Layered double hydroxides （LDHs） are two-dimensional layered materials composed of positively charged metal hydroxide laminates， negatively charged anions between the layers， and water molecules， which can store and release charge through the reversible oxidation-reduction reaction between hydroxide and oxyhydroxide. LDHs have the advantages of high theoretical capacity， adjustable morphology and composition， low cost， and easy large-scale preparation， and have become the supercapacitor electrode materials with increasing attraction in recent years. To date, the rate capacities of LDHs are far from the expectation due to the low activity associated with low intrinsic activity and small active surface area, and the slow charge transport kinetics arising from the poor intrinsic conductivity to hinder electron transfer and the narrow interlayer distance to impede ion diffusion. Various strategies have developed to increase the activity, e.g., by regulating compositions, amorphizating, nanostructuring and constructing hierarchical structures, and to facilitate the charge transport kinetics, e.g., by compositing with carbon, depositing/growing on conductive substrates, expanding interlayer distance, exfoliation-self-assembly. This review starts with the structural characteristics and energy storage mechanism of LDHs, and then summarizes the strategies for improving the rate capacities of LDHs. The up-to-date progress in achieving the high-rate capacity by matching electron transfer with ion diffusion is also included, which suggests a new avenue to explore the advanced LDHs for energy storage.

Selective catalytic reduction of NO with NH₃ (NH₃-SCR) is a well-established technology for eliminating NO_x from stationary source. Over the past decades, great progress has been achieved in China in developing practical SCR catalysts that can work well in power plant and other fields like coking industry at low and medium temperature range (180 — 420℃). However, the extension of SCR technology to ultra-low temperatures (e.g., < 150℃), which can meet the requirement of flue gas treatment from diverse non-electricity fields like cement kiln and industrial boiler, is still a big challenge. Ultra-low temperature SCR denitrification is usually located after the “dust removal-desulfurization” process. It has the advantages of simple flue gas composition, low energy consumption, and low transformation cost, which has attracted wide attention from researchers. In this mini-review, we first give a brief introduction on the current status of flue gas control from different industrial fields. Then, the catalyst systems (MnO_x, VO_x, CrO_x, activated carbon) that can provide good deNO_x performance under 150℃ are summarized, and the resistance property to H₂O, SO₂, alkali metals and ammonium nitrate species is emphasized. As well, the recent progress over pilot experiments for industrial application is introduced. Lastly, the prospect of ultra-low temperature SCR denitrification is discussed.

Spherical agglomeration technology can prepare spherical agglomerates by coupling crystallization and granulation in a same unit operation, which has the advantages of short process, low production costs and excellent product performance compared with the traditional fluidized bed granulation technology. However, it is still challenging in characterization, mechanism, industrial scale-up, and special crystallizer type. Based on this, this article summarized the characterization techniques and key indicators of spherical crystallization products and mainly introduced the progress of mechanism, mathematical models, new technology and equipment of spherical agglomeration with new ideas for future research and development. Finally, it prospects the development in industrial production, especially in the pharmaceutical field.

The process intensification of interfacial area and reaction conditions in multi-phase systems are important issues in industrially scaled reactors. In order to investigate the intensifying effect of micro-interface system on gas-liquid mass transfer and reaction rate, the ammonium sulfite oxidation was selected as the research object. A systematic air forced oxidation experiment was carried out through the micro-interface intensification reactor (MIR) and the traditional bubble column reactor (BCR) under the same experiment platform and operating conditions. The bubble size distribution and overall gas holdup were measured by high-speed camera technology and differential pressure measurement, respectively. The experimental results showed that MIR obtained higher gas holdup because of the micro-interface structure, the interfacial area was increased by more than 10 times, the reaction rate increased by 56.8% averagely compared with BCR. The experimental conclusions provide certain data support for the industrial application of the multiphase reaction system of the micro-interface intensification reactor.

The processing of hundreds of millions of tons of heavy oil into light distillates or chemical raw materials every year is related to Chinese national energy security and efficient use of energy resources. However, the traditional slurry-bed reactor (TSRs) for heavy oil hydrogenation is generally operated at very high pressure which causes a series of negative effects. Herein a new hydrogenation method called microinterface-intensified slurry-bed reactor (MISR) was developed for the low-pressure hydrogenation. The mathematical models regarding bubble Sauter mean diameter d₃₂ and gas-liquid interfacial area a as well as energy dissipation rate ε in the MISR were proposed for predicting d₃₂ and a. Also a cold-mode simulated experimental system was set up for the measurement of d₃₂ and a. Theoretical results showed that the mass transfer rate of hydrogen and its amount from gas phase into liquid phase in the MISR are much bigger than those in the TSR, which provides a theoretical basis for the efficient and low-pressure hydrogenation of heavy oil in the MISR. Experimental study displayed that d₃₂ in the MISR is in the range of 220 — 420 μm when the gas-liquid ratio (hydrogen/oil) changes from 10 to 150 in the practical operation conditions. Compared with TSR under high pressure operation, the gas-liquid interface area and hydrogen mass transfer rate in MISR are increased by 20 —100 times and 20 —50 times, respectively. Analysis shows that the errors between the theoretical calculation results of d₃₂ and a and the actual measured values ??are both within 15%.

The microbial aerobic fermentation process is a multi-phase biochemical reaction system, and the mass transfer rate of oxygen in air between the gas-liquid two phases has an important impact on the biochemical fermentation process. The transmission characteristics of oxygen in the bubble are the result of the combined influence of the bubble's morphology, movement and system temperature, pressure and physical properties. By establishing a two-component air bubble rising and its oxygen mass transfer coupling model, numerical simulation is used to describe the strengthening effect of the micro-interface system in the aerobic fermentation system. The energy dissipation theory is used to evaluate the energy consumption of the manufacturing microbubble system to obtain a cost-effective bubble shape and a high oxygen utilization rate. The calculation results show that, under the preset working conditions, in a reactor with a certain liquid level, the bubbles with an initial radius greater than 500 μm will escape the system in a short time, resulting in waste of materials; while the initial radius of bubbles is less than 100 μm, its residence time, mass transfer efficiency and oxygen utilization rate will be significantly improved. The generation of small bubbles requires greater energy consumption. Without considering the influence of other factors, if the DO value in the system is maintained at 20% to 30%, the maximum oxygen mass transfer rate can be obtained.

