The composition and sedimentary controlling effect of the coal measure gas-bearing(CMG)system of the Jurassic Xishanyao Formation in the southern margin of the Junggar Basin(SJB)are analysed based on core observations...The composition and sedimentary controlling effect of the coal measure gas-bearing(CMG)system of the Jurassic Xishanyao Formation in the southern margin of the Junggar Basin(SJB)are analysed based on core observations,sample tests,and logging data.The results show that the lithological associations of the SJB can be classified into 6 types based on sediment supply strengths and sealing abilities,while the gas shows of CMG reservoirs vary greatly among different lithological associations.Due to the diversified coal-forming environment and multistage coal accumulation,superimposed CMG systems are generally developed in the SJB,and their types include:superimposed unattached CMG systems,multilayer unified CMG systems,and superimposed mixed CMG systems.Furthermore,sedimentary controls on the vertical and regional distributions of different types of CMG systems are discussed according to the sedimentary facies of single wells and well cross-sections and the corresponding data of well log,gas logging,and gas contents.Shore shallow lake environments in the Fukang,Miquan,and northern Liuhuanggou areas were favourable for forming superimposed unattached CMG systems.Braided river environments in the Houxia and the southern Liuhuanggou areas usually formed multilayer unified CMG systems.Braided river delta environments in the Manasi,Hutubi,and eastern Sikeshu areas generally developed multilayer unified CMG systems and superimposed mixed CMG systems.For different types of superimposed CMG systems,the number of gas-bearing units,coal seam gas content,vertical hydraulic connectivity and lateral continuity vary considerably,which makes it necessary to tailor the CMG co-production plan to the type of CMG system.展开更多
Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe t...Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe the causal relationships among the decision objective and the variables of the scheduling process for the industrial system, based on which the total scheduling amount of the BFG system can be computed by using a causal fuzzy C-means(CFCM) clustering algorithm. In this algorithm,not only the distances among the historical samples but also the effects of different solutions on the gas tank level are considered.The scheduling solution can be determined based on the proposed causal probability of the causality diagram calculated by the total amount and the conditions of the adjustable units. The causal probability quantifies the impact of different allocation schemes of the total scheduling amount on the BFG system. An evaluation method is then proposed to evaluate the effectiveness of the scheduling solutions. The experiments by using the practical data coming from a steel plant in China indicate that the proposed approach can effectively improve the scheduling accuracy and reduce the gas diffusion.展开更多
Natural gas hydrate,oil and gas were all found together in the Qilian Mountain permafrost area,northeast of Qinghai-Tibet Plateau,China.They are closely associated with each other in space,but whether they are in any ...Natural gas hydrate,oil and gas were all found together in the Qilian Mountain permafrost area,northeast of Qinghai-Tibet Plateau,China.They are closely associated with each other in space,but whether they are in any genetic relations are unknown yet.In this paper,a hydrocarbon gas-generation series,gas-fluid migration series and hydrocarbon gas-accumulation series are analyzed to probe the spatial,temporal and genetic relationships among natural natural gas hydrate,oil and gas.The subsequent results show that natural gas hydrate,oil and gas actually form a natural gas hydrate-oil-gas system.Based on the Middle Jurassic and the Upper Triassic hydrocarbon gas-generation series,it is divided into four major sub-systems in the study area:(1)A conventional Upper Triassic gas-bearing sub-system with peak hydrocarbon gas-generation in the late Middle Jurassic;(2)a conventional Middle Jurassic oil-bearing sub-system with low to mature hydrocarbon gas-generation in the late Middle Jurassic;(3)a natural gas hydrate sub-system with main gas source from the Upper Triassic gas-bearing sub-system and minor gas source from the Middle Jurassic oil-bearing sub-system as well as little gas source from the Middle Jurassic coal-bed gas and the microbial gas;(4)a shallower gas sub-system with microbial alteration of the main gas source from the Upper Triassic gas-bearing sub-system.This natural gas hydrate-oil-gas system and its sub-systems are not only theoretical but also practical,and thus they will play an important role in the further exploration of natural gas hydrate,oil and gas,even other energy resources in the study area.展开更多
The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric a...The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric and natural gas systems,it is critical to enhance the load restoration capability of both systems.This paper proposes a coordinated optimization strategy for resilience-enhanced RIENGS load restoration and repair scheduling and transforms it into a mixed integer second-order cone programming(MISOCP)model.The proposed model considers the distribution network reconfiguration and the coordinated repair strategy between the two systems,minimizing the total system load loss cost and repair time.In addition,a bi-directional gas flow model is used to describe the natural gas system,which can provide the RIENGS with more flexibility for load restoration during natural gas system failure.Finally,the effectiveness of the proposed approach is verified by conducting case studies on the test systems RIENGS E13-G7 and RIENGS E123-G20.展开更多
