Natural gas is found by drilling into the earth's crust where pockets were trapped thousands of years ago. Once the gas is brought to the surface, it must be processed to remove impurities such as liquids (water, heavier hydrocarbons), sand, other gasses like carbon dioxide, hydrogen sulfide, butane, propane, ethane, etc. The removal of these impurities occurs in what is known as the Gas Processing Industry using various techniques to produce what we know as Natural Gas. The final product is transported throughout the country using large pipelines to large industry, small businesses, and residential customers.

Initial Stages - Physical Separation

The Natural Gas processing industry begins with the separation of the bulk liquids from the gas streams. While the devices that perform these tasks can get complicated they all work on basic principles. Generally th

Glycols will absorb water when brought in contact with a gas stream using an absorber column. Also glycols are easily regenerated using simple distillation where a heat source raises the temperature reducing the solubility that results in liberating the water from the glycol. Once this occurs the water can be separated and the glycol can be recycled to the contractor to absorb more water.

The resultant acid gas stream that is generated in an amine plant must be further processed to convert the H2S into Brimstone or Sulfur. This typically occurs in a Sulfur Recovery Unit using a Claus Process. The Claus process involves two reactions where first air and H2S are combusted in a furnace creating Sulfur Dioxide (SO2) and water. With the heat generated by the combustion reaction the Claus reaction between H2S and SO2 forms sulfur and water.

Sour gas processing involves a number of different techniques but the bulk of the industry utilizes aqueous alkanolamine technology or amine sweetening processes to remove sulfur compounds and carbon dioxide. This process involves contacting an amine solvent with the gas stream in a trayed vessel known as a contactor that chemically reacts with the H2S and CO2 but not with hydrocarbons. The amine is a weak base and the H2S & CO2 are acids in the presences of water and the resultant is an amine salt commonly referred to as rich amine. The rich amine exits the contractor as a liquid and sweet hydrocarbons exit as a gas stream. The rich amine is carried into a regenerator where it is heated causing the H2S and CO2 to be liberated as a gas from the amine. The liquid and gas are again separated and the amine is recycled to the contractor while the H2S and CO2 are sent downstream to be processed further.

Today cryogenic technology has replaced the lean oil technologies and offers much greater NGL recovery for a lower investment. In physics cryogenics generally deal with temperatures of -150oF and lower, yet the cryogenics of natural gas processing deals with temperatures of -50oF and below. The key feature of this process is its turboexpander-compressor. This device takes a large pressure drop across expander blades that are on a shaft that drives a compressor that is mounted on the opposite end. This serves to transfer energy causing the temperature and pressure of the stream that is being expanded to drop and the temperature and pressure of the stream being compressed to rise. As a result of the drastic temperature drop across the expander the ethane and heavier hydrocarbon components condense along with some of the methane. This stream is sent to a demethanizer column where the methane is driven out of the condensed hydrocarbons due to energy in the form of heat being applied to the bottom of the column. The gas stream that exits the top of the column is recompressed in the compressor, driven by the expander, and sent to market. Intertwined in the process are points where heat exchange between gas streams occurs to minimize the overall energy input into the process

Due to the co absorption of the methane into the oil a rejection system is necessary to get rid of the methane that cann

Some common words found in the essay are:
Water Removal, Liquids NGL, Natural Gas, Demethanizer ROD, Sulfur Carbon, Gulf Coast, Unfortunately Claus, H2S CO2, Introduction Natural, Processing Hydrocarbons, gas stream, natural gas, lean oil, gas processing, gas streams, carbon dioxide, h2s co2, heavier hydrocarbons, fixed bed, stream exits, gas stream cooled, gas processing industry, ethane propane etc, water gas stream, exits top column,
Approximate Word count = 2130
Approximate Pages = 9 (250 words per page double spaced)