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Convert Gas Pneumatic Controls to Convert Gas Pneumatic Controls to Instrument AirInstrument Air
Lessons LearnedLessons Learned
from Natural Gas STAR Partnersfrom Natural Gas STAR Partners
EPA’s Natural Gas STAR Program,EPA’s Natural Gas STAR Program,
Pioneer Natural Resources USA, Inc., andPioneer Natural Resources USA, Inc., and
The Gas Processors AssociationThe Gas Processors Association
June 17, 2003June 17, 2003
Page 2Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Air Pneumatic DevicesAir Pneumatic Devices
Methane LossesMethane Losses Methane Recovery Methane Recovery Is Recovery Profitable?Is Recovery Profitable? Spreadsheet-based Analytical ToolsSpreadsheet-based Analytical Tools Industry ExperienceIndustry Experience Discussion QuestionsDiscussion Questions
Page 3Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Natural Gas Pneumatic SystemNatural Gas Pneumatic System
Gas Out
Pressure Controller
Natural Gas from Plant
Inlet Fluids
Liquid Out
Utility Services
Instrumentation and Control Systems Piping Network
20-30 PSI Network
LLC
LLC: Liquid Level Controller
Page 4Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Sources of Methane LossesSources of Methane Losses
As part of normal operations, pneumatic As part of normal operations, pneumatic devices release natural gas into the devices release natural gas into the atmosphereatmosphere
High-bleed devices bleed in excess of 6 scf High-bleed devices bleed in excess of 6 scf per hourper hour Equates to >50 Mcf/ yearEquates to >50 Mcf/ year Typical high-bleed pneumatic devices bleed an Typical high-bleed pneumatic devices bleed an
average of 140 Mcf/yearaverage of 140 Mcf/year
Page 5Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Magnitude of Methane LossesMagnitude of Methane Losses
Major source of methane losses from the Major source of methane losses from the natural gas industrynatural gas industry
Pneumatic devices are used throughout the Pneumatic devices are used throughout the natural gas industrynatural gas industry Over 13,000 in the processing sectorOver 13,000 in the processing sector Estimated methane loss of 16 Bcf/year = $48 Estimated methane loss of 16 Bcf/year = $48
million! million!
Page 6Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Convert to Instrument Air devicesConvert to Instrument Air devices
Most applicable to:Most applicable to: Large facility with high bleed pneumatic devices and Large facility with high bleed pneumatic devices and
has access to electricityhas access to electricity Major components of instrument air systemMajor components of instrument air system
CompressorCompressor Power SourcePower Source Air DrierAir Drier Volume TankVolume Tank
Page 7Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Compressed Instrument Air SystemCompressed Instrument Air System
Gas Out
Pressure Controller
Air from Atmosphere
Inlet Fluids
Liquid Out
Utility Services
Instrumentation and Control Systems Piping Network
20-30 PSI Network
LLC
LLC: Liquid Level Controller
Air Drier
Compressor Volume Tank
Page 8Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Instrument Air Decision ProcessInstrument Air Decision Process
Identify possible locations Identify possible locations for system installationsfor system installations
