BOG self-circulation re-liquefaction recovery heat exchange system and method for LNG storage tank

Abstract

The invention relates to a BOG self-circulation re-liquefaction recovery heat exchange system and method. The system comprises a BOG liquefaction unit, a circulating heat exchange network and an LN2 regeneration unit, wherein the BOG liquefaction unit and the LN2 regeneration unit are connected for circulating heat exchange and regeneration through the circulating heat exchange network, and the circulating heat exchange network is an integrated composite type circulating heat exchange device formed by a multi-channel pre-cooler, a multi-channel subcooler and a multi-channel condenser in packaged and integrated modes. The system has the characteristics of compact structure, no freezing, efficient liquefaction and the like. According to the system and method, not only BOG can be re-liquefiedand recovered according to the design requirements, the cooling can also be realized through the repeated circulation of LN2, required power devices are few, the liquefaction cycle can be promoted bythe BOG through the pressure of the BOG in the early stage, in addition, an additional refrigerating machine is not needed in the circulation and regeneration processes of the LN2, so that the energyconsumption of the related devices is reduced; and the system and method have the advantages of being simple in the structure, safe, energy-saving, and capable of meeting the requirements of large-flow BOG re-liquefaction recovery.

Description

technical field [0001] The invention relates to the field of low-temperature gas liquefaction, revolves around liquefied natural gas equipment technology, and specifically relates to a BOG self-circulation reliquefaction recovery heat exchange system and method. Background technique [0002] As we all know, fossil fuels include coal, oil and natural gas. To date, coal has been the main source of energy to meet global energy needs. Coal accounts for 42% of global energy demand, compared with 21% for natural gas. However, in contrast to the high emission values ​​of coal and petroleum, natural gas is considered a clean energy source, and its combustion for power or heat can substantially reduce particulate matter, sulfur oxide (SOx) and nitrogen oxide (NOx) waste emissions, And its greenhouse gas emission is only about 40% of that of diesel fuel under the same thermal mass condition. [0003] The boiling point of natural gas is about -162°C. Through liquefaction to form liq...

AI Technical Summary

Problems solved by technology

The invention overcomes the disadvantage of low liquefaction efficiency of traditional BOG, and LN2 has no additional mechanical work input during the expansion and throttling process, and can be recycled without additional lubrication. The whole system only needs the initial LN2 pump and the terminal LNG pump as power The source promotes the cycle, which is safe and energy-saving, reduces the energy consumption of related equipment, and at the same time takes into account the characteristics of no freezing and compact structure, which meets the needs of large-flow BOG reliquefaction recovery

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