The collision behavior of binary droplets is widely present in natural phenomena and industrial applications such as raindrop formation, fuel spray, spray cooling, inkjet printing, pesticide spraying, etc. The collision result will be comprehensively affected by droplet parameters and gas phase environment. Research on the collision behavior and regulation mechanism of binary droplets has always been a hot spot in this field. Combining with the current experimental progress and numerical model of binary droplet collision, the main control factors and regulation mechanism of collision behavior will be reviewed. The influence of collision parameters, droplet physical and chemical properties, gas phase environment on the droplet collision behavior and control results is specifically introduced, and the development trend and direction of droplet collision theory and application are prospected.

Ecologicalization has become an inevitable choice for the sustainable development of process industrial parks. Based on the inherent characteristics of multi-elements, cross-media, multi-processes and multi-objective coordination in industrial parks, its ecologicalization process depends on the positive contributions from the research paradigms and methods of process systems engineering. Based on the introduction of the ecologicalization process and characteristics of industrial parks, this paper proposes a set of fundamental insights and needs for ensuring the sustainability. It focuses on the application of methods in process systems engineering to drive the sustainability of industrial parks. This paper systematically reviews sustainable performance analysis, energy conservation, water conservation, carbon management, mass integration, multi-networks integration, and informatization. The challenges and opportunities brought by the ecologicalization of industrial parks to the development of process systems engineering are proposed.

Chemical looping technology is currently one of the hotspots in energy technology research. Its key technologies include the preparation of carrier materials and the design of reactors. In this paper, application prospects of chemical looping were described. The design principles of chemical looping reactor were summarized. The chemical looping reactors reported in concepts, in building or in operation were reviewed. The purposes and design criteria were discussed. Flow patterns, reaction mechanisms and control characteristics during operation should be investigated in macroscopic reactor when using micro/nano-particles as looping materials. Hydrodynamic, mass transfer, heat and reaction coupling mechanism in reactor should be studied and reaction-to-reactor multi-scale model should be constructed. Fully scaled chemical looping reactor by self-heat balance should be tested. More attentions should be paid to the development of efficient carbon/ash stripper with aid of numerical simulation in the future.

In recent years, synthetic biology has emerged in many fields, and it has also played an increasingly important role in pesticide residue detection. Through synthetic biology, a variety of gene assemblies provide more potential for detection. The characteristics of simplicity, rapidity, durability, and low cost grow on its competence comparing with traditional detection methods. The support of miniaturized instruments also enhances its application value in situ detection of pesticide residues. But at the same time, the application of synthetic biology in pesticide residue detection is also affected by the complex detection environment and biological safety issues. This review mainly introduces the application and innovation of synthetic biology in the detection of organochlorine pesticides, organophosphorus pesticides, pyrethroid pesticides, and carbamate pesticides. Analyze its advantages and shortages and discuss its future development potential.

Semiconductor synthetic biology (also known as SemiSynBio, SSB) is an interdisciplinary subject that studies the synergy between semiconductor technology and synthetic biology. The living cell-semiconductor material hybrid system involved has a unique energy and signal transduction mechanism, which not only maintains the metabolic ability of living cells, but also retains the optoelectronic physical properties of semiconductor materials, and it has broad applications in the fields of chemical engineering, communication, computation, energy resource and medical treatment. This review outlines the state-of-the-art research advances of SSB in biocatalysis, intelligent biosensor and DNA data storage. In addition, forthcoming challenges and the corresponding solutions are also discussed. Overall, this review aims to provide valuable insights for advancing synthetic biology and semiconductor technology, two disciplines influencing chemistry engineering.

Ionic liquids (ILs) are a new type of green solvent, which have been widely used in the field of nanomaterial preparation as a solvent, template or structure directing agent due to their unique properties, such as low vapor pressure, wide liquid temperature range, non-flammability, chemical stability and tunable structure and properties. Nano-ZnO materials have a wide range of applications in the field of sensors, solar cells and photocatalysis. The research progress of ILs in the preparation of nano-ZnO materials in recent years is summarized. The applications of traditional aprotic ILs, protic ILs, basic ILs and poly(ionic liquid)s in the synthesis of nano-ZnO materials are compared and analyzed, as well as their roles in regulating the morphology, particle size and properties of nano-ZnO. And put forward suggestions for the future application of ILs in the preparation of metal nanomaterials.

As a kind of natural polyphenols, plant tannins are widely present in various tissues of plants. The structure of tannins are complex and diverse, and there are a large number of active groups such as phenolic hydroxyl groups, ester groups and ether groups, which can be combined with various substances to have the effects of anti-oxidation, ion adsorption and leather tanning. Plant tannins as a kind of functional material is widely used in pharmaceutical processing, food production, sewage treatment and other industries. However, natural plant tannins also have their inherent shortcomings, such as large molecular weight and poor fat solubility. Based on this, domestic and foreign scholars have been exploring the suitable tannin structure modification methods, so that this natural biomass resource can be more efficiently used in the industrial production. Based on the structure of tannin, this paper summarizes the structural modification methods of tannin in recent years and provides a reference for the high-value utilization of tannins.

1,6-Hexanediol is an important building-block chemical and applied widely in the synthesis of specialty chemicals and a variety of polymers, primarily in polyesters, polyurethanes and polyamides. Industrially, a most common route for 1,6-hexanediol production is catalytic hydrogenation of dimethyl adipate. Thermodynamic analysis and kinetic study are important links in the study of chemical process, but few reports have been reported on the dimethyl adipate hydrogenation. Hence, thermodynamic data of dimethyl adipate (DMA) and 1,6-hexanediol were calculated by group contribution method in this work, and the enthalpy, entropy, Gibbs free energy and equilibrium constant of reaction under different reaction conditions were calculated. As can be seen from the calculated results that the decreases of temperature and increases of pressure are beneficial to increasing the reaction equilibrium constant. Besides, kinetic study of DMA hydrogenation was preformed in the fixed bed tubular reactor. Experiments were carried out under the following conditions: temperature 473.15—514.15 K, pressure 2.0—6.1 MPa, LHSV 1.28—2.55 h^-1, molar ratio of H₂ to DMA 150—270. The exponential model was employed to describe the reaction rate and the obtained activation energy for dimethyl adipate hydrogenation was 63.55 kJ·mol^-1. The reaction order of dimethyl adipate and hydrogen are 0.63 and 0.40 respectively. The statistical test results show that the model can better describe the DMA hydrogenation reaction.

