Driving Toward Energy EfficiencyDriving Toward Energy Efficiency
Emerson Process ManagementNovaspect. Inc.
June 22 / 23, 2010
SteamSteam
Steam – Take a System ApproachSteam – Take a System ApproachSteam – Take a System ApproachSteam – Take a System Approach
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping
TopicsTopicsTopicsTopics
Insulation
Pressure Reduction
Flash Recovery / Cascade Systems
Steam Trapping & Steam Trap Management
Steam Leak Detection & Repair
Air Venting
Steam Using Process Equipment
Steam Tracing
Atmospheric Flash Tanks / Flash Condensing
Condensate Return
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping
NoteNoteNoteNote
•Today’s presentation is efficiency centric.
•Historically, projects have not been driven solely on energy savings.
•Other drivers include:
-Safety
-Throughput
-Reliability / Maintenance
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping
What Do You Want to Know & Why What Do You Want to Know & Why (Monitoring Points / Value)(Monitoring Points / Value)What Do You Want to Know & Why What Do You Want to Know & Why (Monitoring Points / Value)(Monitoring Points / Value)
•You can’t manage or control what you don’t measure
-Typically steam systems are under measured
•Typical measurement points serve to determine where the steam goes, how much is being used, determine where losses are occurring and to help troubleshoot system issues.
-In steam using process equipment, temperature and ΔP measurements lead to informed process and efficiency improvement decisions.
-In the distribution / condensate return system the ΔP is the condensate driver; flow and temperature measurement let you monitor and put a value to the energy being returned back to the boiler.
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping
Assumptions / ClarificationsAssumptions / ClarificationsAssumptions / ClarificationsAssumptions / Clarifications
100 PSIG Steam Cost / Per 1K LB 8.89Inlet Temperature / °F 40.00Fuel / Nat. Gas 4.82Water 0.64Chemical Treatment 0.05Sewer 0.38Facilities / Infrastructure / Personnel 3.00
H2O 8.35 LB/GALH2O 7.34 GAL/FT3H2O $ 0.03926 FT3H2O Sewage $ 0.0236 FT3H2O $ 0.005348774 GALH2O Sewage $ 0.00315508 GALH2O $ 0.000640572 LBH2O Sewage $ 0.000377854 LBNat. Gas $ 0.00000408 BTUChemical Trtmt $ 0.00005 LB/STM
•Cost of Steam
•Definitions
-Sensible Heat: Btu’s contained in liquid-Latent Heat: Btu’s gained at vaporization and given up at condensation-Superheat: Btu’s over and above those gained at the at vaporization – generally measured as temperature above that of saturated steam
Cost Savings through Steam Efficiency Cost Savings through Steam Efficiency Cost Savings through Steam Efficiency Cost Savings through Steam Efficiency
Gallons Wash-down Water / Day 1,000,000.00Pounds Wash-down Water / Day 8,350,000.00Wash-down Water Inlet Temperature / °F 40.00Wash-down Water Outlet Temperature / °F 150.00
Properties of 100 PSIG Steam Latent Heat of Steam / BTU per LB 880.70Cost Per 1K LB 8.89
100 PSIG Steam Load Requirement at 100% Efficiency / LB 1,042,915.67Cost to Heat 1,000,000 Gallons of Wash-down Water / Day 9,271.39$ Cost to Heat Wash-down Water / Year 3,384,057.65$
Low Quality / % Entrained Water or Air 5%Low Quality / Latent Heat of Steam / BTU per LB 836.67100 PSIG Steam Load Requirement at Reduced Efficiency / LB 1,097,805.97Cost to Heat 1,000,000 Gallons of Wash-down Water / Day 9,759.36$ Cost to Heat Wash-down Water / Year 3,562,165.95$
Cost for 5% Efficiency Loss 178,108.30$
InsulationInsulationInsulationInsulation
Prevention of radiant heat loss (condensing of steam)
100 PSIG Steam, 100’ 8”, Schedule 40 Pipe, 10 MPH Wind Speed, 40°F
•Uninsulated Pipe
-415 PPH Condensate / 365,700.9 Btu/HR
-$32,337 Annual Cost
•Insulated Pipe (2” Calcium Silicate)
-19.1 PPH Condensate / 17,097.4 Btu/HR
-$1,512 Annual Cost / $30,825 Annual Savings
-Approximate Payback = 36 days based an installed insulation cost of $3,000; 71 days based an
installed insulation cost of $6,000
InsulationInsulationInsulationInsulation
Prevention of radiant heat loss (condensing of steam)
100 PSIG Steam, 100’ 8”, Schedule 40 Pipe, 0 MPH Wind Speed, 70°F
•Uninsulated Pipe
-206 PPH Condensate / 181,654 Btu/HR
-$16,063 Annual Cost
•Insulated Pipe (2” Calcium Silicate)
-19.8 PPH Condensate / 17,426 BTU
-$1,541 Annual Cost / $14,522 Annual Savings
-Approximate Payback = 75 days based an installed insulation cost of $3,000; 151 days based an
installed insulation cost of $6,000
Pressure ReductionPressure ReductionPressure ReductionPressure Reduction
Ideally, you would produce steam at the pressure you need at the location it’s required in the quantity needed…•Higher pressure generation
-Smaller Pipe Diameter-Superheated Steam -Need for pressure reduction
•Do work during the reduction process-Generate electricity, compress air
•Elimination of superheat (process fouling)-Latent heat transfer
Flash Recovery / Cascade SystemsFlash Recovery / Cascade SystemsFlash Recovery / Cascade SystemsFlash Recovery / Cascade Systems•Condensate from higher pressure system sent to steam trap(s).
