Energy saving in batch distillation for separation of ternary zeotropic mixture integrated with vapor recompression scheme: dynamics and control

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Gandu Radhika ◽  
Akash Kumar Burolia ◽  
Pandiyan Kuppusamy Raghu Raja ◽  
Seshagiri Rao Ambati ◽  
Dipesh S. Patle ◽  
...  
Keyword(s):  
Closed Loop ◽  
Energy Savings ◽  
Open Loop ◽  
Single Stage ◽  
Large Temperature ◽  
Thermodynamic Efficiency ◽  
Batch Distillation ◽  
Proportional Integral ◽  
Zeotropic Mixture ◽  
Vapor Recompression

Abstract In this work, tight composition control and in parallel the operation is integrated with vapor recompression scheme (VRC) is proposed to achieve energy savings and maximum product at a specified high purity for the separation of ternary zeotropic mixture in batch distillation. Firstly, the model representing a ternary system of hexanol/octanol/decanol has been simulated to analyze the open-loop and close-loop dynamics of the process. Secondly, the open-loop and closed-loop operations are integrated with single stage VRC scheme to achieve energy savings. Single stage VRC is operated at very high compression ratio (CR) due to the large temperature difference of the top and bottom streams in batch distillation column. To further improve the thermodynamic efficiency of single stage VRC, double stage compression without intercoolers between the stages of VRC is proposed. Two control schemes have been implemented for constant composition, namely proportional integral (PI) controller and nonlinear gain scheduling proportional integral (GSPI) with and without VRC in closed-loop. The results shows that double stage VRC with GSPI algorithm provides better performance than conventional in terms of energy, product amount and Integral Square Error (ISE).

scholarly journals Control-Oriented High-Frequency Turbomachinery Modeling: Single-Stage Compression System 1D Model

1993 ◽  
Author(s):  
O. O. Badmus ◽  
S. Chowdhury ◽  
K. M. Eveker ◽  
C. N. Nett
Keyword(s):  
Experimental Data ◽  
High Frequency ◽  
Closed Loop ◽  
Open Loop ◽  
Rotating Stall ◽  
Single Stage ◽  
Model Parameters ◽  
Compression System ◽  
First Order ◽  
Direct Model

In this paper, a 1D unsteady compressible viscous flow model of a generic compression system previously developed by the authors is applied to a multi-stage axial compressor experimental rig configured for single–stage operation. The required model parameters and maps are identified from experimental data. The resulting model is an explicit system of 9 first order ODE’s. The model inputs are compressor speed, nozzle area, compressor discharge bleed area, plenum bleed area, inlet total pressure and entropy, and nozzle and bleed exit static pressures. The model and experimental data are compared with respect to both open–loop uncontrolled and closed–loop controlled behaviors. These comparisons focus on i) forced transients and ii) global nonlinear dynamics and bifurcations. In all cases the comparison between the model and experimental data is excellent. Of particular interest is the ability of the model, which does not include any hysteretic maps, to predict experimentally observed hysteresis with respect to the onset and cessation of surge. This predictive capability of the model manifests itself as the coexistence of a stable equilibrium (rotating stall) and a stable periodic solution (surge) in the model at a single fixed set of system input values. Also of interest is the fact that the controllers used for closed–loop comparisons were designed directly from the model with no a posteriori tuning of controller parameters. Thus, the excellent closed–loop comparisons between the model and experimental data provide strong evidence in support of the validity of the model for use in direct model based controller design. The excellent agreement between the model and experimental data summarized above is attributed in large part to the use of effective lengths within the model, as functions of axial Mach number and nondimensional compressor rotational speed, as prescribed by the modeling technique. The use of these effective lengths proved to be far superior to the use of physical lengths. The use of these effective lengths also provided substantial improvement over the use of physical lengths coupled with fixed first order empirical lags, as proposed by other authors for the modeling of observed compressor dynamic lag. The overall success of this model is believed to represent a positive first step toward a complete experimental validation of the approach to control–oriented high–frequency turbomachinery modeling being developed by the authors.

Comparative Control Study of a High-Purity Ternary Batch Distillation

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
P. V. Radha Krishna Adari ◽  
Amiya K Jana
Keyword(s):  
High Purity ◽  
Distillation Column ◽  
Open Loop ◽  
Batch Distillation ◽  
Performance Study ◽  
Proportional Integral ◽  
Start Up ◽  
Control Schemes ◽  
Loop Dynamics ◽  
Gain Scheduled

This paper presents a comparative closed-loop performance study on a multicomponent batch distillation column that produces high-purity distillate product. Initially, the distillation model representing a ternary system of cyclohexane-toluene-chlorobenzene has been simulated to observe the open-loop dynamics at the start-up as well as production phase. The next three control schemes, namely classical proportional integral (PI) controller, nonlinear proportional integral (NLPI) control strategy and gain-scheduled proportional integral (GSPI) law, have been designed and applied on the simulated distillation column. Numerical experiments based on servo and regulatory tests show that the GSPI algorithm provides relatively better results than the other two PIs.

