Gas Volume Research Articles

The Impact of Autonomous Inflow Control Valve on Improved Oil Recovery in a Thin-Oil-Rim Reservoir

Summary Oil production from thin-oil-rim fields can be challenging as such fields are prone to gas coning. Excessive gas production from these fields results in poor production and recovery. Hence, these resources require advanced recovery methods to improve the oil recovery. One of the recovery methods that is widely used today is advanced inflow control technology such as autonomous inflow control valve (AICV). AICV restricts the inflow of gas in the zones where breakthrough occurs and may consequently improve the recovery from thin-oil-rim fields. This paper presents a performance analysis of AICVs, passive inflow control devices (ICDs), and sand screens based on the results from experiments and simulations. Single- and multiphase-flow experiments are performed with light oil, gas, and water at typical Troll field reservoir conditions (RCs). The obtained data from the experiments are the differential pressure across the device vs. the volume flow rate for the different phases. The results from the experiments confirm the significantly better ability of the AICV to restrict the production of gas, especially at higher gas volume fractions (GVFs). Near-well oil production from a thin-oil-rim field considering sand screens, AICV, and ICD completion is modeled. In this study, the simulation model is developed using the CMG simulator/STARS module. Completion of the well with AICVs reduces the cumulative gas production by 22.5% and 26.7% compared with ICDs and sand screens, respectively. The results also show that AICVs increase the cumulative oil production by 48.7% compared with using ICDs and sand screens. The simulation results confirm that the well completed with AICVs produces at a beneficial gas/oil ratio (GOR) for a longer time compared with the cases with ICDs and sand screens. The novelty of this work is the multiphase experiments of a new AICV and the implementation of the data in the simulator. A workflow for the simulation of AICV/ICD is proposed. The simulated results, which are based on the proposed workflow, agree with the experimental AICV performance results. As it is demonstrated in this work, deploying AICV in the most challenging light oil reservoirs with high GOR can be beneficial with respect to increased production and recovery.

Coal mine methane utilization as a component of the complex mining concept in the context of conversion into thermal and electrical energy

The paper deals with multi-component complex mining of mineral raw materials in the context of sustainable development and its important component – coal mine methane utilization and its conversion into thermal and electrical energy. The conducted analysis of scientific and practical experience has shown the multi-parameter nature of this process and the influence of a large number of factors. The mining-geological conditions of the Western Donbas (Ukraine) are substantiated as the research object, which makes it possible to limit the variation of geomechanical factors, as well as to develop basic provisions and general principles for reasoning predictive assessments of outgassing during complete mining of coal reserves. The dependence of gas volume on specific gas content of lithotypes and the volume of their destruction related to the coal-bearing stratum shear mechanisms at different options of complete mining of the Western Donbas coal reserves, is presented. The patterns of influence of the main geomechanical factors on the propagation of disturbed rock zones are substantiated.

Research on the Load Characteristics of Squeezed Film Gas Bearings

In this paper, a gas microbody is proposed to address the issues related to the limited load‐carrying capacity of squeezed film gas bearings, complex mechanical structures, large overall dimensions, high manufacturing costs, and complicated installation. Initially, the gas continuity equation of squeezed film was established for modal analysis, without regard to the gas inertial force and the gas volume force which are all far less than the gas viscous force. Then the load‐carrying characteristics of squeezed film gas bearing were studied and analyzed with the fluid‐structure coupling method. The load‐carrying capacity of the squeezed film gas bearing is determined by factors such as bearing amplitude, rotor‐axial clearance, and rotor‐axial tile contact area. In conclusion, the load‐carrying capacity can be enhanced by increasing the amplitude value, reducing the clearance, and increasing the contact area. Among them, when adjusting the amplitude and clearance to improve the bearing’s load‐carrying capacity, the stability of bearing operation should be considered. When the clearance is too small, the pressure distribution of the air film will be uneven, and when the contact area is too large, the development of the air film in all directions will be asymmetrical.

Re-evaluation of the Hydrocarbon Potential of the Scarborough Field, Offshore Northern Carnarvon Basin, Australia.

