CFD simulation of entrained-flow coal gasification: Coal particle density/sizefraction effects
CFD simulation of entrained-flow coal gasification: Coal particle density/sizefraction effects
复制标题
DOI：
10.1016/j.powtec.2010.03.029
复制
发表时间：
2010-10
影响因子：
5.2
通讯作者：
Andrew Slezak;J. Kuhlman;L. Shadle;James Spenik;S. Shi
中科院分区：
文献类型：
--
作者：
Andrew Slezak;J. Kuhlman;L. Shadle;James Spenik;S. Shi
采用计算流体动力学（CFD）方法对工业规模的两级上流式和单级下流式旋流气化炉进行了模拟，研究了模拟煤颗粒密度和粒度变化的效果。一个先前开发的气化CFD模型进行了修改，占煤颗粒的密度和尺寸分布，从一个典型的棒磨机生产。后处理工具被开发用于分析颗粒壁冲击性能。对于两级上流式气化炉，提出了三种不同的模拟：两种（情况1和情况2）使用相同的脱挥发分和焦炭转化模型从文献中，而情况3使用不同的脱挥发分模型。案例1和案例3解决方案使用匹兹堡#8煤层煤（d=108μm，SG=1.373）的平均特性，而案例2是通过注入和跟踪PSU同事作为当前工作的一部分获得的28种不同煤颗粒密度和尺寸质量分数的所有系列来获得的。使用两个脱挥发分模型（情况1和情况3）的模拟一般是合理的协议。在单一密度溶液和密度/大小分区溶液（情况1和情况2）之间观察到差异。的密度/尺寸分区的解决方案预测名义上10%少CO和超过5%以上的H2在产品气流中的体积。对于较大的密度/尺寸分数，这两种解决方案之间的颗粒停留时间和轨迹不同。对于分配的溶液，固定碳转化率高4.3%。颗粒与壁面的碰撞速度变化不大。两级上流式气化炉几何形状的网格独立性研究表明，比较研究中使用的网格足以预测出口气体成分和壁面冲击速度。使用来自SRI国际加压煤流反应器（PCFR）的匹兹堡#8煤在30个大气压下的实验数据进行的验证研究表明，气化和燃烧情况下具有足够的一致性，但热解情况下的一致性较差。单级下流式气化炉的模拟产生的出口气体组合物是在合理的协议与公布的数据。
Computational Fluid Dynamics (CFD) simulation of commercial-scale two-stage upflow and single-stage downflow entrained-flow gasifiers was conducted to study effects of simulating both the coal particle density and size variations. A previously-developed gasification CFD model was modified to account for coal particle density and size distributions as produced from a typical rod mill. Postprocessing tools were developed for analysis of particle–wall impact properties. For the two-stage upflow gasifier, three different simulations are presented: two (Case 1 and Case 2) used the same devolatilization and char conversion models from the literature, while Case 3 used a different devolatilization model. The Case 1 and Case 3 solutions used average properties of a Pittsburgh #8 seam coal (d=108μm, SG=1.373), while Case 2 was obtained by injecting and tracking all of the series of 28 different coal particle density and size mass fractions obtained by colleagues at PSU as a part of the current work, for this same coal. Simulations using the two devolatilization models (Case 1 and Case 3) were generally in reasonable agreement. Differences were observed between the single-density solution and the density/size partitioned solution (Case 1 and Case 2). The density/size partitioned solution predicted nominally 10% less CO and over 5% more H2by volume in the product gas stream. Particle residence times and trajectories differed between these two solutions for the larger density/size fractions. Fixed carbon conversion was 4.3% higher for the partitioned solution. Particle–wall impact velocities did not vary greatly. Grid independence studies for the two-stage upflow gasifier geometry showed that the grid used in the comparison studies was adequate for predicting exit gas composition and wall impact velocities. Validation studies using experimental data for the Pittsburgh #8 coal from the SRI International pressurized coal flow reactor (PCFR) at 30 atmospheres indicated adequate agreement for gasification and combustion cases, but poor agreement for a pyrolysis case. Simulation of a single-stage downflow gasifier yielded an exit gas composition that was in reasonable agreement with published data.