Tier 2Modulo 15NAMP Process Control and Process Integration 1 Created at Universidad de Guanajuato & École Polytechnique de Montréal Module 15: Process Control and Process Integration – Tier 2 Program for North American Mobility in Higher Education (NAMP) Introducing Process Integration for Environmental Control in Engineering Curricula (PIECE)

Tier 2Modulo 15NAMP Process Control and Process Integration 2 This module is divided in three essentials complements, it will demonstrate the relationship between the use of PI tools in order to design a process and the control strategies.

Tier 2Modulo 15NAMP Process Control and Process Integration 3  Tier one: Basic Concepts About Process Control  Tier Two: Use of PI tools and especially dynamic simulation to address control strategies  Tier Three: Analysis of a real process. Structure

Tier 2Modulo 15NAMP Process Control and Process Integration 4 Index:  Tier one: Comparison between Steady Sate and Dynamic State. Important Definitions about dynamic state. Dynamic Models.

Tier 2Modulo 15NAMP Process Control and Process Integration 5 Index:  Tier two: Relationship between Process Design and Process Control Dynamic Effect on recycle Structures.

Tier 2Modulo 15NAMP Process Control and Process Integration 6 Tier 2

Tier 2Modulo 15NAMP Process Control and Process Integration 7 Objective:  Understand the interaction between process design and process control.  Understand the effect of recycle structures on dynamic behavior. Tier 2

Tier 2Modulo 15NAMP Process Control and Process Integration 8 Process Control in a Integrated Perspective

Tier 2Modulo 15NAMP Process Control and Process Integration 9 Identification and creation of potential opportunities to satisfy societal needs and to generate profit. Any process starts with

Tier 2Modulo 15NAMP Process Control and Process Integration 10 Manufacturing process Natural Resources Basic Chemical products Basic Chemicals industrial Products Basic Chemical products Industrial Products Consumer Products

Tier 2Modulo 15NAMP Process Control and Process Integration 11 Process Creation The next step is

Tier 2Modulo 15NAMP Process Control and Process Integration 12 ? Process design starts with the synthesis of a process to convert raw material into desired products Feed Streams Product Streams

Tier 2Modulo 15NAMP Process Control and Process Integration 13 Process Flowsheet Is a diagrammatic representation of the process steps using icons to represent process units and arrows to represent connections among them Feed Streams Product Streams

Tier 2Modulo 15NAMP Process Control and Process Integration 14 It is common the presence of recycles (process integration) because its advantages to recover energy. However is important to know how they affect the dynamic properties. Simulation Steady State

Tier 2Modulo 15NAMP Process Control and Process Integration 15 Is a mathematical model of the process that attempts to predict how the process would behave if it were constructed or modified Simulation Steady Sate Simulation the operating conditions are changed to others ones in order to evaluate new operating sceneries Operating Condition New Operating Condition Feed Product

Tier 2Modulo 15NAMP Process Control and Process Integration 16 Having the process flowsheet the next step is to evaluate the process control configuration. ♣ Effect of the recycle in process dynamic  Effect of the heat integration in process dynamic.  How to control the process. How to control the process. Dynamic State Simulation allows to test different control strategies and to know the influence of changes in the process design on the dynamic behavior.

Tier 2Modulo 15NAMP Process Control and Process Integration 17 The role of Control Process in Process Design

Tier 2Modulo 15NAMP Process Control and Process Integration 18 Resiliency Analysis Controllability Analysis * RGA * Niderlinski Index * Condition Number * Relative Disturbance Gain * Disturbance Cost * Disturbance Condition Number Previous

Tier 2Modulo 15NAMP Process Control and Process Integration 19 Effect of recycle

Tier 2Modulo 15NAMP Process Control and Process Integration 20 Recycle Structures These structures are used often in process plants to return material for reprocessing and to recover energy from effluent streams trough heat exchanger.

Tier 2Modulo 15NAMP Process Control and Process Integration 21 Heat Recycle Fresh feed is heating using the stream leaving the reactor This stream goes trough a heat exchanger in order to recover heat

Tier 2Modulo 15NAMP Process Control and Process Integration 22 Block diagram for this system + G H2 (s) G R (s) G H1 (s) T 0 (s) T 1 (s) T R (s) T f (s) T 2 (s)

Tier 2Modulo 15NAMP Process Control and Process Integration 23 Now using block diagram algebra to determine el behavior of the integrated system transfer function is: Block Diagram Characteristic Equation Poles of overall system are different to the poles of the individual units. The stability of this system cannot be guaranteed even if each individual system is stable.

Tier 2Modulo 15NAMP Process Control and Process Integration 24 Now defining With RecycleWithout Recycle Gain Time Constant

Tier 2Modulo 15NAMP Process Control and Process Integration 25 Performing a Dynamic Simulation to know the dynamic behavior Time constant and gain have been increased in the reactor with recycle

Tier 2Modulo 15NAMP Process Control and Process Integration

Tier 2Modulo 15NAMP Process Control and Process Integration 27 Increase in T 0 Affects T f Affects T R The output is reinforced through the recycle exchanger There is a positive feedback Why ?

Tier 2Modulo 15NAMP Process Control and Process Integration 28 The time constant and the steady state gain of the overall system with recycle can be changed substantially from their values without recycle. Recycle can alter the stability and possibility for a periodic behavior of the overall system, because it affects the poles of the overall system. This effect should be considered when the process control is developed because the time constant is related with the speed of response of the process. According the previous slides

Tier 2Modulo 15NAMP Process Control and Process Integration 29 QUIZ

Tier 2Modulo 15NAMP Process Control and Process Integration The effect of a positive feedback is not desirable because : a) Its actions tends to increase the error from desired. b) Its action tends to reduce the error from desired.

Tier 2Modulo 15NAMP Process Control and Process Integration If time constant increases its value, it implies : a) A slow system´s response when changes on manipulated variables are made to produce changes on controllable variable. b) A faster system´s response when changes on manipulated variables are made to produce changes on controllable variable.

Tier 2Modulo 15NAMP Process Control and Process Integration 32 Correct Answer To continue, click on the figure

Tier 2Modulo 15NAMP Process Control and Process Integration 33  Try another Answer To continue, click on the figure

Tier 2Modulo 15NAMP Process Control and Process Integration 34 Correct Answer To continue, click on the figure

Tier 2Modulo 15NAMP Process Control and Process Integration 35  Try another Answer To continue, click on the figure

Tier 2Modulo 15NAMP Process Control and Process Integration 36 Now you have finished Tier 2