The kinetic behavior of esterification between methacrylic acid and methanol catalyzed by NKC-9 resin was studied in a fixed bed reactor. The reaction was conducted in the temperature range of 323.15 to 368.15 K with the molar ratio of reactants from 0.8 to 1.4 under certain pressure. The measurement data were regression with the pseudo-homogeneous (P-H), Eley-Rideal (E-R), and Langmuir-Hinshelwood (L-H) heterogeneous kinetic models. Independent adsorption experiments were implemented to gain the adsorption equilibrium constants of four components. Among the above three models, the L-H model exhibited the best fitting results. The stability of NKC-9 was evaluated by long-term running with the yield of methyl methacrylate no decrease during 3000 h operation. The structure and physicochemical properties of the new and used catalyst were performed by several characterizations including thermogravimetric analysis (TG), scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and so on.

Coal gasification slag (CGS) is a type of solid waste produced during coal gasification, in which heavy metals severely restrict its resource utilization. In this work, the mineral occurrence and distribution of typical heavy metal Cr in CGS is investigated. The leaching behavior of Cr under different conditions is studied in detail. Acid leaching-selective oxidation-coprecipitation method is proposed based on the characteristics of Cr in CGS. The detoxification of Cr in CGS is realized, and the detoxification mechanism is clarified. Results show that Cr is highly enriched in CGS. The speciation of Cr is mainly residual fraction (74.47%-86.12%), which is combined with amorphous aluminosilicate. Cr³⁺ and Cr⁶⁺ account for 90.93%-94.82% and 5.18%-9.07% of total Cr, respectively. High acid concentration and high liquid-solid ratio are beneficial to destroy the lattice structure of amorphous aluminosilicate, thus improving the leaching efficiency of Cr, which can reach 97.93% under the optimal conditions. Acid leaching-selective oxidation-coprecipitation method can realize the detoxification of Cr in CGS. Under the optimal conditions, the removal rates of Fe³⁺ and Cr³⁺ in the leaching solution are 80.99%-84.79% and 70.58%-71.69%, respectively, while the loss rate of Al³⁺ is only 1.10%-3.35%. Detoxification slag exists in the form of Fe-Cr coprecipitation (Fe_1-xCr_xOOH), which can be used for smelting. The detoxification acid leaching solution can be used to prepare inorganic polymer composite coagulant poly-aluminum chloride (PAC). This study can provide theoretical and data guidance for detoxification of heavy metal Cr in CGS and achieve resource utilization of coal gasification solid waste.

Naphthenic base oil is an important lubricating base oil and very scarce in the global petroleum resources. Herein, a series of alkylated tetralin fluids similar to naphthenic base oils were produced by the alkylation of tetralin and α-olefins (n-hexene, n-octene, n-decene) with ionic liquid Et₃NHCl/AlCl₃ as the catalyst, where the applied raw materials are totally derived from the coal chemical industry. The product composition could be controlled by adjusting the feeding ratio of tetralin and olefin. The synthetic fluids were evaluated as lubricating base oils to reveal the structure-property correlations. Their principal physicochemical and tribological properties depend on the chain-length of α-olefins and the number of alkyl groups onto the aromatic rings. Bis-(octyl- or decyl-) alkyl tetralin exhibited good properties in terms of viscosity, thermo-oxidation stability and pour point, as well as friction-reducing and anti-wear performance, showing great potential for producing naphthenic base synthetic oils from coal-based chemicals.

Non-spherical particles exist widely in natural and industrial fluid systems and the motions of non-spherical particles are significantly different from that of spherical particles. In this paper, a simplified model of non-spherical particles considering particle drag correction, lift, and rotation was established. Based on the Eulerian-Lagrangian simulation, the dispersion characteristics of spherical and non-spherical particles with different Stokes numbers in a high-speed turbulent jet were analyzed and compared considering the effect of particle rotation. The results show that, the differences in particle dispersion and radial velocity fluctuation between non-spherical particles and spherical particles in the jet are significant, especially when Stokes number is large. Moreover, the effects of different type of forces on the dispersion of non-spherical particles and spherical particles were compared in detail, which revealed that the change of the Magnus force caused by the increase in the angular velocity of non-spherical particles plays a dominant role in the differences of particle dispersion.

