对氨吸收制冷装置有关问题的初步探讨

氨吸收制冷装置随着小石油化工的发展而不断前进。近年来,它作为节能措施更引起人们的重视. 本文从常州石油化工厂(下称常石化)130万大卡/时制冷装置为例对有关问题进行了初步探讨(工作原理见图一). 一、小石化氨吸收制冷流程浅谈氨吸收制冷流程一般可分单级氨吸收制冷和双级氨吸收两种,对于向小石化裂解气分离提供冷量来说,根据资料报道及有关厂的实践证明,单级发生氨吸收制冷如使放气范围在6％     

氨吸收制冷工艺中的节能系统

笔者在本文中从氨吸收制冷工艺基本原理出发,阐明了氨吸收制冷工艺的操作流程。介绍了氨吸收制冷工艺的节能特点,分析了氨吸收制冷工艺中节能系统的技术特性。除此之外,简要说明了氨吸收制冷工艺节能系统的应用现状,并展望了未来的氨吸收制冷工艺节能系统。     

基于Aspen Plus的氨吸收制冷流程模拟

通过对氨吸收制冷工艺的深入研究,运用Aspen Plus软件模拟氨吸收制冷流程,并研究分析吸收器操作压力对出口氨水浓度和液氨蒸发温度的影响。     

冷冻站装置溶液冷却器内漏原因及解决措施

1工艺流程简述云南解化清洁能源有限公司解化化工分公司二甲醚厂冷冻站装置采用吸收制冷和压缩制冷相结合的混合制冷流程,其作用是为低温甲醇洗装置提供冷量。其流程为:由低温甲醇洗氨蒸发器来的气氨经氨压机压缩冷却后,进入吸收器C17401A/B/C被稀氨水吸收,吸收过程产生的热量由循环冷却水带走;浓氨水由氨水泵送往溶液热交换器C17403A/B,被高温稀氨水加热到     

合成氨装置中制冷方式的选择与优化

分析了合成氨装置中制冷工艺的原理、流程和特点;比较了氨吸收制冷和压缩制冷方式的技术经济指标;提出了降低制冷装置能耗的工艺优化方案和设计改进措施。     

合成氨厂制冷方式的选择

介绍了氨吸收制冷工艺和压缩制冷工艺,并对两种工艺进行了比较。氨吸收制冷可以回收余热,节省电能;氨压缩制冷设备投资低。     

CO_2-NH_3复叠与NH_3制冷系统的流程参数比较

设计了典型的CO2-NH3复叠式制冷流程和NH3两级压缩制冷流程,对流程进行了模拟计算,比较了两者的关键参数,并分析了换热器的热流分布及氨系统的参数优化。结果表明:在蒸发温度-45℃的条件下,复叠式系统的压缩机总功耗、制冷剂NH3流量小于氨系统,但氨系统具有较大规模的中温制冷量,其总制冷系数COP大于复叠式系统。复叠式系统冷凝蒸发器的两相流间换热温差较小,而氨系统中间冷却器的换热温差较大。随着低压级排气压力的上升,以及中间温度的降低,氨两级压缩机的总功耗呈下降趋势。     

氨吸收制冷与氨压缩制冷的技术经济比较

<正> 低位能热的利用是一个值得研究的课题,而化工厂和炼油厂内则有大量的低位能热。通常,这些低位能的热量给冷却水带走或散失于大气中,十分可惜。如何充分利用低位能热,节约单位产品的能牦,为低位能热开辟新的利用途径是个十分迫切的问题。本文想结合炼油厂的气体分离来比较一下氨吸收制冷与氨压缩制冷的技术经济问题。目前,国内外在石油气分离装置中所选用的制冷方法,有氨压缩制冷、氨吸收制冷、蒸汽喷射制冷等几种类型,其中应用较广的是氨压缩制冷和氨吸收制冷。氨     

