Integrated process optimization

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Analysis Tools for Integrated Analysis Tools for Integrated Process Optimization: Energy, Process Optimization: Energy,

Emissions, and ThroughputEmissions, and Throughput

33rd World Energy Engineering CongressWashington, DC

December 8-10, 2010

J D Kumana, MS ChEKumana & Associates, Houston, [email protected] (281) 437-5906

2Kumana & Associates, Houston, Texas © 2010

Outline

Background

PEO Methodology

Analysis Tools

Case Study - example

NOTE: “PEO” is a Trademark of ETSI Inc, Candler, NCIt stands for “Process Energy Optimization”

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Process Inputs and Outputs

UTILITYSYSTEM

MFGPROCESS

WASTETREATMENTELEC

FUEL

ELEC?

RAW MATGHG

PRODUCT

EFFLUENTDISCHARGE

ENERGY

CONTROLLABLE PARAMETERS• RAW MAT YIELDS

• REACTION KINETICS• UNIT OPERATIONS

• RECYCLE POINTS & RATES• ENERGY CONSUMPTION

PROCESS MODS

HEAT REC + CHP OPT


Impact on Profits

GHG EMISSIONS

ENERGY COST

WASTE TREATMENT

THROUGHPUT OR CAPACITY

YIELD + KINETICS

ENERGY EFF (SUPPLY)

ENERGY EFF (USAGE)

OPTIMUM RECYCLE

UNIT OPS

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Ideally, we should consider both Process and Energy on Integrated Basis

PROCESS MODSBIGGER IMPACT, BUT HIGHER CAP

COST + FINITE POTENTIAL RISK

ENERGY EFFICIENCYSMALLER IMPACT, BUT LOWER CAP

COSTS & ALMOST ZERO RISK


NOT

MY

JOB

STEAM

POWERELECUTILITY

PARADIGM: Utilities available instantaneously at ZERO costRESULT: Waste Energy in both Process & CHP System

R1

R2 SEP

F1

F2

P1

P2

Y

Process Engineer’s Viewpoint

4


B1 B2

DA

HRSG

C

Y

GT

condensate

BD

NOTMY

JOB

PARADIGM: Must supply demand at ANY CostRESULT: High Flexibility, Low Efficiency

Utility Engineer’s Viewpoint


EconomicEnvironment

CHPSystemProcess

• Energy• Emissions• Capacity

Integrated Viewpoint

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Process Energy Optimization

Using Energy (fuel + power) to

identify and exploit profitable

opportunities for process

efficiency improvement


PEO Integrates Process and Energy

Energy Supply,Conversion, &

Distribution Systems

Waste Collection,Reduction, Recovery,

& Discharge

Raw Mat’ls:Feed Stocks,

Coal, etc.

FinishedChemical Products

Chemical Plant“Processing”

Steps (see PFD)

A “high level” view of the Process and Energy Systems

PEOTM looks at the Process and Energy Systems as ONEUnified System

“We had never suspected that using energy differently can improve the process”.

David Broad, Site Mgr. BASF

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PEO uses Financial and Technical Models to directly link Engineering w/ Economics

An Engineering Model A Financial Model

THE SYSTEM(EQUIPMENT)

THE PROCESS

¨TEMPERATURES, ETC.¨PRACTICES of PEOPLE¨ TECHNOLOGY

THE BUSINESS UNIT

Power Plant Cost

Center

RAWMATERIALS

ENERGY

SCRAP

DEPRECIATION,TAXES, INSURANCE $

LABOR $

OTHER $

ENERGY $

SCRAP $

NETSALES $

RAW MAT’LEXPENSE $

REWORK

OTHER

LABOR

GROSSSALES $

PROFIT $

G&A andSELLINGEXP$

RETURNS &DISCOUNTS $

REWORK $

• WASTEWATER TREATMENT $,• AIR EMISSIONS $• SOLID WASTEDISPOSAL $

ENVIRONMENTALEMISSIONS

FINISHEDPRODUCT

Optimization Links-- “X% What ifs”: What is the annual K$/yr saving from a 1% or 10% annual improvement in product output, yields, quality, maintenance

effectiveness, operator productivity and energy performance?

Optimization links ?


