Among current air conditioning refrigerants, R410A and R407C are the main alternative refrigerants of R22. Their ODP is zero, but their GWP is relatively high, with a negative impact on the environment. For the selected mixed refrigerant composed of mass fraction of 40% of R1234ze and 60% R152a (represented by NCUR01), its theoretical analyses according to REFOROP9.0, analyzing its environmental impact index, its temperature glide characteristics, theoretical thermodynamic cycle performance, thermodynamic properties, safety and lubricants, and other factors are carried out and compared with R22, its major alternative refrigerants R410A and R407C. The results show that the mixed refrigerant has very small impact on the environment, presents similar saturation pressure line to that of R22, and has a lower discharge temperature and a higher COP. The discharge temperature of NCUR01 is 18℃ lower than that of R22 and R410A, 6℃ lower than that of R407C. COP of NCUR01 is about 5% higher than that of R22, 19.6% higher than R410A, and 9.7% higher than R407C. Thus it is an excellent near-azeotropic refrigerant, a feasible alternative of R22.

Study on salt dissolution and salt effect is important for development of chemical technology. The solubility of terephthalic acid disodium in water at different temperatures was measured by using equilibrium method at atmospheric pressure. For seven organic salts and three inorganic salts, the dissolving process of two salts in water was examined under the normal pressure and 298.15 K. It is found that the feeding sequence affects the dissolution of two salts. When difficult ionized salt is dissolved first and easily ionized salt is dissolved later, the dissolution rate of the latter does not change obviously; when easily ionized salt is dissolved first, the dissolution rate of difficult ionized salt is significantly reduced and the solubility decreases. Fixing the amount of one salt, the amount of another salt dissolved in a period of time is defined as the quasi-solubility. The determination of quasi-solubility of terephthalic acid disodium in different concentrations of sodium citrate solution provides the basis for purification of chemical products.

The orthogonal wave type (OWT) tray, a new type of dual flow tray, was developed. A 3D transient computational fluid dynamics model in the Eulerian-Eulerian framework is developed to predict the hydrodynamics of OWT tray. Drag force is mainly considered as the interphase momentum exchange term and calculated using the Krishna correlation. Simulated clear liquid height is in good agreement with the experimental value. The hydrodynamics including pressure drop, liquid velocity and gas-liquid distribution under various gas and liquid rates are investigated. Comparison with sieve tray without downcomer shows that OWT tray has an improved turn down ratio and stability.

Two indicators were proposed to evaluate the performance of H-type finned tube, i.e. the heat exchange per unit mass and the recovered heat transfer per unit power of the fan, and a selection method was derived to determine the structure parameters for the H-type finned tube. Numerical studies were performed to investigate the H-type finned tube with different fin widths and pitches. The results show that with the increase of fin width, the heat transfer per unit mass of finned tube increases first and then deceases, and when this indicator reaches the maximum value with different fin pitches, the fin width is between 55 and 60 mm. With the increase of fin width, the recovered heat transfer per unit power of the fan also increases first and then deceases, but when this indicator reaches the maximum value with different fin pitches, the fin width increases gradually. The fin pitch has the minimum value when both indicators reach the maximum value, so the two indicators as well as the manufacturing process and fouling characteristics should be taken into consideration for selecting the structure parameters.

Considering fluid temperature-dependent viscosity, turbulent flow and heat transfer in the jackets with helical ducts were investigated numerically. Comparisons between experimental values and simulated values indicated that the simulation method was reliable. Based on the simulated results, the effects of temperature-dependent viscosity on the characteristics of turbulent flow and heat transfer were studied, variations of the mean flow resistance (fRe_m) and mean Nusselt number (Nu_m) of cross section in the flow direction were analyzed, and the whole flow resistance and the whole Nusselt number of varied viscosity flow were compared with those of constant viscosity flow. The results show that temperature-dependent viscosity affects the features of fluid flow and heat transfer in the jackets to a certain extent. The development of fRe_m and Nu_m along the axial direction is divided into the early, the middle and the later stages. The difference is obvious at the later developing stage between the trends with varied viscosity and constant viscosity. Under the same incoming flow and thermal boundary conditions, compared to those with constant viscosity, the local flow resistance with varied viscosity is lower, the local Nusselt number is larger, so that the whole flow resistance is lower and the whole Nusselt number is larger. Furthermore, with the decrease of the Reynolds number and the dimensionless curvature ratio, differences between the characteristics of flow and heat transfer for varied and constant viscosities are more obvious, so temperature-dependent viscosity is a greater contributing factor to fluid flow and heat transfer.

To establish coupling algorithm of radiation and conduction for one-dimensional translucent material with phase change, to understand the melting process of n-octadecane with infrared irradiation source, and to obtain the temperature distribution in the material, the modified equivalent heat capacity method is used for latent heat absorption and release with transient heat transfer, the gradient refractive index method is used for radiative transfer in variable refractive index medium, and a calculation method is established for phase change process of coupling radiation and conduction of one-dimensional semitransparent materials based on the reproducing kernel particle method (RKPM). The temperature response characteristics of n-octadecane with phase change were measured experimentally under the infrared radiation heating condition to verify the accuracy of numerical method. The results show that numerical simulation values match the experimental values well both in the temperature level and time characteristics, indicating that the method has very good accuracy. The selection of convective heat transfer coefficient has a certain influence on the simulation results.