Green hydrogen can be produced by consuming surplus renewable generations.It can be injected into the natural gas networks,accelerating the decarbonization of energy systems.However,with the fluctuation of renewable e...Green hydrogen can be produced by consuming surplus renewable generations.It can be injected into the natural gas networks,accelerating the decarbonization of energy systems.However,with the fluctuation of renewable energies,the gas composition in the gas network may change dramatically as the hydrogen injection fluctuates.The gas interchangeability may be adversely affected.To investigate the ability to defend the fluctuated hydrogen injection,this paper proposes a gas interchangeability resilience evaluation method for hydrogen-blended integrated electricity and gas systems(H-IEGS).First,gas interchangeability resilience is defined by proposing several novel metrics.Then,A two-stage gas interchangeability management scheme is proposed to accommodate the hydrogen injections.The steady-state optimal electricity and hydrogen-gas energy flow technique is performed first to obtain the desired operating state of the H-IEGS.Then,the dynamic gas composition tracking is implemented to calculate the real-time traveling of hydrogen contents in the gas network,and evaluate the time-varying gas interchangeability metrics.Moreover,to improve the computation efficiency,a self-adaptive linearization technique is proposed and embedded in the solution process of discretized partial derivative equations.Finally,an IEEE 24 bus reliability test system and Belgium natural gas system are used to validate the proposed method.展开更多
Considerable energy is consumed during steel manufacturing process. Byproduct gas emerges as secondary energy in the process; however, it is also an atmospheric pollution source if it is released into the air. Therefo...Considerable energy is consumed during steel manufacturing process. Byproduct gas emerges as secondary energy in the process; however, it is also an atmospheric pollution source if it is released into the air. Therefore, the optimal utilization of byproduct gas not only saves energy but also protects environment. To solve this issue, a fore- cast model of gas supply, gas demand and surplus gas in a steel plant was proposed. With the progress of energy conservation, the amount of surplus gas was very large. In a steel plant, the surplus gas was usually sent to boilers to generate steam. However, each boiler had an individual efficiency. So the optimization of the utilization of surplus gas in boilers was a key topic. A dynamic programming method was used to develop an optimal utilization strategy for surplus gas. Finally, a case study providing a sound confirmation was given.展开更多
A mathematical model was proposed to optimize byproduct gas system and reduce the total cost. The scope and boundaries of the system were also discussed at the same time. Boilers and gasholders were buffer users to so...A mathematical model was proposed to optimize byproduct gas system and reduce the total cost. The scope and boundaries of the system were also discussed at the same time. Boilers and gasholders were buffer users to solve the fluctuation of byproduct gases. The priority of gasholders should be ranked the last. The allocation of surplus ga- ses among gasholders and boilers was also discussed to make full use of gases and realize zero emission targets. Case study shows that the proposed model made good use of byproduct gases and at least 7.8 ~//00 operation cost was re- duced, compared with real data in iron and steel industry.展开更多
Upper Paleozoic coal measures in the Ordos Basin consist of dark mudstone and coal beds and are important source rocks for gas generation. Gas accumulations include coal-bed methane （CBM）, tight gas and conventional...Upper Paleozoic coal measures in the Ordos Basin consist of dark mudstone and coal beds and are important source rocks for gas generation. Gas accumulations include coal-bed methane （CBM）, tight gas and conventional gas in different structural areas. CBM accumulations are mainly distributed in the marginal area of the Ordos Basin, and are estimated at 3.5 × 1012 m3. Tight gas accumulations exist in the middle part of the Yishan Slope area, previously regarded as the basin-centered gas system and now considered as stratigraphic lithologic gas reservoirs. This paper reviews the characteristics of tight gas accumulations： poor physical properties （porosity 〈 8%, permeability 〈 0.85 × 10 3 μm2）, abnormal pressure and the absence of well-defined gas water contacts. CBM is a self-generation and self- reservoir, while gas derived from coal measures migrates only for a short distance to accumulate in a tight reservoir and is termed near-generation and near-reservoir. Both CBM and tight gas systems require source rocks with a strong gas generation ability that extends together over wide area. However, the producing area of the two systems may be significantly different.展开更多
