Deep eutectic solvents (DESs) are new type of ionic liquid alternatives, usually composed of a certain stoichiometric ratio of hydrogen bond acceptors and hydrogen bond donors via hydrogen bonding association. Because of its low cost, non-toxicity, good thermal stability, low saturated vapor pressure and electrical conductivity, it has been widely used in many fields such as organic synthesis, material chemistry, electrochemistry, biomass degradation, catalysis and so on. In recent years, with the increasing demand for efficient energy storage and heat transfer in modern society, the application of low eutectic solvents in the fields of energy storage and heat transfer has attracted extensive attention from researchers. In this paper, the research progress on energy storage and heat transfer of low eutectic solvents in recent years is reviewed in detail from the perspective of “storage and transfer”. It is mainly divided into the following two parts from the perspective of different energy transfer forms: as a phase change energy storage material to meet the requirements for latent heat, phase change temperature and thermal stability, and as a highly efficient heat transfer working fluid to meets the demand for effective heat transfer.

Bio-oil is a renewable carbon-neutral resource that has shown great potential in the production of liquid fuels and value-added chemicals. Large-scale use of bio-oil could help achieve carbon neutrality. Bio-oil requires upgrading to improve its application value because of its inherent corrosion and chemical instability. Electrocatalytic hydrogenation (ECH) can realize the bio-oil hydrogenation under atmosphere temperature and pressure. ECH can be easily controlled by regulating the potential, and have a high energy efficiency. It is a carbon neutral process which provides a new option for bio-oil upgrading. The research progress of ECH of bio-oil in recent years was reviewed, and the mechanisms of different bio-oil model compounds in the ECH process were analyzed. The examples of ECH of real bio-oil samples were also discussed to prove the feasibility of electrocatalytic application in bio-oil upgrading. Finally, in view of the difficulties and challenges faced by ECH of bio-oil, the research direction and focus in this field in the future were proposed. The prospects of industrial application of the electrocatalytic hydrogenation upgrading of bio-oil are prospected.

The organic-inorganic composite solid electrolyte not only has the advantages of polymer electrolyte with high flexibility and interface compatibility, but also possesses the merits of improved ionic conductivity and mechanical properties. However, it is difficult to construct a highly dispersive system for the preparation of such composite electrolytes, and it is also a great challenge to regulate the interfacial percolation structure of inorganic fillers with strong molecular interaction. Chemical modification or in-situ synthesis of inorganic fillers by functional organosilane is an effective strategy to solve the problems mentioned above. In this review, the research progress of using functional organosilane for organic-inorganic composite solid electrolytes through surface modification, in-situ synthesis of inorganic fillers, as cross-linking center, or preparation of ionogel based composite solid electrolytes are summarized in detail. The relationship between the organosilane functionalized fillers and the structure/properties of solid electrolytes are disclosed. Finally, the future application of functional organosilane in organic-inorganic composite solid electrolytes is summarized and prospected.

Using renewable clean energy-solar energy to convert CO₂ into carbon monoxide, methane, methanol, etc., has attracted more and more attention because of its potential to provide sustainable fuels and solve global warming problems. Iron-based materials have broad application potential in the field of photocatalytic reduction of CO₂ due to their metal/semiconductor properties and unique electronic structure. According to this, various iron-based catalysts with high catalytic activity have been designed to enhance the efficiency of photocatalytic reduction of CO₂. This article reviews recent advances in the field of photocatalytic reduction of carbon dioxide based on iron-based catalysts. The structural characteristics and catalytic activity of iron-based catalysts are described and compared. Finally, the problems to be solved and the future development direction of iron-based catalysts in the field of photocatalytic reduction of CO₂ are summarized and prospected.

The stable phase equilibria of ternary system CaCl₂-SrCl₂-H₂O, CaCl₂-BaCl₂-H₂O and SrCl₂-BaCl₂-H₂O at 338.15 K were studied by isothermal dissolution equilibrium method, and then the quaternary system CaCl₂-SrCl₂-BaCl₂-H₂O was studied. According to the experimental data, the phase diagram and density composition diagram of ternary system, the space diagram, phase diagram, water diagram and density composition diagram of quaternary system were drawn respectively. The results show that there is no double salt or solid solution in the quaternary system CaCl₂-SrCl₂-BaCl₂-H₂O. The stable phase diagram of the quaternary system consists of one invariant saturation point, three univariate solubility curves and three salt crystallization regions at 338.15 K, corresponding to the crystallization regions of BaCl₂·2H₂O, SrCl₂·mH₂O(m=2,6) and CaCl₂·2H₂O respectively. The solubility of the ternary system CaCl₂-SrCl₂-H₂O, CaCl₂-BaCl₂-H₂O and SrCl₂-BaCl₂-H₂O at 338.15 K were calculated by DFT model. The calculated results are basically consistent with the experimental data. The study of stable phase equilibria of quaternary and ternary systems of CaCl₂-SrCl₂-BaCl₂-H₂O can provide data basis for comprehensive development and utilization of calcium-strontium-barium resources in oilfield brine.

A high-temperature hot-stage microscope was used to study the crystal growth rule and morphological characteristics of the crystallization process of non-Newtonian coal ash slag, and obtain parameters such as the type transformation and the aspect ratio change of the cinder crystals with different chemical compositions. Based on the crystal growth rule from the experiment, the viscosity model of the suspension was modified coupled with the crystal morphology, aspect ratio and the relationship between the slag solid phase and temperature. A viscosity-temperature prediction model suitable for non-Newtonian slag was established in this study, which was compared and verified with the measured viscosity-temperature curve. The model considered the single-phase and multiphase crystal morphology features of feldspar, melilite, anorthite, and merwinite, etc., mainly precipitated as monoclinic or triclinic crystal systems. The model was also modified by combining the parameters of solid fraction of coal slag (range 0≤? ≤0.8) and aspect ratio (1.0—16.0). The results showed that the model was limited as listed conditions, including acidity/basicity ratio of coal slags with ranged of 0.5—3.0, the total content of silicon and aluminum oxides from 35% to 70%(mass), the CaO content lower than 30%(mass), MgO content from 0 to 10%(mass), and the Fe₂O₃ content lower than 16%(mass).

