What is the ice on the satana natural gas pressure cut of Shanghai Volkswagen?

This is the gas tank of LNG heavy truck.

These two tanks are filled with compressed natural gas. The jar is a double-layer sealed explosion-proof structure. According to the picture, it is estimated that each can is 750L, and the capacity is 1500L, which is not small.

In order to load more LNG, the pressure of these two tanks is very high, usually less than or equal to 1.72Mpa, and in extreme cases it reaches 2.4Mpa (the threshold of the opening pressure of the second-stage relief valve), but the LNG engine does not need such a high pressure, so in order to be suitable for gas premixing, it is necessary to set two-stage decompression between the gas tank and the intake pipe. Every decompression is to change the state from liquid to gas, that is, to gas. When the fluid changes from liquid to gas, it needs to absorb heat to maintain the active state of molecules. Therefore, if there is continuous large-flow gas transmission, condensed water, fog or ice will appear on the wall of the pipeline with fast flow rate.