Equilibrium Constant Method Research Articles

Thermodynamic Simulation Model of Copper Side-Blown Smelting Process

In this study, the thermodynamic simulation model and system of the copper side-blown smelting process were established using the chemical equilibrium constant method, based on the process reaction mechanism, multiphase equilibrium principle, and MetCal software platform (MetCal v7.81). Under typical production conditions, the composition of the product and the distribution behavior of impurity elements were simulated. The results indicate that the average relative error between the calculated mass fractions of major elements such as Cu, S, Fe, SiO2, CaO, MgO, and Al2O3 in copper matte and smelting slag, and the actual production values, is 4.25%. Additionally, the average relative error between the calculated distribution ratios of impurity elements such as Pb, Zn, As, Bi, Mo, Au, and Ag in copper matte and smelting slag, and the actual production data, is 6.74%. Therefore, this model and calculation system accurately reflects the actual production situation of the copper side-blown smelting process well and has potential to predict process output accurately while optimizing process parameters, effectively guiding production practice.

Multi-Phase Equilibrium Model of Oxygen-Enriched Lead Oxidation Smelting Process Based on Chemical Equilibrium Constant Method

With the increasingly complicated sources of lead smelting materials, it is becoming more difficult to optimize process parameters during the bottom-blowing lead oxidation smelting process. Building a bottom-blowing lead smelting thermodynamic model has significant importance for the green production of the lead smelting process. In this study, we built a multi-phase equilibrium thermodynamic model and simulation system for the oxygen-enriched bottom-blowing lead oxidation smelting process using the MetCal software platform (MetCal v7.81) according to the chemical equilibrium constant method. The equilibrium products composition and important technical indicators were calculated under factory operating conditions. Compared with the industrial data, the calculation results demonstrated that the average relative error of the calculation value of the mass fraction in the crude lead, lead-rich slag, and dust was 3.76%. The average relative error of important technical indicators, including dust rate, crude lead yield, lead-rich slag temperature, slag iron–silica ratio (RFe/SiO2), and slag calcium–silica ratio (RCaO/SiO2), was 6.39%. As a result, the developed modeling and simulation system was able to reflect the current state of the oxygen-enriched bottom-blowing lead smelting. It also demonstrated the potential to enhance the smelting process and optimize the process parameters. Therefore, it is expected to provide a useful tool for thermodynamic analysis.

Absorption-Enhanced Methanol Steam Reforming for Low-Temperature Hydrogen Production with Carbon Capture

Methanol is a prospective hydrogen storage medium that holds the potential to address the challenges of hydrogen storage and transportation. However, hydrogen production via methanol steam reforming faces several key obstacles, including high reaction temperature (e.g., 250–300 °C) and low methanol conversion (at <200 °C), while the purification procedure of hydrogen is commonly required to obtain high-purity H2. A novel method of H2 absorption-enhanced steam reforming of methanol is proposed to overcome the challenges mentioned above. The method involves the absorption and separation of H2 using an absorbent to facilitate the forward shift of the reaction equilibrium and enhance reaction performance. A thermodynamic analysis using the equilibrium constant method presents that the separation of H2 can improve the methanol conversion rate and the total H2 yield. The feasibility of the method is validated through experiments in a fixed-bed reactor (4 mm diameter, 194 mm length) under the conditions of 200 °C and 1 bar. In the experiments, 1 g of bulk catalyst (CuO/ZnO/Al2O3) and 150 g of bulk hydrogen absorbent (Aluminum-doped lanthanum penta-nickel alloy, LaNi4.3Al0.7 alloy) are sequentially loaded into the reactor. As a proof of concept, a CO2 concentration of 84.10% is obtained in the reaction step of the first cycle, and a gas stream with an H2 concentration of 81.66% is obtained in the corresponding regeneration step. A plug flow reactor model considering the kinetics is developed to analyze the effects of the number of cycles and H2 separation ratio on the enhancement performance. The method indicates a high potential for commercialization given its low reaction temperature, high-purity H2, and membrane-free design.

