Aerts, Parker et al:

I found the following on my laptop three weeks after I got home, probably
written in the Tokyo airport during my "extra" Saturday, courtesy of the
dateline.. If I sent it before, please excuse!

On my trip I saw a monstrous pressurized recirculating fluidized bed combustor
in Finland. It was impressive as a major engineering feat. One justification
is that the hot gas filtering with ceramic candles are relatively cheaper at
high pressure. However, the cost of the equipment is very high for combustion.

Pressurized operation MAY be justified for gasification, where operation of a
combined cycle gas turbine is the prize or for making synthesis gas where direct
production of methanol or ammonia is the prize. I visited the 5MWe, 9MWh
recirculating fluidized bed at Varnamo last month; they had operated the whole
system successfullly the previous week for a whole week. The system used lock
hoppers, but they were interested in trying a plug feeder which greatly reduces
gas losses.

So, I am glad to see pressurized operation being tested, but hope it is not
necessary for combustion.

Yours, TOM REED