried about.The presented strategy of medium oxygen enriched TGR-OBF is applicable and the strategy with good operational performance is strongly suggested as a forerunner of the full oxygen blast furnace.展开更多
The conventional grey GM(2,1)model built for the fast growing time sequence generally has big errors.To improve the modeling precision,the paper improves from the following two aspects:First,the paper transforms the a...The conventional grey GM(2,1)model built for the fast growing time sequence generally has big errors.To improve the modeling precision,the paper improves from the following two aspects:First,the paper transforms the accumulated generating sequence of original time sequence quantitatively to make the transformed time sequence have the better adaptability to the model;second,the paper extends the conventional grey GM(2,1)model’s structure to make the extended model meet the variation law of fast growing sequence better.The extended grey model is called the GM(2,1,Σexp(ct))model.The paper offers the parameter optimization method and the solving method of time response sequence of GM(2,1,Σexp(ct))model.Using the model and methods proposed,the paper builds the GM(2,1,Σexp(ct))models for the natural gas consumption of China and Chongqing City,China,respectively.Results show that the models built have high simulation precision and prediction precision.展开更多
To improve the prediction accuracy of heating demand, an appropriate base temperature should be estimated before using the heating degree-days (HDD) approach. This study collected the measured data for gas consumption...To improve the prediction accuracy of heating demand, an appropriate base temperature should be estimated before using the heating degree-days (HDD) approach. This study collected the measured data for gas consumption at half-hourly resolution and the building physical characteristics from 89 educational buildings over four years. To determine the base temperature, in addition to the ambient temperature, more detailed independent variables, i.e. solar insolation, relative humidity, wind speed, and one-day ahead residual temperature, were incorporated into a three-parameter change-point multi-variable regression (3PH-MVR) for heating. The mean base temperature using the 3PH-MVR approach was about 0.4℃ lower than the results from the 3PH method only. The relationships between base temperature and annual HDD (based on 15.5℃), building location, and mean daily solar insolation were evaluated. It is found that the annual HDD and the daily insolation had clear impacts on base temperature, while there was a plausible relationship between base temperature and building location. Compared with traditional approach, the proposed 3PH-MVR method considers multiple weather parameters and determines a more robust base temperature, thus improving the prediction accuracy of HDD with higher average R2 value at 0.86 than that of univariate regression (0.82).展开更多
基金supported by the Youth Fund of Chinese Academy of Sciences Knowledge Innovation Program area frontier projects (No. S200603)the Innovation Team Project of Education Department of Liaoning Province (No. 2007T050)
文摘Ensuring a sufficient energy supply is essential to a country. Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a country＇s energy policy. Over the years, studies have shown that a combinative model gives better projected results compared to a single model. In this study, we used Polynomial Curve and Moving Average Combination Projection （PCMACP） model to estimate the future natural gas consumption in China from 2009 to 2015. The new proposed PCMACP model shows more reliable and accurate results： its Mean Absolute Percentage Error （MAPE） is less than those of any previous models within the investigated range. According to the PCMACP model, the average annual growth rate will increase for the next 7 years and the amount of natural gas consumption will reach 171600 million cubic meters in 2015 in China.
基金supported by the National Natural Science Foundation of China (No. 51504271)
文摘Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas project(CGP)to improve the air quality in northern China.As a subcompany of China National Petroleum Corporation,PetroChina Natural Gas Marketing North Company has been focusing on natural gas resource allocation while considering numerous issues such as ensuring the bottom line of livelihood requirements in winter and the performance of economic indicators for an entire calendar year in the northern part of China.Therefore,the accurate prediction of natural gas consumption is important to PetroChina Natural Gas Marketing North Company.It has become a challenge to forecast natural gas consumption because the natural gas market has changed considerably because of the CGP.Natural gas consumption cannot be forecasted using conventional models.This study analyzes the characteristics of the CGP based on the data obtained from rural individual users and company users.Based on the analysis,the gas consumption in winter is predicted using two different forecasting approaches.The methods presented in this paper provide a basis for formulating effective measures for natural gas scheduling in the northern part of China.