A new thermodynamic model for gas hydrates was established by combining the modified Patel-Teja equation of state proposed for aqueous electrolyte systems and the simplified Holder -John multi -shell hydrate model. Th...A new thermodynamic model for gas hydrates was established by combining the modified Patel-Teja equation of state proposed for aqueous electrolyte systems and the simplified Holder -John multi -shell hydrate model. The new hydrate model is capable of predicting the hydrate formation/dissociation conditions of natural gas systems containing pure water/formation water (brine) and polar inhibitor without using activity coefficient model. Extensive test results indicate very encouraging results.展开更多
A parametric study of the clustering transition of a vibration-driven granular gas system is performed by simulation.The parameters studied include the global volume fraction of the system,the size of the system,the f...A parametric study of the clustering transition of a vibration-driven granular gas system is performed by simulation.The parameters studied include the global volume fraction of the system,the size of the system,the friction coefficient,and the restitution coefficient among particles and among particle-walls.The periodic boundary and fixed boundary of sidewalls are also checked in the simulation.The simulation results provide us the necessary“heating”time for the system to reach steady state,and the friction term needed to be included in the“cooling”time.A gas-cluster phase diagram obtained through Kolmogorov-Smirnov(K-S)test analysis using similar experimental parameters is given.The influence of the parameters to the transition is then investigated in simulations.This simulation investigation helps us gain understanding which otherwise cannot be obtained by experiment alone,and makes suggestions on the determination of parameters to be chosen in experiments.展开更多
To make full use of the gas resource, stabilize the pipe network pressure, and obtain higher economic benefits in the iron and steel industry, the surplus gas prediction and scheduling models were proposed. Before app...To make full use of the gas resource, stabilize the pipe network pressure, and obtain higher economic benefits in the iron and steel industry, the surplus gas prediction and scheduling models were proposed. Before applying the forecasting techniques, a support vector classifier was first used to classify the data, and then the filtering was used to create separate trend and volatility sequences. After forecasting, the Markov chain transition probability matrix was introduced to adjust the residual. Simulation results using surplus gas data from an iron and steel enterprise demonstrate that the constructed SVC-HP-ENN-LSSVM-MC prediction model prediction is accurate, and that the classification accuracy is high under different conditions. Based on this, the scheduling model was constructed for surplus gas operating, and it has been used to investigate the comprehensive measures for managing the operational probabilistic risk and optimize the economic benefit at various working conditions and implementations. It has extended the concepts of traditional surplus gas dispatching systems, and provides a method for enterprises to determine optimal schedules.展开更多
The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ...The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.展开更多
International oil keeps low-price running after crash, and China deepens reformm domestically. Using this opportunity, China lays the same emphasis on investment and trade, on onshore and offshore transportation, give...International oil keeps low-price running after crash, and China deepens reformm domestically. Using this opportunity, China lays the same emphasis on investment and trade, on onshore and offshore transportation, gives full play to the important role of market in resource distribution, speeds up oil and gas system reform to guarantee clean, e fficienL safe and steady energy supply and long-term demand for energy. We systematically and thoroughly established legal system for oil and gas domains, reformed management system for energy domain, re＆treed regulatory domain, built modern market entity and multi-level market system, and improved oil and gas pricing mechanism, etc.展开更多
For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system...For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.展开更多
With the increasing share of uncertain renewable energy generation and natural gas-fired power production in power systems,a deep integration between power and natural gas systems is highly desirable.We develop a thre...With the increasing share of uncertain renewable energy generation and natural gas-fired power production in power systems,a deep integration between power and natural gas systems is highly desirable.We develop a three-stage coordinated operation model for two coupled systems,using stochastic programming to adapt to the uncertainty of wind power production.Compared with the conventional two-stage model,we introduce the intra-day-stage operation and obtain a more flexible adjustment.The natural gas system operation is a single stage(i.e.,day-ahead scheduling),which is consistent with current practice.The fluctuation in gas demand associated with power generation caused by the intermittent wind power production at the intra-day and real-time operation is balanced by the line pack.Numerical results of two test systems verify the superiority of the proposed model over the two-stage model.展开更多