A multi-energy complementary energy supply system combined with energy storage was proposed, which effectively combined air source heat pump, water source heat pump, photovoltaic/thermal and energy storage technology (cold storage and heat storage) to achieve efficient and economic energy supply. The performance analysis and operation optimization of the energy supply system are carried out by using thermodynamic analysis method. First of all, the actual operation data of the energy supply system are collected through the energy monitoring platform, and the system performance is analyzed under the typical daily conditions in winter. The results show that the system is stable and its average COP and exergy efficiency are 2 and 32.24% respectively, which are higher than those of conventional system. Then, by analyzing the actual operating data of the system in winter, the operating rules of each energy storage condition were summarized, and the system optimization operating strategy was formulated. The heating cost per unit area of the system is only 12.5 CNY/m², and the annual unit exergy cost is 2.16 CNY / kWh. In addition, the dynamic payback period of this system is 3.66 a and 2.47 a respectively compared with the conventional air source heat pump direct supply system and gas-fired boiler heating system, which has obvious economic benefits.

Enhanced vapor injection refrigeration system has been widely used in the environmental control system of modern aircraft due to the advantages of high system efficiency and low operating cost. For the system designing and controlling, a dynamic simulation model of the enhanced vapor injection refrigeration system for aircraft is developed, and the experimental validation is performed. By abstracting the working principle of the compressor into three independent processes, an explicit calculation model of vapor-injected compressor based on physical theory is established; the dynamic models of the condenser and evaporator are developed based on moving-boundary method; and the solution algorithm of the system model is presented based on mass-guided method. Experimental validation results show that, the proposed model can well predict the dynamic trends of pressure and temperature responses; under the experiment conditions, the time-average deviations of the predicted system pressure and temperatures are 2.55% and -3.29℃, respectively.

Compared with the polymer-based aqueous biphasic systems (ABSs), the ionic liquid (IL)-based ABSs exhibited higher phase separation efficiency and stronger selectivity, and have attracted increasing attention in separation and purification. However, the kosmotropic components in the IL-based ABSs were inorganic salts or organic salts, which were adverse to maintain the stability and biological activity of the biomolecules in a strong alkaline solution. In this study, deep eutectic solvents (DESs) were used as alternative kosmotropic components to form novel ABSs with ILs (chaotropic components). The law of phase behavior at different temperature was investigated to screen out thermoreversible systems showing upper critical solution temperature (UCST) and lower critical solution temperature (LCST). Moreover, the physicochemical properties, such as the viscosity, density, conductivity, and pH of the IL-DES-water ternary systems as function of temperature were explored. Furthermore, quantum chemical calculations were used to analyze the interaction between the IL and water or DES and water. The research aims to reveal the mechanism of the thermoreversible IL-DES ABS and provide essential data for the desigin of a new ideal extraction system for the extraction of thermo-sensitive biomolecules.

The parallel flow heat pipe heat exchanger integrates the advantages of high efficiency heat exchange in the axial direction of the heat pipe and high efficiency heat exchange outside the parallel flow heat exchanger, and is a new type of heat pipe heat exchanger. In order to study the working mechanism and the flow process of the parallel flow heat pipe, a visualization experimental rig was set up, and the startup characteristic and the heat and mass transfer law of parallel flow heat pipe under different structural parameters, different heating powers and different working mediums were experimentally studied combined with high speed camera technology and infrared-ray test technology. The results show that the working mechanism of the parallel flow heat pipe is complicated. The gas column and the liquid column in the tube carry out the mutual oscillating flow due to the gravity and unbalanced pressure in the parallel multiple pipelines. Moreover, the flow patterns in the branch pipe are varied, including bubble flow, slug flow, annular flow and the like. At the same time, it is found that larger diameter and higher heating power will aggravate the oscillating flow between parallel pipelines, increase the disturbance of the working medium in the evaporation section and the condensation section, and enhance heat transfer performance of heat pipe.

The evaporation of the micro-liquid layer is an important heat exchange mechanism in the boiling process. This paper aims to investigate the heat transfer mechanism in boiling surface with an isolated bubble via the bubble dynamics observed in the boiling experiment. The single-bubble pool boiling was realized and the sequential images of the growth of the single bubble under different input heat fluxes were obtained first. The bubble sizes and radii of the root adhesive to the heating surface during the bubble period were further measured. Through the comparison between the measured bubble growth rate and the variation of bubble root radius, it is found that, the bubble growth rate is remarkably correlated with the variation of bubble root radius, whereas its correlation with the evolution of the macro-liquid layer region is relatively lower. This indicates that it is the evaporation of the micro-liquid layer underneath the growing bubble, rather than the macro-liquid layer at the vicinity of the bubble that plays a dominant role in the phase change process of single-bubble boiling. A numerical model of boiling heat transfer was established by matching the observed variation of bubble growth rates and measured temperatures of discrete points on the basis of micro-liquid layer evaporation. The heated surface was divided into three parts with different heat transfer mechanisms: dry area, micro-liquid layer region and natural convection region. Through multiple iterative computations for matching the measured data of bubble growth and the temperature underneath the heating surface, the micro-liquid layer thickness can be predicted as 3.43 μm when the surface superheat was 4.82 K. The predicted micro-liquid layer thickness is in a favorable agreement with the available references, which further confirms the dominant role of micro-liquid layer evaporation during the phase change of isolated-bubble boiling. This work provides theoretical basis for the future numerical simulation of isolated-bubble boiling heat transfer.

The study uses PTFE nanoparticle coatings to construct a super-hydrophobic surface and a striped pattern mixed wettable surface on a 50 mm×100 mm copper-based surface. In order to explore the influence of the inclination angle of the stripes on the condensation heat transfer, a mixed wettable surface with stripes and the width direction of the copper plate at 90° and 60° was used in the experiment. Besides, the width of the hydrophilic region and superhydrophobic region were both set to 1 mm, and the proportion of hydrophilic area were 48.8% and 48.7% respectively corresponding to the above-mentioned hybrid wettable surfaces. The condensation phenomena were recorded by a high-speed camera (Phantom, Miro Ex4). Dropwise condensation (DWC) was achieved on the super hydrophobic surface and superhydrophobic region of the hybrid wettable surfaces, while filmwise condensation (FWC) was observed on the hydrophilic region of the hybrid wettable surfaces. The result of the experiment indicated that the condensation heat transfer coefficient (HTC) of the super hydrophobic surface and the hybrid wettable surfaces has a strong correlation with the droplet departure rate and surface renewal. The faster the droplet departure rate is, the higher the condensation heat transfer coefficient will be. Moreover, due to the coarse textures of the superhydrophobic surface, the wetting model of droplets formed on the superhydrophobic surface tended to represent the Wenzel wetting model. As a result, the droplet departure rate and HTC of the superhydrophobic surface was lower than FWC when the condensation heat transfer temperature difference \mathrm{\Delta }{T}_{\mathrm{s}\mathrm{u}\mathrm{b}} was in the range of 0—20 K. However, the hybrid wettable surfaces were able to enhance the HTC of the superhydrophobic surface by increasing condensation surface renewal owing to the liquid bridge departure. The highest HTC of 16.64 \mathrm{k}\mathrm{W}/({\mathrm{m}}^{\mathrm{2}}?\mathrm{K}) and condensation heat flux of 188 \mathrm{k}\mathrm{W}/{\mathrm{m}}^{\mathrm{2}} when \mathrm{\Delta }{T}_{\mathrm{s}\mathrm{u}\mathrm{b}} was 11.3 K were observed on the hybrid wettable surface (60°-parallel-stripes pattern), whose HTC was 2.14-fold compared with that of the superhydrophobic surface. While an HTC of 13.63 \mathrm{k}\mathrm{W}/({\mathrm{m}}^{\mathrm{2}}?\mathrm{K}) which was 1.68-fold compared with that of the superhydrophobic surface was observed on the hybrid wettable surface (90°-parallel-stripes pattern) when \mathrm{\Delta }{T}_{\mathrm{s}\mathrm{u}\mathrm{b}} was 13.8 K.

