In order to investigate the effects of hydrolysis degrees of 3-mercaptopropyltriethoxysilane (MPTS) on the grafting mechanisms of nano-silica, the grafting activities and grafting mechanisms of the hydrolyzed products in different degrees are systematically investigated based on density functional theory (DFT). The results show that the cluster model of nano-silica optimized by the GGA-PBE function is the most reasonable. The O atoms in surface silanols of nano-silica are the nucleophilic sites and the H atoms are the electrophilic sites. For MPTS and its hydrolyzed products, the O atoms are the nucleophilic sites and the Si atoms are the electrophilic sites. The LUMO orbitals shift to Si atoms and the HOMO orbitals to O atoms after hydrolysis. The electrophilic indexes of Si atoms and nucleophilic indexes of O atoms are all increased according to the Fukui function, indicating that the hydrolyzed products are more susceptible to be attacked by the surface silanols of nano-silica and the activities of grafting reaction are improved after hydrolysis. The active energies (E _a) of grafting reactions for M0—M3 follow the order of M0＞M3＞M1＞M2 (M0 is short for MPTS, M1, M2, M3 are short for the hydrolyzed products of first, second, and third order, respectively), the active energies are obviously reduced after hydrolysis. The grafting reactions of M0-M3 are S_N2 nucleophilic substitution and exothermal reactions, but the mechanisms of the grafting reactions are quite different. For M0 — M2 the grafting reactions occur via the reaction channels of eliminating ethanol, but for M3 the grafting reaction occurs via the reaction channels of eliminating H₂O. The steric hindrance and the electrophilicity of Si atoms have a significant effect on the grafting reactions of M0—M2.

To promote the hydrate formation, surfactants Tween 80 and Span 80 are added as emulsifiers in HCFC-141b, organic phase change materials (n-decanoic acid and dodecyl alcohol) and water system. Organic phase change material-surfactant-refrigerant aqueous emulsion is prepared by high-speed stirring. Emulsion increases the contact area of water and HCFC–141b. The effects of organic phase change materials and surfactants on the formation of hydrates are investigated experimentally under static conditions. The results show that emulsifier can effectively increase the cold storage capacity of hydrate, reduce the induction time of hydrate formation, and reduce the randomness of hydrate formation. The lower the temperature of emulsion systems, the better hydrate promotion effect. The hydrate formation/decomposition cycle experiments show that the emulsion system with Tween 80 has good stability, and the organic phase change emulsion improves the stability during the hydrate formation/decomposition cycle.

Gas-solid bubbling fluidized beds have various industrial applications. The particles involved in practical applications usually display polydisperse characteristics (having different diameter or densities), resulting in segregation phenomena and consequently influencing flow hydrodynamics and reaction performance. Particle separation and mixing are inseparable from bubble motion, where interphase drag plays a key role. Recently, Ahmad et al. proposed a bubble-based mesoscale drag considering the effect of bidisperse features which is able to predict the bed expansion of binary bubbling fluidized beds. In this study, in order to investigate the applicability of the new drag model, two bubbling fluidized beds with different binary particle mixtures are simulated using the combination of the new drag model and the continuum model. Then, the bubble motion and axial profiles of jetsam volume ratio under two different fluidization states are mainly analyzed. It is found that the new drag model can predict well the particle segregation and mixing behaviors when the binary particles are fluidized completely. However, when the binary particles are fluidized at the transition state, the new drag model shows poor predictions, and the solid-solid drag plays a notable role in improving the prediction.

In the traditional fly ash aluminizing process, the acid immersion stirring tank adopts a rigid stirring paddle. Due to the limited pumping capacity of rigid impellers, some problems such as settlement of solid particles, deficiently of chaotic, and low efficiency of mixing in this process often occur in solid-liquid mixing processes. Thus, the rigid-flexible impeller was adopted to enhance solid-liquid chaotic mixing behavior in acid leaching process. In a fly ash-water system with a solids concentration of 30%, the chaotic mixing characteristics and energy dissipation were investigated in STRs equipped with rigid-flexible impeller. Torque sensor was employed to collect the torque time series signal. The largest Lyapunov exponents and the multi-scale entropy were compiled and calculated by Matlab to indicate the degree of chaotic mixing based on the torque time series signal. Meanwhile, the power consumption per unit volume was used to characterize the stirred reactor power characteristics. The effects of impeller types, rotation speed, flexible piece width/length, and impeller off-bottom clearance on chaotic mixing behavior were taken into consideration in the solid-liquid mixing processes. The results showed that the rigid-flexible impeller could effectively promote the chaotic mixing and reduce the accumulation of solid particles at the bottom of STRs in the fly ash-water system. Largest Lyapunov exponents of the system reached the maximum value of 0.0645 and multi-scale entropy was bigger than that of other conditions at the rotation speed of 120 r/min, the off-bottom clearance of T/4, the flexible piece length of 1.2H ₁ and width of D/8. The power consumption increases exponentially with the increase of rotation speed.

