Gas Formation Processes Research Articles

Potential of Renewable Energy Biogas from Plant (Hyacinth)

<p class="Abstract">Energy is one of the basic human needs, both in the form of electricity and energy in the form of heat / gas. The increase in Indonesia's population has increased by 1.3% every year, this is comparable to the increase in energy needs. Current conditions illustrate that the fulfillment of energy needs is sourced more from fossil materials that cannot be renewed, therefore a solution is needed to overcome these problems by finding and finding potential alternative energy sources that can meet human needs. One of the energy that can be utilized is biogas. Biogas is a process of fermentation of organic matter that produces methane gas. Organic materials available in nature are abundant, one of which is organic matter derived from water hyacinth. For this reason, a research study is needed by identifying the potential of biogas energy from water hyacinth. This research is an experimental research, the data collection technique is done by quantitative methods. The tools needed are a manometer, thermometer and biogas reactor. This research was conducted by measuring the temperature and pressure produced by biogas made from organic water hyacinth. The results obtained showed that the biogas produced from water hyacinth produced a gas odor that was relatively not too stinging and the gas formation process was faster. Gas pressure measurements are carried out using a monometer by calculating the difference in the height of water pressure in the U pipe. Measurements of pressure changes are carried out for 20 days by conditioning external factors such as temperature and humidity. The study was conducted to examine the effect of adding water hyacinth to biogas organic matter. The results obtained that t count> t table is the value of t arithmetic (8.183)> t table (2.093) and the significance level of 0.000 <0.05. This means that there are differences in biogas production between before adding water hyacinth and after adding water hyacinth.</p>

Numerical and Experimental Investigation on Tube Hot Gas Forming Process for UHSS

Ultra-high strength steels (UHSS) have been regarded as one of the most attractive alternatives for lightweight parts in automotive industry. In this study, the tube hot gas forming process is introduced to implement high temperatures forming for UHSS tubular components. In the proposed process, the tube blank is first heated up to 900 °C for several minutes to achieve homogeneous austenitization and then quickly transferred to a press for forming. Nitrogen gas replaces? water in traditional hydro-forming process as media to apply internal pressure in a heated tube. To enhance the energy absorption capability of the components, a one-step quenching and partitioning (Q&P) process is conducted by the die cooling during deforming simultaneously to increase the elongation and ductility of the material. Moreover, a numerical investigation on a tube component fabricated from 22MnB5 steel is performed. The temperature distribution and microstructure evolutions are studied, which demonstrates the forming quantity advantages of tube gas forming process.

Gas forming of shallow rounded rectangular pan using aluminum alloy sheets

Hydroforming involves the use of a pressurized fluid to form complex and/or intricate component shapes and includes three currently available manufacturing techniques—superplastic forming (SPF), quick plastic forming (QPF), and gas forming, which however, is seldom used. This gas-forming technique involving the use of gas pressure along with four different die-entrance geometries to form a shallow rounded rectangular pan—having a width-to-depth ratio of approximately 10—from aluminum alloy sheets has been explored and reported. The relevant experimental process is appropriately described and analyzed along with associated failure patterns observed in specimens. Adoption of a two-stage forming process involving preform production is proposed to address the problem associated with die-entrance contours. Lastly, the procedure concerning selection of an optimum Al alloy conducive for use in the gas-forming process has been explained. The gas-forming technique discussed herein is well-suited for use in mass production of metallic cases for smartphones. In addition to achieving the desired contour, other crucial criteria, such as production rate, product surface quality, and dimensional precision, need to be addressed through further research.

