Open recirculating cooling system

Figure 1.3 Schematic of open recirculating cooling system.

This section is primarily concerned with the reviewing water treatment program selection process for open recirculating cooling systems and demonstrating the kind of information that may then be represented in a vendor s standard program selection guide. 

There are many open recirculating cooling systems that still do not have chemical dosing pumps available. This represents a serious risk, as the... 

Open Recirculating Cooling System and Control of Microbial Growth...422... 

Water in an open recirculating cooling system is characterized in comparison to make up water by the changes in some parameters due to several processes ... 

An original feature is the way the two open recirculating cooling systems are run (see... 

Heat exchangers are chiefly made of steel but may have units made of stainless steel, brass, carbon steel and bronze-copper alloys. Four open recirculating cooling systems are operated independently. 

An example of shallow-pit corrosion is given in Fig. 1-34. This corrosion damage was observed in an open recirculation cooling system after 18 months of operation. The tube, made of structural steel (St 37), showed several local attacks by pitting with a local corrosion rate of up to 3 mm year" . Iron sulfide was detected in the corrosion products. This indicates the presence of anaerobic sulfate-reducing bacteria (SRB). Under strictly anaerobic conditions the bacteria reduced the sulfates to sulfides leading to enhanced corrosivity of the medium (Weber and Knopf, 1994). 

Evaluate the scale potential of an open recirculating cooling system versus concentration ratio as an aid in establishing control limits. 

Lichen is in fact a symbiose between a weed and a fungus. They are not found in swimming pools. Mostly they are present in open recirculating cooling water systems. 

See also Chapter 9, Section 4, and the notes on Process Contamination in Section 10.8.28). Techniques for the on-line cleaning of open recirculating cooling water systems are often similar to those for preoperational cleaning in that generally there is a two-stage approach ... 

Almost all open recirculating cooling water systems operate within a pH range of 6.5 to 9.5. Occasionally this may be as low as 6.0 or as high as 10.0. Typically, however, water treatment programs are designed to function within only a narrow pH band of 0.5 to 1.0 pH unit or less. The specific... 

In open recirculating systems evaporation is the major factor in heat disposal. In these evaporative systems circulating water is continuously scrubbed with air, therefore saturated with dissolved oxygen. In contrast, water in closed recirculating cooling systems usually will contain minimum dissolved oxygen, even though the systems may include vented expansion tanks. 

As noted above, this chapter focuses on monitoring of corrosion and fouling in open recirculated cooling tower systems. Corrosion and fouling in other systems will be discussed briefly. Highly specialized systems, such as the extremely high-purity water systems for electronics or medical use, will not be considered. Potable water systems also will not be considered. The methods described are easily adapted for use in other industrial water systems. 

This presentation has focused on corrosion test methods in open recirculated cooling tower systems. This area is the most challenging, difficult, and important area of corrosion testing in industrial water. For economic and environmental reasons, water and inhibitor lost through blowdown must be minimized. Cooling tower systems are the systems that are most subject to operational upsets and operational variables. 

Open recirculated cooling water systems remove the heat picked up in plant by evaporative cooling. This may be done by a spray pond, for example, combining air conditioning needs with aesthetic considerations in industrial parks. The most common type of evaporative cooling, however, is effective in cooling towers of one type or another (Fig. 8.11). 

It has been weU-established that ozone is an efficient microbiological control agent in open recirculating cooling-water systems (cooling towers). It has also been reported that commonly encountered scales have not been observed in ozonated cooling systems under conditions where scale would otherwise be expected. The water chemistry of 13 ozonated... 

Uses Corrosion inhibitor tor open recirculating cooling water tems and process water treatment scale inhibitor tor heat exchangers and system surfaces contains dispersants to clean up fouled or scaled systems Features Rec. dissolved solids in system be maintained at 3-5 rycles of cone. 

H-900 provides broad spectrum control of slime-producing microorganisms such as bacteria, fungi, and algae in open recirculating cooling water systems. 

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