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In view of its important role as raw materials in various energy and environment fields, pure oxygen has been widely required. The present cryogenic distillation, polymeric membrane and pressure swing adsorption (PSA) air separation methods are either energy-intensive or producing non-high purity oxygen. The comparative analysis of the inorganic dense ceramic-based oxygen transport membranes (OTMs) with these traditional oxygen production technologies and the H2/O2 production by electrolysis of water shows irreplaceable advantages. The oxygen transport mechanism has been elaborated further to reveal the theoretical basis for the development of OTMs. The dual-phase membranes that have been widely studied are divided into three types according to the conduction paths of oxygen ions and electrons. Based on a review of the different types of OTM materials experienced in the past 30 years, its applications such as oxygen-enriched combustion involving H2 and membrane reactors have been discussed. Finally, challenges and future directions are analyzed according to potential industrial design directions and competitive technologies of OTMs.

Planar Thermal Source (PTS) was used to separate ethanol from Solid-State Fermented crushed straw Material (SSFM) instead of the traditional separation method of water steam in Advanced Solid-State Fermentation technology (ASSF). Complete thermo gravimetric test was done on prepared material to study the mass change rules under heating of PTS. Factors considered were temperature of PTS (T, 20–100 °C), wet content of material (θ, 0.1–0.9), ethanol concentration in wet of material (ω, 0.03–0.11). The weight order of factors on material mass change speed V was T > θ > ω, and ω can be ignored for that was an order of magnitude less important than θ and T. V linearly increases with higher T, increases by power function with higher θ. V model with T and θ was regressed. As ethanol separating from SSFM can be considered as ethanol evaporating from ethanol solution, ethanol solution evaporation model was derived. Above all, model of ethanol separation from SSFM by PTS was derived. The cost model was added. Software was programmed to calculate the separation process and its cost. The method will promote the ASSF technology to produce fuel ethanol. The study can also be reference on drying process of other crushed plant material.

Based on the cascade utilization of high-temperature waste heat and selective non-catalytic reduction (SNCR) technology, a new-type coke oven regenerator with ammonia injection space was proposed. By changing the structure and operating parameters, the high-temperature heat storage and NO emission reduction are achieved synergistically. A three-dimensional model was used to study the flow, heat transfer, and SNCR process inside the regenerator. The validity of the model was verified. Results showed that the new-type regenerator had a significant cascade utilization characteristics of waste heat. There was a competitive reaction between NH3 + NO → N2 and NH3 → NO during the coupled SNCR process. The optimal reaction temperature window was 911 ~ 984°C, and the residence time was 0.21 ~ 0.38 s. The mixing of the reductant with the flue gas and the complete contact of NH3 with NO determined high NO reduction efficiency. Furthermore, combining multiple operating parameters, a strategy was proposed to ensure the outlet NO/NH3 concentration meets the emission standard requirements.

Large-diameter buried pipelines are widely used because of their energy-saving advantage and high efficiency. In this study, an “L”-type heat pipe network was considered as research object and studied using flow–heat–solid coupling method. The ANSYS Workbench platform was used to simulate heat transfer and medium flow in the pipe network. The maximum equivalent stress and deformation of the pipe network under different displacement release conditions were calculated and compared with those under no-displacement release condition. The displacement release of the end sides did not change the stress and deformation distribution of the entire pipe network system but reduced the maximum equivalent stress and deformation, resulting in improved safety and stability of the pipeline. When the total amount of the displacement release of the inlet and outlet sections was defined, the influence of unequal end-side displacement on the stress and stress distribution of the pipe network can be neglected. Moreover, the maximum deformation gradually decreased with increasing displacement release in the inlet section and rapidly decreased with increasing total displacement release amount.

In this study, the effects of process parameters, such as gas composition and reduction temperature, were investigated. X-ray diffraction and scanning electron microscope were used to identify the products in different atmospheres. Experimental results indicate that the three-dimensional diffusion controlled model is suited to the reduction process. The compressive strength of the produced pellets gradually decreased as the temperature increased from 700 °C to 900 °C in all atmospheres. The formation of the iron whiskers made the adjacent grains loose and eventually caused the decrease of the compressive strength. The presence of H 2 atmosphere had a strong effect on the pellets reduction due to the formation of porous and fibrous iron.

Spectrally selective TiAlN/TiAlSiN/Si 3 N 4 multilayer coatings were deposited on stainless steel (SS) plate using a reactive direct current magnetron sputtering technique. In this tandem absorber system, TiAlN, TiAlSiN and Si 3 N 4 act as the main absorbing layer, the semi-absorbing layer and the antireflection layer, respectively. An average absorptance ( α ) of 0.938 and emittance ( e ) of 0.099 were achieved in coatings prepared under optimized conditions, which exhibit a fine-grained morphology and an amorphous microstructure as evidenced by SEM and XRD analysis, respectively. Absorptance and emittance data, as well as Raman spectra were collected for coatings exposed to different levels of thermal stresses (2 h in air @200 °C, 300 °C, 400 °C, 500 °C, 600 °C). These heat treated coatings showed negligible to small degradations in their selective absorbing capabilities as compared with the as-grown ones. There was no significant change of the coatings in their morphology or composition after the heat treatments, as evidenced by the SEM and Raman spectra analysis, respectively. The spectral selectivity of the coatings remained stable after a heat-treatment at 272 °C in air for 300 h.

