Gas Supply System Research Articles

PEMFC Gas-Feeding Control: Critical Insights and Review

Proton exchange membrane fuel cells (PEMFCs) are currently a relatively mature type of hydrogen energy device due to their high efficiency and low noise compared to traditional power devices. However, there are still challenges that hinder the large-scale application of PEMFCs. One key challenge lies in the gas supply system, which is a complex, coupled nonlinear system. Therefore, an effective control strategy is essential for the efficient and stable operation of the gas control system. This paper aims to provide a comprehensive and systematic overview of the control strategies for PEMFC anode and cathode supply systems based on an analysis of 182 papers. The review covers modern control theories and optimization algorithms, including their design, objectives, performance, applications, and so on. Additionally, the advantages and disadvantages of these control methods are thoroughly evaluated and summarized.

CHARACTERISTICS OF THE DEVELOPMENT OF THE GAS SUPPLY SYSTEM IN THE REPUBLIC OF ARMENIA

Gas distribution and transportation networks make up the gas supply system. Providing natural gas to the public and the economy is the primary objective of the gas delivery system. Every nation's gas supply network is strategically vital since the cost of natural gas directly impacts the goods and services that are produced and rendered there. It is true that developed nations are looking for innovative technology for natural gas extraction because it is a non-renewable resource. Founded during the Soviet era and throughout multiple phases of development, the Republic of Armenia's gas supply system is a component of the worldwide network. The Public Services Regulatory Commission and the Armenian government, through the Ministry of Territorial Administration and Infrastructure, oversee the country's gas supply industry. The article discusses the Republic of Armenia's domestic natural gas market's supply and sales, its background and present state, investment initiatives, and features that increase the system's operational efficiency.

Microheater Controlled Crystal Phase Engineering of Nanowires Using In Situ Transmission Electron Microscopy

AbstractCrystal Phase Quantum Dots (CPQDs) offer promising properties for quantum communication. How CPQDs can be formed in Au‐catalyzed GaAs nanowires using different precursor flows and temperatures by in situ environmental transmission electron microscopy (ETEM) experiments is studied. A III‐V gas supply system controls the precursor flow and custom‐built micro electro‐mechanical system (MEMS) chips with monocrystalline Si‐cantilevers are used for temperature control, forming a micrometer‐scale metal–organic vapor phase epitaxy (µMOVPE) system. The preferentially formed crystal phases are mapped at different precursor flows and temperatures to determine optimal growth parameters for either crystal phase. To control the position and length of CPQDs, the time scale for crystal phase change is investigated. The micrometer size of the cantilevers allows temperature shifts of more than 100 °C within 0.1 s at the nanowire growth temperature, which can be much faster than the growth time for a single lattice layer. For controlling the crystal phase, the temperature change is found to be superior to precursor flow, which takes tens of seconds for the crystal phase formation to react. This µMOVPE approach may ultimately provide faster temperature control than bulk MOVPE systems and hence enable engineering sequences of CPQDs with quantum dot lengths and positions defined with atomic precision.

Analysis of the Possibilities of Energy Supply to Consumers in Cold Conditions During Large-Scale Emergency Installations in the Gas Industry

The article presents the main components of the methodological approach to the analysis of the possibilities of supplying final types of energy to consumers in the event of a loss of performance of critical facilities of the Russian gas industry in conditions of cooling in the territories of the federal districts. The principle of choosing a territorial section for analyzing the situation with a simultaneous increase in demand for fuel and energy resources is described. An algorithm for conducting research is given. Research is carried out by modeling the work of the country’s fuel and energy complex during the period of the average day of January in the conditions of a peak-increasing demand for thermal energy in the territories of federal districts. At the same time, the cooling is modeled in turn for each of the federal districts in the zone of operation of the Unified Gas Supply System of Russia. An analysis of the possibilities of meeting the demand for final types of energy in the constituent entities of the Russian Federation is carried out for all key scenarios of cooling and loss of efficiency of critical gas industry facilities. The principles of modeling the situation with the supply of final types of energy to consumers in these situations are shown. The most vulnerable regions under the analyzed conditions are identified. The conclusion is made about the need for a balanced approach to determining the optimal degree of dominance of natural gas in the fuel and energy balance of the regions, taking into account the existing opportunities for its supply in the conditions of large-scale emergencies in the gas industry.

