Development and Application of Castables for Ladle Nozzle of Electric Arc Furnace

The castables for ladle nozzle were developed using brown corundum as the main raw material and the right amounts of complex additives. The influence of several additives on the properties such as strength and permanent linear change of the samples was studied. The results showed that applying complex additives improved the strength and the volume stability of the castables greatly. The campaign of the castables for ladle nozzle has increased from about 40 heats to 70 heats.     

Performance Comparison of Different Separation Systems for H2 Recovery from Catalytic Reforming Unit Off‐Gas Streams

The performance of pressure swing adsorption (PSA), membrane separation, and gas absorption systems for H₂ recovery from refinery off‐gas stream was studied by simulation‐based data. The PSA process was simulated using adsorbents of silica gel and activated carbon for removing heavy and light hydrocarbons. The mole fraction profiles of all components and the relationship between hydrogen purity and recovery as a function of feed pressure were examined. The solution‐diffusion model was applied for modeling and simulation of a one‐stage membrane process. The gas absorption process with a tower tray was simulated at sub‐zero temperature and the correlation between hydrogen purity and recovery as a function of tower pressure and temperature was evaluated at different solvent flow rates.     

Advances in Organic Liquid‐Gas Chemical Heat Pumps

Compared with inorganic chemical heat pumps (CHPs), organic liquid‐gas CHPs are more amenable to be run as a continuous process because the reactants and products can be fed or removed continuously. Therefore, increasing attention has been paid to investigations of CHPs using the organic liquid‐gas reaction system. Relevant research topics involved reaction catalyst, chemical reaction kinetics, reactive distillation, energy efficiency evaluation, economic analysis, etc. Nevertheless, the research on an organic liquid‐gas CHP system is still in the elementary stage. A detailed review on the current research status of catalyst‐assisted CHPs employing an organic liquid‐gas reaction system has been performed. Existing problems are identified and future research directions are proposed.     

对二甲苯装置加热炉余热回收分析

分析并探讨了对二甲苯装置加热炉余热回收利用情况,提出了增加余热回收系统、降低排烟温度、降低燃料中的硫含量等节能减排措施,以提高加热炉热效率,降低装置能耗。     

Modeling of Gas‐Solid Reactions: Kinetics,Mass and Heat Transfer,and Evolution of the Pore Structure

Mathematical models for simulating heterogeneous gas‐solid reactions must describe a complex set of physicochemical and thermal phenomena. These include the chemical reaction itself, at an interface whose area varies during the conversion, the transport of gaseous species by diffusion in the pores of the solid, whose size and number generally change in the course of reaction, diffusional transport in the layer of solid product, the evolution or consumption of heat by the reaction and its transport in the porous solid, etc. The present paper gives details of the equations employed to model each of these processes. Some computed results illustrate how increasingly sophisticated recent models describe the gradual obstruction of pores during reactions, such as the sulfation of lime, or the thermal effects related to the exothermic nature of the oxidation of zinc sulfide.     

Effect of Anode off‐gas Recycling on Reforming of Natural Gas for Solid Oxide Fuel Cell Systems

The effect of anode off‐gas recycling (AOGR) on the characteristic performance of a natural gas reformer equipped with a precious metal catalyst is investigated experimentally. The reformer is operated both with synthetic AOGR gas and in steam reforming (SR) conditions. The characteristic performance in SR and AOGR mode are compared with equilibrium, and it is found that equilibrium is more readily achieved in AOGR mode. The reformer is used for extended periods of time (100–1,000 h) in conditions where carbon formation is thermodynamically possible to measure any changes in characteristic performance. No significant change in the performance is observed due to carbon formation or catalyst deactivation. The reformer could be successfully implemented in a 10 kW SOFC system with an anode off‐gas recycling loop.     

