基于DPM模型的碱回收炉竹浆黑液雾化数值模拟研究

Numerical Simulation of Black Liquor Atomization in Alkali Recovery Boiler Based on DPM Model

关键词:  高固含量竹浆黑液  雾化性能  数值模拟  碱回收  DPM

Key Words:high solid content bamboo pulp black liquor  atomization performance  numerical simulation  alkali recovery  DPM

摘要:为高效回收高固含量竹浆黑液的化学品和热能，改善其雾化性能，本研究采用DPM（discrete phase model）模拟研究碱回收炉中高固含量竹浆黑液的雾化性能。通过建立的碱回收炉三维几何模型，采用Fluent软件对碱回收炉进行冷态流场模拟，研究了黑液黏度、雾化锥角及粒径范围对碱回收炉中黑液雾化效果、颗粒分布、熔融物垫层形成的影响。结果表明，增大黑液黏度对液滴破碎影响显著，而对于分散沉降的影响远不及雾化锥角及初始液滴尺寸；碱回收炉前墙上、下二次风之间区域存在结渣风险。液滴粒径大于0.5 mm时，黑液液滴主要受重力作用下沉至垫层，能有效减少气流的机械携带现象。

Abstract:In order to efficiently recover the chemicals and thermal energy of high solid content bamboo pulp black liquor and improve its atomization performance， DPM （ discrete phase model ） was used to simulate the atomization performance of high solid content bamboo pulp black liquor in alkali recovery boiler. And then， through the establishment of 3D model， the cold flow field of alkali recovery boiler was simulated by Fluent software. The effects of black liquor viscosity， atomization cone angle， and particle diameter on the atomization， particle distribution， and formation of melt cushion of black liquor in alkali recovery were investigated. The results showed that increasing black liquor viscosity had a significant influence on the droplet breakup， and the influence on the dispersion settlement was far less than that on the atomization cone angle and the initial droplet size. Additionally， slagging risk existed between upper and lower secondary air in front wall of alkali recovery boiler. When the droplet diameter was controlled greater than 0.5 mm， black liquid droplets mainly sank down to the cushion by gravity， and that could effectively reduce the mechanical carry of airflow.