Gas Supply Network Research Articles

Centralization of gas supply systems based on butane-air mixture

The expansion of the construction of cottage villages, isolated settlements in ecologically clean areas, away from large cities, as well as the provision of gas to the settlements of the eastern part of the Russian Federation, sets the task of developing autonomous gas supply systems. A significant deterrent to the development of autonomous gas supply systems based on butane mixtures with air is their high cost and the absence of scientifically sound recommendations for choosing system parameters. To develop scientifically sound recommendations for the design of systems, considering all the factors of influence that ensure the optimal cost of gasification and subsequent maintenance by the consumer, additional studies are necessary. The article considers the choice of optimal centralization of gas supply systems based on a mixture of butane with air to determine the minimum cost of construction and operation for consumers. the systems analysis, mathematic model methods with calculation of optimal values in the presence of corresponding limits and the methods of material correlation processing are used. The data have been obtained for effective centralization of gas supply systems based on butane-air mixture. The criteria are set which influence the optimum number of houses connected to a tank installation, such as population density in a gas supplied area, climatic features of an area, a type of consumer’s gas-using equipment and a form of settlement development. As a result of the research, the optimum number of apartments has been determined for gas supply to a settlement connected to a tank installation. These recommendations will make it possible to increase efficiency of gas supply source selection and consumer connecting to a gas sup-ply network at minimum cost for consumers

Energy characteristics of induction water heater

Many agricultural facilities do not have the ability to connect to gas supply networks; at such facilities electric water heaters are used as sources of thermal energy for heating and hot water systems. The issue of the use of induction heating as one of the most effective at such facilities is relevant. The aim of this work is to study energy characteristics of an induction water heater, such as efficiency and power factor. In order to determine the estimated efficiency and power factor the energy balance method was used. The experimental values of the efficiency and power factor are determined by the calorimetric method and with the help of an electric energy quality analyzer. The obtained value of the efficiency and power factor of the induction water heater corresponds to the calculated value with an accuracy of ±1%.

Аналіз соціальної та енерго- і природозбережної ефективності реалізації біогазової технології

The development of the biogas market in Ukraine is expected to allow to replace 2.6… 18 billion m3 of natural gas per year, which will enhance the country’s energy security, create new jobs, economic development of the regions, allow to cover peak loads in the electricity grid, utilize plant waste, as well as some food industry waste. Biogas technologies are properly integrated into the UN Doctrine of Sustainable Development. The cycle of one of them is the beginning of the second cycle. This results in virtually complete waste-free production and intensification of production at a sufficient distance from the dynamic ecosystem equilibrium boundaries. Such a comprehensive approach, from the point of view of UN experts, when waste and by-products of one production act as raw materials or semi-finished products for another, will be able to completely solve the problem of sustainable development of society The main constituent effects (products) of biogas technology are analyzed: socio-ecological, agrotechnical (biofertilizer), energy. The exergy method of complex estimation of efficiency of biogas technology is formulated. A generalized functional diagram of biogas technology is proposed. The effectiveness of different options for utilization of biogas produced, including the use of direct combustion heat generators, internal combustion engines, steam turbine, gas turbine and microturbine installations, triggering systems, as well as technologies for biomethane production and its addition to the gas supply network are analyzed. According to the results of the research, rational variants of biogas utilization for biogas plants of different sizes have been identified. Groups of factors of influence on the processes of methanogenesis in biogas plants have been established. Physical factors of influence on the intensity of the fermentation process are analyzed. Technical and organizational solutions for improving the efficiency of biogas plants are proposed.