Solar cracking of methane has the advantages of high product purity and environmental protection. In this paper, flow field in a solar tube reactor for high-temperature cracking of methane is optimized through computational fluid dynamics (CFD) simulation by adjusting structure of the tube reactor under turbulent conditions. The carbon particle generation and aggregation model were introduced to calculate the heating effect of solar radiation more accurately. And the discrete-ordinates method (DO) model was used to solve radiation model. A jet flow and baffles were introduced to adjust and optimize the flow field. The baffle height, jet velocity and angle were optimized to enhance the reaction process. The Pareto optimal solution is screened through the definition method, and the Pareto optimal solution is encrypted with the machine learning prediction algorithm to obtain the actual operation encryption curve and corresponding operation parameters. As a result of the optimization, the conversion rate of methane is increased by about 8%. On the basis of the conversion rate, the viscosity dissipation, which represents the increase in strengthening costs, is used as an indicator to filter out the discrete Pareto optimal solution. The support vector regression (SVR) algorithm is used to interpolate the discrete Pareto optimal solution to obtain the operating curve, the corresponding jet angle and jet velocity.

The complex flow structure and interface reaction in the T-jet reactor under different Reynolds numbers (20<Re<420) were visualized by using planar laser induced fluorescence (PLIF) technology and phenolphthalein color reaction. With the increase of Re at inlet, separation flow, steady engulfment flow, unsteady engulfment flow and unsteady symmetric flow displayed successively in the reactor. In particularly, characteristics of the interfacial reaction in T-jet reactor at different flow modes were investigated. The mixing effect, product concentration distribution and time evolution were analyzed combined with the flow field structure. The influence of complex flow field on mixing and interfacial reaction was revealed. The results showed that the three-dimensional vortex structure of engulfment flow makes the fluid entrains with each other, and the layered fluid interface is formed by folding and stretching, which greatly increases the interface contact area of reactants, and improves the mixing and reaction degree significantly. And the product concentration is high and distributed uniformly.

Metal foam has large specific surface area and high thermal conductivity, and can be used to enhance heat transfer in refrigeration and air-conditioning systems by filling it in the heat exchange tube. The flow boiling heat transfer and pressure drop characteristics of R1234ze(E) in metal foam filled tubes are experimentally studied. The experimental conditions cover vapor quality of 0.1—0.9, mass flux of 90—180 kg·m^-2?s^-1 and heat flux of 12.4—18.6 kW·m^-2. The test samples are copper foam filled tubes with the pore density ranging from 10 PPI to 40 PPI and the porosity ranging from 90% to 95%. The experimental results show that, the heat transfer coefficient and two-phase pressure of R1234ze(E) are 2%—10% and 30%—42% lower than those of R410A, respectively. As the vapor quality increases (x>0.8), the increment in heat transfer coefficient of the metal foam filled tube is more significant under low heat flux conditions. Metal foam enhances flow boiling heat transfer at the cost of increased pressure drop, metal foam effect factor for heat transfer ranges from 1.23 to 2.90 and effect factor for pressure drop ranges from 6 to 45. New correlations for flow boiling of R1234ze(E) in metal foam filled tubes is developed. The predicted values of heat transfer coefficient and two-phase pressure drop agree with 95% of experimental data within a deviation of ±15% and ±25%, respectively.

Understanding the generation characteristics of microbubbles in centrifugal pumps is essential for optimizing the performance of existing microbubble generation devices based on rotating equipment and improving the pollutant removal rate of industrial wastewater and waste gas. Recognizing bubble break-up and coalescence, this paper examines how microbubbles evolve under different inlet gas volume fraction (IGVF) and different inlet bubble size in two-phase rotating flow field by coupling two fluid model (TFM) and population balance model (PBM), which was verified to be effective through comparing with experimental head and average bubble size. The results show that gas accumulation in impeller to be the main factor affecting the performance of bubbles with IGVF increasing, which causes bubble size increase as break-up dominated turn to coalescence dominated in impeller. Furthermore, the influence of inlet bubble size on outlet bubble size is sensitive to IGVF. Outlet bubble size increases first and then decreases with inlet bubble size increasing at low IGVF, while this influence is not obvious at high IGVF by gas accumulation in impeller.

Micro particle image velocimetry (Micro-PIV) system was used to study the flow field characteristics of deionized water in micro pin fin arrays with diameter of micro pin fin D=0.4 mm in Reynolds number (Re) range of 50—800. The streamline distribution and velocity field in the staggered and in-line micro pin fin arrays were obtained at different Reynolds numbers. The effects of Re and micro pin fin arrangement on vortex structure and velocity distribution in the wake region were analyzed. The results showed that in the range of Re=50—700, the vortex structure appeared in the staggered and in-line micro pin fin arrays. When Re=800, the vortex shedding began in the staggered micro pin fin array. The vortex length in the wake region of the staggered micro pin fin array increased with the increase of Re. While for the in-line micro pin fin array, the vortex length increased with the increase of Re at low Re, and kept the value of the longitudinal micro pin fin spacing when Re≥300. The streamwise velocity in the main flow area of the in-line micro pin fin array was higher than that of the staggered micro pin fin array. While the transverse velocity in the staggered micro pin fin array was higher than that of the in-line micro pin fin array, and the maximum value was about 25% higher than that of the in-line micro pin fin array. The staggered arrangement of the micro pin fin enhanced the mixing of the fluid in the micro channel.

In a two-dimensional bed with Geldart D glass beads particles, the gas-solid flow process in the rolling fluidized-bed was investigated as well as the time-averaged total pressure drop, which produced when the gas passing through the fluidized bed, under the range of different superficial gas velocities U_g=0.267—0.978 m/s, the rolling amplitudes Θ=5°—15°, and the rolling periods T=8—20 s. The influence of bed rolling on the gas-solid flow characteristics was analyzed by comparing to that in the conventional vertical and inclined beds. It turned out that, when the average angular velocity ω_ave>2(°)/s, the value of the time-averaged total pressure drop in the rolling fluidized bed was lower than that in the vertical bed. Moreover, it was higher than that in the inclined bed, which had the same maximum inclination angle as it in the rolling fluidized bed. The pressure drop caused by inertial force was less than 0.15 kPa, which had little effect on the pressure drop of the bed. The inertial force had little effect on the pressure drop of the bed. The phenomenon of gas accumulation appeared near the wall, which was caused by the inclination of the bed. The gas-solid flow characteristics in the rolling fluidized bed were mainly affected by the gas accumulation. Thus, there existed the defluidization regions, e.g., the fixed beds and moving beds. The particle amounts in the fluidization regions were then reduced as well as the static pressure in the vertical direction of the bed. The existence of the non-fluidized area will also cause the gas velocity in the fluidized area to be higher than the superficial gas velocity of the vertical bed. The ratio of the apparent velocity of the two in this paper is 1.04—1.49.

