基于状态观测器的电镀液温度状态反馈控制系统

针对电镀液温度控制系统,引入状态反馈控制.相对于传统的反馈控制,本方法可以获得更优异的性能.另外,考虑到镀液温度控制具有纯迟延的特点,提出了一种消去纯迟延的方法.仿真验证结果显示,控制效果良好.     

Hybrid extended Luenberger-asymptotic observer for bioprocess state estimation

State observers generate estimates of non-measured variables based on a mathematical model of the process and some available hardware sensor signals. On the one hand, exponential observers, such as Luenberger observers or Kalman filters, have an adjustable rate of convergence, but strongly rely on the accuracy of the process model. On the other hand, asymptotic observers use a state transformation in order to avoid using the (usually uncertain) kinetic model, but have a rate of convergence imposed by the process dilution rate. In an attempt to combine the advantages of both techniques, a hybrid observer is developed, which evaluates a level of confidence in the process model and, accordingly, evolves between the two above-mentioned limit cases (exponential or asymptotic observer). In particular, attention is focused on a hybrid “Luenberger-asymptotic” observer, for which a rigorous stability/convergence analysis is provided. The efficiency and usefulness of the proposed observer is demonstrated with a bioprocess application example.     

State observer scheme for joint kinetic parameter and state estimation

The development and acceptance of model-based monitoring tools in the bioprocess industry is made difficult by the usually large uncertainty associated with the process model. A natural approach to handle this issue is the design of adaptive state observers for the joint estimation of the process state and some of the uncertain model parameters. However, the state extension is often restricted to a few parameters only, for which observability conditions are satisfied with the available measurement information. In this study, this latter issue is circumvented by the combination of two observers: (a) a receding-horizon observer is designed for the joint estimation of the state and uncertain model parameters, and (b) an asymptotic observer, which provides state estimates independently of the kinetic model, is used to provide the missing additional information to the receding-observer, thus avoiding observability loss. This paper derives the properties of this combined state estimation scheme and demonstrates its performance with a realistic simulation case study of animal cell cultures.     

Calculation of the temperature of a condensed medium behind a shock front

Novosibirsk. Translated from Fizika Goreniya i Vzryva, Vol. 24, No. 1, pp. 75–79, January–February, 1988.     

Measuring the brightness temperature of a detonation front in a porous explosive

The detonation temperature of pressed PETN grains with a relative volumetric concentration of air pores of 0.0047–0.147 was measured using an optical fiber pyrometer at wavelengths of 678 and 487 nm. The nonequilibrium nature of the radiation of the detonation front was shown to be due to the presence of two radiation sources with different temperatures. One source was the explosion products and the other was the strongly compressed air pores, in which air was heated to a temperature above 10⁴ K. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 108–110, July–August, 2007.     

Degrees of freedom analysis for a distillation column

Precise determination of the number of degrees of freedom is of great significance in the design, operation, renovation, and optimization of chemical plants. Two fundamental works devoted to the determination of the number of degrees of freedom for chemical technology processes are considered, and the basic distinctions between the two approaches are discussed. It is explained why the numbers of degrees of freedom determined for the similar chemical engineering objects considered in those works are different.     

Transient state techniques for mass transfer characterization of a gas-liquid packed column

We designed and built a flexible gas-liquid pilot plant to evaluate the performances of different packings. Dynamic methods involving transferable and non-transferable tracers were used to achieve this goal. A model taking into account axial dispersions in both phases represented the packing mass transfer performances. Mass transfer coefficient, liquid and gas phases axial dispersions and holdup were estimated by performing a time domain fitting of the model response to experimental data. This method has been applied successfully to a commercially available packing (polypropylene Ralu flow 25 from Raschig).     

Stability analysis of a bubble column

The aim of the paper is to study the transition between homogeneous and heterogeneous flows in bubble columns, by taking into account the destabilizing effects of both added mass force and deformation of the bubbles. The transition is expressed in terms of instability of a uniform bubbly flow. Special attention is paid to closure relations involving pressure terms at the gas–liquid interface. The models presented in this paper give instructive information on the transition between homogeneous and heterogeneous flows in bubble columns, highlighting the respective weight of physical phenomena, modeled in terms of closure relations introduced in the two-fluid model.     

Decentralized temperature control of a pilot dividing wall column

The technology of dividing wall columns offers to save high amounts of operating and investment cost compared to conventional distillation columns and their configurations. The practical application is still limited due to a lack of experience and high interactions among the process variables.The present work deals with the development and test of a control system for a pilot dividing wall column. Within this, decentralized temperature control systems are designed by a systematic approach. Furthermore, these systems are evaluated concerning the process stability, the providing of defined product purities and the respective requirement of energy in case of disturbances. The focus is on simulative and experimental investigations in order to assure the practicability of the developments. The presented results show the effectiveness of the applied methods.     

