The dynamical and thermodynamical analysis of the oceanic response to storm

In this paper, the discussion is made on the problem of the oceanic response caused by air-sea interaction under storm. First, the perturbation differential equations for the problem are given, and the interaction functions are supposed to be the solving conditions. Next, the nonlinear diffusion equations of the problem are solved by using the method of the given variable transforms and the specific variable power series. Finally, the response disturbances to the circular intense storm is calculated so as to discribe quantitatively the evolution processes of the oceanic response.

Thermodynamic and Equilibrium Composition Analysis of Using Iron Oxide as an Oxygen Carrier in Nonflame Combustion Technology

Nonflame combustion technology （NFCT） is a harmonious energy utilization technology. There are not environmental-unfriendly gases such as NOx, CO2 discharged in the whole combustion process. Combustion processes realizes zero emission through this technology. Fe2O3 is involved as oxygen carrier, is examined thermodynamically, and the thermodynamic data of the redox reactions are calculated. Using the criteria of minimizing the Gibbs free energy, the equilibrium composition was investigated. The equilibrium analysis shows that producing complete oxidized resultants must have high molar ratio of Fe2O3/CH4. If quantity of Fe2O3 is not sufficient, more partial oxidized products such as CO, H2, even C will be produced.

Thermodynamic analysis of combined reforming process using Gibbs energy minimization method: In view of solid carbon formation

Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure （1-25 atm）, temperature （600-1300 K）, carbon dioxide to methane ratio （0-2） and oxygen to methane ratio （0-1）. The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition.

Thermodynamic analysis and combined cycle research on recoverable pressure energy in natural gas pipeline

Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produced from capturing the pressure energy has been calculated. Based on the comprehensive thermodynamic analysis, two systems have been proposed to capture pressure energy of natural gas to generate electricity. In this study, the expression of exergy is given which can be used in evaluating purposes. A problem with this multidisciplinary study is the complicated boundary condition. In conclusion, a technical prospect on recoverable natural gas pressure energy has been presented based on total energy system theory.

Thermodynamic analysis of the carbothermic reduction of a high-phosphorus oolitic iron ore by FactSage

A thermodynamic analysis of the carbothermic reduction of high-phosphorus oolitic iron ore（HPOIO） was conducted by the Fact Sage thermochemical software. The effects of temperature, C/O ratio, additive types, and dosages both on the reduction of fluorapatite and the formation of liquid slag were studied. The results show that the minimum thermodynamic reduction temperature of fluorapatite by carbon decreases to about 850°C, which is mainly ascribed to the presence of SiO_2, Al_2O_3, and Fe. The reduction rate of fluorapatite increases and the amount of liquid slag decreases with the rise of C/O ratio. The reduction of fluorapatite is hindered by the addition of CaO and Na_2CO_3, thereby allowing the selective reduction of iron oxides upon controlled C/O ratio. The thermodynamic results obtain in the present work are in good agreement with the experimental results available in the literatures.

Oxidative reforming of methane for hydrogen and synthesis gas production:Thermodynamic equilibrium analysis

A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization （at constant pressure and temperature） and entropy maximization （at constant pressure and enthalpy） methods,to determine the equilibrium compositions and equilibrium temperatures,respectively.Both cases were treated as optimization problems （non-linear programming formulation）.The GAMS 23.1 software and the CONOPT2 solver were used in the resolution of the proposed problems.The hydrogen and syngas production were favored at high temperatures and low pressures,and thus the oxygen to methane molar ratio （O 2 /CH 4） was the dominant factor to control the composition of the product formed.For O 2 /CH 4 molar ratios higher than 0.5,the oxidative reforming of methane presented autothermal behavior in the case of either utilizing O 2 or air as oxidant agent,but oxidation reaction with air possessed the advantage of avoiding peak temperatures in the system,due to change in the heat capacity of the system caused by the addition of nitrogen.The calculated results were compared with previously published experimental and simulated data with a good agreement between them.

