The steam desuperheating system is a kind of equipment commonly used in modern energy-saving projects. The equipment is composed of two parts: a desuperheating water atomization device and a combined vaporization unit. The desuperheating water is pressure-atomized and dispersed through the desuperheating water pump atomizing nozzle. In the high-temperature steam flow, the combined vaporization unit further compulsively rotates, shears and breaks the atomized desuperheating water, and is vaporized on the surface of the internal parts of the vaporization unit, which significantly strengthens the vaporization process and achieves the desuperheating of high temperature steam .
The basic way of desuperheating water pump steam desuperheating
The desuperheating process refers to reducing the temperature of the superheated steam to a saturated state, or reducing the superheat of the steam. Most desuperheaters are designed to keep the steam temperature close to the saturation temperature (typical minimum is 3°C above the saturation temperature). If you want the discharge temperature of the desuperheater to exceed the saturation temperature by more than 3°C, it is also possible, and it is often used. There are two basic forms of desuperheater for steam desuperheating by desuperheating water pump:
1. Non-contact type-the medium of cooling steam is not directly connected with the cooled steam. Liquid and gas with lower temperature can be used as cooling medium, such as air. This type of desuperheater is a shell and tube heat exchanger. The superheated steam enters one side of the heat exchanger, and the cooling medium enters the other side of the heat exchanger. When the superheated steam passes through the heat exchanger, heat is transferred from the superheated steam to the cooling medium.
The outlet temperature of the superheated steam is controlled by adjusting the inlet flow rate of the superheated steam or the flow rate of the cooling medium. However, the operability of adjusting the inlet flow rate of superheated steam is usually poor, so most systems adjust the flow rate of the cooling medium.
2. Direct contact type—The medium used to cool the superheated steam directly contacts the superheated steam. Usually the cooling medium and the superheated gas are the same substance, but in a liquid state. Water is usually used for steam desuperheaters. A typical direct contact desuperheating device is shown in Tong 15.1.3.
When the desuperheater is working, a certain amount of water is added to the superheated steam through the desuperheating water pump of the mixing device of the desuperheater. When the water enters the desuperheater, it absorbs the heat of the superheated steam and evaporates, so that the temperature of the superheated steam follows. reduce. The flow control of the added water is accomplished by measuring the steam temperature downstream of the desuperheater. The temperature of the desuperheated steam is usually set to be 3°C higher than the saturation temperature. In this arrangement, the steam inlet pressure of the desuperheater should be kept constant.
