A pyrolysis chamber for the extraction of combustible gasses from biomass waste such as wood chips has a gravity fed chamber, where fuel passes, in succession, through a pre-heating zone, an oxidation and reduction zone, a gas outlet zone and a solids offloading zone. By modulizing a conventional power adaptor and combining it with a port connection device, the modulized power adaptor is fabricated to resolve the problem of messy connection lines resulted from using or carrying such as a notebook computer. The disclosed embodiment of the nut includes a counterbore through the end face and radial channel-shaped feed grooves and the feed pawl includes a cylindrical center portion and radial portions received in the counterbore and feed grooves.