Particle viscosity is one of important parameters for the calculation of solid flow in Euler multiphase flow model, and the value depends on the frictional pressure and radial distribution function. The predictive ability of commonly used frictional pressure models (Based, Johnson) and radial distribution function models (Lun, Syamlal O’Brien) were evaluated by comparing them with experimental results. The simulation results show that the solid volume fraction using the Johnson model is lower than that using the Based model, and the solid mass flow rate using the Syamlal O’Brien model is much larger than that using the Lun model. The relative deviations of the average pressure drop can be reduced substantially after the Ergun coefficient correction was applied. The relative predicting deviations of the Based-Lun, Johnson-Lun, and Johnson-SO models were reduced from 68.6%, 73.3%, 78.2% to 13.2%, 29.7% and 42.3%, respectively. Comprehensively considering the pressure drop, the solid mass flow rate at outlet, solid volume fraction and the solid velocity in the near-wall area, the relative average deviations of the Based-Lun model is the smallest, and the Base-Lun model is suitable for simulation of the gas-solid Euler multiphase flow. In addition, this work found the Ergun coefficient and internal friction angle have a significant effect on solid velocity and pressure drop, while the threshold volume fraction for friction has little effect.

Supported catalysts are widely used in heterogeneous catalysis processes, in which the interfacial interaction between the active phase and the support and the influence of the interfacial density on the catalytic reaction mechanism and performance have always attracted attention. The main preparation method for traditional supported catalysts is impregnation method, in which a metal precursor is deposited onto the outer surface of support, normally rendering limited contact area and relatively weak interface interaction between the active species and the support. We use the reverse design idea to construct the surrounding catalyst, and develop a simple and universal preparation method, namely the ion exchange reverse loading method, so that the metal ions of the carrier precursor can replace the metal ions of the active metal hydroxide precursor through the ion exchange reaction. After calcination and reduction, a catalyst with an active core surrounded by a carrier is formed. The unique surrounded structure presents not only high interface density and mutually changed interface, but also high stability due to the physical isolation of active phase, revealing superior catalytic performance to the traditional supported catalyst, suggesting the great potential of this new surrounded catalyst as the upgrade of supported catalyst.

Developing an agitator suitable for wide viscosity range is of great significance to the energy saving and efficiency improvement by the intensification of fluid flow and mixing process. The power characteristics, flow field distribution, turbulence characteristics and mixing performance of multi-blade combined (MBC) agitator under laminar to turbulent flow state were studied experimentally and numerically at the level of large eddy simulation. The predicted power curve is consistent with the experimental results. Tangential flow is the main flow in laminar flow. With the increase of Reynolds number (Re), axial and radial flows in the vessel gradually increase. When Re reaches 486, the velocity field distribution is basically the same as that in the turbulent flow. At the same energy consumption level, MBC agitator is superior to the commercial Maxblend agitator in mixing high viscosity fluid. The intensification of axial and radial flows is due to the dispersed arrangement of the blades, enabling the MBC agitator to achieve larger axial and radial flows from the transitional flow to the turbulence state. Moreover, the turbulent kinetic energy is evenly distributed and the mixing process is significantly accelerated.

Ionic liquid supported liquid membranes have shown high CO₂ selective separation performance, but their low pressure resistance greatly limits their industrial applications. From the viewpoint of high cost and complex synthesis of crosslinkers used for crosslinking ILs, preparing IL-based gels by crosslinking diamino protic ionic liquids (PILs) with epichlorohydrin (ECH) was proposed in this work. The feasibility of this conception was confirmed via monitoring dynamical information of reaction system. The effects of protonation, reaction temperature and ECH-to-PIL molar ratio on the conversion of epoxy and chloride groups were systematically investigated. The gel transition property of these crosslinked PILs and the possible crosslinking mechanism were studied. Moreover, CO₂ permeation performance in crosslinked ILs was preliminarily tested.

The direct synthesis cyclic carbonate from styrene, O₂ and CO₂ is of great academic attraction and industrial value in modern chemistry. The metalloporphyrin/tetrabutylammonium bromide was employed as binary catalyst for this reaction in the presence of O₂ and CO₂ by using methyl 2-cyclopentanone-carboxylate as co-catalysts. The effects of reaction parameters on catalytic performance were investigated systematically. Under the optimal reaction conditions, conversion of styrene (99%) and selectivity to cyclic carbonate (35%) were obtained. The possible mechanism of cascade reaction was proposed by using in-situ ultraviolet and infrared spectroscopy. The results show that the cobalt center is coordinated with the ring oxygen atom of methyl 2-oxocyclopentanecarboxylate to activate oxygen to form a peroxy active species, thereby forming a high-valent cobalt-oxygen intermediate, which passes oxygen atoms to styrene and generate epoxy styrene. Then, styrene oxide opened ring under the catalysis of tetrabutylammonium bromide, and finally formed cyclic carbonate through CO₂ insertion reaction and intramolecular ring-closing reaction.

The supported catalyst PVAD/MoO₂/Ag was prepared by ion exchange and hydrothermal reduction using amino-functionalized polyionic liquid as the carrier, and its performance in catalyzing the oxidation of styrene was investigated. The prepared catalysts were characterized by FT-IR, TG, XRD, SEM and BET. The results showed that PVAD/MoO₂/Ag_4% showed the best catalytic activity. Under the conditions of acetonitrile as solvent, temperature of 90℃ and oxygen pressure of 0.8 MPa for 8 h, the conversion rate of styrene was 49.9%, and the selectivity of benzaldehyde reached 74.4%. Moreover, the activity did not decrease significantly after reused 5 times, showing good reusability.

Two kinds of Pd-Au bimetallic nanocatalysts (0.01% Pd-Au/1cTiO₂/SiO₂ and 0.05% Pd-Au/1cTiO₂/SiO₂) were prepared by using 1cTiO₂/SiO₂ as support, which had a single layer TiO₂ thin film on SiO₂ substrate by atomic layer deposition (ALD) technique. Deposition of Au and Pd on 1cTiO₂/SiO₂ was carried out by means of deposition precipitation and impregnation. Au loading of the two catalysts was both 0.01%(mass), and the Pd loading were 0.01% and 0.05% respectively. The prepared catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS), and the morphology of nanoparticles, the chemical valence state and composition of Pd and Au elements were determined. The Pd-Au bimetallic nanocatalysts were used in the selective epoxidation of cyclohexene using oxygen as oxidant, and the conditions such as the reaction solvent, the type of co-reductant and the reaction temperature were screened. The applicability of the catalyst to different structural olefins was investigated under the optimized reaction conditions. For cyclic olefins, the substrate conversion rate is greater than 95%, and the epoxy product selectivity is greater than 91%. After the catalyst is recycled 5 times, the catalytic activity and reaction selectivity remain unchanged.

