I found those too. I think they are a heat supply for dry incense.
I tried putting incense into a smoke stack at my coal plant and it wouldn’t stay lite. the stack is 1.5 inch PVC and I used a galvi plumbing part to make a bowl, made a stop in the stack and dropped it in. It was right at the top but I don’t think it was getting enough air to burn. Before it went out it did put out a light stream of grey smoke in pine scent!
If you guys have a fix to keep the incense going let me know.
Those starlight rolls might work well.
Go see a priest. 
That is a very cool factory. What is it made of? And the bridge… with the water - what is that blue stuff? Great thread, full of surprises.