燃煤机组耦合蒸气干化污泥能耗特性试验

Experiment of energy consumption characteristic in a coal-fired power unit coupled with steam desiccation sludge

煤与蒸气干化污泥耦合掺烧是一种大规模处置污泥的技术手段,而蒸气干化污泥掺烧对机组能耗的影响规律尚不明确。对某350 MW燃煤机组开展蒸气干化污泥掺烧性能试验,研究蒸气干化污泥对锅炉效率、厂用电率、汽机热耗率、机组能耗率等的影响。试验期间,湿污泥处理量设定为8.00 t/h,利用污泥干化机将湿污泥含水率从80%分别干化至60%、40%。结果表明,蒸气干化污泥耦合发电时,机组能耗率上升,其中,锅炉效率下降主要是因为排烟热损失和固体未完全燃烧热损失增加,汽机热耗率上升是由于干化蒸气消耗,机组厂用电率上升主要是由于风机系统电耗和脱硫系统电耗上升。污泥干化程度越高,锅炉效率下降幅度越小,汽机热耗率上升幅度越大,机组厂用电率上升幅度越小。利用蒸气将污泥含水率从80%干化至40%,机组供电燃料耗率略有下降,机组供电燃料耗率变化量从2.039 g/kWh降至1.904 g/kWh。当机组掺烧湿污泥时,锅炉效率下降和厂用电率上升是造成机组能耗率上升的主要因素;当机组掺烧蒸气干化污泥时,汽机热耗率上升是导致机组能耗率上升的关键因素。本研究为蒸气干化污泥耦合发电机组能耗评估提供了理论和数据支撑。

Co-combustion of steam desiccation sludge with coal is a technical measure for large scale sludge disposal,but the effect of steam desiccation sludge co-combustion on unit energy consumption characteristic is unclear.The performance test of co-firing coal and sludge dried by steam was conducted in a 350 MW coal-fired power unit.The effects of steam desiccation sludge on boiler thermal effi⁃ciency,steam turbine heat rate,auxiliary power consumption ratio,energy consumption rate were studied.During the test,the treatment amount of raw sludge was set at 8.00 t/h,and the moisture content of the raw sludge was dried from 80%to 60%and 40%respectively by sludge dryer.The results show that the unit energy consumption rate has an increasing trend when the power unit blends with steam desic⁃cation sludge.The decrease of boiler efficiency is mainly due to the increase of sensible heat loss in exhaust flue gas and unburned carbon heat loss in residue.The steam consumption during sludge desiccation leads to the increase of the steam turbine heat rate.The increase of power consumption of fan system and desulfurization system causes the increase of the auxiliary power consumption ratio primarily.The higher the degree of sludge drying is,the smaller the decrease of boiler efficiency is,the greater increasing extend of the steam turbine heat rate is,and the smaller increasing extend of the auxiliary power consumption ratio is.When the sludge moisture content is dried from 80%to 40%,the net fuel consumption rate reduces slightly,whose variation reduces from 2.039 g/kWh to 1.904 g/kWh.As the power unit blends with raw sludge,the decrease of the boiler thermal efficiency and the increase of the auxiliary power consumption ratio are the main factors causing the increase of energy consumption rate.As the power unit blends with steam desiccation sludge,the increase of the steam turbine heat rate is the key factor leading to the increase of energy consumption rate.This study provides the theory and data support for evaluating the energy consumption of the power generation coupled with steam desiccation sludge.