Ammonia (NH₃) is one of the most widely produced chemicals worldwide with a key role in the growth of global economy. Traditional ammonia synthesis by the Haber-Bosch process runs at high temperature and pressure with low hydrogen conversion, high energy consumption and severe environmental pollution. Electrochemical synthesis of ammonia has been immensely studied as it is operated at ambient temperature and pressure. The electrochemical synthesis has been improved via choosing electrolyte systems, preparing electrodes and electrocatalysts, and constructing highly efficient and stable electrochemical cells. This review summarized recent progress of electrochemical ammonia synthesis in five electrolyte systems including liquid electrolyte, proton conductor ceramic membrane, molten salts, a composite electrolyte of molten salts and ceramic membrane, and organic proton exchange membrane. Mechanism of electrochemical ammonia production, current technical status, major challenges and future directions were discussed.

In recent years, Fe₃O₄ magnetic nanoparticles have been widely explored in the fields of biomedicine, environmental protection, catalysis and electronic information. However, some drawbacks for bare Fe₃O₄ particles have limited their applications, especially in the field of biomedicine. To tackle this issue, the surface modification of Fe₃O₄ magnetic nanoparticles has been widely explored. This paper has reviewed the surface modification methods of Fe₃O₄ magnetic nanoparticles and their applications in biomedicine and environment. The future research trend and perspective of Fe₃O₄ magnetic nanoparticles are also briefly outlined.

It is difficult to prepare pure AlCl₃·6H₂O through evaporation crystallization in aluminum recovery from leaching coal fly ash by hydrochloric acid, without phase equilibria diagram for AlCl₃, CaCl₂ and FeCl₃ solution. The phase equilibria of AlCl₃+CaCl₂+H₂O, AlCl₃+FeCl₃+H₂O and CaCl₂+ FeCl₃+H₂O ternary systems at 35℃ were investigated using isothermal dissolution method. After solubility and densities were measured, phase diagram and density diagram were plotted against compositions. The phase diagrams of AlCl₃+CaCl₂+H₂O and AlCl₃+FeCl₃+H₂O had two univariant curves and two crystallization zones without formation of double salt or solid solution. Solubility of AlCl₃ decreased with increasing concentration of CaCl₂ or FeCl₃ due to common ion effect. Double salt CaCl₂·2FeCl₃·7H₂O was formed in CaCl₂+FeCl₃+H₂O ternary system. When temperature was increased from 25℃ to 35℃, phase equilibria diagrams of AlCl₃+CaCl₂+H₂O, AlCl₃+FeCl₃+H₂O and CaCl₂+FeCl₃+H₂O were all changed. Crystallization zone of AlCl₃·6H₂O in AlCl₃+CaCl₂+H₂O and AlCl₃+FeCl₃+H₂O ternary systems was enlarged and crystallization zone of CaCl₂·6H₂O was converted into crystallization zone of CaCl₂·4H₂O. Crystallization zone of CaCl₂·2FeCl₃·8H₂O in CaCl₂+FeCl₃+H₂O ternary system was converted into crystallization zone of CaCl₂·2FeCl₃·7H₂O.

Thermodynamic equilibrium state has the lowest possible energy, any non-equilibrium state is approaching equilibrium state unless existing external interactions and unified state parameters can be assigned only to the equilibrium state. Electromagnetic field can effectively enhance the heat and mass transfer processes, and it also has obvious effects on the equilibrium and stability of dielectric system. Based on the first and the second law of thermodynamics, the electric field energy is introduced into the thermodynamic differential equation, from which a new entropy function of dielectric system with the influence of electric field is deduced. Then, the equilibrium conditions and the stable conditions of dielectric systems under the action of electrostatic field are derived from the entropy criterion. The new equilibrium conditions require that the temperature, effective pressure, effective chemical potential, and electric field are uniform through the whole system. The new stable conditions require that the electric charge on the metal plates is proportional to the electric potential. This effective pressure includes mechanical effect from polarization, and the mechanical equilibrium is determined by real pressure and the electric polarization force. The effective chemical potential includes the effect of polarization potential energy, and the phase equilibrium is determined by concentration and polarization potential energy. The thermodynamic conclusions are consistent with that of electrodynamics and statistical physics, which have been confirmed by experiments.

The energy-minimization multi-scale (EMMS) model has been introduced to improve the population balance modeling (PBM) of gas-liquid flows. The energy for bubble breakup and coalescence can be obtained from the EMMS model and then used to derive a correction factor for the coalescence rate. This new model is applied in this study to simulate the bubble columns of high flow rates. Simulations using the three different models, namely, the constant-bubble-size model, the CFD-PBM model and the CFD-PBM-EMMS model, are compared with experimental data. The simulation of CFD-PBM-EMMS gives better prediction for bubble size distribution and liquid axial velocity at different heights as well as the overall and local gas holdup. The relative error of global gas holdup reduces to 5% or 15%, and the mean relative error of local gas holdup reduces to 8% or 17% for 0.16 m·s^-1 or 0.25 m·s^-1 of superficial gas velocity.

