As the declining of oil, coal and other fossil fuel, and the rising of environmental pollution and greenhouse's effect, natural gas, as a kind of high efficient and clean energy, has been given a great attention and favour by the countries all over the world. Natural gas liquefaction and storage technology is key to its use and development. The latest theory research shows that the construction of long distance LNG pipeline is feasible in technology and reasonable in the economy. However the researches of the liquefaction station of long distance LNG pipeline are few. The liquefaction process of the liquefaction station along the long distance LNG pipelines was discussed. Through the analysis on the reverse Carnot cycle, combined with cooling characteristics of refrigerant such as propane, ethylene, methane, liquefaction process of liquefaction station along long-distance LNG pipeline was proposed and related equipments were selected.

The strong swirl turbulent flow and the movement of drops in the cyclone separator are very complex and much more random. So it is very difficult to predict the law of flow with parse means. In order to study the condition of motion of the drops inside a stream cyclone separator of the type stairmand and it′s mechanism of separation, three-dimensional numerical simulation of internal flow field of stream phase and the motion condition of drops in it were conducted by using the software fluent. The results show that the moving tracks of small drops and big drops are different, even if their original locations are the same. The effect of the flow pulse and the toted action from big drops is very marked for the small drops, so the probability of its appearance in second flow is also much, and the effect for the capability of separation is also much. therefore， the drop is more big, the separation efficiency is more high.