Synthesis and Retrofit Design of Operable Heat Exchanger Networks. 2. Dynamics and Control Structure Considerations

1994 ◽  
Vol 33 (7) ◽  
pp. 1738-1755 ◽  
Author(s):  
Katerina P. Papalexandri ◽  
Efstratios N. Pistikopoulos
Keyword(s):  
Heat Exchanger ◽  
Control Structure ◽  
Heat Exchanger Networks ◽  
Dynamics And Control ◽  
And Control ◽  
Retrofit Design

scholarly journals A SIMPLE FIVE-STEP METHODOLOGY TO DETERMINE CONTROLLABILITY OF HEAT EXCHANGER NETWORKS USING STEADY-STATE INFORMATION

2011 ◽  
Author(s):  
Rodolfo Tellez ◽  
William Y. Svrcek ◽  
Brent R. Young
Keyword(s):  
Steady State ◽  
Heat Exchanger ◽  
Process Integration ◽  
Plant Design ◽  
State Information ◽  
Step Procedure ◽  
Heat Exchanger Networks ◽  
Propose Control Strategy ◽  
Optimum Heat ◽  
And Control

Process integration design methodologies have been developed and introduced to synthesise an optimum heat exchanger network (HEN) arrangement. However, controllability issues are often overlooked during the early stages of a plant design. In this paper we present a five-step procedure that involves the use of multivariable disturbance and control analyses based solely on steady-state information and with the purpose to assess process design developments and to propose control strategy alternatives appropriate and suitable for a HEN.

scholarly journals Stability of Optimal Closed-Loop Cleaning Scheduling and Control with Application to Heat Exchanger Networks under Fouling

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1623
Author(s):  
Federico Lozano Santamaria ◽  
Sandro Macchietto
Keyword(s):  
Heat Exchanger ◽  
Closed Loop ◽  
Operating Cost ◽  
Optimization Procedure ◽  
Loop Model ◽  
Loop Scheduling ◽  
Loop Optimization ◽  
Trade Offs ◽  
Heat Exchanger Networks ◽  
And Control

Heat exchanger networks subject to fouling are an important example of dynamic systems where performance deteriorates over time. To mitigate fouling and recover performance, cleanings of the exchangers are scheduled and control actions applied. Because of inaccuracy in the models, as well as uncertainty and variability in the operations, both schedule and controls often have to be revised to improve operations or just to ensure feasibility. A closed-loop nonlinear model predictive control (NMPC) approach had been previously developed to simultaneously optimize the cleaning schedule and the flow distribution for refinery preheat trains under fouling, considering their variability. However, the closed-loop scheduling stability of the scheme has not been analyzed. For practical closed-loop (online) scheduling applications, a balance is usually desired between reactivity (ensuring a rapid response to changes in conditions) and stability (avoiding too many large or frequent schedule changes). In this paper, metrics to quantify closed-loop scheduling stability (e.g., changes in task allocation or starting time) are developed and then included in the online optimization procedure. Three alternative formulations to directly include stability considerations in the closed-loop optimization are proposed and applied to two case studies, an illustrative one and an industrial one based on a refinery preheat train. Results demonstrate the applicability of the stability metrics developed and the ability of the closed-loop optimization to exploit trade-offs between stability and performance. For the heat exchanger networks under fouling considered, it is shown that the approach proposed can improve closed-loop schedule stability without significantly compromising the operating cost. The approach presented offers the blueprint for a more general application to closed-loop, model-based optimization of scheduling and control in other processes.

Control structure design for optimal operation of heat exchanger networks

AIChE Journal ◽  
2007 ◽  
Vol 54 (1) ◽  
pp. 150-162 ◽  
Author(s):  
Veerayut Lersbamrungsuk ◽  
Thongchai Srinophakun ◽  
Sridharakumar Narasimhan ◽  
Sigurd Skogestad
Keyword(s):  
Heat Exchanger ◽  
Control Structure ◽  
Optimal Operation ◽  
Structure Design ◽  
Heat Exchanger Networks

Dynamics and control of the Czochralski process II. Objectives and control structure design

1988 ◽  
Vol 91 (1-2) ◽  
pp. 199-217 ◽  
Author(s):  
Michael A. Gevelber ◽  
George Stephanopoulos ◽  
Michael J. Wargo
Keyword(s):  
Control Structure ◽  
Structure Design ◽  
Dynamics And Control ◽  
And Control ◽  
Czochralski Process

scholarly journals Unmanned cruciform winged glider dynamics and control

2018 ◽  
pp. 55-60
Author(s):  
M. A. Polishchuk ◽  
M. V. Polishchuk
Keyword(s):  
Control Structure ◽  
Longitudinal Axis ◽  
Operating Conditions ◽  
Flight Performance ◽  
Autonomous Flight ◽  
Flight Phase ◽  
Ratio Effect ◽  
Dynamics And Control ◽  
And Control ◽  
Wing Aspect Ratio

Tha paper focuses on the problems of unmanned cruciform winged glider dynamics and control in autonomous flight conditions, and studies the wing aspect ratio effect on its flight performance. The winged glider control structure in the longitudinal and lateral axes is proposed. We carried out a comparative analysis of the ballistic flight ranges of models of different configurations, as well as the flight ranges of models of different configurations in the operating conditions of the control system of the proposed structure. As a result, the structure of the unmanned winged glider targeting system is proposed. The targeting system in the longitudinal axis, unlike the samples used in currently operating models, consists of two subsystems responsible for the unmanned winged glider best range gliding at the first flight phase and the direct aimpoint guidance at the second, i.e. final, flight stage

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