Day‐ahead energy management framework for a networked gas–heat–electricity microgrid

The integration of various energy supplying systems increases the energy efficiency and energy system reliability. Smart microgrids are an ideal area to use multi-carrier energy systems. In this context, this study presents a novel modelling framework for optimal day-ahead scheduling of a networked multi-carrier energy microgrid (NMCEMG) system. The NMCEMG system in this study is composed of heat, gas, and power supply networks. The presented framework has enhanced the multi-carrier microgrid modelling against the previous works that modelled the multi-carrier microgrid as an energy hub due to difficulties in the energy flow analysis of heat and gas networks. The proposed framework optimises the day-ahead operating cost of the NMCEMG system considering nodal and energy flow constraints of each network. The proposed microgrid includes various energy interdependent equipment such as combined heat and power units, gas-fired boilers, power to gas units, electrical and heat storages and electric heat pumps. This study presents a new optimisation algorithm named self-adaptive modified whale optimisation algorithm based on wavelet theory to solve the day-ahead optimal scheduling of the NMCEMG problem. The numerical results corroborate the proposed modelling framework as superior over conventional hub-based multi-carrier microgrid models in terms of energy system security.

Impact of gas composition variations on flame blowout and spectroscopic characteristics of lean premixed swirl flames

The injection of gases from different oil and gas fields and external sources such as liquefied natural gas increases operational risks for the relevant gas turbine power plant operators. In practice, the absence of interchangeability specifications in the gas supply network code has caused combustion blowout, wear and tear to occur due to combustion dynamics and diluent effects. Understanding the effects of diluents on natural gas combustion is essential to ensure the safe operation of existing facilities. The present work investigates the flame stability and spectroscopic characteristics of diluents-containing natural gas by using a swirl flame burner. Stable and continuous swirl flames were successfully established using different types of gas compositions, including those diluted with nitrogen and carbon dioxide. Diluting the modelled natural gas with CO2 and N2 results in higher blowout limit as compared to the baseline pure methane case. Preheating the burner and mixtures can extend the flame blowout limits, although the effect of CO2 on flame blowout is more pronounced than that of N2 due to its higher heat capacity. This work shows the effects of non-reactive diluents on gas turbine flame can be significant, particularly at high-level dilutions. Mitigation measures such as gas composition and flame spectroscopy monitoring can be deployed to ensure safe operation of the system. By using the statistical analysis technique of linear regression, the proportions of all the fuel mixture components of CH4, C2H6, CO2 and N2, alongside temperature were found to be significant factors in determining flame blowout limits. The developed predictor equations for OH intensity and lean blowout equivalence ratios show the predictive capability of >89% at 90–95% confidence level.

Unmanned Aerial Vehicles in the protection of the elements of a country’s critical infrastructure – selected directions of development

<i>This paper explores the directions for the application of unmanned aerial vehicles in the provision of security to vital elements of a country’s critical infrastructure. The analysis focuses on two paths of development: the first one refers to the transportation system, the latter is related to the gas supply network – the basic components of a country’s critical infrastructure. The first section of this paper will examine the current state of knowledge in the field, and is designed as a reference of terminology pertaining to unmanned aerial vehicles (definitions and classification). The section shall furthermore provide a basis for and a contribution to the developed conceptual-semantic framework for UAV research. The first direction of development is described in terms of the characteristics and assumptions of the system; this includes an overview of the specific requirements of the unmanned platform itself, as well as the elements of the system, such as a local monitoring centre and other components. Furthermore, this section provides the overview of the designated mobile application, whose development is expected to improve the efficiency of system operation, which is a conceptual novelty considering similar developments. The second direction concerns the development of an unmanned system of production, storage, and use of chemical and radioactive substances, including pipelines for hazardous substances. The programme that fits perfectly in the framework of the second considered branch of development is “Cricket” [Polish: “Świerszcz”] – a programme implemented in the periodic inspection of gas supply infrastructure. The description of the programme in question included specifying the technical and operational requirements for the fight devices as well as for the equipment.</i>

Condition based opportunistic preventive maintenance policy for utility systems with both economic and structural dependencies [formula omitted] application to a gas supply network

The main challenge in the maintenance planing lies in the realistic modeling of the maintenance policy. However, the complexity of the industrial systems makes difficult the achievement of this prospect. To face the realistic constraints, the present paper provides an approach for the maintenance planning of utility systems on the basis of opportunistic maintenance policy and Bayesian theory. The reliability assessment, which can be updated according to the evolution of the environmental conditions using the Bayesian theory, is integrated in the maintenance model, in order to evaluate the optimal preventive maintenance times and to update them when new degradation data become available. The opportunistic replacement is used to take benefit from the non-operating state of some components, caused by the maintenance action on other components, in order to replace them opportunistically. The effectiveness of the proposed approach is illustrated through a numerical application on operating gas supply system.