Research on the heat transfer of borehole heat exchanger (BHE) is the key to enhance the heat transfer efficiency of the ground source heat pump(GSHP) system. Most of the BHE models proposed in the current literature ignore the influence of thermal dispersion, which is caused by spatial heterogeneity of underground aquifer. In order to consider thermal dispersion effect, an improved full-scale heat transfer model is developed by including thermal dispersion coefficient. The main findings are summarized as follows. The appropriate range of seepage velocity applied in the model is from 1×10^-8 m/s to 1×10^-6 m/s. The thermal dispersion effect is mainly reflected in the medium and long time scale. Seepage velocity, thermal dispersivity and porosity are the main factors affecting the heat transfer process. High values of the seepage velocity and thermal dispersivity of groundwater, as well as low values of the porosity, may lead to strong thermal dispersion effect. Seepage velocity has the strongest impact on the overall heat transfer around boreholes, followed by the thermal dispersivity, and the porosity has the weakest effect. As far as the borehole group is concerned, thermal dispersion has the greatest impact on the heat transfer process of the upstream borehole, followed by the middle reaches, and the downstream is the least. Within the parameters studied in this paper, thermal dispersion can increase the steady-state heat transfer capacity of the borehole by 5.52% to 49.93%.

Based on double film theory and boundary layer theory, mathematical models of gas and liquid film thickness and heat transfer coefficient of round tube, elliptical tube and drop tube are established. The model is verified based on the heat transfer coefficient of the round tube. The average deviation between the calculated result and the experimental value is about 6%, which basically meets the actual requirements of the project. Under the given conditions, distribution law of gas and liquid film thickness and heat transfer characteristics are obtained by calculating the heat transfer coefficient of each tube type under different curvature. The results show that: when the effective heat transfer area is the same, gas and liquid film thickness and heat transfer coefficient of the three types of tubes increase with the increase of curvature at a certain angle; when curvature is the same, the heat transfer coefficient of elliptical tube is the largest and that of circular tube is the smallest. At the same time, influence mechanism and separation mechanism of different tube shape and curvature on gas and liquid membrane discharge were analyzed. It provides some theoretical guidance for heat transfer enhancement.

The super-hydrophobic surface structure parameters will affect the droplet condensation heat transfer performance, droplet growth and distribution. The departure radius of droplets on the vertical wall during steam condensation with non-condensable gas was determined by the force balance, and a heat transfer model for dropwise condensation with non-condensable gas was developed. The influence of the space between the micro-pillars on superhydrophobic surface on dropwise condensation heat transfer performance was conducted under various non-condensable gas concentrations and surface subcoolings. The optimum value of the micro-pillars spacing which can induce the maximum dropwise condensation heat transfer performance was developed. Furthermore, the effects of non-condensable gas concentration and surface subcooling on the optimum micro-pillars spacing were analyzed. The results illustrated that the optimum micro-pillars spacing ascended with the increase of the non-condensable gas concentration when the concentration of non-condensable gas was lower than 20%. However, the optimum micro-pillars spacing decreased with the increase of the non-condensable gas concentration when the non-condensable gas concentration was higher than 20% within the applied surface subcooling. The results supplied the primary information for optimizing the micro-nano structures of superhydrophobic surfaces which can induce the condensation heat transfer enhancement of steam in the presence of non-condensable gas.

NH₃ selective catalytic reduction (NH₃-SCR) can effectively remove nitrogen oxides (NO_x) from automobile exhaust. The development of low-cost catalysts with high activity at medium and low temperatures and environmentally friendly is the key to this technology. In this work, by utilizing cheap commercial organic structure guide agent morpholine as template, and copper amine complex (Cu-TEPA) as both Cu source and co-templating agent, a low-cost Cu-SAPO-34 molecular sieve was prepared by one-step hydrothermal synthesis method. It was found that with increasing the Si content, the crystallinity of Cu-SAPO-34 gradually decreases, and the acidic sites and Cu²⁺ ions gradually decrease. The NH₃-SCR performance of Cu-SAPO-34 with three different Si contents under different space velocities was systematically studied through fixed-bed experiments. The results show that under gas volumetric space velocity (GHSV=40000—120000 h^-1), Cu-SAPO-34 shows excellent SCR activity; when the SiO₂/Al₂O₃ molar ratio is 0.2, the prepared SCR catalyst, Cu-SAPO-34 has ideal low-temperature activity with the conversion of more than 90% and wide temperature window (225—425℃). This is attributed to the increase of Si addition, the crystallinity of Cu-SAPO-34 gradually decreases, and the precipitation of acidic sites and Cu²⁺ ions gradually decrease.

In the process of wet leaching of pyrolusite, the traditional stirring blade reactor is prone to fluid “swirling”, which leads to poor mass transfer effects and lower reaction efficiency. In this paper, rigid-flexible combined impeller was applied to reduction leaching process of pyrolusite to enhance manganese ore leaching efficiency. The results show that under the condition of pyrite-to-pyrolusite mass ratio is 0.20, the sulfuric acid concentration is 1.5 mol/L, the liquid-to-solid mass ratio is 10, and the temperature is 363 K, the leaching rate of manganese in pyrolusite reaches 90.12%, which is 5.5% higher than that of traditional impeller. Simultaneously, it is also found that the leaching process follows the shrinking core model and is controlled by the surface chemical reaction. The reaction orders of pyrite-to-pyrolusite mass ratio, sulfuric acid concentration and liquid-to-solid ratio are 1.2679, 0.4182 and 1.1959, respectively, and kinetic equation is 1- (1-X)^1/3=0.96×10³(m_{\mathrm{F}\mathrm{e}{\mathrm{S}}_{\mathrm{2}}}/m_{\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{2}}})^1.2679×[H₂SO₄]^0.4182(L/S)^1.1959exp(-41.75×10³/RT)t, the apparent activation energy of the leaching process is 41.75 kJ /mol. The apparent activation energy of pyrolusite leaching reaction in rigid-flexible combined impeller system is 4.515—20.54 kJ/mol lower than that in regular agitation system.

