Pipeline Pumpdown Practices and Hot Taps Lessons Learned from Natural Gas STAR Transmission...

Pipeline Pumpdown Practices and Hot TapsPipeline Pumpdown Practices and Hot Taps

Lessons LearnedLessons Learnedfrom Natural Gas STARfrom Natural Gas STAR

Transmission Technology Transfer WorkshopTransmission Technology Transfer Workshop

Duke Energy Gas Transmission,Duke Energy Gas Transmission,

Interstate Natural Gas Association of America (INGAA) andInterstate Natural Gas Association of America (INGAA) and

EPA’s Natural Gas STAR ProgramEPA’s Natural Gas STAR Program

September 22, 2004September 22, 2004

Reducing Emissions, Increasing Efficiency, Maximizing Profits

Pipeline Practices: AgendaPipeline Practices: Agenda

Methane LossesMethane Losses Methane Recovery by PumpdownMethane Recovery by Pumpdown Is Recovery Profitable?Is Recovery Profitable? Industry ExperienceIndustry Experience Methane Recovery by Hot TapsMethane Recovery by Hot Taps Is Recovery Profitable?Is Recovery Profitable? Industry ExperienceIndustry Experience Discussion QuestionsDiscussion Questions


Methane Losses from Current Pipeline Methane Losses from Current Pipeline Maintenance PracticeMaintenance Practice

Methane is often vented to the atmosphere in Methane is often vented to the atmosphere in preparation for pipeline maintenance or new preparation for pipeline maintenance or new connectionsconnections

The smallest possible linear section of pipeline is The smallest possible linear section of pipeline is blocked in, and the natural gas contents, often under blocked in, and the natural gas contents, often under high pressure, are depressured to the atmospherehigh pressure, are depressured to the atmosphere

““Hot work” may require purging the pipeline with inert Hot work” may require purging the pipeline with inert gasgas

These practices results in methane emissionsThese practices results in methane emissions Loss of SalesLoss of Sales Occasionally cause customer inconvenienceOccasionally cause customer inconvenience Costs associated with evacuating the existing piping Costs associated with evacuating the existing piping

systemsystem Nationally, 9 billion cubic feet (Bcf) of methane are Nationally, 9 billion cubic feet (Bcf) of methane are

vented during routine annual maintenance and vented during routine annual maintenance and pipeline upsetspipeline upsets


Methane Recovery by Pipeline Methane Recovery by Pipeline PumpdownPumpdown

Use pipeline compressors to “pull down” the Use pipeline compressors to “pull down” the pressure to minimum suction pressurepressure to minimum suction pressure

Use portable compressor to “pull down” Use portable compressor to “pull down” pressure even furtherpressure even further

Cost is justified by immediate payback in gas Cost is justified by immediate payback in gas savingssavings

About 90% of the gas usually vented is About 90% of the gas usually vented is recoverablerecoverable

In 1998 Gas STAR Partners reported In 1998 Gas STAR Partners reported savings of 1.1 Bcf methanesavings of 1.1 Bcf methane


Sequence of De-pressurization EventsSequence of De-pressurization Events


Pipeline Pumpdown TechniquePipeline Pumpdown Technique

In-line pipeline compressorIn-line pipeline compressor Typically has compression ratio of 2 to 1Typically has compression ratio of 2 to 1 By blocking upstream valve the pressure in the By blocking upstream valve the pressure in the

pipeline is reduced to safe limits for some pipeline is reduced to safe limits for some maintenancemaintenance

Portable compressorPortable compressor Typically has compression ratio of 5 to 1Typically has compression ratio of 5 to 1 Can be used in conjunction with in-line compressor to Can be used in conjunction with in-line compressor to

further reduce pressure in the pipeline sectionfurther reduce pressure in the pipeline section Justifiable only when multiple sections of pipeline are Justifiable only when multiple sections of pipeline are

to be serviced (i.e. long sections of maintenance or to be serviced (i.e. long sections of maintenance or pipeline valve station maintenance where stopples are pipeline valve station maintenance where stopples are not feasible)not feasible)


Applicability of Pipeline Pumpdown Applicability of Pipeline Pumpdown TechniquesTechniques

Repair Repair ClassClass

Pump-Down Pump-Down Technique Technique Description of ApplicabilityDescription of Applicability

