水煤浆气化炉洗涤室内气体穿越液池过程颗粒分布的数值模拟

Numerical Simulation of Particles Distribution in Process of Gas Crossing Cistern in Scrubbing Chamber in Coal Water Slurry Gasifier

水煤浆气化炉洗涤室内含固态渣的合成气在穿越液池的过程中得到了洗涤净化。研究气化炉洗涤室内颗粒的运动及其分布规律,对提高合成气的洗涤效果具有重要意义。将计算流体力学方法、直接模拟蒙特卡洛方法相结合,在Euler-Lagrangian框架下建立三维数学模型,对气化炉洗涤室内的气液固三相流动进行了模拟计算。在实验验证的基础上,揭示了不同运行工况、不同粒径颗粒以及不同颗粒级配下的颗粒数密度分布特性。研究表明:沿洗涤室高度方向颗粒数密度分布总体呈下降趋势,在洗涤室液池内颗粒数密度分布存在波动形式;大粒径颗粒在液池中易于沉降,对其具有较好的洗涤分离效果。而小粒径颗粒的沉降性较差,易产生悬浮;颗粒级配的改变对洗涤室液池内颗粒数密度分布影响较大。

The syngas passing through cistern was scrubbed in the scrubbing chamber of coal water slurry gasifier. The particles movement and distribution rules in scrubbing chamber were studied, which was significant to improve syngas scrubbing effect. The gas-liquid-solid flow in scrubbing chamber was simulated by a combined method of the computational fluid dynamics with the direct simulation Monte Carlo method in the frame of Euler-Lagrangian approach. On the basis of compare with the experimental data in literature, the effects of operating conditions and size grading on particle number concentration distribution in scrubbing chamber were revealed and studied. The results show that the particle number concentration increases along height of scrubbing chamber, but the particle number concentration distribution in the cistern becomes wave-shaped. The large particles ease to settle down in the cistern. However the small particles ease to suspend in contrast. With changing the particles size grading, the particle number concentration can be changed in the cistern of scrubbing chamber.