Optimal Energy Flow Calculation of Combined Natural Gas, Cooling, Heating and Power Joint Supply Park Microgrid

The combined natural gas, cooling, heating and power joint supply (CNCHP) microgrid of an industrial park has the advantages of cascaded use of energy, which can effectively improve energy efficiency and reduce pollutant emissions. In this paper, the optimal energy flow calculation model of CNCHP microgrid is established. Minimizing the total running cost of the microgrid is as the objective function, and the network operation characteristics of the cooling network, heating network, power supply network and gas supply network is considered. The model includes the loss characteristics and security operation constraints of various types of energy networks, and the obtained optimal operation schedule can meet the actual operational requirements of the microgrid. Taking a CNCHP microgrid of an industrial park as an example, the correctness and validness of the proposed optimal calculation model are verified. The results show that the optimal operation scheme of the CNCHP microgrid can effectively reduce the operating cost and improve the energy efficiency.

Expansion of the Italian natural gas network to the Sardinia Island: Economic assessment

About fifteen years ago, the GALSI pipeline was projected to connect Algeria and Italy by crossing the Mediterranean Sea. This has suggested the opportunity to provide natural gas to households and firms of the Sardinia Island, since a gas supply network was lacking in the region. Currently, although the GALSI pipeline is no more on the agenda, investments to equip many Sardinian municipalities with local gas networks are still carried on. The analysis we perform is twofold. Firstly, we estimate the likely natural gas consumption in 89 municipalities of the island. Subsequently, we focus on the economic viability of the local gas networks both from the public and the private point of view. The former perspective considers the public funds as outflows and the taxes levied on gas consumptions as inflows. The latter perspective aims to measure the yield rate for the private investors. Here we show that the projects are worth to be subsidized, although not all of them are palatable for the private partners. However, the most problematic finding concerns the allocation of the public funds, which has been found to be inconsistent with the underlying demographic and socio-economic conditions that drive natural gas consumptions. The irrational distribution of the grants causes that some local networks are over-subsidized and highly profitable for the private partners, while others are under-subsidized and characterized by a poor economic attractiveness for the investors. Moreover, the overall amount of grants is by far higher than the amount that would suffice.

Seismic reliability evaluation of gas supply networks based on the probability density evolution method

An accurate and efficient reliability evaluation is necessary for network systems with uncertain conditions, especially for the lifeline networks subjected to earthquakes. This study takes gas supply networks as examples and establishes an approach to evaluate the seismic reliability of networks on the basis of the probability density evolution method. First, a nonlinear finite element model is established to simulate buried pipe networks that are subjected to earthquakes. Then, the seismic stresses of the pipes are derived, and the von Mises stresses of the pipes are calculated and used to judge pipe failure. Second, a connectivity index is defined to describe the connectivity between the source and the terminal. Third, on the basis of the probability density evolution method, network reliability is obtained after introducing a physically-based model to simulate ground motion field. Finally, two networks are used as examples to demonstrate the proposed approach, and the results are validated by the Monte Carlo simulation method and compared with a selective recursive decomposition algorithm.

