Cooling tower side stream filter

Side stream filter, namely sand filter, continuously filter a portion of circulating water to remove debris and particles and return filtered to the cooling tower.

 

Side stream filter brings following benefits to a power plant:

 

1. Reduction in water consumption: Demand for makeup water in cooling towers is decreased with an increase in the system’s cycles of concentration. Essentially, higher cycles of concentration mean that water is being recirculated through the system longer before blowdown is required. Less blowdown reduces the amount of makeup water required in the system, resulting in water savings.

 

2. Reduction in energy consumption: Side stream filtration reduces the likelihood of scale and fouling on the heat exchangers. Even the smallest layer of scale or fouling on heat exchange surfaces can reduce the rate of heat exchange, forcing the system to work harder to achieve the desired cooling and in turn increases energy costs.

 

3. Reduction in chemical use: Chemicals are used to bind suspended particles in the water stream and prevent scaling and corrosion. Dirty water requires more chemicals than clean water because a buildup of solid contaminants provides a buffer that reduces the effects of treatment chemicals. A side stream filtration system can remove suspended particles, reducing the need for additional chemical treatments such as dispersants and biocides.

 

4. Lower maintenance cost: Traditionally, cooling towers are cleaned by draining the tower and having the sediment removed mechanically or manually from the sump. Costs associated with the cleaning process include downtime, labor, lost water, and additional chemicals. Cooling systems that are cleaned via side stream filtration routinely provide longer periods of continuous operation before being taken off-line for required maintenance.

 

5. Improvement in productivity and reduction in downtime: When a cooling system is fouled or has scale buildup, production may be slowed due to inefficient heat exchange equipment. In some cases, the cooling system and heat exchange equipment may need to be taken offline for repairs, decreasing production.

 

6. Control of biological growth: Biological growth control and reduction can mitigate potential health problems, such as those caused by Legionella. Legionella thrives where there are nutrients to aid its growth and surfaces on which to live. Use of side stream filtration can minimize habitat surfaces and nutrients by maintaining lower particle levels in the water system.