MATHEMATICAL MODELS OF THE THERMAL PROTECTION COATING OF THE GAS GENERATOR OF THE HYDROGEN STORAGE AND SUPPLY SYSTEM

The article describes the properties of the thermal protection coating of the gas generator of the hydrogen storage and supply system by two transfer functions with Hurwitz polynomials of the third order. Obtaining such transfer functions is based on the solution of the non-stationary heat conduction equation, represented in operator form using the integral Laplace transform, and in which approximating spline functions in the form of second-order polynomials are used. The article gives the solution of the non-stationary thermal conductivity equation, which describes the thermal processes in the heat-protective coating of the gas generator of the hydrogen storage and supply system under the thermal effect of a fire. This solution comes in the operator form for the surface temperature of the heat-protective coating on the side of the gas generator wall. The peculiarity of this decision is the presence of hyperbolic functions of an irrational argument in its composition. The structural and dynamic scheme of the thermodynamic system ‘gas generator wall – heat-protective coating’ is presented, the feature of which is the presence of two entrances. The signal at the scheme’s first input reflects the thermal effect of the fire, and the signal at the second input reflects the thermal state of the gas generator cavity. An equivalent mathematical transition to the description of thermal processes in the heat-protective coating of the gas generator of the hydrogen storage and supply system was carried out. This transition happened due to the use of spline functions, which approximate the hyperbolic functions of the irrational argument and are polynomials of the second order. The article gives a verbal interpretation of the algorithm for determining the transfer functions of the heat-protective coating of the gas generator of the hydrogen storage and supply system and also an example of its implementation. Furthermore, it shows that for the given conditions of functioning of the gas generator heat-protective coating, the relative errors in approximation of hyperbolic functions by second-order polynomials do not exceed 1.7 %, and the average relative error when equivalent replacement of transfer functions does not exceed 3.8 %. Keywords: gas generator, hydrogen storage and supply system, thermal protection coating.

Experiment-based feasibility study of LNG equipment-embedded fuel gas supply system for vessels

This study introduces and validates an innovative Liquefied Natural Gas (LNG) Equipment-Embedded Fuel Gas Supply System (LEEF) designed for small LNG-fueled vessels. These ships face significant challenges in implementing LNG Fuel Gas Supply Systems (FGSS) owing to limited space and stringent regulatory requirements to reduce Greenhouse Gas (GHG) emissions. The LEEF system addresses these challenges by replacing the external Pressure Build-up Unit (PBU) with an integrated in-tank Electric PBU (EPBU) and vaporizer, enhancing spatial efficiency and safety while reducing LNG leakage risks. The experimental results indicate that the Pressure Rise Rate (PRR) accelerates with higher tank levels and increases the EPBU power. The PRR doubled at higher liquid levels and improved by 30–44 % with increased EPBU power at a constant liquid level. The EPBU effectively maintained the tank pressure against flow variations, achieving pressure control with minimal power. A review of international regulations and codes confirms that the EPBU satisfies explosion-proof standards and ensures stable operation. The LEEF system demonstrated substantial potential for application in small LNG-fueled ships by combining improved spatial efficiency and enhanced safety. This study contributes to the development of the FGSS solution that is more compact and safer compared to conventional systems, encouraging sustainable marine propulsion.

Novel Gas Supply System for Multi-Chamber Tri-Gas Cell Culture: Low Gas Consumption and Wide Concentration Range