Uncovering hidden flows in physical networks

Understanding the interactions among nodes in a complex network is of great importance, since they disclose how these nodes are cooperatively supporting the functioning of the network. Scientists have developed numerous methods to uncover the underlying adjacent physical connectivity based on measurements of functional quantities of the nodes states. Often, the physical connectivity, the adjacency matrix, is available. Yet, little is known about how this adjacent connectivity impacts on the “hidden” flows being exchanged between any two arbitrary nodes, after travelling longer non-adjacent paths. In this letter, we show that hidden physical flows in conservative flow networks, a quantity that is usually inaccessible to measurements, can be determined by the interchange of physical flows between any pair of adjacent nodes. Our approach applies to steady or dynamic state of either linear or non-linear complex networks that can be modelled by conservative flow networks, such as gas supply networks, water supply networks and power grids.

Influence of the total static gas pressure difference on blast-furnace performance

Further evidence is found to confirm that blast-furnace performance is not always improved when the gas pressure in the furnace is increased as a result of artificial drag in the gas-supply network. What is important is not simple increase in the gas pressure but optimization of this pressure and also the total pressure difference in the furnace in specific operating conditions.

Systematic Prioritization of Sensor Improvements in an Industrial Gas Supply Network

The paper analyzes the impact of the sensor reading errors on parameters that affect the production costs of a leading US industrial gas supply company. For this purpose, a systematic methodology is applied first to determine the relationship between the system output and input parameters and second to identify the assigned input sensors whose readings need to be improved in a prioritized manner based on the strength of those input-output relationships. The two main criteria used to prioritize these sensors are the decrease in production costs and the decrease in production costs’ volatility obtained when the selected sensor’s precision is improved. To illustrate the effectiveness of the proposed approach, we first apply it to a simplified version of the real supply network model where the results can be readily validated with the simulated data. Next, we apply and test the proposed approach in the real supply network model with historical data.

Benefits of demand-side response in combined gas and electricity networks

Active demand side response (DSR) will provide a significant opportunity to enhance the power system flexibility in the Great Britain (GB). Although electricity peak shaving has a clear reduction on required investments in the power system, the benefits on the gas supply network have not been examined. Using a Combined Gas and Electricity Networks expansion model (CGEN+), the impact of DSR on the electricity and gas supply systems in GB was investigated for the time horizon from 2010 to 2050s. The results showed a significant reduction in the capacity of new gas-fired power plants, caused by electricity peak shaving. The reduction of gas-fired power plants achieved through DSR consequently reduced the requirements for gas import capacity up to 90 million cubic meter per day by 2050. The cost savings resulted from the deployment of DSR over a 50-year time horizon from 2010 was estimated to be around £60 billion for the GB power system. Although, the cost saving achieved in the gas network was not significant, it was shown that the DSR will have a crucial role to play in the improvement of security of gas supply.

Adaptive Modelling, Simulation and Optimization of Gas and Water Supply Networks

AbstractWe consider the simulation and optimisation of transport processes through gas and water supply networks. Using a consistent modeling of the network, adjoint equations for the whole system including initial, coupling and boundary conditions can be derived. These are suitable to compute gradients for optimization tasks but can also be used to estimate the accuracy of models and the discretization with respect to a given cost functional. We show the applicability of an adaptive algorithm that automatically steers the discretization and models while maintaining a given accuracy in an optimisation framework. (© 2016 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Artificial earthquake test of gas supply networks

In this paper, seismic behavior of gas supply networks is investigated by constructing a 24m×24m buried network and conducting an artificial earthquake test by detonating TNT explosives. The pipe network consists of typical welded steel pipes used in gas supply networks. Ground motion is produced by detonating 30kg of TNT explosives buried 5m below ground surface and 15m away from the network. The test preparations are presented, including site selection, network layout, ground motion generation, and arrangements of different sensors. The measured ground acceleration, strain, and acceleration of welded steel pipes, and pipe–soil relative slippage are discussed. The deformation patterns of welded steel pipes are also analyzed and explained, including axial and bending deformations, systematic network characteristics, deformation relationship between ground and pipes, and dynamic response of buried pipes.