Coordinated operation of power,heating,and gas systems in an integrated energy system(IES)can effectively improve the energy systems'economy,safety,and reliability.However,the natural gas system is dynamic and is ...Coordinated operation of power,heating,and gas systems in an integrated energy system(IES)can effectively improve the energy systems'economy,safety,and reliability.However,the natural gas system is dynamic and is modeled by complex nonconvex constraints,which makes the natural gas system dispatch model difficult to solve effectively.This poses a serious challenge to the optimal dispatch of the IES with a natural gas system.Inspired by a recent novel rank minimization algorithm(NRMA),this paper proposes a modified rank minimization algorithm(MRMA),which overcomes the infeasibility issue of the NRMA and can efficiently solve the dynamic natural gas system(DNGS)dispatch problem.Moreover,binary search and acceleration approaches are proposed to improve the MRMA's computational efficiency,surpassing the NRMA and the conventional interior point method.Numerical tests demonstrate that MRMA can solve DNGS dispatch problems much more efficiently than conventional methods.展开更多
Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of ...Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of MOC, in the context of lEGS's optimal scheduling. Specifically, the proposed method enables flexible temporal step sizes without sacrificing accuracy, significantly reducing non-convergence due to numerical oscillations. The effectiveness of the proposed method is validated through case studies in different simulation settings.展开更多
The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic en...The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic energy flow(PEF)analysis is usually conducted to assess the operating status of the IEGS by calculating the probability distribution of state variables(e.g.,gas pressure,gas flow,voltage,and power flow).However,multiform time-variant uncertainties can simultaneously reside in the IEGS,including discrete(e.g.,the component failure or functioning)and continuous ones(e.g.,renewable energy outputs).Existing PEF analysis works cannot completely deal with time-variant multiform uncertainties featured with different mathematical characteristics.This limitation hinders the estimation of potential operating risks of the IEGS.To address this,this paper proposes a generalized framework for analyzing the probabilistic energy flow of the IEGS considering multiform uncertainties.Firstly,both time-varying random working states and variable outputs of components are represented as probabilistic models utilizing the L_(z)-transform technique.The probabilistic model is composed of some representative states depicting possible realizations of the component's performance and corresponding probabilities.On this basis,the optimal energy flow(OEF)operator is defined to aggregate probabilistic models of different components to determine probabilistic models of energy flows in the IEGS.Furthermore,multidimensional indices are constructed to comprehensively explore the probabilistic features of energy flows and the impact of probabilistic energy flows on the system performance.In this paper,the system performance mainly refers to the energy-serving capability of the IEGS.Specifically,probabilistic distribution characteristics of energy flows are explicitly displayed by relevant expectations,standard deviations as well as skewnesses.Indices such as the nodal expected gas and electricity not supplied are adopted to evaluate the influence of the probabilistic energy flow on the system performance.Numerical studies reveal that energy flows through different pipelines or power lines present diversified statistical characteristics,which indicates that they are influenced by multiform uncertainties to different extents.展开更多
Large renewable penetration has been witnessed in power systems, resulting in reduced level of system inertia and increasing requirements for frequency response services. There have been plenty of studies developing f...Large renewable penetration has been witnessed in power systems, resulting in reduced level of system inertia and increasing requirements for frequency response services. There have been plenty of studies developing frequency-constrained operation models for power system security. However, most existing literature only focuses on operational level rather than planning level. To fill this gap, this paper proposes a novel planning model for the optimal sizing problem of integrated power and gas systems, capturing both under and over frequency security requirements. A detailed unit commitment setup considering different ramping rates is incorporated into the planning model to accurately represent the scheduling behavior of each individual generator and accurate inertia calculation. The power importing and exporting behaviors of interconnectors are considered, which can influence the largest loss of generation and demand, accounting for under and over frequency security, respectively. Additionally, a deep learning-based clustering method featured by concurrent and integrated learning is introduced in the planning model to effectively generate representative days. Case studies have been conducted on a coupled 6-bus power and 7-node gas system as well as a 14-bus power and 14-node gas system to verify the effectiveness of the proposed planning model in accurate clustering performance and realistic investment decision making.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.41772132,41502157,41530314)the key project of the National Science&Technology(No.2016ZX05043-001)+1 种基金the Fundamental Research Funds for the Central Universities(No.2652019095)the China Postdoctoral Science Foundation(No.2021M692998)。