文摘In recent years,China has developed rapidly in terms of natural gas.Driven by regional economic integration,a regional natural gas market composed of neighboring provinces and cities has taken shape gradually,and it tends to grow toward the same direction in policy formulation,resource coordination,facility construction and market expansion.Based on the factors such as geographical location,economic conditions and natural gas consumption,this thesis tends to conduct a horizontal comparative analysis on the economic development conditions,natural gas consumption characteristics and natural gas pipeline network density of the three regions with obvious regional integration feature in China.Then according to LMDI,four core indicators,namely economic growth effect,energy intensity effect,energy structure effect,and substitution effect are selected.The thesis is expected to explore the contribution of different indicators to the growth of natural gas consumption in these three different regions.According to the results,it can be concluded that the driving factors of natural gas consumption differ greatly among regions.Specifically speaking,the more developed the economy is,the greater the contribution of the energy substitution effect to natural gas consumption will be,and the contribution of the economic growth effect to natural gas consumption will be smaller.Despite that the contribution of energy intensity in different regions shows slight difference,the energy structure contributes the least effect,which further explains the current differences in China’s natural gas consumption characteristics and the reasons behind.
基金The paper is supported by the National Natural Science Foundation of China(NSFC)under grant No.71473155the New Star of Youth Science and Technology Plan Project in China’s Shaanxi Province with No.2016KJXX-142016 Annual Basic Scientific Research Project of Xidian University with No.JB160603.
文摘In view of the abrupt and phased features of natural gas consumption,this paper attempts to predict natural gas consumption in China with a refined forecasting approach.First,we establish a Markov switching(MS)model to identify the phase characteristics after eliminating change points in the natural gas consumption sequence,using the product partition model(PPM).The results show that there are"rapid growth"and"slow growth"regimes in the development process of natural gas consumption in China.Second,the Bayesian model average(BMA)method is employed to determine the core determinants of natural gas consumption under sub-regimes,and it is determined that there are significant differences in the influencing factors under different regimes and periods.Third,this paper establishes the BMA model of the"rapid growth"regime after predicting the state of future natural gas consumption in China.We find that,compared to some other models,the BMA model that fully recognizes the regime without considering change points has the best predictive performance.Finally,the results of static and dynamic scenario analyses show that natural gas consumption continues to rise in 2019 and has obvious seasonal charac-teristics,while possible ultra-rapid growth of consumption in the future provides a new requirement for the supply of natural gas.
基金Supported by Project of Science and Technology of PetroChina (2021DJ17,2021DJ21)。
文摘As a kind of clean energy which creates little carbon dioxide, natural gas will play a key role in the process of achieving “Peak Carbon Dioxide Emission” and “Carbon Neutrality”. The Long-range Energy Alternatives Planning System(LEAP) model was improved by using new parameters including comprehensive energy efficiency and terminal effective energy consumption. The Back Propagation(BP) Neural Network–LEAP model was proposed to predict key data such as total primary energy consumption, energy mix, carbon emissions from energy consumption, and natural gas consumption in China. Moreover, natural gas production in China was forecasted by the production composition method. Finally, based on the forecast results of natural gas supply and demand, suggestions were put forward on the development of China’s natural gas industry under the background of “Dual Carbon Targets”. The research results indicate that under the background of carbon peak and carbon neutrality, China’s primary energy consumption will peak(59.4×10^(8)tce) around 2035, carbon emissions from energy consumption will peak(103.4×10^(8)t) by 2025, and natural gas consumption will peak(6100×10^(8)m^(3)) around 2040, of which the largest increase will be contributed by the power sector and industrial sector. China’s peak natural gas production is about(2800–3400)×10^(8)m^(3), including(2100–2300)×10^(8)m^(3)conventional gas(including tight gas),(600–1050)×10^(8)m^(3)shale gas, and(150–220)×10^(8)m^(3)coalbed methane. Under the background of carbon peak and carbon neutrality, the natural gas consumption and production of China will further increase, showing a great potential of the natural gas industry.
