The back pressure unit is a unit operating by combined production of heat and electricity (cogeneration). Cogeneration enables rational use of energy and is an important measure to save energy. Among many turbine-generator units, the back-pressure machine has the highest thermodynamic cycle efficiency because it eliminates the loss of condenser cold source, thereby reducing coal consumption for power generation and saving energy. energy, so it is widely used.
However, the back pressure machine also has the following disadvantages: it has poor adaptability to load changes, and the power output of the unit is subject to thermal load changes. When the heat load is low, the efficiency of the steam turbine decreases, thereby reducing the economic benefits.
Let’s take as an example a heatingrepresentative die of 35 t/h with three steam parameters: 3.9 MPa/450 ℃, 5.2 MPa/485 ℃ and 6.4 MPa/500 ℃. The steam parameter of a thermal power plant equipped with a 35 t/h boiler is believed to be 5.2 MPa/485 ℃. This can be explained by the following four points: ① In terms of power generation efficiency, the boiler pressure of 35 t/h. the boiler goes from 3.9 MPa to 5.2 MPa