The computation load for traditional computational fluid dynamics-discrete element method (CFD-DEM) simulations tremendously increases when the number of particles augments in the system. The coarse-grained CFD-DEM method, in which a number of real particles are lumped into a numerical parcel, can remarkably reduce the computation load. It is necessary to extensively verify the coarse-grained CFD-DEM method before it is applied. Therefore, in the current work, the coarse-grained CFD-DEM method is validated in fluidized beds with various fluidization regimes. On one hand, it is found that gas and solid features (i.e., void fraction, pressure signals, and particle velocity) obtained from this method match well with the experiment measurements. On the other hand, as the coarse-grained ratios increase, the calculation time for a specific case is significantly reduced. In summary, the coarse-grained CFD-DEM contributes a great improvement of calculation efficiency while a little loss of numerical accuracy, which is expected to be a powerful tool to simulate gas-solid flow dynamics in large-scale dense particulate systems.

To maintain the performance of the power battery and prolong its service life, the temperature and temperature difference during the operation of the battery module should be maintained within an appropriate range. Thus, a new type of honeycomb liquid-cooled power battery module is proposed. The structure has an inlet/outlet guide plate inside and the battery is honeycomb-like distribution. The cooling liquid contacts with the battery indirectly at 360°, which greatly strengthens the heat transfer effect. On the basis of the numerical simulation and experimental validation of the thermal characteristics of single battery, a new model of honeycomb liquid-cooled battery module was established by computational fluid dynamics(CFD) platform, the thermal behavior of the battery module was studied, and the effects of the coolant flow rate, the coolant temperature of battery on the heat dissipation performance of the battery module were studied. The results show that: (1) Increasing the flow rate of coolant can significantly reduce the maximum temperature of the battery module and improve the temperature uniformity, when the flow rate of coolant increases to 1.5 L/min, the maximum temperature and the maximum temperature difference of the battery module tend to be stable; (2) Decreasing the temperature of coolant can significantly reduce the highest temperature of the battery module, but to a certain extent, the temperature uniformity in the battery module is deteriorated; (3) The coolant flow rate and the coolant temperature have significant influence on the heating characteristics of the battery module. Therefore, liquid cooling is necessary.

Under the condition of the same efficiency of other parts of organic Rankine cycle (ORC) system, the greater the heat exchange capacity of the evaporator, the smaller the irreversible loss, and the greater the potential of the system. Because of the phase transition temperature glide of mixture has good “matching” with the temperature change of heat source, this paper uses mixture as working fluid, and uses entransy flow dissipation rate to represent the irreversible loss of heat transfer process between mixture and heat source fluid. Combining T-Q diagram, the heat transfer process of mixture and heat source fluid in evaporator is analyzed. It is found that the area enclosed by the heat transfer curves of mixture and heat source fluid is the entransy flow dissipation rate, and the conditions of maximum heat transfer quantity and minimum irreversible loss of evaporator are obtained respectively, to guide the selecting of the optimal mixture and operation condition. According to the determined heat source, under the condition of maximum heat transfer quantity, a method for selecting the optimal mixture and optimal operating condition of the system based on the performance of evaporator is established. Adopting the heat source listed in reference paper, the optimum mixture and optimum outlet temperature are R600a/R134a(0.2/0.8) and 365.75 K, respectively. The heat transfer quantity of the evaporator is 3.3 times, under the condition that the parameters of other parts of the system are the same, the net output power of the system is 2.4 times than the optimum mixture in the literature.

With the increase of oil exploitation, the transportation of heavy oil with higher viscosity has received more and more attention. Based on the self-designed two-phase flow water annular transport heavy oil experimental system, the water annular transport heavy oil experiment was simulated and carried out. The flow pattern of the water annular generator under different gaps is captured, and the drag reduction effect of heavy oil transportation by water annular under different experimental conditions was analyzed. The experimental and simulated results show that the pressure drop in pipeline transportation can be greatly reduced by water annular conveying, and the water annular generator has the best drag reduction effect when the gap size is 0.9—1.4 mm. The pressure drop per unit pipeline will increase with flow rate, and high flow rate will reduce the drag reduction effect of water annular transportation.

In the process of wet-process phosphoric acid leaching, the mode of action of the traditional rigid stirring paddle is mainly shearing, and it is easy to form a symmetrical flow field structure and reduce the stirring efficiency. The effects of impeller type, impeller off-bottom clearance, stirring speed, length of flexible wire, diameter of flexible wire on leaching rate and largest Lyapunov exponent (LLE) were investigated experimentally. The results showed that rigid-flexible impeller changed structure of flow field and improved the fluid chaos mixing degree through coupling interaction of rigid-flexible-fluid. At leaching time 120 min, agitation speed 225 r/min, off-bottom clearance h=T/4, diameter of wire d=0.42r and length of wire L=1.3T, LLE of rigid-flexible impeller reached 0.9071 and leaching rate of phosphate rock increased by 10.8%. At the same power consumption (P _v=9860 W/m³), the suspension uniformity and the slag phosphorus content were reduced by 40.8% and 17.67% with the rigid-flexible impeller, respectively. In addition, the morphology of the crystal was improved when the rigid-flexible impeller was used. Meanwhile, the filtration performance of phosphogypsum was enhanced.

