| This article firstly analyzed the feasibility of converting a 660 MW ultra supercritical pure power generation unit to combined heat and power(CHP)by understanding the national energy conservation & emission reduction plan and the economic development of Suzhou & Wuxi and grasping the two main contradictions of district small thermal power shutting down and continued growth in demand for heating.Then the scheme of increasing new heat supply by modifying the draught fan is determined.At the same time,the boiler tail flue gas system can be optimized.Combining the original draft fan and the booster fan to one can simplify the flue structure,reduce the tail gas resistance and improve boiler’s efficiency.Main research contents of this paper are:1.As the capacity of new induced draft fans must match with the capacity of original draft fan and booster fan,this article compared the regulation method and dynamic selection of common induced draft fans in industrial applications.Because the actual demand of main modification goal was heat supply,the induced draft fans were designed to be regulated by static blade and driven by regenerative back pressure small steam turbine.2.According to the selected induced draft fan and the perspective that the induced draft fan was an important auxiliary of boiler,new control strategies and logic were designed respectively to adapt starting,normal operation,stopping and RB accident conditions.3.Industrial applications cannot be separated from economic analysis.The economic benefits of heat supply,the cost of induced draft fan transformation and the economic and environment advantages of the proposed method were analyzed. |