This study examines the detailed basin analysis and re-evaluation of the hydrocarbon potential of the Scarborough Field in the Northern Carnarvon Basin, offshore Australia, aiming to enhance energy reserves. The research integrates extensive datasets, including a 3-D seismic reflection volume, fifty-two 2-D seismic lines, well logs from six wells, checkshot surveys, and surface geologic maps. The Northern Carnarvon Basin, a significant hydrocarbon reserve in Australia, has experienced a multi-phase extensional history and exhibits a complex stratigraphy linked to six tectonic phases. The pressing need for increased energy reserves necessitates revisiting old hydrocarbon fields to boost their production capacity using integrated methods. Well-log interpretation and correlation have revealed the lateral extents of petroleum system elements. The stratigraphic analysis identified three sequences and associated system tracts using the Depositional Sequence Model IV. Structural framework interpretation highlighted faults as migration pathways and hydrocarbon traps. Time and depth structure maps were produced to identify leads and prospects. Four leads and three prospects were pinpointed using RMS amplitude surfaces. Porosity values range from 20% to 29%, with hydrocarbon saturation between 51% and 65%. Volumetric assessment indicates that NAU Deep-1 contains 10.6 bcf, NAU Deep-2 holds 4.24 tcf, and NAU Deep-3 has 6.22 tcf of gas. These significant gas volumes highlight potential for future exploration and development in the Scarborough sedimentary infill.

IMPROVED LEVEL OF TECHNOGENIC SAFETY IN PLANTS INTENDED MUNICIPAL SOLID WASTE INCINERATION

Solid municipal waste can be an alternative and renewable type of fuel. Waste incineration provides effective disposal, significant volume reduction and utilization of the energy potential of the carbon waste part. In order to protect the components of the biosphere and service personnel from harmful substances that are formed in the furnace space, it is first necessary to assess the chemical composition and volume of emissions. The purpose of the work is to study the process of burning municipal waste, determine the heat energy obtained, determine the amount of air required for the complete combustion reaction, and determine the volume of flue gases produced as a result of combustion. To achieve the goal of the research, a complex of methods of system analysis and the method of data analysis was applied. An analysis of modern international literary sources, an analysis of the morphological composition of the combustible part of solid household waste, and an analysis of the interaction of chemical substances was carried out. For the research, several components of waste were collected, which were conditionally divided into two main groups - paper and plastic. The first group includes waste, which includes wood, cardboard, and paper. The second group (plastic) includes waste, which includes plastic in the form of scraps of polyethylene film, disposable dishes. As a result of the research, a theoretical volume of combustion products was obtained for the further design of the system of protection of the environment and service personnel from emissions of thermal disposal of solid household waste. Research results can be used in the design of municipal waste incineration equipment. The system of using the heat of flue gases generated after burning waste to dry the waste before feeding it to the furnace is of great importance for saving additional fuel.

Invitro Fermentation of West African dwarf (wad) goats fed treated Rice husk as Wheat bran substitute

ABSTSRACT The study was conducted to evaluate the in vitro fermentation characteristics of West African Dwarf goat fed treated rice husk as wheat bran substitute. A total of 20 growing West Africa Dwarf goats were subjected to five dietary treatments in a completely randomized design with 4 animals per replicate. The treatments are: 0% RH (T1), 25% RH (T2), 50% RH (T3), 75% RH (T4) and 100% RH (T5). The animals were fed at 5% of their body weight. The result showed that T2 and T1 are relatively high in crude protein, low in crude fiber, moderate in crude fat and high in carbohydrate. They equally had the lowest values of ADF, ADL and NDF among the treatments. The gas volume produced under each treatment continue to increase at every three hours. The production of gas was significantly (P<0.05) influenced by the incubation period and that T1 produced more gas followed by treatment T2 and then T3 and T4 while T5 had the least gas production. Methane (CH4) production was least in goats fed T4, followed by goat fed T1 while those on T2, T3 and T5 produced the highest and same methane gas quantities. In conclusion, treated rice husk as a substitute for wheat bran at 25 and 75% inclusion level gave better in-vitro fermentation performance in the goat. Key words: Treated rice husk, WAD goat, weigh gain, feed conversion ratio, feed intake

Using a model of zonal drainage of an artificial gas deposit for analytical control of gas volumes in reservoirs of UGS

One of the main tasks of the analysis of gas storage in aquifers-reservoirs is the operational control of drained volumes of gas, the value of which largely depends on the technological and technical and economic indicators of the creation and operation of UGS. An effective tool for solving this problem is the use of gas-hydrodynamic proxy models of formations. One of such models is presented, which, taking into account the implemented system of group (by assembly points) placement of vertical production wells, can be briefly described as a model of zonal drainage and seasonal interzonal gas flows in the reservoir. An example of calculations of changes in the cyclic operation of UGS of gas-saturated pore volumes and gas volumes in different drained zones, including in the peripheral poorly controlled zone of the formation, taking into account seasonal interzonal gas flows, as well as the volumes of man-made gas accumulations in the control horizons formed as a result of interplastic flows is given.

