Among a variety of experimental methods to study the liquid-liquid mixing process,quantitative visualization techniques can display the mixing effects at different locations in the flow field simultaneously,as well as the evolution of the mixing process with time.The laser-induced fluorescence technique,a non-intrusive,highly accurate,easy-to-implement quantitative visualization technique,is widely used to study liquid-liquid mixing behavior in the chemical processes.This review introduces the principles and implementation methods of laser-induced fluorescence technique and discusses the progress of its applications in the investigation of both non-reactive and reactive mixing behavior.The outlook of some potential areas of this technique is also presented.

In the commercial chemical process,many primary product variables cannot be measured online,and soft sensor is an important means to solve this problem.Soft sensing modeling is the core issue of soft sensor.The relationship between soft sensing modeling and identification and nonlinear modeling is presented.The dynamic relationship between quality variables and variables that are easy to measure exists between the increments,and identification depends on incremental data,while soft sensing modeling depends on the measured data to get the relationship.Nonlinear modeling establishes the static relationship between these variables,ignoring the dynamic characteristics,which soft sensing modeling should take into account.With deeper understanding of the chemical process properties,the types and structures of soft sensing model have undergone a great change in the last decades,and soft sensing modeling method evolves from mechanism modeling to data-driven modeling,from linear modeling to nonlinear modeling,and from static modeling to dynamic modeling.The development of the soft sensing modeling method is reviewed.The advantages and disadvantages of the proposed methods are analyzed,and the applications of these methods are shown.In the end,the hot issues and the directions of development of soft sensing modeling method are presented.

Pyrolysis gasoline is an important resource of aromatics with high content of olefins,and dimethyl sulfoxide(DMSO) is a solvent that could extract aromatics from olefins selectively.Liquid-liquid equilibrium(LLE) of toluene-n-hexene-DMSO system is the basis for the extraction of aromatics from pyrolysis gasoline.In this study,LLE data of toluene-n-hexene-DMSO system at 293.15 K,298.15 K and 303.15 K were determined at atmospheric pressure,the phase diagram and plait point of this ternary system were obtained.The equilibrium data were well correlated by Hand and NRTL model.The parameters in the NRTL model for the ternary system and a formula of equilibrium data for industrial extraction were obtained.The LLE data predicted with the NRTL model are in satisfactory agreement with experimental data.The selectivity coefficients indicate that it is possible to separate toluene and n-hexene using DMSO.

Since energy issues become increasingly urgent in the world,considerable interest has focused on the utilization of low-grade waste heat.Organic Rankine cycle(ORC) is one of the effective routes to transform the low-grade waste heat to electricity.In this study,the maximum useful output work and exergy efficiency of the ORC are selected as the objective functions.10 different working fluids are chosen to comprehensively investigate and analyze the important characteristics of the two objective functions in the subcritical state.The results show that an optimal evaporating temperature exists for each working fluid,at which the useful work is the maximum.Moreover,the higher the critical temperature,the higher the optimal evaporating temperature.It is found that for the same heat source,the exergy efficiency decreases with the increase of the pinch point temperature difference.For the same pinch point temperature difference,the exergy efficiency has a maximum value when the heat source inlet temperature is twice of the pinch point temperature difference lower than the critical temperature.Otherwise,the exergy efficiency keeps increasing with the heat source temperature.These results provide some valuable guidance to optimize the ORC system and screen working fluid.

Phase equilibria in the quinary system KCl-KBr-K₂SO₄-K₂B₄O₇-H₂O at 323 K and 348 K were studied by isothermal solution saturation method.The solubilities and densities of the solution in this system were determined experimentally.Using the experimental data,the phase diagrams of the quinary system were obtained(saturated with K₂SO₄).The quinary system is a solid solution.It comprises one univariant curve and two crystallization fields(saturated with K₂SO₄),i.e.,solid solution K(Cl,Br) and K₂B₄O₇·4H₂O,and does not have invariant point.K₂B₄O₇·4H₂O has larger crystallization fields,while solid solution K(Cl,Br) has smaller crystallization fields.It is also found that KBr has the salting-out effect on KCl.The density of the solution increases with the increase of KBr concentration and decreases with the increase of KCl concentration.Compared with the stable phase diagrams at 323 K and 348 K,the crystallization fields of K₂B₄O₇·4H₂O is small at 348 K,whereas the crystallization field of solid solution K(Cl,Br) is large.

Recent studies have shown that a reasonable initial distribution can significantly reduce the transition time from initialization to reaching steady state for simulation of a riser.In this work,a series of simulations were performed to study the relationship between initial conditions and simulation efficiency.The results indicated that statistically-averaged distribution could be an effective initial distribution.Then,all the flow parameters for defining this initial distribution(i.e.pressure,gas and solids velocities,voidage) were investigated respectively for sensitivity analysis.It was found that transition time could be reduced greatly if a good axial distribution of voidage was provided at the beginning of the simulation.This finding was confirmed further by a hydrodynamical simulation of gas-solids flow in a riser with EMMS(energy-minimization multi-scale) model,in which EMMS model was used to provide a reasonable axial voidage distribution as the initial condition.The relevant results,such as solids flux,were in good agreement with experimental data.