The influencing factors for mass transfer of gas-liquid interface in liquid desiccant system are analyzed. A mass transfer correlation is given in dimensionless form based on the driving force of mass transfer, which is the vapor pressure difference through gas-liquid interface. The constants in the correlation are fitted based on published experimental data of LiCl-H₂O-air system in a column packed with cross corrugated cellulose. Another group of published experimental data of LiCl-H₂O-air system in a column packed with polyvinyl chloride is used for validating the correlation, with the relative deviation between experimental and calculated results from -10.48% to 5.28%. Moreover, a liquid dehumidification system driven by heat pump is set up, with LiBr-H₂O as desiccant and finned tube heat exchanger as packings, and the experimental data are used for validating the correlation. The result shows that the deviation is -1.8%-12.8%. All these results show that the correlation has a high accuracy for mass transfer coefficient prediction in liquid dehumidifier with structured packings.

Bubble size distribution influences the separation efficiency of dissolved air flotation (DAF) while it is mainly affected by the coalescence phenomenon. In this study, both experiments and numerical simulation are performed to study the bubble coalescence in the contact zone of a DAF tank. By comparing the simulation results with experimental measurement data, the numerical simulation method based on population balance model is established to investigate the bubble coalescence behavior in the contact zone (c-zone). Luo aggregation model, Free molecular aggregation model and Turbulent aggregation model are adopted to predict the bubble size distribution (BSD), respectively. The results indicate that Turbulent aggregation model reproduces the BSD accurately and is more suitable for bubble coalescence simulation in the c-zone. During the flotation process, the bubble coalescence mainly takes place at the lower part of the c-zone and the bubble diameter does not change at the upper part of the c-zone. Besides, the addition of bubbles enhances the diffusion of flow with eddy occurring at the upper part and horizontal flow from the wall to the center at the lower part of the c-zone.

Submerged combustion vaporizer (SCV) is widely used in LNG receiving terminals. In order to study the flow and heat-transfer characteristics of supercritical LNG in SCV coil tubes, a three-dimensional computation model is established to analyze the influence on fluid temperature and local heat transfer coefficient, base on pressure, heat flux, inlet velocity and variation of physical properties. The results indicate that the local heat transfer coefficient first increases and then decreases along the flow direction, and the maximum occurs at the pseudo-critical temperature. Due to the secondary flow, the coefficient of local heat transfer increases abruptly. In the range of operational pressure, the maximum of local heat transfer coefficient decreases with increasing tube-side pressure. As the heat flux increases, the maximum of local heat transfer coefficient increases and appears earlier, and drops faster after the maximum. Higher heat flux deteriorates the heat transfer. The maximum of local heat transfer coefficient increases and appears later as the inlet velocity increases. The numerical simulation study provides scientific guidance to the design of SCV.

A new type of heat pump driven household outdoor air processor using solid desiccant is proposed. Two stages of square solid desiccant plates are used for dehumidification. For each stage, two desiccant plates are placed in the processed air duct for dehumidification and in the regeneration air duct. Continuous dehumidification is realized by exchanging positions of the desiccant plates in the two air ducts. The cooling capacity and exhaust heat of the heat pump are utilized to cool the processed air and provide regenerative heat to the desiccant. Numerical models and experimental validations of the air processor are discussed. The influences of switching modes (mode 1: exchange positions simultaneously; mode 2: exchange positions alternatively), switching time interval, processed air inlet states, and stage number on the performance (COP) of air processor are numerically investigated. The results show that, the optimal time interval of mode 2 is half of that of mode 1. The optimal time intervals under mode 1 are 8 and 4 min, respectively, for air flow rates of 300 and 500 m³·h^-1. COP enhances with the increase of stage number. The cooler and drier the processed air inlet state, the higher the COP. Under the Beijing summer condition and the ARI summer condition, COPs are above 3.5 and 5.5, respectively.

For investigating condensation heat transfer characteristic inside flat tubes widely applied in air-cooled condenser in large power plant, a water cooled visualization condensation test system is designed and built for an indirect study on the flow regime of condensation process in a condenser. Base on the observed stratified flow regime, a theoretical model is built for condensation flow and heat transfer process including condensate water bath development on the arc wall and condensate film development on the other wall. Especially, for condensate film on the wall, a hyperbolic equation is proposed. Considering the convection and conservation characteristic in the equation, a solution algorithm for steady conservation equation is produced by combination of the conjugate gradient method, the Newton method and simulated annealing method, which can avoid the complex of traditional non-steady method. The visualization results indicate that the flow regime of condensation process is stratified flow regime and the corresponding theoretical calculation results indicate that the condensate film thickness on the wall is far less than condensate bath height, which is in the 1 mm order of magnitude, and leads to high condensation heat transfer coefficient. The results supply grounds for judging the onset position of freezing in flat tube under air cooling condition in power plant in winter.

