燃氢水泥分解炉的数值模拟

Numerical simulation of cement calciner using hydrogen as an alternative fuel

氢气具有热值高和零碳排放的特点,是受到广泛关注的清洁能源,将其作为替代燃料用于水泥熟料煅烧时,可减少化石燃料的使用量,具有很好的碳减排效益。但受限于经济性和安全问题,氢气在水泥熟料煅烧中的应用尚属起步阶段。本文采用计算颗粒-流体力学数值模拟方法,对水泥分解炉内生料分解和燃料(煤和氢气)燃烧过程进行了数值模拟,首次揭示了掺氢燃烧时(热替代率0~100%),分解炉内碳酸盐分解、温度、CO_(2)和NOx排放的变化规律。以氢气为替代燃料时,三次风管附近容易产生局部高温,尤其是TSR较高的时候,存在损伤相关区域保温材料的风险;当氢气用量过高时,会存在难以燃尽的情况;当TSR=5%、10%、20%、50%和100%时,分解炉出口CO_(2)排放量依次可减少0.74 t/h、1.37 t/h、13.38 t/h、25.58 t/h和50.77 t/h。

As an industrial fuel,hydrogen has the advantages of high calorific value and zero carbon emissions,and is a kind of clean energy that has received widespread attention.When used as an alternative fuel for the calcination of cement clinker,hydrogen shows excellent carbon emission reduction benefits because of the reduction of fossil fuel usage.However,due to economic and safety issues,the application of hydrogen in the calcination of cement clinker is still in its infancy.In this paper,numerical simulation based on the computational particle-fluid dynamics is conducted to simulate the decomposition of raw meal and the combustion of fuel(coal and hy⁃drogen)in cement calciner.For the first time,the variation tendency of carbonate decomposition,temperature,CO_(2),and NOx emissions in cement calciner are revealed when burning hydrogen(thermal substitution rate,TSR:0~100%).When using hydrogen as the alterna⁃tive fuel,local hot spots will occur near the tertiary air duct,resulting in damaging the insulation materials and thermal NOx,especially when the TSR is high.It will be difficult to burn completely when 100%hydrogen is used.The CO_(2) emissions can be reduced by 0.74 t/h,1.37 t/h,13.38 t/h,25.58 t/h and 50.77 t/h respectively with a TSR of 5%,10%,20%,50%,100%.