Based on the characteristics of structure and operation of coaxial mixer, a three dimensional mathematical model considering the flow and mixing process was developed.A novel coaxial mixer consisting of different combined inner impellers with upper and lower blades and outer wall-scraping frame was simulated and its power consumption, flow field and mixing characteristics in a highly viscous Newtonian fluid under co-rotating and counter-rotating modes were obtained.The results show that the total power consumption is less and the mixing efficiency is higher under co-rotating mode.The power consumption of outer impeller is largely influenced by combined inner impeller, which decreases with the increase of speed of inner impeller under co-rotating mode and increases under counter-rotating mode.For the combined inner impeller composed of turbine paddles, the specific volumetric mixing energy with the same Reynolds number is less when the diameter ratio between the inner impeller and stirred vessel is about 0.35.For highly viscous Newtonian fluids, the coaxial mixer with combined inner impeller with upper two-pitched-blade turbine and lower two-straight-blade turbine is better only when the Reynolds number in the mixing system is below 36; otherwise, the combined inner impeller with upper six-pitched-blade turbine and lower six-straight-blade turbine consumes less energy.

A novel continuous helical baffled heat exchanger with elliptical tubes was proposed.Numerical simulation was used to obtain shell side flow and transfer performance with ANSYS CFX.The shell-side performance was further analyzed based on the performance evaluation criterion diagram and the three-field synergy principle.Results show that in the heat exchanger, its shell-side pressure drop is reduced by 72%—80% and comprehensive heat transfer performance is improved 32%—40%, compared with traditional circular tube heat exchangers.Performance evaluation criterion diagram shows that elliptical tubes can enhance heat transfer and reduce flow resistance, since the structure of elliptical tubes brings a better synergy between velocity field and pressure filed with the synergy between velocity field and temperature field, which is favorable for heat transfer enhancement.

The objective of this paper is to study the pool boiling heat transfer characteristics of twisted tubes in a flooded evaporator.The twisted tubes are processed from common circular evaporating tubes with an outer diameter of 15.88 mm.The outer and inner diameters, wall thickness and length of the twisted tube are 19.50, 11.28, 1.09, and 3310 mm, respectively.With the same number of tubes, the twisted tube flooded evaporator(TFE) requires smaller heat exchange area than the common flooded evaporator(FE).The pool boiling heat transfer coefficients outside tubes, tube side Reynolds number Re_i, wall superheat T_sup, saturation temperature of refrigerant T_sat and heat flux q_b are considered as the key parameters.The results show that pool boiling heat transfer coefficient increases with Re_i, T_sat and q_b and decreases as T_sup increases.The case study shows that the overall heat transfer coefficient of TFE is about 1.15 times that of FE with the same heat capacity.It is proved that the application of TFE in the water-cooled screw chiller is feasible.

The knowledge and data of optical properties of skin tissue are critical for optical diagnosis of dermatosis and laser dermatology.In the wavelengths of visible- and near-infrared region, the major chromorphore for light absorption in human skin is the red cells in blood.This paper presents an experimental investigation for the effect of temperature on the optical absorption of human blood.A testing system was setup for measuring the optical absorption of human blood.In experiments, the human blood was slowly heated in a water bath from room temperature to 80℃ at a heating rate of about 0.5—1.0℃·min^-1 and the blood absorption spectra were recorded every 5℃ of increase in the blood temperature for a wavelength range of 400—1000 nm.The results at the room temperature captured three major absorption peaks well known in literature, demonstrating the validity of the system.A strong dynamic variation of the blood optical absorption characteristics with temperature has been observed, showing four different patterns of change:(1) small change when the temperature is below 50℃;(2) disappearance of selectivity of the blood absorption with wavelength at 50—58℃;(3) a dramatic increase of the absorption over the most of region at 58—65℃;(4) little change when higher than 65℃.An absorption peak is observed over the wavelength from 800 nm to 1060 nm, though the peak is fairly small and broadened significantly.Such an absorption peak in the near-infrared region may lead to the development of new lasers of long wavelength with deep penetration into the skin.

Slotted orifice is a new type of flow measuring element for gas-liquid two-phase flow measurement, Comparing with standard orifice,slotted orifice has a lot of advantages.It has less strict requirement for straight pipes upstream and downstream, its differential pressure signals are steady and there is no accumulation of liquid phase in the upstream.By analyzing local resistance of the slotted orifice, total pressure drop mainly consisted of frictional pressure drop and acceleration pressure drop.Based on flow mechanism of gas-liquid two-phase flow passing slotted orifice, frictional pressure drop and acceleration pressure drop could be calculated by momentum conservation equations and mass conservation equations, then the differential pressure drop prediction model could be developed.A series of experiments were carried out on air-water two-phase flow.According to the experimental results, mean relative error of slotted orifice with beta ratio of 0.75, 0.6, 0.5 were 6.45%, 11.06%, 12.52%.This work provided a reference for perfecting the algorithm of wet gas metering.

The process of high-pressure water penetration in water-assisted injection molding (WAIM) was simulated based on the volume of fluid method, and the filling behavior of polymer melt as well as the elongation and shear fields were studied and analyzed.The simulated results showed that the process of melt filling propelled by high-pressure water was divided into three stages, namely, initial filling, fast filling, and terminal filling stages.Remarkable elongational rate was only present in the regions near both water and melt fronts.Widely-distributed and high shear rate was present in the region near the water front, whereas water had little shear effect on the melt in the water-penetrated zone.The simulated penetration length and hollow rate of the WAIM part matched well with the experimentally determined ones.

A cylindrical spout-fluid bed(182 mm inner diameter) equipped with a 80 mm inner diameter draft tube and loaded with urea particles(2.2 mm average particle size) was used to study gas bypassing fraction of spouting gas.The effects of spout nozzle diameter, draft tube length, bed height, entrainment height, spouting velocity and fluidizing velocity on gas bypassing fraction of spouting gas were investigated. The results showed that with increasing spouting velocity, gas bypassing fraction increased first and decreased later.Gas bypassing fraction increased with increasing entrainment height,but decreased slightly with increasing static bed height.When spout nozzle diameter was less than 50 mm, gas bypassing fraction increased with increasing nozzle diameter, but remained unchanged when nozzle diameter was greater than 50 mm.When spouting velocity was low, gas bypassing fraction increased with increasing draft tube length.The introduction of a small amount of fluidizing gas could effectively suppress gas bypassing.

