查看更多>>摘要：A new continuous catalytic reforming model was configured by using a molecule-based reactor module.The model was based on the Sinopec Research Institute of Petroleum Processing Co.,Ltd.continuous catalytic reformer full model,and was reduced to a size of 157 naphtha molecules(C1-C12)that underwent 764 reactions.The new model inherited the advantages of the original model,and had better solving performance and flexibility owing to support by the Aspen HYSYS environment.Typical commercial plant data were selected for model validation,which showed advantages in the accuracy of detailed predictions and the range of its application.In addition,the solving time was reduced from minutes to seconds.Therefore,the simplified model proved to be feasible for industrial application.
Yang FengjingLuo NianjunChen YuxiangLiu Chuanlei...
109-121页
查看更多>>摘要：Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial production of 3-hydroxypropionic acid.However,the relevant literature primarily focuses on the experimental aspects of catalyst screening and exploring reaction conditions,with few accurate descriptions of the reaction kinetics and determination of the reaction mechanism.Here,we combined kinetics experiments and theoretical calculations to elucidate the kinetics and mechanism of acrylic acid hydration on a resin catalyst.The pseudo-homogeneous model,and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel(ER)heterogeneous models were used to explain the experimental kinetics data.The ER model can explain the experimental data very well,suggesting strong adsorption of acrylic acid on the surface of the resin catalyst.Furthermore,density functional theory calculations show that the hydration follows a stepwise,rather than a concerted,reaction pathway.The present study provides theoretical insights into the reaction mechanism and kinetics,filling the gap in our understanding of the reaction on a fundamental level.
查看更多>>摘要：Considering the multivariable and fractional-order characteristics of proton exchange membrane fuel cells(PEMFCs),a fractional-order subspace identification method(FOSIM)is proposed in this paper to establish a fractional-order state space(FOSS)model,which can be expressed as a multivariable configuration with two inputs,hydrogen-flow rate and stack current,and two outputs,cell voltage and power.Based on this model,a novel constrained optimal control law named the Hildreth model predictive control(H-MPC)strategy is created,which employs a Hildreth quadratic programming algorithm to adjust the output power of fuel cells through adaptively regulating hydrogen flow and stack current.dSPACE semi-physical simulation results demonstrate that,compared with proportional-integral-derivative and quadratic programming MPC(QP-MPC),the proposed H-MPC exhibits better tracking ability and strong robustness against variations of PEMFC power.
查看更多>>摘要：Samples(25500)were collected from a selective catalytic reduction(SCR)denitrification system in a fluid catalytic cracking unit and preprocessed using the quartile method and the K-nearest neighbors interpolation method to remove outliers.Using the Pearson correlation coefficient and LightGBM feature score method,13 key operational variables were identified and used to establish a model to predict outlet nitrogen oxide(NOx)concentration in an SCR system with backpropagation neural network,long short-term memory(LSTM)and LSTM-attention fully connected(FC)model,respectively.The LSTM-attention FC model showed better accuracy and generalization capability compared with other models.Its mean square error,mean absolute error,and coefficient of determination on the training and test datasets were 11.32 and 12.51,3.65%and 3.97%,and 0.96 and 0.94,respectively.Furthermore,a combination of the LSTM-attention FC model with a genetic algorithm used to optimize four feature variables including ammonia pressure compensation,inlet pressure,gas inlet upper temperature,and outlet ammonia concentration.The outlet NOx concentration could be controlled below 80±3 mg/m3,and the ammonia slip concentration could be controlled below 0.1 mg/m3,demonstrating that the optimization model can provide effective guidance for reducing NOx emissions and ammonia slip of SCR systems.
查看更多>>摘要：A three-lumping Langmuir-Hinshelwood kinetic model was established based on the structures and reactivities of sulfur compounds.This model described the ultra-deep hydrodesulfurization(UDHDS)performance of diesel,reducing sulfur content from 10000 μg/g to less than 10 μg/g,with experimental and predicted data showing a discrepancy of less than 10%.The diesel UDHDS reaction was simulated by combining the mass transfer,reaction kinetics model,and physical properties of diesel.The results showed how the concentrations of H2S,hydrogen,and sulfur in the gas,liquid,and solid phases varied along the reactor length.Moreover,the study discussed the effects of each process parameter and impurity concentrations(H2S,basic nitrogen and,non-basic nitrogen)on diesel UDHDS.
查看更多>>摘要：This study prepared four types of ionic liquid-modified polypyrrole(IL-modified PPy)as conductive additives and investigated their tribological performance and conductivity in polytetrafluoroethylene lubricating grease.The results indicated that IL-modified PPy effectively enhanced the anti-wear performance and conductivity of the base grease.Among the additives,1-octyl-3-methylimidazolium tetrafluoroborate([OMIm][BF4])modified PPy showed superior performance compared to the other three additives,with the best effect observed at a mass fraction of 0.5%.X-ray photoelectron spectroscopy analysis revealed that IL-modified PPy forms a stable friction chemical film during the friction process,effectively enhancing the lubrication performance and conductivity of the base grease.This indicates broad potential applications in the field of conductive lubrication.
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