Research of the effect of hydrobionts and lactic acid adjuncts on the gassing power of grain mixture for baked goods

Baked goods are regularly massively consumed products. By regulating their chemical composition, we can significantly influence the diet and human health. In solving this problem, the promising is the production of baked goods from whole grains, which allows maximum preservation of inherent nutritional potential of grains and the use of marine dietary adjuncts, marine and fresh-water algae, fish flour, and hydrolysates in the formulation. One of the critical indicators characterizing the intensity of alcohol fermentation during the dough preparation is gassing, which greatly affects the volume and doughiness of semifinished products from the dough and the porosity of bread structure. Therefore, the objective of this article was to study the effect of sources of lactic acid and adjuncts plant and animal hydrobionts on the gassing process in grain mixture for baked goods. At the first stage of the study, a change in the amount of formed gas and the rate of gas formation in the dough in the production of grain bread were determined, depending on the sources of lactic acid. At the second stage, the effect of hydrobiont adjuncts on the process of gas formation was determined. According to the data obtained, the lactic acid starter concentrate and cheese whey as a source of lactic acid in the fermentation of the grain mixture have the most beneficial effect on the process of gas formation. A gas formation rate of the samples with these adjuncts is 11.73 cm3/min and 10.56 cm3/min, respectively. Maximums of gas formation are in the range of 15-25 minutes and 50-70 minutes. All hydrobionts adjuncts used in the studies contribute to the intensification of the fermentation test and the separation of test blanks due to the enrichment of the dough with biologically active compounds, which leads to the activation of the processes of yeast cells vital activity. Addition of hydrolysates from mollusks has the greatest effect on the rate of gas formation, increasing it by 22.66-26.01% compared to control. The addition of cystoseira increases the overall rate of gas formation by 19.35-22.98%, and the addition of duckweed - by 12.68-16.56%. The prospect of further researches is the study of the influence of hydrobionts adjuncts on physical and chemical changes in the yeast dough and flour technologies development with their use

In Situ Characterization of Gassing Processes in Lithium-Ion Batteries By Dems-Deirs

Gas evolution has a profound effect on the functioning of state of the art lithium-ion batteries. On the one hand, it is the natural concomitant of SEI formation; on the other hand, because of the demand for high terminal voltages, it is the consequence of electrolyte or electrode material oxidation. This happens on the expense of the efficiency. Furthermore, the presence of gases in the cell raises safety problems. In general it is important to understand gas formation processes. First, to be able to develop novel electrolyte mixtures or tailor electrolyte additives that form a stable SEI. Second, to optimize the surface and/or structure of cathode materials to influence both their bulk oxidative properties upon delithiation and electrocatalytic activities. Differential electrochemical mass spectrometry (DEMS) is one of the most appropriate tools to qualitatively elucidate gas evolution reactions in electrochemical systems. Herein, we report on the in situ gas analysis by means of differential electrochemical mass spectrometry and infrared spectroscopy (DEMS-DEIRS) of various battery systems. We analyze the SEI formation on different anode materials and the influence of various electrolyte additives. The impact of temperature and constant voltage/OCV periods on the first charge cycle (so-called formation process) is investigated. Their effect on both the gassing and electrolyte salt decomposition is described. The stability problem of the most common electrolytes at high voltages is discussed through the example of either NMC (LiNixMnyCozO2) type materials or with high voltage spinels (LiNi0.5Mn1.5O4). The electrocatalytic activity of the individual active material particles seems to play a decisive role in the oxidative decomposition processes. Through the application of modified cathode surfaces a relation between surface activity and the amount of produced gases is revealed. Beyond the decomposition of the electrolyte, oxygen evolution is the crucial factor at high cathode potentials. This effect is particularly apparent for overlithiated and high Ni content materials. Monitoring gassing over 20 cycles uncovers interesting changes being only recognizable in “long term” tests. We demonstrate the importance of potentiodynamic cycling in addition to the traditional galvanostatic test with DEMS-DEIRS in the exploration of reaction mechanisms. Pressure measurements complete the analysis in terms of validation of gas amounts.

