filters technology for aluminum plant casthouse

[mech321]

Hi,
I work in an aluminum plant were we use melting furnaces for aluminum. We have some problems with our bag filters which seem to block all the time.
We use CAOH2 ( lime) which is injected in the fumes to neutralize the sulfur and chlorine oxides. The pipes which drive the lime to the filters are blocking all the time, especially when there is a wet environment.
The cleaning system for the bag filters is jet pulsing.
Personally I am not quite satisfied with this technology.
I was wondering if anyone has any different technology in mind, or any suggestions, which i would apprecciate to know.
Thanks

 

[smile1]

Check the line velocity in the injection pipes, or if they ever shut down. Typical is 4000 fpm, which precludes moisture problems from the process. Check your air supply to the injection system. If it's a blower, ensure that it is still hot, if compressed air, check the traps. Good luck.

 

[Lakeshore]

I agree... check your flows to the bag filters. I've seen problems like this before and most were attributed to low flows. If you are going to measure flow, RESEARCH the probe types out there... single-points are useless due to non-laminar flows, flow restriction devices (i.e. orifice plate) make NO sense what-so-ever (why induce non-recoverable pressure drop?). Check out

http://www.airmonitor.com,

they even offer mass density compensation! Yes, temperature DOES affect air flow rates! Assuming your process temp. fluctuates. Best regards,

Lakeshore

 

[radicare]

Mech321,
Iam having this kind of problem before in our incinerator(Malaysia),these are several suggestion could help you to reduce eliminate your problems.

1. What type of filter bags that are you using.
2. What your inlet bag house (dust collector) flowrate.
3. how many filter bags that you use in your bag house.
4. What your filtering velocity design?.
5. How many kg/hr of lime that you injected
6. Are your system using fan blower or compressor air
if blower can you give the speed rating.
if compressor how many pressure that you using at system.
7. how about your lime pipeline diameter
One thing that you need to remember,Lime Ca(OH)2 are consider as Hydrated lime.CaO mix with water to perform Hydrated lime.Inthis case if lime exposed with certain rate of moisture they will become harder.Please give me your data(refering to item 1 to 7) and i will give your some better solution.