Analysis of Noise Level with Convergent and Divergent Shape of Muffler and its Impact on Noise Pollution

Noise pollution is one of the key hazards that decreases people's quality of life globally. Due to the rapid development of technology, industrialization, urbanization, and transportation networks, noise pollution has reached serious levels in recent years. Sound transmission loss, the attenuation of sound as it passes through diverse objects and environments, is crucial in lowering noise pollution and preserving the acoustic integrity of ecosystems. Due to de-throttling tactics implemented to optimize cylinder fill, the intake system of internal combustion engines is the primary noise source while the vehicle is at low speeds and high loads. Therefore, achieving high acoustic performance of intake systems constitutes a critical issue in complying with the increasingly stringent European regulations for overall noise emission. The Transmission Loss computation is typically the most used technique for describing a system's acoustic performances. This work provided an overview of sound transmission loss and discussed its substantial environmental effects. It investigates the fundamentals of sound transmission, the factors that influence it, and the environmental impacts of sound attenuation. This paper proposed a comparison of three designs like straight duct (muffler), convergent and divergent design of muffler. The main aim is to observe sound transmission loss and compare the noise level with three muffler configurations with the same gas volume. High transmission loss indicates more noise reduction in muffler design, which will help reduce environmental noise pollution.

DUCKWEED AS A NON-CONVENTIONAL FORAGE FOR RUMINANTS IN THE TROPICS

The high cost of grain-based concentrates and crop residues are increasingly affecting profitable ruminant farming in Nigeria because of inadequate green forage all year round. Duckweeds are aquatic plants which constitute a nuisance in an earthen fish pond. However, information about their forage value is limited. Hence, this study was conducted to evaluate the nutritive value, secondary metabolites and in vitro fermentation characteristics of duckweed from earthen fish ponds. Duckweed represented as T1, T2, T3, T4 and T5 from different locations were collected, dried and analysed for chemical composition and in vitro gas production using buffered rumen fluid from goats. Cumulative gas production was measured at 3 to 48 hours of incubation periods. Results indicated that crude protein content was similar, while NDF, ADF and ADL were significantly different, with mean values of 54.11 %, 29.53 % and 11.57 %, respectively. Saponin content (0.407 − 0.468 %) was higher than alkaloids (0.312 − 0.433 %) and total phenols (0.158 − 0.175 %). Calcium and phosphorus varied from 0.09 to 0.54 % and 0.01 to 1.05 %, respectively. Lead and cadmium ranged from 0.01 to 0.17 mg.kg-1 and 0.01 to 0.03 mg.kg-1, respectively. Gas from the insoluble fraction (b), potential gas (a+b), the rate (c) and volume (Y) of gas produced were comparable. Cumulative gas produced increased as hours of incubation progressed, with gas volumes higher (3.93 mL/200 g DM) at 48 hr and least (1.07 mL/200 g DM) at 12 hr post-incubations. Metabolizable energy was similar and ranged from 3.13 to 3.68 MJ/Kg DM. Organic matter digestibility was higher (40.58 %) for T1 and comparable with T5 (36.76 %). Short-chain fatty acids (ranged = 0.02 − 0.05 µmol/200 mg DM) were comparable. In vitro dry matter degradability (ranged = 24.00 to 39.67 %) was significantly different. In conclusion, duckweed from earthen fish ponds is fairly degradable in vitro, and the nutrient contents elucidate its forage value for ruminants.

