Thermal economic calculation and analysis for boiler flue gas pre-dried lignite-fired power generation system

Lignite Pre-drying can obviously improve the power generation efficiency of directly lignite-fired power plant, and rotary drying is the earliest application lignite pre-drying method. Therefore, a theoretical economic analysis model for boiler flue gas pre-dried lignite-fired power generation system was established, with which a case study on a 600 MW power generation system was conducted to analyze the factors influencing thermal efficiency. The results show that: lignite pre-drying with boiler flue gas dryer can reduce the coal consumption rate by 3.18 g · (kW · h)^-1 at bench mark condition listed; when the boiler temperature changes by every 10°C, the coal consumption rate will change 1.1 · g((kW · (h)^-1; the coal consumption rate will increase 0.6 g · (kW · (h)^-1 when 0.1 kg more water is dried out of lignite; The boiler flue gas dryer can increase thermal efficiency only when the dryer has enough thermal efficiency, and the coal consumption rate will increase by 0.1, 0.16, 0.23 g · (kW · h)^-1 when the dryer has 1% higher thermal efficiency at the degree of drying at 0.1, 0.2, 0.3kg · kg^-1.