文摘The composition and sedimentary controlling effect of the coal measure gas-bearing(CMG)system of the Jurassic Xishanyao Formation in the southern margin of the Junggar Basin(SJB)are analysed based on core observations,sample tests,and logging data.The results show that the lithological associations of the SJB can be classified into 6 types based on sediment supply strengths and sealing abilities,while the gas shows of CMG reservoirs vary greatly among different lithological associations.Due to the diversified coal-forming environment and multistage coal accumulation,superimposed CMG systems are generally developed in the SJB,and their types include:superimposed unattached CMG systems,multilayer unified CMG systems,and superimposed mixed CMG systems.Furthermore,sedimentary controls on the vertical and regional distributions of different types of CMG systems are discussed according to the sedimentary facies of single wells and well cross-sections and the corresponding data of well log,gas logging,and gas contents.Shore shallow lake environments in the Fukang,Miquan,and northern Liuhuanggou areas were favourable for forming superimposed unattached CMG systems.Braided river environments in the Houxia and the southern Liuhuanggou areas usually formed multilayer unified CMG systems.Braided river delta environments in the Manasi,Hutubi,and eastern Sikeshu areas generally developed multilayer unified CMG systems and superimposed mixed CMG systems.For different types of superimposed CMG systems,the number of gas-bearing units,coal seam gas content,vertical hydraulic connectivity and lateral continuity vary considerably,which makes it necessary to tailor the CMG co-production plan to the type of CMG system.
基金supported by the National Natural Sciences Foundation of China(61473056,61533005,61522304,61603068,U1560102)
文摘Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe the causal relationships among the decision objective and the variables of the scheduling process for the industrial system, based on which the total scheduling amount of the BFG system can be computed by using a causal fuzzy C-means(CFCM) clustering algorithm. In this algorithm,not only the distances among the historical samples but also the effects of different solutions on the gas tank level are considered.The scheduling solution can be determined based on the proposed causal probability of the causality diagram calculated by the total amount and the conditions of the adjustable units. The causal probability quantifies the impact of different allocation schemes of the total scheduling amount on the BFG system. An evaluation method is then proposed to evaluate the effectiveness of the scheduling solutions. The experiments by using the practical data coming from a steel plant in China indicate that the proposed approach can effectively improve the scheduling accuracy and reduce the gas diffusion.
基金This work was supported by the projects of China Geological Survey(DD20160223,DD20190102).
文摘Natural gas hydrate,oil and gas were all found together in the Qilian Mountain permafrost area,northeast of Qinghai-Tibet Plateau,China.They are closely associated with each other in space,but whether they are in any genetic relations are unknown yet.In this paper,a hydrocarbon gas-generation series,gas-fluid migration series and hydrocarbon gas-accumulation series are analyzed to probe the spatial,temporal and genetic relationships among natural natural gas hydrate,oil and gas.The subsequent results show that natural gas hydrate,oil and gas actually form a natural gas hydrate-oil-gas system.Based on the Middle Jurassic and the Upper Triassic hydrocarbon gas-generation series,it is divided into four major sub-systems in the study area:(1)A conventional Upper Triassic gas-bearing sub-system with peak hydrocarbon gas-generation in the late Middle Jurassic;(2)a conventional Middle Jurassic oil-bearing sub-system with low to mature hydrocarbon gas-generation in the late Middle Jurassic;(3)a natural gas hydrate sub-system with main gas source from the Upper Triassic gas-bearing sub-system and minor gas source from the Middle Jurassic oil-bearing sub-system as well as little gas source from the Middle Jurassic coal-bed gas and the microbial gas;(4)a shallower gas sub-system with microbial alteration of the main gas source from the Upper Triassic gas-bearing sub-system.This natural gas hydrate-oil-gas system and its sub-systems are not only theoretical but also practical,and thus they will play an important role in the further exploration of natural gas hydrate,oil and gas,even other energy resources in the study area.
基金funded by the Science and Technology Project of State Grid Jilin Electric Power Co.,Ltd.(Project Name:Research onDistributionNetworkResilience Assessment and Improvement Technology for Natural Disaster Areas).
