Putting Cooler Condensers Back to Work

Cooling condensers are among the most critical equipment in plants with steam-turbine-driven equipment, where the turbine steam exhaust is condensed by means of cooling water. (Typical industries include steel, pulp and paper, power and food processing.) The main purpose of these heat exchangers is to maintain vacuum on the turbine exhaust and to recycle steam as high purity condensate. The steam condenses within closed-loop systems, creating a partial vacuum near absolute zero pressure. The resulting high purity condensate is pumped back into the cycle for return to the boiler.Get more news about Condenser Expansion Machine,you can vist our website!

The condensers are designed to prevent direct mixing between the shell-side steam and the cooling water flowing through the tubes. Isolating the steam from the cooling water maintains the high purity water, allowing the condensate to be returned to the boiler. This minimizes the water purification costs for the feedwater. Figure 1 shows a simple example of the basic process flow for typical condensers.
Water Impurities and Biofouling
When cooling condenser performance is compromised by corrosion, biofouling and other problems, system performance suffers. Because the condenser plays a key role in performance, hidden problems can unexpectedly result in de-ratings.

Some operations draw cooling water from nearby rivers. Screening processes at the intake, however, may be insufficient to remove all sediment and other impurities. Untreated cooling water has the potential to support biological growth and leave deposits that can collect inside and around the cooling condenser tubes and tubesheet.

Unit reliability is affected if the cooling water leaks into the condensate system and carries with it dissolved minerals and biological impurities. If the boiler water impurities cannot be managed by water treatment and boiler blowdown, system impurities may result in boiler and turbine damage.
Tube inside-diameter (ID) growth due to mineral deposits or fouling reduces the surface area available for heat transfer. When the surface area lost to plugged tubes or reduced heat transfer exceeds this threshold, a significant decrease in the unit’s overall efficiency and capacity rating is common.

Thus, plant operators continuously monitor condensate/feedwater purity. This allows them to detect significant condenser-tube leaks and other problems within minutes of occurrence — and provides the opportunity to plan solutions. The response to indications of these leaks can be delayed, however. Usually, it is a function of following established limits, evaluating steam-load requirements and any impacts on operating costs.

Loss of vacuum affects the efficiency of the entire thermal process. In addition, impurities in the condensate can damage the boiler and turbine components, resulting in reliability and capacity issues.