I'm not sure why a tank of ammonia would go to a lumber yard... and not really a "grain yard" (whatever that is) either.
"LPG" can mean a few different things, but commonly propane, which is used a lot for heating fuel, particularly in rural/remote locations, and often ships to dedicated distribution terminals.
Anhydrous ammonia (AA) is commonly used in nitrogen-based fertilizer production. You wouldn't really see it at a grain elevator, although some large agricultural operations handle grains and fertilizers, I'm not sure you'd see gaseous/liquified AA unless the facility produces fertilizer, not just acts as an agricultural distribution facility (fertilizer, feed, etc.).
Chlorine has lots of industrial uses, one of which is in paper mills as a bleaching agent.
Google/Wikipedia commodities of interest and look up "Uses". This can sometimes get you some ideas.
Chris van der Heide
My Algoma Central Railway Modeling Blog
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