Gas plays a crucial role in cell culture as cells require a specific gas environment to maintain their growth, reproduction, and function. Here, we propose a gas supply system for tri-gas multi-channel cell incubators to meet the specific needs of various cells. The system utilizes a circulating gas supply method powered by air pumps for each chamber. Gas inflow from the cylinder is independently controlled by Mass Flow Controllers (MFCs), and a quantitative step-by-step adjustment control strategy is employed to calculate the volume of different gases being introduced. Through mixing simulations and experiments, we identified the SV static mixer with an L/D ratio of 2.5 as the optimal choice. To evaluate the concentration accuracy and gas consumption of the gas system, we conduct gas mixing and distribution experiments under different conditions. The results show that the system could achieve a concentration range of 0–100% for O2 with an accuracy of ±0.5%, and a concentration range of 0–10% for CO2 with an accuracy of ±0.1%. The daily gas consumption during cultivation is 3570 mL of N2, 330 mL of CO2, and 115 mL of O2, significantly lower than conventional incubators. Overall, our system can effectively manage dynamic gas concentration changes, particularly in high O2 concentration environments. It offers advantages such as low gas consumption, a wide concentration range, and high accuracy compared to existing incubators.

APPLICATION OF THE METHOD OF GROUP ARGUMENTS ACCOUNTING FOR BUILDING MODELS OF SHORT-TERM FORECASTING OF GAS CONSUMPTION BY THE POPULATION

Problem statement. One of the most important tasks in optimizing the operation modes of urban gas distribution systems is to develop a short-term strategy for such modes. Processing of planned and statistical indicators of gas consumption modes is one of the key methods for ensuring the optimal functioning and normal operation of gas supply systems. The most promising modeling method for solving forecasting problems is the method of self-organization of models implemented as the method of group arguments accounting (MGАA). Short-term forecasting of gas consumption is the main source of information for decision-making in the process of planning consumption regimes and operational dispatch control. The MGАA method, also known as the Ivakhnenko method, is a powerful tool for obtaining highly accurate forecasting models and is gaining importance for forecasting in energy resource management and planning their use. The solution to such a problem is relevant, as it makes it possible to analyze the volume of natural gas consumption by the population for the future period. The purpose of the article is to build mathematical models for forecasting gas consumption using the method of group arguments accounting based on input data. Conclusion. To select the best models the following parameters are recommended: tomorrow's gas consumption as a function (main criterion) and arguments (additional criterion) - gas consumption to date, air temperature to date, yesterday's temperature and temperatures for the past 3, 5, 7 days, wind speed and day of the week. The resulting mathematical models of natural gas consumption by the population can be used to analyze the volume of natural gas consumption. The method allows us to find a single optimal mathematical model that best solves the problem.

Modelling of an Influence of Liquid Velocity Above the Needle on the Bubble Departures Process

Abstract In the present paper, the influence of liquid flow above the needle on a periodic or chaotic nature of the bubble departures process was numerically investigated. During the numerical simulations bubbles departing from the needle was considered. The perturbations of liquid flow were simulated based on the results of experimental investigations described in the paper [1]. The numerical model contains a bubble growth process and a liquid penetration into a needle process. In order to identify the influence of liquid flow above the needle on a periodic or chaotic nature of bubble departures process, the methods data analysis: wavelet decomposition and FFT were used. It can be inferred that the bubble departure process can be regulated by altering the hydrodynamic conditions above the needle, as variations in the liquid velocity in this area affect the gas supply system’s conditions. Moreover, the results of numerical investigations were compared with the results of experimental investigation which are described in the paper [2]. It can be considered that, described in this paper, the numerical model can be used to study the interaction between the bubbles and the needle system for supplying gas during the bubble departures from two needles, because the interaction between the bubbles is related to disturbances in the liquid flow above the needle.

A Nonlinear Active Disturbance Rejection Feedback Control Method for Proton Exchange Membrane Fuel Cell Air Supply Subsystems

The control strategy of the gas supply subsystem is very important to ensure the performance and stability of the fuel cell system. However, due to the inherent nonlinear characteristics of the fuel cell gas supply subsystem, the traditional control strategy is mainly based on proportional integral (PI) control, which has the disadvantages of large limitation, large error, limited immunity, and inconsistent control performance, which seriously affects its effectiveness. In order to overcome these challenges, this paper proposes an optimal control method for air supply subsystems based on nonlinear active disturbance rejection control (ADRC). Firstly, a seven-order fuel cell system model is established, and then, the nonlinear ADRC and traditional PI control strategies are compared and analyzed. Finally, the two strategies are simulated and compared. The validation results indicate that the integral absolute error (IAE) measure of PI control is 0.502, the integral square error (ISE) measure is 0.1382, and the total variation (TV) measure is 399.1248. Compared with the PI control, the IAE and ISE indexes of ADRC were reduced by 61.31% and 58.03%, respectively. ADRC is superior to PI control strategy in all aspects and realizes the efficient adjustment of the system under different working conditions. ADRC is more suitable for the nonlinear characteristics of the gas supply system and is more suitable for the oxygen excess ratio (OER).