Selective catalytic reduction (SCR) technology is widely used in flue gas nitrogen oxide emission control due to its high denitration efficiency and good selectivity; however, currently widely used vanadium titanium SCR catalyst can oxidize SO₂ in flue gas into SO₃, and excessive SO₃ in flue gas will cause serious impact on the safe operation of power plant and also cause environmental pollution. Taking commercial V₂O₅-WO₃/TiO₂ catalyst as the research object, the effects of flue gas flowrate, temperature, O₂ concentration and SO₂ concentration on the formation of SO₃ on the catalyst during SCR denitrification were systematically studied, and the reaction kinetics of SO₃ formation was further discussed. The results show that the reaction order of SO₂ is 0.59. When the concentration of O₂ is more than 3%, the reaction order of O₂ is 0, and the activation energy of SO₃ formation on catalyst is 70.39 kJ/mol. The increase of SO₂ concentration will increase the reaction rate of SO₃ formation; O₂ concentration has no significant effect on the formation of SO₃ on the catalyst. The temperature of flue gas has a significant effect on the formation of SO₃, and high temperature can promote the formation of SO₃.

Gasification is one of the effective ways for high-value utilization of coal, biomass and other carbon-containing fuels. To investigate the reaction characteristics of tar during gasification, naphthalene was selected as the tar model compound and converted in a micro fluidized bed by using fluid catalytic cracking (FCC) catalyst and lignite coke as contact cracking carrier. The cracking kinetics of naphthalene in terms of CH₄ and H₂ generation were calculated by Friedman method and integral method respectively. The results show that both FCC catalyst and lignite coke had obvious catalytic effect on naphthalene. When lignite coke was used for naphthalene cracking, the overall reaction activation energy was lower than that of FCC catalyst. The catalytic cracking of naphthalene over FCC catalyst was close to three-dimensional diffusion (spherical symmetry) and nucleation and growth (n=2/3) models, while the three-dimensional diffusion (cylindrical symmetry) and contraction geometry (cylindrical symmetry) models had a good fitting degree for naphthalene cracking using lignite coke.

Hollow ZSM-5 zeolites with different Si/Al molar ratios and hierarchical porous shell were fabricated via employing dissolution-recrystallization strategy, and utilized as support to load precious Pt (Pt/HZ-x) for hydrodeoxygenation of guaiacol to cycloalkanes. The physicochemical properties of the as-synthesized catalysts were characterized by powder X-ray crystalline diffraction (XRD), field emission scanning electron microscope (SEM), field emission transmission electron microscope (TEM), nitrogen adsorption and desorption (N₂-BET), ammonia temperature program desorption (NH₃-TPD) and X-ray photoelectron energy spectroscopy (XPS). Benefit from the special hollow structure, hollow ZSM-5 zeolites exhibited a larger external specific surface area and mesoporous volume, which was favorable to promote the dispersion of metallic Pt and mass transfer of reactants. The Pt/HZ-x catalysts showed excellent catalytic performance and hydrodeoxygenation activity for guaiacol, and could reach 100% selectivity to cycloalkanes at a low temperature of 220℃. In addition, as the acidity of the molecular sieve carrier weakens, the degree of secondary reaction of the guaiacol hydrodeoxygenation product decreases, which increased the selectivity to cyclohexane.

The Pt-Ni bimetallic catalyst supported on the graded pore ZSM-5 zeolite was prepared by the equal volume co-impregnation method, and the effect of different Pt/Ni ratios on hydrodeoxygenation performance of guaiacol and dibenzofuran was systematically studied. The physicochemical properties of the as-synthesized Pt-Ni catalysts were characterized via XRD, N₂-BET, SEM, TEM and H₂-TPR. The results showed that when the loading amount of Ni was small (1% and 3%,mass ratio), it was beneficial to promote the dispersion of active metals and enhance synergistic effect between Pt-Ni bimetals. However, the active metals would agglomerate with the increase of Ni loading to 5%(mass). Compared with the Pt/HZ-75 catalyst, all the Pt-Ni/ZSM-5 catalysts exhibited excellent hydrodeoxygenation catalytic activity, and the introduction of Ni significantly improved the conversion rate and enhanced the selectivity to bicyclohexane. Furthermore, with the decrease of Pt/Ni ratio in Pt-Ni/ZSM-5 catalyst, the catalytic activity of Pt-Ni catalysts gradually increased, while the selectivity to bicyclohexane first increased and then decreased. The Pt-3Ni/HZ-75 catalyst showed the best catalytic activity and bicyclohexane selectivity at 3 MPa and 260℃. After 4 h of reaction, the conversion rate reached 100% and the bicyclohexane selectivity reached 43%.

In the H₂O₂/acetonitrile system, MgO prepared by precipitation method was used as a catalyst to catalyze the Baeyer-Villiger (B-V) oxidation of cyclohexanone to synthesize ε-caprolactone. The effect of the preparation conditions and reaction conditions on the conversion to cyclohexanone and the yield to ε-caprolactone were discussed. According to the experimental results, Mg(NO₃)₂·6H₂O was used as the precursor, and the best oxidation performance was obtained when the calcination temperature was 600℃ and the calcination time was 2 h. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used. The analysis results show that the MgO particle increases from 9.53 nm to 29.49 nm when the temperature is in the range of 500℃ to 800℃. In n(catalyst)∶n(cyclohexanone) = 0.45∶1, n(acetonitrile)∶n(cyclohexanone) = 12∶1, n(hydrogen peroxide)∶ n(cyclohexanone) = 10∶1, 70℃, 6 h, the conversion rate of cyclohexanone was 95.2% and the yield of ε-caprolactone was 83.1%. The mechanism of hydrogen peroxide B-V oxidation of cyclohexanone was studied in-depth, and the reaction was analyzed in real time by online in-situ infrared spectroscopy. The peroxyacetal reaction path was verified.

