energy intensity and key indicators -- industrial energy...
TRANSCRIPT
Energy Intensity and Key Indicators -- Industrial Energy Optimization
© 2014 UOP LLC. All rights reserved.
Texas Energy Management Forum Houston, May 1, 2014
Frank Zhu
UOP LLC, A Honeywell Company
UOP 6017-1
What does “Energy Optimization” Mean?
Minimum energy understates the goal – “minimum” not always best
Energy is an enabler - more energy often translates to greater capacity, better yield, and better products
Overall process impact must be included in the economic evaluation (NPV, ROI, etc) of energy projects
Diesel
Kerosene Fuel Oil
Naphtha
Gasoline
Jet Fuel LPG
UOP 6017-3
Energy Use is a Function of Feed Rate and Yield
UOP 6017-3
How to assess energy efficiency for production variations?
Which operation point,
A or B is more energy efficient?
A
B
Process Energy Intensity
UOP 6017-4
RateoductorFeed
InputEnergyNetIntensityEnergy
Pr
Let me use an example
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Process Unit
Exothermic Reaction
Electricity 3.15 MW
HP steam 157.1 klb/h
Fuel 334.8 MMBtu/h
MP steam export 50 klb/h
Furnace stack loss 89 MMBtu/h
Water cooling duty 126.6 MMBtu/h
Shaft work loss 17.9 MMBtu/h
Surface condenser duty 97.8 MMBtu/h
Condensate loss 10 klb/h
Feed 37kBPD @186 F
BFW 16.5 klb/h @250 F
Condensate return 113.6 klb/h
Energy Input Energy Output
Air cooling duty 299.5 MMBtu/h
How to evaluate all energy usages on the same basis?
Fuel Equivalent Concept
UOP 6017-6
• Steam use/gen are converted to fuel fired Btu/lb steam
• Power import is converted to fuel fired Btu/kWe
• Convert power losses to fuel fired Btu/kWe
• Convert condensate losses to fuel fired Btu/lb, etc
─ All Energy Converted to Fuel Fired at the Source
Process Energy Balance based on FE
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LossEnergy ExportEnergy Reaction of Heatply Energy Sup
Condensate return 10.7 MMBtu/h
Process Unit
Exothermic Reaction
∆Hreaction = 163.4 MMBtu/hFuel 334.8 MMBtu/h
MP steam export 65.5 MMBtu/h
Furnace stack loss 88.9 MMBtu/h
Air cooling losses 352.4 MMBtu/h
Surface condenser 97.8 MMBtu/h
Feed 17.2 MMBtu/h
Other losses 8.3 MMBtu/h
Energy OutputEnergy Generation
Electricity 28.6 MMBtu/h
HP steam 243.5 MMBtu/h
Boiler feed water 2.9 MMBtu/h
Power generation loss 17.9 MMBtu/h
Energy Input
Water cooling losses 148.9 MMBtu/h
Energy export = 65.5+10.7
= 76.2 MMBtu/h
Gross energy input
= 790.4 MMBtu/h
Process Energy Intensity
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RateoductorFeed
InputEnergyNetIntensityEnergy
Pr
bbl kBtu/ 463.2day37,000bbl/
MMBtu/h714.2IntensityEnergy
714.276.2- 790.4ExportEnergy -InputEnergy InputEnergy Net
Energy Performance Index (EPI)
UOP 6017-9
• For operation monitoring, use the best-in-operation as GEI
• For comparison with peers, use the best peers’ performance
• For design assessment, use the state-art-design
GEI
AEI
IntensityEnergy Guideline
IntensityEnergy Actual EPI
Time
En
erg
y I
nte
nsit
y
(MM
Btu
/Ba
rrel F
eed)
Gap
Current performance
Guideline performance
Energy intensity indicates the energy gap
But what about root causes?
GEI is a function of feeds and products
Time
Actual
En
erg
y I
nte
ns
ity
Determine Gaps to Focus Efforts
The energy gaps help to determine areas for focus
The KEI can help identifying real
opportunities with quick payout
for reducing energy costs while
maintaining or even improving
throughput and yields
The Concept of Key Energy Indicators
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10-90 Rules: KI’s Capture Major Process Performance
• Fractionator column reflux ratio
• Fractionator column overflash
• Fractionator flash zone pressure
• Fractionator stripping steam rate
• Heater inlet temperature
• Heater stack temperature
• Heat flux
A process can be described by a small number of parameters
An example of key indicators for a distillation column:
:
The Operating Window for Fractionation Column
UOP 6017-14
Liquid Rate GPM
Vap
or
Rate
CF
S
Feasible Operation Region
Dumping Point
Constant L/V
A
B
Excessive Weeping
KI’s optimize the column operation
UOP 4856G-11
KIs Targets determine opportunities-- An example
Tracking Key Indicators (KI)
– KIs are process parameters, which have significant impact on the overall process yields and energy usage
– Limits and targets for KIs
– Relationship between Kis
– Provide guidance on possible remedial actions
Time
Improved Profit by Changing
Target
Better Control, Reduced Variability Poor Control
Specification Limit
Operating Targets
Pro
du
ct
Co
mp
osit
ion
($
/day P
rofi
t)
KIs helps to Achieve Optimal Operation
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Time
En
erg
y I
nte
nsit
y
(MM
Btu
/Feed
)
Improved performance
Current performance
Guideline performance
Operating Targets
Opportunities for Energy Savings
Opportunities for Energy Savings (typical refinery)
Basis: for a 100,000 BPSD refinery; natural gas cost @ $6/MMbtu
Conclusions
Use of energy intensity is an effective way to assess performance gaps
Key indicators are the enabler for reducing operating costs
Solutions from operational improvements to a wide variety of technology solutions
Energy savings of 12-25% are possible
For details, please see “Energy and Process Optimization for the Process Industries”, by Frank Zhu, Wiley, 2013