Consistency Checks for Pressure-Volume-Temperature Experiment of Formation Oil and Gas at High Temperature

The oil and gas phase behavior of high temperature is complex and changeable, which is usually obtained by PVT experiments. The accuracy of the experiment data plays a crucial role in the reserve evaluation and development plan of oil and gas reservoirs. However, the current PVT experiment consistency checks are not suitable for high-temperature reservoir conditions. This paper proposes a systematic check method for the PVT experiment data consistency at high temperature. These checks revise the material balance method, Hoffman method, and equilibrium constant method by using the equilibrium constant calculation method at high temperature. The consistency check of component data and constant volume depletion experiment data is carried out by combining the three improved methods with the component check method, so as to judge the experiment data accurately. In this paper, two high-temperature reservoir fluids—gas condensate sample fluid X and volatile oil sample fluid Y—are selected to carry out consistency checks with component data and constant volume depletion data. This check method is of great significance to study the phase behavior of formation oil and gas at high temperature, especially for volatile oil and gas condensate fluid.

ON THE POSSIBILITY OF IMPLEMENTING CCS PROJECTS IN THE CARBONATE RESERVOIRS OF THE SIBERIAN PLATFORM

Link for citation: Nikitenkov A.N., Novikov D.A., Maksimova A.A., Penigin A.V., Varaksina I.V., Zhukovskaya E.A. On the possibility of implementing CCS projects in the carbonate reservoirs of the Siberian Platform. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 68-78. In Rus. The relevance. Carbon capture utilization and storage technology involving geological storage of carbon dioxide in deep aquifers is widely used in the world as this technology is aimed at decreasing the emission of greenhouse gases into the Earth’s atmosphere and minimizing the influence of these gases on the global climate change. Objective: to carry out preliminary investigation of the features of water – rock – carbon dioxide interactions in application to carbonate collectors, which are widespread in hydrogeological basins over the territory of the Russian Federation and are potentially suitable as carbon dioxide storage facilities. These processes are considered by the example of the ancient Siberian Platform, where industrial production of hydrocarbons is currently increasing, and a series of large-scale projects in the area of petroleum and gas chemistry are under implementation. Methods. Mathematical physical and chemical modeling was applied to solve the problem. The calculations were implemented by the HydroGeo software package, in which the achievement of chemical equilibria for the «water–rock» system is implemented on the basis of the method of equilibrium constants. Results. The obtained results allow us to evaluate the directions of geochemical processes in the collectors under consideration and to provide qualitative estimation of changes in the pore space under the conditions of its saturation with carbon dioxide, with respect to different saturation degrees. It is established that solution acidification is observed as a result of its saturation with СО2, with the transition of chemical elements to the prevailing forms of complex ions bound with hydrocarbonate and chloride ions (Mn, Na, K). At the same time, saturation with carbon dioxide does not have so substantial effect on the forms of Ca and Fe migration. Special attention is attracted to Al, which is transformed almost completely from complex forms into Al3+ in the presence of carbon dioxide. In the studied reference samples, rather intense transformation of collector rocks with redistribution of elements between the primary and secondary mineral phases is observed (both rock dissolution and precipitation up to several hundred g/dm3) with comparatively small absolute changes in open porosity. In a series of the considered objects, the dissolution of calcite and dolomite proceeds due to a decrease in pH. The directions of transformations, as well as the trend of changes in filtration-capacity properties, are determined by the specific mineralogical combination of collector rocks and the brine present in them, as well as by the stage of evolution of the system under consideration (the first part of the considered combinations is initially far from the equilibrium and continues interacting, while the second part is close to the equilibrium and is transformed into non-equilibrium state due to saturation with carbon dioxide).

IDEA: Artificial neural network models for 11-species air properties at thermochemical equilibrium

