LNG冷量优化集成利用技术

STUDY ON OPTIMIZATION AND INTEGRATION UTILIZATION TECHNIQUES OF LNG COLD ENERGY

我国将相继在沿海地区建成多个LNG接收站,每年将进口数以千万吨计的LNG,同时携带数着巨额冷量,而这些冷量可用于发电、空气分离、制造干冰、低温冷库等众多领域。基于国外LNG冷量利用现状,指出我国即将展开和实施此项技术还存在着:过程火用损较大,缺乏系统、全面的LNG冷量利用技术的研发指导机制,以及宏观调控力度薄弱等问题,进而提出了发展LNG冷量的集成利用方案,可为此类技术的研发利用提供新思路。以福建即将进口的LNG为例,模拟了空气分离与干冰制备的集成工艺流程,结果表明:福建每年进口的260×104tLNG可以冷却290×104t空气,相当于60000m3/h的氧气制备规模,还可以生产100×104t的干冰,其过程火用损较小;其剩余的高温位冷量可应用于低温冻结库或冰灯等项目,这对主体装置的实施效果和过程火用损的影响较小。该技术的优点在于可灵活控制冷却空气的液化率,基本不用冷却循环水,流程简单,设备投资少,能耗低等。

A number of LNG receiving stations will be built up in succession in Chinese littoral areas in recent future. And by that time China will import annually several hundreds of million tons of LNG, at the same time will bring along with great amount of cold energy, which can be used in many fields such as power-generating, air separation, carbon dioxide ice- preparation, low-temperature cold storage and so on. Based on the cold energy utilization status in quo at abroad, it is pointed out that many problems still exist in developing and carrying out this technique in present China, i. e. great fire consumption during the process, being lack of systematic and overall idea on the utilization techniques, and inability of control and regulation. Therefore it is suggested a project on optimization and integration utilization techniques of LNG cold energy, which will provide a new idea for studying the technique. Take the LNG being imported in Fujian as an example, the integration technology process of air separation and CO_2 ice was simulated. The results show that all of the refrigeration of 2.6 million tons per year LNG being imported in Fujian would cool 2.9 million tons air, which is equivalent to the scale of oxygen preparation 60000 Nm3/h, and at the same time can produce 1.0 million tons CO_2 ice. During the process, it is shown that there was less fire consumption and the remained high-temperature cold energy can be used in those projects like low-temperature cold storage or ice lanterns, which will have little influence on the action of the main service and the fire consumption during the whole process. The advantage of the technique lies in the following points such as being quite easy to control the liquefied ratio of cooling air; being unnecessary to use cooling cycling water; simple process, low-investment equipment and low energy consumption and so on.