Porous Ni/SiO₂ catalysts were prepared by electrospinning using P123 as template and the catalytic performance in CO methanation was evaluated. The synthesized catalyst was characterized by N₂ physisorption measurements, scanning electron microscopy (SEM), X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H₂-TPR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The results showed that Ni particles were highly dispersed on the silica nanofibers. The presence of pore structure in electrospun fibers immensely increased the specific surface area. Moreover, the porous Ni/SiO₂ catalyst exhibited small particle size and strong metal-support interaction, which led to excellent catalytic activity with 96.4% CO conversion and 86.4% CH₄ selectivity at 450 °C under 0.1 MPa with a WHSV of 15000 ml/(g·h). The 100-hour lifetime test indicated that the porous Ni/SiO₂ catalyst had excellent stability. This method provides a new idea for the industrial preparation of methanation catalysts with high catalytic activity and without secondary molding.

A series of Co-N-C catalysts were prepared by a two-step process including pre-condensation and high-temperature calcination, as well as formamide was used as both nitrogen and carbon sources, and cobalt acetate was employed as the source of cobalt. Then the characterizations of XRD, TEM, N₂ adsorption-desorption, and XPS were carried out to investigate the morphology and textural properties of as-prepared Co-N-C catalysts. Moreover, the catalytic activity and reusability of such Co-N-C catalysts were further studied for one-pot synthesis of N-benzyl aniline from nitrobenzene and benzyl alcohol. The results demonstrated that the annealing temperature and nitrogen-doping have remarkable influence on the catalytic activity of Co-N-C catalysts. The Co-N-C/800 catalyst exhibited the best catalytic performance, in which the conversion of nitrobenzene was 99%, and the selectivity of N-benzyl aniline was 99% under 0.6 MPa nitrogen, temperature of 140℃, and reaction time of 12 h. The catalyst was used repeatedly for 5 times, and its activity did not decrease significantly.

Graphene has shown superiority for advanced carbon electrodes in supercapacitors， characterized by high power density but limited energy density. Combining pseudocapacitive materials with graphene can alleviate the problem. This work synthesized the three-dimensional strutted graphene (SG) via the ammonium-salt-assisted sugar-blowing method, and the self-supporting MnO₂/SG porous monolith was then constructed via growing manganese oxide (MnO₂) nanorod array on the SG support in hydrothermal process. When tested in supercapacitor， the MnO₂/SG hybrid electrode achieved a high specific capacitance of 343.6 F·g^-1 at a current density of 0.5 A·g^-1， exhibiting excellent cycling stability with 83.8% capacitance retention after 5000 cycles. The symmetric supercapacitor further showed a high energy density of 11.93 W·h·kg^-1 at a power density of 500 W·kg^-1. The impressive result indicates a promising prospect of the excellent MnO₂/SG hybrid to be applied to electrochemical energy storage.

The capture of sulfur dioxide (SO₂) with readily available and cost-effective ionic liquids (ILs) is one of the challenges for the application of ILs. Here, we synthesized the ILs mixtures with different molar ratios (3∶1, 2∶1, 1∶1, 1∶2, and 3∶1) of 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) to study their SO₂ absorption capacities. The SO₂ solubilities in these mixtures were investigated under different conditions. The SO₂ absorption capacities of [Emim][Cl]_x[OAc]_1-x at different temperatures and SO₂ partial pressure were measured. The results show that ILs can effectively capture SO₂. There exists a synergistic promotion effect between [Emim][Cl] and [Emim][OAc], resulting in quite high SO₂ absorption capacity. The [Emim][Cl]_0.33[OAc]_0.66 mixture can capture SO₂ (1.34±0.08) and (0.74±0.05) g/g at 1.0 and 0.2 atm(1 atm=101325 Pa), respectively. Comparing with the reported data, [Emim][Cl]_x[OAc]_1-x mixtures show obvious advantage for SO₂ capture. In addition, these ionic liquid mixtures have good reversibility for the absorption and desorption of sulfur dioxide.

NH₃ pollution has always been a key concern in chemical industry, environmental protection and other fields. The capture and recovery of NH₃ in industrial exhaust gas is of great significance. A novel class of phenol-based deep eutectic solvents (DESs) were constructed by using 1-ethyl-3-methylimidazolium chloride ([Emim]Cl) as the hydrogen bond acceptor, while phenol (Phe), resorcinol (Res) and phloroglucinol (Phl) as the hydrogen bond donors. The densities and viscosities of phenol-based DESs at different temperatures were determined in detail, and the density and viscosity data were correlated by empirical equations. In addition, the NH₃ absorption-desorption performance and absorption selectivity of phenol-based DESs were systematically investigated. It is found that the capacities of phenol-based DESs for NH₃ absorption are quite high, and the absorbed NH₃ can be released by heating and evacuating, with the capacities for NH₃ absorption remaining almost unchanged after several cycles. However, the capacities of phenol-based DESs for CO₂ absorption are quite low, indicating the excellent performance of phenol-based DESs for NH₃/CO₂ selective absorption. Finally, the interaction mechanism of NH₃ absorption in phenol-based DESs was studied in depth with the help of spectral characterizations and quantum chemistry calculations.

Xinjiang brine nitrate mine mainly contains six kinds of ions: Na⁺, K⁺, Mg²⁺, Cl^-, NO₃^-, and SO₄^2-, belonging to a high-element complex system, and its rational utilization and development require phase equilibrium studies at different temperatures as theoretical support. The phase equilibrium of the system Na⁺, K⁺, Mg²⁺//Cl^-, NO₃^-, SO₄^2--H₂O saturated with NaCl·2H₂O at -15℃ was investigated using the isothermal solution equilibrium method. According to the measured data, the phase diagrams were constructed. Only one double salt KCl·MgCl₂·6H₂O was found in the system. There are six invariant points and eight two-salt crystallization fields corresponding to NaCl·2H₂O+Na₂SO₄·10H₂O, NaCl·2H₂O+NaNO₃, NaCl·2H₂O+KCl, NaCl·2H₂O+KNO₃, NaCl·2H₂O+MgSO₄·7H₂O, NaCl·2H₂O+MgCl₂·8H₂O, NaCl·2H₂O + Mg(NO₃)₂·6H₂O and NaCl·2H₂O+KCl·MgCl₂·6H₂O. The crystallization area of NaCl·2H₂O+Na₂SO₄·10H₂O occupies the largest part because of its low solubility, and they will crystallize out easily from the mixed solution in the cooling process. Compared with the phase diagram of the system at 25℃, there are 5 types of double salts reduced, 19 zero variable points reduced, and the phase relationship is greatly simplified.

