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19 Cards in this Set
- Front
- Back
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Natural gas (Ch4) consists of |
- Methane 87.40 % - Ethane 6.80 % |
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What is the formula for natural gas? |
usually represented by the chemical formula methane (CH4) |
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What is Propane ? |
Refined hydrocarbons stored and transported as a liquid under pressure. LP is vaporized into a fuel gas when released for use. |
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Chemical formula for Propane |
C3H8 |
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What are the common properties of Natural gas (CH4) & Propane (C3H8) ? |
Nontoxic, tasteless, invisible and odourless. |
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What is added to nat gas. and LP to make it detectable? How much is added? |
Mercaptan - to detect the gas leak below its lower flammable limit, approximately ONE POUND OF MERCAPTAN is added to every ONE MILLION CUBIC FEET OF GAS. |
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What are the Physical Properties of fuel gases? |
- Specific Gravity - Expansion Factors - Boiling Point - Temperature and pressure relationships - Calorific value (heat content) |
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Describe Specific Gravity |
Specific gravity or relative density is the comparison between the weight of the volume of a vapour or liquid and the weight of an equal volume of air or water. |
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Why must i know the specific gravity of a particular gas? |
- Checking for gas leaks - Calculating flows through gas piping systems - Sizing orifices |
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What must be done when comparing the specific gravity of air and gas? |
Both must be at the same pressure and temperature. |
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When being compared to air what are the relative density (specific gravity) of natural gas and propane? |
Air = 1 Natural gas= 0.55 Propane= 1.52 |
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Propane compared to water |
Water= 1 Propane= 0.51 |
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When fuel changes from a liquid to a gas, a tremendous expansion takes place. At atmospheric pressure, the expansion of gases is at a ratio of: |
Natural gas liquid to gas 1 : 600 Propane liquid to gas 1 : 270 |
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What is Calorific Value (Heat Content) ?? |
The calorific value (heat content) of fuel is usually described as the energy released when a given volume of fuel is burned. A Btu is the amount of heat required to raise the temperature of 1Ib of water 1 degree fahrenheit |
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Calorific values for natural gas and propane are: |
Natural gas = 1000 Btu/ft3 Propane = 2520 Btu/ft3 |
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Identify Combustion data related to the physical properties of natural gas and propane: |
- Limits of flammability - Ignition temperature - Flame temperature - Flame speed |
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Describe limits of flammability |
are the upper and lower ranges of gas in the air-gas mixture that will support combustion. |
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Why is it import an to know limits of flammability ? |
In order to supply the correct amount of air to gas burners, or to troubleshoot burner problems. It is also key when responding to a gas leakage call. |
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Describe lower flammable limit |
is defined as the weakest air-gas mixture that will burn. The upper limit is the strongest air-gas mix that will produce and sustain combustion. |