MODELING AND ANALYSIS OF SWITCHING-MODE DC–DC REGULATORS

2000 ◽  
Vol 10 (02) ◽  
pp. 373-390 ◽  
Author(s):  
M. ALFAYYOUMI ◽  
A. H. NAYFEH ◽  
D. BOROJEVIC
Keyword(s):  
Closed Loop ◽  
Period Doubling ◽  
Input Voltage ◽  
Open Loop ◽  
Domain Model ◽  
Equilibrium Solutions ◽  
Modeling And Analysis ◽  
Proportional Integral ◽  
Switching Regulators ◽  
Switching Mode

The nonlinear dynamics of PWM DC–DC switching regulators operating in the continuous conduction mode are investigated. A quick review of the existing analysis techniques and their limitations are first presented. A discrete nonlinear time-domain model is then derived for open-loop DC–DC converters. This model is then extended for closed-loop regulator systems implementing any type of compensation scheme. The equilibrium solutions of the closed-loop system are then identified. The eigenvalues of the Jacobian matrix evaluated at the equilibrium solution are used to assess its stability. The methods developed are used to study the dynamic behavior of a DC–DC buck regulator implementing different types of compensation design: proportional, integral, proportional–integral, and proportional–integral–derivative type feedback control. A detailed bifurcation analysis of the dynamic solutions as a design or a control parameter is changed is presented. A period-doubling route to chaos is shown to exist in voltage-mode regulators, depending on the values of the parameters of the compensator and the input voltage. A further investigation of the behavior of the converter in the instability regions was carried out to improve the understanding of this interesting behavior.

scholarly journals Pengontrolan Kecepatan Rotor BLDC UAV Berdasarkan Hasil Identifikasi menggunakan Metode Regresi

2021 ◽  
Vol 9 (1) ◽  
pp. 114
Author(s):  
ERWANI MERRY SARTIKA, ◽  
MULIADY MULIADY ◽  
RUDI SARJONO ◽  
VINCENSIUS YUVENS
Keyword(s):  
Closed Loop ◽  
Maximum Error ◽  
Open Loop ◽  
Regression Method ◽  
Settling Time ◽  
Bldc Motor ◽  
Rotor Speed ◽  
Loop Control ◽  
Proportional Integral ◽  
Brushless Dc

ABSTRAKPenggunaan dan aplikasi motor Brushless DC cukup banyak di industri, namun masih cukup sulit untuk mengendalikannya. Pada penelitian sebelumnya telah dipelajari karakteristik parameter motor BLDC UAV menggunakan Metode Regresi untuk mengetahui hubungan antar parameter yang ada dalam sistem motor BLDC. Sinyal PWM merupakan salah satu yang menentukan kecepatan rotor dari BLDC. Pada penelitian ini identifikasi model motor BLDC hasil eksperimen digunakan untuk mengendalikan kecepatan rotor secara open loop dan closed loop. Pengendalian secara open loop menggunakan invers model hasil Metode Regresi menghasilkan kesalahan maksimal 3,77% untuk kecepatan rotor lebih dari 3500 rpm. Sedangkan pada pengendalian secara closed loop menggunakan model hasil Metode Regresi dan pengendali PI (Proportional Integral) dengan Kp = 1 dan Ki = 5, secara simulasi menghasilkan kecepatan rotor dengan settling time 1 detik.Kata kunci: motor BLDC, kecepatan rotor, identifikasi model, pengendalian ABSTRACTThe use and application of Brushless DC motors is quite a lot in the industry, but it is still quite difficult to control. In previous research the characteristics of UAV BLDC motor parameters using the regression method to determine the relation of the parameters in the BLDC motor system. The PWM signal is one that determines the rotor speed of the BLDC. In this study the identification of the BLDC motor model experimental results is used to control the rotor speed in open loop and closed loop. Control with open loop using the inverse model of the Regression Method produces a maximum error of 3.77% for rotor speeds of more than 3500 rpm. Whereas control with closed loop using the model of the Regression Method and PI (Proportional Integral) controller with Kp = 1 and Ki = 5, the simulation produces rotor speed with a settling time of 1 second.Keywords: BLDC motor, rotor speed, model identification, control

On closed-loop equilibrium strategies for mean-field stochastic linear quadratic problems

2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Optimal Control Problems ◽  
Mean Field ◽  
Open Loop ◽  
Time Inconsistency ◽  
Control Problems ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Equilibrium Strategies

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

scholarly journals Parallel Point Clouds: Hybrid Point Cloud Generation and 3D Model Enhancement via Virtual–Real Integration

2021 ◽  
Vol 13 (15) ◽  
pp. 2868
Author(s):  
Yonglin Tian ◽  
Xiao Wang ◽  
Yu Shen ◽  
Zhongzheng Guo ◽  
Zilei Wang ◽  
...  
Keyword(s):  
Point Cloud ◽  
Closed Loop ◽  
Real Data ◽  
Point Clouds ◽  
Autonomous Driving ◽  
Training Model ◽  
Labor Cost ◽  
Open Loop ◽  
Training Dataset ◽  
Data Annotation

Three-dimensional information perception from point clouds is of vital importance for improving the ability of machines to understand the world, especially for autonomous driving and unmanned aerial vehicles. Data annotation for point clouds is one of the most challenging and costly tasks. In this paper, we propose a closed-loop and virtual–real interactive point cloud generation and model-upgrading framework called Parallel Point Clouds (PPCs). To our best knowledge, this is the first time that the training model has been changed from an open-loop to a closed-loop mechanism. The feedback from the evaluation results is used to update the training dataset, benefiting from the flexibility of artificial scenes. Under the framework, a point-based LiDAR simulation model is proposed, which greatly simplifies the scanning operation. Besides, a group-based placing method is put forward to integrate hybrid point clouds, via locating candidate positions for virtual objects in real scenes. Taking advantage of the CAD models and mobile LiDAR devices, two hybrid point cloud datasets, i.e., ShapeKITTI and MobilePointClouds, are built for 3D detection tasks. With almost zero labor cost on data annotation for newly added objects, the models (PointPillars) trained with ShapeKITTI and MobilePointClouds achieved 78.6% and 60.0% of the average precision of the model trained with real data on 3D detection, respectively.

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