ANALYSIS OF EXTREME VALUES FOR DATA PROCESSING OF IN-LINE TECHNICAL DIAGNOSTICS

The pipeline system plays an important role in the structure of enterprises engaged in the transportation of significant volumes of oil and gas over long distances. However, steel pipelines are subject to corrosive factors, which can lead to defects and a reduced service life. Statistical analysis methods have recently been increasingly used to maintain structural reliability and ensure safe operation of equipment, both in the oil and gas industries. One method of statistical modeling is extreme value analysis, which can be used to extrapolate data from random inspection checks to non-investigated areas. The article is devoted to the assessment of the possibility of using statistical methods for analyzing data of in-line technical diagnostics (ITD) to ensure the integrity of trunk pipelines. The ITD results of one section of the export pipeline were used to determine the maximum corrosion rate of the entire length of the pipeline by extrapolating the Gumbel statistical distribution. The algorithm for constructing the Gumbel distribution is given. Plotting the autocorrelation function was used as a method for determining the independence of measurements. The belonging of the analyzed sample to the Gumbel distribution was confirmed by calculating the Anderson-Darling consent criterion. The ITD results of the remaining sections of the oil export pipeline confirmed the possibility of using extreme analysis to determine the maximum corrosion rate and increase the efficiency of pipeline inspection measures. Thus, it was concluded that statistical modeling is able to provide an estimate of the maximum corrosion rate during partial pipeline ITD and, therefore, savings in financial and time resources.

Analysis of the influence of the heat of combustion of gas on the determination of gas pipeline diameters

Natural gas plays a significant role in the energy supply structure. The country’s primary energy supply includes 29 million tons of natural gas, which accounts for 30.2 % of the country's total energy balance. Part of the biomass, combustion and output increased from 2.3 % to 11.5 %. On the other hand, the majority of gas distribution systems were put into operation thirty to fifty years ago and met the regulatory requirements in force at the time. Now, gas flows and loads in these networks have changed, and the standard service life has expired. The state of gas networks has been significantly affected by military operations. The requirements of regulatory documents in the field of gas supply have been significantly expanded in order to harmonise with the current European legislation. Calculations were introduced based on the volume of natural gas in energy units, which is determined by the higher calorific value. There are some conflicts in the national normative base, which causes the problems for gas supply design. It is proposed to use the higher heating value of gas when determining the diameter of gas networks. The use of the higher calorific value of 38.3 MJ/m3 in the hydraulic calculation of gas pipelines will allow for a more rational selection of diameters in the sections. The use of gas consumption in energy units will reduce the actual diameters of gas pipelines, their material consumption, and thus the overall cost of the system. The influence of the gas component composition on its physical and chemical properties and, as a result, on the system capacity is considered. In addition, as a result of the implementation of thermal modernisation measures in buildings, the amount of gas consumed is reduced and there is a need to optimise the values of the coefficients of simultaneous operation of gas. For today, old values are used, which are defined in 1987, when the norms of gas supply and living conditions were different. Thus, the coefficients should be adapted to the modern life and norms

Impact of Pressure and Temperature on Foam Behavior for Enhanced Underbalanced Drilling Operations.

Foam, a versatile underbalanced drilling fluid, shows potential for improving the drilling efficiency and reducing formation damage. However, the existing literature lacks insight into foam behavior under high-pH drilling conditions. This study introduces a novel approach using synthesized seawater, replacing the conventional use of freshwater on-site for the foaming system's liquid base. This approach is in line with sustainability objectives and offers novel perspectives on foam stability under high-pH conditions. Experiments, conducted with a high-pressure, high-temperature (HPHT) foam analyzer, investigate how pressure and temperature affect foam properties. The biodegradable foaming agent ammonium alcohol ether sulfate (AAES) is employed. Results demonstrate that the pressure significantly impacts foam stability. Increasing pressure enhances stability, reducing decay rates and promoting uniform bubble sizes, especially at lower temperatures. This highlights foam's capacity to withstand high-pressure conditions. Conversely, the temperature plays a substantial role in foam decay, particularly at elevated temperatures (75 and 90 °C). Decreased liquid viscosity accelerates the liquid drainage and foam decay. While pressure mainly influences the AAES foam stability at temperatures up to 50 °C, temperature becomes the dominant factor at higher temperatures. Temperature's impact on foamability is minimal under constant pressure, maintaining consistent gas volume for maximum foam height. However, foam stability is sensitive to temperature variations, with increasing temperature leading to a more significant bubble size increase gradient. These findings stress the importance of considering temperature effects in foam drilling, particularly in deep and high-temperature environments. AAES foam exhibits stability at lower temperatures, making it suitable for surface and intermediate drilling. Understanding temperature-induced changes in foam structure and bubble size is essential for optimizing performance in high-temperature and deep drilling scenarios.

