蓄热式热力燃烧室结构模拟优化与应用效果分析

采用1套60000 m3/h蓄热式热力燃烧炉(regenerative thermal oxidizer, RTO)处理工业VOCs废气,装置投运后出现废气停留时间不足、净化气VOCs浓度波动大的情况,采用流场数值模拟分析后发现,系由RTO燃烧室结构设计不合理造成。为解决此问题,采用数值模拟优化燃烧室结构,确定设计和改进参数,将结构优化结果应用于RTO装置,设置斜板和挡墙,延长收窄通道。模拟结果和实际应用表明:结构优化有效改善了进气侧燃烧室内流场分布的均匀性,提高了燃烧室内整体湍流动能水平,扩大了燃烧室内的高温区域范围;在实际运行中,优化后净化气VOCs浓度波动大幅降低,不同运行阶段的浓度差异仅为4 mg/m3左右,缩小了78%,VOCs去除效率(RE)长期保持在99.5%以上,RTO燃烧室的结构模拟优化与应用实现了工业VOCs废气的高效净化,为未来RTO装置的结构优化设计提供参考。

ANALYSIS ON STRUCTURAL SIMULATION,OPTIMIZATION AND APPLICATION EFFECT OF A REGENERATIVE THERMAL OXIDIZER

A 60000 m3/h regenerative thermal oxidizer(RTO) was used to treat the VOCs exhaust from industrial sources. It was found that the residence time of exhaust in the RTO was insufficient during the RTO was running. The concentration of VOCs in the purified gas fluctuated greatly. Numerical simulation of flow field of the RTO showed that the structure design of combustion chamber of the RTO was unreasonable. In order to solve this problem, in this work, the structure of the combustion chamber was optimized by numerical simulation. RTO design and improvement parameters were determined and applied. Inclined plates and retaining walls were installed in the combustion chamber of the RTO. The narrowed channels of the combustion chamber were extended. The results of the simulation and practical application showed that the structure optimization could effectively improve the uniformity of the flow field distribution at the inlet side of the combustion chamber. The overall turbulence kinetic energy in the combustion chamber was increased. The high temperature area in the combustion chamber was expanded. The fluctuation of the VOCs concentration of the purified gas was greatly reduced in practical optimized operation. The concentration differences between different operation stages were reduced by 78%, as low as about 4 mg/m3. In addition, the removal efficiency(RE) of VOCs remained above 99.5%. The highly efficient purification of industrial VOCs exhaust was realized through the structural simulation, optimization and application of RTO's combustion chamber. It provides strong support for the structural optimization design of RTOs in the future.