A small-scale natural gas liquefaction equipment was built to study the liquefaction process of LNG-FPSO and the running reliability of liquefaction cold box under sloshing conditions at sea, which is the core equipment of the LNG-FPSO. The working performance of plate-fin heat exchanger, expander and separator and the operation effect of the whole process system under different working conditions were analyzed by the surge and roll experiments of the cold box. The main conclusions are summarized as follows: the cold box and the equipment run well under the experimental sloshing conditions and the pre-cooling nitrogen expansion liquefaction process is suited to the sea condition of the target gas field; the expander installed horizontally can reduce the effect of sloshing; the balance level of the gas-liquid two-phase separation process and the evaporation rate of liquid phase is increased by rolling; arranging the process equipment at the medial axis of the ship can reduce the amplitude of sloshing, as the roll is the most influential motion on the FPSO unit.

Acoustic emission technique has many advantages because it is noninvasive and relatively inexpensive.A set of apparatus was built to measure the velocity of different-sized glass beads impacting upon a steel plate and the arising acoustic emission signal by use of a broadband piezoelectric transducer simultaneously.The impact velocity was measured by optical cross correlation velocimetry.The Welch method was used to analyze the characteristics of power spectrum of acoustic emission signal.Power spectrum mainly focused on the frequency band of 50—400 kHz and its peak moved to the lower frequency band as the particle size of glass beads was larger.Based on the Hertz-Zener theory and analytical approximation of acoustic emission spectrum, a least squares method was used in the frequency domain with the goal of calculating particle size from the experimental data.The results of the glass beads with diameters over the range of 300—400 μm and 400—600 μm agreed well with the respective results of sizing by CAMSIZER.It also provided a new way to measure particle size distribution.

Bubbly flow widely exists in a variety of chemical reaction equipment, so researching the effect of periodic force on frictional characteristics of bubbly flow in rectangular channel can support the experimental basis for studying flow characteristics under unstable state.Experiment was carried out under normal condition,and the rolling condition was set at 5?-8 s,10?-8 s,15?-8 s,15?-12 s and 15?-16 s.The experimental results showed that frictional pressure drop fluctuated periodically with rolling period and friction factor was several times of that under steady state.The fluctuation amplitude of frictional pressure drop increased with the decrease of rolling period and the increase of rolling angle.The more violent the rolling, the greater the fluctuation amplitude, while, on the contrary, the increase of flow velocity would weaken the fluctuation.Influence coefficient(ratio of rolling friction factor to steady state one) is defined to express the effect of periodic force, and an empirical correlation for influence coefficient was obtained.

Grading ring spacing size is one of the important factors affecting classification performance of a classifier.Models of vertical mill classifier with different grading ring spacing sizes were built, and flow field characteristics of different grading ring spacing sizes in vertical mill classifier SMG5500 were studied with the Fluent software.The best grading ring spacing size was obtained by making a comparative analysis of the influence on velocity field, stress field and classification efficiency at different spacing sizes.A test on the classifier was made.Simulated result showed that if grading ring spacing size was too small, most coarse particles larger than 80 μm could enter the cage, resulting in much coarser size particles in the product.If grading ring spacing size was too large, most coarse particles less than 80 μm could not enter the cage, increasing the classifier cycle load and extremely limiting classification efficiency.The vertical mill classifier SMG5500 showed optimal classification performance if grading ring spacing size was around 110 mm.

Boiling regeneration of liquid desiccant solution can reduce the dependence of desiccant air-conditioning on the outdoor environment.The study on boiling characteristics of solution is significant for the design of boiling regenerators.In this study, the pool nucleate boiling characteristics of three conventional desiccant solutions and one formula desiccant agent were investigated experimentally.For the three desiccant solutions, the boiling temperature increases with the increase of concentration; their heat transfer coefficients are lower than that of water and decrease with as concentration increases, but when the concentration increases to a limit so that small particles precipitate, the heat transfer coefficient increases.For similar mass transfer capacity, the boiling heat transfer performance of lithium bromide solution and calcium chloride solution is superior to that of lithium chloride solution.With the addition of a certain amount of calcium chloride solution, the boiling heat transfer performance of lithium chloride solution can be optimized.

Steady non-Darcian natural convection in a square cavity filled with a heat-generating porous medium is studied numerically with the local thermal non-equilibrium model, with SIMPLER algorithm in the spatial coordinates.The top and bottom walls of the enclosure are adiabatic and the left and right walls are partially heated and cooled by sinusoidal temperature profile.The results show that the temperature fields near the left wall and local Nusselt number of left wall vary periodically because of the sinusoidal boundary condition.When the parameter N for temperature fluctuations is larger enough, the streamlines, temperature fields of fluid and solid in the enclosure are similar to the results when the temperature at boundaries are uniform, while the heat transfer is enhanced by the sinusoidal boundary conditions compared with the uniform temperature boundary conditions.

The limiting-current electrochemical method,based on K₃Fe(CN)₆-K₄Fe(CN)₆-NaOH electrolyte system,is often used to investigate experimentally wall transport characteristics in power and chemical engineering fields.Accurate measurement of ferricyanide ion concentration is crucial for determining wall mass transfer coefficient.In this paper,the process of measuring ferricyanide concentration in K₃Fe(CN)₆-K₄Fe(CN)₆-NaOH electrolyte utilizing UV-VIS spectrophotometry is presented,including the measurement of absorption spectral curves,determination of the optimum absorption wavelength and the calibration of standard working curve.Results indicate that the maximum absorption (302 nm) for ferricyanide is unsuitable for concentration measurement because of the interference of ferrocyanide.The linear correlation between ferricyanide concentration and absorbance at wavelength of 420 nm is proposed and can be used to determine the ferricyanide concentration through UV-VIS spectrophotometry.In addition,the physical properties of 0.01 mol稬^-1 K₃Fe(CN)₆-0.02 mol稬^-1 K₄Fe(CN)₆-0.5 mol稬^-1 NaOH electrolyte are measured and the correlations of density,kinetic viscosity and molecular diffusive coefficient vs temperature are presented.Both the concentration measurement of ferricyanide and the physical properties of K₃Fe(CN)₆-K₄Fe(CN)₆-NaOH electrolyte may offer valuable reference for the application of limiting-current electrochemical method.