This paper focuses on the relationship between bubble behavior and bumping of aging oil. A visualization boiling vessel is built and relevant mathematical model is established according to the generation, growth, departure and rising of single bubbles, recorded by a high-speed camera. Results show that, with the increase of driving force ΔT_s (degree of superheating), the water on the heat transfer surface boils, forming vapor-in-oil bubbles. The departure time of bubbles decreases with the increase of heat flux, while the density of nucleation sites on the heat transfer surface increases. As ΔT_s increases continuously, a bubble layer forms when the rupturing rate of bubble is lower than their producing rate. Accumulation of a large number of bubbles will make the bubble layer amplify to the entire container space rapidly to form bumping.

A new inlet of the gypsum hydrocyclone with separation block and guide plate was presented in this paper. The particle trajectories in conventional hydrocyclone and particle movements in new inlet were simulated by computational fluid dynamics (CFD) with the Reynolds stress model (RSM) and discrete phase model (DPM). The simulated results showed that both particle moving radius and distance increased when the particle diameter became greater. Gypsum particles with variable size were separated at the new type of inlet, which was beneficial to the classification performance of the hydrocyclone. Experiments were carried out in order to have further understanding of the new inlet. It was found that the classification efficiency of particles with the diameter between 10 and 30 μm was obviously improved about 15% compared to the conventional hydrocyclone. The classification efficiency of particles with the diameter less than 6 μm presented a certain drop. At the same time, the density of underflow slurry increased apparently.

An analytical heat transfer model was established for a borehole heat exchanger (BHE) with single U-tube in stratified soils based on the moving finite line heat source model, taking the factors such as soil stratifications and groundwater advection into account. This model was validated by the data obtained in an on-site soil thermal response test. The soil temperature responses to the BHE heat injection were obtained by using this model and homogeneous model. Comparison of these two sets of results indicates that the soil temperature around the BHE along axial direction is not uniformly distributed due to the characteristics of soil stratification. It takes different length of time for the borehole wall temperature to reach stable and to maintain at a different stable temperature in every layer, due to the difference of physical properties of soil in each layer. Three cases are calculated and analyzed for homogeneous soil, stratified soil with groundwater advection in whole soil domain, and stratified soil with groundwater advection in some soil layer. It shows that the heat transfer efficiency coefficient is underestimated up to 6.3% if ignoring the soil stratification and the influence of groundwater advection. The thermal effect distance deviation in each soil layer may be up to 43% for cases with and without groundwater advection. In order to assess the soil temperature distribution characteristics around the BHE with the influence of groundwater advection, it is suggested that the stratified soil model is applied to calculate the thermal effect distance in each soil layer and their maximum value is chosen as the borehole spacing. Otherwise, the borehole spacing may be too small for the design of multiple BHEs.

UV photocatalysis-assisted adsorptive desulfurization of bi-functional Ti-Si-O materials was investigated for clean gasoline. The Ti-Si-O materials were prepared by the sol-gel method and then characterized by N₂ adsorption, X-ray diffraction, etc. Desulfurization performances of the Ti-Si-O materials were examined. Sulfur species in gasoline were measured by HPLC, coulomb instrument, GC-MS and GC-SCD. The results showed that at the Ti/Si mole ratio of 3:7, the desulfurization efficiency of the Ti-Si-O material reached the maximum [96%, 11.52 mg S·(g sorb)^-1], which was more superior than those of the pure TiO₂ and SiO₂ materials. The photocatalysis-assisted adsorptive desulfurization (PADS) rates of Ti_0.3Si_0.7O₂ for the three organosulfur compounds followed the order of T > MT > BT. On the basis of GC-MS analysis for desulfurized products, it could be judged that the organosulfur compounds in gasoline were firstly photocatalytically oxidized to polar sulfone over Ti_0.3Si_0.7O₂, and then selectively adsorbed on Ti_0.3Si_0.7O₂. Ti_0.3Si_0.7O₂ can be efficiently regenerated by acetone washing and then hot air oxidation. The regenerated Ti_0.3Si_0.7O₂ exhibited very good activity of oxidation and adsorption after five cycles of oxidation/adsorption and regeneration, and with this PADS technology, the real gasoline can be desulfurized to < 10 mm·g^-1 by using Ti_0.3Si_0.7O₂.

The adsorption kinetics of diesel oil by multi-walled carbon nanotubes (MWCNTs) was investigated using static adsorption experiment and compared with activated carbon. The results show that the adsorption quantities on both the MWCNTs and activated carbon increase fast in the first 10 min, and the adsorption equilibrium can be reached in about 60 min, while the adsorption capacity on MWCNTs is far higher than activated carbon. The kinetic analysis shows that the adsorption kinetics can be accurately represented by a pseudo second-order model. The activation energy (E_a) of 14.21 kJ·mol^-1, determined by the Arrhenius law, suggests that physisorption dominates the adsorption of diesel oil 2^# onto MWCNTs. The analyzing results with intraparticle diffusion model show that the adsorption mechanism is complex for MWCNTs, consisting of external surface adsorption, internal diffusion in large interstitial pores and in small interstitial pores between the tubes, while for activated carbon it consists of external surface and intraparticle diffusion stages and is strongly influenced by the boundary layer. Initial adsorption behavior is found in the adsorption process of diesel oil onto MWCNTs. The adsorption of three diesel oils at constant temperature (298 K) and that of diesel oil 2^# at different temperatures (288, 298 and 308 K) show intermediately initial adsorption behavior. For diesel oil 2^#, with the increase of temperature, the initial adsorption enhances, and at 318 K, intensive initial adsorption occurs.

