A New Method to Solve Film Model for CO_2 Absorption with Aqueous Solution of AT-Methyldiethanolamine

The shooting method and the difference method are used for numerical simulation of CO2 absorption with aqueous solution of methyldiethanolamine (MDEA). It is demonstrated that these methods are available for the steady-state model, which may be expressed as a set of differential algebraic equations (DAEs) with two-point boundary values. This method makes it possible not only to obtain the concentration profiles for MDEA system, but also to reveal the effect of CO2 interfacial concentration on the enhancement factor. With this numerical simulation, the mass transfer process with multicomponent diffusion and reactions can be better understood.     

Numerical study and acceleration of LBM-RANS simulation of turbulent flow

The coupled models of LBM(Lattice Boltzmann Method) and RANS(Reynolds-Averaged Navier–Stokes) are more practical for the transient simulation of mixing processes at large spatial and temporal scales such as crude oil mixing in large-diameter storage tanks. To keep the efficiency of parallel computation of LBM, the RANS model should also be explicitly solved; whereas to keep the numerical stability the implicit method should be better for RANS model. This article explores the numerical stability of explicit methods in 2D cases on one hand, and on the other hand how to accelerate the computation of the coupled model of LBM and an implicitly solved RANS model in 3D cases. To ensure the numerical stability and meanwhile avoid the use of empirical artificial limitations on turbulent quantities in 2D cases, we investigated the impacts of collision models in LBM(LBGK, MRT)and the numerical schemes for convection terms(WENO, TVD) and production terms(FDM, NEQM) in an explicitly solved standard k–ε model. The combination of MRT and TVD or MRT and NEQM can be screened out for the 2D simulation of backward-facing step flow even at Re = 10~7. This scheme combination, however, may still not guarantee the numerical stability in 3D cases and hence much finer grids are required, which is not suitable for the simulation of industrial-scale processes. Then we proposed a new method to accelerate the coupled model of LBM with RANS(implicitly solved). When implemented on multiple GPUs, this new method can achieve 13.5-fold acceleration relative to the original coupled model and 40-fold acceleration compared to the traditional CFD simulation based on Finite Volume(FV) method accelerated by multiple CPUs. This study provides the basis for the transient flow simulation of larger spatial and temporal scales in industrial applications with LBM–RANS methods.     

用新的矩方法研究弯管中纳米颗粒的输运与凝结(英文)

Transport of nanoparticles and coagulation is simulated with the combination of CFD in a circular bend. The Taylor-expansion moment method (TEMOM) is employed to study dynamics of nanoparticles with Brownian motion, based on the flow field from numerical simulation. A fully developed flow pattern in the present simulation is compared with previous numerical results for validating the model and computational code. It is found that for the simulated particulate flow system, the particle mass concentration, number concentration, particle polydispersity, mean particle diameter and geometric standard deviation over cross-section increase with time. The distribution of particle mass concentration at different time is independent of the initial particle size. More particles are concentrated at outer edge of the bend. Coagulation plays more important role at initial stage than that in the subsequent period. The increase of Reynolds number and initial particle size leads to the increase of particle number concentration. The particle polydispersity, mean particle diameter and geometric standard deviation increase with decreasing Reynolds number and initial particle size.     

CO2-乙醇体系中界面对流的混合格子Boltzmann方法三维模拟及实验验证（英文）

By using a hybrid lattice-Boltzmann–finite-difference method (hybrid LBM–FDM method), three-dimensional simulations of solutal interfacial convection were conducted for the process of CO2 absorption into ethanol. A self-renewal interface model is adopted as an interfacial perturbation model. The simulation results revealed some three-dimensional features of the induced interfacial convection, such as the development of diverging cellular flow and Rayleigh plume-like convection in liquid phase. The concentration distribution of the simulation result is validated and found to be in wel agreement with the Schlieren visualization results qualitatively. Addi-tionally, the mass transfer enhancements by interfacial convection were investigated via both simulation and experiment for the absorption process, and the mass transfer is shown to be enhanced by the interfacial convec-tion by about two-fold comparing with that by diffusion.     