Cytidine 5'-monophosphate (5'-CMP) is an essential nucleotide for additives. In this study, enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes, uridine-cytidine kinase (UCK) and acetate kinase (AcK). The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential (ξ). Among them, ε-polylysine-functionalized sepharose (SA-EPL, ξ = 9.31 mV) showed high immobilization yield (78.8%), which was 4.9-fold than that of nitrilotriacetic acid functionalized sepharose (SA-NTA, ξ = -12.6 mV). The residual activity of affinity co-immobilized enzyme (EPL-Ni/EPL@AcK-UCK) was higher than 70.6% after recycled 10 times. Thus, this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate (ATP) consumption, reduced side reactions, and improved reusability by co-immobilized UCK and AcK on the functionalized Sepharose.

The co-pyrolysis of coal and biomass has proven to be a promising route to produce liquid and gaseous fuels as well as specific value-added chemicals while contributing to mitigating CO₂ emissions. The interactions between the co-processed feedstocks, however, need to be elucidated to support the development of such a thermochemical conversion process. In this context, the present work covers the kinetic analysis of the co-pyrolysis of a bituminous coal with poplar wood. In this research, biomass was blended with coal at two different mass ratios (10% (mass) and 20% (mass)). Thermogravimetric analyses were carried out with pure and blended samples at four heating rates (5, 10, 15 and 30 ℃·min^-1). A direct comparison of experimental and theoretical results (based on a simple additivity rule) failed to yield a clear-cut conclusion regarding the existence of synergistic effects. Kinetic analyses have therefore been achieved using two model-free methods (the Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose models) to estimate the rate constant parameters related to the pyrolysis process. A significant decrease of the activation energy has thus been observed when adding wood to coal (activation energies associated with the blend containing 20% (mass) of biomass being even lower than those estimated for pure wood at low conversion degrees). This trend was attributed to the possible presence of synergies whose related mechanisms are discussed. The rate constant parameters derived by means of the two tested models were finally used to simulate the evolution of the conversion degree of each sample as a function of the temperature, thus leading to a satisfying agreement between measured and simulated data.

The overall performance of metal catalysts can be efficiently adjusted by modifying carbon carriers with different valence sulfur precursors. The wet impregnation technique successfully prepared carbon material carriers doped with varying sources of sulfur (Na₂SO₄, NaHSO₃, Na₂S·9H₂O). Palladium carbon catalysts doped with different sulfur precursors had been prepared with the aid of the liquid-phase reduction method of the selective hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN). The catalyst prepared for Na₂S·9H₂O as a precursor has excellent performance, and the selectivity for o-CAN is more than 99.9% at 100% conversion. In addition, the characterization results show that with the decrease of S valence, the electronic effect between S and Pd increases, and the outer electron shift of Pd increases, which reduces the adsorption and dissociation ability of Pd to hydrogen, resulting in excellent selectivity. The effects provided a good idea for the hydrogenation of o-CNB and a different point of view on sulfur doping in a variety of hydrogenation reactions.

A new magnetic nanocomposite chitosan/EDTA/CeZnO (MEC-CeZnO) is synthesized as an efficient and eco-friendly bio-compound for the removal of chromium Cr(VI) metal ions and phenol organic matters from aqueous solutions. Nanocomposites are characterized using field emission scanning electron microscope, energy dispersive X-ray spectroscopy, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, diffuse reflection spectroscopy, and PL methods. The reduction rate of Cr(VI) ions and phenol degradation is evaluated under various experimental conditions, separately and simultaneously. The average pore diameter and specific surface of MEC-CeZnO nanocomposite are obtained 50 nm and 210 m²·g^-1 respectively, which suggest the successful synthesis of the nanocomposite because of the increased surface area and reduced pores in comparison to previous studies. Moreover, the best Cr(VI) and phenol reduction efficiencies are 98% and 92% at 180 min of retention time, both following the Langmuir-Hinshelwood first-order kinetics. The mechanisms of Cr(VI) and phenol removal from aqueous solutions involved Cr(VI) reduction, phenol oxidation, and adsorption. Examining the reusability of MEC-CeZnO showed that both degradation and recovery capacity is stable in 5 cycles.