•Traps discharge into a vessel that is regulated at a pressure slightly above the lower pressure steam system.
•The portion of the condensate that “flashes” into steam is recovered into the lower pressure system.
•Lower pressure system requirements not met by the flash recovery / cascade system are supplied through supplemental let down and / or lower pressure steam production.
•This allows for multiple uses of each pound of generated steam
Flash Recovery / Cascade SystemsFlash Recovery / Cascade SystemsFlash Recovery / Cascade SystemsFlash Recovery / Cascade Systems
ValueLoad / PPH
Primary Pressure
Secondary Pressure
% of Flash Steam
PPH Flash Steam
Steam Cost
Hourly Savings Annual Savings
100,000 100 50 4.58% 4577.4 $ 8.89 $ 40.69 $ 356,471.43 100,000 50 20 4.24% 4239.5 $ 8.89 $ 37.69 $ 330,157.00
100,000 600 150 15.89% 15885.9 $ 8.89 $ 141.23 $ 1,237,136.70 100,000 150 15 16.33% 16329.9 $ 8.89 $ 145.17 $ 1,271,713.82
Steam TrappingSteam TrappingSteam TrappingSteam Trapping
Where:
-Every 100-150’, before rise, after fall, before control valve, at end of line, at steam using process equipment as appropriate.
Why:
-Condensate removal / maximum Btu latent heat per pound of steam
-Reliability (hydraulic shock, cutting valves / components)
-System Start Up
Steam Trapping – Trap EfficiencySteam Trapping – Trap EfficiencySteam Trapping – Trap EfficiencySteam Trapping – Trap Efficiency
Steam Use/HR $/1K Annual $ Population Total $ Difference
0.30
$8.89
$ 23.36
1000
$ 23,363 -
1.72 $ 133.95 $ 133,947 $ 110,584
2.53 $ 197.03 $ 197,027 $ 173,664
2.60 $ 202.48 $ 202,479 $ 179,116
3.38 $ 263.22 $ 263,222 $ 239,859
3.52 $ 274.12 $ 274,125 $ 250,762
4.14 $ 322.41 $ 322,408 $ 299,045
4.77 $ 371.47 $ 371,470 $ 348,108
Steam Trap ManagementSteam Trap ManagementSteam Trap ManagementSteam Trap Management
Total Trap Population 100.0% -Good 59.8% -Blocked 4.7% -Low Temperature 4.9% -Blowing 2.4% 1,835.19$ Leaking 11.1% 495.52$ Not in Service 16.7% -Other 0.4% -
Steam Leak Detection & RepairSteam Leak Detection & RepairSteam Leak Detection & RepairSteam Leak Detection & Repair
Hole Diameter x .7 Disch Coeff
PPH Steam Loss $/1K LBS Annual Loss
1 4411.1 8.89$ 343,520.59$ 7/8 3377.3 8.89$ 263,011.97$ 3/4 2481.3 8.89$ 193,234.71$ 5/8 1723.1 8.89$ 134,188.82$ 1/2 1102.8 8.89$ 85,882.09$ 3/8 620.3 8.89$ 48,306.73$ 1/4 275.7 8.89$ 21,470.52$ 1/8 68.9 8.89$ 5,365.68$ 1/16 17.2 8.89$ 1,339.47$ 1/32 4.3 8.89$ 334.87$
100 PSIG Steam / 100 PSID
Air VentingAir VentingAir VentingAir Venting
Removal of entrained air or inert gasses.
- Insulator / inefficient heat transfer medium
- % by volume leads to reduced BTU availability
Tell-tale
-Temperature reduction
Secondary Benefits
-Reduction of probability of hydraulic shock
-Reduction of temperature stratification (process)
Steam Using Process EquipmentSteam Using Process EquipmentSteam Using Process EquipmentSteam Using Process Equipment
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Separation-Steam Quality-Efficiency
•Use the lowest pressure that will meet the process needs.