An efficient thermal management system (TMS) can significantly improve the battery life and ensure the safe operation of the battery. In the paper, a passive thermal management system based on phase change material (PCM) was designed to solve the battery heat dissipation. The composite PCM using paraffin and foam copper was employed to improve the thermal conductivity of the PCM and the experimental research on the conductivity of the composite PCM. The performance of the TMS with the composite PCM was investigated by the change of the porosity, heating power and ambient temperature. The results showed that the thermal conductivities of the composite PCM with porosity of 96%, 95% and 93% were 14.2 times, 19.2 times and 25.4 times as much as that of the pure paraffin, respectively. The TMS with composite PCM significantly reduced the temperature of the heat source and its performance was superior to the natural convection cooling. Under the conditions of the fixed heating power and the ambient temperature, the maximum temperature of the heat source declined with the decrease of the porosity. In addition, the TMS of the composite PCM can significantly reduce the temperature fluctuation caused by the change of the heating power and the ambient temperature, and improve the temperature stability of the heat source.

The heat storage rate of phase change components for a building envelope is low, because the thermal conductivity is low and the surface heat transfer is not sufficient for the phase change materials. In order to increase the rate of heat storage, the phase change component is placed under mechanical ventilation to test the regenerative rate of phase change component under different supply air temperature and air velocity conditions in the experimental platform for researching thermal performance of phase change component. Finite difference method is also used to calculate the thermal storage process of phase change component by Matlab software to expand the experimental air supply temperature conditions. It also calculates the energy consumption of the system considering the energy consumption of the fan, and an effective ventilation method is proposed. The results show that changing the supply air temperature or air velocity greater impacts on the heat storage rate of liquefaction process, but fewer impacts on the heat storage rate of regenerative process. Improving the supply air temperature or air velocity can shorten the phase change completion time, it also can improve heat flux of the component's surface. When the air velocity was 1.0 m·s^-1, and the supply air temperature increased from 34℃ to 80℃, the average heat flux of liquefaction process increased from 23 W to 322 W. The percentage of heat storage in liquefaction process decreases with the increase of air temperature, and can be constant with the increase of air velocity. In case of the phase change component is combined with mechanical air supply, it should be considered in heat storage of the system and power consumption of the fan. In the same air velocity conditions, the time of achieving maximum energy savings ultimate steady. When the supply air temperature is 80℃, the air velocity is 2.0 m·s^-1, the time is 1.6 h, the system can achieve maximum energy savings for 891.8 kJ.

Fluid flow in steam jet ejector was simulated by employing wet steam model for transonic flow. The study focused on fluid flow in mixing chamber of steam jet ejector and compared difference in simulation results between ideal gas and wet steam models. Higher entrainment ratio of steam jet ejector, smaller localized high pressure produced by shock waves near nozzle outlet and ejector inlet, and less reduction in velocity and temperature of primary steam were observed in wet steam model than in ideal gas model.

To solve blockage caused by coking in direct coal liquefaction reactors, a multi-phase model was developed to simulate two-phase gas-slurry flows around the circulation cup, which spatial flow parameters such as gas holdup were obtained. The simulation results indicated that the main driver for deposition and coking was aggregation and break-up of foams as well as foam mist blending associated with gas-liquid separation process. The relationship between extent of blocking in the circulation cup and gas holdup in downcomer showed that gas holdup in the downcomer was increased from zero to 34% as the extent of blocking was increased, leading to pump depletion. The finding on the cause of coking allowed further optimization on circulation cup structure. Simulation results showed that optimized design of circulation cup could effectively enhance gas-liquid separation with 14% gas holdup in the downcomer at extreme conditions and thus maintained stable operation. This work provides a reference for modifications on industrial equipment.

The experimental facility about the test of pressure drop and heat transfer coefficient in pump-assisted heat pipe was built for the study of characteristics during flow condensation heat transfer. The experimental investigation about characteristics during flow condensation heat transfer of R134a in pump-assisted heat pipe at different mass flux and vapor quality was conducted. The experimental results indicated that pressure drop increases with the increasing vapor quality and the mass flux. The experimental results were compared with three different pressure drop models and the conclusion that Muller-Steinhagen-Heck model can better predict the characteristics of pressure drop in the process of flowing condensation is obtained. In addition, the experimental results indicated that heat transfer coefficient increases with the increasing vapor quality and the mass flux and the growth slope of low vapor quality is higher than that of high vapor quality. The experimental results were compared with four different heat transfer models and the conclusion that Chen model can better predict the characteristics of heat transfer in the process of flowing condensation is obtained. The study provides a theoretical reference for the selection of the pump, the design of the heat exchanger, the optimization of the system and the study of two-phase flow condensation.