Heavy metal (HM) pollution is a serious environment problem. Recovering HM from industrial wastewater by efficient adsorbents is a sustainable method due to recycling HM and acquiring reusable water. However, popular efficient adsorbents are usually expensive or non-reusable. In this paper, methods of efficient HM recycling and water reuse from industrial wastewater were developed using efficient adsorbents, new polyphenylene sulfide derivatives, which are recyclable and stable in an acidic, alkaline or oxidative aqueous solution. Moreover, they can efficiently and quickly adsorb HM ions. The maximum adsorption capacities of these adsorbents for HM ions are at the range from 51.3-184.2 mg·g^-1. The adsorption equilibrium times of them for HM ions are at the range from 10 to 80 min. Therefore, this paper suggests sustainable methods of HM recovery and water reuse from industrial wastewater.

Layered assembled membranes of 2D leaf-like zeolitic imidazolate frameworks (ZIF-L) nanosheets have received great attention in the field of water treatment due to the porous structure and excellent antibacterial ability, but the dense accumulation on the membrane surface and the low permeate flux greatly hinder their application. Herein, we synthesized mHNTs (modified halloysite nanotubes)/ZIF-L nanocomposites on modified mHNTs by in situ growth method. Interestingly, due to the different size of mHNTs and ZIF-L, mHNTs were packed in ZIF-L nanosheets. The hollow mHNTs provided additional transport channels for water molecules, and the accumulation of the ZIF-L nanosheets was decreased after assembling mHNTs/ZIF-L nanocomposites into membrane by filtration. The prepared mHNTs/ZIF-L membrane presented high permeate flux (59.6 L·m^-2·h^-1), which is 2-4 times of the ZIF-L membranes (14.8 L·m^-2·h^-1). Moreover, mHNTs/ZIF-L membranes are intrinsically antimicrobial, which exhibit extremely high bacterial resistance. We provide a controllable strategy to improve 2D ZIF-L assembles, and develops novel membranes using 2D package structure as building units.

The concentration and velocity fields of two refractive index matched miscible shear-thinning fluids in a lid-driven cavity were investigated by using planar laser-induced fluorescence and particle image velocimetry, as well by computational fluid dynamics. Quantitative analyses show that the results obtained by flow simulations with the species transport model are in good agreement with the experimental results. The effects of different parameters were studied by using the intensity of segregation. For two fluids with the same rheological parameters, the relative amounts of liquids H₁/H and the power-law index n dominate the mixing process while the Reynolds number Re plays a marginal role. As for two fluids with density difference, buoyancy has significant influence on the mixing process. The dimensionless group Ar/Re (redefined such as to include shear thinning behavior) is proposed for assessing the effect of buoyancy and rheological properties on the mixing of miscible shear-thinning fluids.

Currently, polymer nanosponges have received extensive attention. However, developing new synthetic techniques for novel nanosponges remains a challenge. Furthermore, to date, composite nanosponge adsorbents based on waterborne polyurethane (WPU) and β-cyclodextrin (β-CD) have not been reported. Herein, a novel green method, ion condensation method, was developed in this study for the preparation of polymer nanosponge adsorbents for efficient removal of dyes from wastewater. Based on the principle of charge repulsion between nanoparticles to maintain emulsion stability, waterborne polyurethane/β-cyclodextrin composite nanosponges (WPU-x,y) were prepared by coagulating the emulsions synthesized from 2,2-dimethylolpropionic acid, polypropylene glycol and hexamethylene diisocyanate as raw materials in a mixture of hydrochloric acid and anhydrous ethanol. The structure and appearance of WPU-x,y were characterized by attenuated total reflectance Fourier transform infrared spectroscopy, thermal gravimetric analyzer, scanning electron microscope and mercury intrusion porosimetry. The adsorption capacity of WPU-x,y was tested by parameters such as cross-linking degree, β-CD dosage, contact time, initial dye concentration and pH value. The study found that WPU-4,4.62 had the best adsorption effect on methylene blue (MB), the maximum removal rate was 93.42%, and the maximum adsorption capacity was 136.03 mg·g^-1. Moreover, the Sips isotherm and pseudo-second-order-model were suitable for MB adsorption. Therefore, this study provides some perspectives for the fabrication of nanosponge adsorbents.