TS3000控制系统在贮运厂火炬气回收中的应用

介绍了TS3000三重化冗余容错集成控制系统在火炬气回收装置压缩机机组综合控制系统的集成应用.该系统TRICON客错控制器是基于三重模件冗余(TMR)结构的现代化容错控制器,能确保火炬气回收装置安全、连续、稳定运行.     

Kinetic Modeling of the Gas Antisolvent Process for Synthesis of 5‐Fluorouracil Nanoparticles

Mathematical modeling for 5‐fluorouracil (5‐FU) nanoparticle synthesis via gas antisolvent (GAS) process was investigated. 5‐FU was precipitated from a dimethyl sulfoxide (DMSO) solution using CO₂ as antisolvent. The particle size was controlled by nucleation and growth rates, therefore, the kinetic modeling study is essential. Thermodynamic modeling was applied to determine optimal operating conditions for experimental 5‐FU synthesis. Kinetic parameters were evaluated by fitting the particle size distribution predicted by the model to experimental data. The experimental and modeling results indicated that the particle size decreased with increasing the antisolvent addition rate.     

Performance Evaluation and Parametric Optimization of a Proton Exchange Membrane Fuel Cell/heat‐driven Heat Pump Hybrid System

With the help of the current models of proton exchange membrane (PEM) fuel cells and three‐heat‐source heat pumps, a generic model of a PEM fuel cell/heat‐driven heat pump hybrid system is established, so that the waste heat produced in the PEM fuel cell may be availably utilized. Based on the theory of electrochemistry and non‐equilibrium thermodynamics, expressions for the efficiency and power output of the PEM fuel cell, the coefficient of performance and rate of pumping heat of the heat‐driven heat pump, and the equivalent efficiency and power output of the hybrid system are derived. The curves of the equivalent efficiency and power output of the hybrid system varying with the electric current density and the equivalent power output versus efficiency curves are represented through numerical calculation. The general performance characteristics of the hybrid system are analyzed. The optimally operating regions of some important parameters of the hybrid system are determined. The influence of some main irreversible losses on the performance of the hybrid system is discussed in detail. The advantages of the hybrid system are revealed.     

DFT and MP2 Study of Intermolecular Interaction of 5‐Aminotetrazole and Hydrazine: Enthalpy of Formation of Hydrazinium 5‐Aminotetrazolate in the Gas Phase

The tautomerism of all possible forms of 5‐aminotetrazole ( AT1 – AT7 ) in the gas phase and continuum solvent was studied theoretically. The calculations were separately performed at the MP2 and CAM‐B3LYP levels of theory, using the 6‐311++G(d,p) basis set. It was found that 5‐aminotetrazole in the 2H form ( AT1) is the most stable isomer in both the gas phase and in solution. In addition, the aggregation of various isomers of 5‐aminotetrazole with hydrazine was investigated in the gas phase and in solution. Finally, the standard enthalpy of formations of the different structures of hydrazinium 5‐aminotetrazolate was determined in the gas phase. Using the calculated standard enthalpy of formation of different structures of hydrazinium 5‐aminotetrazolate in the gas phase and considering their Boltzmann population ratios, a single value has been reported for the standard enthalpy of formation of hydrazinium 5‐aminotetrazolate considering all of the tautomers. The calculated values are in excellent agreement with the experimentally reported heat of formation for the hydrazinium 5‐aminotetrazolate.     

硫回收装置尾气处理系统氨法脱硫工艺的技术经济分析

神华宁煤集团400万t/a煤制油项目硫回收装置尾气处理系统采用氨法脱硫工艺。介绍了氨法脱硫工艺的工艺流程和工艺特点,并以传统的SCOT脱硫工艺为参照,进行了投资、消耗和产出等方面的技术经济分析。结果表明,氨法脱硫工艺具有工艺流程简单、便于操作维护等优点,在煤化工硫回收装置尾气脱硫领域具有良好的应用前景。     

