CSG Uses

Gas Uses

Power generation

Natural gas is a major source of electricity generation. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Natural gas burns more cleanly than other Hydrocarbon fuels, such as oil and coal, and produces less carbon dioxide per unit of energy released. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. Combined cycle power generation using natural gas is thus the cleanest source of power available using hydrocarbon fuels and this technology is widely used wherever gas can be obtained at a reasonable cost. 

Gas Fired Power Generation

Undoubtedly, high efficiency natural gas-fired power stations can produce up to 70% lower greenhouse gas emissions than existing brown coal-fired generators, and less than half the greenhouse gas emissions of the latest technology black coal-fired power stations. Notice the distinction between black and brown coal, however, exactly how much less CO2 also depends upon the type of gas-fired station.

There are three main types: the steam boiler, the gas turbine and the combined cycle. The most efficient natural gas turbines are the combined cycle plants where hot exhaust gases are used to raise steam in a waste heat boiler. A combined-cycle gas turbine power plant consists of one or more gas turbine generators equipped with heat recovery steam generators to capture heat from the gas turbine exhaust. Steam produced in the heat recovery steam generators powers a steam turbine generator to produce additional electric power. Use of the otherwise wasted heat in the turbine exhaust gas results in high thermal efficiency compared to other combustion based technologies. 

The CO₂ emissions from Natural Gas Combined Cycle (NGCC) plants are reduced relative to those produced by burning coal given the same power output because of the higher heat content of natural gas, the lower carbon intensity of gas relative to coal, and the higher overall efficiency of the NGCC plant relative to a coal-fired plant.

Compared to the average air emissions from coal-fired generation, natural gas produces half as much carbon dioxide, less than a third as much nitrogen oxides, and one percent as much sulphur oxides at the power plant.

In the gas vs coal debate... gas is a viable option in the short-medium term, with renewable energy the solution in the long term.

http://www.global-greenhouse-warming.com/gas-vs-coal.html

Domestic use

Natural gas is supplied to homes where it is used for such purposes as cooking in natural gas-powered ranges and ovens, natural gas-heated clothes dryers, heating/cooling and central heating. Home or other building heating may include boilers, furnaces, and water heaters. Compressed natural gas (CNG) is used in rural homes without connections to piped-in public utility services, or with portable grills.

Transportation

CNG is a cleaner alternative to other automobile fuels such as petro) and diesel. As of 2008 there were 9.6 million natural gas vehicles worldwide, led by Pakistan (2.0 million), Argentina (1.7 million), Brazil (1.6 million), Iran (1.0 million), and India (650,000). The energy efficiency is generally equal to that of gasoline engines, but lower compared with modern diesel engines. Petrol vehicles converted to run on natural gas suffer because of the low compression ratio of their engines, resulting in a cropping of delivered power while running on natural gas (10%-15%). CNG-specific engines, however, use a higher compression ratio due to this fuel's higher octane number of 120–130.

Fertilizers

Natural gas is a major feedstock for the production of ammonia, via the Haber process, for use in fertilizer production.

Aviation

The advantages of liquid methane as a jet engine fuel are that it has more specific energy than the standard kerosene mixes do and that its low temperature can help cool the air which the engine compresses for greater volumetric efficiency, in effect replacing an intercooler. Alternatively, it can be used to lower the temperature of the exhaust.

Hydrogen

Natural gas can be used to produce hydrogen, with one common method being the hydrogen reformer. Hydrogen has many applications: it is a primary feedstock for the chemical industry, a hydrogenating agent, an important commodity for oil refineries, and a fuel source in hydrogen vehicles.

Other

Natural gas is also used in the manufacture of fabrics, glass, steel, plastics, paint, and other products.

Storage and Transport

Because of its low density, it is not easy to store natural gas or transport by vehicle. Natural gas pipelines are impractical across oceans.

LNG carriers transport liquefied natural gas (LNG) across oceans, while tank trucks can carry liquefied or compressed natural gas (CNG) over shorter distances. Sea transport using CNG carrier ships that are now under development may be competitive with LNG transport in specific conditions.

Gas is turned into liquid at a liquefaction plant, and is returned to gas form at regasification plant at the terminal. Shipborne regasification equipment is also used. LNG is the preferred form for long distance, high volume transportation of natural gas, whereas pipeline is preferred for transport for distances up to 4,000 km over land and approximately half that distance offshore.

CNG is transported at high pressure, typically above 200 bars. Compressors and decompression equipment are less capital intensive and may be economical in smaller unit sizes than liquefaction/regasification plants. Natural gas trucks and carriers may transport natural gas directly to end-users, or to distribution points such as pipelines.

Natural gas is used to generate electricity and heat for desalination. Similarly, some landfills that also discharge methane gases have been set up to capture the methane and generate electricity.

Natural gas is often stored underground inside depleted gas reservoirs from previous gas wells, salt domes, or in tanks as liquefied natural gas. The gas is injected in a time of low demand and extracted when demand picks up. Storage nearby end users helps to meet volatile demands, but such storage may not always be practicable.

Natural gas is a gas consisting primarily of methane, It is found associated with other hydrocarbon fuel, in coal beds, as methane, and is an important fuel source and a major feedstock for fertilizers.

Most natural gas is created by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms. Thermogenic gas is created from buried organic material.

Before natural gas can be used as a fuel, it must undergo processing to remove almost all materials other than methane. The exception to this is where systems are designed to utilise raw gas. Natural gas is often informally referred to as simply gas, especially when compared to other energy sources such as oil or coal.

CO2 emissions

Natural gas is often described as the cleanest fuel, producing less carbon dioxide per joule delivered than either coal or oil and far fewer pollutants than other hydrocarbon fuels. Natural gas itself is a greenhouse gas more potent than carbon dioxide when released into the atmosphere, although natural gas is released in much smaller quantities. However, methane is oxidized in the atmosphere, and hence natural gas has a residence lifetime in the atmosphere for approximately 12 years, compared to CO2, which is already oxidized, and has an effect for 100 to 500 years. Natural gas is mainly composed of methane, which has a radiative forcing twenty times greater than carbon dioxide. Based on such composition, a ton of methane in the atmosphere traps in as much radiation as 20 tons of carbon dioxide, but remains in the atmosphere for a 8-40 times shorter time. Carbon dioxide still receives the lion's share of attention over greenhouse gases because it is released in much larger amounts. Still, it is inevitable when natural gas is used on a large scale that some of it will leak into the atmosphere. (Coal methane not captured by coal seam gas extraction techniques is simply lost into the atmosphere; however, most methane in the atmosphere is currently from animals and bacteria, not from human's leaks.).  

Other pollutants

Natural gas produces far lower amounts of sulphur dioxide and nitrous oxides than any other hydrocarbon fuel. Carbon dioxide produced is 117,000 ppm vs 208,000 for burning coal. Carbon monoxide produced is 40 ppm vs 208 for burning coal. Nitrogen oxides produced is 92 ppm vs 457 for burning coal. Sulfur dioxide is 1 ppm vs 2,591 for burning coal. Mercury is 0 vs .016 for burning coal. Particulates are also a major contribution to global warming. Natural gas has 7ppm vs coal's 2,744ppm