This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dyn...This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dynamics model of sewage treatment facility expansion.Elaborating on detection technology,construction of an intelligent operation and maintenance system,and factors to be considered for sewage plant expansion,it emphasizes the importance of collaborative development and verifies benefits through the PSR model.展开更多
The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural ...The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural gas pipeline network requires more strictly on the calculation efficiency of transient simulation.To this end,this paper proposes a new method for the transient simulation of natural gas pipeline networks based on fracture-dimension-reduction algorithm.Firstly,a pipeline network model is abstracted into a station model,inter-station pipeline network model and connection node model.Secondlly,the pressure at the connection node connecting the station and the inter-station pipeline network is used as the basic variable to solve the general solution of the flow rate at the connection node,reconstruct the simulation model of the inter-station pipeline network,and reduce the equation set dimension of the inter-station pipeline network model.Thirdly,the transient simulation model of the natural gas pipeline network system is constructed based on the reconstructed simulation model of the inter-station pipeline network.Fnally,the calculation accuracy and efficiency of the proposed algorithm are compared and analyzed for the two working conditions of slow change of compressor speed and rapid shutdown of the compressor.And the following research results are obtained.First,the fracture-dimension-reduction algorithm has a high calculation accuracy,and the relative error of compressor outlet pressure and user pressure is less than 0.1%.Second,the calculation efficiency of the new fracture-dimension-reduction algorithm is high,and compared with the nonlinear equations solv ing method,the speed-up ratios under the two conditions are high up to 17.3 and 12.2 respectively.Third,the speed-up ratio of the fracture-dimension-reduction algorithm is linearly related to the equation set dimension of the transient simulation model of the pipeline network system.The larger the equation set dimension,the higher the speed-up ratio,which means the more complex the pipeline network model,the more remarkable the calculation speed-up effect.In conclusion,this new method improves the calculation speed while keeping the calculation accuracy,which is of great theoretical value and reference significance for improving the calculation efficiency of the transient simulation of complex natural gas pipeline network systems.展开更多
This article describes numerical simulation of gas pipeline network operation using high-accuracy computational fluid dynamics (CFD) simulators of the modes of gas mixture transmission through long, multi-line pipelin...This article describes numerical simulation of gas pipeline network operation using high-accuracy computational fluid dynamics (CFD) simulators of the modes of gas mixture transmission through long, multi-line pipeline systems (CFD-simulator). The approach used in CFD-simulators for modeling gas mixture transmission through long, branched, multi-section pipelines is based on tailoring the full system of fluid dynamics equations to conditions of unsteady, non-isothermal processes of the gas mixture flow. Identification, in a CFD-simulator, of safe parameters for gas transmission through compressor stations amounts to finding the interior points of admissible sets described by systems of nonlinear algebraic equalities and inequalities. Such systems of equalities and inequalities comprise a formal statement of technological, design, operational and other constraints to which operation of the network equipment is subject. To illustrate the practicability of the method of numerical simulation of a gas transmission network, we compare computation results and gas flow parameters measured on-site at the gas transmission enter-prise.展开更多
An integrated dynamic model of natural gas pipeline networks is developed in this paper.Components for gas supply,e.g.,pipelines,junctions,compressor stations,LNG terminals,regulation stations and gas storage faciliti...An integrated dynamic model of natural gas pipeline networks is developed in this paper.Components for gas supply,e.g.,pipelines,junctions,compressor stations,LNG terminals,regulation stations and gas storage facilities are included in the model.These components are firstly modeled with respect to their properties and functions and,then,integrated at the system level by Graph Theory.The model can be used for simulating the system response in different scenarios of operation,and evaluate the consequences from the perspectives of supply security and resilience.A case study is considered to evaluate the accuracy of the model by benchmarking its results against those from literature and the software Pipeline Studio.Finally,the model is applied on a relatively complex natural gas pipeline network and the results are analyzed in detail from the supply security and resilience points of view.The main contributions of the paper are:firstly,a novel model of a complex gas pipeline network is proposed as a dynamic state-space model at system level;a method,based on the dynamic model,is proposed to analyze the security and resilience of supply from a system perspective.展开更多
In the design of Hydraulic Manifold Blocks (HMB), dynamic performance of inner pipeline networks usually should be evaluated. To meet the design requirements, dynamic characteristic simulation is often needed. Based o...In the design of Hydraulic Manifold Blocks (HMB), dynamic performance of inner pipeline networks usually should be evaluated. To meet the design requirements, dynamic characteristic simulation is often needed. Based on comprehensive study on the existing simulation methods, a new method combined of Power Bond Graph(PBG) and Computational Fluid Dynamic (CFD) is proposed. In this method, flow field of typical channels inside HMB is analyzed with CFD to obtain the local resistance coefficients. Then, with these coefficients, a new sectional lumped-parameter model including kinetic friction factor is developed using PBG. A typical HMB design example is given and the comparison between the simulation and the experimental results demonstrates the feasibility and effectiveness of the proposed method.展开更多
The optimiz at ion operation of gas pipeline network is investigated in this paper. Based on th e theories of system optimization and the multi object decision, a mathematical model about the multi object optimization...The optimiz at ion operation of gas pipeline network is investigated in this paper. Based on th e theories of system optimization and the multi object decision, a mathematical model about the multi object optimization operation of gas pipeline network is established, in line with the demand of urban gas pipeline network operation. A t the same time, an effective solution of the mathematical model is presented. A calculating software about optimization operation is compiled, coupling the actual operation of gas pipeline network. It can be applied to the operation of the gas pipeline network. The software was examined by real examples. The resul ts indicated that 2.13% energy consumption and 3.12% gas supply cost can be reduced through optimization operation.展开更多
