3. The need to recover condensate and flash steam

Recovering condensate and flash steam has multiple benefits.

First, since it, holds about 20% of the energy in steam, returning condensate reduces the plant’s fuel consumption and consequently the steam fuel bill. Returning condensate back to the boiler feed water tank, increases the boiler feed water temperature, and every 6ºC heat gain in boiler feed water temperature, results in a 1% fuel savings.

The second obvious benefit is that it reduces the fresh makeup water requirement of the boiler resulting in water savings. This is particularly important for plants that are committed to reducing their water footprint as part of their sustainability goals or plants located in areas where water availability is an issue and water costs are high.

Condensate does not contain the impurities typically found in water. This is because it is formed when steam condenses. This absence of impurities eliminates the need for water treatment, resulting in cost savings. This advantage constitutes the third benefit of condensate recovery.

The fourth benefit also arises from condensate’s purity which helps reduce the overall Total Dissolved Solids (TDS) in boiler feed water. Consequently there is a decreased requirement of blowdown, leading to lower blowdown losses and lower boiler fuel consumption.

The fifth benefit of recovering condensate and flash steam is because it increases the temperature of boiler feed water. This rise in temperature drives out dissolved oxygen which is highly corrosive. Eliminating dissolved oxygen contributes to the extended life span of the steam system. Additionally, reducing or eliminating the need for oxygen scavengers, not only reduces treatment costs, but also lowers feed water TDS, thereby reducing blowdown losses.

Elevating the temperature of the boiler feed water offers an additional advantage: it reduces thermal stresses exerted on the boiler’s metal surfaces. This reduction in thermal stress represents the sixth benefit of recovery, achieved by minimising the temperature difference between incoming water and the operating temperature of the water inside the boiler.

Improving boiler feed water temperature also improves the boiler throughput. This is yet another benefit of recovering condensate and flash steam.