In Situ Characterization of Gassing Processes in Lithium-Ion Batteries By Dems-Deirs

Gas evolution strongly affects the functioning of state of the art lithium ion batteries. On the one hand, it is the natural concomitant of SEI formation; on the other hand, because of the demand for high terminal voltages, it is the consequence of electrolyte or electrode material oxidation. This happens on the expense of the efficiency. Furthermore, the presence of gases in the cell raises safety problems. Both the above mentioned gas formation processes are important to understand. First, to be able to develop novel electrolyte mixtures or tailor electrolyte additives that form a stable SEI. Second, to optimize the surface and/or structure of the cathode materials to influence their bulk oxidative properties upon delithiation and electrocatalytic activities. Herein, we present results on the in situ gas analysis by means of differential electrochemical mass spectrometry and infrared spectroscopy (DEMS-DEIRS) of various battery systems. We analyse the SEI formation on different anode materials and the influence of various electrolyte additives. The impact of temperature and constant voltage/OCV periods on the first charge cycle (so-called formation process) is investigated. Their effect on both the gassing and electrolyte salt decomposition is described. The stability problem of the most common electrolytes at high voltages is discussed. These are achieved either with NMC (LiNixMnyCozO2) type materials or with high voltage spinels (LiNi0.5Mn1.5O4). Beyond the decomposition of the electrolyte, oxygen evolution is the crucial factor at high cathode potentials. This effect is particularly apparent for overlithiated and high Ni content materials that will be presented as well. Monitoring gassing over 20 cycles reveals interesting changes in its characteristic being only recognizable in long term tests. We demonstrate the importance of potentiodynamic cycling tests beneath the traditional galvanostatic ones with DEMS-DEIRS in the exploration of reaction mechanisms. Pressure measurements complete the analysis in terms of validation of gas amounts and supplement them with three-electrode long term investigations.

Hot bend assisted gas forming of AA5083 sheet for making V-shaped trough containing deep uneven concavities

Employing low pressurized gas for shaping superplastic metal sheets into complex contours has long been adopted in the aero/auto industries and it is commonly recognized as superplastic forming (SPF). The most undesired feature of SPF would be an uneven thickness distribution in the final formed part. However, there are techniques that lessen this disadvantage. Low pressurized gas was used to make a V-shaped trough containing deep uneven concavities using superplastic AA5083. The auxiliary yet influential procedure of mechanically hot bending the flat sheet into a V-shape precedes the gas-forming process. In this first quick hot-bending operation, buckling will occur if the depth of bending exceeds a certain level. The degree of buckling and associated contours will affect the thickness distribution as well as the wrinkling location in the gas-formed product. A better thickness distribution is obtainable at the cost of wrinkle formation. Wrinkling can be purposely arranged to achieve better uniform thickness distribution, but it needs to be located outside the trim line of the gas-formed semi-product. Therefore, it is critical to manipulate the hot bending procedure to yield a suitable pre-form allowing a successful sequential gas-forming process.

Novel Experimental Set-Up to Test Tubes Formability at Elevated Temperatures

In the last ten years, the automotive sector presents large interest for light alloys tubes for structural and body car parts to reduce CO2 emissions. Tubes hydroforming is one of the most popular processes to obtain complex parts by using liquids as active part of the dies (i.e. water-or oil-based emulsions) with reduced costs of equipment and machines. However, when elevated temperatures should be used to increase the material formability, hydroforming processes are strongly limited due to the boiling point of liquids. The use of gas at elevated temperature in the so-called Hot Metal Gas Forming process (HMGF) has shown promising capabilities thanks to the increased formability and the possibility to form parts with lower pressures. The paper focuses on a novel experimental set-up to evaluate the tubes formability at high temperatures. Tubes are heated by electric current and air in pressure is used to form the material. Aluminium alloy AA6060 tubes specimens were used to test the experimental equipment and evaluate temperature and pressure ranges able to shape the material.