甲烷部分氧化制乙炔过程研究

The partial oxidation of hydrocarbons is an important technical route to produce acetylene for chemical industry.The partial oxidation reactor is the key to high acetylene yields.This work is an experimental and numerical study on the use of a methane flame to produce acetylene.A lab scale partial oxidation reactor was used to produce ultra fuel-rich premixed jet flames.The axial temperature and species concentration profiles were measured for different equivalence ratios and preheating temperatures,and these were compared to numerical results from Computational Fluid Dynamics(CFD)simulations that used the Reynolds Averaged Navier-Stokes Probability Density Function(RANS-PDF)approach coupled with detailed chemical mechanisms.The Leeds 1.5,GRI 3.0 and San Diego mechanisms were used to investigate the effect of the detailed chemical mechanisms.The effects of equivalence ratio and preheating temperature on acetylene production were experimentally and numerically studied.The experimental validations indicated that the present numerical simulation provided reliable prediction on the partial oxidation of methane.Using this simulation method the optimal equivalence ratio for acetylene production was determined to be 3.6.Increasing preheating temperature improved acetylene production and shortened greatly the ignition delay time.So the increase of preheating temperature had to be limited to avoid uncontrolled ignition in the mixing chamber and the pyrolysis of methane in the preheater.     

A Reynolds mass flux model for gas separation process simulation:I. Modeling and validation

Separation process undertaken in packed columns often displays anisotropic turbulent mass diffusion. The aniso-tropic turbulent mass diffusion can be characterized rigorously by using the Reynolds mass flux (RMF) model. With the RMF model, the concentration and temperature as well as the velocity distributions can be simulated numerical y. The modeled Reynolds mass flux equation is adopted to close the turbulent mass transfer equation, while the modeled Reynolds heat flux and Reynolds stress equations are used to close the turbulent heat and mo-mentum transfer equations, so that the Boussinesq postulate and the isotropic assumption are abandoned. To val-idate the presented RMF model, simulation is carried out for CO2 absorption into aqueous NaOH solutions in a packed column (0.1 m id, packed with 12.7 mm Berl saddles up to a height of 6.55 m). The simulated results are compared with the experimental data and satisfactory agreement is found both in concentration and temper-ature distributions. The sequel Part II extends the model application to the simulation of an unsteady state ad-sorption process in a packed column.     

Biogas upgrading technologies:Energetic analysis and environmental impact assessment

Biogas upgrading for removing CO2 and other trace components from raw biogas is a necessary step before the biogas to be used as a vehicle fuel or supplied to the natural gas grid. In this work, three technologies for biogas upgrading, i.e., pressured water scrubbing (PWS), monoethanolamine aqueous scrubbing (MAS) and ionic liquid scrubbing (ILS), are studied and assessed in terms of their energy consumption and environmental impacts with the process simulation and green degree method. A non-random-two-liquid and Henry's law property method for a CO2 separation system with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) is established and verified with experimental data. The assessment results indicate that the specific energy consumption of ILS and PWS is almost the same and much less than that of MAS. High purity CO2 product can be obtained by MAS and ILS methods, whereas no pure CO2 is recovered with the PWS. For the environmental aspect, ILS has the highest green degree production value, while MAS and PWS produce serious environmental impacts.     

A study on periodic boundary condition in direct numerical simulation for gas–solid flow

Direct numerical simulation(DNS) of gas–solid flow at high resolution has been carried out by coupling the lattice Boltzmann method(LBM) for gas flow and the discrete element method(DEM) for solid particles. However,the body force periodic boundary condition(FPBC) commonly used to cut down the huge computational cost of such simulation has faced accuracy concerns. In this study, a novel two-region periodic boundary condition(TPBC) is presented to remedy this problem, with the flow driven in the region with body force and freely evolving in the other region. With simulation cases for simple circulating fluidized bed risers, the validity and advantages of TPBC are demonstrated with more reasonable heterogeneity of the particle distribution as compared to the corresponding case with FPBC.     

采用数值模拟方法研究同时氧化烟气中NO和SO2的可行性添加剂

Mechanism analysis on simultaneous oxidation of NO and SO2 with additives was presented and numerical simulation was developed to investigate the performances of three additives on oxidation of NO and SO2. The simulation result showed that reaction temperature, residence time, additive dose and NO concentration influence the oxidation process significantly. There exists an optimum reaction condition for each additive, n-C4H10 has the strongest ability to oxidize NO and SO2.     

CO2 Leakage Identification in Geosequestration Based on Real Time Correlation Analysis Between Atmospheric O2 and CO2

The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux （ALF）, is presented to monitor abnormal CO2 leakage, which can be calculated by atmospheric CO2 and O2 data. The computation shows that all ALF values are close to zero-line without the leakage. With a step change or linear perturbation of concentration to the initial CO2 concen-tration data with no leakage, ALF will deviate from background line. Perturbation tests prove that ALF method is sensitive to linear perturbation but insensitive to step change of concentration. An improved method is proposed based on real time analysis of surplus CO2 concentration in least square regression process, called apparent leakage flux from surplus analysis （ALFs）, which is sensitive to both step perturbation and linear perturbations of concen-tration. ALF is capable of detecting concentration increase when the leakage occurs while ALFs is useful in all pe-riods of leakage. Both ALF and ALFs are potential approaches to monitor CO2 leakage in geosequestration project.     