The preparation of Curcumin nanoparticles was realized in a small stirred tank by the anti-solvent precipitation process.The influences of such factors as tank size,stirring style,initial concentration and rotation speed on nanoparticle preparation were investigated.Meanwhile,planar laser induced fluorescence (PLIF) technique was used to quantitatively measure the liquid-liquid mixing performance in the tank,and the mixing environment was found to be important for the preparation of nanoparticles.A low stirring speed in a small stirred tank with a turbine impeller could not achieve the desired mixing efficiency because of agglomeration of nanoparticles.An overly high stirring speed brought in strong shearing interaction between particles and fluid so that many particles were broken up.Overly high over-saturation in local areas would cause growth and agglomeration of particles.The optimal mixing environment with moderate process intensification was crucial to successfully prepare high quality Curcumin nanoparticles with spherical shape and narrow size distribution.

Considering the complexity and variation of mixed system in many processes in industry,a novel large-double-blade impeller with wide adaptability was developed.A computational fluid dynamics model describing the flow and mixing process was built,and the power,flow field and mixing characteristics in a stirring tank equipped with the novel impeller were simulated and analyzed.The simulation results show that in the flow field produced by the novel impeller,there are local circulating flows in the upper and lower blade zone and overall circulating flow through the whole tank.As the viscosity of mixing system increases,the fluctuations of axial,radial and tangential velocities in the flow field decrease,and its power and mixing performance remain good,which indicate that the novel impeller has a wide adaptability to flow regimes and viscosities.For the novel large-double-blade impeller,it is not beneficial to the global mixing when the feeding point is located close to liquid surface,so the feeding between the upper and lower blades is recommended in order to shorten the mixing time.The novel impeller is more efficient than the FZ impeller with the same dimension under the same power consumption per unit volume,so it is more competitive in energy conservation.The simulation will contribute a lot to the improvement and optimization of the structure and operation of the novel large-double-blade impeller.

The transition section between bottom dense zone and top dilute zone is important for fast gas-solids catalytic reactions,such as methanol to olefins(MTO).Solids concentration and fluctuation parameters in the transition section of a fluidized bed with 95 mm i.d.were measured by using reflective optical fiber probe(PV6D).The influences of superficial gas velocity and static bed height were investigated.An Eulerian-Eulerian two-fluid model that incorporated kinetic theory of granular flow and modified three-zone drag law was used to predict the flow structure in the turbulent fluidized bed.The axial and radial distributions of solids concentration were simulated by means of computational fluid dynamics(CFD).The experiments showed two axial profiles of solids distribution in the transition section:exponential and S-shaped.The maximum gradients of both axial and radial solids concentration profiles were located in the transition section,which meant that solids distribution in the transition section was much more non-uniform than that in the dilute and dense sections.The change of gas velocity and static bed height would cause a shift between exponential and S-shaped profiles,and significantly affect solids concentration in the dense region near the wall and at the bottom.Probability density distribution of local solids concentration revealed that when static bed height was small,the location of maximum voidage would gradually move from core region to annular region with increasing gas velocity,resulting in a bimodal distribution of voidage.A modified three-zone drag model was proposed by taking the effect of particle clustering into account for CFD simulation.The simulated solids concentration distribution agreed well with experimental data in the transition section except for the distributor zone.

More attention is being paid to the hydrodynamics and applications of micro fluidized beds in recent years.Considering the application of micro fluidized bed to gas-solids reaction analysis,the gas back-mixing characteristics in two beds of 10 mm and 21 mm inner diameter was studied by using the gas impulse tracer approach.The influences of bed diameter,static particle bed height,bed particle size and superficial gas velocity on the extent of gas back-mixing were investigated.It was shown that the extent of gas back-mixing increased with increasing inner bed diameter,static particle bed height and superficial gas velocity,but decreased with increasing bed particle size.The tested two micro fluidized beds that had a shallow layer of coarse particles in size of about 270 mm had both low extent of gas back-mixing and the estimated Peclet numbers for them were above 27,showing that the gas flow in these beds was very close to plug flow.This,as a consequence,verified that using micro fluidized bed for gas-solids reaction analysis could minimize the effect of gas back-mixing on reaction testing so as to get the near-intrinsic reaction kinetics.

Fine grid resolution is necessary to fully demonstrate the accuracy of two-fluid model(TFM) in predicting gas-solids flows in the riser section of circulating beds.Insufficient grid resolutions will likely lead to incorrect solutions.In most industrial applications involving large devices,it is impractical to use fine grids,and therefore,constitutive models that are suitable for the coarse-grid TFM simulations are required.It has been reported in some literatures that microscopic drag laws,such as those due to Gibilaro and Gidaspow,did not yield grid-independent solutions over the range of grid sizes investigated in some test problems.Filtered two-fluid models were developed using the results of highly resolved simulations.A filtering procedure was applied to the results of these simulations to deduce the constitutive models for the residual correlations appearing in the corresponding filtered TFM equations.These equations were appropriate for coarse-grid simulations of gas-particle flows.Using the same example studied by Mckeen and Pugsley(2003),it was first demonstrated that grid-independent predictions could be afforded by a filtered TFM,in which filtered drag and particle phase stress models were included.Then grid-independent and experimentally consistent solutions could also be obtained with filtered TFM model when filtered particle phase stress model was replaced with kinetic theory model as long as filtered fluid-particle drag force model was used.

An experiment investigation of steam flow resistance across horizontal falling film tube bundle was carried out.Experiments were performed to simulate the flow process in a large horizontal falling film evaporator of MED desalination plant under the pressure from 12 kPa to 31 kPa and at the corresponding saturated steam temperature from 50℃ to 70℃ respectively.The results indicated that pressure drop of steam flowing across tube bundle with falling film was far greater than that through a plain tube bundle.Pressure drop coefficient not only was affected by vapor Reynolds number but also changed significantly with spray Reynolds number.From the experimental results a flow resistance correlation for steam flowing across horizontal tube bundle with falling film was proposed.