PEOTM Methodology

Documentation - process & econ. modelsCorrect product/waste & utility pricingIdentify major $ impacts on Bottom Line, using sensitivity analysis (What If?)Focus on Critical Cost Issues (CCIs)3-phase approach

• Level 1 – rules of thumb, ball park economics • Level 2 – prelim calculations, conceptual design• Level 3 – detailed calcs, vendor quotes

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PEO – Key Features

Integrated holistic analysis3-phase approach (increasing levels of effort and accuracy)Collaborative Effort Consultant plays “coach/facilitator” role at Level 1Immediate ResultsImplementation Road MapThorough documentationPlant Ownership and Accountability (KPIs)


Technical Tool Kit

“COST FLOW” DIAGRAMS for CCIsSTRUCTURED BRAIN-STORMING

PFDs and HMB SIMULATION MODELSOPERATIONAL IMPROVEMENTSEQUIPMENT UPGRADESPINCH ANALYSIS

• PROCESS MODS – higher capacity & yields, less waste• OPTIMIZED HEAT RECOVERY• OPTIMIZED CHP STRUCTURE

ON-LINE UTILITIES MANAGEMENT

Level 1

Levels 2 & 3

Focus of THIS presentation

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Example of 1-line Cost Flow Diagram

Utilities: Major Chemical Plant site, Texas

#1 #2 #3 #4 #5 #6

#7

Steam Electricity NaturalGas

CoolingWater

WastewaterTreatment Incineration

CompressedAir

TreatedWater

Utilities

$6,647 k/yr55.9%150k MWh$44.4/MWh

$3,487k/yr29.3%590k MBtu$5.91/MBtu

$420k/yr3.5%10,244k kgal$0.041/kgal

$1k/yr0.0%1k SPU$1.20/SPU

$74k/yr0.6%3k klb$23.06/klb

$42k/yr0.4%58k kgal$0.724/kgal

$37k/yr0.3%214k kcf$0.174/kcf

#8$60k/yr0.5%314k kcf$0.174/kcf

$11,900k/yearEC TEX PE-1 Utilities

#9

$1,131 k/yr9.5%205k KESV$5.51/KESV

Nitrogen

CRITICAL COST ISSUES


Structured Brainstorming w/ Stakeholders

Site Participants Include:Site & Mfg. Unit Mgmt. Raw Matls./Interm. Supplier Process Tech. ExpertsPlant Shift Operations Rep.Maintenance SpecialistFinance/Business Rep.

Totals: 6-10 Plant, plus 5-7 Consultant team

Involves Key People on an ‘AS NEEDED’ basis: OnlyOne Week per Mfg. Dept.

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Heat and Material Balance Simulation Models (Process + Utilities)

Essential to get full understanding of where the Raw Materials and Energy goHelps to pin-point areas of opportunitySuggests potential process improvementsServes as design basis for Level 2 Energy Optimization study (process heat recovery as well as CHP system)


Example PFD – bioprocess plant

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Example HMB model – biotech plant


CHP System Simulation Model

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Marginal steam prices - discontinuous

1

1.5

2

2.5

3

3.5

4

4.5

0 25 50 75 100 125 150

Klb/h STEAM GENERATED

Incr

emen

tal S

team

Cos

t, $/

Klb

Target Steam s avings


Operational Improvements

Establishing & following Best Practices w.r.t. operating proceduresSimple process piping/control modificationsReducing Process variabilityOptimum equipment load allocation policiesMonitoring & TargetingProcess Controls (eg. CHP optimizer, MVC)

Energy Cost savings can be achieved at little or no capital costthrough:

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Equipment Efficiency/Capacity Upgrades

PumpsCompressorsMotorsHeat ExchangersFired heaters (furnaces)Boilers (fired and unfired)Steam & Gas TurbinesRefrigeration cycles

Electronic spreadsheet templates are most convenient


Consumption vs Conversion/Transfer

Energy Consumers:PumpsCompressorsFurnaces (fired heaters)Distillation columns

Energy Converters:BoilersTurbinesMotorsGenerators

• Energy Transfer Devices:Heat exchangers

Efficiency definition is different for each type

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Electrical Power Savings, with ASDs

903 MWH/yr

= $24.4 K/yr

ROI = 17.8 %

CONFIDENTIAL


Pinch Analysis tools

Energy targets Composite CurvesUtilities selection GCCOptimum ∆Tmin Range targetingOptimum HEN design (new) Grid diagram, CP matrix and Driving Force PlotOptimum HEN retrofit RPA, etcProcess Mods appropriate placement, +/- principleOptimum CHP design Total Site analysis

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Composite Curves

Qcold

Qhot

Tem

p

Heat Load

Qhot & Qcold are theenergy targets

Pinch Used for Energy

Targeting

Used for Energy

Targeting


T

CoolingWater

Steam

Process HeatTransfer

DO NOT

• use Steam below Pinch

• use CW above Pinch

• transfer heat from process streams above Pinch to process streams below Pinch

The Pinch Principle

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Grand Composite Curve - GCC

T

HREFRIGERATION

COOLING WATER

LP STEAM

HP STEAM

Used for utilities

placement

Used for utilities

placement


Finding the Global Optimum ∆Tmin

Goal is to identify Near-Optimum ∆Tm range

Total Opercost, K$/yr

∆T

Near-Opt range

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Global Economic Optimization

Correct energy pricingAccurate Capital costs, including offsetsRisk-adjusted ROIEnvironmental credits (eg. GHG)Health cost creditsSocial cost credits (eg. disaster relief)Strategic (eg. long-term access to energy sources)