The hydrogenation of CO₂ on iron-based catalysts to produce light olefins is an effective way to realize the high-value utilization of C1 resources. To improve the selectivity of low-carbon olefins, Fe-MOF is used as the main body and terephthalic acid is used as the framework ligand to construct an iron-cobalt bimetallic catalyst (FeCo/MC) with a controllable metal ratio, which clarifies the synergistic effect of the bimetal and the effect of metal ratio on hydrogenation performance. It was found that the addition of Co can increase the basic sites on the catalyst surface to improve CO₂ adsorption significantly, while it promoted the carbonization of iron and benefited the positive progress of the reverse water gas shift reaction (RWGS) through the CO consumption of the Fischer-Tropsch reaction(FTS) route. In addition, a suitable iron to cobalt ratio helped to improve the intermetallic intimacy, which can connect active sites reasonably and obtain the best light olefin selectivity and the CH₄ selectivity as low as possible. The iron to cobalt ratio of 6 showed the highest light olefins selectivity (37.14%), and the CO₂ conversion rate was 32.72%.

With trimethylphosphine (TMP) as the precursor, ZSM-5 was firstly modified to improve its hydrothermal stability, and then subject to impregnation of Ga₂O₃ or ZnO to prepared phosphorus and metal oxide modified ZSM-5 zeolites. The statuses of metal oxides and phosphorus species, as well as ZSM-5 matrix and their interaction were systematically investigated by XRD, MAS NMR, NH₃-TPD and Py-FTIR spectroscopy. The cleavage of n-tetradecane was used as a probe reaction to study the effect of phosphorus and metal oxide compound modification on the catalytic cracking performance of ZSM-5. Via such trimethylphosphine and metal oxide modification, more acids were preserved to show better cracking performance, as well as higher light olefin yield and selectivity with lower coke yield.

In order to explore the changing law and influencing factors of the filtering performance of natural gas filter elements under high pressure conditions, four types of filter elements were selected as the research objects, and field tests and laboratory performance tests were carried out. The evaluation was carried out in turn according to the technical standards, including the field test for about 410 d, the laboratory test before and after the field test, and the performance test on filter layers. It was found that after the field test, the pressure drop in filter cartridges increased by about 20%, and the rise rate of pressure drop increased even more under the same experiment condition of gas-solid filtration, while the relative difference of the filtration efficiency and quality factor decreased between the four types of filter cartridges. The filter layers were compressed by 7%—31% under the high-pressure condition. As particles were embedded or deposited at the filter media, the permeability of each filter layer generally decreased while the tensile strength of the material increased. Besides, some methods were shown to benefit the stable and reliable operation of the filter cartridge under high pressure conditions, including the selection of fiber material with uniform pore size distribution, composite material with cascade design of filtration accuracy, pleating of filtration layers and inlet side skeleton with pre-separation and diversion functions. The research provides a guidance for the development and optimization of separation cartridges suitable for high-pressure natural gas transportation.

To explore the cluster distribution and evolution during the process of adsorption at solid-vapor interface, a series of experimental measurements and theoretical analysis are hybrid to study the characteristics of water vapor adsorption on silica and graphite surfaces. The adsorption isotherms in the full pressure range are obtained based on the Zeta adsorption model, the cluster distributions at different pressure ratios are obtained, the critical conditions for the adsorption phase change and wetting are determined. The results showed that Zeta adsorption isotherm has no singularity at saturation pressure. The adsorption measurements are in good agreement with the theoretical prediction by Zeta adsorption model. Meanwhile, the vapor adsorbate is formed as clusters with different number of molecules. In the low pressure ratio zone, small molecular clusters and zero adsorption units dominate the adsorption site. As the pressure ratio increases, the types of adsorption clusters increase. Once the pressure exceeds a certain value, the entropy reaches a maximum value, indicating the occurrence of phase transition at the interface. The surface tension of graphite and silica and the critical conditions of interfacial wetting under the condition of zero adsorption are determined. Under the wetting pressure ratio, homogeneous macromolecular clusters gather to form a liquid-film-like wetting interface.

Radon (Rn) which exists in building materials has become an important radioactive gas that can pollute indoor air and can cause serious harm to human health. Therefore, it is urgent to develop new porous materials with high-performance to selectively adsorb Rn. Based on the grand canonical ensemble Monte Carlo simulation method (GCMC), the adsorption and separation performance of 163 zirconium-based metal organic frameworks (Zr-MOF) for Rn/N₂ and Rn/O₂ mixtures under room temperature and pressure were systematically studied. The results showed that Zr-MOF materials exhibited excellent adsorption and separation performance of Rn, when their pore size is in the range of 5.6—8 ? and accessible surface area is in the range of 140—870 m²/g. In addition, it was also found that the introduction of strong polar functional groups, such as —COOH and —SO₃H on the framework could dramatically enhance the separation performance of materials for Rn/N₂ and Rn/O₂ mixtures. These results can provide a theoretical reference for the future rational design and controllable synthesis of high-performance MOF separation materials.

In this work, a novel strategy of “highly volatile molecules synergistic desorption” was proposed, in which hydrogen bonds between highly volatile ethanol molecules and low volatile flavor vanillin molecules played an important role in enhancing the desorption efficiency of vanillin molecules over MIL-100(Fe) in the vanillin/ethanol MIL-100(Fe) co-adsorption system. The existence of a hydrogen bond between vanillin and ethanol was determined by molecular simulation. Similarly, the effect of binding energy between vanillin and ethanol in MIL-100(Fe) was also studied. The results showed that MIL-100(Fe) exhibited a high adsorption capacity (780 mg/g) for vanillin ethanol solution. After drying and pretreatment at 60℃, the desorption efficiency of vanillin over MIL-100(Fe) was significantly increased and the desorption peak temperature was found to be 190℃. Meanwhile, the effect of different vanillin adsorption amount on vanillin desorption rates over MIL-100(Fe) was also investigated. Consequently, the vanillin desorption rate increased first and then decreased with an increase in vanillin adsorption, reaching a maximum desorption rate of 59.1% when the adsorption amount was about 606 mg/g. Finally, the strong hydrogen bonding between vanillin and ethanol was found by molecular simulation calculation, and the binding energy between vanillin and MIL-100(Fe) decreased from -103.47 kJ/mol to -66.58 kJ/mol in the presence of ethanol, which made it easier for vanillin molecules to be desorbed from MIL-100(Fe).

Rotary vibrating screen is widely used in the classification of powders and colloids in various industries. The exciting force of single motor rotary vibrating screen does not pass through the mass center of vibrating body, so that the vibration system moves in a circular motion and a conical pendulum around the center of mass. This kind of movement makes the vertical amplitude on the screen surface uneven, and there are problems such as granular materials diffuse quickly to the periphery of the screen surface, the material layer is thick, the screening efficiency is low, and the particle uniformity is poor. Therefore, a rotary vibrating screen with the principle of balanced motion was proposed. Through DEM numerical simulation, the material movement law on the screen surface, particle size distribution and particle velocity of the rotary vibrating screen under normal motion were intuitively compared with which under balanced motion from the perspective of screening efficiency. The results show that the material rotates and diffuses more evenly around the screen surface under balanced movement, and the material layer is thinner, which can effectively improve the solid-phase screening efficiency of the rotary vibrating screen and the uniformity of the screening particles. It can better solve the relatively difficult problem of particle penetration when the ratio of particle size to sieve aperture is between 0.7 and 1.0.