The interchangeability between natural gas of different sources and LNG have been concerned and tackled to a certain extent at home,and the interconnection of gas infrastructures including LNG terminals and gas pipeli...The interchangeability between natural gas of different sources and LNG have been concerned and tackled to a certain extent at home,and the interconnection of gas infrastructures including LNG terminals and gas pipeline networks have also been lifted up to the national level since 2018.However,the research on the interoperability with overall-planning interchangeability and interconnection at a higher level is still in the blank stage at home.By extensively investigating EU's regulations and practices related to interoperability in the field of natural gas pipeline network,this paper put forward the conceptual definition of the interoperability of gas infrastructures including LNG terminals and gas pipeline networks for the first time.Then,the basic implementation framework and components of interoperability were set up.Finally,domestic latest typical cases which have presented the characteristics of interoperability in the recent two years were analyzed.And the following research results were obtained.First,interoperability and third-party access are two independent themes.Second,the target of interoperability is to realize the cross-system unimpeded flow of natural gas of all facility users between different facilities according to the uniform specification of specific technical standards,operation criteria and operation procedures of various facilities,based on interconnection,coordination and information interaction.Third,the framework of interoperability consists of 8 key elements,including gas quality standard&interchangeability,facility interconnection,facility interconnection agreement,unified measurement unit,unified electronic data exchange platform,technical capacity calculation method,approval procedure of LNG carrier entering the port and ship-shore compatibility unique to LNG terminals,and gas quality based LNG storage and tank loading rules.Fourth,it is recommended to give consideration to both target and requirement of interoperability and fully integrate 3 elements that are discussed more deeply and more crucial in EU countries(i.e.,facility interconnection agreement,unified electronic data exchange platform and technical capacity calculation method)into the practice system of treatment reform of domestic natural gas industry chain.展开更多
In recent years, with the rapid development of economy and technology, many fields in China have been reformed and innovated and the urbanization process is advancing by leaps and bounds. Especially the intelligent ci...In recent years, with the rapid development of economy and technology, many fields in China have been reformed and innovated and the urbanization process is advancing by leaps and bounds. Especially the intelligent city construction has begun to take shape. Water network, power grid and gas network are the basic guarantee of peoples daily life. Perfecting urban infrastructure construction is an important content to improve peoples quality of life and accelerate the development of urban informatization. Urban gas pipeline network is laid in various underground cities. Intricate is an important channel for gas supply due to a series of problems such as uneven gas construction quality, difficult problem troubleshooting, complex operation of gas equipment and slow data update and scheduling. As a result, pipeline leakage and safety accidents occur frequently. Therefore, promoting the intelligentization of urban gas pipeline network operation and management is the key to current work. In the current electrical engineering field, intelligent technology shows positive advantages, mainly reflected in data collection, storage and editing and automation of gas pipeline network. This paper analyzes the advantages of intelligent management and the application of intelligent and automatic technology in the operation and management of urban gas pipeline network based on the current operation status of urban gas pipeline network.展开更多
Gas has brought convenience to people’s life at present, and gas pipeline networks and ancillary facilities play important roles in city construction. However, there are increasingly prominent safety problems in oper...Gas has brought convenience to people’s life at present, and gas pipeline networks and ancillary facilities play important roles in city construction. However, there are increasingly prominent safety problems in operation. The safe operation of gas pipeline networks in cities has been influenced by various aspects of factors, leading to frequent gas accidents, which give rise to serious influences on supply of gas. For this reason, detailed analysis has been conducted to problems related to safe operation of gas pipeline networks in cities in this article, and corresponding solutions are proposed.展开更多
Simulation has proven to be an effective tool for analyzing pipeline network systems （PNS） in order to determine the design and operational variables which are essential for evaluating the performance of the system....Simulation has proven to be an effective tool for analyzing pipeline network systems （PNS） in order to determine the design and operational variables which are essential for evaluating the performance of the system. This paper discusses the use of simulation for performance analysis of transmission PNS. A simulation model was developed for determining flow and pressure variables for different configuration of PNS. The mathematical formulation for the simulation model was derived based on the principles of energy conservation, mass balance, and compressor characteristics. For the determination of the pressure and flow variables, solution procedure was developed based on iterative Newton Raphson scheme and implemented using visual C＋＋6. Evaluations of the simulation model with the existing pipeline network system showed that the model enabled to determine the operational variables with less than ten iterations. The performances of the compressor working in the pipeline network system xvhich includes energy consumption, compression ratio and discharge pressure were evaluated to meet pressure requirements ranging from 4000-5000 kPa at various speed. Results of the analyses from the simulation indicated that the model could be used for performance analysis to assist decisions regarding the design and optimal operations of transmission PNS.展开更多