Accurate prediction of high-temperature air properties is essential in many aerodynamic applications under hypersonic flight conditions. Various curve-fit models using piecewise polynomial fittings have been commonly adopted to approximate equilibrium air properties at high temperatures. Several shortcomings including low accuracy, lack of diversity, and discontinuity at curve-fit boundary still remain, causing numerical troubles in computational procedures. To address the issues, IDEA, an open-source C++ library that enables fast and accurate computations of the equilibrium air properties and their first and second derivatives, is newly developed based on the artificial neural network (ANN).IDEA, which stands for the Infinitely Differentiable Equilibrium Air, predicts thermodynamic and transport properties of 11-species (N2, O2, N, O, NO, NO+, N+, O+, N++, O++, and e−) thermochemical equilibrium air at the temperature range up to 25,000 K and density range from 10−7 to 103 amagats. The training data is constructed from the kinetic molecular theory using the equilibrium constant method with the rigid-rotor, harmonic-oscillator model. As the name suggests, IDEA's models are infinitely differentiable in the application range; thus, they have enhanced convergence in computational fluid dynamics (CFD) when using gradient-based methods. Using a newly developed training process based on the Levenberg–Marquardt algorithm with weighted mean squared error loss, IDEA provides more accurate and diverse property models with much fewer parameters than previous piecewise polynomial fitting models. In addition, the proposed training method offers easy extensions to various property models with different species data. IDEA provides C interfaces that can be used for programs in various computer languages, such as C/C++, Fortran, Python, and MATLAB. IDEA's modeling routines are thread-safe, so they can be safely used for parallel programs without performance loss. The accuracy and enhanced convergence of IDEA is demonstrated via several high-speed flow computations Program summaryProgram title: IDEACPC library link to program files:https://doi.org/10.17632/84rhtfz9n2.1Developers' repository link:https://github.com/HojunYouKr/IDEALicensing provisions: BSD-3-ClauseProgramming language: C++11Nature of problem: Accurate prediction of equilibrium air properties is essential in many aerodynamic applications under hypersonic flight conditions. Direct calculation of air properties by the kinetic molecular theory requires time-consuming iterative methods to solve nonlinear equations of species concentrations. Various piecewise polynomial models have been developed to avoid such iterations. However, the regression error of the polynomial models requires improvement, and the lack of diversity of the polynomial models makes iterative computations inevitable, causing computational inefficiency. Furthermore, these polynomial models are not continuously differentiable, which deteriorates the convergence characteristics of computational fluid dynamics (CFD) solvers.Solution method: ANN is chosen to model the equilibrium properties of air owing to its excellent capability as a universal function approximator and better adaptability to a large dataset than kernel methods. The hyperbolic tangent activation function makes the ANN model infinitely differentiable, which enables to use a superlinear training process and thus improves convergence characteristics. The newly proposed superlinear training process based on the Levenberg–Marquardt algorithm with weighted mean squared error loss provides more accurate and diverse property models with much fewer parameters than the existing polynomial models. As a result, the proposed ANN model is completely free from iterative computations.

Study on electrical conductivity of detonation products of aluminized explosives

Using the thermodynamic equilibrium constant method and JWL-Miller equation of state, based on the calculation of the thermodynamic parameters such as the composition, pressure, and explosion temperature of the detonation products of aluminized explosives in the Magnetocumulative generator, the Saha ionization equation, and gas conductivity calculation model are used to write Matlab code to calculate the electron density and conductivity of the detonation products of the magnetic flux compression generator. The temporal and spatial variation law of electron density and conductivity is revealed. The simulation shows that the thickness of the maximum conductivity layer in the detonation process is about 1 mm and moves at a uniform speed following the CJ surface. The maximum conductivity of HMX/Al (70/30) is 1.88e5 Ω−1·m−1, with an error of 6%, and the maximum conductivity of RA1 (HMX / DNAN / Al) is 2.7e4 Ω−1·m−1

Fuzzy Logic Implementation for Accurate Electric Car Battery SoC Measurement

Changes in temperature can affect the accuracy of the estimated SoC value based on voltage. In this study, fuzzy logic was implemented to correct the SoC estimation error caused by the influence of temperature. The system acquired data through sensors and then processed it using the Arduino microcontroller. Parameters in the form of voltage, temperature, and current were processed by Arduino with a fuzzy logic program which was uploaded into it and produced the output of the estimated SoC value. From the observations, it was found that the estimated SoC value from this method had better accuracy with a smaller error than the SoC estimation based on voltage alone. Using the RMSE method, the errors calculated in this method in the process of charging and discharging without running were 2.26 and 7.74, while the SoC estimation error based on voltage alone reached 4.88 and 12.8. In the discharging process with a running car, the SoC estimation results using fuzzy logic also showed accurate results. There was only 1% of SoC value increasing pattern during the discharging process, which the value trend should continue to decrease and should not be an increase. In addition, compared to the previous method applied to the same research object, namely the chemical equilibrium constant method, this method also showed more accurate results.