At present, the transport of nanoparticles in porous media such as soil is mostly described by a single-collector removal efficiency (η). However, this efficiency only considers the collecting effect of a single solid matrix, and does not consider the trapping effect of the pore space between the porous media such as T - E model. To address this issue, the water retention capacity (f_r) was employed to reflect the number of small pores and the existing T-E model was modified. Research has shown that the transport of nanoparticles through columns with the same porosity (f) is not the same, but inversely proportional to the water retention capacity, which has been neglected in previous research. On this basis, the collector contact efficiency by the interception mechanism (η_I) is adjusted to be dependent on both porosity (f) and water retention capacity (f_r); thus, the original model was optimized. Furthermore, breakthrough experiments on nanoscale silica particles (nSiO₂) through the sand column and breakthrough experiments on nano titanium dioxide (nTiO₂) through the sand column with different particle sizes proved that the optimized model is applicable to porous media with different particle sizes and is more accurate in predicting the transport of nanoparticles in porous media.

The transient flow behavior and acoustic characteristics of the liquid level fluctuation caused by the near-simultaneous rupture of double hovering bubbles at the free liquid surface were observed by simultaneous flow field-acoustic tests. The time-frequency spectrum of acoustic signal is extracted by short-time Fourier transform (STFT), and the bubble burst process image and sound pressure spectrum diagram are analyzed simultaneously. The results show that the double hovering bubbles burst one after another, the moment of bubble Ⅰ jet formation overlaps with the rapid contraction of bubble Ⅱvolume, and the phenomenon of sound pressure surge is 0.5 Pa higher than that of single bubble burst. The peak values of sound pressure are all larger than the amplitude of sound pressure caused by the rapid volume shrinkage and the jet formation of the single bubble liquid surface rupture. The peak value of sound pressure also exists when the liquid level fluctuation caused by the double hovering bubble burst propagates in the opposite direction and overlaps. The acoustic signal center frequency at the moment of bubble Ⅰ jet formation and sharp shrinkage of bubbleⅡvolume overlap is 1078 Hz. The superposition time of the liquid surface vibration wave caused by the double-hovering bubble burst has two frequency domain peaks, the center frequencies are 1242 Hz and 2063 Hz, respectively.

In order to study the influence of abnormal shape on the performance of heat pipes, three copper-water heat pipes were experimentally studied. The heating temperature range is 50—90℃, and the cooling water flow range is 40—104 L/h. Comparing the starting performance and isothermal performance under different working conditions, the results show that abnormal-shaped pipes may appear “temperature hysteresis” phenomenon when the heating temperature is low, which significantly increases the start-up time, but the start-up time of all working conditions is within 4 min; the abnormal shape makes the isothermal performance of the heat pipe worse but it is still within the acceptable range. The maximum heat transfer power, the heat transfer resistance of the evaporation section, and the overall thermal resistance under different application conditions have been studied. The experiment shows that when the heating temperature is low， the special shape has a greater influence on the maximum heat transfer power and heat transfer resistance. When the heating temperature is greater than 80℃， the maximum heat transfer power difference between the special shape tube and the straight tube is reduced to 30%， and the heat transfer resistance at this time reaches the level of 10^-2.

Exploring the kinetic principle of static droplet evaporation plays an important role in many related industrial applications. Despite that this phenomenon has been extensively studied over recent decades, an unsolved problem is that how exactly the temperature changes in the adjacent of contact lines. We report in this work a direct experimental measurement revealing the temperature profile of the free interface near contact lines of a sessile drop during the evaporation stage with pinned contact lines. We adapted a microscopic fluorescence-based thermometry, and found that the temperature at the free interface changes drastically near contact lines, forming a concentric fringe pattern which evolves over the whole evaporation process. We attribute the formation of such fringe pattern to a combined mechanism comprising of locally enhanced evaporative cooling near drop edges and a set of thermobuoyancy-driven convective rolls. The new fundamental understanding provided in this work reveals insights into the evaporation dynamics, promising advances in various applications of heat transfer systems.

One-step catalytic epoxidation of propylene with H₂ and O₂ to produce propylene oxide (PO) has incomparable advantages over traditional industrial processes for PO production because of economic and environmental considerations. The formation of byproducts from PO isomerization catalyzed by TS-1 was studied considering that the bifunctional Au/TS-1 catalysts have exhibited superior PO performance in this reaction. By combining with the catalytic performance of PO isomerization and FT-IR results over the uncalcined TS-1 (TS-1-B) and Au/TS-1-B catalyst with blocked micropores, the formation pathways and corresponding energy changes of propanal and acetone over Ti-Defect site were explored with theoretical calculations. The results show that the isomerization of PO on TS-1 mainly undergoes two transition states of carbon-oxygen bond cleavage and hydrogen atom rearrangement, and the bidentatepropoxy species intermediate with a five-member ring. Compared to propanal, acetone has a lower selectivity from PO isomerization because of the higher transition state energy barrier of hydrogen atom rearrangement during its formation process. The PO adsorption and isomerization mechanism on TS-1 disclosed here will provide a theoretical basis for the structural modification of the titanium-based propylene epoxidation catalyst to enhance PO desorption, thereby improving PO selectivity.

La_0.8Sr_0.2Mn_1-xCu_xO₃ (x=0,0.1,0.2,0.3,0.4) perovskite catalysts with Sr²⁺ and Cu²⁺ substituted at A and B sites were prepared by flame spray synthesis method for CO catalytic oxidation, and the effects of water vapor and CO₂ on the CO oxidation activity of the catalysts were investigated. The structure and catalytic activity of La_0.8Sr_0.2Mn_1-xCu_xO₃ catalysts were characterized and analyzed by XRD, SEM, EDS, BET, XPS, H₂-TPR and O₂-TPD. The catalysts prepared by flame spray synthesis exhibit good perovskite phases, loose porous structure and catalytic oxidation activity. La_0.8Sr_0.2Mn_0.9Cu_0.1O₃ achieves 50% CO and 90% CO conversion at 119.4℃ and 133.3℃, respectively. The doping of water vapor and CO₂ will form competitive adsorption with CO on the surface of the perovskite, resulting in the performance degradation of the five catalysts. And La_0.8Sr_0.2Mn_0.9Cu_0.1O₃ can achieve 90% CO conversion at 150.2℃. In the continuous stable catalytic oxidation test, the catalytic activity decreased less than 10%. Combined with the above CO catalytic oxidation experiment, the catalyst prepared by the flame spray synthesis method has good stability and catalytic activity, and is suitable for preparing a perovskite catalyst with high CO catalytic oxidation activity.

