6 replies to this topic

[Lizette Process Engineer]

Our cooling tower water on the tar distillation plant currently exceeds the required amount of suspended solids and I am investigating the feasibility of installing a side stream sand filter.

Please assist with design methods and calculations to determine the correct sizing of such a sand filter and all factors that play a role in the decision making process i.e all input information required in the design process?

Thanks,

[ankur2061]

Hi,

You don't have to size the filter. The filter manufacturer will do it for you. You only need to provide the process data as a data sheet and the filter manufacurer will recommend the model / size of the filter. Some technical information for side stream filters can be found fom the links below:

http://www.prochemte..._Filtration.pdf

http://www.ethanolpr...cooling-systems

Hope this helps.

Regards,
Ankur.

[breizh]

Hi ,
Additional resource ( page 93)
http://spxcooling.co...undamentals.pdf



Hope this helps
Breizh

[fallah]

Hi,

As you know portion of circulating cooling water needs to be filtered (around 1-5%) to maintain the concentration of suspended solids below desired levels.
For specifying the side stream filter you need to make a material balance based on undissolved solid included in circulating water network. Obviously, the outlet stream by evaporation (named evaporation loss) isn't included undissolved solid and blowdown (as outlet stream) and make up (as inlet stream) are contained a lot of particulates. Hence, you can estimate the rate of particulates have to be discharged from the cooling water network.

Considering above, by knowing the amount of particulates in circulating water you can find the portion of it as the flowrate of water to be passed through filter and it, along with all other necessary information, could be reported to vendor for supplying the filter.

Fallah

[mm217]

Hi,

As you know portion of circulating cooling water needs to be filtered (around 1-5%) to maintain the concentration of suspended solids below desired levels.
For specifying the side stream filter you need to make a material balance based on undissolved solid included in circulating water network. Obviously, the outlet stream by evaporation (named evaporation loss) isn't included undissolved solid and blowdown (as outlet stream) and make up (as inlet stream) are contained a lot of particulates. Hence, you can estimate the rate of particulates have to be discharged from the cooling water network.

Considering above, by knowing the amount of particulates in circulating water you can find the portion of it as the flowrate of water to be passed through filter and it, along with all other necessary information, could be reported to vendor for supplying the filter.

Fallah

Dear Fallah'

It seems you have good knowledge about this case as the same as several other cases (i got it from your ouotes.)

I know the design rate of filtration in cooling systems and i know a little about backwash rate and required air flowrate too. I have a problem with necessity of relief device on sand filters. Most vendors pretend that sand filters are different from usual pressure vessels and do not really need PSV. In addition most of the time the design pressure of filters are the same as shut-off pressure of pumps so block-outlet case is not possible.Fire case is also the rare case for aquatic area. I heard something like auto-vent line or something like this. Do you know about the details of vent or relief lines of sand filter. I do appreciate for your help. may be i should try new topic....

[fallah]

mm217,

If the piping configuration around the sand filter causes you have air trap concern inside the filter, you can use an air vent valve at the top of the filter. It would relieve the trapped air and prevents air from collecting at the top of the filter.

Fallah

Edited by fallah, 23 April 2012 - 04:48 AM.

[mm217]

mm217,

If the piping configuration around the sand filter causes you have air trap concern inside the filter, you can use an air vent valve at the top of the filter. It would relieve the trapped air in the case of air accumulation at the top of the filter.

Fallah

Fallah

Thanks a lot, for your recommendation.
Then it is "air vent valve" used on top of these filters.

mm217