Phenolic wastewater is one of the priorities in the field of wastewater treatment, which poses a serious threat to the human health and nature environment. In this paper, cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium oleate (NaOL) microemulsions were utilized to extract phenol from the wastewater. The optimal extraction factors were investigated by exploring the effects of microemulsion composition ratio and extraction conditions on the phenol extraction performance. Furthermore, the enhanced extraction mechanism of phenol by cations microemulsions is illustrated by studying the extraction process of cationic and anionic microemulsions in the extraction of phenol. The optimum components were obtained: surfactant concentration of 0.2 mol·L^-1, isoamyl alcohol volume of 30%, internal aqueous phase concentration of CTAB microemulsion of 0.05 mol·L^-1, and internal aqueous phase concentration of NaOL microemulsion of 0.09 mol·L^-1. The extraction efficiencies were 96.44% and 82.0% when using CTAB and NaOL microemulsions under optimal conditions (water-emulsion ratio of 5, contact time of 9 min, extraction temperature of 298.15 K, and pH of 9), confirming the enhanced extraction of phenol by CTAB cationic microemulsion. It was analyzed that the enhanced extraction of CTAB microemulsion was due to the electrostatic adsorption of cations with phenol root ions.

Selective epoxidation of olefins is an important field in chemical industry. In this work, we developed a new phosphotungstic acid catalyst {[(C₈H₁₇)(CH₃)₂N]₂(CH₂)₃}_1.5{PO₄[WO(O₂)₂]₄} with long carbon chain and biquaternary ammonium cation. Cyclohexene could be epoxidized to cyclohexene oxide in 96.3% conversion and 98.2% selectivity. The catalyst type, solvent type, catalyst loading, initial molar ratio, temperature, cycle performance and substrate extensibility were studied and optimized, the kinetic parameters about overall reaction and unit reaction were also calculated. Dynamic light scattering analysis was carried out to explain the different catalytic performance between catalysts with different carbon chain length. This novel catalyst and the corresponding dynamics and mechanism study could probably help the industrial application on the epoxidation of cyclohexene with H₂O₂.

Globally, the efficient utilization of polymer wastes is one of the most important issues for current sustainable development topics. Herein, a green and efficient low-temperature combustion approach is proposed to deal with polymer wastes and recover heat energy, simultaneously alleviating the environment and energy crisis. Non-noble metal oxides (Al₂O₃, Fe₂O₃, NiO₂, ZrO₂, La₂O₃ and CeO₂) were prepared, characterized and screened to boost the low-temperature combustion of polyethylene waste at 300 ℃ in air. The mass change, heat release and CO formation were studied in details and employed to evaluate the combustion rate and efficiency. It was found that CeO₂ significantly enhanced the combustion rate and efficiency, which was respectively 2 and 7 times that of non-catalytic case. An interesting phenomenon was observed that the catalytic performance of CeO₂ in polyethylene low-temperature combustion was significantly improved by the 7-day storage in the room environment or water treatment. XPS analysis confirmed the co-existence of Ce³⁺ and Ce⁴⁺ in CeO₂, and the 7-day storage and water treatment promoted the amount of Ce³⁺, which facilitated the formation of the oxygen vacancies. That may be the reason why CeO₂ exhibited excellent catalytic performance in polyethylene low-temperature combustion.

The work herein employed a rotating packed bed (RPB) to intensify the sulfonation process of 1,4-diaminoanthraquinone leuco (DL) in an attempt to improve the yield of the product 1,4-diaminoanthraquinone-2-sulfonic acid (DSA). First, the effects of operating conditions in a stirred tank reactor (STR), including stirring speed, chlorosulfonic acid/DL molar ratio (η), solvent/DL mass ratio (ζ), reaction temperature and dropping speed of chlorosulfonic acid, on the yield of DSA were investigated. The yield of DSA can reach 87.34% under the optimal operating conditions: stirring speed of 500 r·min^-1, η of 4.5, ζ of 7, reaction temperature of 150 ℃, dropping speed of 0.61 ml·min^-1. In addition, the kinetics of the sulfonation process via the shrinking core model revealed that the reaction is controlled by diffusion via a product layer under the reaction temperature of 140 ℃. Furthermore, the RPB was employed to intensify the mass transfer between liquid and solid phases during the sulfonation reaction process. The results showed that the DSA yield of 92.69% obtained by RPB was 5.35% higher than that by STR, indicating that RPB can significantly intensify the mass transfer in the liquid-solid phase sulfonation reaction process.

