Reconciling Mass And Energy Balances In An Ethylene Complex

Reconciling Mass and Energy Reconciling Mass and Energy Balances in an Ethylene ComplexBalances in an Ethylene ComplexReconciling Mass and Energy Reconciling Mass and Energy Balances in an Ethylene ComplexBalances in an Ethylene Complex

Patrick TruesdaleSenior ConsultantIndustry Solution GroupEmerson Process Management

November 11, 2009Nashville, TN

© Emerson Process Management 11-Nov-2009, Slide 2

Presentation ObjectivesPresentation ObjectivesPresentation ObjectivesPresentation Objectives

Background and Business Challenge Business Opportunities How to Achieve? Case Examples Summary


IntroductionIntroductionIntroductionIntroduction Accurate measurements are an essential part

of a refinery or petrochemical complex Measurement technology has dramatically

improved in past 25 years Environmental and governmental regulations

have increased necessitating accurate measurements

Changing demographics Benefits can be significant!


SteamCracker

CondensateSplitter

ACUVDU

FCC

Reformer

Hydrotreating

BTX

DistillateProcessing

GasolineProcessing

Benzene

Toluene

Xylene

Jet, Kero, Diesel

Fuel Oil

Gasoline

Propylene

Ethylene

Propylene

Butadiene

Benzene

Toluene

Feed Stock

Condensate

Crude

Reformate

Aro

mat

icN

aph

tha

Gas

Oil

Pyr

olys

is F

O

FC

C G

as Hyd

roge

n

C6

+ fr

act

ion

C4

raff

ina

te

Jet

Fu

el

Die

sel F

uel

Ethylene Plants: Ethylene Plants: Configuration and ComplexityConfiguration and ComplexityEthylene Plants: Ethylene Plants: Configuration and ComplexityConfiguration and Complexity

Ref: T. Ren, University of Utrecht and BASF 2000


Statistic World NA LA EU/FSU MEA APEthylene Capacity (MM tons/yr) 126.7 35.4 5.1 33.5 19.3 33.4Breakdown (%wt)

Naphtha 55 20 80 75 10 75Ethane/propane/Butane 30 70 20 5 85 5

Other 15 10 0 20 5 20Propylene Capacity (MM tons/yr)Total Process Energy (EJ) 3 0.6 0.2 0.8 0.5 0.9Total CO2 Emission (MM tons/yr) 193 45 7 55 26 60

43% from Cracker/57% from refinery

Ethylene Plants:Ethylene Plants:Estimated Capacities – 1 Jan. 2009Estimated Capacities – 1 Jan. 2009Ethylene Plants:Ethylene Plants:Estimated Capacities – 1 Jan. 2009Estimated Capacities – 1 Jan. 2009

Ref: OGJ 30 July 2009


Ethylene Plants: Ethylene Plants: Global Distribution and AgeGlobal Distribution and AgeEthylene Plants: Ethylene Plants: Global Distribution and AgeGlobal Distribution and Age

PredominantlyGreenfield

PredominantlyBrownfield

In 1980’s Plants were typically ca 300kta

Now Mega Crackers > 1,000kta


Hydrocarbon/Measurement TimelineHydrocarbon/Measurement TimelineHydrocarbon/Measurement TimelineHydrocarbon/Measurement Timeline

1600 1700 1800 1900 1940 1980 2000 Present

347 ADChinaWells

1594 ADBakuWells

Petroleum

1662Boyles Law

1730'sPitot,

BernoulliTechnology

< 4,000 BC“Fountain of Pitch”

1790Woltman

1800'sVenturi

PD MeterCoriolis

1846Gesner(Kero)

1898ASTM

1854Pa. Rock Oil

Co.

1872Barrel = 42

gals.

