YANYing-ying,HUANGRong-min,WANGBao-long,et al.Comparison of Drying Processes of Coal?fired Generating Units Mixed with Municipal Sludge[J].China Water & Wastewater,2023,39(24):53-58.
Comparison of Drying Processes of Coal?fired Generating Units Mixed with Municipal Sludge
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第39卷
Number:
第24期
Page:
53-58
Column:
Date of publication:
2023-12-17
- Keywords:
- mixed burning of sludge in thermal power plant; direct drying; indirect drying; sludge disposal
- Abstract:
- Driven by policies, in recent years, the use of thermal power plants for sludge co-processing has gradually increased. Co-incineration of sludge in thermal power plants has become one of the important methods of domestic sludge disposal. The moisture content of the wet sludge transported by sewage treatment plants is generally about 80%, and its low calorific value is only 100-200 kJ/kg. If the wet sludge is directly sent to the coal?fired boiler of the power plant for combustion, it will reduce the furnace temperature and the boiler efficiency, and affect the normal combustion of the boiler. Therefore, it is more reasonable to dry the wet sludge to water content below 40% to improve the calorific value of the sludge before co-incineration. At present, the drying methods of mixed-combustion sludge in coal-fired power plants mainly include direct flue gas drying, indirect steam drying, and low-temperature belt direct drying. Among them, the investment and operation cost of the direct flue gas drying method is low, but the sludge blending ratio should be controlled. Otherwise, a large amount of flue gas needs to be extracted, which may affect the boiler thermal system, leading to an insufficient steam temperature. Therefore, the selection of the process needs to be comprehensively determined by combining the thermal calculation of the unit. The system of the indirect steam drying method is complicated with high investment and operation costs, but it has little influence on the operation of the boiler. A larger scale sludge drying and co-burning system can be set up. The low-temperature waste heat drying method has higher investment costs, lower operating costs, and a higher degree of dependence on the exhaust volume and temperature of the system, and the proportion of sludge blending should not be too high. Therefore, the process selection also needs to be combined with the thermal calculation of the unit.
Last Update:
2023-12-17