Activated carbon fiber (ACF) was used for the adsorption of phenol in petrochemical wastewater. Adsorption isotherms at 25, 40, 55 and 65℃ were determined and fitted with Langmuir, Freundlich and Redlich-Peterson equations. The results show that the adsorption equilibrium data fit Langmuir and Redlich- Peterson equations better than the Freundlich equation. The phenol adsorption ability of ACF from simulated wastewater decreases with the increase of temperature, while the situation is somewhat different with petrochemical wastewater. The adsorption kinetic data fit the pseudo-second-order kinetic model well in petrochemical wastewater and simulated wastewater. The intra-particle diffusion is the main rate-controlling step in the initial period and k_id of phenol adsorption increases with temperature in petrochemical wastewater. The adsorption rate is influenced by intra-particle diffusion and external diffusion in the middle and later period. Thermodynamic analysis shows that the ΔG value is negative, indicating that the adsorption of phenol in petrochemical wastewater by ACF is spontaneous. However, ΔG does not change obviously with temperature owing to the influence of oil on phenol adsorption in petrochemical wastewater.

For the demerits of fruit fly optimization algorithm(FOA), such as easily falling into local optimum, slow convergence rate and low convergence precision, an improved FOA is proposed called multi-strategy fruit fly optimization algorithm. It is based on social cognitive part of particle swarm optimization algorithm (PSO) and the differential vector of differential evolution (DE). For those individuals whose smell concentration values are worse than the average concentration, using social cognition operator generates next generation to accelerate the convergence rate. For others, introducing the differential vector improves the ability to jump out the local optimum. Through the simulation on eight benchmarks and comparison with other algorithms, the experimental results show that SFOA has better global search capability, fast convergence and higher convergence precision. Finally the SFOA is also applied to optimize the operation of a GE gasification process, which is to maximize the syngas yield with two decision variables, i.e., oxygen-coal ratio and coal concentration. The results show that SFOA can quickly find the optimal value, which demonstrates the effectiveness of SFOA.

Independent component analysis (ICA) method is mainly used to monitor linear and non-Gaussian process, a method named modified independent analysis (MICA) is proposed to improve the non-Gaussian process monitoring performance. The method uses the information of process data to modify the monitoring process monitoring performance. The method uses the information of process data to modify the monitoring index of ICA. Many industrial process variables have characteristics of nonlinear, non-Gaussian and Gaussian mixture distribution. A method which based on LTSA algorithm and the combined index is proposed to solve these problems of the industrial process. Firstly, the local tangent space alignment (LTSA) algorithm is used to achieve the nonlinear dimensionality reduction of sample data. Then MICA and PCA methods are used to obtain non-Gaussian and Gaussian statistics, and the new statistic, which is weighted by these two statistics, is used for process monitoring. Finally, the proposed method has been applied to monitor the Tennessee-Eastman(TE) process and the ethylene cracking furnace to show its efficiency.

Acetylene hydrogenation reactor is an important device of the ethylene plant, and its working condition directly affects the purity and yield of ethylene products, so it is of great significance to improve the modeling and optimization efficiency of the reaction process for acetylene hydrogenation. However, directly optimizing high precision CFD models are often low efficiency because of the large calculation. This paper from the model accuracy of prediction variance and improvement of the effectiveness of global search, proposes a bootstrap GEI algorithm based on Kriging surrogate model. Through simulation contrast of test functions, compared with bootstrap EI algorithm, this algorithm can find the optimal sample points of global search and reduce the number of sample points, so as to improve the efficiency of the model updating and optimization. And this algorithm is effectively validated in the surrogate model of acetylene hydrogenation reactor.

As a collection of multiple/various production enterprises, an industrial park is able to produce more opportunities for the cooperative utilization of resources. In this context, specific resource allocation strategies are desired for parks because of their characteristics that different from a single plant. To solve the water allocation problem of parks and also consider the practical production requirements, this study presents a synthesis method considering intra-plant pre-treatment operation in individual plant, which means the inter-plant and intra-plant regenerators are both set and selected during synthesis. The superstructure and the mathematical model are thus established and formulated with the target of minimum fresh water consumption. Finally, an example is illustrated to demonstrate the capability of the method.

With an increasing shortage of water resources, more rigid regulations regarding waste water discharge, water saving and discharge reduction have become more and more valued by industries. However, the traditional water utilization networks only regard impurity concentration as the restricting factor for controlling material reuse and overlook the effect of stream's characteristic or function on its reuse, thus unable to reflect the actual industrial production requirement. Therefore, it is of great significance to look into the multiple-property integration of water utilization networks. In this paper, a method is proposed where the super structure model of multiple-property water utilization considering the environment problems is presented as a basis, on which a process is added to reuse part of streams in the treated water stream characteristic process for the sinks. This method takes the minimum annual cost as the target function and builds the mixed integer non-linear programming mathematical model with the consideration of environment, the direct reuse of stream in the process and reuse of stream from treated water. The model is then evaluated, whose result reveals that this method reduces not only the annual total cost but also the use of fresh water and waste water discharge, validating the efficacy and superiority of the proposed method.