The methanolysis of amides, which is widely employed in the synthetic organic chemistry, hardly occurs under mild conditions. To safely and controllably intensify the methanolysis reaction with high-temperature and high-pressure environment, a continuous tubular reaction technology is developed, whose space-time yield is over twice of that of the conventional batch reaction. The methanolysis of acetanilide is selected as the representative reaction, and the influences of temperature, pressure, reactant and catalyst concentration, and residence time on the reaction performances are systematically investigated. Taking the advantages of precise temperature and reaction time control by the tubular reactor, the kinetics of acetanilide methanolysis are determined and compared to the kinetics of acetanilide hydrolysis reaction. The tubular reaction method is also employed to test a variety of other amides to show the effects of substituents, steric hindrance, and alkalinity on the reaction rate of methanolysis.

The hydrodynamic study of the liquid film around Taylor bubbles in slug flow has great significance for understanding parallel flow and interaction between Taylor bubbles. The prediction models for liquid film thickness mainly focus on stagnant flow, and some of them remain inaccurate performance. However, in the industrial process, the slug flow essentially is co-current flow. Therefore, in this paper, the liquid film thickness is studied by theoretical analysis and experimental methods under two conditions of stagnant and co-current flow. Firstly, under the condition of stagnant flow, the present work is based on Batchelor's theory, and modifies Batchelor's liquid film thickness model, which effectively improves its prediction accuracy. Under the condition of co-current flow, the prediction model of average liquid film thickness in slug flow is established by force and motion analysis. Taylor bubble length is introduced into the model as an important parameter. Dynamic experiments were carried out in the pipe with an inner diameter of 20 mm. The liquid film thickness, Taylor bubble velocity and length were measured by distributed ultrasonic sensor and intrusive cross-correlation conductivity sensor. Comparing the predicted value of the model with the measured results, the relative error is controlled within 10%.

The effects of sulfuric acid-associated mechanical pretreatment on the hydrolysis behavior of pine sawdust were investigated in this study. Sulfuric acid could act as an acidic catalyst to depolymerize holocellulose through cleavage of the glycosidic bonds, the dissociation energies of which were supplied by the impact of a ball on pine sawdust, during milling. The destruction of glycosidic and hydrogen bonds in pine sawdust resulted in a decrease of crystallinity and an increase of water solubility. The sulfuric acid could promote the hydrolysis of holocellulose and its hydrolysis products. It also destroyed the chemical linkages between holocellulose and lignin during ball milling. The cleavage of chemical linkages with holocellulose made lignin more difficult to hydrolyze in subcritical water, and higher activation energy was needed to hydrolyze pretreated pine sawdust at higher reaction temperatures. It also led to the formation of glucose char and aromatic-linked polymer char from the hydrolysis products of holocellulose.

In this paper, an improved computational fluid dynamic (CFD) model for gas-liquid flow in bubble column was developed using the one-equation Wary-Agarwal (WA) turbulence model coupled with the population balance model (PBM). Through 18 orthogonal test cases, the optimal combination of interfacial force models, including drag force, lift force, turbulent dispersion force. The modified wall lubrication force model was proposed to improve the predictive ability for hydrodynamic behavior near the wall of the bubble column. The values simulated by optimized CFD model were in agreement with experimental data, and the errors were within ±20%. In addition, the axial velocity, turbulent kinetic energy, bubble size distribution, and the dynamic characteristic of bubble plume were analyzed at different superficial gas velocities. This research work could provide a theoretical basis for the extension of the CFD-PBM coupled model to other multiphase reactors..

The solubility of 2,3,4-trichloro-1,5-dinitrobenzene (TCDNB) was measured by a laser dynamic method over the temperature range from 278.15 K to 323.15 K under 0.1 MPa in fifteen mono-solvents (methanol, ethanol, isopropanol, n-butanol, toluene, dichloromethane, chloroform, tetrachloromethane, 1,2-dichloroethane, acetone, ethyl acetate, acetonitrile, N-methylpyrrolidone (NMP), N,N-dimethylformamide dimethyl sulfoxide (DMF), dimethyl sulfoxide (DMSO). The solubility of TCDNB could be increased with increasing temperature in fifteen mono-solvents. TCDNB solubility is in the following order at 298.15 K: NMP>DMF>DMSO>toluene>acetone>ethyl acetate>dichloromethane>1,2-dichloroethane>chloroform>acetonitrile>tetrachloromethane>methanol>ethanol>n-butanol>isopropanol. The KAT-LSER model was used to investigate the solvent effect, which revealed that the hydrogen bond acidity of solvents has a greater effect on TCDNB solubility. The van't Hoff model, the modified Apelblat model, the λh model, and the non-random two liquid (NRTL) model were used to correlate the solubility of TCDNB. The calculated solubility data agreed well with the experimental data, and the modified Apelblat model fit best. Furthermore, the van't Hoff and Gibbs equations were also used to calculate the dissolution thermodynamic properties of TCDNB in various solvents. TCDNB dissolution could be an enthalpy-driven, non-spontaneous, and endothermic process in fifteen mono-solvents. The determination and fitting solubility of TCDNB, as well as the calculation of its thermodynamic properties, would be critical in the purification and crystallization of its preparation process research.

