Steady-State and Dynamic Modeling of the Basell Multireactor Olefin Polymerization Process

2011 ◽  
Vol 50 (1) ◽  
pp. 322-331 ◽  
Author(s):  
Zu-Wei Zheng ◽  
De-Pan Shi ◽  
Pei-Lin Su ◽  
Zheng-Hong Luo ◽  
Xiao-Jun Li
Keyword(s):  
Steady State ◽  
Dynamic Modeling ◽  
Olefin Polymerization ◽  
Polymerization Process

Steady-state and dynamic modeling of a gas absorber-stripper system

1985 ◽  
Vol 24 (3) ◽  
pp. 288-295 ◽  
Author(s):  
Martin M. Suenson ◽  
Christos Georgakis ◽  
Lawrence B. Evans
Keyword(s):  
Steady State ◽  
Dynamic Modeling

A hemodynamic model representation of the dog lung

1991 ◽  
Vol 70 (1) ◽  
pp. 15-26 ◽  
Author(s):  
S. T. Haworth ◽  
J. H. Linehan ◽  
T. A. Bronikowski ◽  
C. A. Dawson
Keyword(s):  
Steady State ◽  
Dynamic Modeling ◽  
Power Law ◽  
Transmural Pressure ◽  
Morphometric Data ◽  
Pressure Flow ◽  
Average Ratio ◽  
Vascular Bed ◽  
Hemodynamic Model ◽  
Arteries And Veins

The published morphometric data from human, cat, and dog lungs suggest that the power-law relationships between the numbers (Na and Nv) and diameters (Da and Dv) of arteries and veins and between the lengths (La and Lv) and diameters of the arteries and veins could be used as scaling rules for assigning dimensions and numbers to the intrapulmonary vessels of the arterial and venous trees of the dog lung. These rules, along with the dimensions of the extrapulmonary arteries and capillary sheet and the distensibility coefficients of the vessels obtained from the literature, were used to construct a steady-state hemodynamic model of the dog lung vascular bed. The model can be characterized approximately by 15 orders of arteries with Na approximately 2.07 Da-2.58 and 13 orders of veins with Nv approximately 2.53 Dv-2.61. For the intrapulmonary vessels (orders 1–12), La approximately 4.85 Da1.01, and Lv approximately 6.02 Da1.07. The average ratio of the numbers of vessels in consecutive orders is approximately 3.2 for the arteries and veins. These arterial and venous trees are connected by the capillary sheet with an undistended thickness of approximately 3.5 microns and an area of 33 m2. The average distensibility (% increase in diameter over the undistended diameter/Torr increase in transmural pressure) for the model arteries and veins is approximately 2.4%/Torr, and the distensibility of the capillary sheet (% increase in thickness over the undistended thickness/Torr increase in transmural pressure) is approximately 3.6%/Torr. The calculated arterial-capillary-venous volumes and compliances of the model agree well with experimental estimates of these variables in dogs. In addition, the model appears consistent with certain aspects of the pressure-flow relationships measured in dog lungs. The model appears to be a useful summary of some of the available data on pulmonary morphometry and vessel properties. It is anticipated that the model will provide the basis for dynamic modeling of the dog lung in the future.

Pseudo-Dynamic Modeling to Evaluate a Remote Gas-to-Liquids Process

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Glen Hay ◽  
John Nighswander
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Model Development ◽  
Liquid Fuels ◽  
Sensitivity Analyses ◽  
Small Scale ◽  
Process Viability ◽  
Gas To Liquids ◽  
Steady State Simulation