The pool boiling heat transfer performance of water in porous copper foam was investigated experimentally at room temperature and atmospheric pressure.The growth characteristics of bubble in copper foam with open cells were obtained by visual observation.The results showed that the bubble escape diameters and bubble escape frequency increased with the increase of heat flux,and the enhancement effect of copper foam for pool boiling was obtained by comparing with plain tube.A correlation for water pool boiling heat transfer coefficient in copper foam was obtained,providing a basis to further study.

A water film flash evaporation vacuum ice-making system is developed.The experiment was carried out to investigate the influence of flash evaporation pressure, thickness and initial temperature of water film on the flash evaporation process.The thickness of the water film was 15, 35, 55 and 75 mm.Initial temperature of water film ranged from 2℃ to 10℃, and flash evaporation pressure varied from 100 Pa to 600 Pa.The characteristics of the flash evaporation process were recorded using a CCD camera of the visualization system.The experimental results show that under the operating conditions, lower flash evaporation pressure leads to faster change of water film temperature at constant initial temperature of water film.Higher initial temperature of water film makes the water film temperature varies more quickly at constant pressure.As water film thickness increases, the decrease rate of water film temperature reduces.Based on the experimental results, a correlation for water film temperature with flash evaporation pressure, thickness and initial temperature of water film is presented with the maximum error of 24.19%.

Micro-structure of porous medium that approximates natural porous medium is generated stochastically by numerical method.Numerical simulation of gas diffusion in porous media is implemented with LTRT lattice Boltzmann method to investigate the effects of pore characteristics on diffusion process.It is demonstrated that diffusion processes are quite different in different porous micro-structures with the same porosity.The results also show that the dimension of the width of channels influences the diffusion.The diffusion rates increase as the channel width increases.The effect resulted from the variation of channel width and porosity in the diffusion process is far less than that for different pore structures.The influence caused by the variation of radii of filleted corners is little.These explorations provide theoretical basis and statistical support for the generation of porous media and the design and optimization of the pore characteristics of micro-reactor.

A series of V₂O₅-WO₃-TiO₂/SO₄^2- catalysts were prepared with the impregnation method using nano-TiO₂ support sulfated according to three different orders of sulfating TiO₂ support and with different acid amounts.Characterization of the catalysts with XRD, BET, FT-IR and TG-DTG showed that sulfating the catalyst support decreased the specific surface area of the resulting catalyst but did not vary its crystal form.Sulfation caused as well strong interactions between WO₃ and the sulfate of the loaded active component.Temperature-programmed activity tests demonstrated further that sulfation increased catalytic activity by increasing the acidity of the catalyst at 120—400℃.This was confirmed also with NH₃-TPD for the prepared V/Ti denitration catalysts.

Liquid-phase oxidation of toluene by air was carried out by using Co(acac)₂ as catalyst in a 1 L stirred tank reactor.The product distributions of toluene oxidation and the effect of Co concentrations on the oxidation reaction of toluene were investigated.The life of Co(acac)₂ catalyst was studied under different reaction temperatures and Co concentrations.The results showed that toluene oxidation was multiple reactions in parallel and series steps.A phenomenon of "catalyst- inhibitor" transition was found for Co(acac)₂ catalyst like other Co salt catalyst.The appropriate Co(acac)₂ dosage was 0.0044%(mass).Co(acac)₂ catalyst life changed with reaction temperature and had the longest value at 165℃.Co(acac)₂ catalyst might lose its activity easily at a lower reaction temperature (<165℃).The conversion of toluene and yield of benzoic acid could reach 19% and 80% respectively at reaction time 4 hours,reaction temperature 165℃ and Co concentration 0.0044%.Co(acac)₂ catalyst has less catalyst dosage and longer lifetime than other Co salt catalysts like cobalt acetate,cobalt naphthenate,etc.,which could slow down the scaling of cobalt oxalate during reaction.Therefore Co(acac)₂ catalyst has a good application prospect as catalyst in liquid-phase oxidation of toluene.

According to the 9-lumped kinetic model and the total kinetic model as well as the mechanism of the F-T synthesis wax hydrocracking process, a 5-lumped kinetic model was established.On the basis of the concept of isomerization factor, the experimental results combined with isomerization reaction simulation and the introduction of cracking probability function, the original 9-lumped kinetic model cracking assumption was improved.Cracking probability function made the model more close to the actual hydrocracking process.There were seven reactions in the 5-lumped reaction kinetic model.Two kinds of kinetic models were compared by using the experimental results over the catalyst consisting of platinum (0.6%,mass) supported on amorphous silica alumina modified with H-β.The average relative error between the 5-lumped kinetic model calculations and experimental values was 3.95%.When conversion was higher than 90%, average relative error was below 0.8%.From the comparison, product selectivity could be well predicted by the 5-lumped model.

Concentrations of reactant, intermediate, product were measured by HPLC during nitrolysis of DADN(1,5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane) by N₂O₅/HNO₃ at temperatures of 303, 313, 323, and 333 K.Based on the mechanism of the nitrolysis reaction(first-order consecutive reaction), the kinetic parameters were calculated from these data obtained.The activation energies were 2.3996?10⁴ J穖ol^-1 for the first step(DADN to SEX(1-acetyl-3,5,7-trinitro-1,3,5,7-tetrazacyclooctane)) and 1.6598?10⁴ J穖ol^-1 for the second step(SEX to HMX(high melt point explosive)), and the pre-exponential factors were 2.2000?10⁴ h^-1 and 6.5178?10² h^-1, respectively.The reaction rate constant is larger for the fist step than for the second one. In order to check the intermediate in nitrolysis reaction of DADN, an experiment was carried out to separate and identify the intermediate(also by-product).The results indicate that this intermediate is SEX.

