Planning to write a story. I was wondering if it was plausible that (with a decent understanding of how the thing works), if you could build a crude Bessemer converter using only technology available in the late medieval period (1300s-1400s).
A bessemer converter is a device intended to convert bulk high-carbon molten iron into steel, on the order of 5 to 30 metric tons at a time. The converter itself was a cast iron structure lined with ceramic, which would itself have been very difficult to produce in the 14th century, and even if it was possible to construct a bessemer converter, it would have been very difficult to produce sufficient quantities of high carbon iron at a sufficient temperature to load into the converter, and similarly difficult to produce a sufficient flow of high-pressure air to bubble through the liquid metal.
My feeling for this problem is that advances would have to be introduced to iron and steel manufacture along the entire iron production chain, and it would not be practical to simply introduce the bessemer converter.