Integration of evaporative dryers into lignite-fired power plants: A review

Lignite is abundant and cost-effective fossil fuel for power plants. However, power plants firing lignite directly have low efficiency, which can be improved by pre-drying lignite. Various dryers have been developed to dry lignite, and evaporative drying technologies are commonly applied. Nevertheless, the evaporative drying is an energy intensive process. When evaporative dryers are integrated within power plants, the waste heat of power plants can be used to dry lignite, thereby increasing the efficiency of power plants. Many studies on the design and optimization of lignite-fired power plants integrated with evaporative dryers have been carried out. However, a review paper on this topic is unavailable. Therefore, this paper presents a literature review on the integration of evaporative dryers into lignite-fired power plants. System configurations of pre-dried lignite-fired power plants are reviewed and compared, and future research directions are proposed.