To research actual effect of heat transfer enhancement on pulsating heat pipe of phase change heat storage device, a pulsating heat tube type phase change heat storage device was designed and set up. The phase change thermal storage device has obvious phase change heat storage process; latent heat of phase change heat storage capacity is much greater than the sensible heat storage. Heating fluid flow increases under the same conditions have a role about the heat transfer enhancement, but the flow is not too large. Adjust the heat source temperature, the higher the temperature, the less time required for the phase change heat storage process. Compared with conventional copper tube, the heat storage device of pulsating heat pipe has saved 47% of the heat storage time in the process of heat storage and the heat transfer uniformity of the phase change heat storage device is optimized. It is verified that the heat transfer enhancement of the heat storage system is feasible by using pulsating heat pipe technology.

It is critical to understand the heat transfer characteristics of pile heat exchanger (PHE) with double spiral pipes buried in parallel so that it can be designed feasibly and operated efficiently. Therefore, a 3-D dynamic simulation model as established to study the heat transfer processes of a pile heat exchanger in which double spiral pipes and the return risers were buried in parallel. And the numerical simulation results were validated by the data obtained in an in-situ test and analytical solution of the solid cylindrical heat source model. The temperature distributions along the pipes, in the pile body and soil surrounding are illustrated and analyzed. A continuous and three intermittent heat transfer processes of this PHE were simulated dynamically. Such parameters as the dynamic outlet water temperatures of the buried parallel double spiral pipes and the heat transfer rate per unit pipe length are revealed. The temperature variations at different locations on the pile wall and in the soil surrounding along the pile depth and in radial directions are analyzed. The index of pile wall temperature recovery percentage is proposed to quantify the temperature recovery degree under different intermittent operational modes. It is found that the smaller the on-off ratio, the more significantly the temperature recovery degree along the pile wall can be achieved. But the recovery degree in each intermittent period tends to decrease as the operational cyclic increases.

In order to explore the efficient and stable catalysts hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG), the Cu-Ni/SiO₂ catalysts was prepared by hydrothermal synthesis method. The effect of different Cu and Ni mole ratio on catalytic activity was studied. By XRD, TEM and XPS characterization, the results show that the dispersion of copper and nickel species is more uniform by using silica microspheres as carriers. The ratio of Cu⁺ in the catalysts has certain influence on the yield of methyl glycolate. The reaction conditions are as follows: the hydrogen ester mole ratio 150, reaction pressure 2 MPa, reaction temperature 200℃ and the liquid space velocity 0.5 h^-1. The Cu₁Ni₁/SiO₂ catalyst showed the best catalytic performance, the conversion of dimethyl oxalate reached 90%, and the selectivity of methyl glycolate reached 80%, which has stable operation for 100 h. Above results can provide some references for the development of high catalytic activity, high selectivity, long service life and easy production of methyl glycolate.

Cordierite honeycomb ceramic (CHC) was modified by high-temperature calcination and hydrofluoric acid instantaneous etching. The framework microstructures and pore surface morphologies before and after treatment were characterized using SEM, XRD and TEM. The effect of ceramic structure on mechanical strength, morphology of carbon nanotubes, and property of complex carrier were studied. Catalytic performance of Pd/CNTs@CHC-HFn and amount of catalyst on degree of polystyrene hydrogenation were evaluated. High-temperature calcination eliminated internal pores of ceramic framework and ceramic surface became flat and dense. Instantaneous etching increased surface roughness and facilitated CNT growth on the surface. However, increase of etching cycles reduced mechanical strength of carriers as a result of over-etching into framework and CNT growth inside framework pores. CNTs growing on modified CHC-HFn surface significantly improved homogeneous dispersion of palladium and subsequently enhanced hydrogenation performance. The average particle size of palladium was 3.6 nm in the complex catalyst. At catalyst amount of 3.0 g cat·(g PS)^-1, which contained 0.378 g CNTs and 0.054 g Pd, the degree of hydrogenation for polystyrene to poly(vinylcyclohexane) reached up to 100% in 6 h reaction time.