A novel alpha function for Peng-Robinson equation of state was proposed and generalized with acentric factor and dipole moment for predicting thermodynamic properties of non-polar, weakly polar, and polar compounds. The parameters of new alpha function were fitted with vapor pressures of 70 compounds. Six different methods were investigated for the correlation of parameters of new alpha function and Heyen alpha function. The generalized new alpha function passed the consistency test. The results indicated that the predictive accuracy of generalized new alpha function and generalized Heyen alpha function was improved for the estimation of vapor pressure of 11 kinds of compounds, with the average relative deviations (ARDs) being 2.60% and 2.76%. The ARDs of the two generalized alpha functions were 2.04% and 2.09% for the enthalpy of vaporization. However, the generalized new alpha function and the other alpha functions had great deviations for the prediction of liquid volumes and isobaric heat capacities. The alpha function that was generalized with acentric factor and reduced dipole moment was more accurate than that was generalized with acentric factor, especially for the prediction of vapor pressure and enthalpy of vaporization of polar compounds.

Cascade refrigeration system (CRS) can meet a wider range of refrigeration temperature requirements and is more energy efficient than single-refrigerant refrigeration system, making it more widely used in low-temperature industry processes. The synthesis of a CRS with simultaneous consideration of heat integration between refrigerant and process streams is challenging but promising for significant cost saving and reduction of carbon emission. This study presented a stochastic optimization method for the synthesis of CRS. An MINLP model was formulated based on the superstructure developed for the CRS, and an optimization framework was proposed, where simulated annealing algorithm was used to evolve the numbers of pressure/temperature levels for all sub-refrigeration systems, and particle swarm optimization algorithm was employed to optimize the continuous variables. The effectiveness of the proposed methodology was verified by a case study of CRS optimization in an ethylene plant with 21.89% the total annual cost saving.

The low temperature coal tar (CT) is taken as the raw material, and the extraction and column chromatography are used for detailed and accurate characterization in this paper. The n-heptane soluble fraction (CT-HS) and insoluble fraction (CT-HI) were obtained by n-heptane Soxhlet extraction. The extraction rate of CT-HS reached 92.79% (mass), which indicated that there are few heavy compounds in it. Further, different solvents (methylbenzene, benzene, ethyl acetate, methylbenzene-ethanol) were used to elute CT-HS by chromatographic column to obtain five fractions (saturates, aromatics, heteroatoms, phenolics and resins, named CT-SA, CT-AR, CT-HE, CT-PH, CT-RE, respectively). The yields of CT-SA, CT-AR, CT-HE, CT-PH, CT-RE are 42.12%, 10.43%, 2.19%, 9.50% and 6.63% (mass), respectively. Gas chromatography-mass spectrometry analysis of eluting components show that alkanes are the main components in CT, followed by polycyclic aromatics, and the corresponding fractions are CT-SA and CT-AR, respectively. The relative content of aliphatics in CT-SA is 76.93%, and the relative content of aromatics in CT-AR is 75.05%. This separation technology effectively separates and enriches different components in CT, and the activation energy required for the pyrolysis process of a single eluting fraction is lower than that of CT, which is expected to provide an important reference for the separation, analysis and conversion of complex oil products such as coal-oil co-processing products, coal tar and other complex heavy carbon oil products.

Silica aerogels have promising applications in thermal insulation, but their flammability and reaction mechanisms have rarely been investigated. The pyrolysis kinetics and thermodynamics of hydrophobic silica aerogels under N₂ environment were studied. The kinetic and thermodynamic parameters were obtained by three model-free methods. Based on the calculated kinetic parameters, the pyrolysis mechanism of silica aerogels was discussed by the master plots method. The results indicate that the reactions of the whole pyrolysis phase can be characterized by a random nuclear model. In addition, FTIR test results show that the volatile products of silica aerogel pyrolysis are mainly hydrocarbons generated by the decomposition of hydrophobic groups (methyl groups) on the surface. Finally, the effects of pyrolysis on the properties of silica aerogels Finally, the effects of pyrolysis on the properties of silica aerogels were investigated based on the analysis results of SEM, specific surface area, pore size distribution, X-ray diffraction, XPS and infrared spectroscopy.

