Study On The Energy-saving And Optimization Of Ultra-supercritical Double Reheat Coal-fired Power Plant

Ultra-supercritical double reheat technology is one of the more efficient and low-pollution thermal power generation methods,and has become an important choice for the development of high-capacity and high-parameter thermal power units.However,on the one hand,on the variable work condition,power generation efficiency is low and available hours of the double reheat unit decreases in actual operation;on the other hand,because of two-stage reheat and high steam parameters,the superheat of the extraction is too high,which leads to a large irreversible loss of the reheat system and reduces the energy saving advantage of the secondary reheat unit.At present,the research on the energy consumption distribution of the double reheat unit under variable workloads and the method of reducing the superheat of the reheat extraction steam to reduce the irreversible loss,which has become an important content of the energy saving optimization research of the ultra-supercritical double reheat unit.This paper,based on the 660 MW ultra-supercritical double reheat unit as the research unit of reference,uses the commercial software Ebsilon Professional simulation calculation was carried out on the unit.Using the method of fuel specific consumption to study the total energy consumption distribution characteristics on the variable condition,the additional equipment consumption of different devices is acquired,which could assist to locate the part where the energy consumption is more and dig potential of energy saving.In view of the problems such as the limited series of cooling reheat extraction and the unsatisfactory heat transfer effect in the generally adopted way of adding two-stage outer steam cooler to reduce the superheat of extraction in the double reheat unit,the four novel schemes are put forward which integrated regenerative steam turbine with unit.The analysis of thermal performance is conduct,including energy consumption,superheat of extraction and so on,and the optimal system configuration scheme is obtained.In the end,thermal performance on the variable work-condition and the analysis of technical economy has been studied in this paper about the novel scheme which has the most advantageous thermal performance of four proposed schemes,and the results shows the novel systems have a great competition advantage when compared with the reference system.The results of study will provide theoretical guidance of energy-saving optimization of double reheat ultra-supercritical units.