Getting Started with Aspen HYSYS Dynamics - · PDF file© 2012 Aspen Technology, Inc. All rights reserved Getting Started with Aspen HYSYS Dynamics Solving safety and operability challenges

© 2012 Aspen Technology, Inc. All rights reserved

Getting Started with Aspen HYSYS Dynamics Solving safety and operability challenges

Dr. Glenn Dissinger,

Product Director, Aspen Technology

Hosted by:

Ron Beck,

Product Marketing, AspenTech

Optimizing Operations Webinar

Sept 5, 2012

© 2012 Aspen Technology, Inc. All rights reserved |

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Ongoing Series of Technical Webinars Engineering Webinars for education and best practices

UPCOMING WEBINARS OF INTEREST:

Sept 5, 2012: Getting Started with Aspen HYSYS Dynamics

Sept 13, 2012 (Asia/Pacific time): Improved Heat Exchanger Design with aspenONE EDR Integrated with Process Modeling (Tom Ralston)

Sept 20, 2012: Improving Olefins Plant Feedstock Flexibility and “Window of Operation” Using Aspen Plus (Phil Edwards, SABIC UK)

Oct 24, 2012: Modeling Conversion of Carbon to Biomass in Algal Systems (Dr. Eric Dunlop, Pan Pacific)

Dec 12, 2012: Solid Phase Modeling in Specialty Chemicals (Ajay Lakshmanan)

OTHER TOPICS TO BE ANNOUNCED

A library of additional recent webinars on many engineering topics is available on the AspenTech public website


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Common Models & Data

aspenONE Integration

Support Manufacturing & Supply Chain

Conceptual Engineering

Basic Engineering

Detailed Engineering

aspenONE engineering Best-in-class engineering solutions in an integrated work flow

Aspen Simulation Workbook & Aspen Online Deployment

Aspen Petroleum Downstream & HYSYS Upstream

Aspen Equipment Design & Rating

Aspen Basic Engineering Aspen Capital

Cost Estimator (ACCE)

Aspen Plus Dynamics, ACM & Flare System & Energy Analyzer

Aspen Plus

Aspen HYSYS

Aspen Process Economic Analyzer (APEA)

Detailed Engineering


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Agenda

Introduction to Dynamic Simulation

– What Is It?

– Applications

Overview of HYSYS Dynamics

Demo – Transitioning a Steady-State Model to Dynamics

Q&A


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Process Dynamics

Consider the simple “bath tub” example • Steady-state: Fi = Fo

• Dynamic: dV/dt = Fi – Fo

where V=Vinit @ t=0

V=H*A

Fo = k * H

• Dynamic simulation predicts how a process and its associated control system will respond to various disturbances as a function of time

• Usage has been increasing

• Better tools

• Safety and quality demands have increased

• Today, steady-state design by itself is not enough!


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Applications of Dynamic Modeling & Simulation

Design / Analysis of Control Schemes

– Design the process and control system simultaneously

– Analyze and improve basic control strategies (e.g., fractionators, compressor surge, location of sensors, etc.)

– Pre-tune control loops

– Evaluate, develop and test APC scenarios (DMCplus)

Operability Engineering Studies

– Understand dynamic plant behavior, including upset propagation (e.g., slugging)

– Operability studies of highly-integrated processes

– Design / analysis of start-up, shutdown and process transition strategies

Hazard and Safety Studies

– Design / analysis of pressure relief and flare systems

– Safety studies

– Design / analysis of emergency shutdown systems

Operator Training

– DCS checkout

– Graphics functionality/operability of the operator consoles


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Agenda


– What Is It?

– Applications and Success Stories



Q&A


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What Does HYSYS Dynamics Offer?

Seamless transition from Steady State to Dynamic

Interactive environment

Rich choice between simple and detailed modeling

A comprehensive library of control and logical operations

Dynamics Assistant


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Steady State

Dynamic mode

Completely Integrated with HYSYS

Same program

Same GUI

Same thermodynamic models

All input data are shared

Steady state results can be used as initialization for dynamic simulation


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Rich choice between simple and detailed modeling options - Vessels

Simple Design Dynamics

A vessel with only the volume specified

Detailed Plant Dynamics

A vessel with

– Vessel elevation defined

– Nozzle positions defined

– Heat losses defined

– Entrainment modeling

– Level taps

or


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Rich choice between simple and detailed modeling options - Valves

Simple Design Dynamics

A linear valve with instant action

Detailed Plant Dynamics

An equal percentage valve with

– an actuator with linear rate

– an actuator with a defined fail mode

– a holdup

– an offset to simulate leaking

or


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Controllers Boolean Operations

Logical Operations

Comprehensive Library of Controller and Logical Operations

Used to replicate control logic and strategies used in the actual plant DCS system


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Dynamics Assistant

Can be VERY useful as a guide to see what changes it recommends However, use the Make Changes button with caution as its advice may NOT be what you want to do


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Agenda


– What Is It?

– Applications and Success Stories



Q&A


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Additional Data Required for a Dynamic Model

Dynamic

Model

Steady-State Model

Initial Model Input: • Thermodynamics • Components • Unit Operations • Flowsheet Construction

Dynamic Model

Additional Input: • Pressure-Flow Specs • Equipment Sizing • Controllers • Strip Charts


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Transitioning from Steady State to Dynamics

4 Steps are Needed

1. Pressure Flow Setup and Specifications

2. Equipment Sizing

3. Set up your Control Strategy

4. Set up your Strip Charts and Run the Model

©2009 AspenTech. All Rights Reserved.