At present, only a single modification method is adopted to improve the shortcomings of erythritol (ET) as a phase change material (PCM). Compared with a single modification method, the synergistic effect of multiple modification methods can endow ET with comprehensive performance to meet the purpose of package, supercooling reduction, and enhancement of thermal conductivity. In this work, we innovatively combine graphene oxide (GO) nanosheet modified melamine foam (MF) and polyaniline (PANI) to construct a novel ET-based PCM by blending and porous material adsorption modification. PANI as the nucleation center can enhance the crystallization rate, thereby reducing the supercooling of ET. Meanwhile, GO@MF foam can not only be used as a porous support material to encapsulate ET but also as a heat conduction reinforcement to improve heat storage and release rate. As a result, the supercooling of GO@MF/PANI@ET (GMPET) composite PCM decreases from 91.2 ℃ of pure ET to 57.9 ℃ and its thermal conductivity (1.58 W·m^-1·K^-1) is about three times higher than that of pure ET (0.57 W·m^-1·K^-1). Moreover, after being placed at 140 ℃ for 2 h, there is almost no ET leakage in the GMPET composite PCM, and the mass loss ratio is less than 0.75%. In addition, the GMPET composite PCM displays a high melting enthalpy of about 259 J·g^-1 and a high initial mass loss temperature of about 198 ℃. Even after the 200th cycling test, the phase transition temperature and the latent heat storage capacity of the GMPET PCM all remain stable. This work offers an effective and promising strategy to design ET-based composite PCM for the field of energy storage.

Biomass chemical looping gasification technology is one of the essential ways to utilize abundant biomass resources. At the same time, dimethyl carbonate can replace phosgene as an environment-friendly organic material for the synthesis of polycarbonate. In this paper, a novel system coupling biomass chemical looping gasification with dimethyl carbonate synthesis with methanol as an intermediate is designed through microscopic mechanism analysis and process optimization. Firstly, reactive force field molecular dynamics simulation is performed to explore the reaction mechanism of biomass chemical looping gasification to determine the optimal gasification temperature range. Secondly, steady-state simulations of the process based on molecular dynamics simulation results are carried out to investigate the effects of temperature, steam to biomass ratio, and oxygen carrier to biomass ratio on the syngas yield and compositions. In addition, the main energy indicators of biomass chemical looping gasification process including lower heating value and cold gas efficiency are analyzed based on the above optimum parameters. Then, two synthesis stages are simulated and optimized with the following results obtained: the optimal temperature and pressure of methanol synthesis stage are 150 ℃ and 4 MPa; the optimal temperature and pressure of dimethyl carbonate synthesis stage are 140 ℃ and 0.3 MPa. Finally, the pre-separation-extraction-decantation process separates the mixture of dimethyl carbonate and methanol generated in the synthesis stage with 99.11% purity of dimethyl carbonate. Above results verify the feasibility of producing dimethyl carbonate from the perspective of multi-scale simulation and realize the multi-level utilization of biomass resources.

It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas hydrate. However, its mechanism is still not well understood yet. In this research, structure-II (sII) hydrate is synthesized using a methane-propane gas mixture with an initial mole ratio of 99:1, and it is found that large (5¹²6⁴) cages are co-occupied by multiple gases based on the rigid structure analysis of neutron diffraction data. The first principles calculation and molecular dynamics simulation are conducted to uncover the molecular mechanism for sII methane-propane hydrate formation, revealing that the presence of propane inhibits the formation of structure-I (sI) hydrate but promotes sII hydrate formation. The results help to understand the accumulation mechanism of natural gas hydrate and benefit to optimize the condition for gas storage and transportation in hydrate form.

