Re: Bag House Design Problem
Qustions:
What is the partical size in microns?
How much air will you capture in m^3/hr?
What are the densities (not bulk) of the materials?
If you have a small system a cartridge type collector will allow you to keep a set of filters for each product. I don't think you can get bags or filters very clean without removing and blowing off. ■
Re: Bag House Design Problem
Dear Serdman,
Thanks for your suggestion.
Please note the size of the particle to be captured is 3 Microns. Specific gravity of the dust is not exactly known right now but can be considered to be 1.2
Application Data:
Air Volume : 5400 CMH
Application : Free Flowing Dust collection [Product recovery]
Dust Loading : 20 mg/m
Nature Of Dust : Hygroscopic & very fine
% Moisture : Nil
Working Temp : 65 Deg C
We welcome your suggestion for using separate set of bags for recovery of different products from the single bag house.
We had also considered this option and selected pleated type filter bags but as we were not much sure that this will prevent the contamination.
Ofcourse the degree of the cleanliness of the Bag house before each change over is in customer's scope, but the construction of the bag house is to be such that it helps the user in terms of easy and satisfactory cleaning and quick change over.
We would like to request you to please extend your further help and let us know your experience if you have already used this option.
Thanks & regards,
Vikesh Patel ■
Re: Bag House Design Problem
A spare set of cartridge filters is the right way. The flow rate is low and the size of the filter will be small.
You will need to clean the baghouse internals between batches. The turn-around time should be small.
Michael Reid. ■
Re: Bag House Design Problem
Dear Vikesh,
Based on the given data, the following calculation:
In case of a jet cleaned bag dust collector as you describe:
3 micron, particle density 1200 kg/m3, results in a suspension (or floating) velocity of 0.27 m/sec.
The vertical air velocity between the filter elements must be lower than the suspension velocity, assume in this case approx. can velocity= 0.18 m/sec
The air flow is 5400 m3/hr = 1.5 m3/sec
Filter receiver area = 1.5 / 0.18 = 8.3 m2 (approx. 3x3 m)
With a filter load of 1 m/min, the filter area is 90 m3/sec / 1 = 90 m2
Replacing this rather big bag house for a cartridge collector as suggested by Michael, reduces the size (based on a certain amount of captured dust) of the installation and the dust recovery is then by scraping the cartridges after changing.
As always, the finest particles cause the biggest problems.
Have a nice day
Teus ■
Teus
Re: Bag House Design Problem
Originally Posted by Michael Reid
You will need to clean the baghouse internals between batches. The turn-around time should be small.
Michael Reid.
Thanks Mr. Michael Reid,
But do you have any past experience in which you have prevented product contemination in such situation.
If you have done it earlier, we would be happy and thankful to know about it.
Regards,
Vikesh Patel ■
Re: Bag House Design Problem
Hi Vikesh,
I have seen this technique used where cross-contamination is to be avoided. You have to ask:
Is the value of the product such that the extra labour for change-over and cleaning between batches is justified?
What are the batch sizes? i.e., what is the frequency of change-over?
Cartridge filters will retain a fair amount of product in the pleats but that will be recovered when the next batch is made. Seal the filters in plastic bags when not in use.
You will need to provide additional access points (manholes) in the baghouse casing for proper cleaning.
Michael Reid. ■
Re: Bag House Design Problem
Originally Posted by Michael ReidI have seen this technique used where cross-contamination is to be avoided. You have to ask:
Is the value of the product such that the extra labour for change-over and cleaning between batches is justified?
What are the batch sizes? i.e., what is the frequency of change-over?
Cartridge filters will retain a fair amount of product in the pleats but that will be recovered when the next batch is made. Seal the filters in plastic bags when not in use.
You will need to provide additional access points (manholes) in the baghouse casing for proper cleaning.
Michael Reid.
Thanks Mr. Michael Reid,
The extra cost of bag house cleaning is ofcourse justified as it decereases the capital investment .
The batch size needs minimum of 2 to 3 days of process time and it is allowed to have 4 to 6 hrs of process shut down before change over. I think it would be sufficient time to prepare bag house for next product.
We do not have any problem with the extra amount of the product retaining in the bags while not in use, as it will be reimbursed in the next batch.
Thanks for techniqes suggested for preserving the used bags for the next batch and for proper cleaning of bag house.
Thanking you once again for your co-operation,
Regards,
Vikesh Patel
Cell.: ++91-98250 40848 ■
Re: Bag House Design Problem
G'day,
I am working on a project in the agri-chemical industry and there is nothing particularly special in the design of their systems. To eliminate cross-contamination, it is literally a case of taking things apart completely and carrying out a thorough wash down and clean out. For things like filter bags, you can have separate sets of bags for each product, but then you need to have secure storage areas for each bag set.
On the machinery side, everything needs to be able to be taken apart and then reassembled easily, or accessed by cleaning equipment. Also, you need to be aware of confined space dangers where inerting gasses are in use and personnel have to go into those areas.
To outsiders, it might seem an overkill, however the only other option is to have duplicate processing lines which is extremely expensive. ■
Bag House Design Problem
Dear friends,
I am here to have your kind suggestions to do recovery of two different products which are in the dust form, by using single bag dust collector avoiding the product contamination.
Please note, my problem is to do recovery of the dust of the finished products which are costlier as well as nuisance to the surroundings.
Size of the dust particle is very fine, and the dust load is 20 mg/m3. Air temperature is 65 Degree C.
Now my actual problem is to avoid contamination of different products being produced from the same production line in different batches at different times.
So can anybody help me to design common bag house which can be completely cleaned before product change over. Please note we have to optimize the cleaning time too.
If you have any other alternatives to my problem please let me know.
Please feel free if you need further information.
Thanking you in advance,
Vikesh Patel ■