氨吸收制冷工艺在我厂的应用

我厂合成氨制冷工艺一直采用传统的氨压缩制冷。１９９８年，在煤制氨总体技术改造中首次采用国内设计的氨吸收制冷工艺，为低温甲醇洗提供冷量。该装置投运已近一年的时间，工艺操作稳定，与氨压缩制冷工艺对比，该工艺具有一定的优越性和实用性。１　工艺流程该系统工艺流程见图１。氨吸收制冷工艺流程主要由吸收、精馏、冷图１　氨吸收制冷工艺流程图１－吸收器；２－浓溶液贮槽；３－氨水泵；４－溶液热交换器；５－发生器；６－精馏塔；７－冷凝器；８－液氨贮槽；９－回流泵；１０－排出氨换热器；１１－过冷器；１２－氨冷器；１３－…     

氨吸收制冷工艺与压缩制冷工艺的比较

介绍了氨吸收制冷工艺和压缩制冷工艺,并进行了两种工艺的比较,大型煤气化和液化生产企业中采用氨吸收制冷工艺,既回收了余热,又节省了电能,具有很好的经济效益。     

THE ADAPTIVE AUTOREGRESSIVE MODELS FOR THE SYSTEM DYNAMICS AND PREDICTION OF BLAST FURNACE

The blast furnace can be viewed as a time-varying stochastic system. The Adaptive Autoregressive (AAR) models are proposed to characterize such systems. AAR identification is a method of successive parameter estimation by using recursive formulas with variable forgetting factors to closely track time-varying parameters. A simple example is presented to illustrate the parameter tracking capability of the AAR models. Based on the prediction errors, the AAR models of blast furnace are compared with the conventional time series models. Through this comparison, the AAR models prove to be superior to the other time series models, since the latter are suitable only for time-invariant systems. It is concluded that during smooth operation, just the AAR scalar model is required for forecasting as operational guide. When the operation is uneven, the AAR vector model provides the better results. To control the performance of this process the data should be sampled under uneven operating condition, where the AAR vector model is the best among all the models considered and can properly express the dynamic relationship between the input and output variables.     

Thermodynamic Modeling of the MgO–Al2O3–CrO–Cr2O3 System

A complete critical evaluation and thermodynamic modeling of the phase diagrams and thermodynamic properties of the MgO–Al₂O₃–CrO–Cr₂O₃ system at 1 bar total pressure are presented. Optimized equations for the thermodynamic properties of all phases are obtained which reproduce all available thermodynamic and phase equilibrium data within experimental error limits from 25°C to above the liquidus temperatures at all compositions and oxygen partial pressures. The optimized thermodynamic properties and phase diagrams are believed to be the best estimates presently available. The database of the model parameters can be used along with software for Gibbs energy minimization in order to calculate any type of phase diagram section.     

Thermodynamic Modeling of the FeO–Fe2O3–MgO–SiO2 System

The liquid and solid phases in the FeO–Fe₂O₃–MgO–SiO₂ system are of importance in ceramics, metallurgy, and petrology. A complete critical evaluation and thermodynamic modeling of the phase diagrams and thermodynamic properties of this system are presented. Optimized equations for the thermodynamic properties of all phases are obtained that reproduce all available thermodynamic and phase equilibrium data within experimental error limits from 25°C to above the liquidus temperatures at all compositions and oxygen partial pressures. The optimized thermodynamic properties and phase diagrams are believed to be the best estimates presently available. The database of the model parameters can be used with software for Gibbs energy minimization to calculate any type of phase diagram section.     

Critical Evaluation and Thermodynamic Modeling of the MgO–MnO–Mn2O3–SiO2 System

A complete literature review, critical evaluation, and thermodynamic optimization of phase diagrams and thermodynamic properties of the MgO–MnO–Mn₂O₃–SiO₂ system at 1 atm pressure are presented. The molten oxide phase was described by the Modified Quasichemical Model considering the short‐range ordering in molten oxide, and the Gibbs energies of solid solutions were described using the Compound Energy Formalism considering the crystal structure of each solid solution. A set of optimized model parameters of all phases was obtained which reproduces all available and reliable thermodynamic data and phase diagrams within experimental error limits from 25°C to above the liquidus temperatures over the entire range of composition under the oxygen partial pressures from metallic saturation to 1 atm. The database of the model parameters can be used along with software for the Gibbs energy minimization to calculate any phase diagram section and thermodynamic property within the present system.     