Pile-based borehole heat exchangers (energy piles) can be used as terminal heat transfer devices for ground source heat pumps, playing the role of conventional pile foundations at the same time. Thus, not only their heat transfer performances must be good enough to meet heating or cooling air conditioning demands, but also the stress changes caused by intermittent heat extraction and release alternatively from and to the soil surroundings should not endanger the stability of building structures above. To reveal the thermo-mechanical characteristics of energy piles sufficiently, the software of Comsol and Abaqus were implemented jointly to establish a three-dimensional dynamic numerical simulation model for an energy pile with double-U pipes buried in parallel. Simulation results were validated by the data obtained during an in-situ test. Dynamic temperature distributions inside pile body, axial force distributions and the displacement of the pile body were analyzed. The heat transfer performances and mechanical characteristics of four energy piles in different ratios of pile length-to-diameter with double-U pipes buried in parallel were studied under the conditions of different water flow rates, as well as those of energy piles with three different forms of buried pipes. The results show that the influence of the form of the buried pipes and that of the length-to-diameter ratio of the pile on their heat transfer and mechanical performance are significant, and the influence of the flow velocity is weak. The larger the length-diameter ratio and the flow velocity, the greater the heat transfer capacity, the larger the temperature difference between the inlet and outlet water. And the additional pile axial forces, pile top displacements and side frictional resistances caused by temperature changes increase as well accordingly.

The system combining the solar water and phase change heat storage Kang is put forward. Instead of water tank, Kang plate and phase change material are used as heat storage devices to availably improve the heating efficiency in this system. Based on Fluent, two-dimensional unsteady heat transfer model of the Kang is established. The heat storage and release characteristics of phase change Kang is studied and compared with the thermal properties of concrete material Kang. The effects of phase change temperature and latent heat of phase change materials on the heat storage and release characteristic of Kang are also analyzed. Under the working condition of this article, the stable temperatures of the upper surface of Kang of day and night increase by 2℃ and 4℃, respectively. The largest surface temperature difference of Kang decreases from 3.7℃ to 0.8℃. The heat increased by 66.36%. The phase change heat storage Kang has the advantages of high temperature of the upper surface of Kang, uniform temperature distribution, good heat-insulation property and large heat storage capacity. Results show that the temperature of the upper surface of Kang at night increase significantly, with the increase of phase change temperature, but the heat gain of Kang is reduced. Increasing the latent heat has little effect on the temperature of the upper surface of Kang, while significant effect on the heat gain of the Kang.

To test the effect of lubricating oil on the boiling heat transfer characteristics of carbon dioxide flow, the heat transfer of CO₂/lubricating oil mixture in a compact channel with an outer diameter of 6 mm and an inner diameter of 4 mm was experimentally studied at mass flow rate of 2.74—5.61 kg·h^-1, saturation temperature of -4—8℃, heat flux of 3.2—5 kW·m^-2 and oil concentration of 0—6%. The results show that the higher the concentration of lubricating oil, the smaller the local heat transfer coefficient of CO₂ and the delay of dryout. The average heat transfer coefficient with 1.5% oil concentration was reduced by about 42.4% compared with that without oil. With the increase of mass flow rate, the initial dryness of drying increased, and the heat transfer coefficient increased with the increase of mass flow rate. The heat transfer coefficient increases with the increase of heat flux and saturation temperature. Dryout is delayed with decreasing heat flux and increasing saturation temperature. Dryout characteristics have significant influence on heat transfer coefficient, and dryout stage accounts for 35.4% of the whole heat transfer process.

To obtain the heat transfer law of supercritical CO₂ under high heat flow and low flow rate, the experimental study on convective heat transfer of supercritical CO₂ in a small circular tube with an inner diameter of 2 mm was carried out, and the effects of variable properties, buoyancy and thermal acceleration were discussed. The operating parameters were as follows: system pressure p = 7.6—8.4 MPa, mass flux G = 400—500 kg/(m²?s), heat flux q = 0—200 kW/m², fluid temperature T _b = 20—62℃, and Reynolds number Re = 1.23×10⁴—4.3×10⁴. The dimensionless parameters of Gr/Re ² and Kv were adopted to represent the buoyancy effect and thermal acceleration, respectively. The results show that the buoyancy effect is significant (Gr/Re ² > 10^-3) under high heat flux and low mass flux conditions, and the heat transfer coefficients at top wall are always lower than those at bottom wall for a certain section. The buoyancy effect is the main factor that cause heat transfer deteriorate, while the thermal acceleration criterion is insignificant (Kv < 8.5×10^-7) and thus can be neglected. The experimental data were compared with typical heat transfer empirical correlations, in which the Liao-Zhao correlation fit well with the experimental data.

The process of calcium-catalyzed secondary reaction of coal pyrolysis tar is complicated, and it is difficult to deeply explore its mechanism through experimental research methods. The effect of calcium on the reaction of phenol (tar model compound) was studied using ReaxFF molecular dynamics simulations. The results showed that calcium promoted the reaction rate of phenol, and promoted the conversion of phenol to gaseous, heavy tar and coke products. At low temperatures, very little amounts of gas-Ca were observed. Ca was mainly involved in a repeated bond-breaking and bond-forming process between tar and coke. Ca species only promoted the polymerization of phenol at the low temperatures. While at high temperatures, a large amount of Ca was released in the form of gas-Ca, promoting the cracking of phenol. Ca promoted the production of H₂, but had little effect on the production of CO. The activation energies for the polymerization and cracking of phenol are determined to be 52.96 kcal/mol and 16.08 kcal/mol in the absence of Ca, compared to 37.33 kcal/mol and 13.34 kcal/mol in the presence of Ca. This means that the role of Ca in reducing the activation energy for phenol polymerization is much more significant than that for phenol cracking reactions.