The thermal cracking and catalytic cracking reaction performance of C₅ alkanes were investigated, and the cracking reaction products of n-pentane and isopentane were found to be different. Furthermore, the pyrolysis mechanism of n-pentane and isopentane was analyzed, and the difference between the cracking of n-pentane and isopentane to produce light olefins and methane was revealed. The results showed that under thermal pyrolysis conditions, the selectivity of (ethylene + propylene) of n-pentane was higher than that of isopentane, the selectivities of isopentane thermal pyrolysis products butene and methane were higher than that of n-pentane. At 650℃, the selectivities of n-pentane and isopentane thermal pyrolysis products including (ethylene + propylene), butene, and methane were 37.48%, 7.23%, 6.75% and 19.57%, 25.16%, 9.36%, respectively. However, under catalytic pyrolysis conditions, the selectivities of isopentane catalytic pyrolysis products (ethylene + propylene), butene, and methane were higher than that of n-pentane. At 650℃, the selectivities of n-pentane and isopentane thermal pyrolysis products including (ethylene + propylene), butene, and methane were 37.16%, 9.11%, 7.80% and 47.70%, 14.45%, 13.79%, respectively. In addition, it was found that isoalkanes are easier to crack to butene and methane than n-alkanes under high temperature cracking conditions.

Catalytic cracking of light olefins ({\mathrm{C}}_{\mathrm{4}}^{=}/{\mathrm{C}}_{\mathrm{5}}^{=}) can produce high value-added product {\mathrm{C}}_{\mathrm{3}}^{=}, meanwhile achieve efficient utilization of C₄/C₅ resources, which has very important research significance and industrial application value. The main technical problem of catalytic cracking of {\mathrm{C}}_{\mathrm{4}}^{=} is how to obtain high selectivity of olefin products, especially the target product {\mathrm{C}}_{\mathrm{3}}^{=} and to reduce non-olefin by-products, and its core lies in the development of high-efficiency catalysts. At present, the main industrial catalyst is modified ZSM-5. Titanium silicate molecular sieve TS-1 is a high-efficiency catalyst in the liquid phase ammoximation process of industrial cyclohexanone , which shows a typical Br?nsted acid property after deactivation. Based on this, the deactivated TS-1 as an efficient catalyst for catalytic cracking of {\mathrm{C}}_{\mathrm{4}}^{=} to produce {\mathrm{C}}_{\mathrm{3}}^{=} was developed, and the result indicated that the deactivated TS-1 after acid treatment and potassium ion (K⁺) exchange could show the feature of high activity, high selectivity and high stability. Combined with nitric acid treating modification, K⁺ exchange experiment and the characterization techniques such as UV-Vis (UV-visible spectroscopy), FT-IR (Fourier transform infrared spectrometer) and NH₃-TPD (temperature-programmed desorption of ammonia), it was found that the catalytic cracking active center of deactivated TS-1 is Br?nsted acidic silyl hydroxyl group (Si—OH(Ti)) adjacent to the titanium hydroxyl group. The structure of this Br?nsted acid site is completely different from the skeleton bridge Br?nsted acid site (Si—(OH)—Al) of ZSM-5, meanwhile shows relatively weak acid strength. The unique acid property of Si—OH(Ti) could promote the main reaction path of catalytic cracking of {\mathrm{C}}_{\mathrm{4}}^{=} to produce {\mathrm{C}}_{\mathrm{3}}^{=} and inhibit the side reaction path of hydrogen transfer reaction. The discovery and application of the special Br?nsted acid center of the deactivated TS-1 waste catalyst can provide a new idea for resource utilization of solid waste resources of spent catalyst.

Pt/USY catalysts were prepared by using Pt as the active component and USY zeolite treated with different concentrations of oxalic acid as supports. For the investigation of concurrent hydrogenation saturation and isomerization, phenanthrene was chosen as a model compound. Since the hydrogenation reaction is prone to occur on the metal active site Pt and the isomerization reaction and cleavage reaction are prone to occur on the acid site of the USY carrier,the influence of the strength and concentration of acid sites on the phenanthrene conversion and product distribution was investigated. The particle size and dispersion of Pt sites affect the conversion rate of phenanthrene, which is faster over Pt/0.05-USY and Pt/0.1-USY than over Pt/USY catalysts. Perhydroanthracene is the key intermediate in the hydrogenation of phenanthrene to alkyl adamantane. The Br?nsted acid sites of the support promote the isomerization of alkyl adamantane. The formation of the isomer alkyl adamantane needs to be completed at the Br?nsted acid site. While decreasing the content and the strength of acid site in USY, the cracking reaction is inhibited which enhances the phenanthrene hydrogenation reaction to yield more hydrogenation saturated products. The yield of alkyl amantadane was 2.3% using Pt/0.1-USY catalysts.

Both phenols and syngas are important basic chemical raw materials in industrial production. In this paper, self-made activated carbon was used as a catalyst, and cellulose was used as a raw material to achieve the simultaneous enrichment of phenol in the liquid phase product of catalytic pyrolysis and CO in the gas phase product. It was found that all of the potassium in ash, the mass ratio of catalyst/cellulose and the catalytic temperature affected the quality of gas and liquid products. Results showed that the presence of potassium was against the improvement of pyrolysis products quality. Although, the relative content of phenols in bio-oil was increased, but its actual yield was decreased. Meantime, both the concentration and yield of CO in pyrolytic gas decreased. The optimum products were obtained at the pyrolysis temperature of 450℃ with the catalyst/cellulose mass ratio of 1∶1. At this time, the phenolic substances in the bio-oil accounted for 62.31% of the relative content of the detectable organic matter, of which phenol was 45.37%, and the yield was 1.78%(mass). Besides, the concentration and yield of CO in pyrolytic gas were 69.21%(vol) and 169.95 ml/g, with the calorific value of 12.93 MJ/m³.

For the non-specific adsorption of affinity chromatography resin, a quantitative characterization method was established based on the pulse response method. With bovine serum albumin, yeast broth and CHO cell culture solution as the typical impurities, four Protein A affinity resins and two matrix microspheres were used to investigate the non-specific adsorption behaviors under different pH and salt concentration. It was found that all four resins and two matrix microspheres showed some amount of impurity adsorption. The non-specific adsorption was relatively strong under acidic conditions. Different mechanisms of non-specific adsorption could be identified, i.e. electrostatic interaction, hydrophobic interaction and both. According to the comparison of resins and matrices, the non-specific adsorption of agarose-based resin mainly relied on the interactions between matrix microsphere and the impurities, while the polymer-based reins tested showed stronger adsorption of impurities than its matrix. The results demonstrated that the method developed in the present work is feasible and could be used to quantify non-specific adsorption, explore the mechanisms and provide new approach for resin development.

