real-time optimization at us chemical utilities plant ... · chemical utilities plant reduces...

Real-time Optimization at US Chemical Utilities Plant Reduces Operating Costs

Fabian Robin

Marcelo Carugo

[File Name or Event]Emerson Confidential27-Jun-01, Slide 2

IntroductionIntroduction

• The Chemical Complex

• The Utilities Plant

• The Challenge

– The Need for an Optimizer

– The Solution

• The AMS Optimizer Application

• Project Execution & Benefits Audit

• Business Results

• Summary

• Questions/Comments


The Chemical Complex The Chemical Complex

• There are 15 manufacturing units located within six manufacturing groups

• The site produces a wide range of industrial chemicals that are used as catalysts and intermediates for the manufacture of hundreds of everyday consumer items

• Some chemicals manufactured are used by neighboring industrial plants to make their own products

• They also purchases some chemicals from neighboring plants for use on site.


The Utilities PlantThe Utilities Plant

• The utilities department is responsible for supplying all steam and power requirements on the site and managing the associated contracts.

• Utilities manage the contracts for natural gas supply, steam purchase & power purchase/sale.



• Key equipment:

– 2 Cogen units (one with supplemental firing)

– 4 fired boilers

– 1 steam turbine generator with steam extraction

– 3 steam headers at different pressures


Real-Time Optimizer - Project LifecycleReal-Time Optimizer - Project Lifecycle• Project Initiation & Justification

• Project Implementation

– Offline Model Build

– Offline Optimizer

– Online Open-Loop Optimizer

– Online Closed-Loop Optimizer

Benefits evaluated before moving to the next stage of the project

PLANT

OPTIMIZER

Off-Line

PLANT

OPTIMIZER

Open-Loop

PLANT

OPTIMIZER

Closed-Loop



• Operational Complexities

– The boilers are capable of firing a variety of fuel types including natural gas and one or more auxiliary fuels generated on the site

– Operating ranges for each equipment changes when it is firing a different mix of fuels

– The site is contracted to purchase a minimum amount of steam from a neighboring plant & the minimum amount will vary depending on the supplier’s operating conditions

– Gas turbines employ evaporative cooling & wet gas compression as peak power-demand shaving strategy


The ChallengeThe Challenge

• The Need for an Optimizer

– Complex plant and continuously changing demands

– Opportunity to find the optimum balance between steam generated and purchased

– Ever increasing cost of fuel and power

– Tool is required to enable sustained beneficial economic decisions on plant operation in real-time

• The Solution

– AMS™ Suite: Real-Time Optimizer selected to generate online, real-time recommendations to the plant operators on the most economical operation of the plant


The AMS Optimizer ApplicationThe AMS Optimizer Application

• The Process Models– Includes models of all key process operating equipment

– Models of each unit include all parameters that affect the actual operation of the unit (e.g. effect of ambient condition on gas turbine base load)

– Actual process measurements are used to fit the performance curves for each equipment so that model reflects the actual behavior of each unit thus accounting for any deviation from design

– Boiler and Gas Turbine models include the mixed fuel burning capabilities of the actual units.

– Contracts are modeled for all cost and revenue items:

• Natural Gas Purchase

• Steam Purchase

• Electricity purchase/sale



• Optimizer Objective– For the current total steam and power demand:

• Minimize the total operating cost

• Maximize auxiliary fuel burning (when available)

– By

• Choosing optimal Boiler Steam generation (& import) rates

• Choosing optimal Steam Turbine power generation rate

• Choosing optimal Gas turbine power generation rate

– Taking into account, all economic considerations which come to bear on the plant operation including:

• Fuel (natural gas) price (auxiliary fuels are supplied to utilities at no additional cost to Company)

• Loss due to steam venting

• Steam purchase price

• Power purchase price



• Supplied application consists of:

– Online Optimization System

– Offline Optimization Tool



• Online optimization system– Open-loop implementation

– Optimizer runs automatically every 5 minutes using live process data

– Results are displayed in Aspen Process Explorer screen for implementation by the operators

– Optimizer manipulates defined operating handles in the process model

– Equipment model performance is automatically tuned online to ensure that model behavior is always consistent with the actual unit operation



• Offline optimization tool

– Based on the same core models as the online optimization system

– Developed in Microsoft™ Excel Interface

– Used for ad-hoc runs for evaluation of “what-if” scenarios e.g.:• Different equipment line-up

• Firing different fuels in boilers

• Boiler fouled/clean (adjusting boiler efficiency)



• Optimization System Architecture– Asynchronous processes

running online.