Regeneration experiments of La modified multistage pore HZSM-5 zeolite were carried out at different regeneration temperatures by non-thermal plasma (NTP) spray system with oxygen as gas source. The physicochemical properties of La modified multistage pore HZSM-5 zeolite before and after regeneration were characterized by TG, XRD, Py-IR and N₂ adsorption-desorption. The experiments of on-line catalytic upgrading of bio-oil were carried out over regenerated catalyst. The results showed that when regeneration temperature was 250℃, the deactivated La modified multistage pore HZSM-5 zeolite had the best regeneration effect, 97.4% of coke was removed, and the surface crystallinity, acidity, specific surface area and pore volume recovery were the best. When regeneration temperature rose to 300℃, the decomposition amount of O₃ was more. At this time, the decomposition of O₃ had become the limiting factor for oxidative decomposition of coke. The peaks of CO₂ and CO concentration decreased, and the regeneration effect of deactivated catalyst declined. When regeneration temperature was 250℃, the catalytic performance recovery of regenerated catalyst was the best. The bio-oil produced by regenerated catalyst had the highest heating value (36.48 MJ/kg) and the highest hydrocarbon content (40.51%), and its physical and chemical properties were closest to that of bio-oil produced by fresh catalyst.

A partial diabatic distillation with side streams was studied by separating a binary mixture of n-propanol and isopropanol as an example. In the rectifying section, the vapor stream was withdrawn from the column and after condensation by the inter-condenser outside the column, it was then returned to the appropriate position above the output tray. In the stripping section, a jacketed inter-reboiler was set on the side of the section with the liquid inlet on the specific tray. The vapor stream in equilibrium was withdrawn from this tray and returned to its above appropriate position. The single-factor analysis and response surface method were used to simulate and optimize the relevant process parameters of the proposed operation in the rectifying section and the stripping section. The thermodynamic performance and separation performance of the scheme under the corresponding conditions were analyzed and showed that the exergy loss of the diabatic distillation with side streams was reduced by 26.5% as compared to that of adiabatic distillation when they had the same separation performance. The partial diabatic distillation with side streams achieves energy saving by rationally energy distribution, the energy quality reduction of heat and cold sources, and the improvement of energy-using efficiency.

Based on the NRTL activity coefficient model, the whole process simulation and process parameters were optimized by using Aspen Plus for extractive distillation equipment for aromatics recovery from different single component extractants. With consideration of multiple variables and their interactions, a coordinative optimization strategy was further proposed from iterative optimization of local coupling parameters. At given separation specifications, energy consumption was optimized through adjusting critical operating parameters, such as the feed stages of extractive distillation column(EDC), the feed stage of entrainer recovery column(ERC) and the reflux ratio of ERC. An energy consumption model correlated with physical properties was presented based on the energy transfer rules. A solvent evaluation model based on the energy consumption objective for aromatic extraction distillation processes was put forward through the analysis of energy consumption and separation efficiency with different solvents. The results show that the molecular weight and boiling point of solvent are the pivotal factors influencing the energy consumption of aromatics extraction distillation units. There is a high correlation of the energy consumption model with the R ² value bigger than 0.9 which can guide the selection, evaluation and design of the extracting solvent for an aromatic ED process.

A new type of hydrocyclone with a tangentially slitted structure is designed. The experimental study on the effect of the length, position, number and style of the slit on the separation performance of the hydrocyclone is carried out. It is shown that compared with the traditional hydrocyclone, the pressure drop of the slit-cone hydrocyclone is significantly reduced. The separation efficiency of the hydrocyclone tends to increase at first and then decrease when the length of the slit increases from 10 mm to 50 mm, and an optimal slit length of 20 mm is observed. In the process of moving the 20 mm slit upward from the first 6 mm slit at the bottom of the cone, the influence of the second slit position on the separation efficiency of the hydrocyclone is similar to that of the slit length. That is to say, it tends to increase at first and then decrease, and there is an optimal distance of 80 mm between the first slit and the second one. When keeps the cross-section area of the slits equaling to that of underflow in the traditional hydrocyclone under the conditions of optimized slit length and position, it is found that the separation efficiency of one slit in the cone is better than that of two, and the style of two-slits located at opposite direction is the best among all the cases investigated. Compared with the classical hydrocyclone, the separation efficiency in the optimal slit-cone hydrocyclone can decrease only 1.48% while the absolute pressure drop can reduce as high as 36.84% at a high flow rate. Therefore, it is a promising hydrocyclone for industrial applications to save energy consumption.

Study on water-salt mass ratio and phase behavior during the K-Mg mixed salt transformation from magnesium sulfate-type salt lake is important for preparing Pic (Picromerite). Pic was prepared from the K-Mg mixed salt of Yiliping salt lake in Qaidam Basin by means of transformation-flotation. Phase behavior was researched which was the initial and new produced by transformation. The results showed that the dissolution rate of the initial phase Car (Carnallite) and Bis (Bischofite) was the fastest, and the new phase KCl (Sylvite) was obtained by decomposition. The dissolution and transformation rate of the initial phase Kai (Kainite) and the new phase Pic transformed from Kai was second, and while the water-salt mass ratio was higher than 0.40, the rate tended to be flat. The dissolution rate of the initial phase NaCl (Halite) was always the lowest. During the transformation, KCl only dissolved, didn’t react with Pic to form a new phase SOP (potassium sulfate). Experimental results of the K-Mg mixed salt transformation were in good agreement with theoretical calculation results, the relative error was less than 4% between them, the theoretical calculations of the metastable phase diagram could be used to guide the K-Mg mixed salt transformation better. Finally, the obverse flotation collector had stronger capacity for collecting and adsorbing the K-containing phase than the reverse, the total yield of K had been reached 66%.