Pollution of nitrogen compounds is one of the main factors that lead to eutrophication of water bodies, and biological denitrification has become an effective technology for control of nitrogen pollution.The performance of denitrifying compartmentalized anoxic reactor(CAR) was investigated with synthetic wastewater.The results showed that CAR is a high-rate reactor for nitrate removal.When influent nitrate concentration was 964.7 mg稬^-1, hydraulic retention time was 0.86 h, the nitrate removal rate(NRR) and COD removal rate(CRR) reached as high as 26.8 kg?(m³穌)^-1 and 93.76 kg?(m³穌)^-1, respectively, which all were at the top level reported in the literature.During the operation, CAR's performance was stability.In both efficiency-elevation phase and efficiency-stationary phase, relative variation coefficient and relative range of effluent nitrate are less than 9.85 and 9.07, respectively.At the same time, the relative standard deviation of effluent pH is less than 1.The good performance of CAR could be ascribed to high biomass concentration(more than 17 g稬^-1(MLVSS)) and high specific activity(more than 1.57 g NO₃^--N?(g VSS)^-1穌^-1).

The adsorption behavior of Au(Ⅲ) onto Aspergillus niger biomass was investigated in aqueous solutions.The effects of pH value, contact time, temperature and initial Au(Ⅲ) concentration on the adsorption were studied.The results indicated that Au(Ⅲ) adsorption onto Aspergillus niger was slightly pH-dependent and the pH value of 2.0—3.0 was favorable.The process was obviously accelerated with the increase of temperature in the range of 20—60℃.Au(Ⅲ) adsorption involved two stages at 20℃, corresponding to the periods before and after Au(Ⅲ) reduction and achieved equilibrium at a contact time of 24 h, while the adsorption proceeded in one stage at 30, 40 and 60℃ and achieved equilibrium at 12, 6, and 1 h, respectively.The adsorption capacity was hardly affected by temperature at lower initial Au(Ⅲ) concentrations(<233.32 mg·L^-1), while a significant increase was observed with the increase of temperature at higher Au(Ⅲ) concentrations(>367.94 mg·L^-1).Au(Ⅲ) adsorption fits the Langmuir model well, and the maximum Au(Ⅲ) uptake capacity is 185.19, 202.02, 235.85 and 277.78 mg·g^-1 at 20, 30, 40 and 50℃, respectively.The calculated thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes(ΔG⁰,ΔH⁰,ΔS⁰) reveal that this biosorption is spontaneous and endothermic and entropy increases.The adsorption process conforms to the pseudo-second-order kinetics, with the activation energy of 55.71 kJ·mol^-1.Fourier transform infrared spectra illustrate that the functional groups such as amido, carboxyl and hydroxyl may be responsible for the interaction between Au(Ⅲ) and Aspergillus niger biomass.

Separation of CO₂ from wet-process desulfurized flue gas by membrane absorption has been the subject of many studies, but investigations on the membrane process are usually carried out under laboratory conditions using pure single gases or binary gas.Under real conditions, wet-process desulfurized flue gas contains impurities, such as fine particles, H₂O and gaseous pollutant, which will influence membrane performance.In this paper, a hollow fiber membrane contactor was put into operation in the wet-process desulfurized flue gas and the effects of fine particles, water vapor and SO₂ on the performance and integrity of the membrane were investigated.The results show that fine particles deposited on the membrane surface reduce CO₂ absorption efficiency, and the stability of membranes can be improved significantly by decreasing the concentration of fine particles in the flue gas.The competitive adsorption of SO₂ is not obvious since its content is much lower than that of CO₂.It will be helpful to eliminate the water vapor by drying with back blowing gas after some period of time, so that the membrane module can work with a good stability.

Vacuum pressure swing adsorption(VPSA) is a technology for gas separation.There are some problems when it is applied to the process of biogas purification, among which is the concentration peak at the outlet of the column.To solve this problem, we use the linear driving force(LDF) model and Langmuir isothermal equilibrium to build a model and analyze the effect of CO₂ concentration in buffer tank on the purity of outlet of adsorption step.The results indicate that CO₂ enters the buffer tank in the second pressure equalization-depressurization and then the column in the first pressure equalization-pressurization, finally the concentration peak appears at the outlet of the column, and affects the CH₄ concentration.The simulation shows that in order to control the CO₂ concentration in buffer tank and improve the purity of the product, the adsorption time should be shorten as the adsorption pressure decreases.

Gas-liquid mass transfer was studied during forced sulfite oxidation in the presence of active carbon particles in a stirred tank.The influence of temperatures from 30℃ to 50℃, solid loading of fine particles from 0 to 1.0 kg·m^-3, stirring speeds from 50 to 400 r·min^-1, and particle sizes on average O₂ gas absorption rate were studied.Experimental results show that active carbon particles could improve gas-liquid mass transfer remarkably.At 30℃, with the increase of solid loading of micro-particles, the oxygen absorption enhancement factor increases to a maximum value at the solid loading of 0.6 kg·m^-3, and then decreases due to the increase of gas-liquid mass transfer resistance.For active carbon particles, the mass enhancement factor is much higher with ultrasonic processing for particle size of 1 μm.The oxygen absorption rate and absorption enhancement factor increase with the increase of stirring speed due to the acceleration of surface renewal frequency.The enhancement factor decreases as temperature increases while absorption rate increases.The result indicates that the effect of temperature on the mass transfer enhancement is stronger than the effect of fine particles.

Based on the dynamic model of ethylene slurry polymerization, a decoupling method was proposed for rigorous model calculation of molecular weight distribution(MWD).The MWD model in large scale differential-algebraic equations(DAEs) was decoupled to a moment model in small scale DAEs and chain length based MWD in large scale ordinary differential equations(ODEs).The variable decoupling method was further proposed to solve the large scale ODEs through numerical computation. Comparison of the MWD curves with Flory distribution calculation was also presented and discussed.

