Joule Thomson
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What is the Joule Thomson effect?

The Joule Thomson effect or "JT" effect, refers to the temperature of a gas that falls when it expands without doing any work (e.g. gas at constant pressure through a small orifice).

What is a "JT Plant?"

JT Plants, or "Joule-Thomson" plants operate as a gas processing plant in that the JT Plant operates through a natural gas pressure differential causing the temperature to fall significantly, thereby making the natural gas liquids (propane, butane, and natural gasoline) within the natural gas stream, to "condense" and fall out of the natural gas stream.

JT plants condense the heavier natural gas liquids from the natural gas stream to meet that specific natural gas pipeline's "pipeline quality gas" specifications thereby making the natural gas saleable to downstream end-users/customers. The natural gas liquids that are produced from the JT plant are stored in tanks for eventual sale as propane, butane and natural gasoline.

An amine unit - also referred to as an "amine plant," is used for "gas sweetening" in the "gas processing" sector of the Midstream Oil and Gas sector.

Amine units provide H2S removal as well as CO2 removal from natural gas and liquid hydrocarbons. The process involves both absorption and chemical reactions.

What is LNG Liquefaction?

LNG Liquefaction is a process that refrigerates Natural Gas until it is condensed into a liquid at close to atmospheric pressure (maximum transport pressure set at around 25 kPa/3.6 psi) by the natural gas to approximately −162 °C (−260 °F) which reduces its volume to 1/600th or its original volume for ease of transportation.

Liquefied Natural Gas or simply "LNG" is natural gas which is primarily methane or CH4 that has been liquefied to reduce its volume. As previously stated, LNG is colorless, odorless, non-toxic and non-corrosive. LNG hazards include flammability, freezing and asphyxia.

The LNG Liquefaction takes place at an LNG terminal, typically located at an ocean port where one or more natural gas pipelines deliver natural gas. The natural gas has had the contaminants removed by gas processing and purification, which removes, condensates such as water, dust, helium, mud, oil, CO2, H2S and mercury. The natural gas is then cooled down in stages until it is finally liquefied at -160 degrees C. The Liquefied Natural Gas is stored in cryogenic storage tanks and loaded onto an LNG ship and shipped.

LNG Liquefaction plant

What is "NGL Fractionation"?

NGL, or natural gas liquids fractionation plants purpose is to separate the mixed natural gas liquids stream into separated products. These natural gas liquids that are separated by heat at NGL Fractionation plants include; ethane, propane, normal butane, isobutane and natural gasoline.

What is NGL Recovery?

Toward the end of the gas processing process and natural gas treating process, wherein the "raw" natural gas (methane or CH4) is readied for sale as "pipeline quality gas," the recovery of the valuable natural gas liquids (NGL) takes place. In many gas processing facilities, a cryogenic plant - which provides low-temperature distillation that recovers the natural gas liquids. The residue gas from the NGL recovery process, is the purified pipeline quality gas that is sold via pipeline and sent so end-users such as LDCs (local distribution companies - or natural gas utility) for distribution via natural gas mains in their cities and markets.

Other NGL recovery methods include an NGL fractionation "train" which typically consists of three distillation towers in a series. The series occurs in the following order:

1. deethanizer
2. depropanizer
3. debutanizer.

The overhead product from the deethanizer is ethane - after which the bottoms flow to the depropanizer. The overhead product from the depropanizer is propane and the bottoms then flow to the debutanizer. The overhead product from the debutanizer is a mixture of normal butane and iso-butane. The bottoms products are a C5+ mixture. Most cryogenic plants, however, do not include fractionation due to economic reasons. Therefore the NGL stream is then transported as a mixed product to separate, standalone fractionation plants that are located near refineries or chemical plants that need these NGLs feedstock.