Using cyclohexanone oxime and sulfuric acid as raw materials, the hydrolysis of cyclohexanone oxime under continuous reaction-extraction coupling technology was studied to prepare hydroxylamine sulfate. The continuous reaction-extraction conditions were optimized. Cyclohexanone which as another product of hydrolysis reaction was separated from the original reaction equilibrium. This technology broke through the limits of the original reaction equilibrium, it greatly improved the conversion rate of cyclohexanone oxime. The results showed that the best reaction conditions were: cyclohexane used as the extraction agent, the ratio of oxime to acid 1∶1, the rotational speed 2000—2500 r/min, and the volume ratio of sulfuric acid solution to cyclohexane 1∶1. At the same time, when the raw material was fed from the heavy phase and extracted by five-stage series countercurrent reaction, after 90 min, the reaction basically reached equilibrium. After four cycles of extraction, the conversion rate of cyclohexanone oxime could reach 81.90%.

When the chemical process changes in a wide range of working conditions, the complex migration control strategy will bring certain operational uncertainty, so it is necessary to make a selection decision on the control strategy. Intuitively, the simplest approach for the judgment of control strategies is mapping the relationship between the production index and the factors which cause the process transition. The fitting error of the mapping relationship is obvious for complicated chemical processes. The intermediate variables are introduced for decreasing fitting error, and intermediate variables based judgment method is proposed for complicated chemical processes. In details, there are three basic principles for building the intermediate variables. Firstly, the intermediate variables consist of measurable process variables; secondly, the intermediate variables are insensitive to the type of process transition factors; thirdly, the intermediate variables are sensitive to the production index of the process system. Furthermore, based on the simulation of a commercial ethylene column, the introduction of the intermediate variables is beneficial to decrease the estimation error of production index. The usability of the intermediate variables based judgment method is verified for the control of large-range conditions change.

The simulation of hydrogenation of acetylene in slurry reactor was carried out. The TFM-PBM coupling method was used to describe the flow of gas phase and slurry phase in slurry bed, and the kinetics of acetylene hydrogenation reaction was coupled to establish flow-reaction synthesis. The model was validated in a lab-scale slurry bed reactor and was then applied to the simulation of a bench-scale slurry bed reactor with respect to the function mechanisms of internals and the effects of operating conditions. Simulation results showed that vertical tube in the bench-scale reactor can break up bubbles and suppress the radial flow of gas phase, which benefits the uniform and sufficient conversion of acetylene. The conversion of acetylene is closely related to the residence time of gas phase and the reaction temperature. In order to obtain complete conversion of acetylene and high selectivity of ethylene when the slurry bed reactor was scaled-up to an industrial scale, it is critical to control the reaction temperature and the residence time of gas phase which can be regulated by changing the height of the liquid phase.

Aiming at the problems of excessive energy consumption (EC) and exceeded seriously effluent quality (EQ) in wastewater treatment control process, an optimal control of wastewater treatment process using a multi-objective uniform distribution NSGAII algorithm (UDNSGAII) was proposed. Firstly, EC and EQ of wastewater treatment are regarded as optimization objectives, and the multi-objective optimal control model is established. Secondly, to obtain the optimal set values of dissolved oxygen (DO) and nitrate nitrogen (NO), and improve the performance of Pareto solution, the individuals which have been clustered are mapped to the hyperplane of the corresponding objective function, then, the diversity of population is increased. In addition, the distribution judgment module and distributed enhancement module are used to improve the distribution of solutions. Finally, PID controller as the bottom controller is used to track the optimal setting value of DO and NO. To test the effectiveness of the proposed algorithm, benchmark simulation model No.1 (BSM1) is used. The results show that the proposed UDNSGAII multi-objective optimization control method can effectively reduce EC of wastewater treatment process while meeting EQ standards.

In vitro digestion and fermentation experiments should be closely combined to simulate the function of the intact gastrointestinal tract. However, the existing simulated reactors for gastrointestinal digestion and large intestinal fermentation have different structures and are not universal. Combining the separated reactors would increase the complexity and the cost of the experiments. Integrated the dominant features of both types of reactors, a gastrointestinal simulation reactor(GSR) using a programmable logic controller(PLC) was developed in the present work. The dynamic characteristics of overall gastrointestinal tract were simulated and compared to the data in vivo. It shows that the developed reactor can accurately simulate the dynamic characteristics of peristalsis, emptying and mixing in the stomach and small intestine, and provide a fermentation environment for intestinal microbes. The exhaust gas discharge and collection device was considerately designed, the exhaust gas was quickly discharged and the volume could be accurately measured. The gastrointestinal simulation reactor can help to explore the role of prebiotics in intestinal microbes in vitro.