Grid Diagram identifies Pinch + XP ht tr

H1

H2 C

Pinch

176°

158° 158°

C2140° 140°

C1H 140°

∆Tmin = 18°

XP ht tr is in this HX

212°

248° 86°

104°

356°

266°

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Driving Force Plot – HX placement in HEN

Bad Match

Good match


100% conversion of Q W

T

HeatEngine W

Q - W

QA - (Q - W)

A + W

HeatEngine W

Q

B - Q Q - W

No improvement in system η

T

HeatEngine W

Q - W

B + (Q - W)

QA

A + Q

Appropriate Placement - Cogeneration

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Optimum Utilities: Total Site Analysis

Curves are composites of the RESIDUAL heating and cooling duty segments from the GCCs of individual process units

Net processcooling demand= available heat

Net processheatingdemand

T

wHP

Req. Q

Enthalpy, MMBtu/hCW

BFW

LP stm


Magnitude of Savings = f (Payback)

Savings vs Payback

0

20

40

60

80

100

120

0 2 4 6 8 10 12

Simple Payback, yr

% o

f Max

Pot

entia

l

Low

High

If you set unrealistic ROI requirements, you will FAIL

Here

or Here?

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Why use Pinch Analysis?

Systematic procedure can find best flowsheet structure, even (in fact especially) for very complex plantsQuicker + cheaper than traditional approachRigorous energy targets; we know when to quitSaves energy and capital without sacrificing safety, operating flexibility, or reliabilityFor new plant design, there is an optimum time to do it; but mgmt needs to be educated.


Ener

gy C

onsu

mpt

ion

Time

PINCH ENABLESSTEP CHANGEIN EFFICIENCYIMPROVEMENT

The Learning Curve …

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YES

Traditional Project Workflow

Idea

Data Design

Econ-omics

OK?

Build

NO

• Iteration fromEnd point toBeginning

• Lot of work

• Time consuming

• Expensive


Project Workflow for PINCH Approach

Idea

Data TargetsTargets

Design

OK?

Build

YES

NO

• Iteration fromIntermediatePoint toBeginning

• Reduced effort

• Faster

• Cheaper

Econ

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The Pinch Design Strategy

First structural optimization, using Pinch AnalysisThen parametric optimization, using simulation models


Cost Impact vs Project Schedule

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Best Times for PFD Optimization


Typical On-line CHP s/w Architecture

Hydrogen Fuel Steam Water ElectricityUtility Systems

External Utilities Contracts

Emissions Regulations

ProcessIndustrialSite

Real‐Time Optimizer finds the best way to operate all utilities subject to contractual, environmental and operational constraints

OptimumUtilitiesOperationsReport

Measurements

OptimumSet Points

Key Performance IndicatorsMonitoringand AccountingReports

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Case Study – generic BioTech plant

High-value biomass product

Fermentation + evaporation + drying

Design based on scale-up of lab process

8000 hours per yr operation


Simplified PFD

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Base Case Utility Consumption & Costs

What would YOU do to improve process efficiency & economics ?

(includes Dryer steam duty)


Level 1 PEO idea: Btm Cycle Cogen

• Operate Boiler at max design pr (600 psig)

• Add new superheating section (to 700 F)

• Add new Back Pressure Stm Turbexhausting at 175 psig

PRELIM RESULTGood economicsWarrants more study

STBOILER

KW

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Level 2 PEO study: Energy Targets

QH target = 15.2 MMBtu/h, vs 24 MMBtu/h actual use

EVAP OH VAPEVAP DUTY

DRYERVAC JET EXHAUST


Grand Composite Curve partial MVR

CW

175# steam

MVR Vac jet exhaust

Evap duty

Evap OH vapor

Dryer duty

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Revised CCs with right-sized MVR

Vac jet exh Dryer duty

Evaporation duty

MVR disch vapor

Residual EvapOH vapor


PFD for Optimum Process Configuration

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Optimized Utility Costs & Savings

• Minor changes Major opex savings (energy + CO2 + WWT)• New cream separator + recycle improves yield• New fermenter cooling design saved 50% of Rfg (not described)• 60% smaller cogeneration project capital savings• Negligible technical risk; Zero commercial risk• Straight-forward methodology (minimal trial & error)


Summary

Quickly Present and Implement SolutionsUser Friendly Reports

Jump Starts Program, Instant CredibilityCreates Immediate $$ Results

Identifies Most Valuable SolutionsUses Financial & Technical Tools

Saves Time, Maximizes ResultsFocuses on Critical Cost Issues

Doable Solutions, Commit to ImplementInvolves Your Key People

Lowers Unit Cost of Finished ProductIntegrates Process and Energy

BenefitsFeatures

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Benefits of Systematic PEO Approach

Time

Savi

ngs

($)

With PEONPV = 2X W/O PEO

NPV = X

PEO Creates More and Better Solutions.>>> Twice as much implemented in half the time!


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Integrated process optimization

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