基金Supported by the National Natural Science Foundation of China(71874133)Shaanxi Province“Special Support Program for High Level Talents”+1 种基金The Youth Innovation Team of Shaanxi UniversitiesGraduate Innovation Fund in Xidian University
文摘In view of the heterogeneity of natural gas consumption in different sectors in China,this paper utilizes Bayesian network(BN)to study the driving factors of natural gas consumption in power generation,chemical and industrial fuel sectors.Combined with Bayesian model averaging(BMA)and scenario analysis,the gas consumption of the three sectors is predicted.The results show that the expansion of urbanization will promote the gas consumption of power generation.The optimization of industrial structure and the increase of industrial gas consumption will enhance the gas consumption of chemical sector.The decrease of energy intensity and the increase of gas consumption for power generation will promote the gas consumption of industrial fuel.Moreover,the direct influencing factors of gas price are urbanization,energy structure and energy intensity.The direct influencing factors of environmental governance intensity are gas price,urbanization,industrial structure,energy intensity and energy structure.In 2025,under the high development scenario,China’s gas consumption for power generation,chemical and industrial fuel sectors will be 66.034,36.552 and 109.414 billion cubic meters respectively.From 2021 to 2025,the average annual growth rates of gas consumption of the three sectors will be 4.82%,2.18%and 4.43%respectively.
基金CRC Mining and the University of Queensland for their financial support for this study
文摘The data collected from haul truck payload management systems at various surface mines show that the payload variance is significant and must be considered in analysing the mine productivity, diesel energy consumption, greenhouse gas emissions and associated costs. The aim of this study is to determine the energy and cost saving opportunities for truck haulage operations associated with the payload variance in surface mines. The results indicate that there is a non-linear relationship between the payload variance and the fuel consumption, greenhouse gas emissions and associated costs. A correlation model, which is independent of haul road conditions, has been developed between the payload variance and the cost saving using the data from an Australian surface coal mine. The results of analysis for this particular mine show that a significant saving of fuel and greenhouse gas emissions costs is possible if the standard deviation of payload is reduced from the maximum to minimum value.
文摘The reserves, distribution, production and utilization of natural gas resources in China are introduced in this paper which leads a point of view that China＇s natural gas resources are relatively rich while distributed unevenly. The future production and consumption of China＇s natural gas are predicted using the Generalized Weng model and the Gray prediction model. The prediction suggests that with the increasing gas consumption China＇s natural gas production will not meet demand after 2010. In order to ease the supply-demand gap and realize rational development and utilization of China＇s natural gas resources, this paper puts forward some measures, such as using advanced technologies for natural gas development, establishing a long-distance pipeline network to rationalize the availability of natural gas across China and importing foreign natural gas and liquid natural gas （LNG）.
基金supported by the Fundamental Research Funds for the Central Universities(2242021k30028)the Natural Science Foundation of Jiangsu Province(BK20200991).
文摘Electrocatalysis, as a typical heterogeneous catalysis, generally occurs in the di-or tri-phase interfaces.Wettability is an important property for describing the balance of a gas-liquid-solid system. Therefore,the wettability of reaction interface, especially hydrophilicity/hydrophobicity, plays an important role in the adsorption/desorption process of gas bubbles on the surface of the solid electrode. Herein, we present a comprehensive review of the wettability control of the electrode materials applied in electrocatalysis reactions, including hydrogen evolution reaction(HER), oxygen evolution reaction(OER), oxygen reduction reaction(ORR) and carbon dioxide reduction reaction(CO_(2) RR). Firstly, the basic theories of wettability as well as the impact on electrocatalysis were introduced in this review. Secondly, the overview of modifying methods of the wettability from electrocatalyst microstructure(structural modification, surface coating, introducing hydrophilic groups) and system design(electrode, device) were suggested. At last, the deficiencies and problems in the application of wettability control are discussed,and deeper and broader application prospects are proposed.
基金the National Natural Science Foundation of China(Nos.21675007,21676015,21520102002,91622116)the National Key Research and Development Project of China(Nos.2018YFB1502401,2018YFA0702002),the Royal Society and the Newton Fund Through the Newton Advanced Fellowship Award(No.NAF/R1/191294)+2 种基金the Program for Changjiang Scholars and Innovation Research Team in the University,China(No.IRT1205)Fundamental Research Funds for the Central Universities of Chinathe Long-term Subsidy Mechanism from the Ministry of Finance and the Ministry of Education of China。
文摘Electrochemical oxygen reduction reaction(ORR)is crucial for fuel cells and metal-air batteries,while the oxygen consumption dynamics study during ORR,which affects the ORR efficiency,is not as concerned as catalysts design does.Herein the consumption behavior of an individual oxygen bubble on Pt foils with different wettabilities during ORR was tracked by a real-time approach to reveal whether the surface wettability of electrode can influence the consumption dynamics and determine the reaction reactive zones of oxygen bubble consumption.The oxygen bubble underwent a "constant contact angle"dominant consumption model on aerophobic Pt foil,while an initial "constant radius"and the subsequent"constant contact angle"oxygen consumption models were observed on aero philic Pt foil.Results here demonstrated that the current was proportional to the bottom contact area,rather than the three-phase contact line of the bubbles according to the fitting curves between individual bubble current and the consumption behavior parameters.This study highlights the important role of the gas-solid interface in influencing the efficiency of gas consumption electrochemical reactions,which shall benefit the understanding of reaction kinetics and the rational design of electrocatalysts.