Vapor permeation (VP) membrane separation does not have the risk of membrane fouling and has broad application prospects in the production of bioethanol. The polydimethylsiloxane (PDMS) membrane and the novel PDMS mixed matrix membrane (ZIF-L/PDMS) prepared by embedding two-dimensional zeolitic imidazolate framework-L (ZIF-L) into PDMS matrix were used as separate modules to separate ethanol from fermentation of inulin hydrolysate in a VP coupled with fermentation system(VP-fermentation). The separation performance and fermentation performance during coupling process were analyzed. The effects of separation methods, membrane types and operation conditions on the separation performance were explored. The results showed that ZIF-L/PDMS mixed matrix membrane for the separation of 5%(mass) ethanol aqueous solution by VP showed better performance than pervaporation (PV) when vapor cyclic flow was 1.5 L·min^-1, and the normalized total flux and the separation factor reached 1148.78 g·m^-2·h^-1 and 19.14, respectively, suggesting the ethanol separation performance was significantly improved. Furthermore, the ZIF-L/PDMS membrane exhibited an impressive permeability and ethanol selectivity in VP-fermentation process. Compared with the literature reports, it achieved the best ethanol removal effect, which greatly enhanced the ethanol production efficiency. The ethanol yield and productivity reached 0.421 g·g^-1 and 3.07 g·L^-1·h^-1, respectively, which were higher than that in independent batch fermentation. Therefore, ZIF-L/PDMS mixed matrix membrane exhibits great application potential in the in-situ removal of ethanol from fermentation.

In order to obtain high-performance mixed matrix membrane to effectively capture CO₂ in flue gas, this paper designed a N,S co-doped porous carbon sphere with excellent diffusion and adsorption selectivity for CO₂ as an additive to achieve the efficient separation of CO₂/N₂ from flue gas. Glucose with rich oxygen groups as the carbon source and thiourea as nitrogen and sulfur source are selected to prepare the nitrogen and sulfur co-doped carbons (NSC) by hydrothermal method. The porous structure of NSPC is produced by the activation of NSC with KOH. FTIR, XRD and BET tests indicate the successful synthesis of NSPC, which has high specific surface area and microporosity. The optimal ratio of glucose to thiourea, the optimal ratio of NSC to KOH in the synthesis of NSPC, the effect of NSPC content, feed pressure, test temperature on the performance of the membrane are studied. It proves that the nitrogen, sulfur-containing CO₂ affinity sites and micropores in NSPC have beneficial effects on the gas separation performance of the membrane. The results show that when the NSPC content is 3%(mass), the performance of membrane is the best at 25℃ and 0.2 MPa. The CO₂ permeability is 589 Barrer, and the CO₂/N₂ selectivity is 64. The performance of the membrane in the mixed gas is slightly lower than that in the pure gas, and it can remain stable for 360 h, which has good industrial application prospects.

Freshwater resources are increasingly scarce, and membrane desalination technologies continue to develop to meet the world's freshwater supply needs. However, development of high performance membranes for this technology is still under way. ZSM-5 zeolite membrane has been widely used in dehydration of organics due to the uniformed pore structure, suitable pore size (0.51—0.56 nm) and adjustable Si/Al ratio. Considering its pore size is between the size of water molecules and most of the salts, it exhibits excellent selectivity and good permeability and stability in the application of organic matter dehydration and separation. In this work, ZSM-5 zeolite membrane was synthesized on the macroporous α-Al₂O₃ support using secondary growth method. The effects of crystallization time and Si/Al ratio of synthetic solution on membrane formation and desalination performance of ZSM-5 zeolite membrane were investigated. XRD, SEM, EDS and water contact angle characterizations were used to examine the phase structure and crystallinity, framework structure composition of the membranes. The results showed that, high performance ZSM-5 zeolite membrane with Si/Al ratio of 10 and contact angle of 17.5° was obtained with recipe of n(Al₂O₃)∶n(SiO₂)∶n(Na₂O)∶n(NaF)∶n(H₂O) = 0.05∶ 1∶0.21∶1.01∶55 at 175℃ for 48 h. The synthesized membrane was used for seawater desalination by pervaporation, and a high water flux of 8.35 kg·m^-2·h^-1 with ion rejection of 99.99% was obtained for the desalination of 3.5%(mass) NaCl aqueous solution at 75℃, indicating the ZSM-5 zeolite membrane possesses great potential for seawater desalination.

Based on Gibbs free energy theory, a generalized production system and its free energy balance method that unify the environmental pollution control of the process industry and the product processing process are proposed. The thermodynamic cost of environmental pollution is characterized by the ratio of free energy dissipation (RFED) for pollutant emission-diffusion to free energy consumption necessary for product manufacturing. Through model analysis, it is clarified that enclosed exhausts cycling is a technical route of exhausts treatment with general thermodynamic significance. Taking the current standard of air pollutants emission for wet process phosphoric acid (WPA) industry as an example, the model calculation reveals the RFED value is 2.54, which means the free energy dissipation for exhaust pollutant emission is 1.54 times more than the effective free energy consumption for products. This is the common situation in end-of-pipe treatment processes which abuse air as heat and mass carrier, which is urgent to improve by implementing enclosed exhausts cycling process and developing corresponding key technology of exhaust purification emphasized on lower grade heat and mass separation and recovery, in order to strengthen the economy of enclosed exhausts cycling with the profit increase brought by emission reduction. Therefore, some promising achievements, obtained from a series of unit operation technology R&D of enclosed exhausts cycling for WPA, are preliminarily reported in this paper for arousing more response in this field.

Based on a model analysis of free energy dissipation in chemical processes it is pointed out that the ambient air quality decline, induced by dispersion of NO_{xand N2O emission from traditional ammonia/air oxidation nitric acid (AAtNA) process, accounted as environment loss of free energy will reach 66.2% of that effectively consumed in production. Hence a new process of green power to nitric acid (GPtNA) is proposed for elimination of pollution source by enclosed exhaust cycling. For the purpose of carbon replacement by power, the units of water electrolysis and air separation are coupled into the loops of high pressure catalytic ammonia synthesis and dual-pressure catalytic oxidation/absorption nitric acid to supply green hydrogen, oxygen and nitrogen sources. Compared with AAtNA process, 0.356 t carbon consumption can be avoid therefore 1.31 t CO2 emission abated, plus 1.01—1.70 kg NOx and 1.01—1.70 kg N2O recovered for per ton nitric acid (100% HNO3) produced by GPtNA process, meaningful to carbon reducing and pollution abatement for nitric acid industry. Based on the mature industrial technologies of ammonia, nitric acid and air separation, the new process development is also benefited from the frontier achievement of green power to hydrogen. Under the current available power-hydrogen efficiency of 4.3 kW·h/m³, a theoretic power consumption of 2560 kW·h/t for GPtNA process can be competitive to the cost of theoretic ammonia consumption of 269.8 kg/t for AAtNA process under certain power/ammonia price ratio. When the renewable (water, wind, light) electricity price is lower than 0.22 CNY/(kW·h), the GPtNA process has a comprehensive competitive advantage in resources, environment and economy.}