Estimate project costsEstimate project costs
Determine optimal system capacityDetermine optimal system capacity
Estimate gas savingsEstimate gas savings
Evaluate economicsEvaluate economics
Develop an implementation planDevelop an implementation plan
Page 9Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Determine Optimal System CapacityDetermine Optimal System Capacity
Instrument Air RequirementsInstrument Air Requirements Volume of the compressed airVolume of the compressed air
Meter pneumatic gas supply Meter pneumatic gas supply Rule of Thumb: 1 cfm air/control loopRule of Thumb: 1 cfm air/control loop
Adjust for air lossesAdjust for air losses 17% of air input is bypassed in drier17% of air input is bypassed in drier
Utility Air RequirementsUtility Air Requirements Rule of Thumb for pneumatic air systems: Rule of Thumb for pneumatic air systems:
1/3 for instrument air1/3 for instrument air 2/3 for utility air2/3 for utility air
Page 10Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Calculate Gas SavingsCalculate Gas Savings
Determine the Gas Value SavedDetermine the Gas Value Saved Value of Gas = (IAValue of Gas = (IAu u + UA+ UAuu) * M * P/1000) * M * P/1000
IAIAuu= Instrument Air Use: e.g. 35 control loops= Instrument Air Use: e.g. 35 control loops UAUAuu= Utility Air Use: e.g. assume 10 cfm utility gas= Utility Air Use: e.g. assume 10 cfm utility gas M = Minutes in a year (525,600)M = Minutes in a year (525,600) P = Price of Gas: assume $3.00/Mcf P = Price of Gas: assume $3.00/Mcf
Value of Gas = (35*1Value of Gas = (35*1 + 10) * 525,600 * 3.00 / 1,000+ 10) * 525,600 * 3.00 / 1,000 Value of Gas Saved = $ 71,000/yearValue of Gas Saved = $ 71,000/year
Page 11Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Calculate Compressor SizeCalculate Compressor Size
Determine Air Compressor CapacityDetermine Air Compressor Capacity Air Compressor Capacity = IAAir Compressor Capacity = IAS S + UA+ UASS
IAIAS S = = Instrument Air SupplyInstrument Air Supply
== IAIAUU / (100% - % air bypassed in / (100% - % air bypassed in
drier) drier) UAUAS S = = Utility Air SupplyUtility Air Supply
= IAIAU U * (fraction of utility air use) / (fraction of * (fraction of utility air use) / (fraction of
instrument air use)instrument air use)
Air Compressor Capacity Air Compressor Capacity = [(35 /(100% - 17%)) +((35*(2/3))/(1/3))] = 112 cfm= [(35 /(100% - 17%)) +((35*(2/3))/(1/3))] = 112 cfm
Page 12Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Determine Compressor CostsDetermine Compressor Costs
Air Volume
Equipment Costs
Annual Service
Service Life
(cfm) ($) ($/yr) (yrs)
Small 30 Reciprocating 10 2,500 1 300 1
Medium 125 Screw 30 12,500 600 5-6 2
Large 350 Screw 75 22,000 600 5-6 2
1 Cost included package compressor w ith a volume tank.2 Rebuilt compressor costs $3,000 plus $500 labor minus $500 core exchange credit.
Service Size
Compressor Type
Horsepower
Page 13Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Determine Cost of TankDetermine Cost of Tank
Service SizeAir Volume
(gallons)Equipment Cost
($)
Small 80 500
Medium 400 1,500
Large 1,000 3,000
Small reciprocating air compressors, 10 horsepow er and less, are commonly supplied w ith a volume tank.
Page 14Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Determine Cost of DrierDetermine Cost of Drier
Air Volume Equipment Cost
(cfm) ($)