文摘The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric and natural gas systems,it is critical to enhance the load restoration capability of both systems.This paper proposes a coordinated optimization strategy for resilience-enhanced RIENGS load restoration and repair scheduling and transforms it into a mixed integer second-order cone programming(MISOCP)model.The proposed model considers the distribution network reconfiguration and the coordinated repair strategy between the two systems,minimizing the total system load loss cost and repair time.In addition,a bi-directional gas flow model is used to describe the natural gas system,which can provide the RIENGS with more flexibility for load restoration during natural gas system failure.Finally,the effectiveness of the proposed approach is verified by conducting case studies on the test systems RIENGS E13-G7 and RIENGS E123-G20.
基金supported in part by the Science and Technology Development Fund,Macao SAR(File no.SKL-IOTSC(UM)-2021-2023,File no.0003/2020/AKP,and File no.0117/2022/A3)the Natural Science Foundation of Jiangsu Province,China(Operational reliability evaluation of multi-source and heterogeneous urban multi-energy systems,BK20220261).
文摘Green hydrogen can be produced by consuming surplus renewable generations.It can be injected into the natural gas networks,accelerating the decarbonization of energy systems.However,with the fluctuation of renewable energies,the gas composition in the gas network may change dramatically as the hydrogen injection fluctuates.The gas interchangeability may be adversely affected.To investigate the ability to defend the fluctuated hydrogen injection,this paper proposes a gas interchangeability resilience evaluation method for hydrogen-blended integrated electricity and gas systems(H-IEGS).First,gas interchangeability resilience is defined by proposing several novel metrics.Then,A two-stage gas interchangeability management scheme is proposed to accommodate the hydrogen injections.The steady-state optimal electricity and hydrogen-gas energy flow technique is performed first to obtain the desired operating state of the H-IEGS.Then,the dynamic gas composition tracking is implemented to calculate the real-time traveling of hydrogen contents in the gas network,and evaluate the time-varying gas interchangeability metrics.Moreover,to improve the computation efficiency,a self-adaptive linearization technique is proposed and embedded in the solution process of discretized partial derivative equations.Finally,an IEEE 24 bus reliability test system and Belgium natural gas system are used to validate the proposed method.
基金Sponsored by Science and Technology Research Funds of Liaoning Provincial Education Department of China(L2012082)
文摘Considerable energy is consumed during steel manufacturing process. Byproduct gas emerges as secondary energy in the process; however, it is also an atmospheric pollution source if it is released into the air. Therefore, the optimal utilization of byproduct gas not only saves energy but also protects environment. To solve this issue, a fore- cast model of gas supply, gas demand and surplus gas in a steel plant was proposed. With the progress of energy conservation, the amount of surplus gas was very large. In a steel plant, the surplus gas was usually sent to boilers to generate steam. However, each boiler had an individual efficiency. So the optimization of the utilization of surplus gas in boilers was a key topic. A dynamic programming method was used to develop an optimal utilization strategy for surplus gas. Finally, a case study providing a sound confirmation was given.
基金Item Sponsored by the Fundamental Research Funds for the Central Universities of China(N140203002)
文摘A mathematical model was proposed to optimize byproduct gas system and reduce the total cost. The scope and boundaries of the system were also discussed at the same time. Boilers and gasholders were buffer users to solve the fluctuation of byproduct gases. The priority of gasholders should be ranked the last. The allocation of surplus ga- ses among gasholders and boilers was also discussed to make full use of gases and realize zero emission targets. Case study shows that the proposed model made good use of byproduct gases and at least 7.8 ~//00 operation cost was re- duced, compared with real data in iron and steel industry.
基金supported by the National Natural Science Foundation of China(Grant No.41102088)the Fundamental Research Funds for the Central Universities(Grant No.2010ZY03)the open research program of the Geological Processes and Mineral Resources(GPMR),China University of Geosciences,Beijing (Grant No.GPMR201030)
文摘Upper Paleozoic coal measures in the Ordos Basin consist of dark mudstone and coal beds and are important source rocks for gas generation. Gas accumulations include coal-bed methane （CBM）, tight gas and conventional gas in different structural areas. CBM accumulations are mainly distributed in the marginal area of the Ordos Basin, and are estimated at 3.5 × 1012 m3. Tight gas accumulations exist in the middle part of the Yishan Slope area, previously regarded as the basin-centered gas system and now considered as stratigraphic lithologic gas reservoirs. This paper reviews the characteristics of tight gas accumulations： poor physical properties （porosity 〈 8%, permeability 〈 0.85 × 10 3 μm2）, abnormal pressure and the absence of well-defined gas water contacts. CBM is a self-generation and self- reservoir, while gas derived from coal measures migrates only for a short distance to accumulate in a tight reservoir and is termed near-generation and near-reservoir. Both CBM and tight gas systems require source rocks with a strong gas generation ability that extends together over wide area. However, the producing area of the two systems may be significantly different.