Studies on the propagation properties of THz wave in inhomogeneous dusty plasma sheath considering scattering process

The plasma sheath formed during the reentry process is able to block the detection and communication to the hypersonic vehicle. Various of interactions occur during the propagation of EM wave in the plasma sheath. In addition, the dusty particles formed during the ablation of the protective layer make this process more complicated. Dusty plasma sheath is an important factor that affect the detection of hypersonic vehicle. In this work, the propagation properties of THz wave in inhomogeneous dusty plasma sheath are studied. The flow field distribution around the hypersonic vehicle is simulated first. Then the electron density is calculated using equilibrium constant method of the 7-species reacting air model. And the collision frequency is calculated based on the results of the flow field simulation. The absorption and scattering process are studied using scattering matrix method and Mie scatter theory, respectively. The propagation properties are calculated considering the influences of the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The calculation results show that with the increase of THz wave frequency, the transmittance increases firstly and then oscillates. The shape of the transmittance curve is determined by the flight speed, the flight altitude, the radius, the number density and the kind of the ablation particles. The main loss mechanisms in different wave bands has also been discussed and the optimum transition band is given. This work shows that THz wave has good potential applications in hypersonic vehicle detection. It also provides a method to select the optimum detection frequency band.

Computational Account of the First Stages in the Elevator Motion of the Human EAAT3 Glutamate Transporter

The plasma membrane excitatory amino acid transporters (EAATs) belong to mammalian glutamate transporter family that regulates levels of L-Glu in the synaptic cleft. The transport cycle mechanism of the EAATs is believed to be similar to that in its prokaryotic homolog GltPh and involves elevator motion of the transport domain that travels ∼ 2 nm across the membrane from the outward to inward facing state (OFS and IFS). Although EAAT3 has the highest turnover rate among the members of the family (∼ 100 s−1), a thorough molecular dynamical (MD) study of the full transport cycle requires significant computational effort. From extensive MD simulations (∼ 1 millisecond) of WT in fully loaded and apo- states we have extracted structural time-correlations, and along with results obtained with the N-body Information Theory (NbIT) analysis concluded on the main structural elements of the elevator motion. These were verified with in silico mutagenesis of the residues within these structural elements in a set of additional MD simulations. The dynamics of two hairpin motifs in the transport domain (HP1 and HP2) and conformations that favor the motion emerged from these studies, and the role of elongated extracellular loop of EAAT3 that is absent in the GltPh in initiating the elevator motion was outlined. Notably, application of our new equilibrium constant pH method (ECpH) to reveal the pH dependence of EAAT3 function yielded structural insight into the motion of the HP2 and HP1 gates, the role of the Glu374 protonation state, and the interactions influencing the gate opening in HP2 that hinders the substrate transportation.

Research on the Influences of Addition of Biodiesel on the Equilibrium Concentrations and Thermodynamic Properties of Combustion Products for Conventional Diesel Fuel

To deal with the increasingly stringent energy crisis and atmospheric pollution problems, biodiesel is regarded as one of the alternative biofuels with great potential for replacing the conventional diesel fuel, thus it is necessary to investigate the influences of addition of biodiesel to conventional diesel fuel on the combustion products. To this end, Jatropha biodiesel is taken as an example and under the assumption that all the combustion products are at chemical equilibrium, a system of nonlinear equations with the equilibrium concentrations of 10 combustion products as the unknown variables is constructed based on the equilibrium constant method and the numerical solutions are obtained by applying Newton-Raphson iterative method. On this basis the influences of biodiesel blending ratio on the equilibrium concentrations of the combustion products and the thermodynamic properties of burned gases mixture is investigated. The simulation results show that the addition of biodiesel does not cause significant influences on the equilibrium concentrations of combustion product, and as the three major greenhouse and poisonous gases, the relative changes of equilibrium concentration for CO2, NO and CO are less than 3.52% but with unclear trends and the influence is more significant at the “fuel rich” condition; on the other hand, the mass-based combustion products rates of CO2, NO and CO for a unity of blended fuel mass increases with blending ratio. For the thermodynamic properties of burned gases mixture, it is observed that both the constant-pressure and -volume specific heat increase slightly. The model presented here can be integrated into the engine dynamic simulation model conveniently, which lays the foundation for investigating the influence of addition of biodiesel on the engine power, economic and emission performance.

Terahertz wave propagation characteristics in plasma sheath around a hypersonic blunt cone

In this paper, the propagation characteristics of terahertz wave in the plasma sheath is analyzed theoretically, which is simulated and calculated on the basis of the air thermal chemical reactions around a hypersonic blunt cone model. According to the simulation results of the flow field distribution, the electron density of the plasma sheath is fixed through the 7 reacting species equilibrium constant method. The influence of Mach number and flying height on plasma sheath are discussed. And then the interaction model between terahertz wave and plasma sheath is studied by adopting the scattering matrix method. The results show that the plasma parameters are subject to the Mach number and flying height intensely. Moreover, the effects of applied magnetic field on left-hand and right-hand polarized terahertz wave propagation characteristics are considered. The external magnetic field can improve the penetration ability of left-handed polarized terahertz wave. These results demonstrate that terahertz wave has good potential in real-time communication and target detection of near space.