Silica was modified by a polyethyleneimine (PEI)/dopamine (DA) co-deposition method, and then carbonic anhydrase (CA) was covalently immobilized via glutaraldehyde (GA). First, the effects of the mass ratio of PEI and DA, deposition time on the deposition rate were investigated, and silica microspheres before and after modification were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Then, the influences of the immobilization conditions including the deposition rate, the addition amount of PEI/PDA-SiO₂, CA and GA concentration on the activity recovery of immobilized enzyme were studied. At last, the storage stability and reusability of immobilized enzyme were also examined. The results show that the deposition rate increased firstly and then decreased with the mass ratio of PEI and DA increased, and reached the maximum at a mass ratio of 1∶1. The deposition rate increased linearly with the time prolonged, which respectively reached 1.33% and 0.5% after 10 h for PEI/DA co-deposited system and pure DA-deposited that. The deposition rate had no obvious effect on the content of N element and activity recovery of immobilized CA. For enzyme immobilization, there was a saturated addition amount of the carrier which was 0.25 g PEI/PDA-SiO₂/mg CA, and the optimal concentration of CA and GA was 0.8 mg/ml and 0.1%(mass), respectively. Under these conditions, the activity recovery of CA-PEI/PDA-SiO₂ was about 78.8%. After 30 days of storage at 25℃, the remaining activity of immobilized CA was 77.2% while that of free CA was only 12%. The relative activity of immobilized CA was 88.3% after undergoing 10 cycles.

XPS, static contact angle, particle surface charge, scanning electron microscopy, functional group analysis and other methods were used to study the difference of physicochemical properties of alkali lignin after alkali-soluble dialysis and alkali-soluble acid precipitation treatment, and to explore the degree of alkali lignin molecular aggregation to Pb²⁺ removal. The results indicate that (1) after alkali-dialysis treatment, the specific surface area is 4.77 times compared with alkali-acid precipitation, and the contact angle of the water/lignin film decreased by 13° compared with alkali-acid precipitation, reflecting the degree of aggregation of lignin molecular is low and the molecular chain is loose; (2) the surface oxygen content increased by 48% compared with alkali-acid precipitation, reflecting the exposed degree of oxygen-containing functional groups such as carboxyl groups and hydroxyl groups are increased, so that the electrostatic interaction between the sample and Pb²⁺ is enhanced; (3) the lead ions removal performance is remarkably enhanced, while the removal capacity can reach 136 mg·g^-1 and the removal rate can reach 81.8% at the concentration of Pb²⁺ was 100 mg·L^-1, and the removal performance is little affected by the pH of the system. Compared with the chemical modifications and surface functionalizations which aim at improving the removal performance of lignin, the alkali-dialysis treatment has the characteristics of low toxicity and low energy consumption in the preparation process.

The vanadium slag roasting and vanadium extraction technology is inefficient, and the process involves chemical reaction, transmission and phase transformation process, and contains the dynamic behavior of fractal phase growth. The study of fractal variation of vanadium slag is conducive to promoting the directional transformation of vanadium and has a guidance for industrial vanadium extraction. According to the metallographic electron micrograph, the fractal dimension of vanadium slag powder under different roasting conditions was calculated by using the “circumference-area method”, and the variation of fractal dimension and phase transformation was obtained, and the law of fractal dimension change and phase transformation was obtained. The results showed that silicon phase and vanadium phase were packed tightly before roasting, and the value of fractal dimension was 1.60－2.00. The spinel was destroyed and vanadium phase was separated gradually after roasting with sodium carbonate, causing the fractal dimension to decrease below 1.20. With the increase of sodium salt addition, the fractal dimension gradually reduced. The second roasting made the system tended to be stable with sodium vanadate formed, and the fractal dimension further reduced to 1.10－1.20.

The continuous extraction method was used to extract the Zhundong high-sodium coal from Xinjiang, and the Zhundong coal samples containing different forms of sodium were prepared. The water-soluble sodium, ammonium acetate-soluble sodium and dilute hydrochloric acid-soluble sodium were investigated on a small fluidized bed. The results showed that the concentrations of carbonaceous gases and carbon conversion efficiency were significantly improved for water-washed ZD (WW-ZD) compared with untreated ZD. However, poor reaction properties of ammonium acetate washed ZD (AAW-ZD) and hydrochloric acid washed ZD (HAW-ZD) were obtained during a CLC process. The kinetics analysis on the isothermal gasification of ZD char with different extraction level was also investigated. The results showed that the activation energy of WW-ZD-H₂O was minimal while the activation energy of HAW-ZD-H₂O was maximum. It indicated that the H₂O-soluble sodium plays a prohibitive role during the CLC of ZD, while the CH₃COONH₄-soluble sodium and HCl-soluble sodium have a distinct promotion effect on CLC combustion performance of ZD.

Characteristics of the reduction reactions between transition metal oxide oxygen carriers (OCs) including MnO₂/Al₂O₃, Fe₂O₃/Al₂O₃ and CuO/Al₂O₃ prepared by an impregnation method and CO in converter off-gas were investigated using a fixed bed reactor and a thermogravimetric analyzer. Surface area analysis, pulse chemisorption and scanning electron microscopy were used to characterize the cycle life performance of CuO/Al₂O₃. The results show that CuO/Al₂O₃ exhibit the best reactivity among the three OCs, and the CO conversion at the reaction time of 2 min reach 90% when the reaction temperature is 225℃ or higher. Moreover, CuO/Al₂O₃ can maintain the high and stable performance of CO removal and mechanical strength at 350℃, a gas hourly space velocity (GHSV) of 4000 h^-1 in the reduction reaction and a GHSV of 159 h^-1 in the oxidation reaction, exhibiting an excellent redox cycle life. Based on these findings, a new process based on CLC has been proposed, with which the intermittently discharged converter off-gas can be safely utilized, thereby achieving the continuous heat supply to users.