文摘A new thermodynamic model for gas hydrates was established by combining the modified Patel-Teja equation of state proposed for aqueous electrolyte systems and the simplified Holder -John multi -shell hydrate model. The new hydrate model is capable of predicting the hydrate formation/dissociation conditions of natural gas systems containing pure water/formation water (brine) and polar inhibitor without using activity coefficient model. Extensive test results indicate very encouraging results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1738120,11474326,and 11705256)Young Scholar of CAS”Light of West China”Program for Guanghui Yang(Grant No.2018-98)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA21010202)the International Cooperation Project of China Manned Space Program.
文摘A parametric study of the clustering transition of a vibration-driven granular gas system is performed by simulation.The parameters studied include the global volume fraction of the system,the size of the system,the friction coefficient,and the restitution coefficient among particles and among particle-walls.The periodic boundary and fixed boundary of sidewalls are also checked in the simulation.The simulation results provide us the necessary“heating”time for the system to reach steady state,and the friction term needed to be included in the“cooling”time.A gas-cluster phase diagram obtained through Kolmogorov-Smirnov(K-S)test analysis using similar experimental parameters is given.The influence of the parameters to the transition is then investigated in simulations.This simulation investigation helps us gain understanding which otherwise cannot be obtained by experiment alone,and makes suggestions on the determination of parameters to be chosen in experiments.
基金Project(51204082)supported by the National Natural Science Foundation of ChinaProject(KKSY201458118)supported by the Talent Cultivation Project of Kuning University of Science and Technology,China
文摘To make full use of the gas resource, stabilize the pipe network pressure, and obtain higher economic benefits in the iron and steel industry, the surplus gas prediction and scheduling models were proposed. Before applying the forecasting techniques, a support vector classifier was first used to classify the data, and then the filtering was used to create separate trend and volatility sequences. After forecasting, the Markov chain transition probability matrix was introduced to adjust the residual. Simulation results using surplus gas data from an iron and steel enterprise demonstrate that the constructed SVC-HP-ENN-LSSVM-MC prediction model prediction is accurate, and that the classification accuracy is high under different conditions. Based on this, the scheduling model was constructed for surplus gas operating, and it has been used to investigate the comprehensive measures for managing the operational probabilistic risk and optimize the economic benefit at various working conditions and implementations. It has extended the concepts of traditional surplus gas dispatching systems, and provides a method for enterprises to determine optimal schedules.
文摘The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.
文摘International oil keeps low-price running after crash, and China deepens reformm domestically. Using this opportunity, China lays the same emphasis on investment and trade, on onshore and offshore transportation, gives full play to the important role of market in resource distribution, speeds up oil and gas system reform to guarantee clean, e fficienL safe and steady energy supply and long-term demand for energy. We systematically and thoroughly established legal system for oil and gas domains, reformed management system for energy domain, re＆treed regulatory domain, built modern market entity and multi-level market system, and improved oil and gas pricing mechanism, etc.
基金Supported by the NSFC-Industry Joint Fund for Innovative Development(U24B2016)China National Science and Technology Major Project(2025ZD1402700)。
文摘For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.
基金supported partially by National Natural Science Foundation of China under Grant 51877071 and 52007051。
文摘With the increasing share of uncertain renewable energy generation and natural gas-fired power production in power systems,a deep integration between power and natural gas systems is highly desirable.We develop a three-stage coordinated operation model for two coupled systems,using stochastic programming to adapt to the uncertainty of wind power production.Compared with the conventional two-stage model,we introduce the intra-day-stage operation and obtain a more flexible adjustment.The natural gas system operation is a single stage(i.e.,day-ahead scheduling),which is consistent with current practice.The fluctuation in gas demand associated with power generation caused by the intermittent wind power production at the intra-day and real-time operation is balanced by the line pack.Numerical results of two test systems verify the superiority of the proposed model over the two-stage model.