Oscillating heat transfer has been widely used in engine pistons and valves,but the mechanism of heat transport is still not clearly understood,so the design of liquid cooled pistons and valves is mostly based on empirical knowledge and it is difficult to achieve appropriate heat transfer rate.In this study,a numerical simulation on oscillating heat transfer characteristics in a cavity partly filled with cooling liquid was performed by using CFD dynamic mesh method and volume of fluid(VOF) model.The relations of heat transfer coefficient to the speed and stroke of piston and fill ratio of liquid were obtained.The results indicate that the oscillation enhances the heat transfer significantly.The rotation speed is the major factor affecting heat transfer,and the heat transfer enhancement is reinforced with the increase of rotation speed and piston of stroke.When the fill ratio range of liquid is 30%—60%,the enhancement of heat transfer is remarkable,otherwise the effect of enhancement is unsatisfactory.The results are helpful to the design of pistons and valves.

To study the coupling mechanism between combustion of pulverized coal and thermal decomposition of calcium carbonate,numerical simulation was carried out aiming at an actual double-sprayed precalciner.In Euler coordinate system gas phase was expressed with the k-ε two-equation model,in Lagrange coordinate system solid phase was expressed with the discrete phase model(DPM),chemical reaction was expressed with the species transport model,and radiation was expressed with the P-1 radiation model.The predicted burn-off rate of pulverized coal was 86%,and the predicted decomposition rate of calcium carbonate was 92.9%.The data were in agreement with actual measurement.The results showed that when vertical high-velocity flue gas from the kiln met horizontal tertiary air,a major upward gas stream was created,by which coal particle stream was carried toward the outlet located on the side of the precalciner.Combustion of pulverized coal occurred mainly in the center of the lower semi-cylindrical part of the precalciner,resulting in a high temperature zone,around which calcium carbonate decomposed rapidly.

The use of gas-assisted technology is very popular in injection molding for its significant effect of improving mechanical properties and quality of products.Accordingly,the demand of gas-assisted CAE technology is also in the rising.In current CAE technology the compressibility of gas is neglected and gas or air pressure is usually imagined as a constant,such as a given value of the pressure at the inlet.But in fact,gas is strongly compressible and its pressure changes from a low value of zero to a high one before it is stabilized.It leaves unknown if these facts have any influence on the quality or mechanical properties of products.The objective of this paper is to study the complex behavior of compressible gas flow in the gas-assisted injection molding process.For simplification the real 3D flow was reduced to a 2D one based on certain assumption.A numerical simulation model of 2D transient compressible gas flow based on the characteristic-based-split method (CBS) was presented and a corresponding software with VC++ was established.Using this software a real simulation work was done.Its results could be taken as base data in further filling simulation.In addition,a pressure testing experiment was also done,and the comparison between simulation and experiment showed that the model presented in this paper was feasible.

Emission of volatile organic compounds (VOC) from building materials is a complex process of mass transfer.To have a clear picture of mass transfer characteristics, this paper first established an explicitly fully analytical model describing VOC emission behavior from dry building materials, which is applicable to emission simulation in static chamber that is most unfavorable to human health.The VOC concentration in the chamber predicted based on the mass transfer parameters in literature is in good agreement with corresponding experimental data and numerical calculation in literature.Based on this model, an experimental method is proposed for convenient, rapid and simultaneous measurement of four important mass transfer parameters for VOC emission prediction(emittable concentration C₀, diffusion coefficient D, partition coefficient K and convection mass transfer coefficient h_m) by making use of emission equilibrium or process concentration in a static chamber at a series of background concentrations. With the values of C₀, D, K and h_m for formaldehyde emission mass transfer obtained experimentally from two different medium density fiberboards, the numerically predicted results of VOC concentration in either static or dynamic chamber are coincident with experimental data.The model and method are accurate enough for emission simulation of building materials.

Caprolactam,the intermediate for the production of Nylon-6,is mainly produced through sulfuric acid catalyzed liquid phase Beckmann rearrangement of cyclohexanone oxime.This process has several disadvantages,such as the corrosion of reactors and by-production of a large amount of ammonium sulfate.These shortcomings can be prevented by vapor phase Beckmann rearrangement.In this work,the kinetics of vapor phase Beckmann rearrangement of cyclohexanone oxime to caprolactam was studied by both experiments and modeling.The results showed that the changes of catalyst activity with online reaction time could be correlated with the catalyst deactivation model developed by Wojciechowski,from which the kinetic equation and the corresponding parameters of the reaction were obtained.The results could be used to calculate deactivation rates at any online reaction time or catalyst life at the permissible lower conversion.

Polyoxymethylene dimethyl ethers as the additive of diesel oil can increase cetane number(CN) and improve fuel efficiency.It will have a broad application prospect as methanol downstream product.In a continuous flow fixed bed tubular reactor,using modified macroporous cation exchange resin as catalyst,the effects of temperature,formaldehyde/methanol molar ratio,pressure and liquid space velocity on the reaction were investigated.The single-factor and orthogonal experimental methods were applied at a broad experiment range(temperature 40—100℃,liquid space velocity 1.32—16.67 h^-1,formaldehyde/methanol molar ratio 1—4 and pressure 0.1—3.0 MPa).The orthogonal experiment design was used to investigate the integral effect of these factors on the reaction.Thus the appropriate operating conditions were obtained.At temperature 70℃,formaldehyde/methanol molar ratio 3:1,liquid space velocity 1.32 h^-1,pressure 2.0 MPa,conversion of methanol and selectivity of DMM_3—8 were 69.72% and 62.08% respectively.