Procedure for conformity assessment of automated systems for control and accounting of natural gas energy

The paper analyses the regulatory and technical requirements for the construction of automated systems for control and accounting of natural gas energy. Typical diagrams of gas energy accounting systems (gas measuring stations) are presented. Existing metrological requirements for accuracy classes in regulatory documents for the specified systems are provided. The approaches to conduct testing during the conformity assessment are considered. A procedure for conducting testing during the conformity assessment of the gas energy accounting system using a modular approach has been developed. The expediency of applying accuracy classes A, B, C and D according to DSTU EN 1776 during the conformity assessment is substantiated. The stages of testing and inspections of the installation of pressure, pressure drop, temperature, meter, flow chromatograph and energy calculator sensors are described. The necessity of using calibrated gas mixtures, the component composition of which corresponds to the transported gas, for testing the chromatograph is argued. The calculation of the maximum permissible error of the automated system for control and accounting of natural gas energy for two ranges of the gas volume flow, depending on the gas meter, is presented. The calculation under the condition of creating a new gas energy accounting system and supplementing the existing gas volume accounting system with a flow chromatograph are considered. The calculation of the error of the automated system for control and accounting of natural gas energy using the method of variable differential pressure is also presented.

Mechanical, microstructural characteristics and sustainability analysis of concrete incorporating date palm ash and eggshell powder as ternary blends cementitious materials

Cement production causes a threat to environmental sustainability owing to the enormous volume of greenhouse gas releases and high energy consumption. Similarly, agro-industrial waste contributed significantly to environmental pollution when disposed of in landfills. Waste from date palms is one of the main agro-waste generated in Saudi Arabia. This waste is normally disposed of without treatment or burnt for energy. The date palm ash (DPA) due to its pozzolanic properties could be suitable for use as supplementary cementitious material (SCM) in concrete. However, due to its weak or slower pozzolanic reactivity, the DPA negatively affects the performance of concrete. In this research, the DPA was used as a SCM in concrete. Eggshell powder (ESP) owing to its abundant calcium oxide content was used as an additive to the concrete containing other pozzolanic materials with high silica content. Cement was partially replaced with DPA at dosages between 10% to 40%, and ESP was added at different proportions between 1% to 4% by weight of the binder. The workability of the concrete was decreased with adding blends of DPA and ESP. The mechanical strengths (compressive, flexural, and tensile strengths), modulus of elasticity (MoE), water absorption, and porosity of the concrete were negatively affected by adding DPA. Blending up to 30% DPA with up to 3% ESP as cementitious materials help alleviate the adverse effects of the DPA on the strengths, MoE, and durability performance of the concrete. DPA increases pore volume and porosity by decelerating C-S-H production through its slower pozzolanic reaction at early ages. DPA reduced total embodied CO2 emissions and enhanced the eco-strength efficiency of the concrete. Using DPA and ESP blends in concrete improves performance, minimizes environmental effects, and reduces CO2 emissions during cement production.

Enhanced Catalytic Ozonation of Phenol Degradation by Mn-Loaded γ-Al2O3 Catalyst: A Facile Strategy for Treating Organic Wastewater

Heterogeneous catalysis ozonation technology can achieve efficient treatment of refractory organics in industrial wastewater due to its advantages including fast reaction speed, high ozone utilization rate, low catalyst loss and low cost and has a broad application prospect. The development of efficient and stable heterogeneous ozone catalytic materials is the key to promoting the application of this technology in industrial wastewater treatment. Based on this, an Mn/Al2O3 catalyst was successfully prepared by impregnation method using 3~5 mm γ-Al2O3 pellets as the carrier, and the surface morphology characteristics, elemental state and phase composition of the catalyst were investigated by SEM-EDX, XRD and XPS. The results showed that Mn was successfully loaded onto the surface of a γ-Al2O3 carrier. On this basis, intermittent single factor experiments were conducted to systematically investigate the effects of catalyst dosage, pH, and ozone concentration on the catalytic performance of phenol. It was found that under the optimal conditions of a catalyst dosage of 100 g (filling height of 14.2 cm), pH of 7, and ozone concentration of 4 mg/L (gas volume of 1 L/min), the removal efficiencies of 800 mL 100 mg/L of simulated phenol wastewater reached 100% after 60 min of reaction. The removal efficiencies of the catalyst still reached 95.8% within 60 min even after the fifth cycle reaction, indicating excellent reusability of the catalyst. This work provides a facile strategy for the treatment of refractory organics in industrial wastewater.