Small 30 membrane 1,500 500
Medium 60 1 membrane 4,500 2,000
Large 350 alumina 10,000 3,000
1 Largest membrane size; use multiple units larger volumes.
Service Size Drier TypeAnnual
Service ($/yr)
Page 15Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Calculate Capital and Operating CostsCalculate Capital and Operating Costs
Determine Capital CostDetermine Capital Cost Equipment Cost = Equipment Cost =
Compressors Cost (2)+Tank Cost (2)+Dryer CostCompressors Cost (2)+Tank Cost (2)+Dryer Cost
= 2*$12,500 + 2*$500 + 1*$4,500= 2*$12,500 + 2*$500 + 1*$4,500 Equipment Cost * Installation Cost FactorEquipment Cost * Installation Cost Factor
Total Capital Cost = $30,500*1.5 = $45,750Total Capital Cost = $30,500*1.5 = $45,750 Determine Operating CostDetermine Operating Cost
Electrical Power = $13,140Electrical Power = $13,140 Engine Power * Operating Factor * Electricity CostEngine Power * Operating Factor * Electricity Cost
Page 16Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Economics of ReplacementEconomics of Replacement
1 1 Electrical Power at 7.5 cents/ kWh.Electrical Power at 7.5 cents/ kWh.22 Maintenance costs include $1,200 compressor service and $2,000 air drier membrane replacement Maintenance costs include $1,200 compressor service and $2,000 air drier membrane replacement33 Compressor overhaul cost of $3,000, inflated at 10% per year Compressor overhaul cost of $3,000, inflated at 10% per year44 Value of gas = $3.00/Mcf Value of gas = $3.00/Mcf55 Net Present Value (NPV) based on 10% discount rate for 5 years Net Present Value (NPV) based on 10% discount rate for 5 years
Year 0 Year 1 Year 2 Year 3 Year 4 Year 5
Installation Cost ($) (45,750)
O&M Cost ($) 0 (13,140)1
(3,200)2
(13,140)
(3,200)
(13,140)
(3,200)
(13,140)
(3,200)
(13,140)
(3,200)
Overhaul Cost ($) 0 0 0 0 0 (4,800) 3
Total Cost ($) (45,750) (16,340) (16,340) (16,340) (16,340) (21,140)
Gas Savings ($) 0 71,000 4 71,000 71,000 71,000 71,000
Annual Cash Flow ($) (45,750) 54,660 54,660 54,660 54,660 49,860
Cumulative Cash Flow ($)
(45,750) 8,910 63,570 118,230 172,890 222,750
Payback Period (months) 10
IRR 117 %
NPV 5 $158,454
Page 17Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Partner Experience: Spirit Energy ‘76Partner Experience: Spirit Energy ‘76
Installed air compression system in its Fresh Installed air compression system in its Fresh Water Bayou facilityWater Bayou facility
Project Cost = $60,000Project Cost = $60,000 Emissions Reductions = 69,350 Mcf/yearEmissions Reductions = 69,350 Mcf/year Savings = $208,050 /year Savings = $208,050 /year Payback Period < 4 months Payback Period < 4 months
Page 18Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Partner Experience : TexacoPartner Experience : Texaco
Installed compressed air system to drive Installed compressed air system to drive pneumatic devices in 10 South Louisiana pneumatic devices in 10 South Louisiana facilitiesfacilities
Project Cost = $40,000Project Cost = $40,000 Emissions Reductions = 23,000 Mcf/yearEmissions Reductions = 23,000 Mcf/year Savings = $69,000 / year Savings = $69,000 / year Payback Period ~ 7 months Payback Period ~ 7 months
Page 19Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Lessons LearnedLessons Learned
Instrument air system has potential to Instrument air system has potential to increase revenue and cut methane emissionsincrease revenue and cut methane emissions
It may extend the life of system equipmentIt may extend the life of system equipment Installing low-bleed devices in conjunction Installing low-bleed devices in conjunction
with switch to instrument air is economicalwith switch to instrument air is economical Existing infrastructure can be usedExisting infrastructure can be used Rotary air compressors lubricated with oil Rotary air compressors lubricated with oil
must be filtered ahead of membrane dryermust be filtered ahead of membrane dryer
Page 20Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Other TechnologiesOther Technologies
Liquid nitrogen systemLiquid nitrogen system Expensive and potential safety hazardExpensive and potential safety hazard
Mechanical controls and instrumentation Mechanical controls and instrumentation systemsystem No power source neededNo power source needed Limited application, frequent calibration requiredLimited application, frequent calibration required
Electric and electro-pneumatic devicesElectric and electro-pneumatic devices
Page 21Reducing Emissions, Increasing Efficiency, Maximizing ProfitsReducing Emissions, Increasing Efficiency, Maximizing Profits
Discussion QuestionsDiscussion Questions
To what extent are you implementing this To what extent are you implementing this BMP?BMP?
How can this Lessons Learned study be How can this Lessons Learned study be improved upon or altered for use in your improved upon or altered for use in your operation(s)?operation(s)?
What are the barriers (technological, What are the barriers (technological, economic, lack of information, etc.) that are economic, lack of information, etc.) that are preventing you from implementing this preventing you from implementing this technology?technology?