The thermodynamics analysis and experimental validation for complicated systems in CO_2 hydrogenation process

Catalytic conversion of COinto chemicals and fuels is an alternative to alleviate climate change and ocean acidification.The catalytic reduction of COby Hcan lead to the formation of various products:carbon monoxide,carboxylic acids,aldehydes,alcohols and hydrocarbons.In this paper,a comprehensive thermodynamics analysis of COhydrogenation is conducted using the Gibbs free energy minimization method.The results show that COreduction to CO needs a high temperature and H/COratio to achieve a high COconversion.However,synthesis of methanol from COneeds a relatively high pressure and low temperature to minimize the reverse water-gas shift reaction.Direct COhydrogenation to formic acid or formaldehyde is thermodynamically limited.On the contrary,production of CHfrom COhydrogenation is the thermodynamically easiest reaction with nearly 100%CH4 yield at moderate conditions.In addition,complex reactions with more than one product are also calculated in this work.Among the considered carboxylic acids（HCOOH,CHCOOH and CHCOOH）,propionic acid dominates in the product stream（selectivity above 90%）.The same trend can also be found in the hydrogenation of COto aldehydes and alcohols with the major product of propionaldehyde and butanol,respectively.In the process of COhydrogenation to alkenes,low temperature,high pressure,and high Hpartial pressure favor the COconversion.CHis the most thermodynamically favorable among all considered alkynes under different temperatures and pressures.The thermodynamic calculations are validated with experimental results,suggesting that the Gibbs free energy minimization method is effective for thermodynamically understanding the reaction network involved in the COhydrogenation process,which is helpful for the development of high-performance catalysts.

Syngas production from chemical looping reforming of ethanol over iron-based oxygen carriers: Theoretical analysis and experimental investigation

Chemical looping reforming(CLR)is a recent trend for syngas production,which has several merits compared to the conventional manner.One of the most important issues for CLR is to find low-cost material as oxygen carriers,so iron is a promising candidate.This paper contributes to testing the thermodynamic ability of iron-based oxygen carrier for chemical looping reforming of ethanol(CLRE).Iron thermodynamically investigated in temperature 100–1300℃and excess oxygen number(φ)0–4.It was found that the temperature andφhave an apparent effect on the gaseous composition produced from the process.Increases in temperature within the range of 100–1300℃enhanced syngas generated and reduced coke formation and CH4.Whereas,increasedφ,particularly at higher temperatures,had also enhanced syngas production as well as reduced coke formation.However,increasingφfor values beyond one had decreased syngas and not significantly reduced coke deposition.Moreover,an experimental investigation was carried out in a fixed bed reactor for more in-depth verification of iron ability as an oxygen carrier through using magnetite ore(mainly Fe3O4).It found that the effect of temperature on syngas production was consistent with that calculated thermodynamically,as syngas increased with raising the temperature through the CLRE.

Stress-Induced Precipitation of Fineγ'-Phase and Thermodynamics Analysis

The microstructures of a single crystal Ni-base superalloy with [001] orientation were observed by means of TEM. Results showed that the fine γ' particles were precipitated in the γ matrix channels during the tensile deformation of the alloy. Thermodynamics analysis indicated that the solubility of elements M(Al,Ta) within the γ matrix may be changed when the alloy was deformed by the external applied stress. The tensile stress reduced the solubility of elements Al and Ta so as to occur the over-saturation and agglomeration of them, which promoted the precipitation of fine γ'-phase in the γ matrix.

Fabrication of Ti_2AlC by Spark Plasma Sintering from Elemental Powders and Thermodynamics Analysis of Ti-Al-C System

A ternary-layered carbide Ti2AlC material could be synthesized by spark plasma sintering（SPS） technology using elemental powder mixture of Ti, Al and active carbon. By means of XRD and SEM, phases were identified and microscopically evaluated. The experimental results show that the main phase in the product was fully crystallized Ti2AlC with small particle size when sintered at 1200℃. The synthesis temperature of SPS was 200-400℃ lower than that of hot pressing （HP） or hot isostatic pressing （HIP）. Through thermodynamics calculations, the mechanism of Ti2AlC was studied by calculating changes of Gibbs free energy of reactions.

Thermodynamic Analysis for Carbothermal Reduction and Nitridation of TiO_2

The diagrams of stability relations（namely,Predominance area phase diagram,PAPD）of nitride,carbide and oxides in Ti-C-N-O system were plotted by thermodynamic calculation.The optimum conditions and main influence factors for the synthesis of titanium nitride and titanium carbide by carbothermal reduction in nitrogen atmosphere were discussed.

Thermodynamic Analysis on Interaction between Molten Ti Alloys and Oxide Molding Materials

A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.