The removal of low concentrations of toluene using non-thermal plasma (NTP) coupled with Mn-Ce/La/γ-Al₂O₃ catalysts was investigated in this study. Mn/γ-Al₂O₃ catalyst, Mn-Ce/γ-Al₂O₃ catalyst and Mn-La/γ-Al₂O₃ catalyst were prepared for the experiment. The removal efficiency of toluene, generation of O₃, CO_x selectivity for different reactors were studied. The catalysts were characterized by BET, SEM, H₂-TPR and ICP-OES. The results showed that the rare earth catalysts could effectively improve the removal efficiency of toluene and the degree of mineralization. Mn-La/γ-Al₂O₃ had the better catalytic performance than Mn-Ce/γ-Al₂O_3. The removal efficiency of toluene for the Mn-La/γ-Al₂O₃ catalyst was 72.74% under the initial concentration of toluene of 600 mg·m^-3, discharge voltage of 22 kV and gas flow rate of 6 L·min^-1. Moreover, H₂-TPR results indicated that the low-temperature activity and capability of O₃ adsorption enhanced with the loading of rare earth catalysts. The catalysts were contributed to the decomposition of O₃ and the enhancement of selectivity of CO₂ and CO_x.

The paper presents a method for preparing hybrid magnetic cross-linked enzyme aggregates (M-CLEAs) using carboxyl magnetic nanoparticles (MNP). The magnetic nanoparticle-enzyme complexes induced by electrostatic interaction between carboxyl group of magnetic particle and amino group of enzyme were separated from the solution under magnetic field, and then were cross-linked by glutaraldehyde. The traditional method of M-CLEAs preparation from amino-modified magnetic nanoparticles and the enzyme need the precipitant to prompt the separation of enzyme and magnetic nanoparticle from the solution. The method here proposed does not need the precipitant, thereof the process is greatly simplified. In this paper, the factors of cross-linking time, pH, enzyme concentration and concentration of glutaraldehyde in M-CLEAs preparation process were studied, and then the enzymatic properties of M-CLEAs were also investigated in detail. The results showed that the optimum conditions were as follows: enzyme concentration of 1 mg·ml^-1, magnetic fluid concentration of 10 mg·ml^-1, glutaraldehyde concentration of 0.25% and crosslinking reaction at pH 6.0 for 6 h. The final enzyme loading reached 80 mg·g^-1 and the activity of M-CLEAs was 50 U·mg^-1. The pH stability, thermostability and storage stability of the immobilized enzyme improved significantly, and M-CLEAs still remained nearly 60% of activity after 10 cycles.

Three mixed ionic liquids ([Choline][Pro]/[EMIm][N(CN)₂], [Choline][Pro]/[bmim][PF₆] and [Choline][Pro]/[HMIm][NTf₂]) were prepared by mixing room temperature ionic liquids (RTILs) with [Choline][Pro]. They were used to prepare SILMs by the impregnation method. Effects of operating temperature, pressure, type and content of RTILs on CO₂/N₂ separation performance of SILMs were investigated. The results showed that the CO₂ permeability of the SILMs changed between 343.3-1936.9 barrer and CO₂/N₂ selectivity was in range of 10.3-34.8. Non-equilibrium thermodynamics was used to analyze CO₂ transport mechanism in SILMs. The overall resistance showed a trend from decline to rise by increasing the proportion of [HMIm][NTf₂] in the mixed ILs, which was in accordance with CO₂ permeability in SILMs.

A new process which transforms sodium vanadate, the intermediate product during the previous vanadium-chromium co-extraction by vanadium slag sub-molten salt process, to vanadium oxide using calcification and carbonization-ammonium method was proposed. The calcification of sodium vanadate, carbonization-ammonium of calcium vanadate, and cooling crystallization of ammonium vanadate were systematically studied. The results showed that vanadium oxide prepared by sodium vanadate can be realized by calcification and carbonization-ammonium method. Vanadium recovery rate can arrive at 96.99% and the purity of product V₂O₅ over 98.53% (mass fraction). The production of high salt ammonia nitrogen wastewater was avoided from source, and environmental-friendly was realized.

A set of three-dimensional electric spiral plate-type microchannels (3D-ESPM) was designed and fabricated for the first time. The microchannel is comprised of amphiphilic copper plates and lipophilic polytetrafluoroethylene (PTFE) plates. By coupling electric demulsification and microfluidic demulsification, the microchannel can efficiently demulsify a W/O emulsion. Factors influencing the demulsification of W/O emulsion using 3D-ESPM were systematically investigated, including the height of the microchannel, the number of microchannel plates, the spiral angle of the microchannel, the electric field intensity and the flow rate of the emulsion. The results showed that demulsification efficiency increases with increasing electric field intensity, decreasing microchannel height, and increasing microchannel length. The maximum demulsification efficiency of W/O emulsion in a single pass through the 3D-ESPM reached 68% with a microchannel height of 110 μm, electric field intensity of 250 V·cm^-1, microchannel angle of 180°, microchannel number of 5, and flow rate of 2 ml·min^-1. The results showed that 3D-ESPM can intensify the demulsification of W/O emulsion.