In order to find out root alarms so as to avoid alarm flooding in industrial processes, this paper suggests a fuzzy weighted association rules mining method which integrates fuzzy sets, the Apriori mining algorithm and time-series analysis to extract the association rules from alarm sequence data. Considering the temporal characteristics and similarity attributes of the alarm data, the similarity degrees are assigned as the weights of the association rules, enhancing the algorithmic efficiency and accuracy. Further, in contrast to quantitative knowledge representations, the resultant fuzzy association rules are easier identified to the operators. Practical data of an industrial process are employed to illustrate the benefits of the proposed method.

Coal to synthetic natural gas (SNG) process is regarded as one of promising way to tackle with haze in north China and is developed rapidly in China. However, coal to SNG processes suffer from the high energy consumption and CO₂ emission due to the high carbon contents of coal. In China, there is 7×10¹⁰ m³ coke-oven gas (COG) produced in coke plants annually. Most of the hydrogen-rich COG is utilized as fuel or discharged directly into the air. Such situation is a waste of precious hydrogen resource and causes serious economic loss and environmental pollution either. The co-feed process of coal and COG to SNG is a promising solution for these problems. In the co-feed process, CH₄ of COG reacts with CO₂ in a dry methane reforming unit to reduce emissions and H₂ of COG can adjust the H/C ratio of syngas. This paper makes a modeling, simulation and system analysis for the co-feed process of coal and COG to SNG. The results show that the energy efficiency of the co-feed process increases by 8%, while at the same time, CO₂ emission is reduced by 60% in comparison to the conventional coal to SNG process.

A recently developed method for reducing reaction mechanism, the reaction-diffusion manifolds (REDIM) method, is combined with the presumed filtered density function (PFDF) to construct a new sub-grid scale (SGS) combustion model for large eddy simulation (LES) of turbulent combustion. Unlike its predecessor intrinsic low-dimensional manifolds method, the REDIM method takes into account the coupling of reaction and molecular transport processes explicitly, so it is capable of describing fast reaction regions as well as regions where chemical kinetics are slow and diffusion governs the overall process. Because of this advantage of REDIM, the new SGS combustion model is theoretically capable of simulating turbulent partially premixed flames and stratified flames, in which reaction and diffusion processes are both important. For validating its performance, the new model is employed to simulate the benchmark Darmstadt turbulent stratified flame (TSF). First, a grid resolution study is conducted by computing isothermal flow field with two grids. Then the finer grid is used to simulate a turbulent flame with stratified effect. The overall good agreement of the statistics of velocity, temperature and species with the experimental data demonstrates the capability of the LES method and the REDIM-PFDF model for dealing with TSF. More simulations for other Darmstadt TSF cases are still ongoing, to obtain a deeper insight of the complex chemistry-physical process in the TSF combustion.

Due to waste oil can cause serious pollution and various social problems, a study of its comprehensive utilization is imperative. In this study, soybean oil was used as substitute of waste oil and converted into syngas in a homemade rotating arc plasma reactor. Effects of water/oil mass ratio, input power and magnetic flux intensity on reaction performance were investigated. It was shown that the main product gas was CO and H₂, accounted for more than 91.0% (vol), as well as small amounts of CO₂ and hydrocarbons. Water/soybean oil mass ratio has a large impact on syngas compositions and energy conversion efficiency, but little impact on carbon conversion and syngas yield. Carbon conversion increased to 98.5% with the increase of input power and energy conversion efficiency reached the maximum of 72.9% at 17.9 kW. Magnetic flux intensity has a slight effect on results but it could protect the anode from erosion.

Accumulation of static electricity is one of the most serious potential hazard factors for transport and storage of flammable insulating fluids. The electrostatic accumulations rate of fluid flow by friction against solid walls is the key issue to reveal the essential characteristics of accumulation process. A rotating disk system was designed and fabricated for simulating the electrification and measuring the instantaneous electric charge of several common insulating fluids such as transformer oil. How the velocity, temperature and viscosity of the fluid contribute to the electrification rate was experimentally investigated under different conditions for these fluids. It is found that the electrification rate is substantially proportional to the linear velocity of fluid flow. Its relationship with temperature is complicated, showing the existence of a minimum electrification rate in a certain range of temperature. And the qualitative behavior that stronger insulating fluid has greater electrification rate has been verified quantitatively.