Natural gas is an emerging and reliable energy source in transition to a low-carbon economy.The natural gas transportation pipeline network systems are crucial when transporting natural gas from the production endpoin...Natural gas is an emerging and reliable energy source in transition to a low-carbon economy.The natural gas transportation pipeline network systems are crucial when transporting natural gas from the production endpoints to processing or consuming endpoints.Optimizing the operational efficiency of compressor stations within pipeline networks is an effective way to reduce energy consumption and carbon emissions during transportation.This paper proposes an optimization framework for natural gas transportation pipeline networks based on deep reinforcement learning(DRL).The mathematical simulation model is derived from mass balance,hydrodynamics principles of gas flow,and compressor characteristics.The optimization control problem in steady state is formulated into a one-step Markov decision process(MDP)and solved by DRL.The decision variables are selected as the discharge ratio of each compressor.By the comprehensive comparison with dynamic programming(DP)and genetic algorithm(GA)in three typical element topologies(a linear topology with gun-barrel structure,a linear topology with branch structure,and a tree topology),the proposed method can obtain 4.60%lower power consumption than GA,and the time consumption is reduced by 97.5%compared with DP.The proposed framework could be further utilized for future large-scale network optimization practices.展开更多
Oilfield treated oil pipeline network is the link connecting the upstream oilfields and the downstream refineries.Due to the differences in operating costs and transportation fee between different pipelines and the fl...Oilfield treated oil pipeline network is the link connecting the upstream oilfields and the downstream refineries.Due to the differences in operating costs and transportation fee between different pipelines and the fluctuation in the demand and sales prices of the treated oil,there is an optimal flow allocation plan for the pipeline network to make the oilfield company obtain the highest social and economic benefit.In this study,a mixed integer nonlinear programming(MINLP)model is developed to determine the optimal flow rate allocation plan of the large-scale and complex treated oil pipeline network,and both the social and economic benefits are considered simultaneously.The optimization objective is the multi-objective which includes the largest user satisfaction and the highest economic benefit.The model constraints include the oilfield production capacity,refinery demand,pipeline transmission capacity,flow,pressure,and temperature of the node and station,and the pipeline hydraulic and thermal calculations.Python 3.7 is utilized for the programming of the off-line calculation procedure and the MINLP model,and GUROBI 9.0.2 is served as the MINLP solver.Moreover,the model is applied to a real treated oil pipeline network located in China,and three optimization scenarios are analyzed.For social benefit,the values of the user satisfaction of each refinery and the total network are 1 before and after optimization for scenarios 1,2,and 3.For economic benefit,the annual revenue can be increased by 0.227,0.293,and 0.548 billion yuan after the optimization in scenario 1,2,and 3,respectively.展开更多
Eastern China＇s crude oil pipeline network is of the largest scale and freight volume in China.Here,we analyze 37 oil pipelines and one railway（38 oil flow channels）,20 oil fields with output of over a million tons...Eastern China＇s crude oil pipeline network is of the largest scale and freight volume in China.Here,we analyze 37 oil pipelines and one railway（38 oil flow channels）,20 oil fields with output of over a million tons of crude oil,and 32 refineries each of which refine over a million tons of crude oil.We construct a supply and demand balance sheet of oil sources and sinks by considering the transportation cost variance of variant pipeline diameters to determine the spatial optimization of Eastern China＇s pipeline network.In 2009,the optimal cost of this network was 34.5% lower than the total actual cost,suggesting that oil flow is overall inefficient and there is huge potential to improve flow efficiency.Within Eastern China,the oil flow of the Northeast network was relatively better than others,but the flow in Northern China is inefficient because all pipelines are underload or noload,and there were similar conditions in the Huanghuai region.We assumed no difference in pipeline transport speed,compared to rail or road transportation,thus transportation distance,rather than time,is the main influential factor under the definite transporting cost of variant pipeline diameters.展开更多
The seabed oil gas pipeline network is simplified to a network with stochastic edge weight by means of the fuzzy graphics theory. With the help of network analysis, fuzzy mathematics, and stochastic theory, the prob...The seabed oil gas pipeline network is simplified to a network with stochastic edge weight by means of the fuzzy graphics theory. With the help of network analysis, fuzzy mathematics, and stochastic theory, the problem of reliability analysis for the seabed oil gas pipeline network under earthquakes is transformed into the calculation of the transitive closure of fuzzy matrix of the stochastic fuzzy network. In classical network reliability analysis, the node is supposed to be non invalidated; in this paper, this premise is modified by introducing a disposal method which has taken the possible invalidated node into account. A good result is obtained by use of the Monte Carlo simulation analysis.展开更多
As typical lifeline engineering systems,urban pipeline networks(UPNs)play an important role in transmission and distribution of materials or energies in modern society.Over the past years,many efforts have been devote...As typical lifeline engineering systems,urban pipeline networks(UPNs)play an important role in transmission and distribution of materials or energies in modern society.Over the past years,many efforts have been devoted to the research,development and application towards intelligent operation and maintenance of UPNs in Tongji University,incorporating with the emerging artificial intelligence(AI)-based and internet of things(IoT)-based technologies.This paper presents a review on the recent advances and the important achievements pertaining to this field in Tongji University.Using multi-source data,a data-driven model for the comprehensive risk evaluation of the whole pipeline network is briefly introduced to address the limitation of the insufficiency of reliable data and demonstrated by a case study.Aiming at three major safety problems such as structural failure,leak and third-party intrusion,the advances in techniques and systems for health monitoring of urban pipelines are summarized and the various application scenarios are illustrated as well.展开更多