Oxygen excess ratio feedforward control based on ESO for PEMFC in DC off-grid hydrogen production systems

Oxygen excess ratio (OER), which is influenced by the air flow input to the cathode, is one of the important factors affecting the performance of fuel cell system. Insufficient oxygen supply will result in a sharp drop in output voltage, while an excessive supply will bring about a large parasitic power load on the air compressor, reducing the net output power of the system and operating efficiency. Both insufficient and excess oxygen supply can adversely affect the operating life of the proton exchange membrane fuel cell (PEMFC). Due to the serious nonlinear, hysteresis, uncertainty and interference in the process of OER control, this paper proposes an OER feedforward control based on extended state observer (ESO) for a PEMFC auxiliary system with the ESO to predict the total disturbance to improve the dynamic response of the system with large time delay utilizing terminal sliding mode control (TSMC). The control strategy is divided into two stages. The first stage constructs an ESO to realize real-time observation of the state variables required for the internal operation of the auxiliary machine system and the PEMFC, and yields the air compressor voltage control signal through terminal sliding mode control. In the second stage, combined with V/f control for the compressor, the transmitted air flow is adjusted, ultimately achieving the goal of changing the OER of the PEMFC and improving operating efficiency. The simulation results show that the proposed control strategy has good anti-interference capabilities, a faster response, and less overshoot. The gas flow transmission in the gas supply system is more robust, the PEMFC operation is safer, and its lifespan is extended.

Research Progress on Gas Supply System of Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) are attracting attention for their green, energy-saving, and high-efficiency advantages, becoming one of the future development trends of renewable energy utilization. However, there are still deficiencies in the gas supply system control strategy that plays a crucial role in PEMFCs, which limits the rapid development and application of PEMFCs. This paper provides a comprehensive and in-depth review of the PEMFC air delivery system (ADS) and hydrogen delivery system (HDS) operations. For the ADS, the advantages and disadvantages of the oxygen excess ratio (OER), oxygen pressure, and their decoupling control strategies are systematically described by the following three aspects: single control, hybrid control, and intelligent algorithm control. Additionally, the optimization strategies of the flow field or flow channel for oxygen supply speeds and distribution uniformity are compared and analyzed. For the HDS, a systematic review of hydrogen recirculation control strategies, purge strategies, and hydrogen flow control strategies is conducted. These strategies contribute a lot to improving hydrogen utilization rates. Furthermore, hydrogen supply pressure is summarized from the aspects of hybrid control and intelligent algorithm control. It is hoped to provide guidance or a reference for research on the HDS as well as the ADS control strategy and optimization strategy.

Multiphase-Thermal Flow Simulation in a Straight Vacuum-Insulated LH2 Pipe: Fuel Gas Supply System in a LH2-Fueled Ship

Hydrogen, stored as a liquid at cryogenic temperatures to enhance transport efficiency, is susceptible to boiling due to thermal fluctuations, underscoring the importance of investigating thermal insulation for liquid hydrogen piping. Evaluating their suitability and effectiveness for hydrogen ship piping remains critical. This study conducted numerical simulations to analyze insulation and phase-change impacts on the multiphase thermal flow of piping systems used for the Fuel Gas Supply System (FGSS) of hydrogen-fueled ships. The accuracy of the adopted phase-change model was validated against selected experimental cases of boiling phenomena, demonstrating agreement with experimental results. We applied the validated phase-change model to simulate multiphase thermal flow in an LH2 pipe and evaluated the thermal performance of insulation materials. The insulation material considered in this study is a composite insulation system with various filling materials. Specifically, we observed that the insulation performance was superior when utilizing a combination of vacuum insulation along with MLI Mylar nets. Additionally, we evaluated the safety within the pipe by comparing the amount of vapor generated inside with the Lower Flammability Limit (LFL). Our results indicate that a safety assessment of the insulation is necessary when no filling material is used. Quantitatively, we found that pipes with composite vacuum and MLI Mylar net insulation reduced vapor generation by 45% compared to vacuum-only insulation, highlighting the effectiveness of the proposed insulation method.