Weste products of steel galvanizing processes for obtaining technology of colored glazes

The subject of this research is glass-forming compounds pegmatite-slag of thermal pover plants-waste products of galvanizing processes based on frits. The subject of this research is colored low-melt glazes. The objective of the work is elaboration of compounds and technology obtaining colored glazes using waste products of steel galvanizing processes. Up-to-date methods of investigation (X-ray phase analysis, differential thermal analysis, flame photometry and optical electroscopy) have been used in this work. Peculiarities of the formation of slimes of steel parts galvanizing and their properties have been investigated. The processes of gas formation in the process of thermal treatment of slimes have been studied in the range of temperatures 293…1773 K. Regularities of crystallization of coloring crystal phases α-Fe 2 o 3 , ZnO •Fe 2 o 3 and Feo•Fe 2 o 3 that ensure obtaining colored glazes have been established. Technology of obtaining low-melt glazes of brown and cherry-brown colors based on low-melt frit without adding additional ceramic pigments with firing temperature 1343…1373 K has been elaborated. It was established, that with the increase of slime content from 10 to 30 weight % in the composition of glazes the color of coating changes from brown to cherry-brown and the purity of color increases from 31 % to 47 %. The obtained compositions of such glazes were successfully tested under the manufacturing conditions and confirmed the possibility of producing decorative oven ceramic tiles with improved decorative and maintenance properties.

Modeling Gas Formation and Mineral Precipitation in a Granular Iron Column

In granular iron permeable reactive barriers (PRBs), hydrogen gas formation, entrapment and release of gas bubbles, and secondary mineral precipitation have been known to affect the permeability and reactivity. The multicomponent reactive transport model MIN3P was enhanced to couple gas formation and release, secondary mineral precipitation, and the effects of these processes on hydraulic properties and iron reactivity. The enhanced model was applied to a granular iron column, which was studied for the treatment of trichloroethene (TCE) in the presence of dissolved CaCO(3). The simulation reasonably reproduced trends in gas formation, secondary mineral precipitation, permeability changes, and reactivity changes observed over time. The simulation showed that the accumulation of secondary minerals reduced the reactivity of the granular iron over time, which in turn decreased the rate of mineral accumulation, and also resulted in a gradual decrease in gas formation over time. This study provides a quantitative assessment of the evolving nature of geochemistry and permeability, resulting from coupled processes of gas formation and mineral precipitation, which leads to a better understanding of the processes controlling the granular iron reactivity, and represents an improved method for incorporating these factors into the design of granular iron PRBs.

Gas Forming a V-Shape Aluminum Sheet into a Trough of Saddle-Contour

A sheet metal trough of aluminum alloys is manufactured by gas-forming process at 500 °C. The product with slope walls is of ~1.2 m long and ~260 mm opening width, comprising two conical sinks at two ends. The depth of one sink apex is ~350 mm, which results in the depth/width ratio reaching 1.4. To form such a complex shape with high aspect ratio, a pre-form of V-shape groove is prepared prior to the gas-forming work. When this double concave trough is turned upside down, the convex contour resembles the back of a twin hump camel. The formability of this configuration depends on the gas pressurization rate profile, the working temperature, material’s micro-structure, as well as pre-form design. The latter point is demonstrated by comparing two aluminum alloys, AA5182 and SP5083, with nearly same compositions but very different grain sizes.

Prediction of Rupture in Gas Forming Process Using Continuum Damage Mechanic

The Continuum Damage Mechanics is a branch of applied mechanics that used to predict the initiation of cracks in metal forming process. In this article, damage definition and ductile damage model are explained, and also ductile damage model is applied to predict initiation of fracture in gas metal forming process with ABAQUS/EXPLICIT simulation. In this method instead of punch, the force is applied by air pressure. In this study, first the ductile damage criterion and its relations are taken into account and, subsequently, the process of gas-aid formation process is put into consideration and ductile damage model for prediction of rupture area is simulated using ABAQUS simulation software. Eventually, the process of formation via gas on the aluminum with total thickness of 0.24 [mm] was experimentally investigated and the results acquired from experiment were compared with relating simulations. The effect of various parameters such as radius of edge matrix, gas pressure and blank temperature has been evaluated. Simulation was compared with experimental results and good agreement was observed.

