In the form of liquefied natural gas (LNG) is colorless liquid without color and smell, 75-90% consists of methane and has very important properties: as a liquid it is non-flammable, not poisonous and not aggressive, which is very important during transportation. The liquefaction process of LNG is stepwise, where each new step means a compression of 5-12 times, followed by cooling and transition to the next stage. LNG becomes liquid after the final stage of compression.
Liquefaction of gasand is very energy-intensive process, which takes up a quarter of the energy contained in a given volume of gas. For the liquefaction of gasand used several types of plants – turbine-vortex, throttle, turbo-expander, and others. Sometimes the liquefaction is produced by the combined scheme, which includes elements of the above cycles. As practice shows, the greater simplicity and reliability of different throttle setup.
The development of modern technologies contributes to the fact that liquefaction of natural gasand is made possible in terms of specialized mini-mills. This is especially true for Russia – a country with a developed network of main gasof provodov, aided by the presence of numerous large and small gasRaspredelitelnaya stations and automotive gasstations napolnitelya. On this basis it is very profitable to build mini-LNG plants.
Installation for production of liquefied natural gasand consists of purification from water vapor and carbon dioxide, block liquefaction system control and automation, cryogenic capacitive equipment for storage and LNG, and compressor equipment. When choosing the place of installation of the mini-plant must be taken into account the characteristics of the equipment, the availability of utilities – electricity, water, telephone and gasthe new highway, safe distances from the object, expensive and driveways.
Advice 2: How to obtain liquefied natural gas
Liquefied natural gas demand in various fields of human activity - in industry, in automotive industry, in medicine, in agriculture, in science, etc. Considerable popularity liquefied gass won due to ease of use and transportation, as well as ecological purity and low cost.
Before liquefaction of the hydrocarbon gasand it is necessary to pre-clean and remove water vapor. Carbon dioxide gas is removed using a three-stage molecular filter. The thus purified natural gas in small quantities is used as a regeneration. The recovered gas is either flared or used to generate electricity in power generators.
Drying occurs with the help of 3 molecular sieves. One filter absorbs water vapor. Another dry gas, which is then heated and passes through the third filter. To lower the temperature of the gas is passed through a water cooler.
After cleaning and drying natural gasand starts the process of liquefaction, which is carried out sequentially in stages. Natural gas at every stage of liquefaction is sealed from 5 to 12 times, then cooled and transferred to another stage. At the completion of the last stage of compression with cooling is actually liquefaction of natural gas. The volume is reduced approximately 600 times.
To receive liquefied natural gas in several ways: replacement, nitric way, mixed, etc. While replacement method at GDS receive liquefied natural gas, using the energy of the pressure drop. The advantages of this method include low energy consumption and investment. But the downside is the low efficiency of liquefaction, the dependence of stable pressure, inflexible production.
Nitrogen method involves the production of liquefied petroleum gasand any gasoriented sources. The advantages of this method include simplicity of technology, high security, flexibility, ease and low cost of operation. Limitations of this method is the need of source of electricity and high capital costs.
In the mixed mode of production of liquefied natural gasas refrigerant, a mixture of nitrogen and methane. Get gas from any sources. This method is flexible production cycle and small variable costs of production. When compared with nitrogen liquefaction method, here the capital costs are more significant. Also need a source of electricity.