Propagation characteristics of terahertz wave in hypersonic plasma sheath considering high temperature air chemical reactions

In this work, the propagation characteristics of terahertz wave in the hypersonic plasma sheath is demonstrated and analyzed based on the realistic vehicle model and the high temperature air thermal chemical reactions. Based on the simulated flow field distribution around the hypersonic vehicle, the electron densities of the plasma sheath at different Mach numbers are calculated by adopting the equilibrium constant method of the 7-species reacting air model. And then the propagation model of terahertz wave in plasma sheath is established using the scattering matrix method. The calculated and simulated results show that the plasma electron density is strongly influenced by Mach number, and the higher frequency and smaller incident angle of terahertz wave are advantageous for a better transmittance and lower loss. Furthermore, the effects of an external magnetic field on the propagation characteristics of left-hand and right-hand polarized terahertz wave in plasma sheath are studied. The external magnetic field indeed reduces the transmission loss of the left-handed wave. This work promises that terahertz waves have good potential applications in the detection and the communication for the hypersonic vehicles in plasma sheath.

Calculation of thermal physical parameters of dissociated air by the dissociation degree method

The high temperature gas occurs behind shock or near the wall surface of vehicle in the hypersonic flight. As the temperature exceeds 2 000 K, 4 000 K, respectively, O 2 and N 2 molecules are successively dissociated. Because of variable components at different temperatures and pressures, the dissociated air is no longer a perfect gas. In this paper, a new method is developed to calculate accurate thermal physical parameters with the dissociation degree providing the thermochemical equilibrium procedure. Based on the dissociation degree, it is concluded that few numbers of equations and the solutions are easily obtained. In addition, a set of formulas relating the parameter to the dissociation degree are set up. The thermodynamic properties of dissociated air containing four-species, O 2 molecule and N 2 molecule, O atom and N atom, are studied with the new method, and the results are consistent with those with the traditional equilibrium constant method. It is shown that this method is reliable for solving thermal physical parameters easily and directly.

Thermodynamic Analysis on Reaction Characteristics of the Coupling Steam, CO2 and O2 Reforming of Methane

This study presents an analysis of coupling steam, CO2 and O2 reforming of CH4 using the thermodynamic equilibrium constant method. Effects of molar ratio of O2/CH4, H2O/CH4 and CO2/CH4 on reforming characteristics in both carbon deposition and carbon-free systems are analyzed. The results indicate that CH4 conversion rate, H2, and CO yield increase with increasing O2/CH4 molar ratio in two systems. In addition, the carbon elimination is achieved when O2/CH4 ratio increases to 0.31, and changing the amount of O2 can be an effective way to alter n(H2)/n(CO) ratio in the carbon deposition systems. CH4 conversion rate increases with increasing H2O/CH4 ratio in the carbon-free system, while it declines in the carbon deposition system. H2O plays a role of altering n(H2)/n(CO) ratio, and its effects on two systems are opposite. The deposited carbon is totally eliminated when H2O/CH4 ratio increases to 0.645. The increase of CO2/CH4 molar ratio leads to a rapid increase of CO2 conversion when CO2/CH4 ratio is less than 0.5. A slightly change of CO2/CH4 ratio can result in a huge difference on n(H2)/n(CO) ratio in both systems, and carbon elimination is achieved at CO2/CH4 = 0.99. The analyzed results have theoretical significance to efficiently catalyze methane coupling.

Thermodynamic Modeling and Optimization of the Copper Flash Converting Process Using the Equilibrium Constant Method

Based on the principle of multiphase equilibrium, a mathematical model of the copper flash converting process was established by the equilibrium constant method, and a computational system was developed with the use of MetCal software platform. The mathematical model was validated by comparing simulated outputs, industrial data, and published data. To obtain high-quality blister copper, a low copper content in slag, and increased impurity removal rate, the model was then applied to investigate the effects of the operational parameters [oxygen/feed ratio (ROF), flux rate (RF), and converting temperature (T)] on the product weights, compositions, and the distribution behaviors of impurity elements. The optimized results showed that ROF, RF, and T should be controlled at approximately 156 Nm3/t, within 3.0 pct, and at approximately 1523 K (1250 °C), respectively.