This article studied the effects of different parameters including reaction time, pH, temperature, agitation speed, pH regulator type, dosage on the selective separation, and recovery of manganese from manganese-bearing wastewater using carbon dioxide. Optimum condition was determined by the highest recovery rate of manganese. The results showed that the recovery ratio of manganese was 99.79% with reaction time of 90 min, pH of 6.6, temperature of 45℃, agitation speed of 600 r·min^-1, and NaOH concentration of 2 g·L^-1. Mn concentration in the effluent was lower than 5 mg·L^-1, which met the third level integrated wastewater discharge standard (GB 8978-1996). The precipitate was able to meet the conforming product of manganese carbonate for industrial use standard (HG/T 4203-2011).

Spectrophotometric method based on Russell mechanism for detection of ·OH concentration in liquid has many advantages, such as low-cost, simple operation, and so on. However, low precision and poor repeatability are its main disadvantages. The reason of this method's low precision was elucidated, and a modified method was proposed. The influence of typical cations and anions on extraction of Fast Blue BB salt (FBBs) was analyzed. Key operating conditions for the modified method was determined. Based on the results, a relationship between ·OH concentration and absorbance of diazosulfones was rebuilt. The interference of FBBs in the diazosulfone extraction process is the main reason of low precision. FeSO₄ has a strong ability to hold back extraction of FBBs by extraction agent, which decreases influence of FBBs on diazosulfones detection violently. Na⁺, K⁺, NO₃^- do not have obvious effects on the detection result, while Cl^- influence is in relation to its concentration. The conditions for the modified method are: extraction time 300 s and molar ratio of FBBs to methylsulfinic acid (MSIA) is 50. The function relationship between ·OH concentration and absorbance is obtained.

With 52.40 nm PMMA microspheres as template, the templates were filled with the prepared precursor solution. The template removed by the method of temperature-programmed roasting to synthesize the porous doped Li₄Ti_4.98Zr_0.02O₁₂ ion sieve. The ion sieve was acid-modified with 0.100 mol·L^-1 hydrochloric acid and characterized by XRD, SEM, saturated exchange capacity, pH curve to test the structure of the ion sieve and adsorption performance. The results show that the prepared ion sieve has a spinel structure with a pore size of about 50 nm. The spinel structure after acid modification has not been destroyed. Ion-sieve exchange capacity is 6.43 mmol Li⁺·g^-1, and it has higher selectivity to Li⁺.

The main research topics are the recycling utilization of scandium from hydrolyzed sulfuric acid of titanium dioxide production and the separation of titanium from the scandium-loaded organic solvent. Based on the experiments of the extracting scandium from hydrolyzed sulfuric acid of titanium dioxide production in di-(2-ethylhexyl) phosphoric acid(P204)-tributyl phosphate(TBP)-sulfonated kerosene system, the extraction isotherm of scandium was plotted, which gave a foundation to carry out the experiments of counter-current extraction. The EL eluant was proposed to do with organic phase containing scandium and titanium after the experiment of counter-current extraction, which could remove titanium from the organic phase. Finally, the main influencing factors of stripping efficiency of scandium were investigated. The results show that the di-(2-ethylhexyl) phosphoric acid-tributyl phosphate-sulfonated kerosene system not only can realize the recovery and enrichment of scandium but also preliminarily separate scandium from other metallic elements, such as titanium, iron and so on. In the experiments of elution, the elution efficiency of titanium can reach 98% through three-stage countercurrent elution, with just a loss ratio of scandium for 4%, which means the better separation result of scandium and titanium. Then the stripping rate of scandium can reach more than 97% with sodium hydroxide added to the raffinate. All in all, the purity of the final product of scandium can reach 85% through the process of extraction, elution and stripping.

To address problems of point-to-point tracking control for batch processes, three different initial errors of non-ideal initial states were analyzed and studied for convergence by 2 D Roesser model within the framework of tracking control algorithm. Conditions were provided to achieve zero or a neighborhood of zero tracking control errors between system and reference trajectory at various scenarios. For these unable to achieve zero tracking errors, boundaries of final tracking errors were given. Numerical simulation validated these convergence conditions and boundaries, and assessed effect of control parameters on these boundaries.

Chemical processes are usually multivariable systems, which non-square system with more outputs than inputs is known as thin system. Till now, the most common method of designing control configuration for thin systems is to form square systems by increasing or decreasing variables such that only fully decentralized PID control could be achieved with one input pairing to one output. Some critical process variables cannot be used as controlled variables or non-critical variables cannot be included in feedback loops, so the control system often does not meet requirements. With introduction of a non-square gain array relative to average frequency, a method for designing cascade control configuration was proposed through analyzing variable pairing in thin systems. This method fully utilized feedbacks of all output variables without addition of new input variables, so system feedback was more complete and a cascade control was developed for both critical and non-critical variables. Two case study showed that this method achieved not only proper variable pairing but also good control performance especially in speed and efficiency of interference reduction.