The presence of a mixing isolation regions in a stirred reactor is a major obstacle to enhancing fluid mixing. Breaking the symmetrical flow field structure in the stirred tank and destroying the mixing isolation area can improve the fluid mixing efficiency. The Matlab software was used to calculate the maximum Lyapunov exponent (LLE) and multi-scale entropy (MSE). The effects of different blade types, flexible blade length, flexible blade number, blade height from bottom and rotation speed on fluid mixing were compared. The results show that the rigid-flexible impeller with long-short blades (RF-LSB) can enhance the flow field structure more unstable and asymmetric with deformation and random vibration of flexible pieces, destroy the symmetry flow in the process of fluid mixing, induce the asymmetric flow field, and make more fluid into the chaotic state. When at 90 r/min and three pieces of flexible, the LLE of the RF-LSB is larger than that of rigid impeller and rigid-flexible impeller RF-LSB with increase of 20.22% and 7.98% respectively. The mixing time (θ_m) of the three systems [RF-LSB (three pieces), rigid impeller, rigid-flexible impeller] has an exponential relationship with the power consumption per unit volume (P_v). When P_v is constant, θ_m of the RF-LSB system is the smallest. Results showed that the RF-LSB (three pieces) is superior to rigid impeller and rigid-flexible impeller, which is more conducive to fluid chaotic mixing.

The traditional dust removal system has high efficiency in removing coarse particles, but the efficiency of removing ultrafine particles is very low. The efficiency of removing ultrafine particles in China??s coal-fired power plants has not reached the national standard. Wet phase transition agglomeration is the newest technology to remove the fine particles from the flue gas. Considering the particle properties and ventilation factors, the mathematical model for the agglomeration and growth of ultrafine particles is improved. The improved mathematical model is written into the population balance model, and the growth characteristics and removal efficiency of ultrafine particles in the tube bundle type phase-transition agglomerators and the corrugated plate type phase-transition agglomerators are simulated and compared. The results show that both phase-transition agglomerators can obviously improve the removal efficiency of ultrafine particles, but the cooling effect of the tube bundle type phase-transition agglomerators is better than that of the corrugated plate type phase-transition agglomerators. The tube bundle type phase-transition agglomerators can promote particle growth by 7.71 times, which is 1.4 times that of the corrugated plate type phase-transition agglomerators. The removal efficiency of the particle concentration of the tube bundle type phase-transition agglomerator is up to 64.7%, while the removal efficiency of the corrugated plate type phase-transition agglomerator is only 27.2%.

High-temperature heat pipe is the key technology for efficient heat transfer in high-temperature fields. To develop high efficiency heat pipes further and improve the heat transfer performance in industrial process, gravity heat pipes with molten salt as heat transfer medium was developed. A high-temperature heat pipe test bench was set up and effect of working fluids and inclination angles on the startup characteristics and isothermal performance of the gravity heat pipe was studied experimentally. The results showed that as the inclination angle was 45° and 60°, the startup characteristics of heat pipes with AlBr₃ and TiCl₄ as working fluids was the best respectively, while the isothermal performance of the heat pipes was the best as the inclination angle was 60°. The inorganic salts AlBr₃ and TiCl₄ are used as the heat transfer working medium, and the gravity heat pipe has good starting and isothermal properties.

Gas field development often adopts wet gas gathering and transportation schemes. Based on minimum interfacial shear stress criterion and velocity profile in liquid film with flat gas-liquid interface for stratified pipe flow, a new model for predicting the critical gas velocity is developed to find out when liquid accumulations occur in wet gas pipelines. The formula of interfacial shear stress is deduced from combination of liquid-film flow field description with gas momentum equation. After the surface of interfacial shear stress is demonstrated, the critical gas velocity can be easily obtained by derivation of interfacial shear stress with respect to liquid holdup. The new model is compared with other three typical models to evaluate their agreements with experimental critical gas velocities, and shows the best prediction precision.

Ultrasonic -assisted freezing has been widely used in food, medical and biochemical fields. To clarify the effect of ultrasonic wave on the variations of liquid-solid ratio and void ratio in freezing state, and to reveal heat transfer law in the process of freezing transformation, the mathematical model of ultrasonic droplet freezing was established which was combined with the theory of acoustics and heat & mass transfer based on the experiment. The droplet freezing state under the action of ultrasound was analyzed, and the heat dissipation caused by ultrasonic cavitation effect and heat production caused by ultrasonic thermal effect was compared. The result shows that the ultrasonic wave is helpful to bubble overflow on surface of the droplet, and the larger the overflow rate is, the smaller the liquid-solid ratio is in the freezing process; when the bubble overflows is certain, the smaller the droplet is, the larger the porosity is; when the ultrasonic wave is certain, the smaller the overflow rate is, the larger the porosity is in the freezing process; for the cooling and freezing process, there is a reasonable ultrasonic loading time for different ultrasound frequencies and intensities.

Choosing the appropriate interphase force model is the key to CFD modeling of liquid-solid fluidization dynamic characteristics. Measured overall solids holdups are validated by Richardson-Zaki correlation under steady-state operating conditions. Then five drag formulas including Wen-Yu, Gidaspow, Syamlal-O??Brien, Dallavalle and TGS are assessed in the contraction and expansion processes by using Euler-Euler two-fluid model with the kinetic theory of granular flow. Furthermore, the influence of the classical lift model suggested by Moraga et al. on CFD predictions and the influence mechanism of main inter-phase forces are discussed. The results compared with the experimental data show that the response time of bed contraction process predicted by Syamlal- O??Brien or TGS drag model is more accurate than those by the others. Moreover, TGS drag model shows the most reasonable prediction in overall solids holdup. For the bed expansion process, TGS drag model gives more reliable prediction in the response time and overall solids holdup than the other models. The main reason behind the best hydrodynamic performance with TGS drag model in this study is that the modeling basis of TGS drag model is consistent with the dynamic behaviors of particles in liquid-solid system. The lift model has little influence on the CFD results, and thus it can be ignored in the modelling of inter-phase force for the dynamic characteristics according to the homogeneous liquid-solid fluidized system investigated in this study.