基于人工神经网络的贫化电炉计算机监督控制系统研制及应用

将人工神经网络和经典控制技术有机结合,开发了贫化电炉计算机监督控制系统。采用前向多层人工神经网络学习出贫化电炉渣含钴与渣中Fe/SiO2关系模型,并优化出最佳Fe/SiO2;采用BP网络对产出物成分进行预测;采用改进的Hopfield网络对物料进行优化计算。优化结果用来修改现场控制器的设定参数;用现场模拟控制系统直接控制贫化电炉。     

Dynamic modeling and simulations of the behavior of a fixed‐bed reactor‐exchanger used for CO2 methanation

A multidimensional heterogeneous and dynamic model of a fixed‐bed heat exchanger reactor used for CO₂ methanation has been developed in this work that is based on mass, energy and momentum balances in the gas phase and mass and energy balances for the catalyst phase. The dynamic behavior of this reactor is simulated for transient variations in inlet gas temperature, cooling temperature, gas inlet flow rate, and outlet pressure. Simulation results showed that wrong‐way behaviors can occur for any abrupt temperature changes. Conversely, temperature ramp changes enable to attenuate and even fade the wrong‐way behavior. Traveling hot spots appear only when the change of an operating condition shifts the reactor from an ignited steady state to a non‐ignited one. Inlet gas flow rate variations reveal overshoots and undershoots of the reactor maximum temperature. © 2017 American Institute of Chemical Engineers AIChE J, 64: 468–480, 2018     

Comparative Evaluation of OpenFOAM® and ANSYS® Fluent for the Modeling of Annular Reactors

A three‐dimensional numerical model was solved for a turbulent incompressible steady flow and the discrepancies and similarities between the software OpenFOAM® and ANSYS® Fluent on the flow modeling were analyzed. The evaluation was performed for the meshing, setup, and simulation step of the modeling process. Outcomes were contrasted with experimental data to validate the fluid flow obtained with both softwares. With this aim, an experimental pulse‐response technique was applied to obtain the residence time distribution (RTD) curve to be compared with the RTD curves achieved from the modeling. Additionally, images of the tracer transport in the experimental reactor were taken, showing good agreement with the computational fluid dynamics (CFD) predictions.     

Prediction of Two‐Phase Frictional Pressure Drop for the Concurrent Gas and Newtonian Liquids Upflow through Packed Beds

Correlations were developed to predict frictional pressure drop for concurrent gas‐liquid upflow through packed beds covering all the three identified flow regimes, i.e. bubble flow, pulse flow and spray flow. The observation that the gas and liquid flow rates have different influences on the two‐phase pressure drop in different flow regimes, was taken into consideration in the development of these correlations. More than 600 experimental pressure drop data from the present study and literature covering a wide range in gas‐liquid systems, flow rates and column packing were used.     

Experimental and Theoretical Investigation of Double Gas Hydrate Formation in the Presence or Absence of Kinetic Inhibitors in a Flow Mini‐Loop Apparatus

Double gas hydrate formation in the presence or absence of kinetic inhibitors in a flow mini‐loop apparatus was investigated. For the prediction of the gas consumption rate during hydrate formation in this system, the rate equation based on the Kashchiev and Firoozabadi model for simple gas hydrate formation in a batch system was developed for double gas hydrate formation in a flow mini‐loop apparatus. To complete the theoretical evaluation of gas hydrate formation through the mini‐loop apparatus in the presence or absence of kinetic hydrate inhibitors (KHI), a laboratory flow mini‐loop apparatus was set up to measure the induction time for hydrate formation and the uptake rate when a gaseous mixture (such as 75 % C1/25 % C3, 25 % C1/75 % C3, 75 % C1/25 % i‐C4, and 25 % C1/75 % i‐C4) is contacted with water containing or not containing dissolved inhibitor under suitable temperature and pressure conditions. In each experiment, a water blend saturated with gas mixture was circulated up to the required pressure. The pressure was maintained at a constant value during the experimental runs by means of a required gas mixture make‐up. The effect of pressure on gas consumption during hydrate formation was investigated in the presence or absence of polyvinylpyrrolidone (PVP) and L ‐tyrosine as kinetic inhibitors at various concentrations. A good agreement was found between the predicted and experimental data in the presence or absence of KHI. The total average absolute deviation percents between the experimental and predicted values of gas consumption were found to be 16.4 and 17.5 % for the double gas hydrate formation in the presence or absence of the kinetic inhibitors, respectively.     

