scholarly journals A Parallel Processing Approach to Dynamic Simulation of Ethylbenzene Process

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1386
Author(s):  
Junkai Zhang ◽  
Zhongqi Liu ◽  
Zengzhi Du ◽  
Jianhong Wang
Keyword(s):  
Parallel Computing ◽  
Dynamic Simulation ◽  
Process Simulation ◽  
Chemical Process ◽  
Process Model ◽  
Chemical Processes ◽  
Data Driven ◽  
Computer Performance ◽  
Speed Up ◽  
General Dynamic

Parallel computing has been developed for many years in chemical process simulation. However, existing research on parallel computing in dynamic simulation cannot take full advantage of computer performance. More and more applications of data-driven methods and increasing complexity in chemical processes need faster dynamic simulators. In this research, we discuss the upper limit of speed-up for dynamic simulation of the chemical process. Then we design a parallel program considering the process model solving sequence and rewrite the General dynamic simulation & optimization system (DSO) with two levels of parallelism, multithreading parallelism and vectorized parallelism. The dependency between subtasks and the characteristic of the hottest subroutines are analyzed. Finally, the accelerating effect of the parallel simulator is tested based on a 500 kt·a−1 ethylbenzene process simulation. A 5-hour process simulation shows that the highest speed-up ratio to the original program is 261%, and the simulation finished in 70.98 s wall clock time.

scholarly journals Application of Sequential Quadratic Programming Based on Active Set Method in Cleaner Production

2021 ◽  
Author(s):  
Li Xia ◽  
JianYang Ling ◽  
Zhen Xu ◽  
Rongshan Bi ◽  
Wenying Zhao ◽  
...  
Keyword(s):  
Quadratic Programming ◽  
Process Simulation ◽  
Sequential Quadratic Programming ◽  
Chemical Process ◽  
Simulation Software ◽  
Active Set ◽  
Active Set Method ◽  
General Chemical ◽  
Optimization Function ◽  
Speed Up

Abstract On the platform of general chemical process simulation software(it was named Optimization Engineer, OPEN), a general optimization algorithm for chemical process simulation is developed using C++ code. The algorithm is based on Sequential Quadratic Programming (SQP). We adopt the activity set algorithm and the rotation axis algorithm to generate the activity set to solve the quadratic programming sub-problem. The active set method can simplify the number of constraints and speed up the calculation. At the same time, we used limited memory BFGS algorithm (L-BFGS) to simplify the solution of second derivative matrix. The special matrix storage mode of L-BFGS algorithm can save the storage space and speed up the computing efficiency. We use exact penalty function and traditional step-size rule in the algorithm. These two methods can ensure the convergence of the algorithm, a more correct search direction and suitable search step. The example shows that the advanced optimization function can meet the requirements of General Chemical Process Calculation. The number of iterations can reduce by about 6.0% . The computation time can reduce by about 6.5% . We combined this algorithm with chemical simulation technology to develop the optimization function of chemical engineering simulation. This optimization function can play an important role in the process optimization calculation aiming at energy saving and green production.

Non Linear State and Parameters Estimation in Chemical Processes: Analysis and Improvement of Three Estimation Structures Applied to a CSTR

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Héctor Botero ◽  
Hernán Álvarez
Keyword(s):  
Parameter Estimation ◽  
Chemical Process ◽  
Chemical Processes ◽  
The State ◽  
Convergence Speed ◽  
Parameters Estimation ◽  
State Variables ◽  
Input Output ◽  
On Line ◽  
Linear State

This paper proposes a new composite observer capable of estimating the states and unknown (or changing) parameters of a chemical process, using some input-output measurements, the phenomenological based model and other available knowledge about the process. The proposed composite observer contains a classic observer (CO) to estimate the state variables, an observer-based estimator (OBE) to obtain the actual values of the unknown or changing parameters needed to tune the CO, and an asymptotic observer (AO) to estimate the states needed as input to the OBE. The proposed structure was applied to a CSTR model with three state variables. With the proposed structure, the concentration of reactants and other CSTR parameters can be estimated on-line if the reactor and jacket temperatures are known. The procedure for the design of the proposed structure is simple and guarantees observer convergence. In addition, the convergence speed of state and parameter estimation can be adjusted independently.

scholarly journals Special Issue: Green Sustainable Chemical Processes

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1097
Author(s):  
Francisco J. Hernández Fernández ◽  
Antonia Pérez de los Ríos
Keyword(s):  
Green Chemistry ◽  
Chemical Process ◽  
Process Engineering ◽  
Chemical Processes ◽  
Sustainable Chemistry ◽  
Special Issue

Sustainable chemical process engineering results from applying the principles of green chemistry or sustainable chemistry to chemical process engineering [...]

Modeling of a Steam Turbine Including Partial Arc Admission for Use in a Process Simulation Software Environment

2011 ◽  
Author(s):  
Eric Liese
Keyword(s):  
Steam Turbine ◽  
Process Simulation ◽  
Process Model ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
State Variables ◽  
Steam Turbines ◽  
Software Environment ◽  
Last Stage

A dynamic process model of a steam turbine, including partial arc admission operation, is presented. Models were made for the first stage and last stage, with the middle stages presently assumed to have a constant pressure ratio and efficiency. A condenser model is also presented. The paper discusses the function and importance of the steam turbines entrance design and the first stage. The results for steam turbines with a partial arc entrance are shown, and compare well with experimental data available in the literature, in particular, the “valve loop” behavior as the steam flow rate is reduced. This is important to model correctly since it significantly influences the downstream state variables of the steam, and thus the characteristic of the entire steam turbine, e.g., state conditions at extractions, overall turbine flow, and condenser behavior. The importance of the last stage (the stage just upstream of the condenser) in determining the overall flowrate and exhaust conditions to the condenser is described and shown via results.

SDG-based Model Validation in Chemical Process Simulation

2013 ◽  
Vol 21 (8) ◽  
pp. 876-885 ◽  
Author(s):  
Beike ZHANG ◽  
Xin XU ◽  
Xin MA ◽  
Chongguang WU
Keyword(s):  
Model Validation ◽  
Process Simulation ◽  
Chemical Process
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