A project team was given the task of evaluating various technology options for design of a small-scale gas-to-liquids (GTL) process operated remotely at or near an individual gas source. For this study, small-scale plants were considered those producing between 100 and 500 barrels per day of liquid fuels. In addition, being remote enforced limitations on utility sources available to the plant site such as water and grid power. A secondary goal was development of a dynamic model of the plant to use in operator training. To accomplish these objectives, the authors investigated the suitability of a process-simulation application. The conceptual design of the GTL unit included many different possibilities, such as front-end design, back-end design, heat integration, and recycling of materials. Complications associated with plant start-up and shutdown, utilities, process reliability, and economics were included in the decision-making process. The authors present selective results from a steady-state model and sensitivity studies. Considerations for the development of the dynamic model included both a fully rigorous dynamic model and a pseudo-dynamic steady-state-based model; results of the latter model are provided. The study concluded that an industrial steady-state simulation tool provided sufficient flexibility to complete the material and energy-balance calculations, sensitivity analyses, and pseudo-dynamic modeling. This study yielded significant insights into the importance of model assumptions and their impact on the overall process viability. The pseudo-dynamic model also provided insight for improving the process control design. During the work completed the authors determined that the object-oriented structure adopted for the model enabled an efficient, rapid model development.

Toward Controlling the Metallocene/Methylaluminoxane-Catalyzed Olefin Polymerization Process by a Computational Approach

2015 ◽  
Vol 34 (14) ◽  
pp. 3586-3597 ◽  
Author(s):  
Mikhail S. Kuklin ◽  
Janne T. Hirvi ◽  
Manfred Bochmann ◽  
Mikko Linnolahti
Keyword(s):  
Olefin Polymerization ◽  
Computational Approach ◽  
Polymerization Process

Dynamic Modeling and Analysis of Tank Vehicle under Braking Situation

2013 ◽  
Vol 694-697 ◽  
pp. 176-180
Author(s):  
Ying Wan ◽  
Li Mai ◽  
Zhi Gen Nie
Keyword(s):  
Steady State ◽  
Dynamic Modeling ◽  
Transient State ◽  
Equivalent Model ◽  
Vehicle Model ◽  
Matlab Simulink ◽  
Modeling And Analysis ◽  
Braking Performance ◽  
Pitch Motion ◽  
Vehicle System

Considering the instability of the direction dynamics of tank vehicle system under braking maneuver, the longitudinal equivalent model of liquid was formulated with consideration of both the steady-state and the transient state dynamics of the liquid. The Matlab/simulink program of the liquid was built and was combined with the vehicle model in Trucksim software to simulate and analyze the motion of the liquid cargo centroid and its dynamical effects on the vehicle under braking maneuver. It is observed that the liquid cargo slosh motion in tank vehicles has significant influences on braking performance, pitch motion and perpendicular motion of the vehicle. The results of this paper have significant help for studies on dynamics of vehicle tankers under braking maneuver and ensurement of braking stability and security.

scholarly journals Dynamic Modeling of HVDC for Power System Stability Assessment: A Review, Issues, and Recommendations

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4829
Author(s):  
Tarek Abedin ◽  
M. Shahadat Hossain Lipu ◽  
Mahammad A. Hannan ◽  
Pin Jern Ker ◽  
Safwan A. Rahman ◽  
...  
Keyword(s):  
Steady State ◽  
Dynamic Modeling ◽  
Direct Current ◽  
Current Source ◽  
Computational Cost ◽  
Operating Conditions ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Stability Assessment

High-voltage direct current (HVDC) has received considerable attention due to several advantageous features such as minimum transmission losses, enhanced stability, and control operation. An appropriate model of HVDC is necessary to assess the operating conditions as well as to analyze the transient and steady-state stabilities integrated with the AC networks. Nevertheless, the construction of an HVDC model is challenging due to the high computational cost, which needs huge ranges of modeling experience. Therefore, advanced dynamic modeling of HVDC is necessary to improve stability with minimum power loss. This paper presents a comprehensive review of the various dynamic modeling of the HVDC transmission system. In line with this matter, an in-depth investigation of various HVDC mathematical models is carried out including average-value modeling (AVM), voltage source converter (VSC), and line-commutated converter (LCC). Moreover, numerous stability assessment models of HVDC are outlined with regard to stability improvement models, current-source system stability, HVDC link stability, and steady-state rotor angle stability. In addition, the various control schemes of LCC-HVDC systems and modular multilevel converter- multi-terminal direct current (MMC-MTDC) are highlighted. This paper also identifies the key issues, the problems of the existing HVDC models as well as providing some selective suggestions for future improvement. All the highlighted insights in this review will hopefully lead to increased efforts toward the enhancement of the modeling for the HVDC system.

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