There are some problems in the traditional Fenton process,such as narrower range of pH,and the difficulties to recovery Fe³⁺ and to reuse it.Based on the design idea of "immobilizing active ions and localizing acidic environment",Fe/AC catalysts were prepared by acidifying surface of activated carbon and then loading Fe³⁺ on the modified AC,to study the relationship between Fe/AC catalyst performance and preparation parameters.The results show that Fe/AC catalyst with higher activity and stability are prepared at the conditions of Fe³⁺loading amount 44.05 mg·g^-1 and calcination temperature 200℃.The degradation of bisphenol A(BPA),an environmental hormone(endocrine-disrupting chemical),was conducted using the Fe/AC catalyst prepared at these optimum conditions,and the results show that the optimal conditions for degradation of BPA are as follows:reaction time 60 min,temperature 20℃,pH 4.0 to 8.0,Fe³⁺/H₂O₂ molar ratio 0.007—0.012,and 30% H₂O₂ dosage 0.04 ml·(mg BPA)^-1.The Fe/AC catalyst prepared exhibits excellent performance for reutilization,showing greater prospect for application in treating wastewater.

The adsorption of polyethylene glycol on the surface of calcium silicate under vacuum and water environments was studied using molecular dynamics simulation.The results indicated that the adsorption ability of polyethylene glycol at(110)layer of β-2CaO·SiO₂ was stronger than other layers.Temperature had little effect on adsorption energy of β-2CaO·SiO₂ and polyethylene glycol between 343—363 K,but chain length of polyethylene glycol affected adsorption energy obviously when chain length was short.Because of adsorption energy between water molecule and polymer/crystal surface,adsorption energy of polyethylene glycol on the surface of calcium aluminate decreased.The results of distribution functions indicated that strong hydrogen bond was formed between O of polyethylene glycol and H_w of water.

Ca/HMCM-22 and CaHMCM-22 zeolite catalysts were prepared by impregnation and ion exchange respectively.The catalysts were characterized by XRD,TPD,FT-IR,and ICP.When CaSO₄ loading was less than 6.5%,CaSO₄ could be highly dispersed on HMCM-22 zeolite.A few variations in the strength and content of weak acid,and a slightly decrease of the content of strong acid were found in the two catalysts.However,the strength and content of weak and strong base on CaHMCM-22 were more than those on Ca/HMCM-22 after modification.The two catalysts exhibited good catalytic performance for the synthesis of monododecylphosphate by esterification of phosphoric acid with equimolar lauryl alcohol.The catalytic activity over Ca/HMCM-22 zeolite was higher than the catalytic activities of HMCM-22 and Ca/NaMCM-22 zeolite,CaSO₄ in synergy with acid sites and base sites of zeolite catalyst accelerated the esterification.The catalytic activity over CaHMCM-22 exchanged 3 times was also better than those of HMCM-22 and CaNaMCM-22 zeolite.Combined with the results of characterization and esterification,the presence of acidic and basic sites promoted effectively the synthesis of monododecylphosphate.

In order to effectively reduce negative influence of non-condensable gas on falling film evaporation and optimize the geometrical parameters of evaporators,a model for chemical desorption of CO₂ in the multi-effect distillation(MED)system is presented.The desorption rate of CO₂ and its influencing factors are obtained by simulating an actual MED setup.Compared with previous study and practical operation data of an MED desalination plant,the present model is proved to be reliable and has a higher accuracy.The results indicate that the evaporation temperature is the key factor influencing the chemical reaction rate,which increases as the evaporation temperature increases.The salinity and pH value play an important role in determining chemical reaction rate before the seawater temperature is saturated.The increase in the concentrations of the carbonate systems due to seawater evaporation contributes to the chemical desorption of CO₂.The desorption rate of CO₂ decreases stage by stage mainly due to the reduction of mass transfer coefficients as the evaporation temperatures in evaporators decrease.

The separation of dichloromethane,acetonitrile,water,and hexamethyl disiloxane mixture with a self-made dividing wall column(DWC)was investigated experimentally.The effects of manipulative parameters,such as azeotropic agent reflux ratio and liquid split,on the separation were discussed.According to the experimental results,the process of azeotropic distillation with DWC was simulated with Aspen Plus.The experimental results demonstrate that the separation effect is better in the range of liquid split(R_l)0.12—0.2 at vapor split(R_v) of 0.5 and entrainer reflux ratio of 3.The simulation results illustrate the optimum operation region and energy saving effect.In the optimum operation region,the thermal load of DWC reboiler is the minimum under specific requirements of separation.In the best operation region,R_l and R_v interrelate with each other.The comparison of energy consumption with that of conventional distillation sequences shows that the reboiler duty is reduced by 32.74%,the condenser duty is reduced by 33.70%,the recovery rate of acetonitrile is increased from 66.47% to 96.01%,and the cost of equipment is decreased substantially.