To analyze the working characteristics of complex compressed air networks, numerical methods are widely used which are based on finite element technology or intelligent algorithms. However, the effectiveness of the nu...To analyze the working characteristics of complex compressed air networks, numerical methods are widely used which are based on finite element technology or intelligent algorithms. However, the effectiveness of the numerical methods is limited. In this paper, to provide a new method to optimize the design and the air supply strategy of the complex compressed air pipe network, firstly, a novel method to analyze the topology structure of the compressed air flow in the pipe network is initially proposed. A matrix is used to describe the topology structure of the compressed air flow. Moreover, based on the analysis of the pressure loss of the pipe network, the relationship between the pressure and the flow of the compressed air is derived, and a prediction method of pressure fluctuation and air flow in a segment in a complex pipe network is proposed. Finally, to inspect the effectiveness of the method, an experiment with a complex network is designed. The pressure and the flow of airflow in the network are measured and studied. The results of the study show that, the predicted results with the proposed method have a good consistency with the experimental results, and that verifies the air flow prediction method of the complex pipe network. This research proposes a new method to analyze the compressed air network and a prediction method of pressure fluctuation and air flow in a segment, which can predicate the fluctuation of the pressure according to the flow of compressed air, and predicate the fluctuation of the flow according to the pressure in a segment of a complex pipe network.展开更多
In short-term operation of natural gas network,the impact of demand uncertainty is not negligible.To address this issue we propose a two-stage robust model for power cost minimization problem in gunbarrel natural gas ...In short-term operation of natural gas network,the impact of demand uncertainty is not negligible.To address this issue we propose a two-stage robust model for power cost minimization problem in gunbarrel natural gas networks.The demands between pipelines and compressor stations are uncertain with a budget parameter,since it is unlikely that all the uncertain demands reach the maximal deviation simultaneously.During solving the two-stage robust model we encounter a bilevel problem which is challenging to solve.We formulate it as a multi-dimensional dynamic programming problem and propose approximate dynamic programming methods to accelerate the calculation.Numerical results based on real network in China show that we obtain a speed gain of 7 times faster in average without compromising optimality compared with original dynamic programming algorithm.Numerical results also verify the advantage of robust model compared with deterministic model when facing uncertainties.These findings offer short-term operation methods for gunbarrel natural gas network management to handle with uncertainties.展开更多
Under China's goal of carbon neutrality,there is a huge demand for carbon dioxide(CO_(2))capture,utilization,and storage technology(CCUS).CO_(2) transport,as a crucial link in the CCUS industrial chain,will inevit...Under China's goal of carbon neutrality,there is a huge demand for carbon dioxide(CO_(2))capture,utilization,and storage technology(CCUS).CO_(2) transport,as a crucial link in the CCUS industrial chain,will inevitably rely on the construction of long-distance CO_(2) pipelines and infrastructure.Due to the late start and small scale of China's CO_(2) pipeline construction,and the relative lag in related technologies and policies,it is urgent to make systematical planning and achieve relevant technological breakthroughs for the future construction of CO_(2) pipeline network as a public infrastructure.Therefore,a three-stage pipeline development path is proposed based on the analysis of the spatial distribution characteristics and the temporal pattern of large-scale commercial development of CO_(2) carbon sources and storage in China.Moreover,solutions and suggestions are proposed upon the developments analysis in China from the perspectives of pipeline transportation technology,safety evaluation,materials and equipment,and integrity.The results show that the construction of CO_(2) pipeline network as an important CCUS infrastructure will accelerate with the development of the global CCUS industry;the spatial distribution of CO_(2) emission sources and storage is unbalanced in China,with 65.8%from the eastern and central China,and CO_(2)flooding and geological storage contributing to most of large-scale CO_(2) pipeline transportation.The conclusions are as follows.First,the three-stage development path is a million-ton demonstration project of supercritical CO_(2) transmission pipeline before China peaks carbon emissions.After the achievement of carbon peak,a 10 million-ton regional network architecture of CO_(2) pipeline network centered on basins will be built,and trunk pipelines between regions will be formed before achieving carbon neutrality,establishing the national carbon transmission network with a transportation capacity of 10108 ton,and a total mileage of approximately 6104 km.Second,we should carry out research on the technology and equipment for the full phase CO_(2) pipeline transportation onshore and offshore,improve the domestic pipeline transportation technology,and promote the continuous improvement of the regulatory system in the pipeline transportation industry,so as to facilitate the implementation of demonstration projects.展开更多
China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determin...China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determined by competition, oil and gas pipeline facilities will be opened fairly, and private enterprises will play important roles in natural gas exploration, development, storage, transportation, and trade. It can been foreseen that China natural gas industry is very likely to take a turn in next 10 years, and a modern natural gas market with consumption about 500 billion cubic meters will come into being characterized by complete supervision system, diversified market, steady supply, fairly opened pipelines, transparent trading mechanism, and competitive prices.展开更多
China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determin...China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determined by competition, oil and gas pipeline facilities will be opened fairly, and private enterprises will play important roles in natural gas exploration, development, storage, transportation, and trade. It can been foreseen that China natural gas industry is very likely to take a turn in next 10 years, and a modern natural gas market with consumption about 500 billion cubic meters will come into being characterized by complete supervision system, diversified market, steady supply, fairly opened pipelines, transparent trading mechanism, and competitive prices.展开更多
文摘This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dynamics model of sewage treatment facility expansion.Elaborating on detection technology,construction of an intelligent operation and maintenance system,and factors to be considered for sewage plant expansion,it emphasizes the importance of collaborative development and verifies benefits through the PSR model.
