Here are a couple statements from articles on-line:
"When natural gas burns, a high-temperature blue flame is produced and complete combustion takes place producing only water vapor and carbon dioxide."
"Freeze-ups can happen. Pipelines freeze up, because of MOISTURE in the gas. Frozen equipment, power plants – STOP, just like that! We see the devastation that this caused in Texas
this week and is still occurring. In Texas, a warm climate, freeze-ups are not something that come to mind to worry about. However, look how quickly and how easily it can happen.
Natural gas comes out of the ground saturated with moisture. That moisture needs to be removed or it will cause problems. If the moisture is not removed, it will corrode burners, burn less efficiently, and in cold weather, the moisture will freeze and block the flow of gas."
When my NG furnace is functioning, it, the same as the A/C, removes the water from the gas during the combustion. I have icicles forming on the outside exhaust pipe - reaching the ground, as well as being collected in a furnace-mounted reservoir inside, which is pumped to the floor drain.