PressureSaturation
TemperatureSensible
Heat Latent Heat Total Heat0 212 180 970 1150
15 250 218 946 116450 298 267 912 1179
100 338 309 880 1189150 366 339 857 1196300 422 399 805 1204600 489 475 728 1203900 534 529 667 1196
1500 598 614 556 11702100 644 685 444 1129
Steam Using Process EquipmentSteam Using Process EquipmentSteam Using Process EquipmentSteam Using Process Equipment
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Separation-Steam Quality-Efficiency
•Use of saturated steam for process heat exchange.
•50°F of superheat results in an additional 29 Btu per LB, or .58 Btu per degree of temperature.•The process has to shed temperature (at .58 Btu per degree) before it gets to the point of latent heat transfer by condensing at saturation temperature.
Properties of 100 PSIG Steam Saturated Steam Temperature / °F 337.9Latent Heat of Steam / Btu per LB 880.704Specific Enthalpy of Saturated Steam / Btu per LB 1189.728Specific Enthalpy of Saturated Water / Btu per LB 309.024
Superheated Steam Temperature / °F (+50°F) 387.9Latent Heat of Steam / Btu per LB 880.704Specific Enthalpy of Superheated Steam / Btu per LB 1218.616Specific Enthalpy of Saturated Water / Btu per LB 309.024
Steam Using Process EquipmentSteam Using Process EquipmentSteam Using Process EquipmentSteam Using Process Equipment
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Separation-Steam Quality-Efficiency
•Complete condensate drainage of heat exchange equipment
-Steam Trap
-Other condensate drainage method
Steam TracingSteam TracingSteam TracingSteam Tracing Med. Pressure Tracing Low Pressure Tracing
•Seasonal isolation of manifolds.
-Automated drainage scheme
•Installation best practices to ensure maximum heat transfer.
-Insulated, heat transfer cement, no air gaps
•Pay attention to ΔP across traps.
-Follow maximum tracing run guidelines
•Sensible heat for low demand / non-critical tracing.
-Instrument & instrument enclosures
•Segment Tracing Application Specifications Based on Criticality.
Atmospheric Flash Tanks / Flash CondensingAtmospheric Flash Tanks / Flash CondensingAtmospheric Flash Tanks / Flash CondensingAtmospheric Flash Tanks / Flash Condensing
•Every Btu counts
-“Waste Heat” vs. pre-heat of BFW, freeze protection
-Reduced flash venting
-More warm condensate returned for reuse
•Wrapped tubing, pipe in pipe heat exchanger, plate & frame HX
Condensate RecoveryCondensate RecoveryCondensate RecoveryCondensate Recovery
Rule of Thumb Best Practice:
• Minimum 7 turns of BFW, 13% Make-up
• Recovery of water, treatment costs, sensible heat value coupled with cost avoidance (sewage / treatment).
How
• ΔP as motive
• Local vented receiver with electric or secondary motive pressure pumps
Condensate Recovery - ValueCondensate Recovery - ValueCondensate Recovery - ValueCondensate Recovery - Value
PPH Steam Produced 500,000.00 500,000.00 500,000.00Pressure 100.00 100.00 100.00Temperature 337.90 337.90 337.90Btu/LB Sensible 309.02 309.02 309.02Btu/LB Latent 880.70 880.70 880.70Inlet H2O Temperature 40.00 100.00 190.00H2O Btu/LB Sensible 8.00 68.00 158.00
Additional Sensible Required, Btu/LB 301.02 241.02 151.02Additional Required x PPH 150,512,000.00 120,512,000.00 75,512,000.00Cost / MM Btu 4.82 4.82 4.82Additional Costs (H2O, Treatment,…) 1.07 1.07 1.07Cost 886.52$ 709.82$ 444.77$
Savings / HR -$ 176.70$ 441.75$ Savings / Year -$ 1,547,892.00$ 3,869,730.00$
Condensate Recovery - ValueCondensate Recovery - ValueCondensate Recovery - ValueCondensate Recovery - Value
Steam Value / Per 1K LB 8.89Condensate Value / Per 1K LB
BTU Value (172 Btu/LB) 0.83Water 0.64Chemical Treatment (Initial x .5) 0.03Sewer 0.38Total (without F / I / P) 1.87 21%
Next StepsNext StepsNext StepsNext StepsTake Action on Previously Identified Opportunities
Steam System Audit
-Leak Survey
-Insulation Survey
-Information “White Space”
Process Audit
Steam Trap Survey
Identify Low Hanging Fruit
Identify Costs / Losses / ROI
Prioritize
Act
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping
QuestionsQuestionsQuestionsQuestions
Air Venting
Steam Generation
Insulation
Steam Traps Distribution Drain Traps
High Pressure Process Use
Med. Pressure Process Use
Low Pressure Process Use
Pressure Let Down
Flash Recovery / Cascade Systems
Atmospheric Flash Tank for Condensate Recovery
Make Up Water
Med. Pressure Tracing
Low Pressure Tracing
Condensate Pumping
Separation-Steam Quality-Efficiency
Local Atmospheric Flash Tank for Condensate Recovery w/Condensate Pumping