文摘The transient simulation technology of natural gas pipeline networks plays an increasingly prominent role in the scheduling management of natural gas pipeline network system.The increasingly large and complex natural gas pipeline network requires more strictly on the calculation efficiency of transient simulation.To this end,this paper proposes a new method for the transient simulation of natural gas pipeline networks based on fracture-dimension-reduction algorithm.Firstly,a pipeline network model is abstracted into a station model,inter-station pipeline network model and connection node model.Secondlly,the pressure at the connection node connecting the station and the inter-station pipeline network is used as the basic variable to solve the general solution of the flow rate at the connection node,reconstruct the simulation model of the inter-station pipeline network,and reduce the equation set dimension of the inter-station pipeline network model.Thirdly,the transient simulation model of the natural gas pipeline network system is constructed based on the reconstructed simulation model of the inter-station pipeline network.Fnally,the calculation accuracy and efficiency of the proposed algorithm are compared and analyzed for the two working conditions of slow change of compressor speed and rapid shutdown of the compressor.And the following research results are obtained.First,the fracture-dimension-reduction algorithm has a high calculation accuracy,and the relative error of compressor outlet pressure and user pressure is less than 0.1%.Second,the calculation efficiency of the new fracture-dimension-reduction algorithm is high,and compared with the nonlinear equations solv ing method,the speed-up ratios under the two conditions are high up to 17.3 and 12.2 respectively.Third,the speed-up ratio of the fracture-dimension-reduction algorithm is linearly related to the equation set dimension of the transient simulation model of the pipeline network system.The larger the equation set dimension,the higher the speed-up ratio,which means the more complex the pipeline network model,the more remarkable the calculation speed-up effect.In conclusion,this new method improves the calculation speed while keeping the calculation accuracy,which is of great theoretical value and reference significance for improving the calculation efficiency of the transient simulation of complex natural gas pipeline network systems.
文摘This article describes numerical simulation of gas pipeline network operation using high-accuracy computational fluid dynamics (CFD) simulators of the modes of gas mixture transmission through long, multi-line pipeline systems (CFD-simulator). The approach used in CFD-simulators for modeling gas mixture transmission through long, branched, multi-section pipelines is based on tailoring the full system of fluid dynamics equations to conditions of unsteady, non-isothermal processes of the gas mixture flow. Identification, in a CFD-simulator, of safe parameters for gas transmission through compressor stations amounts to finding the interior points of admissible sets described by systems of nonlinear algebraic equalities and inequalities. Such systems of equalities and inequalities comprise a formal statement of technological, design, operational and other constraints to which operation of the network equipment is subject. To illustrate the practicability of the method of numerical simulation of a gas transmission network, we compare computation results and gas flow parameters measured on-site at the gas transmission enter-prise.
基金supported by National Natural Science Foundation of China[grant number 51904316]provided by China University of Petroleum,Beijing[grant number2462021YJRC013,2462020YXZZ045]
文摘An integrated dynamic model of natural gas pipeline networks is developed in this paper.Components for gas supply,e.g.,pipelines,junctions,compressor stations,LNG terminals,regulation stations and gas storage facilities are included in the model.These components are firstly modeled with respect to their properties and functions and,then,integrated at the system level by Graph Theory.The model can be used for simulating the system response in different scenarios of operation,and evaluate the consequences from the perspectives of supply security and resilience.A case study is considered to evaluate the accuracy of the model by benchmarking its results against those from literature and the software Pipeline Studio.Finally,the model is applied on a relatively complex natural gas pipeline network and the results are analyzed in detail from the supply security and resilience points of view.The main contributions of the paper are:firstly,a novel model of a complex gas pipeline network is proposed as a dynamic state-space model at system level;a method,based on the dynamic model,is proposed to analyze the security and resilience of supply from a system perspective.
基金National Natural Science Foundation of China (No.50375023)
文摘In the design of Hydraulic Manifold Blocks (HMB), dynamic performance of inner pipeline networks usually should be evaluated. To meet the design requirements, dynamic characteristic simulation is often needed. Based on comprehensive study on the existing simulation methods, a new method combined of Power Bond Graph(PBG) and Computational Fluid Dynamic (CFD) is proposed. In this method, flow field of typical channels inside HMB is analyzed with CFD to obtain the local resistance coefficients. Then, with these coefficients, a new sectional lumped-parameter model including kinetic friction factor is developed using PBG. A typical HMB design example is given and the comparison between the simulation and the experimental results demonstrates the feasibility and effectiveness of the proposed method.