Acetylene hydrogenation reactor is an important device for removing small amounts of acetylene in high-concentration ethylene streams in the ethylene industry. The device generally runs for a long time, during which the catalyst activity in the reactor gradually decreases until the activity cannot meet the process requirements. The full cycle operation optimization of acetylene hydrogenation reactor should be carried out rigidly according to the operation optimization scheme within the operation cycle. However, in the actual industrial process, in order to meet the temporary process scheduling requirements, the operation plan of acetylene hydrogenation reactor needs to be temporarily changed in the remaining operation cycle after running in accordance with the operation optimization plan for a certain time, which brings more changes and challenges to the operation optimization problem. Based on margin estimation and control optimization framework of slow time varying systems, the full cycle dynamic optimization problem of temporarily changing the operation optimization scheme during the operation cycle is studied in this paper. The ways to change the operation optimization scheme include: changing operation cycle and pursuing economic benefit maximization, and changing optimization objective and pursuing operation cycle maximization.Through the analysis of these two optimization schemes for changing operation, it is found that the closer the operating cycle of the former is to the original operating cycle, the higher the total economic benefit of the whole cycle. The earlier the switching time of the latter, the longer the operating cycle that the reactor can maintain. However, the full-cycle economic benefits of both are inferior to the original operation optimization plan, and temporary process scheduling is generally unfavorable to the full-cycle optimized operation of the acetylene hydrogenation reactor.

In order to improve the prediction accuracy of the entrained-bed gasifier's outlet results under the conditions of coal type changes and process parameter fluctuations, a mechanism model, a generalized regression neural network (GRNN) model and a hybrid model are used to model the gasifier. The hybrid model constructed by GRNN model and mechanism model, combined with two different coal samples to analyze the prediction results of the three models. The results show that the three models can simulate the gasification process well. The prediction errors of the hybrid model regarding gasification temperature and the contents of CO, CO₂ and H₂ are 0.18% and 0.25%, 1.72% and 0.43% when the coal type is fixed. Compared with the mechanism model and the GRNN model, the error of hybrid model is smaller. When the coal type is changed, the prediction of the outlet gas result of the hybird model is the closest to the actual production data, and the error is 0.81% and 0.11%, 2.53% and 0.42% respectively. It is proved that the hybrid model can effectively simulate the gasification process under the conditions of coal type changes and process parameter fluctuations, which greatly improves the prediction accuracy of the mechanism model and the GRNN model.

The process simulation software HYSYS was used to simulate the whole process of a 650000 t/a heavy oil catalytic cracking unit in a refinery. An improved non-dominated sorting genetic algorithm (NSGA-Ⅱ) was used for the multi-objective optimization of the FCC separation system, with the maximum yield of target products (gasoline + LPG) and minimum energy consumption of separation system as the optimization objectives. A meticulous multi-objective optimization method was established through the optimal selection of decision variables, the study of optimal algorithm parameters (including population, P_c, P_m adaptive strategy, and generation), and the optimal decision. The optimization results showed that the yield of the target products (gasoline + LPG) increased by 4.32 percentage points and the energy consumption of the separation system decreased by 16.88%. The optimization results provided important data support and optimization suggestions for the optimization of the operating variables of the FCC separation system.

Accurate prediction of effluent total phosphorus is essential for the stable and efficient operation of urban wastewater treatment plants. Aiming at the problem that effluent total phosphorus is difficult to predict in urban wastewater treatment process, a prediction method of effluent total phosphorus based on modified ensemble empirical mode decomposition(MEEMD) and deep belief network (DBN) is proposed in this paper. First, a MEEMD algorithm is designed to decompose the effluent total phosphorus data signal of the effluent from urban wastewater treatment process. Then, establish a deep belief network prediction model based on simulated annealing (SA) algorithm, and effectively predict each IMF component obtained after decomposition through the optimized model structure. Finally, the effectiveness of the proposed method is verified by the prediction of atmospheric CO₂ concentration and the effluent total phosphorus in urban wastewater treatment.

The current international standards for the SIL rating of safety interlocking circuits are only for a single scenario and cannot consider the impact of risk coupling between multiple associated scenarios. When designing the risk distribution and reduction plan of multiple overpressure protection SIF circuits for large-scale combined equipment, it is necessary to consider the risk of flare system overload when the initial event causes multiple devices to discharge at the same time. Based on the situation, the traditional LOPA grading method of the protective layer is improved by the simultaneous discharge superposition method of multiple discharge sources, and a quantitative load calculation method is proposed to determine the safety integrity level of multiple overpressure interlocking protection circuits that affect each other: Reversely realize the check of the safety integrity level of the upstream overpressure interlock by the quantitative data and allowable risk level of the associated release risk of flare system. The case shows that by calculating the frequency of an overpressure accident of the flare system during a power outage, the safety integrity level of multiple overpressure interlocking protection SIF circuits coupled with risk can be recalculated, thereby completing the correction of the traditional LOPA rating results.

Using hydrated salt K₂CO₃·1.5H₂O and expanded graphite (EG) as chemical heat storage materials and porous matrix respectively, a composite heat storage adsorbent K₂CO₃@EG was developed. The desorption, adsorption performance and cycle stability of the composite sorbent and pure salt without EG-doping were compared and analyzed. The results show that the desorption temperature of the composite adsorbent is reduced, and the adsorption kinetics of adsorbate is obviously improved, which can effectively avoid deliquescence. After fifteen consecutive desorption-hydration cycle experiments, the heat storage density of pure salt and composite adsorbent decreased by 27.6% and 10.9%, respectively. In addition, the numerical results of the thermal storage unit preliminarily verify the feasibility of the thermal storage system.

Waste incineration power plants have large fluctuations in the calorific value of waste entering the furnace, which affects the stability of boiler operation and power generation efficiency. The use of image deep learning methods to achieve real-time prediction of the heat value of waste entering the furnace will help the power plant achieve "advanced regulation". Currently, there is lack of waste image database coinciding with waste composition in China after reviewing researches of image recognition and calorific value prediction progress of waste. Yolov5 is adopted for waste image detection and calorific value prediction. Furthermore, industrial cameras are used to real time capture images of waste before entering the furnace, and the image database of waste would be built by waste classifying annotation. Following this, we envisage a calorific value prediction model based on the obtained data being trained through using mosaic enhancement and neural network. In the future, it is meaningful to combine deep image learning with image recognition technology for waste calorific value prediction, which will be higher precision and faster response time.

