Technology & Engineering
Liquefaction of Gases
Liquefaction of gases is the process of cooling and compressing a gas to transform it into a liquid state. This is achieved by reducing the temperature and increasing the pressure of the gas, causing its molecules to come closer together and form a liquid. Liquefied gases are commonly used in various industrial and scientific applications, such as in refrigeration and cryogenics.
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eBook - PDFThe Mechanical Universe
Mechanics and Heat, Advanced Edition
- Steven C. Frautschi, Richard P. Olenick, Tom M. Apostol, David L. Goodstein(Authors)
- 2008(Publication Date)
- Cambridge University Press(Publisher)
Otherwise, skiing on snow would be like skiing on concrete. 22.4 Liquefaction of Gases At the turn of the nineteenth century, a handful of scientists may have understood the phases of water, but even fewer saw a generalization to the states of matter. The idea crystalized through research into the Liquefaction of Gases. Earlier a Dutch scientist, Martin Van Marum, had accidentally liquefied ammonia gas under pressure while using it to test Boyle's law; however, he didn't grasp the significance of this first liquefaction. Until 1823, the Liquefaction of Gases remained tenuous. 554 THE QUEST FOR LOW TEMPERATURE In that year, at the Royal Institution of London, a young chemist made an explosive discovery. While heating a compound in a sealed glass tube, Michael Faraday produced an oily-looking substance. When he filed the tube open to investigate the substance, the tube promptly exploded. But Faraday realized that he had liquefied chlorine gas. This great intuitive genius of the nineteenth century would later become famous for his researches in electro magnetism, but he revealed his talents in this early episode. Unlike Van Marum, Faraday understood perfectly the significance of his discovery, and immediately undertook a quest to liquefy other gases. Using an inverted U tube of glass, in one leg of which he could heat reagents to evolve the gas in question, while the other leg, under pressure, could be cooled, if necessary, to form the condenser, he succeeded in liquefying many gases. With that success, Faraday reached the plausible conchision that all forms of matter could exist in each of the fundamental states, given the right conditions of temperature and pressure. The next great advance in understanding the states of matter came in 1835 when the French scientist Thilorier managed to solidify carbon dioxide (CO 2 ). The phase diagram of carbon dioxide is shown in Fig.
eBook - ePub- Saeid Mokhatab, John Y. Mak, Jaleel V. Valappil, David Wood, David A. Wood(Authors)
- 2013(Publication Date)
- Gulf Professional Publishing(Publisher)
The natural gas liquefaction process is the key component in LNG plants in terms of cost, complexity, and operational importance. A good understanding of design and operational requirements and efficiencies of natural gas liquefaction systems is essential for the success of the gas liquefaction plant. There are several licensed natural gas liquefaction processes available with varying degrees of complexities and experience. The thermal efficiency and capital cost for the various licensed processes are competitive and the differences are typically small with respect to thermodynamics and cost. The real keys in developing a successful liquefaction plant are equipment selection and its configurations to meet a plant’s capacity goals.This chapter provides a critical overview of the process technology options available for the liquefaction of natural gas, and discusses the factors that should be considered by project developers in order to select the most appropriate process for their situation.3.2 Natural gas liquefaction technology
3.2.1 Liquefaction background
Liquefaction technologies are based on refrigeration cycles, which take warm, pretreated feed gas and cools and condenses it to cryogenic temperatures into a liquid product. The refrigerant may be part of the natural gas feed (open-cycle process) or a separate fluid continuously recirculated through the liquefier or heat exchanger (closed-cycle process). To achieve the extremely cold or cryogenic temperatures required to produce LNG, work must be put into the refrigerant cycle(s) through a refrigerant compressor(s), and heat must be rejected from the cycle(s) through air or water coolers. A number of natural gas liquefaction processes have been developed over the last five decades based upon this fundamental principle.Besides seeking to reduce unit investment and operating costs, the primary objectives of these technological innovations are to increase the volume of LNG production gas and optimize the efficiency of the refrigeration process employed. In theory, the most thermodynamically efficient liquefaction process is one with a refrigerant or a mixed refrigerant system that can duplicate the shape of the natural gas cooling curve at operating pressure (see Figure 3-1
- Karan Sotoodeh(Author)
- 2022(Publication Date)
- Gulf Professional Publishing(Publisher)
2 ), Helium (HE) can be liquefied in various freezing and cryogenic temperature ranges. The focus of this chapter is on LNG technology, including its history, value chains, processing, transportation, and more.2.1.1: Introduction to LNG
