How does an natural gas dehydration plant work?

compressing the gas makes the water turn to liquid 

This treatment consists of dehydrating the natural gas, which is accomplished by lowering the dew point temperature of the gas at which water vapor will condense from the gas.

Too complicated for Gardening, but basically raw natural gas from a well is a mixture of various volatile hydrocarbon gases and liquids.  A dehydration plant uses a series of tall towers, each with different processes to separate the various components of the gas.  The processes involve treating the gas with chemicals such as amine and glycol as well as refrigeration as methods of separation.  The end product is basically methane.