Re: Reek Pipe Blockages
The sock filter will plug eventually and then you will have a mess.
put simply -what goes in must come out- how close is the static level of material to the bin vent pipe?
Can you move your vent to the top of the storage bin side wall? this would solve alot of your trouble if it is out of the products range-A simple 4 inch elbow with a 20-30 mesh screen will work nicely. ■
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Izaharis,
The vent pipe is very close to the working level in the hopper. The hopper is 3m hign and 2m square. The working level is probabaly 1.5m from the top and the vent is attached to the top at an angle of 30 to the horizontal. I will try and get a picture.
I guess the vent should be vertical but the whole system sits beneath ash hoppers and hence the vent, which is 50m long need to escape the hopper at a low angle. ■
Vent Line Blockage
Dick,
Vent lines that contain dust should be designed as pneumatic conveying lines to convey dust particles to a dust collector. Conveying velocity in the vent line should be 30 to 40 ft/sec. The geometry of the conveying line should be the same as that used for pneumatic conveying. If you can make these changes, your vent line blockage problem will go away.
Since you already have a vent line and a source of vacuum, you are getting blocking because of low conveying velocity. You can introduce additional air into the line to increase the velocity. This can be done close to the suction point with a butterfly valve. But make sure that the present source of vacuum can handle this additional air, and if needed you may increase its speed.
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Email
olypcc@aol.com
Ph and Fax: 304 346 5125 ■
Vent Line
Dick, Amrit is right if you convert that line and turn it into a high velocity vacuum AKA (screaming super sucker) it will work well- please send me a large picture at your convenience so I can take a look just to be sure.
leon z ■
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Thanks Armit and Izaharis,
I agree with your diagnosis. I do need to promote a greater flow through the reek pipe. The suction pressure is quite low, typically -30mbar but it does drop significantly when the plant is at part load.
To help I have attached a photo and sketch.
Much respect.
Dick
Attachments
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Re: Reek Pipe Blockages
Reek Pipe Wreaking Havoc-Sorry Dick I Could Not Resist :0)
Hello Gravity is obviously your worst enemy is there room to install a large rotary lobe or screw blower-not air compressor near the knife gate valve and splice in a Y with a flap gate check valve-I am sure that would work and would be energy efficient as well.
leon Z ■
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It sounds like your suggesting an eductor in the reek pipe to induce a flow. That sounds interesting.
However, I dont want to introduce too much air into the system so I might use fluegas at 120 degC with a fan rather than a blower. I guess I will need to do the calcs to see what flow would be needed to fluidise eveything. The problem is I dont know much dust travels up the reek pipe under normal conditions and more importantly blockage conditions.
I could try what you suggest with a temporary compressed air supply. I wish I could see what was going on inside the reek pipe. Perhaps mount a camera in the Y piece?
Thanks.
Dick ■
Reek Pipe
Hello dick,
A camera would definetely show you what is going on. their are several very good small cameras on the market-probably with your application it would be simpler to just buy the least expensive surveilance camera set up from radio shack as an example or any miniature camera used in radio control aircraft which are very small in size and less expensive-simpler beacuse they are smaller in size to fit in a Y with a reducer bushing and a small piece of plexiglass covering the hole to protect the lens. ■
Reek pipe blockages
I have a hopper vent pipe which discharges surplus air from six air slides enter a hopper with PFA. The pipe is vented to a low pressure source but keeps blocking, partly due to the vent pipe geometry. I can change the pipe geometry but was wondering whether sock filter in the vent pipe might do the trick? ■