Heat exchanger as an important heat transfer equipment in the chemical process, generally needs to continue to run for a long time, during which due to the continuous accumulation of fouling resistance, heat transfer efficiency of the heat exchanger will gradually decline with time, until it cannot meet the process requirements. In the actual industrial heat exchange process, the process personnel usually carry out margin design on the heat exchanger. However, the heat exchanger needs to run longer or the allowance design is insufficient, the regulating effect of the commonly used flow control strategy gradually deteriorates at the end of the heat exchanger operation while the bypass control scheme cannot realize the continuous control of the whole cycle in the face of the inevitable fouling growth. Therefore, an integral asymptotic model of fouling accumulation was established based on the asymptotic grouth model, which considered the influence of process parameters on the fouling rate. Secondly, taking a small area heat exchanger used for water circulation as an example, the regulating effect of flow control and bypass control under the condition of considering fouling growth is analyzed. Finally, according to the characteristics of slow time-varying and continuous fouling process, a reconstruction control strategy based on heat carrier flow and bypass opening was designed. The operation results of the example show that for the same heat exchanger with limited area margin, this control scheme can prolong its service life and achieve its goal of continuous control throughout the whole cycle.

Combined cooling, heating and power(CCHP) is an effective way to improve the efficiency of comprehensive energy utilization. Its system design and operation strategy are usually coupled with each other. Therefore, it is very important to implement the integration and optimization of the cogeneration system. In this model, the optimization objective is minimizing the annual total cost of the system, in which the investment cost and operation cost in the whole life cycle are considered. The characteristic equations of equipment are developed, including gas turbine, waste heat boiler, absorption chiller, etc., and the fixed and dynamic electrical/thermal efficiency of the gas turbine are considered, respectively. In addition, based on three different operation strategies, including following electric load (FEL), following thermal load (FTL), and following hybrid load (FHL), the energy balance equations of cold, heat, and electricity load demand are developed, respectively. The proposed method is applied to the optimal design and operation of the CCHP system for a typical commercial building. The results illustrate that the reasonable and feasible optimal design of the CCHP system could be obtained only through the comprehensive application of FHL strategy, dynamic electrical/thermal efficiency, and annual load characteristic data.

To solve the problem that the existing dry gas seal surface groove type line equations are not strong enough in geometrical characterization ability and not unified in the geometrical parameter definition, a generalized logarithmic spiral groove geometrical model based on the combination of radial micro-segments to represent arbitrary shape lines is proposed. The generalized logarithmic spiral groove geometrical parameter definition is given, and the steady-state performance of the generalized spiral groove and the typical spiral groove dry gas seal under different pressure and rotating speed conditions, such as the opening force, film stiffness, and leakage rate, are compared. The research focuses on the influence of the two characteristic features, including the generalized spiral angle distribution and the circumferential deflection of profile line, on the performance of the dry gas seal, and the optimal shape of the generalized spiral groove is obtained based on different objective functions. The results show that the profile shape of the upstream side wall of the groove has a significant impact on various steady-state performance parameters, while the profile shape of the downstream side wall only has a significant impact on the leakage rate and film stiffness. The typical logarithmic spiral groove is exactly a kind of surface groove with strong hydrodynamic and hydrostatic effect. It is difficult to significantly increase the load-carrying capacity of the gas film by relying solely on profile optimization of the surface groove. However, optimization of the generalized helix angle distribution under low-pressure and high-speed condition, and proper design of the profile circumferential deflection under high-pressure and low-speed condition are expected to improve the film stiffness and stiffness-leakage ratio of dry gas seals.

In order to improve the lubrication performance of PAO10 system, an oil-soluble ionic liquid was synthesized and compared with T321 and silica. The thermal stability of PAO10 lubrication system was tested by a synchronous thermal analyzer. The tribological properties of different ionic liquids were compared and evaluated by the SRV-IV fretting friction and wear tester. The wear scar morphology was measured by a non-contact three-dimensional profiler and a scanning electron microscope and the wear volume were characterized. The chemical composition and chemical changes of the wear surface were analyzed by EDS and XPS element analysis. The results show that the oil soluble ionic liquids can significantly improve the thermal stability of PAO10 system. It has excellent anti-friction and anti-wear properties no matter at room temperature or high temperature, and greatly improves the bearing capacity of PAO10 system. XPS analysis results show that the tribochemical reaction of polar elements P and S occurs in the friction process, and the tribochemical film formed can effectively inhibit the direct contact between the friction pairs, and improve the friction reducing and anti-wear performance of PAO10 system.

The urease produced by Sporosarcina pasteurii can hydrolyze urea, and the generated CO₂ reacts with calcium chloride to obtain calcium carbonate with different polymorphs by urease in different solutions. The mesoporous hollow micron pure spheroids formed by self-assembly of nanospheres were obtained by urease in the supernatant of fermentation broth. Calcite with 100% was obtained by bacterial urease. Infrared spectrum analysis showed that the elliptical calcium carbonate obtained by crude urease was affected by the hydroxyl groups. The effects of urease activity and reactant concentration on vaterite were explored. It was also found that the obtained pure vaterite is very stable within 7 days and is expected to be used as a drug carrier.

Co-combustion of ammonia with methane or hydrogen can overcome the disadvantages of high ignition energy and slow combustion speed of NH₃ flame. To understand the combustion characteristics of NH₃ as a fuel, a one-dimensional laminar premixed flame numerical simulation was carried out on NH₃-containing fuel, and its laminar flame speed and NO emission characteristics were studied. Five reduced reaction mechanisms proposed in the literature were employed for numerical calculation. The results show that the mechanism of Okafor predicts NH₃/CH₄/air flame with higher accuracy, and the mechanism developed by Xiao simulates NH₃/H₂/air, NH₃/air flame with a moderate accuracy and shorter computational time. Additionally, the effect of equivalence ratio, composition of the fuel mixture and pressure on the concentration of NO in flue gas were studied. The analysis of NO production rate demonstrates that NO is mainly produced by the consumption of OH, H, O radicals and O₂ molecule and the NO consumption mainly takes place through the reaction with NH_i (i=0, 1, 2) radicals for the combustion of NH₃-containing fuel. NH₃-containing fuel burning in rich condition can effectively reduce the NO emission, but the combustion efficiency of rich combustion is low. This can be tackled with the “rich burn - lean burn” staged combustion concept while maintaining the low NO emission at the same time. It is also found that combustion of NH₃-containing fuel with more NH₃ under medium and high pressure is more preferable for reducing NO emissions.