Factor analysis (FA), which noise factors are taken into consideration, can establish probabilistic generative model by the expectation maximum (EM) algorithm. However, traditional FA (ST) index may lead to missed fault alarms by utilizing only expectation information of variables and ignoring variance information of variables that is more representative of uncertainty. The drawback of FA (ST) index was revealed by probabilistic analysis of process variables. Another important part in the modeling process was to determine number of factors, which could preserve most useful process information in the meantime of dimension reducing. A negative log likelihood probability (NLLP) index, which integrated more comprehensive probabilistic information, was proposed to overcome dilemma of insufficient information of traditional monitoring index. For the determination of number of factors, a novel global-local method was introduced so that information explanation ratios of global factors and variables over process information reached convergence simultaneously. Numerical simulation and Tennessee Eastman (TE) process study illustrated effectiveness and superiority of the proposed method.

Process monitoring technology is an effective means to guarantee operation safety and product quality of modern industrial processes. Most of traditional process monitoring methods extract data features by dimensionality reduction and require process data obeying Gaussian distribution, linearity and other conditions. Therefore, traditional methods cannot obtain preferable detection results for faults occurred under complex operating conditions. A mixture of D-vine copulas model was proposed for fault detection. First, complex correlation among process variables were directly extracted without dimensionality reduction and a statistical model of process variables was established to accurately describing nonlinear and non-Gaussian processes. Then, model parameters were optimized by expectation maximization (EM) algorithm and maximum pseudo-likelihood estimation. Finally, a generalized Bayesian inference-based probability (GBIP) index was constructed for real-time monitoring by optimized model parameters as well as theories of the highest density region (HDR) and density quantile. Application of the proposed mixture model to a numerical example and the Tennessee Eastman (TE) benchmark process illustrated effectiveness and performance in fault detection.

A recursive optimization method for data-driven operating trajectory, which was based on daily normal operation batches, was proposed for long cycle batch processes. First, original nonlinear optimization was simplified to a high dimensional linear optimization by segmented discretization and high dimensional segmented variables were transformed into lower dimensional one by PCA (principal component analysis) algorithm. Then, snapshot optimization for original operating trajectory was performed according to cosine similarity between time-segmented variables in dimensionality-reduced principal element plane and performance index of the final products. Finally, recursive algorithm for trajectory optimization was developed by consideration of changes in square errors and similarity of time-segmented variables between batches. Application to a batch crystallization process has illustrated effectiveness of this method.

Uneven-length phase data of batch processes directly affect phase modeling accuracy of data-driven multivariate statistical analysis, resulting in reduced process monitoring performance. A trajectory synchronization method of lifting wavelet package transform (LWPT) and dynamic time warping (DTW) was proposed for the uneven-length phase data of batch process. First, LWPT was used to decompose trajectories of uneven-length phase data at multiple levels of high and low frequency and extract complete time-frequency domain information. Secondly, DTW was used to synchronize coefficient matrices at different frequency bands. Finally, inverse LWPT was used to integrate synchronized coefficient matrices, to obtain the even-length phases, and to reduce the impact of the Gibbs phenomenon on data trajectory synthesis. The simulation results of penicillin fermentation batch process show that the new method calculates fast and stable with better accuracy of synchronization, which can provide reliable process data for data-driven phase modeling of batch processes.

Least squares support vector machine (LS-SVM) based on just-in-time (JIT) learning algorithm was used to build prediction model of leaching rate, when considered multi-variable multi-mode nonlinear characteristics of hydrometallurgical leaching process. Time order was introduced into selection rule of JIT learning set for the determination of modeling neighborhood of current operating point, so as to improve modelling accuracy. A cumulative similarity factor was adopted to improve real-time performance of the model and an adaptive similarity threshold was used to determine necessity of updating local model of the current operating point. The simulation results for hydrometallurgical leaching process show that the improved modeling method has high precision and good real-time performance in leaching rate prediction, which can be used in hydrometallurgical industrial production.

Temperature and pressure are important effect factors of the efficiency and quantity of CO₂ storage in the deep saline aquifers. Molecular dynamics (MD) simulation is applied to investigate the CO₂-NaCl systems in 343-373 K and 6-35 MPa, the interfacial tensions (IFT) which are obtained from the simulations are consistent with experimental results and the pressure balance point p_plateau are observed as well in this paper. Meanwhile, the interfacial tension variations with the temperature and pressure are analyzed and the reasons of p_plateau from the molecular viewpoint are explained. The results show that the pressure rise and temperature decline will increase CO₂ density and decrease IFT before p_plateau, but after p_plateau the IFT will be stable and less affected by temperature. In addition, the changes of CO₂ surface excess and the hydrate quantities with temperature and pressure showed the opposite trend compared with IFT variations, the saturation phenomena of hydrates at the interface under high pressure may be the fundamental reason of p_plateau.

