I may have asked this before, but a quick review of my stats turned up nothing relevant. Anyway, on to the quesion:
Supposedly when making smokeless powder or guncotton (which are similar but not identical compounds as I understand it) you get a chain reaction (with clouds of toxic gas) if you try to make too much in a single batch (i.e. more than a few tablespoons worth).
So, how the heck they make this stuff safely on an industrial scale?
I think you are misinformed about the toxic gas thing. I’ve walked on catwalks above giant vats with 25,000 gallons of gun-cotton being produced (nitric acid and cotton linters being mixed). No toxic gas. A good source for the production of propellants is TM 9-1300-214 available in pdf from many sources (free) on the web. Radford Army Ammunition Plant in Virginia makes huge quantities on an industrial scale.
Now production of the nitroglycerin to make the double base and triple base propellants - is a different story. About once a decade, the NG building/plant disappears - now a remote operation.
You’re probably right in that I’m misinformed or misunderstanding something about the production process, however I have seen a few videos were a person making guncotton gets clouds of red gas simply from increasing the scale of the process.
For example, in the Mythbusters episode “Exploding Trousers” Carrie dipped a 3" square of denim in a solution and stirred it around for several seconds with no ill effects. However, when she put an entire pair of jeans (of the same sort the denim patch had been cut from) in a container and added the solution it quickly began producing large red clouds of smoke and seemed to dissolve (fizzing around material which then looked like it was melting or being reduced in size). A few seconds later, we see that large swath of denim (that used to be a pair of jeans) as a solid cube sitting in a bowl of water with a wooden spoon sticking straight up in the middle of it).
In another video (I’d provide the link, if I could find it again) we see a person mixing 3 cotton balls/pellets in a (small container of) solution with no ill effects. However, when he adds 5+ we see the red smoke until he dumps the whole thing in a large container of water (or whichever order allows you to safely mix acid and water).
Industrial chemical engineering usually involves the precise control of chemical and physical conditions. I can’t find any guides to the industrial production of guncotton/nitrocellulose, but I would expect that involves high quality raw materials that do not contain trace impurities (it appears that trace metal impurities may be responsible for catalysing the runaway reaction), controlled mixing, and management of the reaction temperature/pressure. All these things are part of the process of turning a reaction you can do in a testtube into one you can use for large-scale commercial production.
Your best bet for precise details would be a Chemical Engineering Manual.