Class 1Class 1In-line and In-line and PortablePortable

Repairs primarily involve non-Repairs primarily involve non-emergency situationsemergency situations

Class 2Class 2

Class 3Class 3 In-line onlyIn-line onlyInvolves emergency repair with Involves emergency repair with no time for mobilization of no time for mobilization of portable compressorsportable compressors

Class 4Class 4 In-line onlyIn-line only

Involves large projects with Involves large projects with new lines running parallel to new lines running parallel to old ones with opportunity to old ones with opportunity to recover gas from old pipelines recover gas from old pipelines during startup of new pipelineduring startup of new pipeline


Calculate Gas Vented by Calculate Gas Vented by Depressuring PipelineDepressuring Pipeline

Estimate the quantity and value of gas that Estimate the quantity and value of gas that would be lostwould be lost Given:Given:

Pipeline length (L) = 10 milesPipeline length (L) = 10 miles Pipeline internal diameter (I) = 2.375 feetPipeline internal diameter (I) = 2.375 feet Pipeline operating pressure (P) = 600 pounds per square Pipeline operating pressure (P) = 600 pounds per square

inch gauge (psig)inch gauge (psig) In-line compressor compression ratio (Ri) = 2In-line compressor compression ratio (Ri) = 2

Calculate amount of gas in pipeline (M):Calculate amount of gas in pipeline (M):

M = L*(5,280 ft/mile) * (M = L*(5,280 ft/mile) * (ππ * I * I22/4) * (P/14.7 psig) * (1 /4) * (P/14.7 psig) * (1 Mcf/1,000 cf)Mcf/1,000 cf)

M = (10*5,280) * (M = (10*5,280) * (ππ*2.375*2.37522)/4 * (600+14.7)/14.7 * 1/1,000)/4 * (600+14.7)/14.7 * 1/1,000

M = 9,781 McfM = 9,781 Mcf


Calculate Gas Saved with In-line Calculate Gas Saved with In-line CompressorsCompressors

Gas recoverable using an in-line compressor Gas recoverable using an in-line compressor (Ni)(Ni)

Ni = M – (M/Ri) = 9,781 – (9,781/2) = 4,891 McfNi = M – (M/Ri) = 9,781 – (9,781/2) = 4,891 Mcf

Value of gas recovered using an in-line Value of gas recovered using an in-line compressor (Vi)compressor (Vi)

Vi = Ni * $3/Mcf = 4,891 * 3 = $14,673Vi = Ni * $3/Mcf = 4,891 * 3 = $14,673

Annual value of gas recovered assuming 4 Annual value of gas recovered assuming 4 actions per monthactions per month

= $14,673 * 4 * 12 = $704,304= $14,673 * 4 * 12 = $704,304


Calculate Gas Saved with Portable Calculate Gas Saved with Portable CompressorCompressor

Calculate the volume and value of the gas Calculate the volume and value of the gas recovered by a portable compressorrecovered by a portable compressor Given:Given:

Portable compressor compression ratio (Rp) = 8Portable compressor compression ratio (Rp) = 8 Rate of compressor = 416 Mcf / hourRate of compressor = 416 Mcf / hour

Gas available for recoveryGas available for recovery

= M – Ni = 9,781 – 4,891 = 4,890 Mcf= M – Ni = 9,781 – 4,891 = 4,890 Mcf Gas recoverable using a portable compressorGas recoverable using a portable compressor

Np = Ni – (Ni / Rp) = 4,891 – (4,891 / 8) = 4,280 McfNp = Ni – (Ni / Rp) = 4,891 – (4,891 / 8) = 4,280 Mcf

Value of gas recovered using portable Value of gas recovered using portable compressorcompressor

Vg = Np * $3/ Mcf = 4,294 * 3 = $ 12,840Vg = Np * $3/ Mcf = 4,294 * 3 = $ 12,840


Steps to Evaluate the use of In-line Steps to Evaluate the use of In-line and Portable Compressorsand Portable Compressors

Verify technical feasibility of using a portable Verify technical feasibility of using a portable compressorcompressor Check for available connections to bleeder Check for available connections to bleeder

valves upstream and downstream of a mainline valves upstream and downstream of a mainline block valveblock valve

