反应路径和颗粒吸热对气化炉数值模拟的影响

Effects of reaction pathway and particle heat absorption on gasifier:a numerical study

气化工艺是实现劣质原油、非常规石油资源和煤炭高效清洁加工的有效途径,数值模拟是揭示气化炉内复杂流动反应行为的重要手段。为了考察挥发分反应路径和颗粒反应热吸收率对预测结果的影响,以奥里乳化油气流床气化过程为例采用欧拉-拉格朗日方法对气化炉进行数值模拟研究,均相反应和非均相反应过程分别通过有限速率/涡耗散反应模型和颗粒表面化学反应模型描述。结果表明,挥发分反应路径主要影响气化炉内气化反应的过程,如靠近喷嘴处的温度和组分分布,但对最终气化炉出口处的温度和组分分布影响相对较小。而由于原料中较低的固定碳质量分数以及较少的焦炭燃烧反应热,颗粒反应热吸收率对预测结果影响很小。

The gasification technology is an efficient way to process inferior crude oil,unconventional oil and coal with lower emissions,and numerical simuation is an important method to reveal the complex flow and reaction behavior in the gasifier. In order to evaluate the influence of volatile reaction pathway and particle reaction heat absorption ratio,the Orimulsion gasification process in an entrained-flow gasifier was simulated with Eulerian-Lagrangian method. The homogenous reactions and heterogeneous reactions were described by the finite-rate/eddy-dissipation model and particle surface reaction model,respectively. The simulation results demonstrate that the reaction pathway of volatile mainly affects temperature and species distributions in the near-nozzle region,while those at the outlet of the gasifier change only slightly. However,the effect of particle heat absorption ratio is almost negligible due to the lower amount of fixed carbon in the Orimulsion and the small reaction heat of coke combustion.