TOTAL CAPABILITIES IN THE PIPELINE INDUSTRY

UTILITY TECHNOLOGIES INTERNATIONAL CORPORATION Cincinnati Columbus West Jefferson

Load Estimating

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Weather-Load Relationship

0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50 60 70 80

Temperature - Degrees F

Th

erm

s/D

ay

Qsh = C (Tb-To)

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Service Loads • Example (new home)

– 85,000 BTU furnace – 40,000 BTU H2O Heater – 50,000 BTU Range – 20,000 BTU Clothes Dryer – 30,000 BTU Gas Logs – 15,000 BTU Gas Grill 240,000 BTU total = 240scfh

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Service Loads (cont’d)

• Example (Old home)

– 125,000 BTU furnace

– 75,000 BTU H2O Heater

– 60,000 BTU Range

– 20,000 BTU Clothes Dryer

280,000 BTU total = 280 scfh

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Is it likely that all the appliances for a home will be on continuously for

an entire hour?

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Is it likely that all the appliances for a home will be on continuously for

an entire hour?

NO

Max hour-Typical Residence

• New – 60 scfh to 65 scfh

• Old – 100 scfh to 125 scfh

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Load profile for Residential space- heating

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Likewise, is it likely all the homes in an area will experience their max our usage during the same hour?

NO !

Load Curve

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Coincidence

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Sample Diversity factor

Number of customers

Heating diversity (demand) factors

1 1.0

5 .920

10 .868

25 .800

50 .784

100 .770

200 .750 13

Load Factor • Ratio

• Actual gas usage over a given time period, to

• Use that would have occurred if the maximum short term use rate in that period occurred over the entire period

• Daily-annual; hourly-annual; hourly-daily

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Daily-Annual Load Factor

100/365

/, x

dayMcfOutSendDailyMaximum

yearMcfOutSendAnnualTotalL yd

Average percent use of gas supply facilities

Higher the load factor implies lower $ per

unit volume invested in the system supply

facilities

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Hourly-Annual Load Factor

hourMcfOutSendHourlyMaximum

xyearMcfOutSendAnnualTotalL yh

/24365

100/,

Average percent use of gas distribution facilities

Higher the load factor implies lower $ per unit

volume invested in the distribution facilities

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Typical load factors

Table 3-3. Typical Load Factors for Gas Consumers

Annual Load Factor (%) Based on:

Type of Consumer

Maximum Daily Demand

Maximum Hourly Demand

Space Heating

(northern U.S.)

26 17

Cooking 72 16

Restaurant 84 53

Retail Store 63 21

Industrial Metal Products 79 45

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Estimating max hour from annual usage

• Restaurant’s Annual usage = 2,000 Mcf

• Average load factor for a restaurant ≈ .53

• LF = annual use/(365x24x max hr)

• Max hr = annual use /(365x24x0.53)

• Max hr = 2,000 Mcf /(365x24x0.53)

• Max hr = 0.431 Mcfh = 431 scfh

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Residential Heating Load Conversion Rule of Thumb

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Estimating use for a building (other than a Home)

• 40 BTU/ft2

– Typical ceilings

– Thermostat set at 68°F to 70°F

• Higher ceilings slightly > 40 BTU/ft2

• Lower for warehouse temperature set at 50°F

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Estimating use for a building (other than a Home)

Sq ft BTU/

Sq ft

BTU /hr

BTU/

Cf

cf/

MCF

MCF/

hr

10,000 40 40,000 1000 1000 0.4

20,000 40 80,000 1000 1000 0.8

50,000 40 200,000 1000 1000 2.0

100,000 40 4,000,000 1000 1000 4.0

200,000 40 8,000,000 1000 1000 8.0

500,000 40 2,000,000 1000 1000 20.0 21

Load profile for Commercial customers

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Estimating Load for undeveloped area

• 1.5 to 1.8 meters per acre

• Takes into account road, utility corridors, retention ponds, parks, etc.

• Fully developed

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Gas Flow & Pipe Sizing

Gas Flow

If your pipeline is moving 40 Mcfh starting at a pressure of 50 psig and delivering at a pressure of 25 psig, how much additional capacity remains on this segment of pipe?

𝑃2𝑃1

= 50%

25

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

P2

/P1

Utilized Capacity

P2/P1 vs Utilized Capacity

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How to use chart to estimate system performance on a design

day

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Dem

and (

flow

)

Degree Days

Demand (flow) directly proportional to degree days

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Weather-Load Relationship

0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50 60 70 80

Temperature - Degrees F

Th

erm

s/D

ay

Qsh = C (Tb-To)

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Problem:

• At a temperature of 15 degrees F, a pressure of 30 psig is recorded at the end of a 75 psig system.

• What pressure would you expect at a design temperature of 5 degrees F?

(hint: think of % capacity as directly corresponding to demand or flow)

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Problem solution •

𝑃2

𝑃1=

30

75= 40%

• From chart, utilizing 85% of pipeline capacity

• Think of % capacity as demand which is proportional to degree days or degree hours.

•85%

65−15=

𝑋

65−5

• X = 102%

• #*&% We ran out of pipeline capacity! 31

Same Problem:

• Only this time a pressure of 40 psig is recorded at the end of a 75 psig system when the temperature is 15°F.

• What pressure would you expect at a design temperature of 5 degrees F?

(again: think of % capacity as directly corresponding to demand or flow)

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Problem solution •

𝑃2

𝑃1=

40

75= 53.3%

• From chart, utilizing 78% of pipeline capacity

• Think of % capacity as demand which is proportional to degree days or degree hours.

•78%

65−15=

𝑋

65−5

• X = 93.6%

• From chart, 93.6% capacity equates to 𝑃2

𝑃1 = 25%

• P2 = (P1 * 25%) = (75 psig * 25%) = 18.75 psig

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Flow Modeling Software • GasWorks • SynerGEE Gas • Stoner Pipeline Simulator (SPS) • AFT Aarow • Pipeline Studio • Pipe-Flo • Gregg Engineering (Multiple Programs)

• GasCalc • Pipeline Toolbox (Gas, Liquid, Enterprise) • QuickConvert

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Modeling Considerations • Station pressures (drop across M&R Settings) • Load Estimating • Pipe Type & Length

– Plastic or Steel – Wall thickness

• Pipe Efficiency Factor – Typically use 0.90-0.95 efficiency factor for distribution system

using IGT Improved Equation

• Fittings • Regulators • Compressors • Valves

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• Flow Equations

– Spitzglass (Low Pressure) • Low pressures (inches of water column) • 12” and smaller • Assumes smooth pipe flow

– Spitzglass (High Pressure) • Medium and high pressures • Very conservative

– IGT Improved • Very good distribution equation • 3”-30” Low Pressure • 1 ½” – 20” (2-100 psig)

– Weymouth • Use for early evaluation • Very Conservative • Good for high pressure supply lines 10” – 30” rough pipe

– Panhandle A • Good for ≥ 16” and ≥20 psig • Better for high pressure lines • Relatively good equation but is slightly optimistic

– Mueller • Services • 3

8 ” – 2” (2-100 psig)

Modeling Considerations (Cont.)

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