In this paper, biochar (BRC) produced from biogas residue (BR) with three particle sizes (d≤0.15 mm, 0.15 mm <d≤0.25 mm, d>0.25 mm) were obtained by pyrolysis at 600℃. The effects of different particle sizes on the migration and transformation of phosphorus and heavy metals between BR and BRC were systematically studied. And toxicity characteristic leaching procedure (TCLP) leaching toxicity test and potential ecological risk assessment were used to evaluate the safety risk of BR and BRC. The results showed that the phosphorus in BR and BRC were mainly acid-soluble phosphorus (HCl-P), followed by residual phosphorus (Res-P), and the contents of other phosphorus forms were low. TP content showed a decreasing trend with increase of particle size in BR and BRC. Pyrolysis can promote the conversion of H₂O-P, NaHCO₃-P and NaOH-P to HCl-P and Res-P. As the particle size increases, the total amount of Cu and Zn in BR increases, while the amount of Cr decreases, the total amount of Cr and As in BRC increases, and the total amount of Zn and Pb decreases. Meanwhile, the F3+F4 fractions (oxidizable and residue fraction) of Cr, Zn, Pb, As in BR and that of Cr, Pb, As in BRC decreased with the increase of particle size, while Cu, Zn and Cd of BRC showed an opposite trend. The assessment results of TCLP leaching toxicity and potential ecological risk of heavy metals indicate that the heavy metals in BR and BRC are at low risk levels.

Sporosarcina pasteurii induced carbonate-uranium co-precipitation for the remediation of low concentration uranium wastewater under the presence of calcium was studied. The results show that the bacteria can secrete urease to hydrolyze urea to induce calcite and promote its co-precipitation with uranium, so that the removal rate of uranium in wastewater reaches 95.38%. The analysis indicated that Sporosarcina pasteurii was able to tolerate uranium concentrations up to 500 mg/L, while low concentration of uranium had a slight promotion effect on bacterial growth. In addition, the decrease of uranium concentration is directly related to the concentration of Ca²⁺ (C_Ca). The increase of C_Ca improved the uranium removal rate. The temperature at about 30℃ and alkaline environment are favorable to the co-precipitation of uranium and calcite. The precipitate was characterized by XRD and SEM-EDS. XRD analysis showed that the precipitate was composed of calcite. SEM-EDS analysis further suggested that the precipitated component contains uranium element. Combined with the digestion results, uranium was fixed into the precipitated product in the way of co-precipitation during the formation of calcite. This study shows that Sporosarcina pasteurii induced carbonate-uranium co-precipitation has a potential application prospect in the remediation of low concentration uranium contaminated wastewater.

The removal efficiency of humus is the key to catalytic ozone oxidation to degrade the organic matter in the RO concentrate of landfill leachate. Activated carbon-supported metal cerium catalyst (Ce-AC) catalytic ozone oxidation can effectively improve the removal efficiency of humus. In this paper, the Ce-AC catalyst was characterized by XRD, SEM and EDS. The effects of different catalysts on COD removal and biodegradability of RO concentrate were compared. The degradation mechanism of humus was clarified by analyzing the degradation product spectrum. The results show that cerium oxide is loaded on AC in the form of CeO₂ fluorite crystal. After loading, the specific surface area and pore volume of AC decrease, and the average pore diameter increases. Ce-AC had the best removal effect on COD and UV₂₅₄, which were 44.7% and 67.3%, respectively. The effluent biodegradability was significantly improved, and the B/C ratio was increased from 0.06 to 0.47. UV-Vis spectra showed that the degradation efficiency of aromatic compounds representing humus in the system was obvious. Three-dimensional fluorescence spectroscopy showed that the humic substances in the system were degraded to a large extent. The results of fluorescence region integration showed that the removal efficiency of humic substances reached 66.7%. Fourier transform infrared spectroscopy showed that humic substances were oxidized and decomposed into relatively small molecules of carbohydrates and organic amines, sulfur and alcohols.

Emerging contaminants such as triclosan (TCS) and nano-copper (CuNPs) will enter the sewage treatment system and inhibit the biological nitrification performance, and long-term exposure to sludge microorganisms might cause the risk of enrichment and spread of antibiotic resistance genes. The nitrification inhibited by contaminants is improved by adding zero-valent iron in this study. Under the single and combined exposure of TCS and CuNPs, the enhanced effect of zero-valent iron on sludge nitrification was explored by measuring the concentration of ammonia nitrogen in the effluent, and the mechanism of enhanced biological nitrification efficiency by zero-valent iron was investigated by measuring pollutant concentration, nitrification enzyme activity, nitrification functional gene abundance and microbial population structure. Additionally, the influence of zero-valent iron on the fate of TCS resistance gene (mexB) and copper resistance gene (copA) was studied. When nitrification was inhibited by TCS and CuNPs, the introduction of zero-valent iron could increase (0.5%—6.7%) the removal efficiency of ammonia nitrogen in one reaction cycle to a certain extent, and the zero-valent iron was beneficial to the improvement and recovery of nitrification efficiency during long-term operation. Mechanism studies have shown that zero-valent iron could reduce the concentration of Cu²⁺ and TCS in the system, thereby reducing the toxicity of pollutants. In addition, zero-valent iron could increase the activity of two nitrification enzymes—AMO enzyme and NXR enzyme, and increased the abundance of amoA enzyme functional genes, besides, the abundance of Nitrospira and Lacibacter bacteria was increased by the addition of zero-valent iron, thus enhancing the nitrification performance of the sludge. It was worth noting that exposure of TCS and CuNPs would cause the enrichment of mexB and copA genes, meanwhile zero-valent iron would increase the abundance of mexB, copA genes as well, and increase the risk of transmission of resistance genes.