Economics

Whale Oil$0.40/gal

Kero$0.47/gal

1918AGA1919API

1902NPRA

1940Daniel

Orifice Fitting Co,

1960 1990

1970EP A 2002SO X

1977M MIC ori oli sM ete r

1 9 5 0+ Ele c tr o n ic Er a

2003So nar Met er1963U lt raso nicM ete r 2005Sm ar t Met er

Crude Price Profile (Cushing WTI Spot FOB)

10

30

50

70

90

110

130

150

US

$/B

bl

1859Drake Well

1970EPA

2002SOX

1977MMI

CoriolisMeter

1950+ Electronic Era

2003Sonar Meter

1963Ultrasonic

Meter

2005Smart Meter

19361st Ethylene

Plant1669

Becher


Challenges to achieve benefitsChallenges to achieve benefitsChallenges to achieve benefitsChallenges to achieve benefits

1. Measurement systems for Mass are relatively new for old Plants

2. Belief that errors are mostly due to fuel gas/oil production/consumption over/under statement (ie. Little need to coordinate energy usage with losses)

3. Prices have escalated rapidly in past few years; currently many plants are spending significant capital to met new specs, increase capacity, regulatory compliance, process cheaper feed stocks. Staff is stretched.

4. Business function and organization requires addressing NOT just software tools; but the new operator and engineer in plant.


Typical Plant DemographicsTypical Plant DemographicsTypical Plant DemographicsTypical Plant DemographicsOperations Engineering Maintenance

Small decline dueto automation

Downsized by 70 - 90% Downsized by 5% per year for past 10 years.

0-20 21-34 35-44 45-54 55-65 65+Age

Typical Plant w/ 3,308 workers • Operators now responsible for optimization efforts• 75+% experienced operators slated to retire by 2015• Skilled labor pool falling


Meet the New Engineers and Operators!Meet the New Engineers and Operators!Meet the New Engineers and Operators!Meet the New Engineers and Operators!

We may dress funny but we’re computer geeks!





Key Performance IndexesKey Performance IndexesKey Performance IndexesKey Performance Indexes

Asset Utilization Plant Reliability Operating Efficiency Margin Energy Efficiency Loss Opportunities Environmental Safety


Where are losses? Why Important?Where are losses? Why Important?Where are losses? Why Important?Where are losses? Why Important?

Open Inventory + Receipts – Shipments – Closing Inventory = Gain/Loss

Gain/Loss = Accountable + Unaccountable

Leaks

Theft

FlareCoke

Fuel Produced

Fuel Consume

d


Energy EfficiencyEnergy EfficiencyEnergy EfficiencyEnergy Efficiency


Step 1: Step 1: Define Process BoundariesDefine Process BoundariesStep 1: Step 1: Define Process BoundariesDefine Process Boundaries

C2 Hydrogenation

Cold Box C2 S

plitter

Dep

rop

ani

zer

C3 Hydrogenation

C3 S

plitter

Deb

utan

izer

Deeth

aniz

er

Cracked Gas Compressor

Quench Tower

Cracking Furnaces

Hydrogen 1%-9%

Methane 6%-28% (fuel)

Ethylene 23%-76%

Ethane 3%-20% (recycle)

Propylene 3%-16%

Propane 2%-10%

C4s 2%-9%

Gasoline <1%-35%

Steam & Waste Heat

Steam

SteamFeeds (60%)

Ethane (C2)Propane (C3)Butane (C4)Naphtha (C5 – C12)Gas Oil (C10 – C15)

Fuel Gas

Dem

ethan

izer

Drying and Chilling

Ethylene and Propylene Refrigeration Systems

Steam (40%)

Quench Water Circuit

Oil / Tar Fractionator

Fuel Oil

Tar

800-900 °C1.5 bar

350 °C1.5 bar

30 °C1.5 bar

10 °C1.5 bar -100 °C

32 bar

20 °C5 bar

50 °C2 bar

-10 °C30 bar

10 °C10 bar

-10 °C30 bar

75 °C30 bar

70 °C8 bar

90 °C5 bar

45°C5 bar

45°C16 bar

35°C16 bar

-20 °C20 bar

-30 °C20 bar

-6 °C20 bar

80 °C1.5 bar

FiredHeater

Distillation

CryogenicDistillation

HydrogenationReactor

TurboCompressor


Shore Ship

Consumers

Raw Material Production & Supply Ethylene Complex

Load Port

Logistics

Unload Port

Ship Shore ShoreShip TransportationLoss

Load Port

Transportation LossShore

Unload Port

Ship

BOL

BOL$ “The Cash Register”

Step 2:Step 2:Identify Custody Transfer Boundaries? Identify Custody Transfer Boundaries? Step 2:Step 2:Identify Custody Transfer Boundaries? Identify Custody Transfer Boundaries?


