TOTAL CAPABILITIES IN THE PIPELINE INDUSTRY UTILITY TECHNOLOGIES INTERNATIONAL CORPORATION Cincinnati Columbus West Jefferson
Load Estimating 2
Therms/Day Weather-Load Relationship 10 9 8 7 6 Qsh = C (Tb-To) 5 4 3 2 1 0 0 10 20 30 40 50 60 70 80 Temperature - Degrees F 3
Service Loads Example (new home) 85,000 BTU furnace 40,000 BTU H 2 O 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 4
Service Loads (cont d) Example (Old home) 125,000 BTU furnace 75,000 BTU H 2 O Heater 60,000 BTU Range 20,000 BTU Clothes Dryer 280,000 BTU total = 280 scfh 5
Is it likely that all the appliances for a home will be on continuously for an entire hour? 6
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 8
Load profile for Residential space- heating 9
Likewise, is it likely all the homes in an area will experience their max our usage during the same hour? NO!
Load Curve 11
Coincidence 12
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
Ratio Load Factor 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 14
Daily-Annual Load Factor Total Annual Send Out Mcf 365 Maximum DailySend Out L d, y x / year Mcf / day Average percent use of gas supply facilities Higher the load factor implies lower $ per unit volume invested in the system supply facilities 100 15
Hourly-Annual Load Factor L h, y 365 Total Annual Send Out Mcf 24 Maximum Hourly Send / year x100 Out Mcf / hour Average percent use of gas distribution facilities Higher the load factor implies lower $ per unit volume invested in the distribution facilities 16
Typical load factors Table 3-3. Typical Load Factors for Gas Consumers Space Heating (northern U.S.) Type of Consumer Annual Load Factor (%) Based on: Maximum Daily Demand Maximum Hourly Demand 26 17 Cooking 72 16 Restaurant 84 53 Retail Store 63 21 Industrial Metal Products 79 45 17
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 18
Residential Heating Load Conversion Rule of Thumb 19
Estimating use for a building (other than a Home) 40 BTU/ft 2 Typical ceilings Thermostat set at 68 F to 70 F Higher ceilings slightly > 40 BTU/ft 2 Lower for warehouse temperature set at 50 F 20
Estimating use for a building (other than a Home) Sq ft BTU/ BTU /hr BTU/ cf/ MCF/ Sq ft Cf 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 22
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 23
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? P 2 P 1 = 50% 25
P2/P1 P2/P1 vs Utilized Capacity 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Utilized Capacity 26
How to use chart to estimate system performance on a design day 27
Demand (flow) Demand (flow) directly proportional to degree days Degree Days 28
Therms/Day Weather-Load Relationship 10 9 8 7 Qsh = C (Tb-To) 6 5 4 3 2 1 0 0 10 20 30 40 50 60 70 80 Temperature - Degrees F 29
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) 30
Problem solution P 2 P 1 = 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 = 102% X 65 5 #*&% 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) 32
Problem solution P 2 P 1 = 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 = 93.6% X 65 5 From chart, 93.6% capacity equates to P 2 P 1 = 25% P 2 = (P 1 * 25%) = (75 psig * 25%) = 18.75 psig 33
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 34
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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 38
Modeling Considerations (Cont.) 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) 39