Three column sequencing batch reactors (SBR) (R1, R2 and R3) were operated under various aeration intensity of 0.5, 1.0 and 1.5 L·min^-1, respectively. The influence of aeration intensity on characteristics, treatment performance and biomass of the phosphorus removal granules (PRGs) were investigated. PRGs were formed in all reactors in 30 days and operated steadily for another 30 days. The results showed that the aeration intensity had an important impact on the settling ability, particle size, morphology, moisture content, treatment performance and biomass. With the increase of aeration intensity, the diameter and settling velocity of matured granules were increased, which were 900 μm and 24-144 m·h^-1, 1000 μm and 29-162 m·h^-1, and 1150 μm and 33-178 m·h^-1 in R1, R2 and R3, respectively, while the moisture contents were decreased and were 95.6%, 94.2% and 93.4%, respectively. Therefore, compared with the low aeration intensity, the PRGs under the higher aeration intensity had better physical characteristics, settling ability and treatment performance due to the more biomass and denser structure. PRGs under higher aeration intensity were spherical or elliptic and had regular contours, but the structure and shape of PRGs under lower aeration intensity was loosened and irregular. Meanwhile, the MLVSS/MLSS, biomass layer thickness of PRGs and P release/COD uptake ratios in all reactors at the 51th day were calculated. MLVSS/MLSS and biomass layer thickness of granules in R1, R2 and R3 were 78% and 0.34 mm, 82% and 0.35 mm, and 86% and 0.38 mm, respectively. It demonstrated that granules in the reactor with higher aeration intensity had a relatively thicker biomass layer and more biomass. The P release/COD uptake ratios in R1, R2 and R3 were 0.35, 0.35 and 0.36, respectively, indicating that the content of phosphorus accumulating organisms (PAOs) was high in all reactors of this research.

The refrigerant charging quantity has significant effect on the performance of a refrigeration system. For a specific mixed refrigerant (MR) Joule-Thomson cooler, proper MR charging quantity is determined by operation pressure, temperature and concentration of components. It is difficult to determine the optimal MR charging quantity by means of experimental test, so a MR mass charge prediction model is established in this paper. Using the integral method, the Linde-Hampson cooler is divided into four parts to calculate the MR mass distribution and the liquid hold-up. The calculation result shows that, over 60% of the MR is accumulated in the hot steam of the recuperative heat exchanger, the liquid MR occupies more than 80% of the total charging quantity, and the mass of liquid MR will increase as the refrigerating temperature decreases. An experimental investigation is used to verify the accuracy of this model. The result shows that, in the refrigeration temperature of -100-60℃, the deviation between the calculated MR charging quantity and actual one is not more than 20%. The deviation between the calculated proportion of components and the experimental result is also less than 20%.

In order to reduce the refrigerant charging quantity while maintaining the performance of an air conditioner, the refrigerant hold-up in the condenser of a domestic air conditioner is experimentally studied. The results indicate that more than 60% of the total refrigerant charging quantity is in the condenser, since the liquid-phase hold-up in the two-phase and subcooled regions is relatively large. Therefore, a finned tube falling film condenser is proposed and employed since vertical tubes can decrease the refrigerant hold-up. Consequently, the total refrigerant charging quantity is reduced from 1050 g to 550 g while the system performance maintains stable.

The emission of nitrogen-containing compound from a heavy-duty diesel engine with selective catalytic reduction (SCR) was studied by using Fourier transform infrared spectrum (FTIR) technology. The main emitted nitrogen-containing compounds including NO, NO₂ and N₂O under different operating conditions were analyzed. The results showed that the NO emission from the engine without SCR ascended with increasing engine load. The NO₂ emission ascended firstly and then declined, while the N₂O emission was very low. Compared to the engine without SCR, the NO and NO₂ emissions from the engine with SCR significantly descend, and the NO₂ emission decreased remarkably at rated engine speed, which was because the rapid SCR reaction rate increased with increasing NO₂/NO ratio. The N₂O emission from the engine with SCR was more than twice from the engine without SCR, particularly higher at full load, which was due to the existed SCR side reaction. The N₂O emission ascended with increasing engine load since that increasing exhaust temperature led to higher oxidation reaction rate of NH₃ to N₂O. The NO/NO_x ratio of the engine with SCR was obviously lower than that of the engine without SCR, while the NO₂/NO_x ratio and N₂O/NO_x ratio were 12.8% and 20.7%, respectively, which were much higher than those of the engine without SCR.

To efficiently recover the waste heat from the diesel engine exhaust, an organic Rankine cycle (ORC) system was employed. The variation tendency of the diesel engine exhaust energy under various operating conditions was analyzed through experiments. Based on the particle swarm optimization, the operating parameters including evaporation pressure, superheat degree, and expansion ratio of ORC systems were optimized with net power output and exergy efficiency selected as objective functions. The optimization results show that, for a certain operating condition of the diesel engine, the optimal values for evaporating pressure, superheat degree, and expansion ratio can be determined. According to the optimization, the ORC system and vehicle diesel engine-ORC combined system are studied. The results show that, at the diesel engine speed of 2200 r·min^-1 and engine torque of 1215 N·m, the net power output of the ORC system is 30.61 kW and the power output increasing rate of the combined system is 9.86%. At the diesel engine speed of 1200 r·min^-1 and engine torque of 1131 N·m, the brake specific fuel consumption of combined system is 175.0 g·(kW·h)^-1.

The high cost of magnesium is one of the key problems for the practical application of struvite chemical precipitation. Ammonium in wastewater was recycled by changing the initial conditions of struvite precipitation with cheap magnesia. The results showed that when the initial pH was 2, the removal rate of ammonium was above 90% by struvite precipitation technology with cheap magnesia as magnesium, which was above 82% at the conditions of the mole ratio of Mg²⁺:NH₄⁺:PO₄^3-, 1:1:1 and calcination temperature of magnesia of 200-400℃. The XRD and FTIR results also showed that the crystal structure of magnesia was distorted with changed bond length of Mg O at different calcination temperature, leading to redshift and blueshift. A direct correlation was found between Mg O bond length and ammonium removal ratio.