文摘The optimiz at ion operation of gas pipeline network is investigated in this paper. Based on th e theories of system optimization and the multi object decision, a mathematical model about the multi object optimization operation of gas pipeline network is established, in line with the demand of urban gas pipeline network operation. A t the same time, an effective solution of the mathematical model is presented. A calculating software about optimization operation is compiled, coupling the actual operation of gas pipeline network. It can be applied to the operation of the gas pipeline network. The software was examined by real examples. The resul ts indicated that 2.13% energy consumption and 3.12% gas supply cost can be reduced through optimization operation.
文摘The interchangeability between natural gas of different sources and LNG have been concerned and tackled to a certain extent at home,and the interconnection of gas infrastructures including LNG terminals and gas pipeline networks have also been lifted up to the national level since 2018.However,the research on the interoperability with overall-planning interchangeability and interconnection at a higher level is still in the blank stage at home.By extensively investigating EU's regulations and practices related to interoperability in the field of natural gas pipeline network,this paper put forward the conceptual definition of the interoperability of gas infrastructures including LNG terminals and gas pipeline networks for the first time.Then,the basic implementation framework and components of interoperability were set up.Finally,domestic latest typical cases which have presented the characteristics of interoperability in the recent two years were analyzed.And the following research results were obtained.First,interoperability and third-party access are two independent themes.Second,the target of interoperability is to realize the cross-system unimpeded flow of natural gas of all facility users between different facilities according to the uniform specification of specific technical standards,operation criteria and operation procedures of various facilities,based on interconnection,coordination and information interaction.Third,the framework of interoperability consists of 8 key elements,including gas quality standard&interchangeability,facility interconnection,facility interconnection agreement,unified measurement unit,unified electronic data exchange platform,technical capacity calculation method,approval procedure of LNG carrier entering the port and ship-shore compatibility unique to LNG terminals,and gas quality based LNG storage and tank loading rules.Fourth,it is recommended to give consideration to both target and requirement of interoperability and fully integrate 3 elements that are discussed more deeply and more crucial in EU countries(i.e.,facility interconnection agreement,unified electronic data exchange platform and technical capacity calculation method)into the practice system of treatment reform of domestic natural gas industry chain.
文摘In recent years, with the rapid development of economy and technology, many fields in China have been reformed and innovated and the urbanization process is advancing by leaps and bounds. Especially the intelligent city construction has begun to take shape. Water network, power grid and gas network are the basic guarantee of peoples daily life. Perfecting urban infrastructure construction is an important content to improve peoples quality of life and accelerate the development of urban informatization. Urban gas pipeline network is laid in various underground cities. Intricate is an important channel for gas supply due to a series of problems such as uneven gas construction quality, difficult problem troubleshooting, complex operation of gas equipment and slow data update and scheduling. As a result, pipeline leakage and safety accidents occur frequently. Therefore, promoting the intelligentization of urban gas pipeline network operation and management is the key to current work. In the current electrical engineering field, intelligent technology shows positive advantages, mainly reflected in data collection, storage and editing and automation of gas pipeline network. This paper analyzes the advantages of intelligent management and the application of intelligent and automatic technology in the operation and management of urban gas pipeline network based on the current operation status of urban gas pipeline network.
文摘Gas has brought convenience to people’s life at present, and gas pipeline networks and ancillary facilities play important roles in city construction. However, there are increasingly prominent safety problems in operation. The safe operation of gas pipeline networks in cities has been influenced by various aspects of factors, leading to frequent gas accidents, which give rise to serious influences on supply of gas. For this reason, detailed analysis has been conducted to problems related to safe operation of gas pipeline networks in cities in this article, and corresponding solutions are proposed.
文摘Simulation has proven to be an effective tool for analyzing pipeline network systems （PNS） in order to determine the design and operational variables which are essential for evaluating the performance of the system. This paper discusses the use of simulation for performance analysis of transmission PNS. A simulation model was developed for determining flow and pressure variables for different configuration of PNS. The mathematical formulation for the simulation model was derived based on the principles of energy conservation, mass balance, and compressor characteristics. For the determination of the pressure and flow variables, solution procedure was developed based on iterative Newton Raphson scheme and implemented using visual C＋＋6. Evaluations of the simulation model with the existing pipeline network system showed that the model enabled to determine the operational variables with less than ten iterations. The performances of the compressor working in the pipeline network system xvhich includes energy consumption, compression ratio and discharge pressure were evaluated to meet pressure requirements ranging from 4000-5000 kPa at various speed. Results of the analyses from the simulation indicated that the model could be used for performance analysis to assist decisions regarding the design and optimal operations of transmission PNS.
基金financial support to conduct this work,and acknowledges Aramco Americas for their support under grant ASC AGREEMENT NO.CW57093.