A Study on Constitution Equation of Industrial Ti-6Al-4V for Gas Forming Process

An elevated temperature deformation test of industrial coarse-grained Ti-6Al-4V(TC4), which is for gas forming process, was conducted under the temperature of 880 ~ 980°C and the strain rate of 5×10-4mm/s, 1×10-3 mm /s, 5×10-3 mm /s, 1×10-2 mm /s. Based on the stress-strain curve of that material, the Johnson-Cook model, Exponential model, Series model, Parallel model and the Kumar model were established by using the regression analysis on stable deformation stage and whole strain stage (strain hardening stage plus stable deformation stage) respectively. The appropriate application circumstances of those models are analyzed. By using statistic analysis and aiming at minimizing the error rate between actual value and regression value, Kumar model is selected as the constitutive model of that material for gas forming test. Based on Kumar model, the industrial coarse-grained TC4 gas forming test was simulated by nonlinear finite element software Msc.Marc. The simulation results agree well with the actual parts. The Kumar model was appropriate and accurate.

The atomic-to-molecular transition and its relation to the scaling properties of galaxy discs in the local Universe

We extend existing semi-analytic models of galaxy formation to track atomic and molecular gas in disk galaxies. Simple recipes for processes such as cooling, star formation, supernova feedback, and chemical enrichment of the stars and gas are grafted on to dark matter halo merger trees derived from the Millennium Simulation. Each galactic disk is represented by a series of concentric rings. We assume that surface density profile of infalling gas in a dark matter halo is exponential, with scale radius r_d that is proportional to the virial radius of the halo times its spin parameter $\lambda$. As the dark matter haloes grow through mergers and accretion, disk galaxies assemble from the inside out. We include two simple prescriptions for molecular gas formation processes in our models: one is based on the analytic calculations by Krumholz, McKee & Tumlinson (2008), and the other is a prescription where the H_2 fraction is determined by the kinematic pressure of the ISM. Motivated by the observational results of Leroy et al. (2008), we adopt a star formation law in which $\Sigma_{SFR}\propto\Sigma_{H_2}$ in the regime where the molecular gas dominates the total gas surface density, and $\Sigma_{SFR}\propto \Sigma_{gas}^2$ where atomic hydrogen dominates. We then fit these models to the radial surface density profiles of stars, HI and H_2 drawn from recent high resolution surveys of stars and gas in nearby galaxies. We explore how the ratios of atomic gas, molecular gas and stellar mass vary as a function of global galaxy scale parameters, including stellar mass, stellar surface density, and gas surface density. We elucidate how the trends can be understood in terms of three variables that determine the partition of baryons in disks: the mass of the dark matter halo, the spin parameter of the halo, and the amount of gas recently accreted from the external environment.

Modeling Decomposition of MSW in a Consolidating Anaerobic Reactor

A numerical model is presented based on conceptual considerations of chemical and biological reaction processes in landfills. The model enables the details of mixed-culture population dynamics and locally based multiple reaction schemes to be described as functions of the chemical and physical environmental conditions. In its current stage of development, the model is primarily used as a research tool to analyze the influence and value of various model parameters on biodegradation and landfill gas formation processes. In order to test the accuracy of the model, simulation results have been compared with experimental data obtained from a 340-day experiment on the degradation of waste within a “consolidating anaerobic reactor (CAR).” A good match with simulated results was obtained to the measurement of methane and carbon dioxide formation, as well as to the measured concentrations of sulphate and ammonium ions in the liquid phase. In particular, the experimentally observed influence of sulphate on the meth...