Polyacrylamide (PAM) was used as the main chain skeleton, glutathione (GSH) was used as the grafting monomer. According to the Mannich reaction mechanism, condensation was carried out under the participation of formaldehyde, GSH was grafted onto PAM, and the polyacrylamide-glutathione (PAM-GSH) containing multiple coordinating groups was finally prepared. The PAM-GSH was characterized by FTIR, SEM-EDS and TG-DSC. The results showed that PAM-GSH is a thiol-functionalized PAM with pleated and porous pores. It has a network structure, which enhances its adsorption and sweeping net catching ability, and has good thermal stability in the range of 26—200℃. The coagulation experiment indicated that when the dosage of PAM-GSH was 84.48 mg/L, the concentration of Mn(Ⅱ) was 10.0 mg/L, the initial turbidity was 10.40NTU, and the initial pH value was 9.0, the best removal efficiency of Mn(Ⅱ) could be achieved. The existence of K(Ⅰ) and Al(Ⅲ) inhibited the removal of Mn(Ⅱ). Zeta potential analysis showed that the flocculation mechanism of PAM-GSH was mainly chelation, adsorption bridging and sweep netting.

The influences of Fe₂O₃ on glycine pyrolysis characteristics, generation mechanisms of NO _x precursors and transformation characteristics of nitrogen were investigated by DSC-MS and fixed bed experiment. The results indicated that the first thermal weightlessness stage of glycine (Gly) was divided into two parts by Fe₂O₃, so that the whole pyrolysis process was increased from 2 to 3 stages. Moreover, Fe₂O₃ can not only reduced the pyrolysis initiation temperature and the temperature of gas evolution by 50℃, but also promoted the secondary cracking reaction of char, which increased the weight loss rate of Gly by 23%. Furthermore, the evolution process of N-containing gases was divided into three independent stages by Fe₂O₃, which was corresponded to the Gly pyrolysis process. In the fixed bed experiment, most effective suppression of Fe₂O₃ on NO _x precursors (NH₃ and HCN) was achieved when the molar ratio of Fe₂O₃ to N is 0.5, which was decreased by 30%. Since Fe₂O₃ promotes peptide dehydration condensation, cyclization and aromatization reaction, more P-N, N-5 and N-6 are fixed in the semi-coke, and the semi-coke nitrogen residual rate is increased by 5%.

The introduction of alkali metal catalyst in the coal catalytic gasification process exacerbates the slagging of the gasification furnace and directly affects the normal operation of the fluidized bed gasifier. The sintering characteristic of coal ash is one of the main factors affecting slag formation in fluidized bed gasifier. In this paper a self-made pressurized pressure-drop measuring device combining analysis of X-ray diffractometer (XRD) analyzer and simulation calculation of Factsage thermodynamic software were used to study the effects of different additives addition on sintering temperature of Wangjiata bituminous coal from Inner Mongolia and gasification performance in catalytic coal gasification process. Silicon aluminum additives improved the sintering temperature of coal ash. Compared with silicon additives, the addition of high aluminum additives had more obvious effect on improving the sintering temperature of coal ash. High aluminum additives can be used as an efficient refractory flux, but it reduced coal gasification activity and catalyst recovery rate, it was because of the reaction of additives with catalyst in gasification, and thus the catalytic performance of catalyst decreased. Addition of calcium oxide, the ash fusion temperature and sintering temperature of coal ash increased, and the coal gasification activity and catalyst recovery rate also improved. The ash melting point and sintering temperature increased with the increase of CaO content. Calcium oxide can be used as an additive to improve the slagging properties of coal in catalytic gasification process. And the additive content should be determined according to the nature of coal and the characteristics of the coal gasification process.

Under the background of “Water pollution control action plan”, zero discharge of desulfurization wastewater has become the development trend of the era. The use of flue gas waste heat concentrated desulfurization wastewater to reduce desulfurization wastewater has attracted industry attention. During the pre-concentration of the flue gas, less SO₂ is transferred to the liquid phase to produce SO₃ ^2-, HSO₃ ^-, SO₄ ^2-. The sulfite nature is unstable and subsequent treatment will be affected. To explore the oxidation characteristics of sulfite under high salt water conditions in this process, the oxidation characteristics of sulfites were studied by oxidation-reduction potential(ORP) and dissolved oxygen. The study found that flue gas oxygen content promoted sulfite oxidation. The concentration ratio of desulfurization wastewater is positively correlated with the ORP value, which is beneficial to the oxidation of sulfite. Better sulfite oxidation during pre-concentration of flue gas, the oxidation rate can reach 94.7%, and no forced oxidation is required. This study is of great significance for controlling fouling during flue gas enrichment and reducing adverse effects on subsequent treatment.