Step 3: Step 3: Design Mass and Energy BalancesDesign Mass and Energy BalancesStep 3: Step 3: Design Mass and Energy BalancesDesign Mass and Energy Balances

ReceiptsReceipts ShipmentsShipments

IntercompanyIntercompany

InventoriesInventories

Tank-to-tank transfers

Tank-to-tank transfers

Unit-to-tank

transfers

Unit-to-tank

transfers

Process Nodes

Process Nodes

Tank-to-unit transfers

Tank-to-unit transfers

LossesLosses Consumption

Consumption


Step 4:Step 4:Survey Measurement SystemsSurvey Measurement SystemsStep 4:Step 4:Survey Measurement SystemsSurvey Measurement Systems

With poor instrumentation and procedures:= 1.5 - 2.5% Mass losses

With average instrumentation and procedures:= 0.7 – 1.5% Mass losses

With good instrumentation and procedures:

= < 0.5% Mass losses

Pacesetter = <0.2%Pacesetter = <0.2% Pacesetter look at Solomon KPI; Others such Shell Global Services, Juran, etc.


Select Technology RequiredSelect Technology RequiredSelect Technology RequiredSelect Technology Required

Pressure Drop Accuracy

LowMaintenance

SlurryFlows

ViscosityIndependent

Flow meterType

Non-ConductiveFluids

Non-Intrusive

Turbine

PositiveDisplacement

Coriolis

Magmeter

DifferentialPressure

Vortex

Good Marginal Poor

Ultrasonic


Coriolis Measurement CapabilitiesCoriolis Measurement CapabilitiesCoriolis Measurement CapabilitiesCoriolis Measurement Capabilities

Direct MASS flow measurement Rangeability: (100:1 non custody), (20:1 custody)

Accuracy (@20:1 turndown)

− Mass Flow Rate: ±0.10 %− Volume Flow Rate: ±0.13%

Unaffected by most fluid variations− P,T,density,viscosity, conductivity− Velocity profile independent

Bi-Directional Multi-variable outputs available

− Qm, Qv, T, Density, % Solids, Viscosity


Tank Gauge Measurement CapabilitiesTank Gauge Measurement CapabilitiesTank Gauge Measurement CapabilitiesTank Gauge Measurement Capabilities

1 API ± 3/16" (4 mm)2 PTB, Germany3 NMi, Netherlands4 OIML, International5 TankRadar


21

Flow meters or ATG’s ?Flow meters or ATG’s ?Flow meters or ATG’s ?Flow meters or ATG’s ?

Influence of batch size:

– At large transfer volumes ATG’s have potential to have better performance. Systematic error on a meter will have a large influence.

– At small transfer volumes meters have potential to have better performance. Resolution may not be sufficient on an ATG.


Do errors always get even out? Do errors always get even out? Think again!Think again!Do errors always get even out? Do errors always get even out? Think again!Think again!

NO: Statistical sum of several measurement errors equals:

Square Root of the sum of Square of the errors

When adding several errors, sum can not be zero!


Step 6:Step 6:Develop Mass & Energy Balance ModelsDevelop Mass & Energy Balance ModelsStep 6:Step 6:Develop Mass & Energy Balance ModelsDevelop Mass & Energy Balance Models

Validation, Detection and Correction: Gross and Bias Errors Reconciles for Random Errors

– Mass and Volume balancing • Flows, inventories, material transfers

– Component balancing (Simple and Multi-phase)• Flows, inventories

– Energy balancing• Enthalpy, power, heat exchanger balance, steam

– Simultaneous Solution of all equations


Example Heat Balance EnvelopeExample Heat Balance EnvelopeExample Heat Balance EnvelopeExample Heat Balance Envelope