A multi vector energy analysis for interconnected power and gas systems

This paper presents the first multi vector energy analysis for the interconnected energy systems of Great Britain (GB) and Ireland. Both systems share a common high penetration of wind power, but significantly different security of supply outlooks. Ireland is heavily dependent on gas imports from GB, giving significance to the interconnected aspect of the methodology in addition to the gas and power interactions analysed. A fully realistic unit commitment and economic dispatch model coupled to an energy flow model of the gas supply network is developed. Extreme weather events driving increased domestic gas demand and low wind power output were utilised to increase gas supply network stress. Decreased wind profiles had a larger impact on system security than high domestic gas demand. However, the GB energy system was resilient during high demand periods but gas network stress limited the ramping capability of localised generating units. Additionally, gas system entry node congestion in the Irish system was shown to deliver a 40% increase in short run costs for generators. Gas storage was shown to reduce the impact of high demand driven congestion delivering a reduction in total generation costs of 14% in the period studied and reducing electricity imports from GB, significantly contributing to security of supply.

Quantification and Enhancement of the Resilience of Infrastructure Networks

AbstractIn this paper, network resilience is quantified by generalization of various notions used in the mathematical theory of network resilience. This algorithm is then used to create a quantitative framework for the resilience characterization of high-pressure natural gas networks. The key concepts are the notions of a network with associated delivery function and delivery importance. No model is available in the literature to measure the performance of high-pressure natural gas networks. In this paper, a new index measuring delivery importance of a gas network is proposed to evaluate the resilience of the entire network. The methodology can be used to consider and quantify the effects of any type of natural disasters such as earthquake and fire, or artificial hazards such as deliberate attacks on the system that may lead to the disruption of the system. The principles and theories applied to the natural gas supply and distribution network in this study can also be applied to other infrastructures that...

Day-ahead coordinated operation of utility-scale electricity and natural gas networks considering demand response based virtual power plants

The steady-state coordinated operation of electricity networks and natural gas networks to maximize profits is investigated under market paradigm considering demand response. The components in its gas supply networks are modeled and linearized under steady-state operating conditions where combined cycle gas turbine (CCGT) generators consume natural gas and offer to the electricity market. Interruptible-load based and coupon-based demand response virtual power plants are considered trading in the market like physical generators. A bi-level programming optimization model is formulated with its upper-level representing the coordinated operation to maximize profits and its lower-level simulating the day-ahead market clearing process. This bi-level problem is formulated as a mathematical program with equilibrium constraints, and is linearized as a mixed-integer programming problem. Case studies on a 6-bus power system with a 7-node natural gas system and an IEEE 118-bus power system with a 14-node gas system verify the effectiveness of the coordinated operation model. The impacts of demand response based virtual power plants on the interactions between the two networks are also analyzed.

Technical-urbanistic infrastructure in the Romanian Danube Valley: Urban vs. rural territorial disparities

Infrastructure, particularly technical one, is basis of economic activities both in urban and rural areas. The Romanian sector of the Danube Valley covers a large area, in which the life of resident communities is shaped by the River (1,075 km long). At present, 266 local administrative units (LAU2) in the Romanian Danube Valley number 238 communes, 28 municipia and towns and a population of 1.7 million inhabitants. The study relies on the data provided by the National Institute of Statistics, the results of the Population and Housing Census (2011) and TEMPO Online Database (Internet 1). Hierarchizing LAU2 in terms of the technical-urbanistic infrastructure was made by the Hierarchical Ascending Classification (HAC). The aim was to group together territorial-administrative units by their parametric variables. There are many Danube Valley communities still unconnected to local drinking-water and sewerage systems, a restrictive factor in drawing potential investments into local economies. The study points out that the large Danubian port-cities also have the longest water and natural gas supply networks, as well as the greatest proportion of dwelling-houses connected to these systems. A fairly good situation have also some rural settlements lying close to big municipia or to tourist towns (in Danube Gorge and Danube Delta).