Natural Gas: Dry vs. Wet

Natural Gas: Dry vs. Wet

Do you know the difference between dry and wet natural gas? While largely unrecognized but commonly
referenced, dry and wet natural gas serve uniquely distinct purposes in our everyday lives and our economy
places different values for each.

Dry Natural Gas is almost completely
methane. The higher the methane concentration
within the gas, the drier it is. According to the
U.S. Energy Information Administration (EIA),
dry natural gas is what remains after all of the
liquefied hydrocarbons (hexane, octane, etc.) and
non-hydrocarbon (helium, nitrogen, etc.) impurities
are removed from the natural gas stream. The
five largest dry gas-producing states are Texas,
New Mexico, Louisiana, Oklahoma and Wyoming.

When natural gas is discussed in the media, they
are typically referring to dry gas. Dry gas is typically
used in heating and cooling systems and for electrical
power generation. Once compressed, dry gas can
be used as vehicle fuel.

Wet Natural Gas contains less than
85% methane and has a higher percentage of
liquid natural gasses (LNG’s) such as ethane and
butane. The combination of LNG’s and liquefied
hydrocarbons give it the “wetness.” LNG’s are
separated from the methane and sold as individual
compounds. The five highest-yielding wet gas
states include Pennsylvania, Texas, Louisiana,
Oklahoma and Colorado.

LNG’s like butane can be used in refrigeration and
freezing systems, in torches for cooking purposes
and as fuel for lighters and grills. When burned,
both wet and dry natural gas produce fewer
emissions than coal or oil.

Although proved reserves of wet natural gas began
moderately increasing in the late 1990s, volumes
grew dramatically in the mid-2000s due to the
intensifying of horizontal drilling programs.

“Exploration and production (E&P) market
participants that contributed to a recent
market survey believe [dry] gas prices have
bottomed out and 87% of survey respondents
predicted [dry] natural gas prices would
stay the same or increase over the next two
years or increase by 10% or more in the
next five years. Until then, E&P companies
are moving away from dry gas and are
focusing instead on liquid-rich plays, such
as wet gas and shale oil.”

Source: U.S. Energy Information Administration, U.S. Crude Oil Natural Gas,
and Natural Gas Liquids Reserves, 1980 through 2010 annual reports.

#1 Distinguish between a “wet” gas and a “dry” gas.

Dry gas is almost completely composed of methane. It is what remains after all liquefied hydrocarbons and non-hydrocarbons impurities are removed from the system. They are used in heating and cooling systems for electrical power generation.

Wet gas on the other hand contains less than 85 % of methane and large percentages of it are liquid natural gases such as ethane and butane. They are used in refrigeration and freezing systems.

Source:

http://www.usenergydevcorp.com

Retrieved: http://www.usenergydevcorp.com/media_downloads/Natural%20Gas%20Dry%20Vs%20Wet_050913.pdf

#2 A bicycle tire contains nitrogen, oxygen and argon gases. If the partial pressures are 51.0 psi, 13.5 psi, and 0.5 psi, what is the total pressure (in atm)?

Dalton’s law (also called Dalton’s law of partial pressures) states that the total pressure exerted by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases.

so

Ptotal = Pnitrogen + Poxygen + Pargon

Ptotal = 51 + 13.5 + 0.5 psi

Ptotal = 65 psi

Converting it to atm:

1 atm = 14.7 psi

Ptotal = 65 psi (1 atm / 14.7 psi)

Ptotal = 4.42 atm (Final answer)

#3 The solubility of sugar is 110g/100g water at 30 degrees, Celcius. If a solution contains 95g of sugar in 25g of water at 30 degrees Celcius, is the solution saturated, unsaturated, or supersaturated?

Definitions:

Saturated solution:

A solution that can hold no more of the solute at a particular temperature is said to be a saturated    solution at that temperature.

Unsaturated solution:

An unsaturated solution is a solution, which contains less amount of solute than is required to saturate it  at that temperature.

Super Saturated solution

Solution that is more concentrated than a saturated solution is known as super saturated solution.

Source:

http://www.citycollegiate.com/chapter3g.htm

First we need to know how much sugar is only soluble with 25 g of water:

Sugar soluble = 25 g water (110 g sugar / 100 g water )

Sugar soluble = 27.5 g

Thus only 27.5 g of sugar is soluble, there is an excess of 95-27.5 = 67.5 g of sugar in the solution. Thus it is a supersaturated solution.

#4 What is the molar concentration of a saturated solution of calcium hydroxide that contains 0.185 g of solute in 100.0 ml of solution?

Molarity can be used to express molar concentration of a solution. By definition

Molarity (M) = moles solute / liters solution

Molar mass of calcium hydroxide (Ca (OH)2):

Ca = 40.078 g/mol

O = 16 g/mol

H = 1.008

So molar mass of Ca (OH)2 = 40.078 + 2(16 + 1.008 ) g/mol

Molar mass of Ca (OH)2 = 74.094

Molar mass = 74.094 g/mol

Now we find the number of moles in 0.185 g of (Ca (OH) 2:

Let x = number of moles

x = 0.185 g / 74.094 g/mol

x = 2.5×10-3 moles

Also we need to convert volume in terms of liters:

Volume = 100 ml ( 1 L/1000 m l) = 0.1 L

Going back to formula of concentration:

Molarity (M) = moles solute / liters solution

Molarity (M) = 2.5×10-3 moles / 0.1 L

Molarity (M) = 0.025 M (Final Answer)

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