The heat storage type solar heating system based on low temperature radiation heat dissipation is studied. The heat collection characteristics and the heat absorption/exothermic characteristics of phase change heat storage material of the system were analyzed. Variation of temperature field inhomogeneity in phase change heat storage unit was revealed. At the same time, the heat transfer rate of the phase change heat storage unit and the comprehensive utilization ability of solar energy of the system were measured. The operation condition of capillary network was optimized and the system economy was discussed. The results show that in the heat collection and storage stage, the temperature field inhomogeneity of the phase change heat storage unit increases linearly from 0.0265 to the peak value of 0.11 in the heat storage and heating range from 38℃ to 47.7℃. In the range of 47.7℃ to 53.9℃ for heat storage, the temperature field unevenness of the phase change heat storage unit decreases from the peak value of 0.11 to the turning point of 0.0603 with a nearly linear regularity. And the turning point is near the melting point (freezing point). After melting point (freezing point), the unevenness of temperature field tends to stable state distribution. In the stage of heat release and heat dissipation, the internal temperature field of phase change heat storage unit maintains the minimum steady-state uniformity (around 0.020) in the range of 57.9℃ to 55℃. After melting (solidification) temperature point, in the exothermic cooling range of 55℃ to 47.3℃, the temperature field uniformity increases from 0.0238 in a nearly linear pattern to the peak value of 0.0952, and the peak value is near the exothermic solidification peak. After the peak value, the unevenness of temperature field decreases with the heat release time. The effective heat storage of the phase change heat storage unit is 5.0911 MJ, and the heat storage density is 181.51 J/g. The average heat storage rate and average heat release rate are basically the same, which are 1.829 MJ/h and 1.803 MJ/h respectively. In the solar heating system, the efficiency of heat collection and heat storage is 0.3648, the heat release and heat dissipation efficiency is 0.5843, and the comprehensive utilization capacity of solar energy is 0.2132. When the inlet temperature of capillary network is higher than 40℃, the heat dissipation power increases linearly with the inlet temperature, and when the inlet temperature is higher than 52℃, the heat dissipation power stabilizes around 410 W. When the inlet temperature of the capillary network is less than 40℃, the heat dissipation power increases linearly with the inlet temperature, and there is a single peak value of 262 W. When the inlet temperature and heat dissipation temperature difference of the capillary network are 36℃ and 8℃ respectively, the maximum heat dissipation capacity of the capillary network is 65.5 W/m². In heat storage type solar heating system, the optimal ratio of effective heat collection area to heating area is 0.4, the optimal ratio of phase change material mass to effective heat collection area is 15 kg/m², the optimal ratio of heat dissipation area and heating area is 0.35, the initial investment per unit heating area is 225.8 CNY/m², the operation and maintenance cost per unit area is 4.28 CNY/m², and the static investment payback period of the system is 8.7 years. The research has important guiding significance to improve the reliability of heat storage type solar heating system.

Taking the square LiFePO₄ (LFP) /graphite power battery as the research object, the failure mechanism is explored when the battery cycles with 1C current at 45℃. By dissecting the battery, the changes in the thickness, morphology, structure and gram capacity of the positive and negative plates before and after the battery cycle are systematically analyzed. With the continuous cycling of the battery at 45℃, the electrolyte in the battery is gradually decomposed, the loss of Fe dissolution is aggravated, and the growth of SEI film is accelerated, which leads to the large consumption of active lithium and the increase of EIS and battery polarization. The results indicate that the capacity loss of anode which is caused by active lithium consumption and structure change is higher than that in the cathode, which are 6.7% and 22.64%, respectively. Therefore, the battery failure is mainly resulted by the attenuation of dynamic performance of the graphite negative electrode.

In this paper, a simple one-step electrodeposition method was used to prepare Cu²⁺-doped MnO₂ materials. A series of examinations such as XRD, SEM and TEM are employed to describe the characteristic of Cu²⁺ doped MnO₂ samples. As a result, the Cu²⁺ doped MnO₂ materials possess a fluffy porous nanostructure and exhibit enhanced electrochemical performance when as a cathode of aqueous zinc ion batteries. In detail, the specific capacity of Cu²⁺ doped MnO₂ samples exhibit 235 mAh/g in 200 mA/g, which is about 47.8% higher than that of pure MnO₂ sample. Furthermore, the impedance of Cu²⁺ doped MnO₂ is also reduced from 997.3 Ω to 564.3 Ω.

In recent years, hydrogen energy has rapidly become the “new favorite” in the energy field, and is ushering in a period of rapid development of strategic opportunities. However, hydrogen safety issues are still the key to restricting its development, especially the jet fire disaster induced by the leakage of high-pressure hydrogen storage and transportation facilities. In order to explore the process of high-pressure hydrogen leakage and evaluate the changes of the subsequent jet fire characteristics, this paper presents a theoretical analysis and case verification of two experiment cases of high-pressure hydrogen leakage (90 MPa hydrogen reservoir and 6 MPa hydrogen pipeline). The results show that the Abel-Nobel gas state equation is suitable for the description of the leakage process of a variety of high-pressure hydrogen storage and transportation facilities commonly used at present through the model accuracy test. Based on the Abel-Nobel EOS, flame size model, radiation fraction model and thermal radiation model, a prediction model for the process of jet fire resulting from high-pressure hydrogen leakage is established and used to simulate the gas mass flow rate at the leakage exit, hydrogen jet flame length and thermal radiation field in two experiment cases. The calculated results are basically the same with experimental data, which indicates the validity of the prediction model and the rationality of the involved assumptions. Besides, in calculation it also needs to take full account of the energy loss and isothermal flow process during the leakage of high-pressure hydrogen storage and transportation facilities, so as to modify the prediction accuracy of the prediction model. The conclusions hold important practical significance for engineering practice, safe use of hydrogen energy and disaster prevention, etc.

The current environmental problems are becoming increasingly prominent, and the natural refrigerant ammonia as an environmentally friendly refrigerant has once again attracted widespread attention in the scientific community. However, NH₃ has the problem of flammability and explosion, and there are certain safety hazards in practical applications. In this paper, we adopt the quantum chemical density generalized theory calculation method to investigate the combustion and flame-retardant mechanism of NH₃ at the calculation level of M06-2X/6-311+G(d, p), and obtain the microscopic reaction path of the reaction process. It is shown that NH₃ can react with H, O and OH radicals in three ways: firstly, it undergoes its own cleavage reaction to produce H radicals; secondly, it collides with oxygen to produce OOH radicals; thirdly, it collides with reactive radicals to produce new reactive radicals, and NH₃ can react with H, O and OH radicals, and the reaction has a low energy barrier. In addition, the microscopic flame retardant paths of two typical flame retardant groups, F and CF₃, to the combustible molecule NH₃ were calculated to verify their flame retardant effects. In this paper, the combustion and flame retardant mechanism of the combustible work material ammonia is investigated from the microscopic molecular perspective, which provides a reference for the combustion and flame retardant mechanism of the new generation of low greenhouse effect work materials.

Through the self-designed and built small experimental platform, the flame structure change, flame front dynamics and pressure evolution of methane flame propagation process were studied when the blockage rate gradient was 0, 0.05, 0.1 and 0.15 respectively. The results show that when the blockage rate gradient is 0 and 0.05, the flame front will gradually become clear after passing through the obstacles, and then the flame front will sag to the combustion zone. When the blockage rate gradient is 0.1 and 0.15, the front end of the flame is always blurred after passing through the obstacles, and then the turbulent combustion intensifies, and deflagration occurs rapidly in the whole pipeline, and there is no flame front depression phenomenon. The blockage rate gradient has a great influence on the instantaneous flame velocity, but not on the average flame velocity. With the increase of blockage rate gradient from 0 to 0.15, the maximum flame velocity increases obviously, but the average flame velocity is almost the same. In addition, the obstacle group with high blockage rate gradient is conducive to pressure accumulation. With the increase of blockage rate gradient, the peak overpressure increases regularly, and the time to reach the peak overpressure increases accordingly.