Commercial activated carbons were impregnated with 1 mol·^-1 nitric acid,1 mol·^-1 hydrochloric acid,and 1 mol·^-1 sulphuric acid separately,denoted as AC-N,AC-1,and AC-S,respectively.Specific surface area and pore distribution analyzer,Boehm titration and Fourier transformed infrared spectroscopy (FTIR) were used to measure the physicochemical properties of the activated carbons.Fixed-bed adsorption experiments were conducted at 283 K using toluene and methanol as adsorbates.The study shows that the acid modification can remove surface basic groups and increase the amount of surface acidic oxygen-containing groups.The relationship of the adsorption capacity of acid modification activated carbons and the specific surface area,total pore volume,micropore volume,amount of total surface acidic groups is linear.The Langmuir equation describes the adsorption of toluene and methanol onto activated carbons better than the Freundlich equation.The adsorption of methanol on activated carbons is physical adsorption.The adsorption of toluene on activated carbons is dominated by physical adsorption,but the chemical bond with surface functional groups can increase the adsorption capacity of toluene.The order of micropore diffusion coefficients of toluene and methanol on activated carbons is:AC-N>AC-1>AC-S>AC-C.The micropore diffusion coefficients of methanol are larger than that of toluene.

Adsorption process of extracted proanthocyanidins from grape seed into AB-8 macroporous resin was studied.Phase equilibrium equation and adsorption dynamic model for the process were established.Overall mass transfer coefficient,mass transfer zone length and penetration time were calculated at different flow rates and feed concentrations.The results of static adsorption show that the proanthocyanidins adsorption isotherm accords with Langmuir isotherm equation.The dynamic adsorption process of proanthocyanidins to AB-8 macroporous resin is controlled by film diffusion.The calculated penetration time agrees with the experimental results.The theoretical model could be used to supervise adsorption experiment and design.

As BOG(boil-off gas) production and LNG downstream load fluctuate frequently and sharply at LNG receiving terminal,BOG recondensation process operates with high energy consumption and instability.Through thermodynamics-based analysis of BOG processing system,a BOG multi-stage compression and recondensation process model was established,aiming at lowing energy-consumption as well as improving flexibility and operability of the BOG recondensation process.The model parameters of number of stages and single stage compression ratio were optimized by minimizing the objective function of total energy.The result showed that for a specific BOG and LNG load,the more the stages of the multi-stage compression and recondensation process system,the less the energy consumed(correspondingly,a smaller total compression ratio and a larger processing capacity of BOG); however,the energy-saving effect became more and more insignificant as the system number of system stages increased.Compared with the current one-stage system,operating flexibility of the two-stage system was improved by 12%,and compression energy was saved by more than 33% when the mass ratio of LNG and BOG was less than 10.Two-stage system was recommended for processing BOG at LNG receiving terminal.

For liquid-level control problem of gas-liquid cylindrical cyclone(GLCC) multi-phase flow device,an incremental multi-variables model predictive control(MPC) algorithm was proposed.By using state-space models with incremental control and the stair-like strategy,constrained multi-variables MPC was formulated as an optimized control problem.In order to solve the constrained optimization problem,the methods of coordinate alternation and golden section were introduced to calculate online the value of incremental control variables.This led to predictive control actions.Finally,the liquid-level control model with double-inputs and single-output of the GLCC multi-phase flow device was used to illustrate the effectiveness of the algorithm obtained.

The main function of the LNG import terminal is LNG receiving,storage and re-gasification,then supplying natural gas to power plants and city users by pipelines.Through building the dynamic models of each equipment in the LNG import terminal,and adding the necessary control systems,the process was simulated in dynamic mode,and then three operation conditions of the LNG import terminal were analyzed,including seasonal peak shaving,ship unloading and tank overpressure.During the peak shaving of LNG terminal,the power consumption of LNG send-out pump and in-tank pump changed with the same trend as the flow rate of export nature gas.Compressor power consumption and inlet flow rate of re-condenser,including BOG and LNG were affected by the ship unloading condition,which spent 13 h for the entire process.During the tank overpressure accident,which spent 15.2 h for the entire process,compressor power consumption,re-condenser pressure and inlet flow rate of re-condenser changed with the adjustment of compressor load.Finally,some suggestions on the design and operation of the LNG import terminal were proposed.

A production scheduling method was proposed for injection molding(IM) process with multiple products produced by a single machine,in order to achieve global minimum energy consumption.The total energy consumption was split into three parts.The first part was defined as switchover energy consumption,i.e.,the energy used for replacing the die and mold,changing the color or material,etc.The second part was defined as transitional energy consumption,which was determined by the regulation time for controlling the end-product with desired quality.The third part was the energy consumed during the stable production periods,which was defined as stable energy consumption.The total energy consumption model was described by a directed graph,where the nodes represented the stable production of different products and the arcs represented product switchovers.The single-machine-multi-product scheduling problem was formulated as a typical traveling salesman problem(TSP).A genetic algorithm(GA) based lexicographic optimization framework was proposed to solve such a scheduling problem.The first-layer optimization was to search the feasible process parameters that contributed to reliable production of each product.The second-layer optimization was to solve a TSP problem by finding the optimal switching path among the multiple products in order to minimize the global energy consumption. The proposed scheduling method could improve production efficiency and reduce energy consumption. Experimental results in laboratory scale tests demonstrated its feasibility and effectiveness.

In textile dyeing,using disperse dyestuff on synthetic fiber is one of the most important typical dyeing combinations.The mathematical model of this typical dyeing process was built by means of combining the existing dyeing theory and human experience through choosing the disperse dyestuff blue RSE on polyester as the representative.Firstly,three temperature-related dyeing characteristic models were built independently.Then,using the reaction rate equation,the three models were integrated to obtain the integrated model of dye uptake rate.During modeling,the grey Verhulst model,for its characteristics of less data and high accuracy,was used,so the integrated model had the advantages of being easy to determine parameters values and small amount of calculation.For the same type combinations of dye and fiber,the model could be equally applicable by changing the parameters values only.The experimental result showed that the integrated model had high accuracy and good generalization ability,and could meet the need for predicting dyeing result.

