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 A New Graphical Technique for Energy Efficient Design of Heat Recovery System in Chemical/Refining Industries

2016 ◽  
Vol 4 (4) ◽  
pp. 33
Author(s):  
Dina Ahmed Kamel ◽  
Mamdouh Ayad Gadalla ◽  
Fatma Hanafy Ashour
Keyword(s):  
Heat Exchanger ◽  
Driving Forces ◽  
Process Integration ◽  
Minimum Energy ◽  
Pinch Analysis ◽  
Efficient Design ◽  
Heating And Cooling ◽  
Heat Exchanger Networks ◽  
Graphical Technique ◽  
Key Steps

Chemical processes are energy intensive industries; the majority of energy consumed in industrial processes is mainly used for heating and cooling requirements. This results in increasing the interest in obtaining the optimum design of the heat exchanger networks to reduce the energy consumption and face the growing energy crises. Most of the published literature over the last fifty years promotes the process integration technology as a main part of the process system engineering science. Graphical Pinch Analysis method normally includes two key steps, firstly obtaining the energy targets which include the minimum energy required for the HEN design, then designing the heat exchanger network (HEN). This paper introduces a new graphical approach for the design of new heat exchanger networks (HENs) based on pinch analysis rules. The HEN is represented on a simple graph, where the cold stream temperatures are plotted on the X-axis while the driving forces for each exchanger are plotted on the Y-axis. This graphical technique can describe the energy analysis problems in term of temperature driving force inside the heat exchanger, which is an important factor in the design process as the differences in these driving forces are involved in calculating the area of heat exchangers, and consequently affecting the cost.

scholarly journals Energy efficiency improvement in the system for drying baker`s yeast

2019 ◽  
Vol 38 (1) ◽  
pp. 115
Author(s):  
Aleksandar Kosta Anastasovski
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Process Integration ◽  
Waste Heat ◽  
Heat Energy ◽  
Production Costs ◽  
Main Task ◽  
Heat Process ◽  
Heat Exchanger Networks ◽  
Heat Energy Recovery

Drying processes are one of the main consumers of heat energy in production. Any decreases in heat consumption during the drying process will considerably decrease production costs. This study analyzes the high consumption of heat in the drying of baker`s yeast. The main task is to minimize the energy demand and lower the price of the final products with partial heat recovery. These changes will require system modifications. One of the most popular and effective methods that can be used in this case is heat process integration with Pinch Technology. In this study, a reference system was simulated with a mathematical model and analyzed for waste heat streams.This paper suggests the redesigning of a drying system for production of active dry yeast.  Selected streams that satisfy conditions for heat process integration were involved in the evaluation for a better solution. Two different scenarios were proposed as possible solutions. The suggested solutions are retrofit designs of Heat Exchanger Networks. These Heat Exchanger Networks include already installed heat exchangers as well as new heat transfer units. The selection of better design was made with economic analysis of investment. The proposed scenarios of the analyzed sub-system give improvement in heat energy recovery. The best determined solution reduces the cost and thus has the highest profitability, but not the highest heat energy recovery.

Optimum heat storage design for solar-driven absorption refrigerators integrated with heat exchanger networks

AIChE Journal ◽  
2013 ◽  
Vol 60 (3) ◽  
pp. 909-930 ◽  
Author(s):  
Luis Fernando Lira-Barragán ◽  
José María Ponce-Ortega ◽  
Medardo Serna-González ◽  
Mahmoud M. El-Halwagi
Keyword(s):  
Heat Exchanger ◽  
Heat Storage ◽  
Heat Exchanger Networks ◽  
Optimum Heat

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.

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