Considering the reliability of gas supply to power plants in the analysis of electric power system adequacy

One of the promising directions for further development of the methodology for investigating and ensuring the reliability of energy systems is the consideration of integrated energy systems. This is caused by the need for the adequate reflection of their joint operation. Previously, the authors proposed several methodological approaches based on "node," "system," and "evaluation" to assess the adequacy of an electric power system when this is operating jointly with a gas supply system. In that case, the focus was made only on high-pressure gas supply systems (simplified calculation). This work aims to consider not only the high-pressure gas systems, but also to take into account the influence of lowpressure gas systems (refined calculation) on the adequacy of electric power system. This approach appears to be more technologically advanced and corresponds to the real conditions of the functioning of integrated power systems. The studies were carried out using the “node” approach, its reference calculation being the most accurate one. The methods applied in the research are probability theory and mathematical statistics: a particular theorem on the repetition of experiments (Bernoulli's trial), calculation of probability distribution series, theorems of addition and multiplication of probabilities. A comparative analysis of reference calculations of the electric power system adequacy was carried out for simplified and refined connection schemes in the gas system (two cases were considered: a highly reliable low-pressure gas system and a low-reliability one). The calculations were performed on an illustrative example of a power system. Assessment of the load supply reliability in integrated systems must factor in the process features of the systems at issue, the block diagram of their connections, as well as the accuracy of the results obtained and the complexity of searching and preparing initial data for the corresponding research model.

Modern Theoretical and Practical Protection Methods of Metallic Structures Against the Effects of Corrosion

Abstract The problems of corrosion and anti-corrosion protection are currently an important area for preventing economic losses and combating environmental pollution. Corrosion-related problems are present in all economic fields, including machine construction, shipbuilding and port construction, chemistry and petrochemicals, metallurgy, water and gas supply systems, energy production systems, transports, etc. Corrosion is a complex process that depends on many factors, related to the variety of technical metal materials and technological environments. This paper can be considered a mini-review that contains some general theoretical aspects related to the corrosion of metals and some case studies from the specialized literature of the last five years, in the field of various technical and industrial constructions based on metal structures.

Robust optimization of transactive flexibility oriented scheduling of joint electricity and gas supplies

The power system with flexibility provision will lead to the expansion of the utilization of renewable energy resources. Providing flexibility is one of the basic challenges for power system operators and developers, which is addressed in this study. Moreover, the security of the gas supply system is important for power system operators, because the operation of gas-fired units depends significantly on the gas supply. In this study, the availability of pipelines has been considered as a gas supply uncertainty. Then, an optimal uncertainty set is proposed for security constraint unit commitment (SCUC) which is calculated for managing the uncertainty of wind and gas supply in different scenarios of risk. Robust-based optimization has been implemented to obtain the optimal uncertainty set in which both feasibility and economic optimal robustness have been guaranteed. A new robust flexibility-based SCUC model has been applied using a demand response program (RFSCUCDRP). The transactive flexibility between flexible providers, such as thermal units and DR, and uncertainty producers, such as wind resources, has been determined in the proposed model. The problem has been implemented on the 6-bus and IEEE-118-bus standard test systems with different risk percentages. The operation costs of the 6-bus system with and without robust optimization are 89,094 $ and 119,475 $, respectively. It is concluded that robust optimization is ultimately economically better.