Investigation on the solution of nitric oxide emission model for diesel engine using optimization algorithms

Research on reducing the NO emission from internal combustion engine is a challenging work. NO emission prediction model plays a significant role in simulation-based research. According to extended Zeldovich, the determination of equilibrium concentration of combustion products is vital in the prediction of NO formation. Besides the well known STANJAN and Newton-Raphson iteration, Trust-region dogleg, PSO (Particle Swarm Optimization), and GA (Genetic Algorithm) are added to investigate the performance of those methods on the determination of combustion products. Twelve species are considered in the combustion products. STANJAN uses minimizing Gibbs energy to derive the needed nonlinear equations while the others use Equilibrium Constant Method. In terms of the results, it is found that Trust-region dogleg method shows the best performance which achieves the desired accuracy within 0.1 s and the calculated results are comparable to STANJAN. In addition, perturbed PSO also reveals excellent global convergence capability. On the contrary, unmodified Newton-Raphson is unsuitable for this problem and Newton-Raphson downhill shows satisfactory performance neither. According to the results of parameter study, the equilibrium concentrations of combustion products are greatly influenced by equivalence fuel-air ratio and temperature but little affected by pressure. The NO formation process shows good agreement with AVL BOOST. Compared to measured value, the best-predicted emission value reaches −5.45% but the worst drops to −17.72%.

Synthesis of diethyl carbonate from ethanol through different routes: A thermodynamic and comparative analysis

In this study, thermodynamic analysis of various possible synthesis routes of diethyl carbonates (DEC), a benign organic carbonate, was carried out and a comparative analysis was performed. Chemical equilibrium constants at standard conditions were calculated using Gibbs free energy of the system. The Benson group contribution method was used to estimate standard heat of formation and standard entropy change of some raw materials/components like dimethyl carbonate. Variation of heat capacity (Cp) with temperature was estimated for different components from the Rozicka‐Domalski model. Variation of chemical equilibrium constants with temperature and pressure was studied for various routes. Synthesis of DEC from ethylene carbonate (EC) was also found to be better considering equilibrium constants at room temperature. The CO2 route was found to be the most unfavourable route for DEC synthesis due to stability of CO2 molecules. Moreover, DEC synthesis through the urea route was found to be best at high temperatures since the equilibrium constants were found to increase exponentially. Experiments were conducted for DEC synthesis using the EC route at two temperatures. Activity coefficients were calculated using the UNIFAC model. Experimentally and theoretically determined chemical equilibrium constant values were found to be similar. PRO/II was also used to minimize Gibbs free energy of the system and estimate the equilibrium constants and the results were comparable with those obtained by the equilibrium constant method and the trend was found to be the same for both the methods.

Characteristics of combined carbon dioxide reforming with partial oxidation of methane to produce hydrogen in the membrane reactor

Thermodynamic equilibrium constant method and mathematical model are used to analyze the investigating effects of temperature, α[oxygen-methane molar ratio] and β [carbon dioxide-methane molar ratio] on characteristics of oxidative CO2 reforming of methane reaction over Ni/Al2O3 catalysts to produce hydrogen in the membrane reactor. While keeping temperature at 1100 K, the membrane reactor is no longer useful to separate hydrogen when α > 0.6 for hydrogen in reaction side is no longer to permeate side. When increasing β, the methane conversion goes up firstly until the β is 1.3, which is higher than the inflection point at 1.1 in the model prediction. The hydrogen yield peaks at β = 0.5 in permeate side. Increasing the temperature or reducing the β will cause the molar ratio of H2/CO increase. However, changing α has no significant effect on adjusting the molar ratio of H2/CO. By establishing equilibrium reaction model, the system performance can be accurately predicted. Copyright © 2016 John Wiley & Sons, Ltd.

Preparation of ZnGa2S4 by reacting GaI3 and ZnI2 with sulfur

We have carried out thermodynamic modeling of the GaI3–S and ZnI2–S systems by the method of equilibrium constants and calculated the chemical compositions of the condensed and vapor phases in the temperature range 200–500°C. Our experimental data demonstrate the feasibility of preparing zinc thiogallate by reacting gallium(III) iodide and zinc(II) iodide with sulfur. Synthesis was carried out at a temperature of 450°C over a period 2 h, followed by calcination of the product at 650°C in order to remove the residual iodine. The practical ZnGa2S4 yield was 92–94%.