Carrier material is the foundation for the construction of immobilized system, in which the pore structure directly affects the immobilized biomass and the degradation results. In this study, different pore sizes of polyurethane foam were synthesized and were used to immobilize Alcaligenes sp. DN25 for phenol degradation. The results showed that the biomass on the polyurethane foam with pore network structure reached the maximum value of (0.0253±0.0010) g when the pore size was 150 μm. Phenol of 1160 mg·L^-1 was completely degraded by the PUF-immobilized cells within 48 h, while the freely suspended cells were completely inhibited. It was found that the equilibrium adsorption rate of 900 mg·L^-1 phenol by the PUF carrier was 56.1% within 12 h. Furthermore, phenol degradation by the PUF-immobilized cells under the conditions of initial pH at 6.0—9.0 and NaCl concentration of 0—4.0% were investigated, respectively. There were not significant differences in phenol degradation under the conditions of initial pH and NaCl concentrations. In addition, the removal rate of 500 mg·L^-1 phenol can still be maintained at 100% after the repeated use of 11 batches of immobilized cells, reflecting the enhancement of the PUF-immobilized cell system on both the phenol treatment concentration and system stability.

Analysis on the flame characteristics of ethanol counter flame combustion is the key to understand the formation of diffusion flame and guide the design of ethanol counter flame burners. The combustion characteristics of the diffusion flame of ethanol diluted with air and nitrogen are simulated by using the counter flame diffusion flame model combined with the optical thin radiation model, and the influences of ethanol concentration and strain rate on the flame structure, temperature distribution and temperature sensitivity of the peak temperature location are discussed. The results show that with the increase of ethanol concentration, the CO and H₂ reaction zone moves to the fuel side, the flame area becomes wider, the peak flame temperature gradually increases, and the rising trend gradually slows down, and the influence of intermediate products and CO on temperature sensitivity decreases. With the increase of strain rate, free radicals and CO increase, intermediate products decrease, component distribution area and flame area become narrower, flame temperature peak gradually decreases, and the influence of intermediate products and CO on temperature sensitivity gradually increases.

In situ infrared spectroscopy was used to systematically study the electro-oxidation reaction information of p-toluenesulfonic acid (p-TSA) on the titanium-based lead dioxide (Ti/PbO₂) electrode. The results of cyclic voltammentry curve indicated that Ti/PbO₂ electrode exhibited a high electrochemical activity for the oxidation of p-TSA, and the direct oxidation potential ranged from 0.55—0.9 V. When the voltage was less than 1000 mV (vs. SCE), the multi-step potential FTIRS (MSFTIRS) and time-resolved FTIRS (TRFTIRS) analysis showed that the p-TSA was in the process of breaking of sulfonic acid group and methyl group oxidation of side-chain of benzene ring . When the voltage was higher than 1000 mV (vs. SCE), the aromatic ring of p-TSA was degradated. Meanwhile, the compounds of acid, alcohol and ketone were generated. The results of the reaction kinetics study showed that the apparent rate constant K of p-TSA electrooxidation has a linear relationship with the current density j, the removal of chemical oxygen demand (COD) increased with the increase of specific charge, and the average current efficiency showed a downward trend.

Fluorine is one of the essential trace elements in human life activities, but excessive intake of fluorine will cause fluorosis such as dental fluorosis and skeletal deformation. In this paper, the Al₂O₃/AC composite material was obtained through simple sonication of activated carbon (AC) and Al₂O₃ nanoparticle. Field emission scanning electron microscopy proved that Al₂O₃ was successfully loaded on the AC surface with a uniform distribution at the doping amount of Al₂O₃ of 5%. The results of N₂ adsorption-desorption test showed that the specific surface area of the Al₂O₃/AC composite increased. Cyclic voltammetry, constant current charge discharge and electrochemical impedance measurements demonstrated the improvement of ionic conductivity and specific capacitance of the composite after Al₂O₃ doping. Effect of Al₂O₃ doping amount was investigated and the 5% Al₂O₃/AC electrode achieved the optimal capacity of 92 F·g^-1 in 7 mmol·L^-1 NaF solution, better than that on AC electrode (62 F·g^-1). When being applied as the anode in capacitive deionization device, the Al₂O₃/AC electrode exhibited a defluorination capacity of 234 μmol·g^-1, much higher than that on AC electrode (115 μmol·g^-1). In addition, the 3-cell CDI stack delivered a 80% removal of F^- in the simulated groundwater containing F^-, Cl^- and SO₄^2-, while only 25% of Cl^- and 56% of SO₄^2- were removed. It demonstrated the excellent selective defluorination performance. The adsorption amount of F^- retained 81% after 10 adsorption/desorption cycles. The electrode material is simple to prepare and has good defluorination selectivity. It is expected to be used in the purification and defluorination of groundwater in high-fluorine areas in the CDI process.

Two types of lignin activated carbon with different structures were prepared from kraft lignin using phosphoric acid activation or mixed acid consisting of phosphoric acid and sulfuric acid as activating agents, respectively. The activated carbon was characterized by scanning electron microscope (SEM), infrared spectrum (FTIR), nitrogen adsorption and desorption, elemental analysis and Boehm acid value titration. The prepared activated carbon was applied to the adsorption of methylene blue (MB) dye wastewater. The results showed that the specific surface area, total pore volume, mesoporous volume and oxygen content of the carbon activated by mixed acid were 27.9%, 26.4%, 29.3% and 29.2% higher than those of the carbon activated by phosphoric acid alone, respectively, and distribution becomes more concentrated. Thus, the carbon activated by mixed acid has excellent adsorption performance for methylene blue in the range of pH 2—9, and the maximum saturated adsorption capacity reaches 1118.90 mg·g^-1, which is 20.3% higher than that of the carbon activated by phosphoric acid, showing good adsorption performance. The adsorption rate is fast, the adsorption process follows Langmuir adsorption isotherm and the pseudo-second-order kinetic equation, and the intra-particle diffusion is not the only decisive step.

Epoxysilicone oil (ETSO) was synthesized with (3-glycidoxypropyl)-1,1,3,3- tetramethyldisiloxane (EDH) and octamethylcyclotetrasiloxane (D4) as raw material first. Then intermediate organosilicone block silicone oil (PTSO) was obtained by amination with meglumine. Finally, Bola silicone quaternary ammonium salt (BPTSO) was synthesized by quaternization of PTSO and γ-chloropropyltrimethoxysilane (CPTSO). The process conditions of BPTSO were optimized as follows: the reaction temperature was 80℃, the molar ratio of material was n(PTSO)∶n(CPTSO)=1∶1.2, the reaction time was 3 h, and the conversion rate of PTSO was 98.60%. The structure and morphology of BPTSO were characterized by FT-IR, ¹H NMR, TGA, SEM and TEM. The results of performance test show that BPTSO have core-shell structure and superior stability, the fabrics treated with BPTSO emulsion had excellent softness, whiteness and hydrophilicity. The depth enhancement rate of cotton fabric reached 46.5%.