文摘Natural gas is an emerging and reliable energy source in transition to a low-carbon economy.The natural gas transportation pipeline network systems are crucial when transporting natural gas from the production endpoints to processing or consuming endpoints.Optimizing the operational efficiency of compressor stations within pipeline networks is an effective way to reduce energy consumption and carbon emissions during transportation.This paper proposes an optimization framework for natural gas transportation pipeline networks based on deep reinforcement learning(DRL).The mathematical simulation model is derived from mass balance,hydrodynamics principles of gas flow,and compressor characteristics.The optimization control problem in steady state is formulated into a one-step Markov decision process(MDP)and solved by DRL.The decision variables are selected as the discharge ratio of each compressor.By the comprehensive comparison with dynamic programming(DP)and genetic algorithm(GA)in three typical element topologies(a linear topology with gun-barrel structure,a linear topology with branch structure,and a tree topology),the proposed method can obtain 4.60%lower power consumption than GA,and the time consumption is reduced by 97.5%compared with DP.The proposed framework could be further utilized for future large-scale network optimization practices.
基金the Natural Science Foundation of Chongqing,China (No.cstc2021jcyj-msxmX0918)the Science and Technology Research Program of Chongqing Municipal Education Commission (No.KJQN202101545)+1 种基金the National Natural Science Foundation of China (52302402)the Research Foundation of Chongqing University of Science and Technology (ckrc2021003)for providing support for this work.
文摘Oilfield treated oil pipeline network is the link connecting the upstream oilfields and the downstream refineries.Due to the differences in operating costs and transportation fee between different pipelines and the fluctuation in the demand and sales prices of the treated oil,there is an optimal flow allocation plan for the pipeline network to make the oilfield company obtain the highest social and economic benefit.In this study,a mixed integer nonlinear programming(MINLP)model is developed to determine the optimal flow rate allocation plan of the large-scale and complex treated oil pipeline network,and both the social and economic benefits are considered simultaneously.The optimization objective is the multi-objective which includes the largest user satisfaction and the highest economic benefit.The model constraints include the oilfield production capacity,refinery demand,pipeline transmission capacity,flow,pressure,and temperature of the node and station,and the pipeline hydraulic and thermal calculations.Python 3.7 is utilized for the programming of the off-line calculation procedure and the MINLP model,and GUROBI 9.0.2 is served as the MINLP solver.Moreover,the model is applied to a real treated oil pipeline network located in China,and three optimization scenarios are analyzed.For social benefit,the values of the user satisfaction of each refinery and the total network are 1 before and after optimization for scenarios 1,2,and 3.For economic benefit,the annual revenue can be increased by 0.227,0.293,and 0.548 billion yuan after the optimization in scenario 1,2,and 3,respectively.
基金National Natural Science Foundation of China(41371518)The Priority Academic Program Development of Jiangsu Higher Education Institutions+1 种基金Natural Science Research Foundation of Jiangsu Higher Education Institutions(10KJB170006)Scientific Research Start-up Funds of Changzhou University
文摘Eastern China＇s crude oil pipeline network is of the largest scale and freight volume in China.Here,we analyze 37 oil pipelines and one railway（38 oil flow channels）,20 oil fields with output of over a million tons of crude oil,and 32 refineries each of which refine over a million tons of crude oil.We construct a supply and demand balance sheet of oil sources and sinks by considering the transportation cost variance of variant pipeline diameters to determine the spatial optimization of Eastern China＇s pipeline network.In 2009,the optimal cost of this network was 34.5% lower than the total actual cost,suggesting that oil flow is overall inefficient and there is huge potential to improve flow efficiency.Within Eastern China,the oil flow of the Northeast network was relatively better than others,but the flow in Northern China is inefficient because all pipelines are underload or noload,and there were similar conditions in the Huanghuai region.We assumed no difference in pipeline transport speed,compared to rail or road transportation,thus transportation distance,rather than time,is the main influential factor under the definite transporting cost of variant pipeline diameters.
文摘The seabed oil gas pipeline network is simplified to a network with stochastic edge weight by means of the fuzzy graphics theory. With the help of network analysis, fuzzy mathematics, and stochastic theory, the problem of reliability analysis for the seabed oil gas pipeline network under earthquakes is transformed into the calculation of the transitive closure of fuzzy matrix of the stochastic fuzzy network. In classical network reliability analysis, the node is supposed to be non invalidated; in this paper, this premise is modified by introducing a disposal method which has taken the possible invalidated node into account. A good result is obtained by use of the Monte Carlo simulation analysis.
基金supported by the National Key Research and Development Program[Grant No.2016YFC0802400].
文摘As typical lifeline engineering systems,urban pipeline networks(UPNs)play an important role in transmission and distribution of materials or energies in modern society.Over the past years,many efforts have been devoted to the research,development and application towards intelligent operation and maintenance of UPNs in Tongji University,incorporating with the emerging artificial intelligence(AI)-based and internet of things(IoT)-based technologies.This paper presents a review on the recent advances and the important achievements pertaining to this field in Tongji University.Using multi-source data,a data-driven model for the comprehensive risk evaluation of the whole pipeline network is briefly introduced to address the limitation of the insufficiency of reliable data and demonstrated by a case study.Aiming at three major safety problems such as structural failure,leak and third-party intrusion,the advances in techniques and systems for health monitoring of urban pipelines are summarized and the various application scenarios are illustrated as well.
