MATLAB(SIMULINK)在造纸浆水平衡计算中的仿真应用

造纸浆水平衡计算是既重要又比较复杂的过程。计算时容易出错,如果不及时检查修正,会影响整个过程。作者利用MATLAB提供的动态系统仿真工具SIMULINK对浆水平衡进行仿真,大大减轻了计算复杂度,并可方便的进行检验,同时可更改工艺流程,具有较强的通用性、灵活性和方便的扩充性。     

亚临界气体喷射器的设计计算

计算气体压缩喷射器可达到喷射系数的研究已很成熟,但对亚临界气体喷射器可达到喷射系数,大多采用气体喷射压缩器的方法进行计算。针对亚临界气体喷射器的特性,给出了3种计算方法:气体喷射压缩器计算方法;喷射泵计算方法;气体喷射器计算方法。研究表明:对膨胀比和压缩比都小于临界压力比的亚临界气体喷射器,膨胀比较大时,工作介质的弹性影响不能忽略;压缩比较小时,引射介质的弹性影响应该忽略;进而得出在膨胀比和压缩比都接近临界压力比时,适宜采用把工作介质视为弹性,引射介质视为非弹性的气体喷射器计算方法;而在膨胀比和压缩比都非常小且接近于1时,应该采用把工作介质和引射介质都视为非弹性的喷射泵计算方法。     

玻璃熔窑碹结构中心角计算公式的研究与开发

列举了国内外相关行业设计手册中有关圆弧碹（圆弧拱、弓形）的计算公式,认为这些设计手册中的中心角计算都比较繁琐、而且间接。为此提出了中心角计算的新型公式,既简捷、又直接,同时还可以扩展到其它参数的计算公式中。     

CALCULATION METHODS FOR DISTILLATION SYSTEMS WITH REACTION

A calculation procedure is presented for the solution of the equations describing a distillation process in which reaction is taking place. A mathematical model based on matrix notation is used to formulate the system equations. It is assumed that the distillation process can be represented by a system of interconnected stages, each of which is well mixed with the vapor and liquid phases in equilibrium. Reaction may take place in the vapor phase, liquid phase, or both. The equations describing this system are first presented. Then a calculation sequence and a correction algorithm are derived for the case in which the liquid and vapor solutions are ideal—that is, the equilibrium ratios are functions only of temperature and pressure and not of composition. The calculation sequence uses as variables of iteration the vectors of vapor flow rate, temperature, and reaction extents. A derivative correction method is used, and equations for the calculation of the Jacobian matrix are derived. The application of the method is illustrated by solution of two sample problems. The special case in which the heat of reaction is small, and constant molal overflow can be assumed, and the case in which the reaction rate is very fast and chemical equilibrium exists in each stage are considered.     

CALCULATION METHODS FOR DISTILLATION SYSTEMS WITH REACTION

A calculation procedure is presented for the solution of the equations describing a distillation process in which reaction is taking place. A mathematical model based on matrix notation is used to formulate the system equations. It is assumed that the distillation process can be represented by a system of interconnected stages, each of which is well mixed with the vapor and liquid phases in equilibrium. Reaction may take place in the vapor phase, liquid phase, or both. The equations describing this system are first presented. Then a calculation sequence and a correction algorithm are derived for the case in which the liquid and vapor solutions are ideal—that is, the equilibrium ratios are functions only of temperature and pressure and not of composition. The calculation sequence uses as variables of iteration the vectors of vapor flow rate, temperature, and reaction extents. A derivative correction method is used, and equations for the calculation of the Jacobian matrix are derived. The application of the method is illustrated by solution of two sample problems. The special case in which the heat of reaction is small, and constant molal overflow can be assumed, and the case in which the reaction rate is very fast and chemical equilibrium exists in each stage are considered.     