TMPAC-AlCl₃ ionic liquids with different molar ratios of TMPAC and AlCl₃ were synthesized,and their conductivities were measured at different temperatures.The study was performed by means of constant current electrolysis,and the effects of temperature,current density,stirring speed and toluene additive amount on the deposited aluminum layers were investigated.Conductivity of TMPAC-AlCl₃ ionic liquids reached a maximum with 1:2 molar ratio of TMPAC to AlCl₃ at 80℃. Better quality deposit and higher current efficiency could be achieved at the same temperature with current density of 20 mA·cm^-2 and stirring speed of 500 r·min^-1.Conductivity of the ionic liquid increased but voltage of the electrolytic cell decreased with the addition of toluene.A dense,bright,smooth and uniformly distributed deposit was obtained at current density of 23 mA·cm^-2 when volume percent of toluene was 50%.

Platinum hollow nanospheres(Pt_Hollow) were prepared in batch at room temperature by using selenium nanospheres as template,chloroplatinic acid precursor,ascorbic acid as reducing agent and SDSN as stabilizing agent,and the prepared platinum hollow spheres were used to modify glassy carbon electrode(Pt_Hollow/GC).In addition,electro-deposition platinum nanoparticles modified glassy carbon electrode(Pt_nano/GC) was prepared for comparison.The morphology and structure were characterized with X-ray diffraction,scanning electron microscopy and transmission electron microscope.Platinum hollow nanospheres had excellent dispersion and uniform size,and the diameter was about 120 nm.The shell was porous with a thickness smaller than 10 nm and was constructed by multi-dimensional and multi-level Pt atoms clusters.Formaldehyde was used as probe molecules,and the conventional electrochemical methods,including cyclic voltammetry and chronoamperometry curves were used to test the catalytic performance of Pt_Hollow/GC and Pt_nano/GC towards formaldehyde oxidation under the same electrical activity area condition.Current density at 0.64 V of Pt_Hollow/GC was 1.5 times of that of Pt_nano/GC.Oxidation potential at 0.5 mA穋m^-2 current density of the former was more negative than the latter by about 30 mV.The experimental evidence indicated that compared with Pt_nano/GC electrode,formaldehyde oxidation on Pt_Hollow/GC electrode had lower activation energy,faster reaction speed and higher catalytic activity.These could provide experimental and theoretical basis for the preparation of anode catalyst in direct formaldehyde fuel cells.

Heat pump system is an effective method for heat recovery of a treated sewage source,but biofouling on heat exchanger is still a problem to be solved,and may affect seriously efficiency and security of the system.By long term monitoring and 16S rRNA identification,two major bacteria genus,Bacillus sp. and Aeromonas sp.,were selected for multi-strain biofouling experiment of a model fluid in laboratory.By the experiment of foul growth performed on a purpose made channel at various bacteria ratios and nutrient levels,the regular patterns of single and mixed microbe growth of Bacillus sp. and Aeromonas sp. were revealed,their synergy and inhibition interaction summarized,and the effect of nutrient levels on their growth mechanism and interaction also investigated.The results indicated that the Bacillus sp. has strong ability in biofouling,in high multiple rates,and high tolerance to poor nutrient level.The biofouling of Aeromonas sp. is weak relatively,but high secretion rate that may help for the synergy growth with Bacillus sp.Their synergy and inhibition interactions co-exist and dominate in turn under different growth stage and condition.

The pyrolysis characteristics of two different kinds of refuse-derived fuels(RDF) were investigated using thermogravimetric analysis-Fourier transform infrared spectrometer(TG-FTIR).It was found that the pyrolysis characteristics of two RDFs were similar.The pyrolysis process could be divided into three main stages,corresponding to the decomposition of biomass components(220—430℃),plastic substances(430—520℃) and carbonates(>650℃).The Coats-Redfern method was used to analyze the apparent kinetic parameters of the first two stages,and the results showed that the activation energy was higher for the middle-temperature stage than for the low-temperature stage.By FTIR analysis,it was found that the major volatile gases released from the two RDFs were similar,mainly including H₂O,CO₂,CO,CH₄ and other hydrocarbons.The release of gaseous pollutants was paid special attention.The emission of HCl is completed at the low temperature stage(230—400℃).In contrast,the release of NH₃ begins at 260℃ and goes through a much wider temperature range,and there is still a small amount of NH₃ release at much higher temperature.In pyrolysis condition investigated,it was surprised to detect large amount of SO₂,mainly released in the temperature range of 300—600℃.

Chemical oxidation by Fenton's reagent of a reactive azo dye (Brilliant Red X-3B) had been optimized using experimental design.The variables considered were pH,temperature as well as initial concentrations of hydrogen peroxide and ferrous ion.The results show that initial pH value has the biggest effect on TOC removal and decoloration.Based on orthogonal experiment design,single factor experiment was conducted to optimize reaction conditions.The results reveal that the optimum reaction conditions obtained are pH 3,hydrogen peroxide(30%) 2.5 mmol稬^-1,C(H₂O₂)/C(FeSO₄) ratio 10,and the rates of decoloration and TOC removal for simulated wastewater are 98.93% and 48.81%,respectively.Furthermore,the effect of temperature on the TOC removal rate is remarkable,and the decolorization rate follows second-order kinetic model.Using Arrhenius equation,the activation energy calculated for degradation of reactive Brilliant Red X-3B in Fenton reaction system is about 107 kJ穖ol^-1.