基金Supported by National Natural Science Foundation of China(Grant No.51205008)
文摘To analyze the working characteristics of complex compressed air networks, numerical methods are widely used which are based on finite element technology or intelligent algorithms. However, the effectiveness of the numerical methods is limited. In this paper, to provide a new method to optimize the design and the air supply strategy of the complex compressed air pipe network, firstly, a novel method to analyze the topology structure of the compressed air flow in the pipe network is initially proposed. A matrix is used to describe the topology structure of the compressed air flow. Moreover, based on the analysis of the pressure loss of the pipe network, the relationship between the pressure and the flow of the compressed air is derived, and a prediction method of pressure fluctuation and air flow in a segment in a complex pipe network is proposed. Finally, to inspect the effectiveness of the method, an experiment with a complex network is designed. The pressure and the flow of airflow in the network are measured and studied. The results of the study show that, the predicted results with the proposed method have a good consistency with the experimental results, and that verifies the air flow prediction method of the complex pipe network. This research proposes a new method to analyze the compressed air network and a prediction method of pressure fluctuation and air flow in a segment, which can predicate the fluctuation of the pressure according to the flow of compressed air, and predicate the fluctuation of the flow according to the pressure in a segment of a complex pipe network.
基金partially supported by the National Science Foundation of China(Grants 71822105 and 91746210)。
文摘In short-term operation of natural gas network,the impact of demand uncertainty is not negligible.To address this issue we propose a two-stage robust model for power cost minimization problem in gunbarrel natural gas networks.The demands between pipelines and compressor stations are uncertain with a budget parameter,since it is unlikely that all the uncertain demands reach the maximal deviation simultaneously.During solving the two-stage robust model we encounter a bilevel problem which is challenging to solve.We formulate it as a multi-dimensional dynamic programming problem and propose approximate dynamic programming methods to accelerate the calculation.Numerical results based on real network in China show that we obtain a speed gain of 7 times faster in average without compromising optimality compared with original dynamic programming algorithm.Numerical results also verify the advantage of robust model compared with deterministic model when facing uncertainties.These findings offer short-term operation methods for gunbarrel natural gas network management to handle with uncertainties.
文摘Under China's goal of carbon neutrality,there is a huge demand for carbon dioxide(CO_(2))capture,utilization,and storage technology(CCUS).CO_(2) transport,as a crucial link in the CCUS industrial chain,will inevitably rely on the construction of long-distance CO_(2) pipelines and infrastructure.Due to the late start and small scale of China's CO_(2) pipeline construction,and the relative lag in related technologies and policies,it is urgent to make systematical planning and achieve relevant technological breakthroughs for the future construction of CO_(2) pipeline network as a public infrastructure.Therefore,a three-stage pipeline development path is proposed based on the analysis of the spatial distribution characteristics and the temporal pattern of large-scale commercial development of CO_(2) carbon sources and storage in China.Moreover,solutions and suggestions are proposed upon the developments analysis in China from the perspectives of pipeline transportation technology,safety evaluation,materials and equipment,and integrity.The results show that the construction of CO_(2) pipeline network as an important CCUS infrastructure will accelerate with the development of the global CCUS industry;the spatial distribution of CO_(2) emission sources and storage is unbalanced in China,with 65.8%from the eastern and central China,and CO_(2)flooding and geological storage contributing to most of large-scale CO_(2) pipeline transportation.The conclusions are as follows.First,the three-stage development path is a million-ton demonstration project of supercritical CO_(2) transmission pipeline before China peaks carbon emissions.After the achievement of carbon peak,a 10 million-ton regional network architecture of CO_(2) pipeline network centered on basins will be built,and trunk pipelines between regions will be formed before achieving carbon neutrality,establishing the national carbon transmission network with a transportation capacity of 10108 ton,and a total mileage of approximately 6104 km.Second,we should carry out research on the technology and equipment for the full phase CO_(2) pipeline transportation onshore and offshore,improve the domestic pipeline transportation technology,and promote the continuous improvement of the regulatory system in the pipeline transportation industry,so as to facilitate the implementation of demonstration projects.
文摘China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determined by competition, oil and gas pipeline facilities will be opened fairly, and private enterprises will play important roles in natural gas exploration, development, storage, transportation, and trade. It can been foreseen that China natural gas industry is very likely to take a turn in next 10 years, and a modern natural gas market with consumption about 500 billion cubic meters will come into being characterized by complete supervision system, diversified market, steady supply, fairly opened pipelines, transparent trading mechanism, and competitive prices.
文摘China natural gas industry is at a turning point. Growth of mid-long term natural gas consumption may maintain at about 10%, supply is sufficient or even "over-sufficient", natural gas price will be determined by competition, oil and gas pipeline facilities will be opened fairly, and private enterprises will play important roles in natural gas exploration, development, storage, transportation, and trade. It can been foreseen that China natural gas industry is very likely to take a turn in next 10 years, and a modern natural gas market with consumption about 500 billion cubic meters will come into being characterized by complete supervision system, diversified market, steady supply, fairly opened pipelines, transparent trading mechanism, and competitive prices.
