Carryover in boilers refers to the phenomenon whereby small droplets of water are carried along with steam which enters the steam turbine or other downstream equipments. It is a common occurrence in boilers and power plants that use steam as a primary source of energy. In a steam generating plant, carryover can cause various problems resulting in equipment damage, reduced efficiency, and increased operational costs. The following is a detailed explanation of carryover in boilers:
Causes of Carryover in Boilers:
Poor water quality: One of the leading causes of carryover in boilers is poor water quality. Water that is too impure or contains high levels of dissolved solids or contaminants can cause foaming and priming, which leads to carryover.
High steam velocities: High velocity of steam inside the boiler can cause water droplets to break away from the surface of the water and be carried along with the steam, leading to carryover.
High boiler pressure: High boiler pressure also contributes to carryover as it results in more steam production and creates more force, which can cause water droplets to be carried along.
Defective steam separation equipment: Defective steam separation equipment, such as separators or steam drums, can also contribute to carryover in boilers.
Effects of Carryover in Boilers:
Damage to steam turbines: Since carryover can cause water droplets to be carried along with steam, it can cause erosion and corrosion of the blades and casing of steam turbines, which can lead to a severe decrease in efficiency and result in equipment damage.
Reduced boiler efficiency: Carryover can cause a reduction in boiler efficiency as it results in the loss of water and steam from the system.
Safety concerns: Carryover can also lead to safety concerns as it increases the risk of water hammer, a phenomenon that occurs when water droplets collide with steam with high force, leading to severe damage of equipment and possibly injuries to personnel.
Methods of Controlling Carryover in Boilers:
Proper water treatment: Water treatment is the most effective way of controlling carryover in boilers.
1.Proper treatment of the feedwater prior to being fed into the boiler can prevent the formation of scale and other impurities, reducing the risk of foaming and priming.
2.Steam separation equipment: Installing efficient steam separation equipment such as baffles, separators, and steam drums can reduce the amount of water that is carried over with steam.