The rice grain-like FeS₂/C nanomaterial with core-shell structure was prepared by anion displacement reaction. The prepared composite shows enhanced inoic and electronic conductivity, excellent electrolyte infiltration characteristics, and capability of buffering the volume change. When evaluated as anode of lithium ion batteries, the FeS₂/C electrodes exhibit high reversible capacity of 1100 mA·h·g^-1 at 100 mA·g^-1 and outstanding rate capability. Even at high current density of 2 A·g^-1, a reversible capacity of 866 mA·h·g^-1 can be achieved. The results in this paper provide new ideas and methods for the preparation of other core-shell materials.

Nanomaterials could improve the heat transfer and thermal heat storage performance of molten salts and further increase the efficiency of heat transfer and thermal heat storage systems greatly. To find efficient method for large-scale production of molten salt nanofluids, both the high-temperature melting method and the aqueous solution method were employed to prepare molten salt nanofluids by adding SiO₂ nanoparticles to a binary nitrate salt. Then, methods of differential scanning calorimetry, thermogravimetric analysis and micromorphology analysis were used to investigate the enhancement of latent heat and sensible heat, change of micromorphology of molten salt nanofluids prepared by the two methods. Results show that molten salt nanofluids with optimal performance were observed under the mixing time of 90 minutes for both preparation methods when heat of fusion and specific heat of molten salt nanofluid prepared by the high-temperature melting method are 2.6% and 28.18% higher than those by the aqueous solution method; Effect of preparation methods on melting point is weak but is apparent on micromorphology of molten salt nanofluids. Formation process and structure of cloud nuclei determine the thermal storage performance of molten salt nanofluids. In addition, preparation process of the high-temperature melting method is simple and energy-saving, which is suitable for large-scale production and engineering application of molten salt nanofluids.

Hierarchically porous carbons have shown great potential in the fields of electrochemical energy storage. The template strategy coupled with activation technique is considered as one of the most effective ways to produce hierarchically porous carbon. However, this method uses strong acids and strong bases, causing pollution to the environment. Therefore, it is urgent to develop an acid-free and base-free technique to prepare hierarchically porous carbons. Herein, nitrogen doped hierarchically porous carbon nanosheets (NHCNs) are synthesized from cal tar pitch by using the mixture salt of NaCl and Na₂CO₃ as template coupled with K₂CO₃ activation. The templates and activators can be removed by water washing without the use of strong acids and bases, and this work provides an acid-free and base-free technique for synthesizing hierarchically porous carbon nanosheets. The as-made NHCNs possess high specific surface area (1597 m²·g^-1), abundant micro-/mesopores together with a moderate content of O, N heteroatom. These unique structures give NHCNs electrodes excellent supercapacitor performance. In the KOH electrolyte, NHCNs electrodes show high specific capacitance and good cycle stability.

This study investigates the flame geometrical features of the gas-solid jet diffusion flame (GSJDF). A new facility is designed and built using the Venturi effect, by which the jet diffusion flame can entrain the micron-sized solid particles at constantrate. The uniform white quartz sands of 147 μm and 178 μm in diameters were used for test, respectively. In particular, the gas jet diffusion flame (gas jet fire) formed by closing the side sand inlet is compared with it. Theoretical analysis and experimental result make sense that the addition of sand reduces the flame temperature, and then increases the flame height and the lift-off height by increasing the flame Froude number and decreasing the flame burning speed, respectively. The GSJDF of 147 μm sand has a higher flame height and lift-off height than that of 178 μm sand, for the total mass of 147 μm sand entrained into the flame is larger and so leads to a less flame temperature. In addition, the GSJDF holds a larger trend to produce the lift-off phenomena and a higher flame height than the jet diffusion flame, which also indicates the role of sand in the flame temperature reduction.

Explosion venting and explosion suppression are two important means to reduce the hazard of dust explosion in industry. Therefore, the coupling of the two methods to reduce the hazard of dust explosion is worth to attention. The influence of CO₂/N₂ on the pressure release process of lycopodium powder was experimentally studied with different discharge diameters and static activation overpressure by employing standard 20 L spherical dust explosion device with a lateral venting device. The thermogravimetric analysis method was used to analyze the thermogravimetric changes of lycopodium dust in the atmosphere of CO₂ and N₂ respectively. The results show that at 20 mm discharge caliber, with the increase of CO₂/N₂ concentration, the reduction amplitude of discharge pressure gradually increases, and the reduction effect of CO₂ on the maximum overpressure of dust explosion discharge is better than that of N₂. The reduced pressure basic linearly with the increase of CO₂ concentration decreased. The reduced pressure began to be consistent when adding 10% concentration of CO₂ or N₂. For the 40 mm venting diameter, the value of reduced pressure when added CO₂ is slightly lower than that of N₂, from 6% to 8%. For the 60 mm venting diameter, with the increase of CO₂/N₂ concentration, the reduction of the reduced pressures are basically the same, and when the added concentration is no more than 8%, it has little influence on the amplitude reduction of the system reduced pressure. According to the TGA curve, in the heat flow conditions of N₂ atmosphere and CO₂ atmosphere, the pyrolysis process of lycopodium began to show significant differences around 370℃. The pyrolysis rate of lycopodium in CO₂ atmosphere was faster than that in the N₂ atmosphere, so the presence of CO₂ in this process promoted the pyrolysis of lycopodium. With the further increase of pyrolysis temperature, the inhibition effect of CO₂ on the pyrolysis of lycopodium powder began to show gradually.

Leakage of high-pressure gas storage tanks is very easy to induce jet fire. By building a jet fire experiment device with different jet angles under the restriction of the tank wall, the jet fire with restricted flow field near the nozzle was systematically studied, and the test repeatability of the device was verified. Experimental results show that the lift-off height of confined jet fire is less than that of the free jet. Numerical simulation confirms the effect of tank wall on the air entrainment that dominates the lift-off. The flame length of vertical free jet is less than that of vertical confined jet, but the flame length decreases with the increase of the inclined angle for both free and confined jet fires. The critical Froude number to distinguish the buoyancy and momentum-dominated jet fire, is constant despite the jet angle and the restriction condition of space. The study also found that the blocking effect of tank wall will reduce the liftoff velocity and increase the blowout velocity of the jet flame, as compared to the free jet.