The heat transfer experimental system and mathematical model of receiver tube are established to analyze the transient heat transfer performance of molten salt with heat flux of outer wall sudden change, molten salt velocity sharp reduction, heat flux of outer wall and molten salt velocity sharp reduction at the same time. The results show that when the heat flow on the outer wall of the tube changes suddenly (sudden increase or decrease), the temperature of the molten salt in the center of the tube at the inlet section of the heat absorption tube changes less, but the temperature of the tube wall changes faster. When the molten salt velocity sharp reduction, the outlet temperature of molten salt and the outer wall temperature increase with time, but the difference of outer wall and inner wall temperature decreases at first and then increases, when t≥16.0 s, each temperature and temperature difference reach steady state. When the heat flux on the outer wall of the heat absorption tube and the molten salt flow rate in the tube are halved at the same time, the temperature of the molten salt in the center and the outlet of the tube rises first and then decreases with the passage of time. After the steady state, the two molten salt temperatures maintain a constant value and are compared with the transient state. The corresponding molten salt temperature is close to initial starting temperature. The difference of outer wall and inner wall temperature after transient stability is proportional to the heat flux of outer wall, but which is independent of molten salt velocity. The outlet temperature equation of molten salt in receiver tube after transient stability is obtained, which provides a theoretical basis for the outlet temperature control of molten salt in receiver during the transient heat transfer process.

The traditional numerical simulation calculation time is long, and it is difficult to meet the needs of modern industry development. The method of combining body-fitted coordinates and proper orthogonal decomposition(POD) reduced-order model is used to calculate the heat transfer units of the flat tube fin heat exchanger. And its calculation results are compared with the results of the finite volume method (FVM). The results show that the POD method can accurately obtain the actual information under the boundary conditions of uniform wall temperature and uniform heat flux. But also, the calculation speed of POD is 3093 times of FVM. As for the cases of reconstructing the temperature field, the maximum error values under the boundary conditions of uniform wall temperature and uniform heat flux are 0.557% and 0.308%, respectively. As for the cases of reconstructing the velocity field, the maximum error values under the boundary conditions of uniform wall temperature and uniform heat flux are 1.26% and 1.9%, respectively. The conclusions of this study can supply theoretical reference for reasonable boundary condition in numerical design of the heat exchanger.

Heat transfer is one of the basic issues in chemical production, and thermal conductivity is an important thermodynamic data in the design of chemical product production processes. In this paper, nonequilibrium molecular dynamics methods are used to simulate the heat transfer of liquid alcohols at four different temperatures, and the thermal conductivity of the corresponding conditions is obtained. The average relative deviation between the calculated value and the experimental value was 3.77%. Through the decomposition of heat flux, it was found that molecular kinetic energy, Coulomb interaction and intramolecular dihedral angle contribute the most to the heat conduction of alcohols. At the same time, as the molecular volume increases, the thermal conduction pathway of the intramolecular interaction term gradually dominates, indicating that the thermal conduction mechanism of alcohols has a significant relationship with the molecular structure. In addition, as the temperature elevates, the heat flux transmitted through the molecular kinetic energy, intermolecular Coulomb interaction, and the intramolecular angle bending and bond stretching term increases, while the heat flux transmitted through the molecular potential energy decreases significantly. This work provides a microscopic explanation for the effects of the structure and temperature of liquid alcohols on thermal conductivity, and provides a micro foundation for the study of heat conduction of liquid alcohols.

Powder nano-manganese oxide (MnO_x) material with excellent low-temperature denitration activity was prepared by precipitation-calcination method with manganese sulfate as precursor. The industrial catalyst of ?5 mm×30 mm granular MnO_x was successfully produced by continuous extrusion molding technology. The produced industrial catalyst was applied in the denitration purification of low-temperature flue gas from cold, hot & electric triple supply(CCHP) system on the conditions of 5000 m³/h gas flow, 850—1000 mg/m³ inlet NO_x and the temperature from 145 to175℃. The NO conversion can achieve to 87.88%—97.47% under the GHSV of 4405 h^-1, and 3% decline of denitration efficiency was observed after use for 1180 hours. The laboratory test also confirmed the reduced activity for the used sample. Moreover, XRD, BET and SEM results showed the crystal transition, increased particle size and decreased surface area for the used MnO_x sample, which accounted for the observed decline of denitration efficiency after long term use on the industrial conditions. The results of this study will provide references for the preparation of highly active manganese-based catalysts and their industrial application in low-temperature denitrification.

Using pyridine bisulfate ionic liquid as a catalyst, the kinetic behavior of glycerol and acetate into triacetin was systematically studied. The effects of reaction temperature, molar ratio of acid to alcohol, and amount of catalyst on glycerol conversion and triacetin yield were investigated using single factor experiments. The reaction kinetic model was developed using the quasi-homogeneous first-order reaction theory. The pre-exponential factor and the reaction activation energy were obtained by fitting the kinetic experimental data. The results showed that the conversion of glycerol increased with increasing of reaction temperature and the molar ratio of acetic acid to glycerol. With the increase of the amount of catalyst, the reaction rate of glycerol increased gradually, but the equilibrium conversion remained essentially unchanged. Under the optimum reaction conditions of temperature at 110℃, the molar ratio of acetic acid to glycerol in 6∶1 and the catalyst dosage of 3%, the maximum conversion of glycerol and the maximum yield of glycerol triacetate were 98.5% and 40.4% respectively. The pre-exponential factors k₁₀, k₂₀ and k₃₀ of glycerol with acetic acid gradually forming monoacetin, diacetin and triacetin were 7.17, 14.19 and 13.78 min^-1 respectively. The corresponding reaction activation energies E₁, E₂ and E₃ were 19.10, 21.58 and 23.25 kJ·mol^-1 respectively. The calculated values by the kinetic model were agreed well with the experimental values. The catalyst has a better catalytic effect than that of the reported Amberlyst-15 and heteropoly acid catalyst with milder reaction conditions, higher selectivity, and lower activation energy.

The use of biodegradable plastics is an effective means of solving white pollution. However, the production of degradable plastics in bioreactors will face problems such as insufficient gas mass transfer capacity and excessive energy consumption, resulting in high production costs. To solve these problems, a new design of bioreactor with coaxial contra-rotating propellers is proposed as well as according flow analysis based on numerical simulation. To verify our numerical models, three different benchmarks including bubble plume, bubble column and stirred tank are performed. Drag force, lift force and turbulent dispersion force are included in our two-phase model. Standard k-\epsilon method is modified via Troshko-Hassan model to consider bubble induced turbulence. Additionally, sliding grid method is employed to simulated rotating turbine. The results show that phase interactions in two-fluid method have a significant influence on accuracy of simulation. Our final result agrees well with experiments and previous literature. As for new bioreactor, it is shown that shear force is enhanced between two turbines. Gas hold-up, dispersion capabilities and RPD(relative power demand) are improved in new bioreactor compared with traditional design.

