Ozonated cooling systems

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... 

Identifying acceptable operating range for ozonated cooling systems. It... 

Puckorius, P.R. 1995 Legionnaires Disease Outbreaks in USA Cooling Systems paper presented at 1st Australian Conference of the International Ozone Association February 1996... 

Iodine, ozone, and peracetic acid are used in cooling systems, but have tended only to attract limited advocates. These oxidizers are discussed in the following sections. 

Another product is based on the combination of dosing an iodophor to the cooling system and periodically generating ozone for subsequent addition to the cooling water to regenerate the iodine. 

Thus, the practical, cost-effective benefits for the use of ozone in cooling systems often remain elusive except for certain clearly defined projects. 

Large industrial cooling systems and those with high organic loading or process contamination require high ozone dose rates and several application points. This approach is unlikely to be cost-effective. 

For large cooling systems, it is usually necessary to have multiple injection points. For systems with less than 7 to 8 times volumes of cooling water turnover per hour, the application rate of ozone will need to be increased. 

Some ozone suppliers recommend that the bypass loop be taken from and returned to the pressure side of the main recirculating pumps. A contact/degassing vessel is recommended to prevent air bubbles from entering the cooling system pipework. All sidestream pipework containing ozonated water should be of uPVC or stainless steel construction. 

It is quite probable that as the reuse of water for cooling system makeup becomes more common, ozone will establish a bigger role than at present, by pretreating some supplies, perhaps for the removal of difficult hydrocarbons and other contaminants. For such applications, it will then compete with carbon filters and similar technologies, and ways will have to be found of making it more cost-competitive. 

The standard disinfectant for many of the world s potable drinking water supply systems (ozone and others are also widely used) and the product of choice for large cooling systems, usually available as a gas for lowest cost, but can be provided by liquids such as sodium hypochlorite (bleach) or solids such as calcium hypochlorite or isocyanurates. Any process contaminant leak tends to increase the chlorine demand, requiring additional chlorine to maintain disinfection rate. Poor penetrant of biomass and significantly reduced efficiencies over pH 8.0. 

To dry the air for generating ozone, a system of dehydration by cooling was chosen, as pure air compressed to 71 p.s.i. was available. It sufficed, at this pressure, to reduce the temperature of the compressed air to —35° C. in order to reduce the humidity to... 

For multilamp photo reactors to handle large capacity, about 200-500 lamps can be replaced by one 30 kW medium-pressure high-intensity lamp at the same operating cost, but with much lower volume. However, systems with medium-pressure lamps require an efficient cooling system to maintain the desired reactor temperature. For UV/ozone AOP, ozone dissolution is enhanced by efficient design of the diffusers to improve the mass transfer. 

Ethylene-Propylene-Diene-Monomer (EPDM) Rubber. The main properties of EPDM are its outstanding heat, ozone and weather resistance, as well as its electrical insulating properties. EPDM rubber finds use in vehicles (weather seals in windows and trunks, cooling system hoses), in safety equipment (seals in respirators), roofing (waterproofing of roofs), and playground surfacing. 

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