Simulation Research On Reheat Steam Temperature Control Strategy Of 660MW Double Reheat Unit

Nowadays, mankind is confronted with a severe energy problems.As a large energy consumption, energy-saving is of great significance for power plants. Compared with the traditional single reheat unit, using secondary reheat can further improve the thermal efficiency of the unit and meet low-pressure cylinder unit eventually exhaust humidity requirements. Developping the double reheat ultra-supercritical boiler which is more efficient and environmentally friendly with independent property rights is an important development direction of China’s power industry. However, the real application of double reheat units are faced with many difficulties: Adding a UHP cylinder, the main steam valve, regulating valve and bypass system, result in the unit cost increasing and shafting become more complex; adding a First Reheater makes the boiler structure and heat absorption ratio changed, increasing the difficulty of design and operational difficulty. It is need more accuratelogic to control boiler opeation,especially reheat steam control.Therefore, it is crucial to find an effective adjust strategy.Double reheat boiler soda parameter has the following main features: Compared to single reheat boiler units reduce heat output, the unit thermal efficiency is increased; the proportion of main steam heat is reduced, but the heat of high-pressure and low-pressure reheateris increased, that is double reheat boiler can not copy a conventional reheat boiler design.Reheat steam temperature regulation designmust take into the heat from main steam system to reheat steam.According toreheat steam temperature’s characteristic of the double reheat unit, the paper introduces the present development situation of ultra supercritical double reheat unit, research results and the necessity ofapplication of large-capacity ultra-supercritical double reheat unit. It describes the main use of simulation algorithm module, for the problem of double reheat steam temperature control system. It propose a reheat steam temperature control strategy, the reheat temperature reaches the rated value by adjusting the flue gas re-circulation fan. At the same time, through flue gas damper to adjust the reheat steam temperature of high-pressure and the low-pressure side.Through simulation machine verification shows that this control strategy can achieve effective control of the two reheat steam temperature, and then heat the secondary motor group to promote the use of great significance in our country which can achieve effective control of the two reheat steam temperature.It is great significance to promote the use of double reheat unit in our country.