100 Kg9.242 MJ91423.7 J/Kg

100 Kg1.068 MJ10683.6 J/Kg

100 Kg4.217 MJ42170 J/Kg

100 Kg12.291 MJ122.9 KJ/Kg

100 Kg3.871 MJ38706 J/Kg

100 Kg11.944 MJ11944.6 J/Kg

Flow Measurement Tolerance Reconciled Value MT1 10 kg 1.5 kg 10.3 kg

T1 HT1 42174 J/kg 843.5 J/kg 42237 J/kg

T2 MT2 11 kg 5.5 kg 10.3 kg

HT2 31631 J/kg 3163.1 J/kg 30724 J/kg

MS1 12 kg 1 kg 11.64 kg S1

HS1 21087 J/kg 1054.4 J/kg 21203 J/kg

MS2 11 kg 1.55 kg 11.64 kg S2

HS2 31631 J/kg 1581.5 J/kg 31356 J/kg


Example Heat Balance EnvelopeExample Heat Balance EnvelopeExample Heat Balance EnvelopeExample Heat Balance Envelope

100 Kg9.242 MJ91423.7 J/Kg

100 Kg1.068 MJ10683.6 J/Kg

100 Kg4.217 MJ42170 J/Kg

100 Kg12.291 MJ122.9 KJ/Kg

100 Kg3.871 MJ38706 J/Kg

100 Kg11.944 MJ11944.6 J/Kg

Flow Measurement Tolerance Reconciled Value MT1 10 kg 1.5 kg 10.3 kg

T1 HT1 42174 J/kg 843.5 J/kg 42237 J/kg

T2 MT2 11 kg 5.5 kg 10.3 kg

HT2 31631 J/kg 3163.1 J/kg 30724 J/kg

MS1 12 kg 1 kg 11.64 kg S1

HS1 21087 J/kg 1054.4 J/kg 21203 J/kg

MS2 11 kg 1.55 kg 11.64 kg S2

HS2 31631 J/kg 1581.5 J/kg 31356 J/kg


Step 5:Step 5:Define Business ProcessDefine Business ProcessStep 5:Step 5:Define Business ProcessDefine Business Process

Period EndCutoff Data

Period EndCutoff Data

Gross Error Detectionand Diagnostics

Gross Error Detectionand Diagnostics

TrialBalancing

TrialBalancing

Resolution orReconciliation

Resolution orReconciliation CheckingChecking

ModificationsAdjustments

ModificationsAdjustments

ComplexConfiguration

Models

ComplexConfiguration

Models

MeasurementsMovements

Lab DataMeter Tickets

Surveyor Documents Tank Inventories

Utilities

MeasurementsMovements

Lab DataMeter Tickets

Surveyor Documents Tank Inventories

Utilities

ResultsGeneration

ResultsGeneration

ManualInput

Automatic DataCollection

Reconciled Balances, Yield, Loss and Inventory

Reporting

Reconciled Balances, Yield, Loss and Inventory

Reporting

Production Management

Data Base

Production Management

Data Base

Integrate withOther Systems

(SCM, SAP, LP, etc)

Integrate withOther Systems

(SCM, SAP, LP, etc)


Gross Margin versus Weight Loss

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Month

Wt

% W

eig

ht

Lo

ss

0

50

100

150

200

250

Gro

ss

Ma

rgin

in k

$

Weight Loss Gross Margin

Step 7:Step 7:Identify KPI ReportingIdentify KPI ReportingStep 7:Step 7:Identify KPI ReportingIdentify KPI Reporting


KPI DashboardKPI DashboardKPI DashboardKPI Dashboard


What went wrong??

What went right??

Step 8:Step 8:Implement Continuous ImprovementImplement Continuous ImprovementStep 8:Step 8:Implement Continuous ImprovementImplement Continuous ImprovementWhere did it happen?• Models• Process• Data Quality

Time (Weeks)

• Capacity

• Utilization

• Production rate

• Quality

• Energy

• Yield

• Margin

• Reliability

• Environmental

Before(Monthly)

Plan/Schedule

1 2 3 4 5 6 7 8 9 10 11 12 13 14

ActualOperation

After(Daily)


Get Benefits:Get Benefits:Operational Excellence ImpactOperational Excellence ImpactGet Benefits:Get Benefits:Operational Excellence ImpactOperational Excellence Impact

Up to 7.9% OperationalImprovement by Impacting…

+3% +2.4%

-1.3% -1% -0.2%


Measurement Losses:Measurement Losses:What is it worth?What is it worth?Measurement Losses:Measurement Losses:What is it worth?What is it worth?

