These files are often referred to by Doug Williams in exchanges in the Gasification mailing list and the Biomas mailing list to which he belonged to. Doug was the Managing Director of Fluidyne Gasification.
All the files can be downloaded by right-clicking them and selecting "Save target as". The diagram files are in standard jpg and gif format, and the specifications are Adobe PDF files produced using OpenOffice.org
Doug passed away in July 2019
has written a nice write up on his website - http://nznano.blogspot.com/2019/07/doug-williams-pillar-of-gasification.html