Macroscopic model of concrete subjected to alkali-aggregate reaction

The structural behaviour of concrete affected by alkali-aggregate reaction (AAR) is difficult to model due to the amount of random parameters that govern this chemical process. The aim of this work is to present a macroscopic approach whose main features are the consideration of uncoupling between AAR and stress and the representation of the anisotropic characteristic of chemical swelling. Experimental results concerning reactive concrete samples were simulated to verify whether the model was capable of describing the behaviour of affected structures under certain loading and boundary conditions. Loading-unloading response was also considered to simulate the effect of joints opening, which is a commonly used technique for releasing AAR generated stresses in affected structural elements. The obtained results were compared to test data and showed good agreement.     

DME-CO2-CH3OH和DME-CO2-C2H5OH体系的高压汽液相平衡研究

In this study, the Gibbs-Duhem equation was applied to make the thermodynamic consistency test and thermodynamic model estimation for systems of CO2-DME （dimethyl ether）, DME-CH3OH, CO2-CH3OH and DME-C2H5OH systems on the basis of the vapor-liquid equilibrium （VLE） experimental data in published reports. And the NRTL binary interaction parameters of the systems mentioned above were regressed by the VLE data and were subjected to a thermodynamic consistency test because the study showed that PR-NRTL model combination was appropriate for the four systems mentioned above. The regressed binary interaction parameters were used to estimate the VLE for DME-CO2-CH3OH at temperatures of 313.15K and 333.15K, and the estimated result was coincident with the experimental data. On the basis of the predicted VLE data for systems of DME-CO2-CH3OH and DME-CO2-C2H5OH, the VLE behaviors of the two systems were studied by the phase diagrams of these two ternary systems, with the forms of both the two dimensional and three dimensional phase diagrams, respectively.     

热力学研究在锂离子电池回收中的应用

废旧锂离子电池的回收是近年来资源回收研究领域的热点,但相关回收体系的理论基础研究仍然较为薄弱。其中在热力学研究方面,研究者们大多仍以经典冶金物理化学理论为指导,并借助E-pH图、优势区域图等方法开展研究。本文对该领域已有的较为典型的热力学研究进行综述,详细阐述了热力学研究对废旧锂离子电池常规回收工艺的指导作用以及对三元正极废料选择性提锂、磷酸铁锂正极废料选择性提锂和失效电池材料再生修复等新技术开发的启发性作用。同时,基于对现有锂离子电池回收体系热力学研究的总结和评述,指出了未来锂离子电池回收体系热力学研究亟待解决的关键问题和发展方向。     

预防碱—集料反应的专家系统

混凝土碱－集料反应及其防治已成为全世界共，研究和重视的问题。“预防混凝土碱－集料反应的专家系统”是针对我国现状而研制的用于解决我国ＡＡＲ预防问题的计算机智能系统。它以唐明述教授几十年来积累和收集的ＡＡＲ预防知识为主，同时吸收和补充了国内外其他ＡＡＲ专家的知识和经验。知识收集经历了“整体－具体－一般”的过程；知识整理采因素层次化分析法，并设计：可装卸式框架结构”来表示知识。ＰＡＡＲＣＥ采用模块化...     

Computation of Ternary Molten Salt Phase Diagrams

The thermodynamic properties of all phases in the 15 binary systems formed among the salts LiCl, NaCl, KCI, MgCl₂, CaCl₂, and SrCl₂, were obtained and expressed in mathematical form by a critical analysis of the measured binary phase diagrams and of published binary thermodynamic data. Interpolation procedures were then used to estimate the thermodynamic properties of the 20 ternary systems formed among the 6 salts and all 20 ternary phase diagrams were calculated using a computer program designed for the purpose. Agreement with the measured phase diagrams for the 8 ternary systems for which measured diagrams are available is good.