Thermodynamic Calculation and Analysis of Biomass Energy Applied in the NH_3/He Absorption Refrigeration System

[Objective] The study aimed to discuss the factors influencing the application of shaping biomass energy in the NHJHe absorption re- frigeration system. [ Method] In the NHJHe absorption refrigeration system, the thermodynamic analysis of semi-gasification furnace based on sec- tional combustion technology and absorption refrigeration system was performed. [ Result] Biomass could burn cleanly and efficiently in the semi- gasification furnace, which can reduce the environmental pollution caused by the combustion of coal and other fossil fuels. The heating power of the furnace for the absorption refrigeration system could not be too high, so biomass energy and other low-grade energy can be used as heat sources, which opens up a new way for the utilization of biomass energy. [ Conclusion] Biomass energy was applied successfully in the absorption refrigera- tion system.

Thermodynamic Analysis of In-As-Sb-C-H System and Design of MOVPE Process for In(As,Sb) Semiconductor

An In As Sb C H system composed of 5 phases and 54 gaseous species is set up to simulate the MOVPE process of the In(As,Sb) semiconductor. Several phase diagram sections and the composition dependences of semiconductors on the input Ⅲ Ⅴ sources are calculated with the conditions defined according to practical MOVPE processes. The experimental data are collected and compared with the calculated results.

Experimental and Thermodynamic Analysis on Phase Equilibria of Ni-rich Region in Ni-Al-Ti System

Phase equilibria including γ,γ′,η,β and H in Ni Al Ti system were investigated by diffusion couple method and calculated with thermodynamic model.The experimental phase equilibria generally agree with ones reported till now.Regular solution and sublattice models were used in order to calculate these phase equilibria.The calculated results show agreement with experimental data.

Thermodynamic analysis and preparation of β-SiC/ZrO_2 composites

A predominance area diagram for the Zr-Si-C-O system at 1773 K was plotted according to correlative thermodynamic data. β-SiC/ZrO2 composites were prepared based on the phase diagram by carbothermal reduction of zircon （ZrSiO4） in argon atmosphere. Zircon and carbon black were mixed according to the C/ZrSiO4 mass ratio of 0.2, and with 0, 1wt% and 2wt% extra addition of La2O3. Phase evolution of the mixture was investigated at 1723-1803 K by X-ray powder diffraction, and the microstructure of the product prepared at 1803 K for 4 h was examined by scanning electronic microscope. The results show that the decomposition of ZrSiO4 and the formation of β-SIC can be promoted by increasing the heating temperature and adding La2O3. The β-SiC/ZrO2 composites can be prepared at 1803 K for 4 h in a mixture of zircon, carbon black and La2O3, and the contents of β-SIC and m-ZrO2 in the product sample with 2wt% La2O3 reach the highest values of 10.8wt% and 89.2wt%, respectively. The crystal size of the products is about 200 nm.

Thermodynamic Analysis of Hydrocarbon Refrigerants-Based Ethylene BOG Re-liquefaction System

The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane(R290), butane(R600), isobutane(R600a), and propylene(R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600 a gives the best performance, followed by(in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.

Thermodynamic analysis of carbon migration in W1-1.0C steel in plasma surface chromizing

W 1-1.0C steel was chromized at 1173 K with double glow plasma surface alloying process, and the distribution of Fe, Cr, and C contents in the chromized layer was measured using glow discharge spectrum analysis （GDA）. The behavior and mechanism of carbon migration during the formation of chromized layer were studied through thermodynamic analysis and calculation. The gradient of carbon chemical potential was regarded as the driving force of carbon migration. An equation was derived to describe the carbon content varying with the chromium content within the carbon-rich region. The calculated results from the equation approximated closely to the experimental ones.

Thermodynamic analysis of the Ti-Al-N system

Motivated by the application of （Ti, Al）N alloy compound in the coating layer, the ternary phase diagram of Ti-Al-N was analyzed by the calculation of the phase diagram （CALPHAD） technique. The isothermal sections of the Ti-Al-N ternary system were constructed and compared with the literature experimental results. The thermodynamic parameters of the Ti-Al-N ternary system and the related Ti-N and Al-N binary systems were adopted from literatures, whereas, those of the Ti-Al binary from the literatures were adjusted according to both the ternary and the binary phase equilibria. The consistency between the calculated results and the experimental data shows that considering the ternary thermodynamic relationship, the adjustments to the thermodynamic parameters of the related binaries are necessary.

Thermodynamic Analysis of Thermal Decomposition of Al(OH)_3

Thermodynamic analysis of the main reactions in the process of thermal decomposition ofAl(OH)3 was made using Temkin-Schwarzman's method and by means of regression analysis.