LNG is a type of liquefied gas, meaning that LNGs are components of natural gas that are separated from the gas as liquids. More specifically, an LNG is a natural gas that has been processed to remove valuable elements and compounds such as helium and impurities like carbon dioxide and hydrogen sulfide and then condensed into liquid by cooling. An LNG is made predominately of methane (CH4 ) with some mixture of ethane (C2 H6 ) and other trace compounds. Table 2.1 shows the chemical composition and other physical properties of a standard LNG.Table 2.1 LNG composition.LNG chemical composition and physical properties Mole fraction and other values Methane (CH4 ) 89.63% Ethane (C2 H6 ) 6.32% Propane (C3 H8 ) 2.16% Isobutane (C4 H10 ) 0.0% n-Butane (C4 H10 ) 1.20% Isopentane (C5 H12 ) 0.0% n-Pentane (C5 H12 ) 0.0% Nitrogen (N2 ) 0.69% Average mole weight (gr) 18.12 Boiling point at atmospheric pressure (°C) − 160.9 Density kgm 3459.4 LNG is an odorless, colorless, non-toxic and non-corrosive compound. Its main advantages are that it is considered a clean and environmentally friendly source of energy. In fact, LNG offers as much energy as petrol and diesel fuels with less pollution. No environmental cleanup is required for an LNG spill in the water or on the land. The hazards associated with LNG are freezing (extreme low temperature) and the flammability of its vapors. Exposure to LNG or direct contact with can damage skin tissue regarding LNG cryogenic temperature. The effect of cryogenic fluid on the skin is the same as a thermal burn. More precisely, it causes frostbite, a type of injury caused by the freezing of skin. First the skin becomes very cold and red and then it goes numb. As for LNG's flammability, it is important that LNG is not ignited until it becomes a vapor as it is not flammable and explosive in its liquid state. It is important to know that LNG has a tendency to vaporize, which has a big impact on LNG's supply chain from safety, technical, and economic points of view. Spillage of LNG in water can generate vapor through a hazardous process called rapid phase transition (RPT). The mixing of LNG vapor with air can also ignite a fire. Critically, LNG ignition occurs when the ratio of LNG to air is between 5% and 15%. This means that a concentration of less than 5% LNG vapor in the air is not sufficient for ignition and that a concentration of more than 15% LNG vapor in the air will not ignite due to a lack of oxygen. LNG does not have a common price denominator as does oil, such as Brent oil or West Texas Intermediate (WTI). LNG is priced according to its heating value, and the heating value of LNG varies depending on the heating value of heavy hydrocarbons such as ethane and propane. The established heating value is different from one market to another one and in various countries. As an example, the established heating value of LNG in Japan is between 1120 and 1150 BTU per ft3 . This value is different in European LNG markets and is in the range of 990 to 1070 BTU per ft3
No longer available |Learn more- (Author)
- 2014(Publication Date)
- The English Press(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter- 5 Liquefied Natural Gas Liquefied natural gas or LNG is natural gas (predominantly methane, CH 4 ) that has been converted temporarily to liquid form for ease of storage or transport. Liquefied natural gas takes up about 1/600th the volume of natural gas in the gaseous state. It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability, freezing and asphyxia. A typical LNG process. The gas is first extracted and transported to a processing plant where it is purified by removing any condensates such as water, oil, mud, as well as other ____________________ WORLD TECHNOLOGIES ____________________ gases like CO 2 and H 2 S and some times solids as mercury. The gas is then cooled down in stages until it is liquefied. LNG is finally stored in storage tanks and can be loaded and shipped. The liquefication process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid at close to atmospheric pressure (maximum transport pressure set at around 25 kPa/3.6 psi) by cooling it to approximately −162 °C (−260 °F). The reduction in volume makes it much more cost efficient to transport over long distances where pipelines do not exist. Where moving natural gas by pipelines is not possible or economical, it can be transported by specially designed cryogenic sea vessels (LNG carriers) or cryogenic road tankers. The energy density of LNG is 60% of that of diesel fuel. Basic facts LNG is principally used for transporting natural gas to markets, where it is regasified and distributed as pipeline natural gas. LNG offers an energy density comparable to Gasoline and diesel fuels and produces less pollution, but its relatively high cost of production and the need to store it in expensive cryogenic tanks have prevented its widespread use in commercial applications.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter-13 Liquefied Natural Gas Liquefied natural gas or LNG is natural gas (predominantly methane, CH 4 ) that has been converted temporarily to liquid form for ease of storage or transport. Liquefied natural gas takes up about 1/600th the volume of natural gas in the gaseous state. It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability, freezing and asphyxia. A typical LNG process. The gas is first extracted and transported to a processing plant where it is purified by removing any condensates such as water, oil, mud, as well as other gases like CO 2 and H 2 S and some times solids as mercury. The gas is then cooled down ____________________ WORLD TECHNOLOGIES ____________________ in stages until it is liquefied. LNG is finally stored in storage tanks and can be loaded and shipped. The liquefication process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid at close to atmospheric pressure (maximum transport pressure set at around 25 kPa/3.6 psi) by cooling it to approximately −162 °C (−260 °F). The reduction in volume makes it much more cost efficient to transport over long distances where pipelines do not exist. Where moving natural gas by pipelines is not possible or economical, it can be transported by specially designed cryogenic sea vessels (LNG carriers) or cryogenic road tankers. The energy density of LNG is 60% of that of diesel fuel. Basic facts LNG is principally used for transporting natural gas to markets, where it is regasified and distributed as pipeline natural gas. LNG offers an energy density comparable to Gasoline and diesel fuels and produces less pollution, but its relatively high cost of production and the need to store it in expensive cryogenic tanks have prevented its widespread use in commercial applications.
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