Cu/Ni‐Loaded CeO2‐ZrO2 Catalyst for the Water‐Gas Shift Reaction: Effects of Loaded Metals and CeO2 Addition

Two different types of metals (Cu and Ni) and the effect of CeO₂ addition to produce a CeO₂‐ZrO₂ co‐supporter were investigated through the water‐gas shift (WGS) reaction. It was found that the WGS activity could be enhanced with CeO₂ addition. At relatively high temperature, Ni‐loaded catalysts exhibited higher CO conversion while Cu‐loaded catalysts demonstrated better performance at low temperatures. The stability and yield of the CO₂ and H₂ products of the Cu catalysts were higher than those of the Ni catalysts. These results may be caused by an irreversible adsorption of CO on Ni and the reverse WGS reaction occurring on the Ni catalysts. In situ diffuse‐reflection infrared Fourier transform spectroscopy data suggests that the WGS mechanism likely proceeded via formate species.     

Study on the Curing Process and the Gelation of Epoxy/Anhydride System for No‐Flow Underfill for Flip‐Chip Applications

No‐flow underfill is used in the assembly of microelectronics to increase the productivity and to decrease the cost of the flip‐chip manufacturing. The curing process, especially the gelation of the no‐flow underfill, is essential for the yield and reliability of the flip‐chip assembly. A differential scanning calorimeter (DSC) and a stress rheometer are used to study the curing process of epoxy/anhydride system at different curing rates and different isothermal temperatures. The gel point is found when the storage modulus and the loss modulus of the resin measured by the rheometer equals to each other. The degree of cure (DOC) at gelation is calculated according to the results from DSC. The results indicate a strong dependence of the DOC at gelation on the heating rates and the curing temperatures. In order to further investigate the difference in the curing process at various heating rates, FTIR spectra of the resin are taken during curing. The change of different functional groups is recorded and compared. The results do not show a significant difference in the chemical structure at different heating rates. The early gelation at high heating rate/ high temperature can be caused by the structure difference in the epoxy network at the early stage of curing due to the chain initiation and propagation of the molecules in the curing process.

Dependence of gelation of the sample on the isothermal temperatures.     

Complexation of Surfactant/β‐Cyclodextrin to Inhibit Surfactant Adsorption onto Sand,Kaolin, and Shale for Applications in Enhanced Oil Recovery Processes. Part III: Oil Displacement Evaluation

This proof of concept research evaluates the performance of a surfactant/β‐cyclodextrin (β‐CD) inclusion complex during chemical flooding for enhanced oil recovery. It was hypothesized that the encapsulated surfactant propagates well through the porous media. Sodium dodecyl sulfate (SDS) was used to study the surfactant/β‐CD complexations. Phase behavior analysis was carried out to prepare the most favorable chemical slug formulation. A series of core flooding tests were conducted to determine the efficiency of the SDS/β‐CD inclusion complex in displacing residual oil. Surfactant flooding was conducted as tertiary oil recovery mode (after mature water flooding) by injecting 0.3 pore volume (PV) of the optimum surfactant slug that was chased by 0.3 PV of a polymer slug; followed by continuous water flooding until oil production stopped. The experimental results indicate that the encapsulated surfactant propagates well through the sandpack system and consistently produces higher incremental oil recoveries that range from 40 to 82 % over the incremental oil recovery achieved by conventional surfactant flooding.