For treatment of light pollution water with low turbidity,the investigation was made on coagulation efficiency of Al₂(SO₄)₃,AlCl₃,and PACl as well as effect of potassium permanganate on efficiency of alum-based coagulants and on content of residual particle aluminum(Al_P) and dissolved one(Al_D),and a relativity analysis also made on between form of Al_P and removal performance.The results show that there is similar coagulation efficiency for Al₂(SO₄)₃ and AlCl₃,because their ability of charge neutralization is better than PACl.However,for removal of turbidity and dissolved organics,PACl is better than Al₂(SO₄)₃ and AlCl₃.The effect of KMnO₄ on zeta potential of AlCl₃ and PACl flocs weakens gradually with increase of its dosage,while that of KMnO₄ on removal of turbidity and dissolved organic matter goes up,mainly in the stage of charge neutralization.Moreover,the content of Al_D and Al_P,mainly Al_P, decreases obviously by use of KMnO₄.At the same dosage of these coagulants,there is a positive correlation between the content of Al_P and residual turbidity,but content of Al_D is influenced by dosage of both KMnO₄ and coagulants,especially,is relatively stable when sweep flocculation is in the ascendant.

Based on experimental results,kinetics and two-film theory,the mass transfer-reaction kinetics was experimentally studied for NO removal using a combination process of UV/H₂O₂ oxidation and CaO absorption(UV/H₂O₂-CaO process) in a lab-scale UV-bubbling column reactor.The mass transfer-reaction process of NO absorption was analyzed to determine its rate controlling step and some measures that can effectively strengthen NO absorption,and some key kinetic parameters were measured and a theoretical model for NO absorption was established.The results indicate that under experimental conditions,the rate of NO absorption almost linearly increases with NO concentration.With increase of H₂O₂ and CaO concentrations,the efficiencies of NO removal increase greatly at first,and then its change is small.The absorption of NO by combined UV/H₂O₂-CaO process follows pseudo-first-order kinetics.The NO absorption rate can be effectively strengthened by increases of turbulence in gas phase body,gas-liquid contact area and NO partial pressure.The values calculated from the theoretical model of NO absorption are in good agreement with the experimental values.

To understand structure change of lignin-carbohydrate complexes (LCCs) in kraft cooking process,it was separated firstly out from the powder of rise straw by Björkman procedure,into which coniferyl alcohol glucoside with ¹³C-label had been rejected,and its structure was determined by ¹³C NMR and FT-IR spectra.The result showed that lignin was linked to carbohydrate by benzyl ether,ester and α-ketal bonds,and β-O-4 structure was the main structure of lignin in LCC.Then,the LCC obtained with and without ¹³C-label was cooked by kraft method and isolated respectively,to get lignin-carbohydrate complex-kraft lignins(LCC-KLs).The LCC-KLs structures were determined by ¹³C NMR and FT-IR spectra,and the intensities of α-carbons increased markedly for the sample with α-¹³C-label.The result showed that most of benzyl ether bonds and ketal linkage between lignin and carbohydrate were broken in pulping,but there still were bits of ketal linkage.Main structures of LCC-KL were found to be β-O-4 units,with a small number of phenylcoumaran units,pinoresinol units and β-1 units.

The tests of mercury adsorption on Tai-Xi activated coke were conducted in an adsorption system of fixed-bed reactor.The effect of inlet mercury concentration and temperature on adsorption efficiency(removal of mercury)was studied using a simulated flue gas that was prepared by mixing flue gas component CO₂,N₂,O₂,NO and Hg⁰ vapors came from a permeation tube.The results show that there is similar shape of adsorption curve for different initial mercury concentrations and efficiency of mercury removal increases with increase of inlet mercury concentration.The initial port of breakthrough curve shows that the adsorption rate is rapid,then slow and slow until to adsorption saturation.The uptake process of mercury by activated coke can be well fitted by a pseudo-second order kinetics model,indicating that for CO₂/N₂/O₂/NO/Hg⁰ system,the adsorption of mercury on the activated coke takes mainly place by chemical adsorption or chemical reaction.The optimal temperature is 423 K for the best mercury removal.The Bangham equation can be applied to describe the adsorption behavior at different operation temperature,and the adsorption rate constants at different temperature follow as k_423K>k_463K>k_403K.

It is difficult to achieve biological deep denitrification of wastewater due to low content of biodegradable organic matter in tail water from sewage treatment plant.If the tail water discharged into rivers,the eutrophication could be produced due to higher concentration of total nitrogen.Therefore,the study on deep denitrification technology is of important significance for tail water treatment.In this paper,the total nitrogen(TN) removal efficiency of a catalytic electric-oxidation technology and its influence factors,such as electric-current density,HRT,influent pH,etc.,were studied and analyzed.The results showed that total nitrogen can be decreased to 11.91 mg·L^-1 from 26.40 mg·L^-1(54.9%),NO₃^--N to 4.90 mg·L^-1 from 18.03 mg·L^-1(72.8%) by the catalytic electric-oxidation technology at conditions of current density 32.67 mA·cm^-2,pH 6.25—7.02,and HRT 30 min.The NO₃^--N removal is dominating in the TN removal of tail water from urban wastewater treatment plant.The results indicate that TN of tail water can be removed efficiently by this technology.The catalytic electric-oxidation technology is of the advantages of operation stability and shock resistance etc.,and could be a basis for advanced nitrogen removal of tail water from wastewater treatment plant.