In order to achieve nitritation/anammox in sewage treatment, the feasibility of achieving partial nitritation using free nitrous acid (FNA) to treat activated sludge was studied in a system treating real wastewater. The results showed that the FNA inhibition on NOB was stronger than that on AOB since the decrease of nitrite oxidation rate was more than that of ammonium oxidation rate, after treating activated sludge by FNA. At the same time, FNA inhibition incresed with increasing FNA concentration at 0-0.75 mg HNO₂-N·L^-1. The nitrite accumulation rate (NAR) was only 1% after seeding activated sludge obtained from a wastwater treatment plant, indicating that nitrification was happened. When FNA treatment was used with a sludge retention time (SRT) of 15 days, nitritation was achieved since NAR increased to above 90%. The partial nitritation was achieved, and the ratio of of NO₂^--N/NH₄⁺-N effluent was 1.24 on average when hydraulic retention time (HRT) decreased to 2.5 h. This effluent could meet the requirement of anammox reaction. Thus, partial nitritation could be achieved in sewage treatment system using the activated sludge treated by FNA when SRT and HRT were controlled.

Constant current spouted bed particle electro-deposition method had been studied with simulated wastewater containing copper and nickel as the research object under different experimental conditions such as pH, current, temperature with N₂. experimental results showed that under the experiment conditions of pH 3 (first 210 min) and 4.5 (next 270 min), electrolyte concentration 1 g·L^-1, constant current 15 A, cathode particle size 1.8 mm, electrolyte temperature 25℃ with blowing N₂, the largest removal rate of Cu²⁺ was 99.88% and Ni²⁺ was 85.21% after 480 min. During the experiments, DO first rapid increased to the maximum, and then came down slowly. Blowing N₂ into electrolyte could significantly reduce the dissolved oxygen concentration, which could effectively inhibit deposited Cu and Ni once again return to dissolve and improve the removal rate of deposited metals. The replacement reaction between Ni and Cu²⁺ weakened, the corrosion rate of deposited copper while it was intensified for nickel. Thus, the electro-deposition of mixed copper and nickel showed a certain order, which suggested that the separate recycling of metals in wastewater was feasible with the spouted bed particle electro-deposition method under certain conditions.

Arsenic volatilization characteristics of SJS bituminous coal were carried out on the high-temperature tube furnace from 600℃ to 1400℃ at different oxy-fuel atmospheres. Combined with FTIR analysis and thermodynamic analysis, and taking air condition into consideration, the effects of O₂, CO₂ and temperature on arsenic volatilization were studied. Results showed that the releasing proportion of arsenic increased with increasing temperature both in oxy-fuel and air combustion. Two arsenic mass loss peaks were observed at ＜900℃ and > 900℃ stages, separately. At temperature lower than 900℃ oxygen content was the major fact. The more O₂ ratio, the larger volatile proportion of arsenic. But at the same O₂ ratio condition, the higher CO₂ concentration brought down the emission of arsenic and thus the volatile proportion was decreased. At temperature higher than 900℃ the content of carbon dioxide was the major fact, The higher CO₂ concentration in oxy-fuel atmosphere hindered heat transfer, and thus higher temperature was needed for the decomposition of arsenates under the same conditions, which led to the delay of the intensive emission of arsenic compared to air condition. Besides, high CO₂ content in oxy-fuel condition resulted in the reductive atmosphere around coal particles, which caused arsenic compounds with high chemical valence being reduced to compounds with lower chemical valence, while the arsenic compounds with lower chemical valence were unstable and their fast decomposition led to the higher mass loss rate of arsenic in oxy-fuel condition than to the air condition.

Ni(OH)₂ sample is prepared by chemical precipitation method with Ni(NO₃)₂·6H₂O and NaOH as raw materials. X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) analysis reveal that the sample is β-Ni(OH)₂ with sheet-like hierarchical nanostructure. Cyclic voltammograms (CV) and charge-discharge tests are performed to study the lithium ion storage performance of the β-Ni(OH)₂ sample. The results show that the prepared β-Ni(OH)₂ sample has a very high lithium ion storage activity. For example, at a charge-discharge current density of 50 mA·g^-1, the discharge capacity of the third cycle for the prepared β-Ni(OH)₂ is higher than 1550 mA·h·g^-1. The carbon content in electrode has a great influence on both the cyclic stability and rate performance of the β-Ni(OH)₂ sample. The mechanism of carbon content on lithium storage performance of the β-Ni(OH)₂ sample is analyzed by electrochemical impedance spectroscopy (EIS) tests.