A series of HZSM-5 molecular sieves with hierarchical porosity were prepared by acid and/or alkali treatments, and their pore structure and acidity were characterized by XRD, N₂ adsorption, XRF, TEM, ²⁷Al MAS NMR and NH₃-TPD. The characterization results show that the alkali treatment method used in this paper can generate the mesoporous structure with a pore size concentrated at 3—6 nm. By changing the order of acid and alkali treatment, the number of acid centers and the ratio of strong acid to total acid center can be adjusted. In addition, the catalytic performance of the hierarchical porosity catalysts were studied for the catalytic fast pyrolysis (CFP) of cellulose and rice straw to aromatics on the Py-GC/MS. Compared with the commercial HZSM-5, the catalysts (HZ-OH/H) obtained by alkali first and then acid treatment can increase the aromatics carbon yield of cellulose CFP from 32.3 % to 43.6%, and same for rice straw from 23.0% to 30.8%. The pore structure and acid center distribution characteristics of the multi-stage HZ-OH/H molecular sieve have reference significance for the development of high-efficiency industrial catalysts applied to biomass to produce aromatics.

The polymerization process of nylon 66 salt solution is a dynamically controlled process. Based on the assumption of unequal activity of functional carboxyl and amido groups, a new nylon 66 salt solution polymerization kinetic model was established by introducing the nylon salt dehydration reaction to the acid-catalyzed third-order reaction kinetic model and fitted to obtain the corresponding key kinetic parameters. The fitted salt dehydration reaction rate constant was 8.17×10^-3 kg?mol^-1?h^-1, while the activation energy was 19859 cal?mol^-1, respectively. Compared with Mallon model, the new developed model has a better fitting effect and can accurately predict the change of the polymerization process in a wider range of temperature and water content. Simulation results showed that salt dehydration reaction has an important effect on the polymerization process and the polymerization efficiency was relatively lower with higher concentration of nylon salt, especially under low temperature and high water content. Appropriately increase the reaction temperature or reduce the initial water content can accelerate the nylon salt dehydration reaction, thereby increasing the polymerization reaction efficiency. New nylon salt polymerization kinetics modeling method is not only applicable to nylon 66, but also to nylon 1212 and other salt solution polymerization systems.

Gas-liquid cylindrical cyclone (GLCC) is a separation device coupling centrifugal force and gravity. The distribution characteristics of the swirling liquid film along the upper cylinder wall of GLCC significantly affect its separation performance. The thickness is the key parameter of the swirling liquid film. Mastering its distribution law can lay the foundation for better understanding the flow mechanism of the liquid film. In this paper, the liquid film thickness in the upper cylinder of GLCC was measured by using button electrodes. And its spatial distribution characteristics were systematically studied by changing the gas-liquid flow-rate and the size of the inlet nozzle. The results show that the liquid film thickness tends to decrease in the axial direction when the operating parameters are constant. At a certain axial position, the liquid film thickness exhibits an “S” shape distribution with the increase of the inlet gas volume, and increases with the inlet liquid volume and nearly linear increase. In addition, the size of inlet nozzle had a significant effect on the distribution of liquid film thickness. The change of liquid film thickness with inlet gas-liquid flow-rate proved that the escape of liquid film was the direct reason for the decrease of liquid separation efficiency of GLCC. The influence of inlet nozzle??s size on the axial distribution of liquid film thickness reflected the interaction between swirl and gravity effects.

To improve the efficiency of active learning and reduce the cost of manual marking, a fast active learning method based on kernel extreme learning machine is proposed and applied to soft sensor research. Firstly, the information of unlabeled samples is evaluated by kernel extreme learning machine, and the confidence of unlabeled samples is taken as the evaluation criterion of sample selection. The most valuable unlabeled samples to improve the performance of the model are selected for labeling. Secondly, considering the operation information of each iteration process, the matrix inversion formula is introduced to optimize the sample selection strategy to improve the efficiency of sample evaluation. Finally, the matrix similarity theory is applied to measure the information of the labeled sample data in the iterative process, and it is used as the basis for the termination of the iterative process to improve the performance of the model with the minimum cost of labeling. The proposed method is applied to the study of H₂S and SO₂ concentration soft sensor in the sulfur recovery process. The simulation results show that the proposed method not only has low marking cost, but also improves the speed of iteration and the performance of active learning algorithm. By carrying out this research work, a new method is provided for the application of soft-sensing technology under the condition of less labeled samples.

It is difficult to deal with industrial hybrid systems involving both continuous and discrete variables using conventional data-driven fault detection methods. While logical analysis of data (LAD) methods are able to effectively explore hidden rules in discrete and continuous data by means of logical analysis for variable associations. However, conventional LAD has the problem of losing trend change information when extracting features of continuous variables. And when processing industrial data with high-dimensional, multivariate features, it will cause a lot of redundancy in the extracted rules. Motivated by these observations, this paper presents an extended logical analysis of data (ELAD) approach to fault detections of industrial hybrid systems. Therein, correlated variables are selected according to the association degree with key variables and additive variable trends are employed to characterize process status changes, creating an explicable fault detection model. The proposed method is applied to the steam drum process of an industrial coal gasification plant in detecting the influence of key hybrid variables on the fault of steam drum level. The results verify the feasibility and effectiveness of the contribution.

In order to excavate thermo-alkaline lipases from bacterial living in extreme conditions, we try to express new gene from Thermosyntropha lipolytica DSM 11003, an anaerobic, thermophilic, alkali-tolerant bacterium which grows in alkaline hot springs Lake Bogoria in Kenya and explore its application in biodiesel production. The lipase gene (tll1) of 1434 bp were ligated at the Nco I / EcoR I sites of the expression vectors pET28a to yield the construct of pET28a-TLL1. The strain harboring pET28a-TLL1 was cultivated for expression at 25℃, the specific activity of 1.99 U/mg protein were detected in disrupted cells. The recombinant lipase TlLipA was purified by a simple two-step procedure involving heat treatment and Ni-chelating affinity chromatography. The subunit of purified TlLipA showed a molecular mass of 53×10³ on 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The purified TlLipA exhibited optimal activity at 65℃ and pH 8.0 and it was stable from 55℃ to 65℃. The enzyme remained above 80% of its original activity at pH ranging from 7.0 to 11.0 and at room temperature for 1 h. The activity of TlLipA was little unaffected by Co²⁺, K⁺, Na⁺, and Ni²⁺, and a little activated by Mg²⁺ and Mn²⁺, ^{but were significantly inhibited by Zn2+, Fe3+, and SDS, and Tween 80 under the assay conditions. The purified recombinant TlLipA had a specific activity of 22.11 U/mg protein using p-nitrophenyl palmitate (p-NPP) as substrate. Determined by Sigma-Plot of reaction rate on p-NPP, the K_m was 0.23 mmol/L, the V_max was 33.50 mmol/(L·min), and the k_cat was 22.83 s-1. The enzyme was also active towards p-NPP, p-nitrophenyl laurate (p-NPL), p-nitrophenyl myristate (p-NPM) and p-nitrophenyl caproate (p-NPC), moreover TlLipA exhibited a strong preference for p-nitrophenol decanoate (p-NPD) and p-nitrophenyl octoate (p-NPO). Using recombinant lipase as a catalyst to prepare biodiesel in a solvent-free system, with a water content of 20%, an enzyme dosage of 200 U/g oil, and an alcohol-to-oil ratio of 4∶1, catalyzed soybean oil reaction at 55℃ for 48 h, the yield can reach 91.75%.}