The solar transformity of oil and petroleum natural gas

This paper presents an emergy evaluation of the biogeochemical process of petroleum formation. Unlike the previous calculation, in which the transformity of crude oil was back calculated from the relative efficiency of electricity production and factors relating coal to transportation fuels and transportation fuels to crude oil, we analyzed the geochemical process of petroleum formation (naftogenesis) to determine the transformities of oil and natural gas. We assumed that the process of oil and gas production is a steady state process in which all the emergy required is captured in the initial input. For such a system, we can use the mass concentration of the initial input to determine the specific emergy and transformity of the products. We used the maximum photosynthetic yield in Joules of phytoplankton organic matter per Joule of sunlight as the starting point. From this initial assumption, we traced the energy transformations in the oil and gas formation process through photosynthesis, death and decay of the phytoplankton, and diagenesis to kerogen production and from kerogen through catagenesis to petroleum formation. Our results show that both methods converge to similar values for oil (∼54,200 solar emJoules per Joule (sej/J)) and petroleum natural gas (43,500 sej/J) increasing our confidence in the results of past emergy analyses and providing a firm basis for the calculation of transformities for oil and gas derivatives.

Evaluation of VRLA battery under overcharging: model for battery testing

Theoretical cell model is applied for evaluation of valve-regulated lead–acid batteries under discharge, recharge and overcharge conditions. The previously presented models are improved by introducing a new formula for electrode morphology, applying charging factor to state-of-charge, electrode porosity and acid concentration as well as considering the recombination of oxygen as mass-transport limited evolution process. Also, a new model is proposed for the ohmic resistance of a battery. The modified cell model is calibrated using experimental data. Results show that high prediction accuracy can be obtained for the full discharge–recharge cycle including deep discharge and overcharge. The modified cell model is applied for evaluation of the gas formation processes using externally measured current, voltage and temperature of a battery.

Gas-Generating Porous Electrodes: Calculating Characteristics in the Low-Polarizability Portion

It is shown in the paper how specific features of the structure of the porous space in gas-generating porous electrodes (GGPE) create conditions for the emergence of a low-polarizability portion (LPP) in a polarization curve (PC). A set of equations is derived, which allows one to perform calculation of PC in the initial part of LPP. In the region of small overvoltages and in the initial part of a low-polarizability portion, calculations of basic characteristics of GGPE are performed. The calculations are carried out with the values of constants that are close to those that take place for the process of chlorine generation in dimensionally stable anodes. The shape of PC is established, together with the distribution of the oversaturation of electrolyte solution with gas over the GGPE thickness, the specific liquid surface area at which the electrochemical process of gas generation occurs, the amount of gas in the pores of the porous electrode, the overvoltage dependence of the oversaturation of electrolyte solution with gas at the front surface of GGPE, and the magnitude of the effective penetration depth of the process of gas formation into the porous electrode.

Some aspects on the optimum repository plug design with respect to the escape of gas

BfS is in the progress of developing a closure concept for the repository for low and intermediate level radioactive waste in Morsleben (ERAM). In the course of this work, the optimal design of the plug is currently being evaluated with respect to gas escape and the exchange of potentially contaminated brine through the plug. For the sealing to behave well in the long term, it is important that the gas formation processes do not disrupt the plug or enhance the radionuclide release, e.g. by means of excessive pressure build-up. The object has been to study different scenarios for gas and brine transport for two alternative plug concepts, by using the multi-phase flow model TOUGH. Rock convergence due to creep has been included in the modelling. The results of the calculations indicate that the closure concepts restrict he exchange of brine and allow escape of gas; an excavation-damaged zone around tunnels is a potential pathway for gas and brine, and the effect of the rock convergence is small. The results also indicate that a very dense plug results in excessive pressurisation of the repository, whereas a permeable plug results in an increased exchange of brine.

96/01430 Mathematical modeling of gas formation process in coal channel-reactor

96/01430 Mathematical modeling of gas formation process in coal channel-reactor