STUDY ON OPTIMIZATION AND INTEGRATION UTILIZATION TECHNIQUES OF LNG COLD ENERGY

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.