Based on a typical 600 MW coal-fired cogeneration unit

novel systems with integrated steam jet and external steam cooler are proposed. In novel system Ⅰ

the waste heat from exhaust steam is recovered through a steam jet

in which reheat steam is chosen as the working fluid. In novel system Ⅱ

an external steam cooler is used to reduce the superheat of the mixed steam and the heat load of the boiler. Based on EBSILON professional modeling

the system is analyzed considering the peak shaving performance and thermodynamic performance under the maximum heating condition(extracted steam for heating: 800 t/h) and variable conditions. Moreover

the effects of mixed steam pressure and heat exchanger end difference on the system performance are also investigated. The results show that

under the maximum heating condition

compared with those of the reference system

the heating capacities of the novel system Ⅰ and Ⅱ increase by 21.59 and 14.47 percentage points

and the power generation efficiencies are increase by 2.48 and 2.78 percentage points

respectively. With the heating load of 300 MW

the power load regulation ratios of the novel system Ⅰ and Ⅱ improve by 6.00 and 3.91 percentage points compared with the reference system

and the lower limits of generation reduce by 84.75 MW and 74.32 MW. The gross efficiency of the novel system Ⅰ and Ⅱ improve by 3.02 and 2.65 percentage points

respectively

when the mixing steam pressure is increased from 50 kPa to 85 kPa. With the upper temperature difference increasing from 1 ℃ to 9 ℃

the gross efficiencies of the novel system Ⅰ and Ⅱ decrease by 1.67 and 1.51 percentage points

respectively. The result can provide technical references for expanding heating capacity and deep peaking of coal-fired cogeneration systems.