The purpose of this study was to obtain three foam formulations of great foaming and stability based on response surface methodology. The factors of response were SDS, Fc-134, 6501 and mica powder #2000 through signal factor experiments. Foaming height and foam stability were the responses to study the interaction. According to Box-Benhken method, quadratic regression model was established which was significant and reliable. Using the model to predict concentration of these reagents, the optimum concentration of SDS, Fc-134 and 6501 was 2.64%, 0.096% and 3% respectively. The optimum dosage of mica #2000 was 10g. Under the optimum conditions, the predicted value of foaming height and stable time was 1550 ml and 12.8792 min respectively, meanwhile the experimental verification was 1550 ml and 12 min respectively. The error of these was 1.05% and 6.82%.Compared with un-optimized three phases foam, optimal design of three phase foam made improvement in foaming height and stable time which were increased by 14.8% and 26.3%, respectively. Results showed that optimal designed three phases foam has a greater performance of foaming and stability than the un-optimized one. The prediction error is small. It can be used for improving foaming and stability of the three phases fire-fighting foam, providing a reference for three phases foam formulation design.

Various harms on equipment and atmospheric environment, including low-temperature corrosion, fouling and blue plumes, can be caused by SO₃ in flue gas for a coal-fired boiler. To predict and control SO₃ concentration to meet the increasing demands for energy conservation and emission reduction, more accurate knowledge on the effect of the factors that influence SO₃ in flue gas is required. Thus, in present work, a kinetic model was built by optimizing the previously developed kinetic models. The effect of the factors that influence SO₃ in flue gas was studied by numerically calculating SO₃ concentration under different conditions. Moreover, SO₃ concentrations under the conditions mentioned above were measured using a perfectly stirred reactor measuring apparatus built in this work. It was found that SO₃ concentration was apparently affected by the factors, namely, the concentrations of SO₂, O₂ and H₂O, as well as temperature and residence time. SO₃ concentration was seemingly affected by the concentrations of CO and NO, while was less influenced by CO₂ concentration. In addition, SO₃ concentration underwent three stages of sharp increase, slow increase and gradual decrease with increasing residence time.

The emission of trace elements in coal-fired power plant has caused widespread concern in the world. The experimental study on the distribution and co-removal through air pollutant control devices (APCDs) and emission of trace elements (Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Ba, Pb) was conducted on a 320 MW coal-fired power plant equipped with selective catalytic reduction (SCR), electrostatic precipitator (ESP) and wet desulfurization unit (WFGD) in this study. US EPA Method 29 was used for the sampling of trace elements in flue gas. The results showed that mass balance rate of trace elements across the boiler, SCR, ESP, WFGD and the whole system was in an acceptable range. The trace elements were mainly distributed in bottom ash and fly ash with the proportion of 1.90%-27.6% and 72.3%-98.0% accounting for the sum of trace elements in bottom ash, ESP ash, stack and that removed by WFGD, respectively. The trace elements in stack and removed by WFGD accounted for little with sum in the range of 0.11%-0.66%. Co-removal rate of trace elements in flue gas across ESP and WFGD was 99.39%-99.95% and 40.39%-78.98%, respectively. The overall removal rate through SCR + ESP + WFGD was 99.79%-99.99%. The great removal rate across ESP was the main reason for high synergistic removal efficiency of APCDs. The concentration of trace elements in the stack is 0.01-12.88 μg·m^-3, while the emission factor is (0.002-4.57)×10^-12 g·J^-1. More studies on the emission of trace elements in coal-fired power plant should be carried out, which was beneficial for the establishment of emission models of trace elements in China's coal-fired power plants and the development of relevant standards.

Platanus leaf-based activated carbon (PLAC) was synthesized through high temperature carbonization and KOH chemical activation, using dry platanus leaves as raw materials. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption techniques were used to characterize the morphology, composition, specific surface area and pore size distribution of the PLAC. The cyclic voltammetric (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) characterizations were performed with a three electrode electrochemical system, to study the supercapacitor electrode performance of the PLAC. The result shows that the PLAC electrode obtained under 800℃ carbonization and KOH chemical activation has specific capacitance of 266 F·g^-1 at 1 A·g^-1, and it can remain 97.0% of the initial capacitance after 2000 cycles at 5 A·g^-1, demonstrating good electrode properties.