Step 1: Pressure Flow Setup and Specifications


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Solver Basics

Aspen HYSYS Dynamics Solver is different from the Steady State Solver

Steady State – Pressures and Flows are not related, but can be set independently

Flow = 495 m3/s Pres = 130 kPa


Flow = 440 m3/s Pres = 120 kPa Flow = 440 m3/s

Pres = 375 kPa



No pressure drop across heat exchanger!


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Pressure Flow Solver in HYSYS Dynamics

Pressures and Flows are related, and can NOT be set independently



Flow = 440 m3/s Pres = 120 kPa Flow = 440 m3/s

Pres = 375 kPa



There must be a pressure drop to get a flowrate!!


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Pressure-Flow Relationship Concepts

All unit operation models are categorized in one of the following categories

– Pressure Node Operations – contain significant volume and calculate a pressure based on the holdup of vapor in the unit operation

– Resistance Equation Operations – calculate a pressure drop based on a resistance equation

P/F specifications MUST be set on all boundary streams


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Guidelines for Transitioning to Dynamics

1. Add a resistance unit operation (e.g., valve, pump, compressor) between all pressure nodes in the flowsheet

– Internal flow rates will be calculated by the pressure gradients throughout the flowsheet

2. One P/F specification should be made on each boundary stream (feeds and products)

– Make pressure specifications on boundary streams attached to process equipment that use a resistance equation to calculate flow rates (e.g., valves, pumps, compressor, heat exchangers

– Recommendation – Add valves to all boundary streams (You will use them for flow controllers anyway once you add the control

strategy to the dynamic model!)


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Ensuring Pressure Gradient in Model Guideline #1 – Add valves between pressure nodes

Valve added between two vessels


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Ensuring Pressure Gradient in Model Guideline #2 – Add valves on boundary streams


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Ensuring Pressure Gradient in Model Guideline #2 – Set pressure specification on boundary streams


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Best Practice - PFD Display of Dynamic P/F Specifications

Available from drop-down menu on PFD

Color Code • Green – Pressure specified • Yellow – Flow specified • Red – Pressure and Flow specified • Blue – None specified



Step 2: Equipment Sizing


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Size Matters in Dynamics!!

Consider the level control of a tank…..

“Noisy” feed flow

What impacts the stability of the outlet flow?


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Size Matters in Dynamics!!

Large tanks can mitigate disturbances


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Equipment sizing data can be entered on the Rating or Dynamics tab



Step 3: Setting Up Your Control Strategy


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Basics of Control Theory

A control system is designed to maintain stable process operations by compensating for disturbances

Key terms used by control engineers

– Process Variable (PV): Process variable that you want to maintain at a given operating point or set point

– Manipulated Variable (MV): Process variable that is changed by the controller

– Disturbance Variable (DV): A process variable which upsets a process and causes the control variables to move from the

desired set-points

Controls do what the process engineers can not


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Controller Library

PID Controller


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Basics of the PID Controller

The PID controller is the most used controller in the process industries

The basic PID equation is:

OP(t) = Kc E(t) + Kc /i (E(t)dt + Kcd dE(t)/dt

P - Proportional I - Integral D - Derivative

where:

OP(t) = controller output value

E(t) = error between controller setpoint and process variable

and the tuning parameters are:

Kc = controller gain

i = controller integral reset

d = controller derivative constant


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Key Input for the PID Controller Model

Controller Action

Controller Tuning Parameters


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Controller Tuning - Recommendations

The values below are recommended starting points for tuning control loops

System Kc

i (minutes) d (minutes)

Flow 0.1 0.2 0

Level 2 10 0

Pressure 2 2 0

Temperature 1 20 0



Step 4: Running Your Model


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Three Things To Consider Before Running Your Model

1. Set up strip charts

2. Integration step sizes and speed

3. Event Scheduler


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4 Steps are Needed

1. Pressure Flow Setup and Specifications

2. Equipment Sizing

3. Set up your Control Strategy

4. Set up your Strip Charts and Run the Model


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For more Aspen HYSYS Dynamics information

Aspen HYSYS Dynamics web page

– http://www.aspentech.com/products/aspen-hysys-dynamics.aspx

– White papers, case studies, tutorials, resources

Library of webinars-on-demand

– www.aspentech.com > events > webinar-on-demand

Coming soon (will be sent to all webinar participants):

– HYSYS Dynamics written getting-started-guide

– HYSYS Dynamics computer-based-training (CBT) module

AspenTech Support site

– Rich knowledge base of information, tips, technical support

– Training videos, viewlets and CBTs

– Technical bulletins

Aspen HYSYS LinkedIn group

– 2900 members; many discussions

http://www.aspentech.com/products/aspen-hysys-dynamics.aspx





http://www.aspentech.com/


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OPTIMIZE™ 2013 Global Conference

Join us in Boston for the industry’s must-attend event!

OPTIMIZE 2013 6 – 8 May 2013 The Westin Waterfront Hotel Boston, MA USA For more information, visit www.aspentech.com/agc

http://www.aspentech.com/agc


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Questions?


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What Next?

Get more information now

– Call your AspenTech account manager or

– Call Aspen Telesales Direct:

USA: +1-855-882-7736

EUROPE & MIDDLE EAST: +44-1189-226400

ASIA/PACIFIC and INDIA: +65-6395-3900

– Or email us at [email protected]

Contact info for today’s presenter

– [email protected]

mailto:[email protected]

Documents

Getting Started with Aspen HYSYS Dynamics - · PDF file© 2012 Aspen Technology, Inc. All rights reserved Getting Started with Aspen HYSYS Dynamics Solving safety and operability challenges