Are you aware of the precautions to take when using a desuperheater during boiler startup? Join us as we explore these important considerations!

Boiler economizers are generally used in steam supply pipelines. When the steam temperature required by the user is lower than the boiler outlet temperature, an economizer is used to lower the steam temperature and meet the user's requirements. This device, which uses water as a cooling medium to regulate the superheated and reheated steam temperatures, serves to control and maintain the superheated or reheated steam temperature at the specified value, and to prevent the overheating and reheating tubes from being overheated.

Warning: Tips for Using the Temperature Reducing Valve

During the pressure slide start-up process of the unit, prior to the turbine surge, the boiler side generally does not use water spray for temperature reduction to regulate the steam temperature. However, when it is necessary to introduce reduction water later in the process, it should be used rationally based on the characteristics of the reduction cooler's layout and the parameters under different conditions, ensuring both the safety of the superheater and a stable rise in the main steam temperature.

2. In cases where the boiler's thermal load is low, although the steam flow rate is smaller, the steam turbine requires a lower steam temperature accordingly, which generally does not lead to excessively high wall temperatures in the screen-type superheater. At this point, if a primary desuperheater is used to control the steam temperature, the long steam flow path and low flow velocity after the desuperheating water injection result in a very slow response of the boiler outlet steam temperature, prone to low steam temperatures, and possibly causing waterlogging in some serpentine tubes. Therefore, it is advisable to use a secondary desuperheater located near the steam outlet for微量water injection and fine-tuning of the steam temperature.

As the boiler thermal load gradually increases (above 30% of the rated load), the increase in steam flow through the header superheater is insufficient to cool its tube walls, often leading to higher tube wall temperatures, even exceeding the allowable limits. At this point, the steam temperature regulation should primarily utilize a single-stage desuperheater, which can both lower the header superheater's inlet temperature and increase the flow through it and subsequent heating surfaces, thereby enhancing the safety factor of the header superheater.

The above introduction covers the precautions to be taken when using a desuperheater during boiler startup. We hope it is helpful to you!