<font color='black' size='2' face='arial'><span class="Apple-tab-span" style="white-space:pre"> </span>Not worth messing with in my opinion. 1. Any fixed surface will still coat, even at very low tar content. 2. At high temperature, C+CO, C+H2 reactions will eat up graphite, 3. if resin coated, will not handle temperature and solvents in the gas. <br>
<br>
<div style="clear:both"><font class="Apple-style-span" face="arial">Sincerely,</font><br>
<div><font class="Apple-style-span" face="'Comic Sans MS', sans-serif">Leland T. "Tom" Taylor</font></div>
<div><font class="Apple-style-span" face="Arial, Helvetica, sans-serif">Thermogenics Inc. </font></div>
</div>
<br>
<br>
<div style="font-family:helvetica,arial;font-size:10pt;color:black">-----Original Message-----<br>
From: Viswanathan KS <viswanathanks@gmail.com><br>
To: Discussion of biomass pyrolysis and gasification <gasification@lists.bioenergylists.org><br>
Sent: Sun, Jul 15, 2012 10:12 pm<br>
Subject: Re: [Gasification] Graphite Heat Exchangers for Producer Gas?<br>
<br>
<div id="AOLMsgPart_2_9f01319b-c231-4a80-8d6c-fa198083b386">
<div>Process for producing graphite tubes:</div>
<div><br>
</div>
<div>Quote</div>
<div>Synthetic graphite is manufactured from crude oil cokes and pitch. The pasty mixture is shaped into </div>
<div>monolithic blocks or tubes. Tubes are extruded whereas blocks are usually vibration molded. The </div>
<div>shape is then carbonized at 900ºC (1650 F)for a few hours and then fully graphitised at 2900ºC (5250 </div>
<div>F) for several days. The block or tubes are then impregnated with synthetic resin that is then </div>
<div>
polymerized to render them totally impervious to gases and fluids. </div>
<div>The resulting material is fully corrosion resistant to most common acids (sulfuric acid, hydrochloric </div>
<div>acid and of course industrial phosphoric acid) and has a very high thermal conductivity of around 80 </div>
<div>W/m.K for tubes or 140 W/m.K for blocks when totally graphitised. The tube wall is quite thick, 6 </div>
<div>mm (1/4”) and the individual tubes are 3 meters (10’) long.</div>
Unquote
<div><br>
</div>
<div>ksv<br>
<div class="gmail_quote">
On Mon, Jul 16, 2012 at 9:27 AM, Bob Stuart <span dir="ltr"><<a href="mailto:bobstuart@sasktel.net">bobstuart@sasktel.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">
In the early days of graphite fiber/graphite matrix brake disks on race cars, the ceramic coating would sometimes crack, allowing oxygen onto the hot graphite. The result became known in the pits as "Designer Coal."<span class="HOEnZb"><font color="#888888">
<div>
<br>
</div>
<div>Bob</div>
</font></span>
<div>
<div class="h5">
<div><br>
</div>
<div>
<div>
<div>On 15-Jul-12, at 9:50 PM, Viswanathan KS wrote:</div>
<br>
<blockquote type="cite">IMO the graphite tubes are not coated.<br>
<br>
<div class="gmail_quote">
On Mon, Jul 16, 2012 at 8:45 AM, Bob Stuart <span dir="ltr"><<a href="mailto:bobstuart@sasktel.net">bobstuart@sasktel.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Would the coating that protects the graphite from oxidation not also work on copper?<span><font color="#888888"><br>
<br>
Bob</font></span>
<div><br>
<br>
On 15-Jul-12, at 8:10 PM, Tom Miles wrote:<br>
<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div> Graphite heat exchangers are now used on domestic condensing hot water boilers. (See SGL Group.) Heat transfer is reportedly 8 times that of stainless steel. Why not use them for cooling and condensing producer gas?<br>
<br>
<br>
<br>
Tom<br>
<br>
</div>
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<pre style="font-size: 9pt;"><tt>_______________________________________________
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