Q: What is the steam drum of a steam generator?

A:

1. Steam drum of steam generator

The steam drum is the most important equipment in the steam generator equipment. It is the link between the three processes of heating, vaporization and superheating of the steam generator, and plays a connecting role.

The drum water level of the steam drum boiler is an extremely important indicator during the operation of the boiler. Only when the water level is maintained within the normal range can good circulation and evaporation of the boiler be ensured. If the water level is too low during operation, it will cause the boiler to be short of water. Serious boiler water shortage will cause the water wall tube wall to overheat, and even cause equipment damage.

If the water level is too high during boiler operation, the steam drum will be filled with water, which will cause the main steam temperature to drop rapidly. In severe cases, water will be brought into the turbine with the steam, causing serious impact and damage to the turbine blades.

Therefore, the normal drum water level must be ensured during boiler operation. In order to ensure the normal drum water level, boiler equipment is usually equipped with high and low drum water level protection and water level adjustment control systems. The drum water level is usually divided into high first value, high second value and high third value. Low drum water level is also divided into low first value, low second value and low third value.

2. During normal operation of the boiler, what is the requirement for the drum water level?

The zero point of the drum water level of a high-pressure drum boiler is generally set at 50 mm below the geometric center line of the drum. The determination of the normal water level of the steam drum, that is, the zero water level, is determined by two factors. In order to improve the steam quality, the steam space of the steam drum should be increased as much as possible to keep the normal water level low.

However, in order to ensure the safety of water circulation and prevent evacuation and steam entrainment at the entrance of the downpipe, the normal water level should be kept as high as possible. Generally, the normal water level is set between 50 and 200 mm below the drum center line. In addition, the appropriate upper and lower water levels for each boiler must be determined based on the water velocity measurement test of the water-cooled wall downpipe and the supervision and measurement test results of the water vapor quality. Among them, the upper limit water level is determined by whether the quality of water vapor deteriorates; the lower limit water level should be determined by whether the phenomenon of evacuation and steam entrainment occurs at the entrance of the downpipe.