Thermodynamic system of steam turbine and method of improving efficiency thereof

Abstract

The invention discloses a thermodynamic system of a steam turbine and a method of improving efficiency thereof. The system comprises a primary high pressure cylinder, a primary intermediate pressure cylinder and primary first low pressure cylinder. Main steam is directly input into the primary high pressure cylinder, then is input into the primary intermediate pressure cylinder and then is input into the primary first low pressure cylinder through a primary water-steam separator and a primary reheater to become dead steam input to a condenser. At a subcritical parameter, the heat consumption of the system can be reduced to 7256 kJ / kWh, the thermal efficiency of the steam turbine can be improved to over 49%, and the exhausting mass proportion of the low pressure cylinder is reduced to 48.5%of total admission mass. The thermodynamic system reaches a conventional energy consumption level which exceeds that of a supercritical steam turbine.

Description

technical field [0001] The invention relates to a steam turbine thermal system capable of improving efficiency. The invention also relates to a method of increasing the efficiency of said system. Background technique [0002] At present, the steam turbines used for steam turbine power generation in the domestic power industry generally adopt the back pressure type or condensing type design. For a subcritical condensing steam turbine, its thermal system consists of a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder. The wet steam discharged from the low-pressure cylinder enters the condenser, and the internal energy in the exhaust steam is taken away by the circulating water. Its heat consumption rate is generally not lower than 7900kJ / kWh. The heat rate of the back pressure steam turbine is generally not lower than 8000kJ / kWh. Generally, the power industry adopts the method of increasing the initial steam parameters and reducing the final st...

AI Technical Summary

Problems solved by technology

However, the current subcritical unit adopts the layout structure of high-pressure cylinder + medium-pressure cylinder + low-pressure cylinder. The exhaust steam flow of the low-pressure cylinder reaches more than 57% of the main steam flow. The humidity of the exhaust steam of the low-pressure cylinder is relatively high, that is, its internal energy is still high. , generally close to 2300kJ / kg, while the internal energy of condensed water is only 150kJ / kg, which requires a large amount of cooling water to cool, and strip this part of the internal energy difference from the system without doing any work at all

Images