Online indirect air cooling high-back-pressure heat supply machine unit back pressure control system and method

Abstract

The invention relates to an indirect air cooling high-back-pressure heat supply machine unit back pressure control system and method. The system comprises a steam turbine low-pressure cylinder, a double-temperature-region steam condenser, an indirect cooling tower and a DCS control system, wherein a variable-frequency circulation water pump and a thermal resistor are arranged on a circulation water pipe entering the side B of the double-temperature-region steam condenser from the indirect cooling tower; the variable-frequency water pump is connected with a frequency converter; a pressure transducer is arranged at the side B of the double-temperature-region steam condenser; the frequency converter, the thermal resistor and the pressure transducer are connected with the DCS system through cables; a PID controller is used in the DCS control system for controlling the frequency converter; the back pressure practical value PV is measured through the pressure transducer; the PID controller outputs signals to the frequency converter used as an executing unit so as to regulate the frequency of the frequency converter; the power of the variable-frequency circulation water pump is further regulated; the flow rate of the circulation water is regulated; the goal of regulating the pressure of the double-temperature-region steam condenser is finally achieved. The system and the method provided by the invention have the advantages that the back pressure set value is optimized; the fuzzy self adaptation PID control is used for improving the dynamic regulating process; the ordinary PID control overshoot is reduced.

Description

technical field [0001] The invention belongs to the technical field of high back pressure heating, in particular to an online indirect air-cooled high back pressure heating unit back pressure control system and method. Background technique [0002] As a new type of heating method, high back pressure heating has gradually emerged in recent years. It has comprehensive benefits such as saving energy, improving the environment, and improving heating quality. It is an effective way to reduce unit energy consumption and is in line with national energy conservation and emission reduction policies . [0003] The indirect air-cooled unit uses circulating water to cool the exhaust steam of the low-pressure cylinder of the steam turbine, and the circulating water dissipates heat outward through the air-cooled island. For the unit, the heat lost in this part is a complete heat loss and cannot be effectively utilized. The purpose of the high back pressure heating transformation is to fu...

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Problems solved by technology

[0006] Solve the problem that the back pressure of the high back pressure heating unit cannot effectively realize the DCS online adjustment. At the same time, it overcomes the problem that the manual adjustment of the operator alone is prone to inaccurate adjustment at this stage, which affects the safety of the unit, and the insufficient optimization of the back pressure value leads to low heating efficiency. , propose an online indirect air-cooled high back pressure heating unit back pressure control system and method, realize the online back pressure control in the DCS system, and control the back pressure in the optimal range

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