基金supported by the National Key Technologies R&D Program of China(Grant No.2011BAE04B02)Key Technologies R&D Program of Beijing(Grant No.Z161100000716002)
文摘Top gas recycling oxygen blast furnace（TGR-OBF）process is a promising ironmaking process.The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume（per ton hot metal）,which once led to hanging-up and shutdowns in practice of the Toulachermet.In order to avoid this weakness,the strategy of medium oxygen blast furnace was presented.The maneuverable zone of the TGR-OBF was determined by the top gas volume,which should not be far from the data of the traditional blast furnace.The deviation of ±12.5% was used,and then the maneuverable blast oxygen content is from 0.30 to 0.47 according to the calculation.The flame temperature and the top gas volume have no much difference compared to those of the traditional blast furnace.The minimum carbon consumption of 357 kg per ton hot metal in the maneuverable zone occurs at the oxygen content of 0.30（fuel saving of 14%）.In the unsteady evolution,the N2 accumulation could approach nearly zero after the recycling reached 6 times.Thus far,some TGR-OBF industrial trials have been carried out in different countries,but the method of medium oxygen enriched TGR-OBF has not been implemented,because the accumulation of N2 was worried about.The presented strategy of medium oxygen enriched TGR-OBF is applicable and the strategy with good operational performance is strongly suggested as a forerunner of the full oxygen blast furnace.
基金Supported by National Natural Science Foundation of China(11401418)。
文摘The conventional grey GM(2,1)model built for the fast growing time sequence generally has big errors.To improve the modeling precision,the paper improves from the following two aspects:First,the paper transforms the accumulated generating sequence of original time sequence quantitatively to make the transformed time sequence have the better adaptability to the model;second,the paper extends the conventional grey GM(2,1)model’s structure to make the extended model meet the variation law of fast growing sequence better.The extended grey model is called the GM(2,1,Σexp(ct))model.The paper offers the parameter optimization method and the solving method of time response sequence of GM(2,1,Σexp(ct))model.Using the model and methods proposed,the paper builds the GM(2,1,Σexp(ct))models for the natural gas consumption of China and Chongqing City,China,respectively.Results show that the models built have high simulation precision and prediction precision.
基金The authors wish to thank the financial support received from various sources for conducting this researchThis work was supported by the Key Research and Development Program of Shaanxi(No.2020NY-204)the Fundamental Research Funds for the Central Universities,CHD(No.300102289103).
文摘To improve the prediction accuracy of heating demand, an appropriate base temperature should be estimated before using the heating degree-days (HDD) approach. This study collected the measured data for gas consumption at half-hourly resolution and the building physical characteristics from 89 educational buildings over four years. To determine the base temperature, in addition to the ambient temperature, more detailed independent variables, i.e. solar insolation, relative humidity, wind speed, and one-day ahead residual temperature, were incorporated into a three-parameter change-point multi-variable regression (3PH-MVR) for heating. The mean base temperature using the 3PH-MVR approach was about 0.4℃ lower than the results from the 3PH method only. The relationships between base temperature and annual HDD (based on 15.5℃), building location, and mean daily solar insolation were evaluated. It is found that the annual HDD and the daily insolation had clear impacts on base temperature, while there was a plausible relationship between base temperature and building location. Compared with traditional approach, the proposed 3PH-MVR method considers multiple weather parameters and determines a more robust base temperature, thus improving the prediction accuracy of HDD with higher average R2 value at 0.86 than that of univariate regression (0.82).