Determine the appropriate-sized portable Determine the appropriate-sized portable compressor for the projectcompressor for the project Amount of gas to be recoveredAmount of gas to be recovered Discharge pressure requirementsDischarge pressure requirements ScheduleSchedule


Cost of a Portable CompressorCost of a Portable Compressor

Check the availability and cost of purchasing (Vcp) Check the availability and cost of purchasing (Vcp) or leasing a portable compressoror leasing a portable compressor

Portable Compressor Purchase and Lease Cost Range*Portable Compressor Purchase and Lease Cost Range*

1,000 psig – High Flow1,000 psig – High Flow 600 psig – Medium Flow600 psig – Medium Flow 300 psig – Low Flow300 psig – Low Flow

PurchasePurchase LeaseLease PurchasePurchase LeaseLease PurchasePurchase LeaseLease

$2 - $5 $2 - $5 millionmillion

$60,000 - $60,000 - $150,000 $150,000 per monthper month

$0.8 - $1.2 $0.8 - $1.2 millionmillion


$400,000 - $400,000 - $600,000$600,000


*Based on assumptions that purchase cost does not include cost of freight or *Based on assumptions that purchase cost does not include cost of freight or installation and that lease cost is 3 percent of purchase costinstallation and that lease cost is 3 percent of purchase cost


O&M Costs of a Portable CompressorO&M Costs of a Portable Compressor

Estimate the operating costs associated with Estimate the operating costs associated with using a portable compressorusing a portable compressor Fuel costs (mostly natural gas) (Vcf) Fuel costs (mostly natural gas) (Vcf)

7,000 – 8,400 British thermal unit (Btu) per brake 7,000 – 8,400 British thermal unit (Btu) per brake horse power per hourhorse power per hour

Maintenance costs (Vcm)Maintenance costs (Vcm)$4 - $9 per horsepower per month$4 - $9 per horsepower per month

Labor costs (Vcl)Labor costs (Vcl) Taxes and administrative costs (Vct)Taxes and administrative costs (Vct) Installation costs (Vci)Installation costs (Vci) Freight costs (Vcs)Freight costs (Vcs)


Calculate Annual SavingsCalculate Annual Savings

Calculate total gas savingsCalculate total gas savings Gross value of gas recoverable during a 12- Gross value of gas recoverable during a 12-

month period, assuming average of 4 pump-month period, assuming average of 4 pump-downs per monthdowns per month

= Vg * 4 * 12 = Vg * 4 * 12

= $12881 * 4 * 12 = $12881 * 4 * 12

= $ 618,288 per year= $ 618,288 per year


Calculate Fuel CostsCalculate Fuel Costs Compressor fuel costsCompressor fuel costs

Hours portable compressor will operateHours portable compressor will operate= Np / rate of compressor = 4,294 / 416= Np / rate of compressor = 4,294 / 416= 10 hours= 10 hours

Given: Given: Fuel consumption = 7,000 Btu/hr/horsepowerFuel consumption = 7,000 Btu/hr/horsepower Natural gas heat content = 1,020 Btu/cfNatural gas heat content = 1,020 Btu/cf Compressor rating = 1,000 horsepowerCompressor rating = 1,000 horsepower

Fuel used by compressor for 10 mile stretch per monthFuel used by compressor for 10 mile stretch per month= = 69 Mcf= = 69 Mcf

Fuel costs assuming four 10-mile stretches per month Fuel costs assuming four 10-mile stretches per month = $ 3/Mcf * 69 Mcf * 4= $ 3/Mcf * 69 Mcf * 4= $828 per month= $828 per month

(7 ,0 0 0 B tu / h p / h o u r * 1 ,0 0 0 h p * 1 0 h o u rs)

(1 ,0 2 0 B tu / c f * 1 0 0 0 c f / M cf)


Is Recovery Profitable?Is Recovery Profitable? Calculate total annual costs for portable compressorCalculate total annual costs for portable compressor

Total cost of using the portable compressor during a 12 Total cost of using the portable compressor during a 12 month periodmonth period= Fuel costs + lease and maintenance costs + freight costs= Fuel costs + lease and maintenance costs + freight costs= 12 * ($828 + $24,000) + $15,000= 12 * ($828 + $24,000) + $15,000= $312,936= $312,936

