for some reason when molten glass drops into the brine the brine just dissapears instead of becoming steam and salt

The glass doesn't disappear. It merges to the pile of glass debris that's already down there

 

The issue isn't glass disappearing , the issue is that the brine disappears into nothing instead of turning into steam and salt

 

Edited November 19 by wiwestor

oops! I read that wrong. Molten glass does delete liquids it's dropped on even on smaller puddles. I wouldn't expect the molten glass to heat up water based liquids and instantly boil them but the liquid should be displaced instead of deleted. Even if you change the build to work around the issue (eg. making a pit with metal tiles where the molten glass drops and have saltwater around it), molten glass will still not be able to heat saltwater much