Mass loss and direct reduction characteristics of iron ore-coal composite pellets under different technological parameters were investigated. Meanwhile, changes of iron phase at different temperatures were analyzed by using X-ray diffraction (XRD), and characteristics of crushed products were studied by using a scanning electron microscope (SEM). The results showed that heating rate had little influence on the reduction, but the temperature played an important role in the reduction process. The mass loss rate increased rapidly from 800 to 1100 °C. The reduction process can be divided into three steps which correspond to different temperature ranges. Fe2O3 began to transform into Fe3O4 below 500 °C, and FeO was reduced into Fe from 900 °C. At 900 °C, the reduction product showed a clear porous structure, which promoted the reduction progress. At 1000 °C, the metallic Fe dominated the sample, and the reduction reached a very high degree.

In this study, the kinetics of reduction in iron ore–coal composite pellets has been investigated. Kinetic parameters were estimated from thermogravimetric data. X-ray diffraction was used to identify the products obtained after heating the composite pellet to different temperatures. Experimental results indicate that the reduction process is diffusion controlled below 900 °C. There is a change in reduction mechanism above this temperature and mixed control is observed up to 1100 °C above which reduction is phase-boundary controlled. The reduction rate has also been observed to decrease with progress in reduction.

In order to optimize the pellet induration process parameters of rotary kiln, a mathematical model is developed and solved by using commercial software FLUENT. Orthogonal regression has been performed by using the simulated results of the pellet induration in rotary kiln. The functional relations between pellet induration quality and process parameters are obtained. The main parameters that affect the thermal process are also discussed. The results show that the high temperature zone is longer and the local high-temperature could be avoided while the velocity difference decreases between the secondary air and the carbon particle, which leads to more uniformed temperature distribution and better induration quality. The work gives a right direction on improving of pellet production.

Based on the analysis of heat transfer mechanics, physical and chemical change of pellet drying and preheating process in grate, the mathematical model is established and solved by three-diagonal matrix algorithm. With Visual Basic 6.0 a simulation software is developed. The model is verified by measurements at a domestic pellet plant, and the temperature distribution of pellet bed is gained. Meanwhile, the influence of different operation parameters on the pellet thermal process is studied. The results can be taken as a basis of practical production control and the grate optimizing design.

Many models of iron ore pellet induration have been developed on the basis of the first law of thermodynamics. However, the exergy analysis, well grounded on the first and second law, of the process is rare. Therefore, exergy balance test was systematically carried out on a grate–kiln, and energy and exergy analyses have been conducted to investigate irreversibility of the process. A model of iron oxide pellet exergy (IOPEM) is presented according to oxidation kinetic characteristics. It is found that the maximum effect (−6.8%) of the characteristics on the pellet exergy appears in the raised end of the kiln. The exergy efficiency of the system is determined to be 10.7% whereas its energy efficiency 59.9%, indicating a great potential for energy-saving improvements. The exergy analysis reveals exergy destruction ratio of kiln and cooler is 14.1%, and 7.7% respectively, and the largest exergy destruction (74.2%) results from the grate. No violent effect of reference environment temperature on exergy efficiency of major components is observed, indicating the grate is the major source of irreversibility. In a word, this study provides a better understanding of the energy and exergy flows of iron ore pellet induration in the grate–kiln and helps to economize energy.

The objective of this paper is to optimize the parameters of pellet drying and preheating process in grate. A mathematical model of drying and preheating is developed, and is verified by the experiments. Further, the operating parameters of wind temperature, wind speed, grate speed and bed depth etc. are investigated through the orthogonal method using the simulation results. And a relationship of drying, preheating effects and operating parameters is achieved. The results show that the optimization effect can be achieved in the given range when air velocity is about 3.0 m/s and temperature is about 300, 500, 800, and 1 100 °C in the updraft drying zone, downdraft drying zone, preheating I zone, and preheating II zone respectively. The work is help for saving energy and reducing emissions in pellet induration.

A model of three single layer back propagation(BP) artificial neural networks has been established to predict the compression strength of final pellets and dried pellets, the same as the shatter strength of the green pellets, according to the production data from SHOUGANG Mining Company. The Levenberg-Marquardt optimization arithmetic was used to train the model with the production data. After training, the error of the prediction result is less than 3%. The developed model can meet the requirement from production with a high accuracy and a wide flexibility.

Although models for general gas (e.g. natural gas) pipeline networks have been well established, research on another kind of gas networks we named gas passage networks (i.e. GPN; set that gas pass through spaces) in industry is rare. The features of the GPN are hard‐determination leakage (i.e. 24.4%), quite‐different thermophysical‐properties, more cycles and not engaging cycle energy equations directly. And the gas network of grate‐kiln‐cooler (GKC) plant used for iron ore pellets induration is belong to this type. This paper develops a mathematical model to evaluate the flow distribution in this kind. Further, a field test was systematically carried out on a GKC plant in China. At last, the result shows that good agreement was observed, indicating the validity of the model.