查看更多>>摘要：The key reason for SO2 formation during the production of a residue hydrogenation catalyst support was identified and subsequent emission reduction solutions were then investigated and verified systematically.The results demonstrated that carbon-containing organic materials,including sesbania powder and cellulose,did not completely decompose over the temperature range of 350-600 ℃ during the heating stage of the calcination process,but rather underwent a condensation reaction within the same temperature range to form carbon-containing species with a lower ratio of hydrogen to carbon and a higher condensation degree,which promoted the decomposition of sulfate to form SO2.Systematic experimental work revealed that three different measures,i.e.,applying the staged calcination method,reducing the heating rate,and increasing the air flow rate,during the calcination process could all achieve the effect of reducing SO2 emissions.
查看更多>>摘要：Oil and water separation has always been a top priority in the oil industry.In this study,a series of hyperbranched fluorinated polyamine-amine polymers(HFPA1-5)were synthesized directly using an improved"one-pot method."The highly active fluorinated p-trifluoromethylaniline was used as the core raw material,while diethylenetriamine and methyl acrylate were used as the chain segment.A hyperbranched fluorine-containing polyamine-amine demulsifier(NHFPA6)was obtained through nano-grafting copolymerization of HFPA5.To enhance the demulsification and dehydration performance,the copolymerized HFPA6 was modified and combined.Then,the effects of the combination ratio,demulsifier concentration,demulsification time,and demulsification temperature on the demulsification effect were investigated.The results revealed that a combination ratio of DE-401:NHFPA6=1:1,a demulsification temperature of 50 ℃,a demulsification time of 60 min,and a demulsifier concentration of 150 mg/L yielded a dehydration rate as high as 99.80％.A response surface optimization design of demulsification conditions was performed.The model verified that the optimal demulsification conditions were 50 ℃,300 mg/L,and 90 min.However,considering the economic benefits of factories,it is more favorable to select demulsification conditions with a shorter time and lower concentration when the dehydration standard is met.Therefore,the demulsification conditions were selected as 50 ℃,150 mg/L,and 60 min.Compared to existing demulsifiers,the demulsifier developed in this study exhibits a lower demulsification temperature and higher demulsification efficiency.
查看更多>>摘要：In this study,the separation and coalescence of oil-in-water emulsions are explored in an ultrasonic field using the lattice Boltzmann method.By simulating the propagation of ultrasonic waves,this study focuses on examining the effects of acoustic wave frequency,the ratio of oil to water components,and the aspect ratio of the boundary on the emulsification and separation processes of oil-water mixtures.The following conclusions are drawn.① Frequency affects the speed of oil droplet separation,leading to an increase in droplet size over time.Larger droplets are found near the source,while smaller droplets are distributed throughout the wave web.② As the boundary aspect ratio increases,the emulsification efficiency of the droplets weakens,and the system takes longer to stabilize.③ Emulsions with a higher component of oil can better resist acoustic waves.④ At the same acoustic frequency,longer wavelength ultrasonic fields promote the formation of uniformly distributed,smaller oil droplets,which is beneficial to the storage of emulsions.These numerical simulation results offer insights for optimizing conditions for oil-in-water separation and serve as a numerical reference for the study of oil-in-water emulsion separation in ultrasonic environments.
查看更多>>摘要：Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirmed that the damage was caused by erosion-corrosion(E-C).Numerical and experimental methods were applied to investigate the E-C mechanism in the air cooler.Computational fluid dynamics(CFD)was used to calculate the hydrodynamic parameters of the air cooler.The results showed that there was a biased flow in the air cooler,which led to a significant increase in velocity,turbulent kinetic energy and wall shear within 0.2 m of the tube entrance.A visualization experiment was then performed to determine the principles of migration and transformation of multiphase flow in the air cooler tubes.Various flow patterns(pure droplet flow,mist flow,and annular flow)and their evolutionary processes were clearly depicted experimentally.The initiation mechanism and processes leading to the development of E-C in the air cooler were also determined.This study provided a comprehensive explanation for the E-C failures that occur in air coolers during operation.
查看更多>>摘要：Hydroconversion of coal tar to produce aromatic hydrocarbons(BTX)represents a crucial strategy for the high-value hierarchical utilization of coal.This study focused on the hydrocracking of hydrorefined products derived from coal tar to enhance the production of benzene,toluene,and xylene(BTX).Various reaction conditions,including reaction temperature,hydrogen pressure,space velocity,and hydrogen-to-oil volume ratio,were systematically explored to optimize BTX yields while also considering the process's economic feasibility.The results indicate that increasing the reaction temperature from 360 ℃ to 390 ℃ significantly favors the production of BTX,with yields increasing from 21.42％to 41.14％.Similarly,an increase in hydrogen pressure from 4 MPa to 6 MPa boosts BTX production,with yields rising from 36.31％to 41.14％.Reducing the space velocity from 2 h-1 to 0.5 h-1 also favors the BTX production process,with yields increasing from 37.96％to 45.13％.Furthermore,raising the hydrogen-to-oil volume ratio from 750 to 1500 improves BTX yields from 41.61％to 45.44％.Through economic analysis,the optimal conditions for BTX production were identified as a reaction temperature of 390 ℃,hydrogen pressure of 5-6 MPa,space velocity of 1 h,and hydrogen-to-oil volume ratio of 1000,achieving a BTX yield of 43.73％.This investigation highlights the importance of a holistic evaluation of hydrocracking conditions to optimize BTX production.Furthermore,the findings offer valuable insights for the design and operation of industrial hydrocracking processes aimed at efficiently converting coal tar-derived hydrorefined feedstock into BTX.
查看更多>>摘要：Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges related to inadequate mass transfer and a high pressure drop caused by the non-uniform void fraction distribution.To enhance the overall performance of fixed beds,the impact of different packing configurations on performance was investigated.Experimental and simulation methods were used to investigate the fluid flow and mass transfer performances of various packed beds under different flow rates.It was found that structured beds exhibited a significantly lower pressure drop per unit length than conventional packed beds.Furthermore,the packing configurations had a critical role in improving the overall performance of fixed beds.Specifically,structured packed beds,particularly the H-2 packing configuration,effectively reduced the pressure drop per unit length and improved the mass transfer efficiency.The H-2 packing configuration consisted of two parallel strips of particles in each layer,with strips arranged perpendicularly between adjacent layers,and the spacing between the strips varied from layer to layer.
查看更多>>摘要：The composition of base oils affects the performance of lubricants made from them.This paper proposes a hybrid model based on gradient-boosted decision tree(GBDT)to analyze the effect of different ratios of KN4010,PAO40,and PriEco3000 component in a composite base oil system on the performance of lubricants.The study was conducted under small laboratory sample conditions,and a data expansion method using the Gaussian Copula function was proposed to improve the prediction ability of the hybrid model.The study also compared four optimization algorithms,sticky mushroom algorithm(SMA),genetic algorithm(GA),whale optimization algorithm(WOA),and seagull optimization algorithm(SOA),to predict the kinematic viscosity at 40 ℃,kinematic viscosity at 100 ℃,viscosity index,and oxidation induction time performance of the lubricant.The results showed that the Gaussian Copula function data expansion method improved the prediction ability of the hybrid model in the case of small samples.The SOA-GBDT hybrid model had the fastest convergence speed for the samples and the best prediction effect,with determination coefficients(R2)for the four indicators of lubricants reaching 0.98,0.99,0.96 and 0.96,respectively.Thus,this model can significantly reduce the model's prediction error and has good prediction ability.
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