Injecting inhibitors is the most commonly used method in the oil and gas industry to solve the problem of blockage caused by hydrate formation during pipeline transportation. However, most of the kinetic hydrate inhibitors (KHIs) are strictly limited by weak inhibition performance and low subcooling. Ionic liquids, a kind of green solvent, have been recognized to act as excellent thermodynamic inhibitors on methane hydrate formation. So, it is proposed to add the ionic liquids into KHIs to improve their overall performance. In this paper, the kinetic effects of an ionic liquid N-butyl-N-methylpyrrolidine tetrafluoroborate ([BMP][BF₄]), a commercial kinetic inhibitor polyvinyl pyrrolidone (PVP K90) and their mixtures with different mass ratios on the methane hydrate formation were experimentally studied at 8.0 K subcooling and two concentrations [1.0%(mass) and 2.0%(mass)]. The best mass ratio of the compound inhibitor was determined. Moreover, the crystal structures and cage occupancy characteristics of methane hydrates formed without and with inhibitors at different mass concentrations and composition ratios were measured by using powder X-ray diffraction (PXRD) and low-temperature Laser Raman spectrometers. It was found that the addition of inhibitors did not change the crystal structure of methane hydrate, but affected the cage occupancies and hydration numbers. Based on the results from macroscopic kinetics and microscopic structure tests, the inhibition mechanism of compound inhibitors was proposed.

LaMn_1-x-yFe_xCo_yO_3-δ perovskite-type composite oxides co-substituted with B-site Fe and Co were prepared by the sol-gel method, and used for the chemical looping partial oxidation of methane to syngas. The XRD results suggest that Fe and Co were incorporated into the lattice of LaMnO₃ and formed perovskite phase. Reactivity and stability tests show that LaMn_1/3Fe_1/3Co_1/3O_3-δ oxygen carrier has the best reaction performance. CH₄-TPR results indicate that LaMn_1/3Fe_1/3Co_1/3O_3-δ has higher methane activation and lattice oxygen migration rates than those of LaBO₃ (B=Co, Mn, Fe). CH₄-pulse reaction further confirms that the synergistic effect of B-site ion substitution can improve the surface reaction rate of LaBO₃ (B=Co, Mn, Fe). H₂-TPR results show that the lattice oxygen in LaMn_1/3Fe_1/3Co_1/3O_3-δ has moderate redox capacity, which is suitable for partial oxidation of methane.

Taking Zoige Wetland (soil A) in the upper reaches of the Yellow River, Baotou Nanhai Wetland (soil B) in the middle reaches, and the Yellow River Delta Wetland (soil C) in the lower reaches as the research objects, NH₄NO₃ and glucose were used as external nitrogen and carbon sources, respectively, and a 28 d constant temperature cultivation method was used. The effects of exogenous addition on daily average carbon mineralization rate (C_average), net nitrogen mineralization rate (NN_min), and net nitrification rate (NN_nitri) of typical wetland soil in the Yellow River Basin were studied. The results show that wetland types have significant effects on soil carbon and nitrogen mineralization and nitrification rates, and differences in soil physical and chemical properties are the main influencing factors. Carbon addition significantly increased C_average of different wetland soils and the most significant promotion was exerted on soil A. However, nitrogen addition had no significant effect on C_average. Addition level had significant influence on NN_min. Low level carbon addition significantly inhibited NN_min of soil C while had no significant effect on that of soil A or soil B. High level carbon addition significantly prevented NN_min of different wetland soils. Low level nitrogen addition had no significant effect on NN_min. High level nitrogen addition significantly inhibited NN_min of soil B and soil C, while had no significant effect on soil A. Exogenous addition had no significant effect on NN_nitri.

To solve the problems of lower removal efficiency of organic sulfide and large amount of by-products in the traditional wet desulfurization process, a novel wet catalytic hydrolysis system of carbonyl sulfide was developed. The system was constructed with application of polyethylene glycol dimethyl ether (NHD), N-methyldiethanolamine (MDEA), and water as desulfurization agent with optimal compositions of 25% MDEA/15% H₂O/60% NHD. The effect of the desulfurization operation parameters, reaction temperature, gas concentration and gas flow rate on the desulfurization of COS was investigated. Furthermore the possible mechanism and kinetic of the desulfurization process were proposed and determined in reference of the results of GC and IC. The results show that the removal efficiency of COS is above 80% under low temperature (298.15—343.15 K) and normal pressure. The absorption process conforms to pseudo-first-order reaction kinetics. The organic solvent contents in the developed desulfurization system is more than 85%, which can effectively avoid the production of by-products and consumption of alkali in the desulfurization system, and is expected to be treated as an alternative for COS removal with high desulfurization efficiency.

Based on thermogravimetric experiment (TGA) and density functional theory (DFT) calculations, the reaction activity and microscopic molecular reaction mechanism of Cu low-concentration doped Fe₂O₃ oxygen carrier (Cu-Fe₂O₃) and H₂ in the process of chemical looping combustion were studied. TGA results showed that the low concentration of Cu-doped reduced the apparent activation energy of Fe₂O₃ reaction with H₂ (from 83.9 kJ/mol to 72.3 kJ/mol). And improved the conversion rate and lattice oxygen release rate of Fe₂O₃ oxygen carrier, which was attributed to the introduction of Cu element. From the atom/molecular level, DFT calculations verified that the low concentration of Cu-doped altered reaction pathway of Fe₂O₃ oxygen carrier reaction with H₂. The calculation results showed that the energy barrier of Fe₂O₃ oxygen carrier reaction with H₂ decreased from 2.30 eV to 1.81 eV (Fe atom top site) and 1.68 eV (Cu atom top site), respectively. The reaction preferentially occurred at the Cu atom site, followed at Fe atom site. Furthermore, the micro-structure characteristic change of Fe₂O₃ oxygen carrier (Cu—O and Cu—Fe bonds introduced) is more favorable for the rapid lattice oxygen release in chemical looping process.