Three dimensional(3D) ordered macro/mesoporous titanium dioxide inverse opal (TiO₂-IO) electrodes were fabricated via a sol-gel method with polyethylene glycol(PEG2000) treatment. The effects of PEG2000- treatment on the formation of TiO₂-IO, the photovoltaic parameters and dye sensitized solar cells (DSSCs) efficiency were investigated. Macroporous templates with oval structures were prepared by using the self-assembly of monodispersed polystyrene (PS) microspheres. Titanium alkoxide precursors containing PEG2000 (as the mesopore directing agent) were infiltrated into the macroporous templates. 3D ordered macro/mesoporous TiO₂-IO films were obtained after removing the PS and PEG2000 by calcinations. This kind of 3D macro/mesoporous electrode results in a better dye absorbtivity and enhanced DSSC efficiency. The experiments demonstrate that this enhanced efficiency not only results from active sites to adsorb dye, but also may lie in the decreased characteristic impedances of the DSSCs, which is attributed to the introduction of the mesopores in the TiO₂-IO electrode. However, an excessive quantity of PEG2000 results in a drop of photoelectric conversion efficiency because of the damage of the macroporous structure with excessive PEG-treatment.

The microwave absorbing ability, compressive strength, volume shrinkage and mass loss rate of hardened calcium aluminate (CA) material at different calcination temperatures (700, 800, 900, 1000, 1100, 1200, 1300, 1400 and 1500℃) were studied. The specimens obtained at different calcination temperatures (800, 1000, 1300 and 1500℃) were characterized using XRF and XRD methods. A simple cup-shaped vessel was prepared by using CA and the microwave shock characteristics of this device were tested. The experimental results showed that the microwave absorbing ability of hardened CA decreased first and then tended to be stable with the increase of calcination temperature. After 1000℃, the microwave absorbing ability was so weak that it is no longer affected by temperature. The compressive strength of this material increased with the rise of calcination temperature, and reached the maximum at around 800℃. Then it gradually decreased and reached the minimum at 1300℃, and then stabilized after a slight increase. In the meantime, the volume shrinkage and mass loss rate increased with the rise of calcination temperature. The test results of microwave shock characteristics showed that the intensity of hardened CA basically did not change under the high-power and long-time microwave irradiation. The microwave-metal discharge test proved that this cementitious material after hardening has excellent mechanical properties and high temperature stability. In summary, hardened CA has good wave-transparent properties, excellent mechanical properties and outstanding high temperature stability, being very suitable for using in microwave heating.

Considered crystallization and demulsification phenomena of emulsion explosive (EE) matrix during storage, a percolation model for EE matrix in aging process was established by the percolation theory. Accelerated aging of EE matrix was run by freeze-thaw cycles and EE matrix after every cycle was examined by optical microscope and laser particle analyzer. The observation of crystallization process in EE matrix showed that the site percolation cluster model reflected well with real situation, which the percolation threshold p_c represented a rational indication of EE matrix aging degree. Combined with data in previous studies, the percolation model was used to analyze the critical phenomena of electrical conductivity change in EE during aging process. When cluster percentage reached to p_c, the infinite cluster was formed such that EE changed from insulator to conductor. This percolation model can be a new method for studying relationship between microstructure and macrostability of EE matrix.

In order to investigate the effects of obstacle number on the characteristics of vented gasoline-air mixture explosions, a series of contrast experiments were conducted under three different initial gasoline vapor concentrations in terms of the obstacle number, the conclusions show that: (1) There existed three typical pressure peaks denoted as p_v, p_max, and p_neg during the gasoline-air mixture explosions in a semi-opened pipe, and the magnitude of p_v was just associated with the fracture constant of the polyethylene film at the pipe exit but not with the obstacle number, while the magnitudes of p_max and the absolute values of p_neg increased with the growth of obstacle number, and the time to obtain the p_max was not fully dependent on the obstacle number. (2) During the initial flame propagation process, the flame remained a “finger-like” shape, while disturbed by the obstacles, the flame fronts became distorted, and they were accelerated to change from laminar flame to turbulent flame. And finally the flame fronts formed a “mushroom-like” shape outside the pipe, and the more obstacles, the more significant the “mushroom-like” shape. (3) The obstacles had significant effects on the flame acceleration, and the maximum flame speeds increased with the growth of the obstacle number. (4) Overpressure and flame propagation of the explosion process of gasoline-air mixture explosions had a positive feedback coupling relationship between incentives, they promoted with each other during the evolution of explosions, and the coupling relation became more significant with the growth of obstacle number. (5) The effects of obstacle number on the enhancement of p_max and maximum flame speeds for initial gasoline vapor concentrations of 1.3% and 2.1% were more obvious than that of 1.7%.