An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable.

开发了一种基于生物质直接燃烧的先进热电联产系统，并证明了其可行性。新方案取代传统的单一热源（抽汽），将汽轮机抽汽、工厂冷凝器冷却水和给水预热系统低压给水集中用于区域供热。 . 因此，可以取得显着的节能效果，提高热电联产系统的整体效率。以 35 MW 生物质热电联产机组为例，研究了该新型系统的热力学和经济性能。一旦生物质进料速率和净热产量保持不变，由于推荐的升级，净发电量预计会增加 1.36 MW。因此，总系统效率和有效电效率分别提高了 1.23 和 1.50 个百分点。从能量和火用方面研究了性能增强的内在机制。经济研究表明，改造项目的动态投资回收期仅为 1.20 年，净现值为 5796.0 k$。总之，所提出的概念被证实是有利和有利可图的。