With the high dimension in chemical processes, it is necessary to coordinate the sub-systems to achieve optimality of the global system after decomposing the large-scale system.The on-line optimization of the whole system is decomposed into several small sub-problems, significantly reducing the computational complexity in model predictive control of the large-scale system.Decentralized model predictive control and the neighborhood optimization algorithm for distributed model predictive control based on the cascade process are not suitable for the chemical process containing interactive feedback. Therefore, by taking the system constraints into account, the global coordination algorithm was deduced based on those two optimization algorithms.The large-scale system was decomposed into sub-systems with lower dimension.Assumably there was one sample time delay communication between interacted subsystems.For each sub-system, the predictive model was constructed and the overall objective function was formulated by considering the interactions of the sub-systems.The optimal control of each sub-system was achieved.Then, the consistency for distributed model predictive control based on global coordination and centralized model predictive control was analyzed under certain conditions.The global stability of the closed loop system with distributed model predictive control based on global coordination was also obtained. The proposed algorithm was tested by simulation study of Shell heavy oil fractionator and TE process. When compared with other algorithms, it was feasible and effective.

To deal with the nonlinear characteristics of batch processes, a final product quality control strategy based on kernel partial least squares(KPLS) was proposed.KPLS model of batch process was calibrated with initial conditions, batch-wise unfolding of process data and final product quality.An estimate method based on principal component analysis(PCA) mapping was used to supplement the unknown process data, and online prediction of product quality was achieved.To cope with the final product quality control, T2 statistic was used to determine the field that KPLS model was applicable, and the model was introduced into product quality control problem as constraint to enhance the feasibility of the control strategy.Particle swarm optimization(PSO) algorithm was used to solve the optimization problem efficiently.Simulation results showed that comparing with partial least squares(PLS) model based control strategy, higher prediction accuracy was obtained with the proposed method, and various problems in product quality control could be effectively solved.

In order to achieve sustainable energy saving of heat exchanger network in the life cycle,bypasses were set in the network to increase its control degree of freedom,while a certain margin was designed to provide operating space of optimal control.To better use bypass adjustment and margin of operating space,an optimal control approach method based on dynamic model of heat exchanger network was presented and combined with existing conventional control loop,not only expanding the feasible region of optimal control,but also meeting the accuracy requirements of the original conventional control loop.The cumulative cost minimization of heat exchanger network within a certain period was considered as the objective function,while considering the impact of disturbances on heat exchanger network.To meet the process conditions,the best bypass opening in the life cycle was solved in order to achieve sustained energy saving of heat exchanger network.Closed-loop correction,iterative and rolling implementation were adopted,and optimization was based on actual conditions.A global sub-optimal solution could only be arrived at every turn.However,the actual control result could achieve the optimum.Finally,a refinery's crude oil heat exchanger network was treated as the specific study object,illustrating the effectiveness and application prospect of the presented method.

The performance of sodium lignosulfonate (SL) in industrial applications is strongly related to its adsorption characteristics on surface of solid particles.To study its adsorption mechanisms on TiO₂/water interface, the effect of temperature, pH value, ionic strength and urea on its adsorption equilibrium and kinetics were systematically investigated using residual mass fraction method.The results show that the mechanism of SL adsorption on TiO₂/water interface is surface adsorption with mono-molecular layer. Its adsorption rate constant and saturation adsorption capacity increase with rising temperature or lowering pH value, in contrast, the increase of ionic strength and adding urea reduce adsorption rate constant.The main driving force for SL adsorption on TiO₂/water interface is considered as synergistic effect of electrostatic and hydrophobic interactions as well as hydrogen bonding, and the hydrophobic interaction can significantly improve its adsorption performance.

The changes of microscopic morphology and elemental composition of Ni-Sn-P alloy coatings before and after corrosion in artificial sea water were studied with scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the corrosion products were examined with X-ray photoelectron spectroscopy (XPS).The corrosion mechanism of Ni-Sn-P alloy coatings in artificial sea water is discussed.EIS spectra and SEM showed that the corrosion resistance of electroplating Ni-Sn-P alloy in artificial seawater was better than Ni-P alloy, and the number of localized corrosion hole caused by penetration effect of Cl^- was greatly reduced.After corrosion a layer of passive film composed of SnO₂, SnCl₄, Ni₃(PO₄)₂, NiO and Ni(OH)₂ was formed on the surface of Ni-Sn-P alloy, which played an important role in improving Ni-Sn-P alloy coatings corrosion resistance.

Effect of steam and CO₂ concentration in atmosphere at both calcination and carbonation stages on CO₂ capture for calcium-based sorbent was investigated in a twin-bed calcination/carbonation cycle reaction system.Microstructure analysis from electronic scan image and N₂ adsorption/desorption was supplemented to understand mechanism affecting carbonation by steam.The results show that steam in atmosphere of both calcination and carbonation stages can enhance CO₂ capture performance of sorbents, and the optimal mass percent in these atmospheres is 10% and 5%, respectively.Effect of steam at carbonation stage on CO₂ capture was stronger for sorbent modified by alumina cement than for natural limestone.High CO₂ partial pressure at calcination stage results in severe sintering, thus low capacity of CO₂ capture.Increase of CO₂ capture performance can be achieved by using steam in the atmosphere of both calcination and carbonation stages because steam in flue gas can improve micro-porosity of these sorbents.

Slow rate of methanol oxidation and its crossover are two major challenges for direct methanol fuel cells(DMFC).The sluggish kinetics can be relieved by elevating cell temperature which, however, leads to other problems like membrane dehydration.To solve these problems, it is proposed that a methanol electrolytic reformer (MER) is combined with polymer electrolyte membrane fuel cell(PEMFC) system.Working at elevated temperature, the MER provides hydrogen for the PEMFC and is driven by power provided by the PEMFC.Essential components included in this system are described and flows of mass, enthalpy and exergy are presented.Thermodynamic analysis shows that exergy destructions occur in main components, i.e.,PEMFC and MER.The voltage of MER is an important parameter influencing the efficiency of the system. Rising temperature in MER,MER voltage required significantly decreases, but exergy losses caused by heat dissipation and heat transfer increase exponentially due to the intensified evaporation of methanol solution.To mitigate evaporation, low methanol concentration and high pressure could be necessary.When MER works at higher methanol concentration, higher pressure is required for efficient operation.The overall performance and efficiency of this system is much better than that of a DMFC.Without carbon monoxide in hydrogen generated, comparing with a competitive system in which a thermal methanol steam reformer is incorporated, this system has potentials to be built simplier.