Highly dispersed Pd/Fe nanoparticles were prepared by using ultrasound-assisted liquid phase reductive method,and used for reductive dechlorination of 4-chlorophenol(4-CP).The affecting factors and degradation kinetics were investigated.The experimental results showed that:obvious modification was achieved on the particle size,most of them less than 100nm,and on specific surface areas,increased 43.42%.The efficiency of 4-CP reductive dechlorination was up to 97% on the Pd/Fe nanoparticles with Pd mass fraction 0.2% and its dosage 2.5 g·L^-1 at the conditions:time 300 min,initial 4-CP concentration 20 mg·L^-1,pH value 3.0,and reaction temperature 30℃.The degradation reaction of 4-CP followed pseudo-first-order kinetics and the apparent pseudo-first-order kinetics constant was 1.76×10^-2 min^-1.

A new kind of flotation system with high dissolved air content was developed through investigating the fundamental principles of oxygen transfer in water and hydromechanics.The air dissolving and releasing performance of the new flotation was studied based on the clean water aeration and coagulation-flotation experiment of reactive yellow KE-4RN simulated waste water.The results showed that the new flotation system had such advantages as high oxygenation capacity,low working pressure,high dissolved air content,small bubble size,no packing and low energy consumption.In the experiments of oxygen-free water aeration,the mass transfer coefficient of O₂ K_La(20) was 0.4151 min^-1.Meanwhile the content of saturated dissolved oxygen in clean water was high(more than 11.00 mg·L^-1) and the produced micro-bubbles had a mean diameter of 38 μm.A removal rate of 99.0% could be achieved for reactive yellow KE-4RN simulated waste water by coagulation and air flotation under the experimental conditions of dye concentration 100 mg·L^-1,dosage of polymerization aluminum chloride(PAC)800 mg·L^-1 and dosage of polyacrylamide(PAM) 20 mg·L^-1.

The novel process producing magnesium metal using vacuum aluminothermic reduction,which utilizes dolomite and magnesite as raw materials and aluminum powder as reductant,produces reducing slag containing-rich CaO·2Al₂O₃.The reducing residue can be solved by a mixture solution of sodium hydroxide and sodium carbonate,and a solution of sodium aluminate is produced which can be decomposed by CO₂ to obtain aluminum hydroxide.For the production process of aluminum hydroxide,effects of process parameters on leaching rate of alumina are investigated systematically and the performance of aluminum hydroxide obtained was detected.The results show that the alumina leaching rate from the residue is above 85% under the conditions of NaOH concentration 80 g·L^-1,Na₂CO₃ concentration 110 g·L^-1,leaching temperature 95℃,leaching time 120min and L/S 6.Whiteness of aluminum hydroxide obtained carbonation precipitation at 50℃ is over 98,and average particle size is 26.98μm.

A new type of comonomer EDA-di(diacetone propionamido) was synthesized by the Michael addition reaction using diacetone acrylamide and ethanediamine as raw materials.The structure of the monomer was verified by ¹H NMR and ¹³C MNR.Polyurethane dispersions(PUDs) were synthesized by the prepolymerization process using polyneopentanediol adipate(PNA) as soft segment,isophorone diisocyanate(IPDI) as hard segment,dimethylolpropionic acid(DMPA) as hydrophilic monomer,EDA-di(diacetone propionamido) as functional monomer.Research was done to know the influence of monomer on polyurethane dispersions.The result showed that particle size increased as the content of monomer increased while viscosity decreased.The mechanical property was improved through the room temperature self-crosslinking of adipic dihydrazide(ADH).

Hydrophobic copper phthalocyanine blue organic pigment (PB) can be effectively encapsulated by co-poly(styrene-acrylate)via in-situ micro-suspension polymerization.In order to adjust and control the morphology of pigment microcapsules,the effects of homogenization shear rate,agitation speed,dispersant TCP amount and pigment concentration on the particles size and size distribution of polymerization products were investigated.It was found that there was a critical agitation speed of 250 r·in^-1 for achieving a stable size and size distribution of dispersed phase during polymerization.TCP amount had a significant effect on the stability of micro-suspension system but a limited effect on particle size control.Homogenization shear rate played an obvious role in controlling particle size,while the effect of pigment concentration on particle size was not obvious.Thus a series of pigment microcapsules with controllable particle size,narrow distribution and high pigment content could be obtained.

Leakage and explosion accidents are often caused by gasket aging,perforated corrosion of pipeline,weld crack,outside force bump,poor management and other reasons in applications of liquefied natural gas(LNG).Research on LNG leak diffusion process will greatly reduce personal and economic loss.A study on LNG diffusion process is conducted for continuous leakage.The diffusion process is divided into two stages,heavy gas diffusion in initial stage and passive diffusion in the following stage.The first stage is described by SLAB steady plume dispersion model and the second stage uses Gaussian plume model.The transformation of heavy gas diffusion and passive diffusion is indicated by a stage transformation criterion.For vertical jet source,the releasing gas rises because of its initial momentum before gravitational diffusion.The rising height of plume is calculated.The mathematical model of LNG diffusion process is set up and used to simulate the diffusion of vertical leakage LNG under two environmental conditions.The concentration profile,temperature profile and other characteristic parameters of mixing clouds after leaking are calculated.The heat and mass transfer between LNG and the environment is analyzed.The influence of heavy air on the diffusion process is explained.These results are helpful in determination of damage range of accident,evacuation of people and guidance of rescue work.