That looked like 2 separate explosions. The first looked more like a chemical release of some type, while the second explosion looked more like a gaseous explosion (instant firearm spread out as it burned all,the escaping gas) which then lit the chemicals on fire too. Was that a natural gas or propane tank sitting behind whatever exploded first?
Maybe it was a BLEVE, boiling liquid, evaporating vapor, explosion? Liquid doesn’t actually burn it has to turn into a vapor, which happens at vastly different ambient temperatures.
I think it’s propane. The column of fire is from a pressure relief valve. As the liquid burns off, gas occupies more volume inside and the tank begins to heat up more, then it weakens, distorts, and ruptures.
Not sure...probably a demonstration for fire professionals.