Modelling and optimization of the steady state operation of a vapour recompression distillation column

A data processing system adapted to a vapour recompression distillation unit is described. It is shown that it allows the identification of mass transfer parameters of the distillation column, of heat exchange of the boiler-condenser, of manometric and flow coefficients of compressor and of its isentropic yield. This last parameter and the overall output of the unit pass through a maximum for the same value of the compressor rotation speed.     

分壁精馏塔分离芳烃的稳态及动态研究

采用分壁精馏塔（DWC）严格稳态模型,对比苯、甲苯、二甲苯以及均三甲苯四组分混合物的常规分离和分壁精馏塔分离方法,稳态分析结果表明：直接序列分壁精馏塔流程较常规三塔分离序列可减小再沸器负荷18.9%,年度总成本TAC可降低13.0%,DWC有效避免了常规塔器分离过程中中间组分的返混现象。在Aspen Dynamic环境下对最优序列进行组分控制,结果表明组分控制可很好地应对进料流量和组分组成波动。     

Steady state hydrodynamics and mass transfer characteristics of a karr extraction column

The steady state hydrodynamics of the holdup in a 15 cm column agree quite well with mechanistic predictions at conditions approaching flooding. In the presence of mass transfer (acetic acid from the dispersed kerosene phase to the continuous water phase), the holdup data below flooding are not well predicted by the model due to enhanced droplet coalescence. The prediction of holdup at flooding is a function of the ratio of the flow rates but is independent of the physicochemical properties of the extraction system, and therefore can be used to estimate the flooding holdup regardless of the occurrence of mass transfer. In the second part of the paper, steady state mass transfer characteristics of the column were also simulated using a mechanistic model. Despite the difficulty of estimating parameters such as the mass transfer coefficient, the model curves could be arbitrarily adjusted to fit observed exit concentrations. These steady state results provide useful insights on the non-linearity of the system from a control viewpoint.     

基于广义状态观测器的催化裂化装置软仪表

与常规的输出校正软仪表不同,催化裂化装置软仪表的主导变量完全不可测,只能通过辅助变量进行在线校正,因此利用状态观测器构造催化裂化装置软仪表。催化裂化装置为指数1型广义非线性系统,理论分析证明,如果指数1型广义非线性系统在工作点线性化得到的广义线性变参数系统能检测,则可以通过线性化系统的在线极点配置来选取合适的状态观测器反馈增益阵,以确保广义状态观测器存在并在较大范围内是稳定的,从而保证软仪表对主导变量的在线估计值可以收敛于理论值。仿真结果表明,即使催化剂循环量为不可测输入变量,将其扩展为状态变量后,利用提升管反应器出口温度作为辅助变量进行在线校正,即可构成催化裂化装置软仪表完成对油品产率、催化剂循环量等不可测变量的在线估计,估计值能够稳定收敛到理论值并具有较好的动态性能。     

轮胎温度场有限元分析系统的设计与开发

研究轮胎滚动过程中的稳态热平衡状态。通过经验数据积累，从轮胎结构参数设计、断面网格划分和有限元分析、热物性参数数据库建立和温度场计算、试验数据拟合及结果输出五方面，设计轮胎温度场有限元分析系统。通过与试验数据对比，证明输出的温度场云图与稳态轮胎温度场温度分布情况一致。     

The effect of temperature on the growth of ultradispersed diamonds at a detonation front

Experimental data verify that particles of ultradispersed diamond produced during the detonative decomposition of an explosive material can grow in the solid crystalline state. A method is proposed, and increasing the size of particles of ultradispersed diamond by raising the temperature at the detonation front is shown to be feasible.Biisk. Scientific and Technical Council, Almai. Translated from Fizika Goreniya i Vzryva, No. 1, pp. 109–112, January–February, 1995.     

Design of a packed column for ethanol extraction. Equilibrium and kinetics studies

Computer-aided design of a packed column to remove ethanol from aqueous solution with dibutyl butylphosphonate (DBBP) was accomplished with a programme based on the Pratt method and on the slip velocity equation. Reliable data for successful computation were obtained from literature correlations (drop size, hold-up and axial mixing coefficients for different types of packing) and from experimental work (equilibria and kinetics). Equilibrium studies on the H₂O-ethanol-dibutyl butylphosphonate system were performed at different temperatures. A decrease in temperature increased the selectivity of the extractant while the distribution coefficient of ethanol, K_D ≈ 1.0, remained constant. The behaviour of the system kinetics towards temperature is assessed in order to determine the initial mass transfer flux (892 × 10^?3 kg m^?2s^?1, 30°C) and the activation energy, 22.9 kJ/kmol. The process is governed by the diffusion of the species involved. The influence of the type of packing of the column on its design is analyzed from the inventory volume of the solvent, the total volume of the column and the axial dispersion coefficients under normalised inlet and outlet conditions.