– Model includes:• Utilities plant

• Plant demands & constraints

• Plant Economics

– Data is read in real-time from the plant InfoPlus data historians

– Optimizer runs every 5 minutes in open-loop mode

– Optimizer results are archived in the site InfoPlus historian and displayed on the user interface (Aspen Process Explorer)

Engineering Interface

Plant Model

Site Data Historian

Offline

Optimiser

AMS Process Manager

Model database

Data conditioning & validation (AMS Data Manager)

Online User Interface

Offline Tool Interface

Online Optimiser

Model Updating

Plant Data Economic Data

InfoPlus

Optimizer Results

Local Data Server (PI)


Project Execution & Benefits AuditProject Execution & Benefits Audit

• Optimizer was designed, built and installed on site in 5 months, according to plan

• System went live after a 4-week commissioning period

Kick off

Design

System Build

Commissioning

Benefits Audit

Close-Out & Support

M5M4M3M2M1 M6

Design Approval

Interim Site Acceptance

Final Acceptance



• Project Phases– Kick-Off: Emerson team visit site

for admin/technical meetings & data collection

– Design Phase: System designs and test specification produced and reviewed with Company

– Build Phase: Optimization system built & tested and installed on site via remote link from Emerson.

– Site Commissioning: Emerson team on site for final model tuning and system review with Company, and delivering training to Operations team

– Benefits Audit: System goes live and operators are trained. Data is collected before and after system goes live to measure recovery of benefits

Kick off

Design

System Build

Commissioning

Benefits Audit

Close-Out & Support

M5M4M3M2M1 M6

Design Approval

Interim Site Acceptance

Final Acceptance



• Online Optimizer Benefits Audit– Baseline opportunity (deviation

in operating cost between actual and optimum operation) is calculated using historical plant data for a 6 month period

– Specific baseline is calculated using data when optimizer is running online but results are not being implemented

– Operators given hands-on training on use of optimizer and optimizer goes live

– Final measurement taken and cost deviation is recalculated to determine open-loop system benefit

– Benefits recovery is ratio of available benefit in Open-Loop (4) and Specific Baseline (2) periods

– Benefits recovery factor is applied to Baseline opportunity (1) to determine annualized system benefit

Opportunity Value(Optimiser Directed

Operation)

Opportunity Value(Current

Operation)

Optimiser Benefit

How the plant would have been operated without

the optimiser

Current operating cost

Operating cost at optimum

Operating Cost$/h

Time (Weeks)Specific Baseline Period

Open-Loop Operation

PeriodTraining Period & initial use


Business ResultsBusiness Results

• Audited benefit of over $612,000 /yr from the online AMS Optimizer

• AMS Optimizer was used to quantify losses due to required repair work on the burners in one of the boilers

• AMS Optimizer now forms part of the core decision making tools in the normal operation of the utilities plant equipment

Plant Type:Site UtilitiesCo-generation

Scope:Online OptimizerOffline Tool


Energy Optimization Example -Freeport ChemicalEnergy Optimization Example -Freeport Chemical

• Project: Consulting and Real-Time Optimizerto address

– 4 cogen plants with 12 Gas Turbines 7 Steam Turbines & 2 Fired Boilers producing over 1200 MW of power

– Major issue was rapid price changes

• Result:

– Optimally respond to energy price and demand changes

– Predict cost of operating degraded equipment

– Online Selection Optimizer to identify optimal equipment line up

– $ 5.3M per annum in benefits across 4 sites


Access results for each model/optimizer process on plant-by-

plant basis

View optimizer status and performance data

View results on per-equipment basis

View key performance results on summary screens


….and these are the corresponding model

predicted values

This overview screen displays

results for a specific plant

This column displays equipment name with key control

variables

This column displays variables on/off flags

These are the lower limit

values for the variables

These are the upper limit values for the

variables

These are current “live” measured

values…

These are the optimizer setpoints

This section displays the

optimizer status


The overview screen displays specific

equipment resultsThe results layout at

each level is the same for ease of use.

Key Performance Indicators (KPIs)

are also displayed

HRSG Steam results shown

here


This trend shows the current and

optimized operating cost

This line shows the actual operating cost using the optimizer

This line is the operating cost without using the optimizer.

The result across the 4 sites is an improvement

of $5.3M per annum


SummarySummary

• Complex utilities plant supplying steam and electricity to meet site demands

• Boilers capable of firing multiple fuels

• Complex process economics and contracts

• Tool required to make real-time recommendations of most economical operation

• AMS Optimizer solution implemented

• Solution was built and delivered to site according to plan (within 5 months) thus enabling quick realization of benefit for Company


The EndThe End

• Any Questions / Comments?

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