压力容器强度计算中如何考虑腐蚀裕量

本文就国内外标准在压力容器强度计算中如何考虑腐蚀裕量进行对比分析,认为我国标准中强度计算公式的内径取值在有腐蚀的情况下应附加两倍腐蚀裕量较为合理。     

A simplified method for correction of polydispersities from gel permeation chromatography

A simple method is presented for correction of polydispersity obtained by gel permeation chromatography. The method proposed utilizes well-characterized polystyrene standards for both instrument calibration and construction of a correction curve which is then used for calculation of weight-average and number-average molecular weights and polydispersity of samples to be characterized.     

离心泵组合操作方式的简易判据

多台离心泵的串联和并联操作均能提高管路的流量,但对不同的管路系统哪种操作方式更能有效地提高流量,必须通过计算才能确定。因此提出一种离心泵组合操作方式的简易判据,能方便、准确、快速地确定适宜的离心泵组合操作方式。     

伞顶固定顶盖的设计

大型贮槽固定式罐顶的一种形式——伞顶的构造与构件的计算。伞顶是介于锥顶与拱顶之间一种固定式罐顶结构形式。它同时具有锥顶和拱顶的优点,值得在生产中应用。     

PTA氧化过程在线工艺计算技术开发与应用

介绍PTA氧化过程在线工艺计算技术开发与现场实施的重点和难点,利用基于氧化反应机理的过程模型,结合现场实施的在线模型参数校正及化验数据偏差校正的双重校正技术,开发在线工艺计算软件包,并在工业现场PTA氧化过程在线计算上得到成功应用。     

大型立式圆筒形储罐拱架应力强度计算

介绍目前大型立式圆筒形储罐的罐顶主要结构,比较其优缺点,采用三铰拱原理对拱架梁结构建立力学模型,推导出详细的计算公式,并将推导结果用于储罐的设计计算。通过比较,该计算方法符合工程实际,能可靠地用于大型储罐的拱架应力强度计算,为拱架强度计算提供理论依据。     

吸收塔填料层高度的解析计算

对相平衡线为曲线的低浓度吸收操作系统，提出分段计算和曲线拟合—数值积分两种解析算法。这两种方法可得到满意的计算精度，同时可用计算机进行计算，方便易行     

Vermischungseffekte in Flüssig/Flüssig-Extraktionskolonnen

Axial mixing in liquid/liquid countercurrent extractors . Methods are considered for the determination of longitudinal mixing in many countercurrent extractors. It is found that only the single phase mixing of the continuous phase can be accurately determined; with certain reservations this also applies to the disperse phase. In the case of RDC and ARD in particular, correlations are available which permit calculation of Bodenstein numbers for both phases. Such scale-up calculations are not recommended for many extractors. It is very important to establish adequate correlations for calculation of mixing of the disperse phase in order to obtain exact dispersion heights in connection with those of the continuous phase.     

Die Abscheidung von Partikeln aus Gasen in Faserfiltern

Particle collection by fibrous filters . Technically employed fibre filters can be classified according to their construction and application in two major groups: deep bed filters and fabric filters. Approaches to the calculation of the collection efficiency for both types of filters start from a clean nondusted filter layer. From this one examines only the initial state, which is especially critical, while the degree of collection as a rule becomes better with increasing dust accumulation. Various models are available for the calculation of the pressure drop. The initial pressure drop for deep bed filters can be calculated with the help of the resistance model. Especially important are those estimates, which for purification filters describe the pressure drop or the gas flow with increasing dust accumulation, because these equations can serve directly for the dimensioning of filter plants. Of courese, characteristic permeability values for filter fabric and dust layer must be determined beforehand. The possibilities and problems of these calculations, as well as open questions, will be discussed.     