Analisis Permintaan Penyaluran Gas PT PGN Dengan Metode Time Series

In the case of gas transmission, the calculation of the gas delivered and the gas currently in the pipe is of course required to be a safe amount in the sense of neither less nor more. A condition where the amount of gas is less than the minimum value of the pipe capacity can cause damage to the pipe because the pressure is below the normal point. Meanwhile, conditions where the gas in the pipe exceeds the maximum capacity value is also very dangerous because it can cause accidents such as pipe leaks and explosions. Therefore, this research was carried out to determine the value of forecasting gas demand by PT PGN to be able to find out the range of gas volumes that must be stored and then distributed by Pertamina Gas to meet PT PGN's demand. Forecasting is a technique of predicting the influence of prevailing conditions and situations on future developments. The method generally used in forecasting is the quantitative method using the time series method.

ALGORITHM FOR DETERMINING THE VOLUME OF NATURAL GAS LOSSES UNDER CONDITIONS OF MEASURING ITS PARAMETERS AT THE GAS PIPELINE OUTLET

Gas pipeline networks are complex distributed systems consisting of hundreds of kilometers of pipelines of various configurations. Equipping all sections of the gas pipelines with gas accounting and gas parameter metering devices that would allow for the quick detection of pipeline damages and the determination of gas loss volumes requires significant funds. As a result, many transportation and distribution pipelines are not equipped with metering devices. Therefore, it is important to develop algorithms that can estimate the volume of gas losses based on information from existing metering units without the reconstruction of gas networks.The paper proposes an improved mathematical model for the stationary flow of natural gas in pipelines which considers the flow velocity changes along the pipeline. This model is supplemented with an equation for calculating the flowrate of gas flowing into the atmosphere through a hole in the damaged above-ground gas pipeline. The authors have developed an equation to determine the discharge coefficient for a pressure range in the pipeline from 0.1 to 1.2 MPa with a methodological error of no more than 1.7%. Based on the obtained mathematical models, an algorithm has been developed to calculate the gas volume lost because of damage for pipeline configurations with gas parameter metering units at the pipeline outlet. The developed algorithm has been validated, and an example of its application for analyzing the distributions of gas pressure and temperature in a pipeline with existing damage is presented. The paper presents the simulation results for gas leakage through pipeline damage and the iterative determination of gas parameters at the damage point, as well as the results of calculating the gas flowrate through the damage.The application of the developed algorithm allows for increased accuracy in determining the volume of gas losses through pipeline damage. Its hardware implementation in the future will reduce the time for damage detection, localization, and elimination.

A cost-effective approach for transitioning to larger wafer production by small Czochralski pullers

As the semiconductor industry continues to evolve, the demand for larger silicon wafers has grown significantly. However, transitioning from traditional 4 and 6-inch wafers to larger sizes poses numerous challenges, especially for smaller semiconductor companies with limited financial resources. This article explores a cost- effective approach to address this transition by modifying a small Czochralski (CZ) puller to grow a larger silicon wafer. The study employed a simulation-based method using 3D transient finite element analysis to evaluate the effects of modifying the CZ puller's B-chamber and thermal shield and applying a cooling jacket. The results show that these modifications can enhance the temperature gradient during crystal growth and improve stability when growing an 8-inch silicon ingot. Practical experiments also highlight the complexities involved in achieving a successful transition to 8-inch wafers, including the need for precise adjustments in gap distances and argon gas volume.

All-Solid-State Battery Safety Investigation in Calorimeter Coupled with Fast X-Ray Radiography

All-solid-state battery (ASSB) are expected to be a solution to increase energy density in Li-ion technology. However, high-energy storage capacities make the safety a crucial issue. The main reactions leading to thermal runaway in conventional LiB are anode/electrolyte at 110 °C, electrolyte decomposition at 150 °C and cathode/electrolyte at 300 °C. Therefore, without liquid electrolyte, it can be expected that ASSB are less likely to have a thermal runaway.To assess safety of such non-fully mature battery technologies, a new methodology is proposed and a closed calorimeter was designed to perform operando experiments in abuse conditions with high-speed synchrotron X-ray radiography and measurement of temperature, pressure and energy. The data and image of thermal runaway of all-solid-state batteries are presented and compared to the result of Li-ion batteries with liquid electrolyte. An 11 % decrease of heat release was measured for cell with solid electrolyte. Gas volume, amount of matter that reacts in the cell and reaction kinetics have also been compared.Such a methodology allows deepening hypotheses on associated material degradation and that can assist in development of new battery technologies, by evaluating battery safety from the start of the design from battery composition to cell shape.