Compare savings with costsCompare savings with costs Total net value of recovered gas during a 12- month lease Total net value of recovered gas during a 12- month lease

using a portable compressorusing a portable compressor= gross value of recovered gas – cost of using a portable = gross value of recovered gas – cost of using a portable compressorcompressor= $618,288 - $312,936 = $ 305,352= $618,288 - $312,936 = $ 305,352

Net savingsNet savings= inline + portable = $706,608 + $ 305,352= inline + portable = $706,608 + $ 305,352= $1,011,960= $1,011,960


Partner ExperiencePartner Experience

Partner used compressors at one location Partner used compressors at one location three times in 1998three times in 1998

Estimated cost = $52,600Estimated cost = $52,600 Gas saved from being vented = 32,550 McfGas saved from being vented = 32,550 Mcf Net savings = $40,600Net savings = $40,600 Estimated payback period ~ 16 monthsEstimated payback period ~ 16 months


Hot Taps: AgendaHot Taps: Agenda

Methane Recovery by Hot TapsMethane Recovery by Hot Taps Is Recovery Profitable?Is Recovery Profitable? Industry ExperienceIndustry Experience Discussion questionsDiscussion questions


What Are Hot Taps?What Are Hot Taps?

New branch connection while the pipeline remains in New branch connection while the pipeline remains in serviceservice Attach a branch connection and valve to the main Attach a branch connection and valve to the main

pipelinepipeline Cut-out a section of the main pipeline wall through the Cut-out a section of the main pipeline wall through the

valve to connect the branch to the main pipelinevalve to connect the branch to the main pipeline

Current technology has improved reliability and Current technology has improved reliability and reduced complicationsreduced complications


Schematic of Hot Tapping MachineSchematic of Hot Tapping Machine


Hot Tapping MachineHot Tapping Machine

Drilling MachineDrilling Machine Consists of a mechanically driven telescopic boring Consists of a mechanically driven telescopic boring

bar with a pilot drill and cutting tool (hole saw)bar with a pilot drill and cutting tool (hole saw) Pilot drill makes a pilot hole which guides the hole saw Pilot drill makes a pilot hole which guides the hole saw

to cut out the curved section of the pipelineto cut out the curved section of the pipeline

Branch fittingBranch fitting Consists of a simple welded nipple for a small Consists of a simple welded nipple for a small

connections to full-encirclement split-sleeve tee for connections to full-encirclement split-sleeve tee for same sized connectionsame sized connection

Valve Drilling MachineValve Drilling Machine Block or gate valve (but NOT plug or butterfly valve), Block or gate valve (but NOT plug or butterfly valve),

with enough space to extract the couponwith enough space to extract the coupon


Hot Tapping ProcedureHot Tapping Procedure

Connect fitting and permanent valve on the Connect fitting and permanent valve on the existing pipeline existing pipeline

Install hot tapping machine through the valveInstall hot tapping machine through the valve Perform hot tap and extract couponPerform hot tap and extract coupon Close valve and remove hot tapping Close valve and remove hot tapping

machinemachine Connect branch lineConnect branch line


Hot Tap BenefitsHot Tap Benefits

Continuous system operation – shutdown Continuous system operation – shutdown and service interruptions are avoidedand service interruptions are avoided

No gas released to the atmosphereNo gas released to the atmosphere Avoided cutting, realignment and re-welding Avoided cutting, realignment and re-welding

of pipeline sectionsof pipeline sections Reduction of costs associated with planning Reduction of costs associated with planning

and co-ordination and co-ordination Increased worker safetyIncreased worker safety Elimination of obligations to notify of gas Elimination of obligations to notify of gas

outageoutage


Calculate Natural Gas SavedCalculate Natural Gas Saved

Calculate cost of performing a shutdown interconnectCalculate cost of performing a shutdown interconnect Volume of natural gas lostVolume of natural gas lost

VVgg = =

Given: A pipeline company requires numerous shutdown Given: A pipeline company requires numerous shutdown or hot tap connections as follows:or hot tap connections as follows:

First example from tableFirst example from table

VVgg = = 22 Mcf/ connection = = 22 Mcf/ connection

D P L2

1 0 0 0 0 3 7 2

1 0 0 0

* * , * .