气体燃爆泄放过程中燃烧速率的评价

在设备上安装超压泄压装置是为防止设备内部因爆炸而发生破坏所广泛采用的方法,其设计关键是合理、有效的泄放面积。用数值计算方法模拟可燃气体燃爆泄放过程,从而对泄放面积进行数值求解是燃爆泄放研究的主要方向之一。在数值计算中一个相当重要的参数就是燃烧速度,它用以表征气体的化学特性。目前,有关燃烧速度的计算存在几种不同的关联式,其精度将影响数值计算的准确性和可靠性。     

A superstructure-based framework for simultaneous process synthesis,heat integration,and utility plant design

We propose a superstructure optimization framework for process synthesis with simultaneous heat integration and utility plant design. Processing units in the chemical plant can be modeled using rigorous unit models or surrogate models generated from experimental results or off-line calculations. The utility plant subsystem includes multiple steam types with variable temperature and pressure. For the heat integration subsystem, we consider variable heat loads of process streams as well as variable intervals for the utilities. To enhance the solution of the resulting mixed-integer nonlinear programming models, we develop (1) new methods for the calculation of steam properties, (2) algorithms for variable bound calculation, and (3) systematic methods for the generation of redundant constraints. The applicability of our framework is illustrated through a biofuel case study which includes a novel non-enzymatic hydrolysis technology and new separation technologies, both of which are modeled based on experimental results.     

应用Excel进行泡点与露点计算

泡点与露点计算是化工热力学课程中气液平衡计算的重要内容,也是教学中的难点。目前,教科书中只讲了计算方法,缺少实际计算的展示。本文介绍了微软电子表格Excel在泡点与露点计算中的应用。将已知量、待求量初值与计算公式输入电子表格的各单元格中,求出各组分的气相逸度与液相逸度,根据气液平衡准则,采用Excel多变量规划求解的强大计算功能,即可计算出混合物的泡点压力、泡点温度、露点压力与露点温度。计算过程简单明了,无需编程,方便教学演示,是一种值得推广的教学与实用计算方法。     

Computation of plate columns for NOx absorption by a new stage-to-stage method

A new stage-to-stage method has been developed for the calculation of NX_x absorption columns. Each stage of the absorption column is simulated as a combination of a bubble column reactor (absorption) and an adiabatic plug for reactor (oxidation). The bubble column reactor is modelled as two single stirred tank reactors, one as a gas-phase and one as a liquid-phase reactor, both coupled by mass and heat transfer. In this hydrodynamic model, a dynamic approach is adopted, in which the gas-phase transport of N₂O₄ is the limiting step for the absorption. A gas-phasepseudo-enhancement for factor for N₂O₄ is therefore introduced. The balance equations for a single phase of the bubble column are solved with a Newton-Raphson algorithm. The entire column calculation is divided into a gas and a liquid side. On both sides, the stage-to-stage method is applied in such way that the overall calculation is performed as a loop process. The direction of the loop calculation follows that of the flow: gas-side upwards and liquid-side downwards.     

微量甲醛标准溶液的配制与标定分析──以碘量法为例

测定样液中微量甲醛的含量时,需事先配制和标定含微量甲醛的标准溶液.碘量法是标定甲醛溶液的常用方法.为获得具有较好精确度的微量甲醛标准溶液,根据滴定分析原理进行计算后认为,配制质量浓度为1000 mg/L的标准甲醛储备液既适宜标定,也便于稀释应用.在标定中所用的硫代硫酸钠溶液和碘液配制成合适的浓度有利于提高标定甲醛储备液...     

Absorption with simultaneous complex reactions in both phases, demonstrated by the modeling and calculation of a counter-current flow column for the production of nitric acid

Separation processes with simultaneous chemical reactions play an important part in large-scale production. The calculation of the proper devices, usually plate columns, has not been satisfactorily solved in a general form. We present here an adequate model and a numerical method of calculation, with a corresponding computer program which allows the calculation of plate columns for absorption occurring with simultaneous reaction in both phases. The number of the reactant species and the number of the corresponding reactions is not limited. A column has been calculated rigorously for the most important industrial example of this kind of reaction, the absorption of nitrous gases in the production of nitric acid.