Effect of Operating Temperature and Pressure on the Limiting Current Density of PEM Electrolysis Cell Based on Theoretical Prediction Model and Experiments

Introduction The PEM electrolysis cell (PEMEC) exhibits great potential to produce hydrogen gas. However, the high cost associated with cell components, such as the iridium oxide catalyst and titanium porous transport layer, poses a challenge to the commercialization of PEMEC. So, continued research is needed to improve the cost-effectiveness of PEMEC. Operation at high current densities can minimize the electrode area and reduce capital expenses. However, high current density operation is limited by limiting current density (LCD), which causes a sharp increase in electrolysis voltage. At high current densities, the generation of oxygen gas bubbles creates additional flow restrictions to the water supply and increase overvoltage. Although previous studies have achieved relatively high current densities [1-2], the limit of operating current density and its mechanism still remain unknown.In this study, it reveals the impact of operating temperature and pressure on LCD of a lab-scale PEMEC. The experiments are conducted over a range of temperatures from 80 to 90 ℃ and pressures from 0.1 to 0.3 MPa. In conjunction with experiments, a mathematical model is developed to analyze the mechanism of LCD. The model includes mass and momentum equations for liquid water and oxygen gas through the porous transport layer. And the model also involves electrochemical equations to study overvoltages associated with mass transport. By combining experimental and theoretical analysis, this study provides valuable insights into the factors affecting LCD of PEMECs and facilitates the optimization of high-performance operation. Experimental apparatus The specifications of crucial components such as membrane (PEM), catalyst layer (CL), porous transport layer (PTL) is listed in Table.1 . Nafion NR212 is used as PEM, and the thickness is 51 μm. The catalyst is contained on CL, and its loading amount are 1.5 mg/cm2 IrO2 on anode and 0.5 mg/cm2 Pt on cathode, respectively. The anodic PTL is a Titanium mesh plated by Pt (Nikko Techno, NKT-1803-03), and the carbon paper (SGL 38BA) is used as cathodic GDL. For separators, the anode separator is fabricated from titanium, and the cathode separator is carbon. The anodic and cathodic flow pattern is designed as single-serpentine channels, and the channel depth, channel width, and rib width are 1 mm ×1 mm ×1 mm, respectively. Results and discussions Fig.1 shows the theoretical and experimental I-V curves. In Fig.1, the electrolysis voltage in both experiment and simulation raises abruptly, which is corresponding to LCD. The experimental LCD is 11.6 A/cm2 as indicated by the black circle, and the predicted LCD is 10.1 A/cm2. Although the prediction of LCD is qualitative, simulation could follow the IV characteristics obtained by experiment before LCD.Fig.2 and Fig.3 shows the effect of operating temperature and pressure on LCD. The electrolysis voltage “E” is experimentally determined, while the gas saturation at interface of PTL-CH “Sg” is obtained through simulation. As shown in Fig.2, the lower operation temperature enlarges the LCD, the experimental LCD increases 8% from 90 ℃ to 80 ℃. Theoretically, high operating temperature increases oxygen bubbles and then rises the gas saturation S g at the anode CL. So, the water supply flowing to CL is insufficient, and the electrochemical performance also decrease. Therefore, the overvoltages caused by mass transport becomes larger in higher operating temperature. As shown in Fig.3, higher operating pressure shrinks the volume of oxygen gas and enhance the water supply from CH to CL, leading to a larger LCD. Under 80 ℃, the experimental LCD rises by 17 % from 0.1 MPa to 0.3 MPa.Although the theoretical analysis reproduced the experimental results in a qualitative manner, the theoretical analysis suggests that, when electrolysis current density is quite close to the LCD, water mass transport at anode reaches a limitation, indicating that water saturation drops to zero at anodic catalyst layer. References Lee J K, et al. Cell Reports Physical Science, 2020:100147.A Zinser, et al. International Journal of Hydrogen Energy, 2019, 44(52): 28077-28087. Figure 1