DRY ICE. As a member of a large food$-$processing organization you are responsible for the cooling of perishable foods during rail transportation. Solid carbon dioxide $($Dry Ice$)$ would be a suitable cooling source, if it could be manufactured locally at a low enough price.

While contemplating this possibility during a walk through the food$-$processing plant, the gentle bubbling of the fermenters in the brewery division gives you an idea, the white plume of vapor rising from the chimney of the power plant attracts your attention, and the rotary kiln producing lime from oyster shells raises possibilities.

By the end of the day, three processes are in mind for the large$-$scale continuous production of Dry Ice. What are the flow sheets?