烟煤锅炉掺烧褐煤对机组安全经济性影响的研究

燃煤发电厂锅炉多煤种掺烧对机组安全经济运行具有十分重要意义。结合某电厂350 MW超临界烟煤锅炉掺烧蒙西褐煤的试验，分析验证了褐煤掺烧对降低标煤单价、提高锅炉效率、降低NO_x排放等主要指标的影响，取得较好的经济效益；通过掺烧试验探索机组在不同负荷下的最佳配风方案，提出锅炉CO质量浓度在线监测和燃尽风流量占比对低氮燃烧和锅炉效率的影响，一般控制CO质量浓度在200 mg/m³左右、燃尽风比率以7.0%～15.0%为宜，为解决低氮燃烧与燃烧效率之间的矛盾问题提供借鉴；通过优化燃烧调整试验、锅炉液体除焦剂注射试验以及改进锅炉冷灰斗光滑度等综合治理措施，有效缓解了锅炉受热面结焦问题，取得较好效果。可以为电站锅炉配煤掺烧和节能减排提供参考。

Study on the Impacts of Blending Lignite in Bituminous Coal Boiler on Unit Security and Economy

The coal-blend combustion using different types of coals in coal fired power plants is of great significance to the secure and economic operation of the unit. By taking account of the testing on the 350 MW supercritical bituminous coal boiler in a power plant, the positive impacts of lignite blending such as reducing unit price of standard coal, improving boiler efficiency and reducing NO_x emission are analyzed and verified and consequentially better economic benefits have been obtained. The optimal air distribution scheme under different loads is explored through combustion testing with blended coal. The on-line monitoring for the boiler CO concentration is proposed and the impact of burnout air flow ratio on low nitrogen combustion and boiler efficiency is also investigated, such that the CO concentration is generally maintained around 200 mg/m³ and the ratio of burnable air at the range of 7.0%~13.0%, which can be used as a reference to resolve the contradiction between low NO_x combustion and combustion efficiency. Moreover, comprehensive improvement measures have been taken such as improving the smoothness of the boiler's cold hopper, which effectively relieved the coking problem of the heating surface of the boiler and the results sound satisfactory. In summary, this paper has provided reference for coal blending as well as energy saving and emission reduction of utility boilers.