The performance of a homemade 1.5 kW proton exchange membrane fuel cell (PEMFC) stack was evaluated under dynamic drive cycle, and the variation features (response) of PEMFC stack voltage, power and reaction parameters were investigated at various onboard operation modes.It is found that there is more obvious fluctuation of stack power and voltage at high current densities due to difference between single cells.The highest variation coefficient (C_V) is 4.23% for two dynamic drive cycle periods; the difference value between the maximum and the minimum cell voltage is 0.106 V.Data analysis indicates that PEMFC stack performance could be affected by some factors such as temperature changes of reactants and cell stack, air overflow or starvation, obvious pressure drop between anode and cathode, etc.This research could not only provide a basis for measurement and analysis of durability, but also is of important significance for parameter optimization of PEMFC running onboard

A novel integrated optimization methodology of global optimization (genetic algorithm) and local (quasi-Newton algorithm) optimization for robust and rapid parameter estimation in the initial ODEs (ordinary differential equations) systems was proposed, and it is of the advantages of both algorithms. This methodology was used successfully to estimate the parameters for dynamic variation process of dissolved oxygen(DO) in the two-step nitrification model suggested, and a high correlation coefficient was reached 0.9955.Accuracy assessment for the results estimated was realized based on a comparison of the confidence regions with those determined by Fisher information matrix and exact directly search.The assessment results indicated that using this method most of the parameters in the two-step model could be reliably estimated and only two did not, showing that it could be a novel inspection method for parameter estimation of dynamic system.Furthermore, DO simulation results could be employed as a tool of soft measurement, which could provide some process information about rapid degradation of COD, oxygen uptake rate, ammonia, nitrite and nitrate in the two-step nitrification model and related parameters estimated from DO data.

Incineration is an effective technology for municipal solid waste (MSW) disposal.However, the MSW leachate after bio-treatment still contains recalcitrant organic compounds, higher concentration of chloride ions and biogenic colloids.Their electrochemical oxidation was conducted in a newly designed filter-press electrochemical reactor.In the electrochemical oxidation process, NH₃-N could be easily removed by means of electro-generated chlorine/hypochlorite.The effects of major process parameters on the removal of organic pollutants were investigated systematically.Under experimental conditions, the optimum operation parameters are current density 65.35 mA穋m^-2, flow velocity 2.72 cm穝^-1 in electrode gap, initial chloride ion concentration 5000 mg稬^-1.The COD in the leachate could be reduced below 100 mg稬^-1 after 1 h of treatment.The kinetics and mechanism of COD removal were investigated by simultaneously monitoring the COD change and chlorine/hypochlorite production.The kinetics exhibits a two-stage kinetic model and the decrease of electro-generated chlorine/hypochlorite production is the major factor for slowing down of COD removal rate in the second stage.50% of reduction in electrode gap can result in saving more than 25% of energy consumption.A compact multi-channel bipolar structure should be taken in the design of industrial electrochemical reactors for wastewater treatment.

The process, that is destruction and recovery of nitrification performance in aqueduct by pre-chlorination, is simulated by a BAR(bio-film annular reactor) with addition of chlorine in different ways.The results showed that pre-chlorination can cause larger damage to the bio-film AOB on pipe, and give significant influence on removal of NH₄⁺-N and NO₂^--N.Higher CT value is,higher growth rate AOB during recovery stage of bio-film.The recovery was quicker for removal performance of NH₄⁺-N (8 d) than for that of NO₂^--N(10 d).Finally, it is found that there has remarkable correlation between amount of AOB and removal rate of NH₄⁺-N in pipe, and their correlation coefficient can reach as high as 92%.

Ozone was employed for degradation of dimethyl phthalate (DMP) in a simulated wastewater, and the effects of pH, DMP initial concentration, ozone dosage and reaction temperature on DMP degradation and its kinetics were investigated.The experimental results showed that the degradation efficiency of DMP was better in the range of pH 5—10, decreased with increase of DMP initial concentration although degradation total amount of DMP increased gradually, and increased with increase of ozone dosage but ozone utilization efficiency decreased.The reaction temperature had no remarkable effect on the degradation efficiency over 24℃, although below this temperature it increased with rise of temperature. The degradation efficiency could reach up to 85% at the conditions of pH 5—10, DMP concentration 14—66 mg·L^-1, ozone dosage 14—24 mg·min^-1,temperature 20—30℃ and time 40 min.The degradation of DMP by ozonation followed pseudo-first-order kinetics under the experimental conditions, and its kinetic model was determined.There was no correlation between k_obs and pH in the range of pH 2—12, because of different reaction mechanism of ozonation degradation.The k_obs increased quickly in pH 2—5 and slightly in pH 5—9, but the decrease of k_obs was observed over pH 9, and the biggest k_obs was 0.0929 min^-1.

Several mulberry twig (MT) chars were prepared by conventional pyrolysis, steam activation, and impregnation with H₂O₂, ZnCl₂ and NaCl.Adsorption performance of mercury in a simulated flue gas by MT chars were studied in a bench-scale fixed bed absorber, and the effects of steam activation, impregnation agent, adsorption temperature, and the composition of simulated flue gas, etc.on mercury adsorption performance were analyzed.The results indicated that steam activation could significantly increase surface areas of MT pyrolysis chars.Impregnation with H₂O₂ can further improve surface areas of steam activated MT chars and its pore structure. However, impregnation with ZnCl₂ and NaCl led to decrease of surface areas, D-R micro-pore and total pore volume of MT chars in some extent.The mercury adsorption capacities of MT chars impregnated with 10% and 30% H₂O₂ were 2.02 and 1.77 times of that for steam activated MT char, respectively, and that of MT char impregnated with ZnCl₂ was a little better than that impregnated with NaCl at the same impregnation concentration.The performance of mercury adsorption enhanced with increase of ZnCl₂ concentration for modified MT char.The mercury adsorption for MT600-A-ZnCl₂(5%) was 29.55 μg·g^-1, 3.37 times of that for steam activated MT char.At temperature of 60—120℃, the mercury adsorption efficiency and capacity of MT chars impregnated with H₂O₂ decreased with increase of adsorption temperature. However, the capacity of MT chars impregnated with ZnCl₂ showed an increase trend at first and then decrease, and its optimum adsorption temperature was 90℃.SO₂ and NO in the simulated flue gas showed adverse effect on mercury adsorption.Both mercury adsorption efficiency and capacity decreased slightly with increase of SO₂ and NO concentration.