In the present study, the anaerobic contact reactor (ACR) was used to produce hydrogen from diluted molasses by anaerobic fermentation, and an ethanol-type fermentation and butyric-type fermentation were established by keeping the effluent pH of the two reactors at 4.5-5.0 and 5.5-6.0, respectively. And then the comparison of the impact of influent substrate concentration on the performance of the above two reactors was investigated. For the ethanol-type fermentation system, the fermentative hydrogen-producing efficiency was enhanced when the influent chemical oxygen demanding (COD) was increased from 5000 to 12000 mg·L^-1 under the HRT of 6 h, whereas, the feedback inhibition was turn to be functioned as the influent COD was increased to 15000 mg·L^-1. It was found that the hydrogen production rate (HPR), specific hydrogen rate of sludge (SHPR) and hydrogen yield (HY) was peaked at 68.8 L·d^-1, 744.5 ml H₂·(g VSS·d)^-1 and 2.3 mol H₂·(mol glucose)^-1, respectively, when the influent COD was 12000 mg·L^-1. For the butyric-type fermentation system, the hydrogen producing efficiency was decreased on the whole as the influent COD was increased from 5000 to 20000 mg·L^-1 under the HRT of 8 h. It also showed that the maximum value of SHPR and HY was 159.6 ml H₂·(g VSS·d)^-1 and 1.0 mol H₂·(mol glucose)^-1, respectively, when the influent COD was 5000 mg·L^-1. It indicated that the hydrogen-producting capability of ethanol-type fermentation was better than that of butyric-type fermentation.

Formamide (FA) as modifier, a novel sodium acetate trihydrate (SAT)/formamide (FM) composite phase change material (CPCM) was prepared by melt blending method. The influence of the formamide mass fraction (the same as below) on the phase change enthalpy and the temperature of SAT/FA mixture (matrix) was discussed. The effects of nucleating agent and thickening agent on the phase separation, the degree of supercooling and the release time of composite material were systematically investigated by melting-solidification cycle and step cooling curve. The structure and performance of novel CPCM were characterized by FTIR, XRD and DSC. The results showed that the SAT/FA eutectic mixture formed by adding 25% formamide into SAT. The SAT/FA CPCM formed by adding 2% disodium hydrogen phosphate dodecahydrate (DSP) as the nuclear agent and 2% polyvinyl alcohol (PVA) as thickening agent, had a low degree of supercooling (2.67℃), long heat release time (10170 s) and excellent cycling stability. Its phase change enthalpy and temperature were 233.9 kJ·kg^-1 and 40.88℃, respectively, indicating that it can be applied to floor radiant heating with phase change thermal storage.

With the waste polypropylene (WPP) as matrix and the modificated non-metallic powder from waste printed circuit boards (NWPCB) as filler, the WPP/NWPCB composites were prepared by means of the melt blending. To enhance the mechanical characters, the WPP/NWPCB composites were synergistically modified by ethylene octene copolymer (POE) and maleic anhydride grafted polypropylene (PP-g-MAH). The mechanical properties and morphology analysis showed that POE greatly improved the impact strength of WPP/NWPCB composite materials. When the content of POE was 15 g·(100 g)^-1, the impact strength of WPP/NWPCB composites was increased by 129%. The interface bonding strength between filler and matrix was improved with modification by 9 g·(100 g)^-1 PP-g-MAH. The impact strength, tensile strength and flexural strength were increased by 7.8%, 23.4% and 20% respectively. The pyrolysis characteristics of WPP/NWPCB/POE composite materials were investigated by means of TGA-FTIR at nitrogen atmosphere. It indicated that the heat stability of WPP material in the composites was improved by the addition of NWPCB. The alkanes, olefins and CO₂ were released during the pyrolysis process of WPP/NWPCB composites, whereas a small amount of harmful gas such as phenol aromatic compounds and hydrogen bromide was also produced.

Three kinds of superfine sodium bicarbonate explosion suppression powder were prepared from commercial BC dry powder with different process and surface modification. Scanning electron microscopy and laser particle analyzer were used to investigate the surface properties and particle size distributions. Preliminary suppression experiments on methane-air mixture explosion at chemical equivalent ratio were carried out with the prepared superfine sodium bicarbonate powder in 200 L chamber. The key physical parameters of the suppression powder such as particle size and distribution, surface area, and surface properties are improved significantly with two of the preparation processes. For the designed explosion suppressor with optimized parameters, the total spray time of the suppression powder is in the range of 12 ms and the maximum jet velocity can reach 5-15 m·s^-1 at the opening pressure of diaphragm of 8 MPa. The efficiency of explosion suppression is not only related to the average particle size, the particle size distribution is also important, and powder with irregular surface shape can suppress the explosion more effectively. Compared to the normally commercially available BC powder, the ability of explosion suppression is improved eight to ten times when the powder is refined to the order of magnitude of ten micrometers.

An emulsion matrix was mixed with 0%, 2%, 4%, 6% and 8% by the mass of KCl separately, and then expanded perlite and chemical foaming agent as sensitizing agent were used separately to make two groups of emulsion explosives. Their explosion shock waves were tested in water before and after compression by shock waves produced by the host charge underwater. The pressure desensitization degrees of these emulsion explosives were calculated with the peak pressure values of tested shock waves and compared, and the influence of KCl content was analyzed. Results show that when KCl content is between 0% and 2%, the pressure desensitization degrees of the emulsion explosives are unchanged; when KCl content is between 2% and 8%, KCl content shows strong influence, desensitization degree increases with the KCl content. It means that the anti-pressing performance of explosives is worse with the increase of KCl content, the change of the quality and crystallization point of dispersed phase is a factor to change the pressure desensitization degree. These results can provide reference for coal mine blasting and further study on mechanism of pressure desensitization.