基金supported by National Natural Science Foundation of China(52377107,52007105)the Taishan Scholars Program。
文摘Coordinated operation of power,heating,and gas systems in an integrated energy system(IES)can effectively improve the energy systems'economy,safety,and reliability.However,the natural gas system is dynamic and is modeled by complex nonconvex constraints,which makes the natural gas system dispatch model difficult to solve effectively.This poses a serious challenge to the optimal dispatch of the IES with a natural gas system.Inspired by a recent novel rank minimization algorithm(NRMA),this paper proposes a modified rank minimization algorithm(MRMA),which overcomes the infeasibility issue of the NRMA and can efficiently solve the dynamic natural gas system(DNGS)dispatch problem.Moreover,binary search and acceleration approaches are proposed to improve the MRMA's computational efficiency,surpassing the NRMA and the conventional interior point method.Numerical tests demonstrate that MRMA can solve DNGS dispatch problems much more efficiently than conventional methods.
文摘Though an accurate discretization approach for gas flow dynamics, the method of characteristics (MOC) is liable to instability for inappropriate step sizes. This letter addresses the numerical stability limitation of MOC, in the context of lEGS's optimal scheduling. Specifically, the proposed method enables flexible temporal step sizes without sacrificing accuracy, significantly reducing non-convergence due to numerical oscillations. The effectiveness of the proposed method is validated through case studies in different simulation settings.
基金supported by the Science and Technology Project of State Grid Corporation of China(5108-202218280A-2-448-XG).
文摘The coupling of electricity and gas systems has been ever-augmented with the wide deployment of gas-fired generators,which facilitates the conception of the integrated electricity and gas system(IEGS).Probabilistic energy flow(PEF)analysis is usually conducted to assess the operating status of the IEGS by calculating the probability distribution of state variables(e.g.,gas pressure,gas flow,voltage,and power flow).However,multiform time-variant uncertainties can simultaneously reside in the IEGS,including discrete(e.g.,the component failure or functioning)and continuous ones(e.g.,renewable energy outputs).Existing PEF analysis works cannot completely deal with time-variant multiform uncertainties featured with different mathematical characteristics.This limitation hinders the estimation of potential operating risks of the IEGS.To address this,this paper proposes a generalized framework for analyzing the probabilistic energy flow of the IEGS considering multiform uncertainties.Firstly,both time-varying random working states and variable outputs of components are represented as probabilistic models utilizing the L_(z)-transform technique.The probabilistic model is composed of some representative states depicting possible realizations of the component's performance and corresponding probabilities.On this basis,the optimal energy flow(OEF)operator is defined to aggregate probabilistic models of different components to determine probabilistic models of energy flows in the IEGS.Furthermore,multidimensional indices are constructed to comprehensively explore the probabilistic features of energy flows and the impact of probabilistic energy flows on the system performance.In this paper,the system performance mainly refers to the energy-serving capability of the IEGS.Specifically,probabilistic distribution characteristics of energy flows are explicitly displayed by relevant expectations,standard deviations as well as skewnesses.Indices such as the nodal expected gas and electricity not supplied are adopted to evaluate the influence of the probabilistic energy flow on the system performance.Numerical studies reveal that energy flows through different pipelines or power lines present diversified statistical characteristics,which indicates that they are influenced by multiform uncertainties to different extents.
基金supported by the National Grid ESO Project‘Tool for Co-Optimisation of Energy and Frequency-Containment Services(COEF)’.
文摘Large renewable penetration has been witnessed in power systems, resulting in reduced level of system inertia and increasing requirements for frequency response services. There have been plenty of studies developing frequency-constrained operation models for power system security. However, most existing literature only focuses on operational level rather than planning level. To fill this gap, this paper proposes a novel planning model for the optimal sizing problem of integrated power and gas systems, capturing both under and over frequency security requirements. A detailed unit commitment setup considering different ramping rates is incorporated into the planning model to accurately represent the scheduling behavior of each individual generator and accurate inertia calculation. The power importing and exporting behaviors of interconnectors are considered, which can influence the largest loss of generation and demand, accounting for under and over frequency security, respectively. Additionally, a deep learning-based clustering method featured by concurrent and integrated learning is introduced in the planning model to effectively generate representative days. Case studies have been conducted on a coupled 6-bus power and 7-node gas system as well as a 14-bus power and 14-node gas system to verify the effectiveness of the proposed planning model in accurate clustering performance and realistic investment decision making.