GDL(gas diffusion layer) is one of the critical components of a fuel cell and its basic functions are to provide channels for diffusion of gas from fluid to catalyst layer and for drain of liquid water from catalyst layer to fluid.In order to meet service conditions, the understanding for structure-performance of GDL is very essential, such as key parameters structure, porosity, hydrophobicity, hydrophilicity, gas permeability, transport properties, water management and their roles.A mathematics model of 1D and two-phase was built for GDL in cathode of proton exchange membrane fuel cell(PEMFC).A direct numerical procedure was applied for combined equations of the model and Leverett's and Fick's laws to analyze the profiles of liquid water saturation and oxygen concentration across the gas diffusion layer.The effect of GDL characteristics, such as porosity, thickness, contact angle and absolute permeability was discussed.The results show that its hydrophobicity is helpful for removal of liquid water.The effect of contact tangle on liquid water saturation and oxygen mass transfer becomes less and GDL porosity and thickness has little effect on liquid water saturation at the hydrophobic condition, but porosity and thickness of GDL play an important role in oxygen transfer.For practical use, both GDL porosity and thickness increase, there is no significant difference for limiting current density. Tafel slope and limiting current density predicted by the model agree well with the experimental observation from literatures.

In order to improve removal efficiency of nitrogen, to enhance nitrogen removal process for low C/N ratio wastewater, and to accomplish denitrification, primary sludge was used as carbon source and NO_x^--N was added into primary fermentation system(PF) in this study.By investigating the variation of VFAs(volatile fatty acids)accumulation, NO_x^--N removal amount and VSS(volatile suspended solids) reduction, the fermentation and denitrification capacity of 4 different electron acceptor systems were contrasted.The results showed that VFAs had little accumulated for sole NO₃^--N and combined of NO₂^--N and NO₃^--N systems, while for sole NO₂^--N and anaerobic systems VFAs showed great accumulation, indicating that the use of carbon source was better for NO₃^--N and combined system.The total amount of removing electron acceptor for sole NO₃^--N, combined NO₂^--N and NO₃^--N and sole NO₂^--N systems were 1692 mg稬^-1,1330 mg稬^-1, 1223 mg稬^-1, respectively.Clearly sole NO₃^--N system had the best denitrification ability.Additionally, all these electron acceptor systems, with more than 60% VSS reduction, showed a great sludge reduction capacity, especially for NO₃^--N system, which reached about 67.9%, even though little decreased compared to the anaerobic system.In summary, for primary fermentation and denitrification system, using NO₃^--N as electron acceptor can achieve the best nitrogen removal efficiency and sludge reduction performance.

A series of iron-, copper-, zinc-, cerium-, magnesium- and aluminum-containing ternary and quaternary hydrotalcite-like compounds were prepared by coprecipitation and characterized by XRD and N₂ adsorption-desorption.All samples prepared were calcined at 700℃ for 6 h to obtain metal complex oxides whose structure and SO₂ redox performance were measured in a modified WRP-3 thermal balance.The results showed that zinc was not effective for redox of SO₂ and copper was an efficient promoter for oxidization of SO₂ to SO₃, while iron could play dual role of oxidizing and reducing promoter.In quaternary hydrotalcite-like compounds MgAlFeCu(n(Mg²⁺)/n(Al³⁺)=3, m(Fe)=8%, m(Cu)=1%) showed synergistic effect between Fe and Cu, which resulted in its higher oxidative adsorption rate, larger adsorption capacity and better reductive ability, and its total saturation adsorption capacity could be 1.33 g·g^-1 in 6 min.

Exfoliation of steam-side oxide scale in heating surface occurring during load reduction severely affects the safety of thermal power plants.Through building the finite element model for steady stress analysis,the stresses in steam-side oxide scales during unit load drop were calculated and analyzed.Ferrite alloy represented by T91 and austenitic alloy represented by TP347H were investigated in this paper. Through analyzing each of the stress components and the von Mises equivalent stress,the change of the stresses in steam-side oxide scales for both ferrite alloy and austenitic alloy during unit load drop was revealed.The possible failure modes of steam-side oxide scales for both alloys were illustrated,and it could also be concluded that the exfoliation of steam-side oxide scales for ferrite alloy and austenitic alloy was more liable to occur in the final stage and in the initial stage of load reduction respectively.

Using alkalescent functional fiber FFA-1 and resin D301 as adsorbent, some effective components in wastewater from glyphosate production such as glyphosate and glycine were recovered by process of dynamic adsorption-desorption.The dynamic adsorption conditions were optimized.4 g alkalescent fiber FFA-1, 6 g D301-C and 4 g activated carbon were packed and filled in a column,and FFA-1 column was at the bottom and D301-C column was at the top.Height/diameter ratio of both columns was 6.25.The wastewater of 200 g was pumped continuously into FFA-1 column and temperature was controlled at the range of 30℃ to 35℃.The wastewater flow rate was 1.6 ml·min^-1 for FFA-1 column and 1.3 ml·min^-1 for D301-C column respectively.The recovery efficiencies of glyphosate and glycine were 95% and 92% respectively, and the color of wastewater was from yellow to colorless.1.0 mol·L^-1 NaOH solution was used as a desorption solvent, and the desorption rates of glyphosate and glycine were 98% and 94%, respectively.The experimental results showed that alkalescent fiber FFA-1 and D301 resin had higher regeneration ability.

