[Gasification] Temperature of Ash Slagging (Clinker) formation(Greg Manning)

[Fredrik Ek]

Greg,

Build a rotating "knife" resting on the grate of your gasifier. With this 
technology peat briquettes have been successfully gasified in Finland. The 
point with the rotating knife is that it crushes the clinker lumps 
allowing them to pass through the grate. When you gasify peat, the ash 
always sinters if the temperature of the reactor is kept sufficiently 
high. Peat also contains about ten times more ash forming matter than wood 
does and the ash sinters at a lower temperature. The grate knife should 
not be operated constantly as this will result in great spillage of fuel 
or even total loss of the char bed. The grate scraper should be operated 
on an as needed basis, with a the help of a timer -or in order to minimize 
the spillage of char- when the pressure drop over the reactor starts to 
increase.

The ashes from a peat downdraft gasifier can look and feel like black 
gravel when you remove it from below the grate.

Fredrik

Citerar Greg Manning <a31ford at inetlink.ca>:

> 
>  Greetings Gero, and list.
> 
>  Yes I agree at the reduction level, one needs very high temperatures to
> crack tars, however, what I'm getting is clinker forming in the "air arc"
> at
> about 4cm away form the front of the tuyeres these are not huge, rather
> about the size of grass seed. Very consistently down through the arc to
> the
> top of the grate, they pass as long as they stay small. The problem is
> that
> this only happens at the upper-most gas production level, and if by
> accident
> I go over this amount, the clinker forms large enough that it will not
> pass
> through the grate, and therefore will cause the gasifier to eventually
> plug-up 6-10 hours later in operation.
> 
> My goal is to set a "High point" for gas production on a specific sized
> gasifier, so down time for cooling, disassembly and cleaning is avoided.
> 
> Or put another way... the problem is not the gasifier, rather it's my
> finding the top end of gas production, without having to consume another
> 10
> hours of feedstock to figure out that I accidentally went over the
> top.....
> 
> Greg
>