[Stoves] the 150 gasifier in operation in Vietnam (Matt Redmond)

[rongretlarson at comcast.net]

Paul, Matt, list: 

I like your (earlier) idea of a ceramic "strainer". You might want to start by doing more googling on the topic of "ceramic foam" - which seems to be a relatively new sub-discipline of the ceramic industry. The "foam" companies seem to be able to produce a material which can serve as a strainer (open cell structure, not closed) - which will allow the hot gases to flow through the foam. 

Here is one example of a group explaining this sort of work: 
http://www.madehow.com/Volume-5/Ceramic-Filter.html#b 

There are plenty of companies doing this "foam" work - to be found via googling. 

Following Matt's suggestions below, there may be a place also for "rock wool" - vs glass fiber (to get higher temp capability. 

If you use metal (as below), I think a thin ceramic coating might help on longevity, if the coating is thin enough. Will be hard to match coefficients of thermal expansion, but may be possible . 

Ron 

----- Original Message -----
From: "Paul Olivier" <paul.olivier at esrla.com> 
To: mredmond3 at gatech.edu 
Cc: "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org> 
Sent: Thursday, March 8, 2012 4:54:46 PM 
Subject: Re: [Stoves] the 150 gasifier in operation in Vietnam (Matt Redmond) 

Matt, 

One way to solve the problem of what material to use in a wire mesh dome 
is to view the wire mesh as a disposable item that might last but a few months. 
I found an easy way to insert a 304 stainless steel wire mesh disk (30 mesh) into a rigid receiving structure that is dome-shaped. 
When a flat wire mesh disk is pushed into the shape of a dome, it exerts a lot of pressure against the receiving structure. 
Nothing has to be welded. 
When it wears out, it is pulled out, and another disk is put in its place. 

Thanks. 
Paul 


On Wed, Mar 7, 2012 at 7:44 PM, Matthew Redmond < mredmond3 at gatech.edu > wrote: 


Ron, List, 


Interesting find. You reported that the silicon carbide meshes for drywall sanding are really just paper meshes coated with silicon carbide. 


I was trying to think of other materials that can handle high temperatures and ceramics came to mind. Ceramics are often used in metal casting processes. Aluminum Oxide, or even some sorts of fiberglass have high working temperatures. Ceramics generally have higher emissivity than metals (~ 0.7 I think). 


It looks like fiberglass meshes are often used to filter molten aluminum and iron for casting operations. Perhaps something like this would have longer lifetimes? Again, cost may become a big issue, but here are 2 that I found: 
http://www.ecplaza.net/trade-leads-seller/fiberglass-mesh-for-aluminium-filtration--6816138.html 
http://www.king-in-china.com/productview.asp?id=954 


Just throwing a few more ideas out there. 


-Matt Redmond 










-- 
Paul A. Olivier PhD 
27C Pham Hong Thai Street 
Dalat 
Vietnam 

Louisiana telephone: 1-337-447-4124 (rings Vietnam) 
Mobile: 090-694-1573 (in Vietnam) 
Skype address: Xpolivier 
http://www.esrla.com/ 

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