Ethyl chloride is an important intermediate of pesticide.It is widely used to produce organic phosphorus pesticide with high effect and low toxicity.Toxic wastewater produced in the manufacture process contains high values of chemical oxygen demand, total phosphorus, and sulfur ion.A bacterial strain SCUN which could aerobically degrade ethyl chloride wastewater was isolated from the natural water body near the wastewater discharge facility.This strain was identified as Bacillus sp.SCUN.based on its morphological observation and 16S rDNA sequence analysis.Both indole and hydrogen sulfide were not detected in the experiments of IMViC.Salt tolerance of the microorganism could reach 7%.The condition for its industrial application was discussed.It was found that at pH value of 7.0, immobilized microorganism ratio of 5%, temperature of 30℃, the microorganism showed the best growth for biodegradation.With a newly developed ternary cycle treatment, the COD removal rate approached 58.3%.

Nanofibers of perfluorosulfonic acid (PFSA),polyethersulfone (PES) and nanoparticles (SiO₂,TiO₂ and Al₂O₃) were prepared by electrospinning method from PFSA-PES-nanoparticle suspensions.The effects of nanoparticles on morphology and surface acid groups of thenanofibers were investigated.The composite nanofibers were tested in esterification of acetic acid (HAc) and ethanol (EtOH) to investigate the relationship between structures and catalytic performance.The results showed that the specific surface area of obtained nanofibers was 85.6 m²穏^-1.Nanoparticles were well distributed on the surface of the nanofibers and provided enough surface area for the reactants.The number of surface acidic centers on the surface was 71.2% of total PFSA acidic groups.Besides,the nanofibers exhibited good catalytic performance in the reactions due to improvement of activity by the nanoparticles.Moreover,these fibers could be well recovered and regenerated,and could be used as an environmental-friendly solid acid catalyst.

Ultrasonic dispersion process was utilized to modify silica sol nanoparticles with a small amount of D₄.Then in the presence of modified silica sol, miniemulsion polymerization of D₄ was conducted with DBSA as emulsifier and catalyst, and polydimethylsiloxane(PDMS)/SiO₂ nanocomposites emulsion latex was obtained.Modified silica sol particles were characterized by FTIR and TGA.The diameter and morphology of the composite latex particles were analyzed by nano particle size analyzer and TEM, respectively.Mechanical properties and thermal stability of the composite films were characterized by tensile test and TGA.The results showed that ultrasonic dispersion was an effective way to modify silica sol particles.Modified silica sol particles could be encapsulated by polydimethylsiloxane and form core-shell latex particle morphology during miniemulsion polymerization.Introduction of SiO₂ improved mechanical properties and thermal stabilities of polysiloxane composite films.

Melamine-modified lignin (MEHL) was prepared using grafting reaction from hydrolyzed lignin (EHL) by enzyme, melamine and formaldehyde, and its adsorption for silver ions was studied.The results from grafting reaction showed that content of melamine and formaldehyde had great influences on MEHL yield.High yield 83.7% for MEHL was achieved with EHL:melamine:formaldehyde mass ratio 10:6:6 at reaction temperature 90℃ and reaction time 4 h.The MEHL obtained was characterized by FTIR, TGA and elemental analysis.The results showed that melamine molecules had been grafted onto EHL chains.Nitrogen content in MEHL had obvious increase from original 0.81% to 18.55%.Furthermore, the adsorption performance for silver ions at the same conditions was much stronger for MEHL than for EHL.Its maximum adsorption capacity was up to 944.1 mg·g^-1 at optimal conditions:50 mg MEHL, initial silver ion concentration 0.16 mol·L^-1, 30℃ and 36 h.

Two new imidazoline corrosion inhibitors, 1-(2-ammonia ethyl)-2-oleic acid imidazole(A)and 1-(2-amino-thiourea ethyl)-2-oleic acid imidazole(B), were synthesized.The inhibition performance was evaluated by means of the static mass loss method and polarization curves.The mechanism of corrosion inhibition was studied by quantum chemistry calculation and molecular dynamics simulation.The results showed that both compounds A and B had good corrosion resistance in HCl solution, and they could promote both anodic and cathodic polarization of Q235 steel simultaneously.The inhibition performance of B was better than that of A.The best experimental application concentration was 150 mg稬^-1 in the range of 0 to 250 mg稬^-1.Moreover, the active regions were mainly distributed on the imidazole ring and the hydrophilic chain.The head groups could efficiently displace H₂O molecule, and corrosion was consequently restrained.Corrosion inhibition performance evaluated by the theoretic method agreed with the experimental results.

Molecular dynamic simulations were conducted to study the crystallization process of ZSM-5 zeolite from engineering perspective.The influence of temperature on radial distributions of oxygen of water were calculated, and the results indicated that the formation process of ZSM-5 zeolite might be divided into two stages, precursor formation and nucleation stage at a low temperature and crystal growth stage at a higher temperature.At a higher temperature, homogenous nucleation was suppressed, therefore, the best nucleation temperature was found at around 350 K.ZSM-5 zeolite was synthesized by using two-step procedure in accordance to the simulation results.High uniformity and high crystallinity could be obtained, which verified the simulation results.Interaction energy between template molecule and ZSM-5 zeolite at different temperatures was also calculated by using molecular dynamics.The results showed that when temperature was above 350 K, template molecules would form stronger tie with zeolite surface with increasing temperature, which might lead to intensified crystal growth and surface nucleation.SEM images of surface morphology of ZSM-5 synthesized at different temperatures confirmed this finding.

5-Phosphate pyridoxal(PPL) is the active coenzyme form of vitamin B₆, acting as a coenzyme in a multitude of biochemical processes, therefore chitosan derivatives containing pyridoxal phosphate skeleton will provide an important material for the application of chitosan in the emerging biological function material.Chitosan phosphopyridoxal Schiff base derivative was synthesized by the condensation reaction of chitosan and 5-phosphate pyridoxal in an ionic liquid, 1-butyl-3-methylimidazolium chloride(BmimCl).The product was characterized by Fourier transform infrared(FT-IR), nuclear magnetic resonance(NMR), XRD and TGA.The results showed that phosphopyridoxal group was successfully introduced onto the chitosan chain.It was found that degree of substitution of modified chitosan could reach 16.3%.