natural gas system design natural gas system design for commercial and industrial applications march...
TRANSCRIPT
Natural Gas System Natural Gas System
Design Design
for Commercial and for Commercial and Industrial ApplicationsIndustrial Applications
March 16th 2006
www.piedmontng.com
Agenda: Supply – From the Wellhead to the Meter Properties of Natural Gas Service Fuel Piping
– Materials– Pipe Sizing– Pressure Regulation
Venting IFGC Code Updates
Supply
From the Wellhead to the Meter
What Is Natural Gas?
Combustible hydrocarbon gasses
Primarily methane (CH4)
Found in underground and undersea reservoirs – sometimes with crude oil wells
Result of long-time bacterial decomposition of plant and animal matter
24803
Petroleum System ElementsPetroleum System Elements
120° F120° F
350° F350° FGenerationGeneration
MigrationMigration
Seal RockSeal Rock
Reservoir RockReservoir Rock
OilOil
WaterWater
Gas CapGas Cap
EntrapmentEntrapment
Natural Gas Advantages
North American resource
Abundant worldwide
Wellhead Deregulated
Low impact underground infrastructure
Natural Gas Accounts for Roughly One-Fourth of U.S. Primary Energy Consumption
Sources of U.S. Gas Supply
U.S.84%
Canada15%
Liquified Natural Gas1%
The Impact of Severe Weather
Commodity Price Volatility
0
5,000
10,000
15,000
20,000
25,000
1973
1980
1990
2002
Wel
ls D
rille
d P
er Y
ear
$0.00
$0.50
$1.00
$1.50
$2.00
$2.50
$3.00
$3.50
$4.00
$4.50
Wel
lhea
d P
rice
(199
9 $)
Natural Gas Wells Drilled
Real Wellhead Price
Natural Gas Drilling Activity Responds to Market Price
Major Portions of the Gas Resource Base are Not Accessible
21TCF
346TCF
31TCF
43TCF
100%
40%
100%
56%
Approximately 29 trillion cubic feet (TCF) of the Rockies gas resources are closed to development and 108 TCF are available with restrictions.
RestrictedPercentage
Liquefied Natural Gas (LNG)
Vapor is refrigerated to – 260 degrees Fahrenheit into a liquid form.
Reduces volume 600 times
Freighted to a LNG port and injected as a vapor back into the supply system.
Existing World LNG infrastructure moves about 6 Tcf/Year (40 Terminals and 128 ships mainly serving Japan, South Korea and Europe)
Producing Wells
Gathering LinesTransmission Lines
Processing Plant
CompressorStations
UndergroundStorage
Large Volume Customer
Regulator/Meter
City Gate(Regulators/Meters)
LNGor Propane/Air Plant
Natural Gas Transportation System
Residential Customers
CommercialCustomer
Distribution Mains (Lines)
Gas Market Sectors
Residential 25%
Commercial 15%
Power Generation 25%
Industrial 35%
Piedmont Natural Gas
Properties of Natural Gas
Natural gas is 96% Methane gas - CH4
Also contains small percentages of:Ethane 2.1%Propane <1%Butane <1%Pentane <1%Hexane <1%Heptane <1%
Flammability range
Requires between 4% - 14.% natural gas in air for combustion.– Less than 4% not enough fuel (Too Lean)– More than 14% too much fuel (Too Rich)– Peak burn is a 10% gas to air ratio
Properties of Natural Gas
Ignition Temperature
Above 1100º - 1200º– Pilot Lights– Sparks– Cigarettes– Static Electricity
Properties of Natural Gas
Properties of Natural Gas
Lighter than air, always rises Air has a specific gravity of 1.0 Natural gas has a specific gravity of 0.6 Propane 1.54
• Specific gravity is the weight of a substance compared to the weight of some referenced substance.
Propane ButaneNatural Gas
(Methane)
Chemical Formula C3H8 C4H10 CH4
Specific Gravity (Liquid) .509 .582 .3
Specific Gravity (Vapor) 1.52 2.01 .60 -.64
Weight Per Gallon 4.24 LBS. 4.84 LBS. LNG 4 +/- LBS.
Boiling Point (Atmospheric) - 44° F 31° F -260° F
Ignition Temperature 950° – 1050°900° -
1000°1100° - 1200°
Maximum Flame Temperature 3595° F 3615° F 3400° F
* Flammability Limits (Upper) 9.60 % 8.60 % 15 %
* Flammability Limits (Lower) 2.15 % 1.55 % 4 %
Ideal Combustion Ratio (Air to Gas)
24 to 1 31 to 1 10 to 1
Heat Value Per Cubic Foot (Vapor)
2,516 BTU 3,280 BTU 1,035 BTU
Heat Value Per Pound (Liquid) 21,591 BTU 21,221 BTU 20,833 BTU
Properties of Natural Gas
Natural gas is:• Odorless• Colorless• Non-Toxic
– Only through the displacement of oxygen can it pose an asphyxia hazard
• Non-Poisonous
Properties of Natural Gas Add Mercaptan as an odorant to aid in leak detection.
– Requirements:• Non-poisonous• Non-corrosive• Has to be retained by the gas• Has to burn completely• Not absorbed by pipe or containers• No harmful products from combustion
½ lb.per million cubic feet of natural gas
Properties of Natural Gas
Environmentally friendly Blue flame indicates proper &
complete combustion By-products of complete
combustion– Carbon Dioxide– Water Vapor
• Both are the same substances produced when you exhale.
Properties of Natural Gas
Incomplete combustion of produces a yellow/orange flame. Carbon Monoxide (CH) is a product of incomplete combustion, which is:
• Toxic• Poisonous• Explosive
Delivery of Natural Gas Service
Service Tap on Gas MainSaddle Fusion Joint
Service Tracer Wire
Natural Gas Service
Customer Piping starts at meter outlet
Standard Delivery Pressures
• 7 inches Water Column (0.25Psi)
• 2 Pounds per Square Inch
• 5 Pounds per Square InchElevated delivery pressures require equipment requirement
documentation and engineering approval. Not allowed to
reduce pipe size.
Why designing with Natural Gas is good for everyone
Facts
Virtually all electric power plants built in the US in the last 10 years are fueled with Natural Gas
Natural Gas power plants are expected to supply 90% of added electric loads in the US for the next 20 years
Delivering Energy to the Site
Electricity
Natural Gas
DeliveredTo Customer
28%
91 %
InGround
Extraction,Processing, &Transportation
Losses
ConversionLosses
DistributionLosses
100%
100%
92% 28%
92% 1%0%
Natural Gas Power Plant Consumption
Natural Gas Power Plants often can consume as much natural gas on and hourly basis as an entire metropolitan city’s direct connected gas load
Wonder why Gas Prices have been volatile lately?
What can we do to conserve our Natural Resource?
Design with Natural Gas !
When you Drink the Water Remember the Spring
Chinese Proverb