定功率下太阳能辅助燃煤发电系统的热经济性分析

Thermal Economic Analyses of a Solar Aided Coal-fired Power Unit for Constant Power Output

基于热耗变换系数法分析了定功率条件下某300 MW太阳能辅助燃煤发电系统的热经济性。结果表明,代替某一级抽汽时,机组煤耗率的降低量与太阳能提供外热量的比值与该级抽汽热耗变换系数线性相关;相同热量代替#1抽汽相对代替#8抽汽,煤耗率降低量可提高82%,随着代替抽汽品质的下降,油–水换热器的传热面积提高了35%,而效率由95%降低到69%,单位面积的?收益由4.3 k W/m2下降到0.6 kW/m2,集热器的面积与造价在代替前6段抽汽(除氧器除外)时上升,在代替最末两级抽汽时降低,在代替第6段抽汽时达到最大值。单位煤耗率降低量所需的集热造价呈先上升后下降再上升的趋势,代替#1抽汽时最低。

The thermal economy of a 300MW solar aided coal-fired power unit was analyzed using the heat rate transformation coefficient method for constant power output. The results show that the ratio of coal consumption rate decrease to external solar heat is related to the heat rate transformation coefficient for the replaced bled steam. Comparing replacing #8 bled steam, the decrease in the coal consumption rate increases by 82% when #1 bled steam is replaced. As the replaced bled steam quality decreases, the oil-water heat exchanger＇s area increases by 35%, the exergy efficiency varies from 95% to 69% and the profit per unit area varies from 4.3 kW/m2 to 0.6kW/m2. The collector area and cost first increase to the maximum for the 6 stage bled steam and then decrease with the decreasing bled steam quality. The ratio of the collector cost to the decrease in the coal consumption rate increases then decreases and increases again, and the ratio is the minimum when the 1 stage bled steam is replaced.