Using biochar setups to convert shells to lime?

Are there any setups that have been designed for making biochar that could be used with egg shells, sea shells or limestone to make calcium oxide? I love the idea of converting my chicken egg shells to slaked lime and then using it to preserve fresh eggs. Not to mention all the other boss things you can do with it. I wasn't sure where to post this question so if you have a suggestion for a better place to post it let me know.

Here are my inspiration vids:
https://www.youtube.com/watch?v=jOxaOTUGuKo
https://www.youtube.com/watch?v=yUYgguMz1qI

I make small batches of biochar in my wood fire in stainless steel steam table pans. Sometimes I fill one with shells, crushed limestone or bones instead of wood chips and nut shells. The temperature inside my fire is around 600 C when it's got a lot of coals in there, so that will definitely calcine the feedstock and I get decent quicklime or bone char as an end product.