关于液氩气生产及精制设施设计
Introduction
Cryogenic liquefied natural gas (LNG) is a refrigerated liquid produced by cooling natural gas to -162 oC. When methane is cooled toconvert it to LNG, other components with a lower boiling point, such as ethane, propane and butane, are also converted to LNG. The process of converting natural gas to LNG is known as cryogenic processing, and the facility in which cryogenic processing occurs is referred to as a cryogenic liquefaction plant.
Design Aspects
The purpose of the cryogenic liquefaction plant is to cool natural gas to a temperature low enough for it to condense and become a liquid. The cryogenic liquefaction process involves a series of steps that must be completed in order to successfully produce LNG. The steps include cooling the feedgas, filtering impurities from the feedgas, flashing the feedgas to produce vapor and liquid compounds, separating the vapor phases from the liquefied phases, compressing the vapor phases to provide the power to drive the process, and finally, liquefying the liquid phases.
Each step in the process requires certain components and equipment. Components may include pumps, compressors, heat exchangers, separators, condensers, and tanks. Additionally, other supporting systems must be included to aid in the operation of the plant, such as an auxiliary power plant, skids, instrumentation, data acquisition, and control and safety systems.
Process Equipment
The equipment used in a cryogenic liquefaction plant is designed to operate safely, reliably and efficiently. This includes the selection of materials for items such as piping, vessels, tanks, and pumps. The selection of the appropriate equipment for each process step is a critical factor in obtaining optimal plant performance.
Pumps are a vital piece of process equipment and are used to move cryogenic liquids from one part of the process system to another. The selection of pumps is based on the flow requirements of the system and the pressure requirements at each point in the process.
Compressors are also used in the process and are responsible for providing the power to drive the process. Compressors typically use either screw drive or centrifugal technology. The selection of a compressor is based on its efficiency, power consumption, and pressure requirements.
Heat exchangers are used in the process to transfer heat from one medium to another. Heat exchangers are rated according to the amount of heat they can transfer. The selection of a heat exchanger is determined by the cooling and heating demands of the process.
Storage Equipment
The process of cryogenic liquefaction results in the formation of highly pressurized, cryogenic liquids. The storage equipment used for cryogenic liquefied natural gas is designed to accommodate these unique properties. The storage tanks used for cryogenic liquefied natural gas must be designed to withstand the extreme temperatures and pressures of the cryogenic liquids. The tanks are typically constructed of high-strength, heat-treated steels that can withstand these extreme conditions.
Conclusion
Cryogenic liquefaction is an important process used in the production of liquefied natural gas. The design of a cryogenic liquefaction plant and the selection of the appropriate process and storage equipment are critical factors in obtaining optimal performance. The design of the cryogenic liquefaction plant must account for the specific requirements of the process, and the selection of process and storage equipment must be based on the requirements of the process. The components used in the process must be capable of operating safely, reliably, and efficiently.
