LNGprocessdescription工序描述Overall Material Balance总物料平衡英译中分享并...

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Overall Material Balance

The design composition assumes that the feed gas enters the facility with no bulk liquids present. An inlet separator is provided, however, to protect the plant from small liquid slugs.  The current design basis assumes a 7.6 in (25 ft) slug from the feed gas pipeline. Gas from this inlet separator flows to an amine unit where CO is removed to a specification of less than 50 ppmv. After CO removal, the gas is dehydrated in a two- bed molecular  sieve unit.   The dry CO -free gas is then ready for liquefaction.   The refrigerant  exchanger is

contained in a single cold box assembly.Heavy hydrocarbon removal from the natural gas stream  is  integrated  into the  liquefaction  process.  The heavy hydrocarbon liquid is vaporized, mixed with the boil-off gas stream, compressed, and utilized for fuel. The LNG is sent to storage below deck to any of the three cargo tanks, and a compression system is included to handle the flash gas from LNG letdown, boil off gas, and loading vapors. A portion of the gas from this system is used for molecular sieve regeneration and then used as fuel for the refrigeration compressor gas turbine.  The remaining part of the boil-off gas stream is sent back to the cold box to be reliquefied into LNG.

Heat for the various users is provided by a heat medium system. This system recovers heat from the refrigeration turbine  exhaust to satisfy all the process heat requirements.  Cooling is provided by a closed- loop, fresh water cooling system.

总物料平衡

设计成分是假设原料气进入加工设施没有以bulk liquids散装晶体块侵入的。所以设计安装inlet separator进气分离器的用途就是保护加工站防止小型晶体块侵入。目前的设计是基于假设原料小型晶体块侵入位置为7.6米（25英尺）。经过进气分离器 的气体流进胺系统amine unit，在此装置里，二氧化碳将会根据规范去除至低于50ppmv(COMMENT:BEDD表示20ppmv)。二氧化碳去除之后，此时的气体脱水至two bed molecular sieve unit双床分子筛规。干燥无二氧化碳的气体此时处于待液化状态。制冷交换器安装在一个single cold box assembly单体冷箱总成内。

从天然气流里去除的重烃完整地进入液化处理。此重烃液体是蒸发后的，混合着蒸发气流，压缩过，并且当做燃料使用。LNG将被输送至甲板下方的三个液舱中的任何一个，此处包含的压缩系统用于处理flash gas闪发气体来自于：LNG压力骤低letdown，蒸发气体BOG和油蒸气进入loading vapors。此系统里的部分气体将会用于分子筛再生，之后作为燃料供给制冷压缩机气轮机refrigeration compressor gas turbine。蒸发气流剩余部分将返还到冷箱再液化成LNG。

热媒系统heat medium system提供给多种用户所需热量。此系统从制冷轮机排放再生热量满足所有加工所需热量。冷却是由一个闭合环路的淡水冷却系统提供。