Date: Wed, 20 Jan 2010 09:18:20 -0500
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Joseph Passante <Joe**At_Symbol_Here**EHRS.UPENN.EDU>
Subject: Re: Flammable gas in a quartz tube/electric furnace assembly

What the original poster describes is very common.  Nanotube are made this way (lab scale)  and furnaces used to pacify surfaces (such as silicon wafers) in fabrication labs.  The only difference is the flow volumes.  Is it CFM or scfm?  I've never seen flow rates in excess of a 100 cc/min.

Hello everyone:


A researcher here plans to continuously flow 100 % flammable gas (methane, ethylene, hydrogen, or mixture) at 1 cfm through a quartz tube/electric furnace assembly that is heated to 800 degrees C (exceeds the auto-ignition temperature of the gases). The researcher intends to have four (4) of these units (~18=94h x 24=94d x 60=94 w) in the lab;  at least two units will be active throughout the day.


The discussion centers on where to safely set up and operate them. The researcher proposed mounting the units on open benchtops (two per benchtop) to accommodate their size and facilitate use (the gases would be piped to the units via stainless steel tubing from an adjacent gas room). Though seemingly practical, I feel this would require considerable $$ investment in engineering controls (canopy hood, blast shields, etc.) to adequately protect the research staff from potential mishaps (gas leaks, explosions). My thought is to mount the assembly in the lab=92s wet process hood (vertical laminar flow) and lower the sash during operation. Though not ideal, it would reduce the potential of these mishaps. NOTE: There are only two available process hoods in the lab, hence, only two assemblies would be up and running (not a bad thing in my opinion).


Joseph R. Passante, CIH, CHO
Associate Director
Chemical Hygiene Officer
Environmental Health & Radiation Safety
University of Pennsylvania

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