,

4 3 5 0 2 5 2 8 01 0 0 0 0 3 7 2

1 0 0 0

2 * * * ,, * .

,

Pipeline diameter (D) = 4 inches Pipeline diameter (D) = 4 inches 44 88 1010 1818

Pipeline pressure (P) = 350 psigPipeline pressure (P) = 350 psig 350350 100100 1,0001,000 200200

Pipeline length (L), milesPipeline length (L), miles 22 11 33 22

Annual tapsAnnual taps 250250 3030 2525 1515


Assessing Hot Tap EconomicsAssessing Hot Tap Economics

Avoided purge gas (assumed to be nitrogen)Avoided purge gas (assumed to be nitrogen)

VVpgaspgas = = = 2 Mcf = = = 2 Mcf

Value of natural gas saved and purge gas avoidedValue of natural gas saved and purge gas avoided Given:Given:

Cost of natural gas (CCost of natural gas (Cgg) = $3/Mcf) = $3/Mcf Cost of nitrogen (CCost of nitrogen (Cpgaspgas) = $4/Mcf) = $4/Mcf

Value of gas saved by hot tap (including purge gas)Value of gas saved by hot tap (including purge gas)Cost = CCost = Cgg + C + Cpgaspgas = V = Vgg * P * Pgg + V + Vpgaspgas * P * Ppgaspgas

= (22 *3) + (2 * 4)= (22 *3) + (2 * 4)

= $74= $74

D L2

1 8 3

1 0 0 02 2

*

,* .

4 2 5 2 8 0

1 8 3

1 0 0 02 2

2 * * ,

,* .


Costs of Hot Tap EquipmentCosts of Hot Tap Equipment

Calculate the cost of a hot tap procedureCalculate the cost of a hot tap procedure Cost of the hot tap equipment purchase and O&M OR Cost of the hot tap equipment purchase and O&M OR

cost of hot tapping contractcost of hot tapping contract Purchase costs vary from $13,200 to $23,000Purchase costs vary from $13,200 to $23,000

Connection Connection SizeSize

Capital Costs ($)Capital Costs ($)Contracting Contracting Service Cost ($)Service Cost ($)

Equipment O&M Equipment O&M Cost ($/yr)Cost ($/yr)MachineMachine11 MaterialMaterial

Small Taps Small Taps (<12”)(<12”)

13,200 – 13,200 – 23,00023,000 ---- ---- 500 – 5,000500 – 5,000

Large Taps Large Taps (>12”)(>12”)

100,000 – 100,000 – 200,000200,00022

2,000 – 2,000 – 9,1209,12022

1,000 – 4,0001,000 – 4,000----

11 Hot tap machines can last from 5 to 40 years. A company can perform as many as 400 small Hot tap machines can last from 5 to 40 years. A company can perform as many as 400 small taps per year.taps per year.

2 Most companies will find it more economical to contract out large hot tapping jobs, and 2 Most companies will find it more economical to contract out large hot tapping jobs, and would not therefore incur these costs.would not therefore incur these costs.

Note: Cost information provided Hot Tap manufacturers and contractors. Prices only provided Note: Cost information provided Hot Tap manufacturers and contractors. Prices only provided for most economic options.for most economic options.


Total Costs for Hot TappingTotal Costs for Hot Tapping

Calculate various costsCalculate various costs Given:Given:

Equipment cost per machine = $18,100Equipment cost per machine = $18,100 Operations and Maintenance (O&M) cost per Operations and Maintenance (O&M) cost per

machine = $2,750machine = $2,750 Contract Services cost per tap = $2,500Contract Services cost per tap = $2,500 Number of hot tap machines = 2Number of hot tap machines = 2 Number of contracted taps = 15 (all taps 12 inches Number of contracted taps = 15 (all taps 12 inches

and larger)and larger)

Total equipment cost = $18,100 * 2 = $36,200Total equipment cost = $18,100 * 2 = $36,200 Total O&M cost = $2,750 * 2 = $5,500Total O&M cost = $2,750 * 2 = $5,500 Contract Service cost = $2,500 * 15 = $37,500Contract Service cost = $2,500 * 15 = $37,500


Annual Hot Tap Program SavingsAnnual Hot Tap Program Savings

Evaluate the gas savings benefits of hot Evaluate the gas savings benefits of hot tappingtapping

