2 replies to this topic

[ashkan]

Hi

 

1.where is the location of side stream filter for cooling tower? is it at the discharge of cooling pumps or downstream of cooling water users?

there are some cases which side stream filter is located at the discharge of cooling pumps and filtered water is returned to basin. i think by this way we are wasting energy because of following reason:

if we assume that the required cooling water rate is 1000 m3/hr and we consider 5% of cooling water rate for filtering, then we should pump (1000+50=1050m3/hr) and if side stream filter is located at the return header , we would pump only 1000 m3/hr.

 

2.side stream filters are usually sand pressure filters and they need backwash to be cleaned.the rate of backwash are usually 6-8% of filtering flow. if we consider that the source of backwash water is from cooling water, we should pump (1000+ (50*1.08)=1054) m3/hr).is it right?

thanks

[fallah]

ashcan,

 

1- The side stream filter is in parallel to main cooling water line; then the total flow will be kept constant. The location of side stream filter is in pump discharge line before the condenser/heat exchanger to improve fouling avoidance inside the condenser/heat exchanger tubes...

 

2- Side stream filter back washing is to be done intermittently, once a day or on pressure drop as needed, then water loss due to back wash shouldn't be considered in continuous material balance of the cooling water loop...

[Mystified]

ashcan,

 

Few prefer dedicated connection and pump for side stream filtration.