93%

1150$/t

500$/t

Assume 0.2% Loss Reduction


Measurement Losses:Measurement Losses:What is it worth?What is it worth?Measurement Losses:Measurement Losses:What is it worth?What is it worth?

Assume 0.2% Loss Reduction

•Product •Capacity •Price •Margin •Utilization factor •Amount•Ethylene •900 kMT/yr •1 150 $/t •500 $/t •93% •47 774 $/hr•Propylene •450 kMT/yr •1 150 $/t •500 $/t •93% •23 887 $/hr

•$71 661•0.2% •$143/hr•1 hr

•1 yr •$1 255 500


Range

• Custody transfer (receipt and shipments)

• Fuel and H2 consumption (understated, not real losses)

• Flare, in effluent, evaporation, stack loss, vents and leaks, coke

0.35 to 0.55

0.85 to 1.05

0.45 to 0.65

TOTAL 1.65 to 2.25

Case 1: Case 1: Losses Analysis (%Mass)Losses Analysis (%Mass)Case 1: Case 1: Losses Analysis (%Mass)Losses Analysis (%Mass)

Estimate

0.45

0.95

0.55

1.95


Case 1: Case 1: Benefit CalculationBenefit CalculationCase 1: Case 1: Benefit CalculationBenefit Calculation Estimate loss = 1.95%

– Custody Transfer Loss = 0.45%

– Flare, Coke, Other Loss = 0.55%

– Apparent (understated fuel/H2 consumption) = 0.95% Improvement

– Achievable Goal = 0.4%• Delta = (0.45%+0.55%-0.4% = 0.6%)

• 0.6% x 12MM T/yr x 210US$/T = $15,120,000/yr

Supply chain optimization– 0.25 $/T x 12MM T/yr = $3,000,000/yr


Case 2: Case 2: Measurement Errors vs Economic LossesMeasurement Errors vs Economic LossesCase 2: Case 2: Measurement Errors vs Economic LossesMeasurement Errors vs Economic Losses

Operating Region

Control Variable

Ob

ject

ive

Fu

nct

ion

(e.

g.

Pro

fit)

Deviations are often corrected with high-cost sub-optimum

correction!

Potential lost profit from inaccurate measurements.


Trading BenefitsTrading BenefitsTrading BenefitsTrading Benefits

A Gulf Coast refiner switched a cargo of crude with justone-and-a-half hours of supply left in inventory.

Without very close coordination between trading and operations,the $8 million profit opportunity would have been lost.

Hydrocarbon Processing


Trading ExampleTrading ExampleTrading ExampleTrading Example

Trader

Gulf Coast Complex

Okay, if you can agree with the shipper to deliver 8 hours earlier, then we will have a four hour safety margin and the trade is agreed.

Hold on while we check:: - Current inventory - Maintenance Plan - Agreed Receipts and Shipmentsand rerun the schedule to check the impact on stocks and cash flow.

Delivery 8 hours earlier is agreed. We make $3,000,000 and we extend our credit line by 3 days. GREAT, is there anything I can do to help with a backup strategy?

We have an excellent opportunity to purchase a cargo of feed stock. Can we take it?


Key TakeawaysKey TakeawaysKey TakeawaysKey Takeaways Ethylene plants have large incentives to reduce losses and

optimize energy usage. These two KPI are interrelated. With the sharp increase in feedstock prices and accessibility, the

industry has a compelling need for improving the timeliness and accuracy of production data.

Specifications and governmental regulations continue to tighten - accurate measurements are essential to mitigate compliance

Since late 1950 there has been and continues to be significant technological improvement in measurement systems

Smart Instruments and Wireless technology opens additional benefits for the future!

Improved accuracy of Production Data (Mass and Energy Balance Reconciliation) impacts many KPI’s . The solution approach, therefore, “is Greenis Green” (provides significant benefits).


Wrap-upWrap-upWrap-upWrap-up

Questions? Comments?

Where to get more information?– White Papers

– Presentations

– Specific requirements?

– Contact: Patrick Truesdale ([email protected])


Thank You

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