Estimated Annual Gas Savings for the Hypothetical ScenarioEstimated Annual Gas Savings for the Hypothetical Scenario

Tap ScenarioTap Scenario Annual Annual Tap Tap

NumberNumber

Natural Gas Natural Gas SavingsSavings

Purge Gas Purge Gas SavingsSavings

Total Gas Total Gas SavingsSavings

PipelinePipeline Per tap Per tap McfMcf

Annual Annual McfMcf

Per tap Per tap McfMcf

Annual Annual McfMcf $$

4” pipeline, 350 psig, 4” pipeline, 350 psig, 2 mile line2 mile line 250250 2222 5,5005,500 22 500500 18,50018,500

8” pipeline, 100 psig, 8” pipeline, 100 psig, 1 mile line1 mile line 3030 1313 390390 44 120120 1,6501,650

10” pipeline, 1,000 10” pipeline, 1,000 psig, 3 mile linepsig, 3 mile line 2525 589589 14,72514,725 1919 475475 46,07546,075

18” pipeline, 200 18” pipeline, 200 psig, 2 mile linepsig, 2 mile line 1515 255255 3,8253,825 4141 615615 13,93513,935

Total AnnualTotal Annual 320320 24,44024,440 1,7101,710 80,16080,160


Is Recovery Profitable?Is Recovery Profitable? Compare the options and determine the Compare the options and determine the

economics of hot tappingeconomics of hot tappingEconomic Analysis of Hot Tap Versus ShutdownEconomic Analysis of Hot Tap Versus Shutdown

Year 0Year 0 Year 1Year 1 Year 2Year 2 Year 3Year 3 Year 4Year 4 Year 5Year 5

Capital Cost, $Capital Cost, $ (36,200)(36,200) 00

Contract Service Cost,$Contract Service Cost,$ 00 (37,500)(37,500) (37,500)(37,500) (37,500)(37,500) (37,500)(37,500) (37,500)(37,500)

O&M Cost, $O&M Cost, $ 00 (5,500)(5,500) (5,500)(5,500) (5,500)(5,500) (5,500)(5,500) (5,500)(5,500)

Total Cost, $Total Cost, $ (36,200)(36,200) (43,000)(43,000) (43,000)(43,000) (43,000)(43,000) (43,000)(43,000) (43,000)(43,000)

Natural Gas Savings, $Natural Gas Savings, $ 73,20073,200 73,20073,200 73,20073,200 73,20073,200 73,20073,200

Inert Gas Savings, $Inert Gas Savings, $ 6,8406,840

Net Benefit, $Net Benefit, $ (36,200)(36,200) 37,16037,160

Payback (months)Payback (months) 1212

IRRIRR 113 %113 %

NPVNPV11 $104,665$104,665

11Net Present Value (NPV) based on 10% discount rate for 5 yearsNet Present Value (NPV) based on 10% discount rate for 5 years


Vendor ExperienceVendor Experience

One vendor reported helping a gas One vendor reported helping a gas transmission client avoid a service outagetransmission client avoid a service outage One day gas delivery in a 36 inch natural gas One day gas delivery in a 36 inch natural gas

pipeline operating at 1,000 psig is worth pipeline operating at 1,000 psig is worth $365,000 in gross revenue$365,000 in gross revenue

Performing a shut down connection required Performing a shut down connection required 4 days4 days

Revenue savings was estimated at $1.5 Revenue savings was estimated at $1.5 millionmillion

This is in addition to the economics of hot This is in addition to the economics of hot tapping discussed earliertapping discussed earlier


Discussion QuestionsDiscussion Questions

To what extent are you implementing this BMP?To what extent are you implementing this BMP?

How can this BMP be improved upon or altered for How can this BMP be improved upon or altered for use in your operation(s)?use in your operation(s)?

What are the barriers (technological, economic, lack What are the barriers (technological, economic, lack of information, regulatory, etc.) that are preventing of information, regulatory, etc.) that are preventing you from implementing this technology?you from implementing this technology?

Pipeline Pumpdown Practices and Hot Taps Lessons Learned from Natural Gas STAR Transmission...

Documents

Transcript of Pipeline Pumpdown Practices and Hot Taps Lessons Learned from Natural Gas STAR Transmission...