The Donnon dialysis-zerovalent iron combined process was developed by adding zerovalent iron into the stripping solution. The arsenic adsorption by the zerovalent iron corrosion products was able to regenerate the stripping solution in situ. Therefore, the long-term arsenic removal by the Donnan dialysis system was markedly improved. In this study, the effect of NaCl concentration in the desorption solution was determined to be 0.1 mol·L^-1 based on the investigation of the effect of the NaCl concentration in the desorption solution on the arsenic removal performance of zero-valent iron. Then, the proposed Donnon dialysis-zerovalent iron combined process was used to treat arsenic containing well water for multiple batches, using stripping solution containing 6 g common salt and 5 g zerovalent iron per liter. The arsenic concentrations in the treated water was constantly below 50 μg·L^-1 for 20 batches, much lower than the performance of the single Donnan dialysis system. The coupling of Donnan dialysis with zerovalent iron prolonged the interval for the stripping solution replacement; therefore, the practical application of the Donnan dialysis household water purifier was significantly improved.

In this study, the TiO₂ modified graphene composite material (RGO/ TiO₂) was prepared by hydrothermal method, and its morphological structure and electrochemical properties were investigated. Then RGO/TiO₂ material was assembled into electrode, and NH₄⁺ ions electrosorption efficiencies of unmodified graphene (RGO) electrode and the RGO/TiO₂ electrode were compared. The effects of applied voltage, circulating velocity and initial concentration on NH₄⁺ ions electrosorption by RGO/TiO₂ electrode were investigated. The characteristics of NH₄⁺ ions electrosorption and the effect of advanced NH₄⁺ ions removal from simulated actual wastewater containing NH₄⁺ ions were also studied. The results showed that the RGO/TiO₂ composite material had a three-dimensional pore structure with specific surface area of 382.08 m²·g^-1 and specific capacitance of 325.80 F·g^-1 at a scan rate of 0.01 V·s^-1, which were better than those of the RGO material. The initial adsorption capacity of RGO/TiO₂ electrode was 28.3% higher than that of RGO electrode. After 10 cycles of regeneration adsorption, the adsorption capacity of NH₄⁺ ions of RGO/TiO₂ electrode only decreased 5.87%, and its cyclic regeneration adsorption property was better than that of RGO electrode. In addition, the applied voltage 2.0 V, circulating velocity 35 ml·min^-1 and initial concentration 1.0 mmol·L^-1 were the optimal NH₄⁺ ions electrosorption conditions for RGO/TiO₂ electrode. The electrosorption process of NH₄⁺ ions by RGO and RGO/TiO₂ electrodes was in accordance with the quasi-first-order kinetic model and the Freundlich isothermal adsorption model. The electrosorption of NH₄⁺ ions was a multi-layer adsorption behavior on heterogeneous surface and physical adsorption was the dominant. When the RGO/TiO₂ electrode was connected in 4-stage series, the removal efficiency of simulated actual NH₄⁺ refining purified water reached 86.84%.

Using naphtha as raw material for cracking, the effects of adding sulfides and sulfur/phosphorus compounds on the coking behavior of thermal cracking were investigated. The morphologies and structures of the pretreated HP40 alloy specimen and coke deposits were characterized by Raman spectroscopy, XRD, SEM and XPS. The results showed that the addition of phosphide into the sulfide additives led to the change in the structure of coke deposits under the condition of continuous addition of additives into the feed. The method with continuous addition of sulfur/phosphorus-based compounds showed excellent anti-coking properties. The surface pretreatment with sulfur or sulfur/phosphorus-based compounds made the increase of Fe content in the oxide film on the specimen. So anti-coking effect was limited when the pretreatment method was applied. The coking inhibition property of the application of surface pretreatment with sulfide/phosphide followed by continuous addition of sulfur/phosphorus-based compounds were similar to that of the application of continuous addition of sulfur/phosphorus-based compounds in the feed. However, the combination method showed the better anti-coking effect during the initial cracking process. All the addition methods led to the increased amounts of amorphous coke in the coke layer and the decreased graphitization degree of cokes. The results of the low H/C ratios showed the highly condensed structure of the coke deposits during thermal cracking process. The addition of sulfur and sulfur/phosphorus-based compounds could influence the dehydrogenation reaction to some extent during the coke formation by reducing catalytic coking.

Premixed methane gas explosions caused by leaked natural gas pose a serious threat to the lives, which may lead to casualties and buildings collapse. So it is important to know the distribution of pressure fields around buildings when there is an explosion. Then people can escape to a relative safe place. Based on the Fluent software, a calculation model suitable for the overpressure of the unconstrained explosion of methane was established, and it was corrected by experimental data. The results show that highest accuracy appears in the SAS turbulence model and the Laminar Finite-Rate model when there is no object to limit the explosion, and that the volume of methane air mixture involved in combustion explosion at the stoichiometric concentration is about 1/3 of the total volume. Then a model for methane unconfined explosion is established. The influence of building height and width on the pressure field is analyzed. Furthermore, the distribution of pressure field inside the building is studied. And the results show that the middle-upper part of buildings is safer than the bottom when the building does not fail. The width of a building affects its resistance to positive overpressure. But neither the height nor the width of the building will affect the change of negative overpressure. Thus in the emergency explosion accidents, it will more vulnerable to the strong impact of positive and negative overpressure that escaping to the bottom blindly.

To measure the key free radicals of the gasoline-air explosion in long-narrow confined space accurately, which is important to the accurate analysis of the explosion flow field and the flame propagation, an experimental study on the gasoline-air mixture explosion in a long-narrow confined space is designed based on the planar laser induced fluorescence system (PLIF),and the experiments in different conditions of the gasoline-air explosion in long-narrow confined space are carried out. The concentration distributions of the OH radical of those are obtained. The results of experiments show that the concentration of OH radical rises and then descends among the gasoline concentrations of 1.1%—2.4%(volume fraction); the concentration of OH radical rises steadily along with the development of flame propagation, which means the explosion is strengthen; the distributions of the OH radical are different in different explosion stages, which means the combustion reaction area in different explosion stages differs a lot; there is a "isolation belt" between the flame and the wall, which is the result of the slowing of the flame propagation caused by the concentration increase of unburned gasoline. The main innovation is to solve the transient measurement of free radical distribution in unsteady premixed combustion by designing the timing control subsystem.