In application, lithium-ion cells undergo expansion during cycling. The mechanical behavior and the impact of external stress on lithium-ion battery are important in vehicle application. In this work, 18 Ah high power commercial cell with LiNi_0.5Co_0.2Mn_0.3O₂/graphite electrode were adopted. A commercial compress machine was applied to monitor the mechanical characteristics under different stage of charge (SOC), lifetime and initial external force. The dynamic and steady force was obtained and the results show that the dynamic force increases as the SOC increasing, obviously. During the lifetime with high power driving mode, different external force is shown to have a great impact on the long-term cell performance, with higher stresses result in higher capacity decay rates and faster impedance increases. A proper initial external force (900 N) provides lower impedance increasing. Postmortem analysis of the cells with 2000 N initial force suggests a close correlation between electrochemistry and mechanics in which higher initial force leads to higher direct current internal resistance (DCIR) increase rate. In addition, for the cell with higher external force, deformation of the cathode and thicker solid electrolyte interface (SEI) film on the surface of anode and separator are observed. Porosity reduction and closure was also verified after cycles which is an obstacle to the lithium ion transferring. The largest cause of the observed capacity decline was the loss of active lithium through autopsy analysis. In addition, for the cell with higher external force, deformation of the cathode and thicker SEI film on the surface of anode and separator are observed. Porosity reduction and closure was also verified after cycles which is an obstacle to the lithium ion transferring. The largest cause of the observed capacity decline was the loss of active lithium through autopsy analysis.

Horizontal gas-liquid two-phase flows widely exist in chemical engineering, oil/gas production and other important industrial processes. Slug flow pattern is the main form of horizontal gas-liquid flows and characterized by intermittent motion of film region and slug region. This work aims to develop the ultrasonic Doppler method to realize the simultaneous measurement of the velocity profile and liquid film thickness of slug flow. A single-frequency single-channel transducer is adopted in the design of the field-programmable gate array based ultrasonic Doppler system. A multiple echo repetition technology is used to improve the temporal-spatial resolution for the velocity profile. An experiment of horizontal gas-liquid two-phase flow is implemented in an acrylic pipe with an inner diameter of 20 mm. Considering the aerated characteristics of the liquid slug, slug flow is divided into low-aerated slug flow, high-aerated slug flow and pseudo slug flow. The temporal-spatial velocity distributions of the three kinds of slug flows are reconstructed by using the ultrasonic velocity profile measurement. The evolution characteristics of the average velocity profile in slug flows are investigated. A novel method is proposed to derive the liquid film thickness based on the instantaneous velocity profile. The liquid film thickness can be effectively measured by detecting the position and the size of the bubbles nearly below the elongated gas bubble. Compared with the time of flight method, the film thickness measured by the Doppler system shows a higher accuracy as a bubble layer occurs in the film region. The effect of the gas distribution on the film thickness is uncovered in three kinds of slug flows.

For a long time, China's regional water resource imbalance has restricted the development of coal chemical industry, and it is imperative to achieve zero liquid discharge (ZLD). Therefore, the game relationship between technical indicators, costs and emissions in ZLD process of fixed-bed coal gasification wastewater treatment process should be explored in detail. According to the accurate model, the simulation for ZLD of fixed-bed coal gasification wastewater treatment process is established, and this process is assessed from the perspective of thermodynamics, economy, and environment. The total energy consumption of ZLD process before optimization is 4.032×10⁸ W. The results of exergy analysis show exergy destruction of ZLD process is 94.55%. For economic and environmental results, the total annual cost is 1.892×10⁷ USD·a^-1 and the total environmental impact is 4.782×10^-8. The total energy consumption of the optimal six-step ZLD process based on multi-objective optimization is 4.028×10⁸ W. The CO₂ content in the treated wastewater is 0.1%. This study will have an important role in promoting the establishment of the ZLD process for coal chemistry industry.

The development of novel absorbents is essential for SO₂ removal. In this study, a novel ionic liquid (IL, [BHEP][HSO₄]) was prepared, and water was selected as the co-solvent. The density and viscosity of aqueous [BHEP][HSO₄] were measured and the SO₂ absorption performance was systematically investigated. Furthermore, the thermodynamic properties of SO₂ in aqueous [BHEP][HSO₄] were calculated. Additionally, the mechanism of SO₂ absorption in aqueous [BHEP][HSO₄] was confirmed using Fourier-transform infrared and nuclear magnetic resonance spectroscopy. It showed that [BHEP][HSO₄] absorbed 0.302 g·g^-1 (g SO₂/g IL) at an SO₂ partial pressure of 2000 μl·L^-1 at 303.2 K, and the SO₂ desorption enthalpy was -39.63 kJ·mol^-1. The mechanistic study confirmed the chemical absorption of SO₂ in aqueous [BHEP][HSO₄].