Combustion characteristics of ethanol and dimethyl ether (DME) micro-jet flames were investigated experimentally and numerically. Four typical flames were observed in experiments of both ethanol flames and DME flames. The OH distributions of micro-jet flames were obtained by using OH-Planar Laser Induced Fluorescence (OH-PLIF) measuring system, the results showed that stable ethanol flames at relatively high velocities have smaller diameter and are slightly higher than counterparts of DME flames. Numerical simulation of ethanol and DME micro-jet flames were performed by numerical computations with a detailed chemical reaction mechanism, and the computed results agreed well with the experimental results. Reaction flux analyses of these two fuels were also performed with numerical calculation of one-dimensional non-premixed counterflow flame, which showed that there is a significant difference in intermediate species between the ethanol and DME flames. And the difference in chemical reaction characteristics leads to the difference in the flame structure of these two fuels.

Using sodium chloride as the driving solute, the forward osmosis membrane bioreactor (FOMBR) was used to treat domestic sewage, and the effect of reverse solute osmosis on the microbial community in the system was investigated. The abundance, community structure and clustering of microbial community were also analyzed. The results revealed that during the 20 d operation of FOMBR, the water flux decreased from 9.5 L/(m²·h) to 8.17 L/(m²·h), and the reverse salt flux increased from 29.52 g/(m²·h) to 35.06 g/(m²·h). Three samples (A1, A2 and A3) of mixed liquid sludge were collected on day 7, day 14 and day 20, respectively. The reverse solute osmosis had certain influence on the change of microbial community structure during the whole operation period. A total of 1496 OTUs were produced from the three samples of A1, A2 and A3. Shared OTUs were different for these three samples. The results also revealed that the reverse solute osmosis had less influence on the microbial community diversity and the abundance of bacteria in these samples. Samples A2 and A3 were closer together in the principal component analysis, which indicated that these two samples were more similar in composition. Heatmap clustering analysis also confirmed that A2 and A3 were more similar. The slopes of these three samples were small and very close, and the abundance of bacteria and uniformity of A1 and A3 samples were nearly the same. The structure of activated sludge communities in these three samples revealed high diversity at the level of phylum, class and order, and the abundance of bacteria in each classification level was different to some extent.

A typical civil decoupling coal-fired stove has two parallel furnaces, called a pyrolysis chamber and a combustion chamber, which are connected at the bottom, coal is introduced from the upper part of the pyrolysis chamber, and air is introduced through the inclined grate at the bottom of the pyrolysis chamber. Based on the profound understanding of both the nitrogen transformation route in coal combustion and the characteristics of gas flow circulation in decoupling stoves, the mechanisms of simultaneous reduction of NO _x and CO emissions in domestic decoupling coal-fired stoves were qualitatively analyzed in this paper. The influences of draft type and coal property on NO and CO emissions were experimentally studied further. The results indicate that the simultaneous suppression of NO _x and CO emissions in a domestic decoupling coal-fired stove can be mainly attributed to its unique geometry structure and draft type. Burning clean briquettes in decoupling stoves helps to reduce pollutant emissions significantly.

The PES ultrafiltration base membranes were prepared with PES, DMAc and TMA through the method of immersion precipitation phase inversion. Then PVA solution was coated on the base membranes surface and crosslinked by heating to obtain low molecular weight cut-off ultrafiltration membranes. The experimental results showed that with the increase of PVA concentration, the molecular weight cut-off first decreased and then increased; as the heat treatment temperature increased, the water flux decreased and the molecular weight cut-off decreased. When the PVA mass fraction is 0.1% and heat-treated at 80°C for 10 min, the molecular weight cut-off of the membrane was 900. The pure water flux was 6.10 L/(m²·h) . The cross-linking structure of PVA and TMA was confirmed by infrared spectroscopy analyzer.

CMC-g-P(MMA-DMDAAC) was prepared by emulsion copolymerization and trapping as well as encapsulation of 2,4-D via self-assembly resulted in the formation of 2,4-D/CMC-g-PDMDAAC nanoparticles. Its structure and morphology were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron (SEM) and dynamic light scattering (DLS). Furthermore, the encapsulation efficiency and sustained-release characteristics were investigated. The results demonstrated that the 2,4-D/CMC-g-P(MMA-DMDAAC) drug-loaded particles showed a cage structure with a particle size distribution from 160 nm to 425 nm. Moreover, the encapsulation efficiency increased as the molar ratio of monomers increased, which could reach up to 40.8%. In addition, the higher molar ratio of the monomers was, the lower cumulative release rate of the drug exhibited. Overall, the mechanism of release of 2,4-D from nanocarriers was consistent with Fickian behavior.

CO₂ adsorbents were prepared by chemical grafting ethylenediamine(EDA), diethylenetriamine(DETA), tetraethylenepentamime(TEPA), and polyethyleneimine(PEI) onto surface of graphene oxide combined with the ultrasound treatment. The pore diameter of amine functionalized GO is 1.35—4.34 nm, and the surface area is 98.032—210.465 m²/g. Among the four amine functionalized GO, the PEI functionalized GO has the largest CO₂ adsorption capacity, reaching 1.5 mmol/g at 70°C. Besides, the adsorbent also exhibited stable cyclic adsorption-regeneration performance with almost unchanged adsorption capacity after 20 cycles. The type of isothermal adsorption line is type Ⅰ, and the Avrami simulation results agree well with the adsorption experimental data.