A Study on hydrogen dispersion characteristics according to the length of the exhaust duct in the fuel gas supply system room

A Study on hydrogen dispersion characteristics according to the length of the exhaust duct in the fuel gas supply system room

ОБОСНОВАНИЕ ПРИМЕНЕНИЯ КОМПОЗИТНЫХ БАЛЛОНОВ В КОММУНАЛЬНО-БЫТОВОМ ОБЕСПЕЧЕНИИ ПОТРЕБИТЕЛЕЙ ГАЗОМ

The introduction of new advanced materials into gas supply practice leads to the creation of new products with improved qualities. For domestic use, along with traditional metal cylinders for liquefied petroleum gas, composite cylinders have recently been offered. Possessing a number of undeniable advantages, composite cylinders annually increase their share of presence in the field of bottled gas supply. However, the transition from traditional metal cylinders for the consumer should not be accompanied by a banal change of vessels, but requires a comprehensive, competent approach with justification for decisions made on the formation of a gas supply system for the consumer based on cylinders made of composite materials. Using the basic principles characterizing changes in the states of gas mixtures included in liquefied hydrocarbon gas, the characteristics of heat exchange, the vessels under study, the principles of operation of gas-using equipment for the consumer, parameters are determined that form the basis for the competent use of composite cylinders for the consumer using liquefied gases of various brands. As a result of the research, the mass of gas for filling cylinders was determined, taking into account the seasonality of operation and brands recommended for domestic consumption, the process of heat exchange between the cylinder and the environment was studied, taking into account its operating mode and the uneven generation of the vapor phase in the daily cycle of operation to ensure food preparation and hot water supply to consumers, the optimal periods of continuous operation of an individual cylinder installation with different capacities of a sin-gle composite cylinder and the number of cylinder replacements in the annual operating cycle were determined.

Experimental studies of air ozonization influence on pollutants emission in vortex ignition-stabilizing modules of gas turbine combustion chambers

Reduction of pollutant emissions into the atmosphere is an urgent task of modern gas turbine engineering development. Such substances that have a negative impact on the environment include nitrogen oxides and carbon monoxide. The article provides a review of the existing methods for reducing the emissions of pollutants used in the combustion of hydrocarbon fuels in the combustion chambers of gas turbine units, as well as indicates promising technologies developed based on these methods. Justification is presented of the necessity to study the method of ozonization of air supplied to the fuel combustion zone to reduce the content of pollutants in its combustion products. The purpose of the study was to develop recommendations for reducing pollutant emissions within a given range of variations regime parameters. To perform the necessary set of experimental studies, a specialized laboratory stand was created, the combined circuit and measurement scheme of which is given in the article. A rather detailed description is given of the structural elements of the stand and, in particular, of the subject of research — a full-scale vortex ignitionstabilizing module of the combustion chamber of a gas turbine unit, an electric ozonator, air and combustible gas supply systems, an exhaust system with a central fan, control and measuring instruments and fittings. The tests were carried out in accordance with specially developed methods of controlling the stand operation in three modes: startup; transfer from one steady-state mode to another; stop. The influence of air ozonization on combustion processes in the vortex ignition-stabilizing module was determined by the content of nitrogen oxides and carbon monoxide in it. The factors that influence the decrease in the concentration of carbon monoxide in the combustion products during the combustion of air in ozonized air have been determined. The methods of calculation determination of combustible gas and air parameters — mass flow rates, flow velocities and dynamic heads — are described. The results of the performed experimental studies are presented in graphical interpretation, their detailed analysis is given, on the basis of which recommendations on practical use of the method of air ozonization are given.

Long-term planning and coupling optimization of multi-regional natural gas and hydrogen supply systems: A case study of China

Low-carbon transition of energy systems features more natural gas and hydrogen consumption to replace coal and oil. Planning of natural gas and hydrogen supply systems with multiple supply sources, end-consumers, large infrastructures and spatio-temporal mismatches are challenging tasks. In this study, two long-term, multi-regional and monthly time-scale optimization models for natural gas and hydrogen supply systems are developed respectively. China is taken as a case. The natural gas demand will initially increase and then decrease, leading to a premature decommissioning of infrastructure. A coupling model is established to explore the retrofitting of decommissioned natural gas infrastructure for hydrogen supply. Results show that 44.14 % decommissioned pipelines and 34.17 % decommissioned storage facilities of natural gas supply system can be retrofitted, with an annual increase of 63.98 % and 62.80 % in hydrogen pipelines and storage facilities, and a 9.15 % reduction in transition costs.