液相法制备纳米材料的研究进展

介绍了近年来利用液相合成纳米材料的方法,如沉淀法、水热法、溶胶凝胶法、微乳液法、模板法、超临界法、辐射法、离子液体法等,并对其反应原理、特点以及发展状况做了评价。     

恶臭气体危害及其处理技术

文章介绍了恶臭气体的来源和危害,同时全面论述了恶臭气体处理技术,如物理法(掩蔽法、稀释扩散法)、化学法(化学氧化法、光催化氧化法、吸收法、燃烧法)、吸附法、生物法以及低温等离子体净化法。最后,论述了恶臭气体治理技术今后发展的趋势和应用前景。     

聚磷酸铵合成方法的研究进展

系统介绍了聚磷酸铵的生产方法,包括磷酸二氢铵法、磷酸-尿素法、磷酸脲法、磷酸二氢铵-尿素法、磷酸氨化法和磷酸铵-五氧化二磷法。磷酸二氢铵法、磷酸-尿素法、磷酸氨化法得到的产物聚合度较低,低聚合度聚磷酸铵水溶性高,呈中性,适宜作农用肥料;磷酸二氢铵-尿素法和磷酸铵-五氧化二磷法得到的产物聚合度较高,高聚合度聚磷酸铵适宜作阻燃剂。     

二芳基甲酮化合物合成研究进展（待续）

介绍了二芳基甲酮化合物用途、国内外开发过程,叙述了二芳基甲酮化合物制备方法的芳酰氯法、苯甲酸法和三氯甲苯法,并对各种方法的优缺点作了评价。其中芳酰氯法是制备二芳基甲酮化合物最主要的方法,苯甲酸法、三氯甲苯法以及四氯化碳法在制备具特殊结构的二芳基甲酮时显现了比芳酰氯法更好的优势。     

无机粉末发光材料合成的新方法

对９０年代以来无机粉末发光材料合成新方法（溶液—凝胶法,沉淀法,高分子网络凝胶法,水热法,燃烧法,微波法）的特点和研究状况进行了阐述     

汽液相平衡研究进展

概述了近年来汽液相平衡的测定方法:直接法(蒸馏法、静态法、流动法、循环法、泡露点法),间接法(饱和蒸汽压法、沸点仪法)和汽液相平衡计算方法(状态方程法和基团贡献法)的研究现状及其发展趋势,对其进一步的研究做了展望。     

磷灰石中的二氧化硅含量测定的新方法

将动物胶凝聚重量法测定二氧化硅和钼蓝光度法测定二氧化硅的方法相结合,建立了磷灰石中二氧化硅含量测定动物胶凝聚重量法—滤液钼蓝分光光度法的新方法,该方法比原来的重量法、容量法具有更高的精密度和准确度。     

对乙酰氨基酚的合成

本文总结了国内外近年来合成对乙酰氨基酚生产工艺的研究进展,主要介绍了传统二步法、新型二步法、一步法、逐步还原法和生化法,分析了各工艺的优缺点,提出了从环保上和经济上来考虑,新型二步法是对乙酰氨基酚合成的最好方法。     

高纯氟化锂的合成工艺进展

氟化锂是一种重要的无机氟化物,在诸多领域有着广泛的应用。高纯氟化锂的合成可分为直接合成法、离子交换法和溶剂萃取法,直接合成法又分为干法和湿法。详细介绍了各种方法的工艺,与湿法相比较,干法具有工艺简单、投资低、适于连续化生产等优点。采用溶剂萃取法可使氟化锂产品中的过渡金属质量分数降至10^-9级,特别适用于制造光学纤维和锂离子二次电池的电解质。     

2-丙烯酰胺基-2-甲基丙磺酸合成工艺的新进展

2-丙烯酰胺基-2-甲基丙磺酸（AMPS）的合成方法主要有异丁烯法、异丁醇法、羟基磺酸法、异丁烯磺酸法等,对比反应条件,气相异丁烯法是最温和的,适宜工业化生产。目前异丁烯法已成为主流。为提高产品质量,应从反应下手,改进AMPS的生产工艺。主要改进方法有：合成重结晶一步法、添加试剂法、连续法等。合成重结晶一步法将缩短生产周期,提高生产效率;添加试剂将改善反应性能,提高反应质量;连续法生产AMPS投资少,产品稳定,将成为合成AMPS的趋势。