甲烷高温自燃诱导过程实验与数值模拟研究

甲烷的转化在化工产业中具有举足轻重的地位与战略意义,近年来涌现的氧化偶联制烯烃等多种新型化工工艺涉及高温条件的甲烷-纯氧等体系的混合与反应过程,明确甲烷高温自燃诱导与爆炸规律是实现工艺安全设计与运行的前提,然而相关研究与基础数据仍较为欠缺。通过利用基于快速压缩装置的高温高压燃爆测试系统开展甲烷-纯氧等典型混合体系的自燃诱导过程研究,同时基于GRI-Mech 3.0机理的数值模拟方法进行了数值模拟研究。实验结果与数值模拟结果吻合较好,随着温度/压力的增加及氧气含量的下降,混合体系自燃诱导时间均缩短;燃料气中加入乙烷或氢气则会大幅缩短自燃诱导过程。对于多个工艺过程中涉及的低氧含量体系率先开展了研究,得到了不同当量比及温度条件下的典型体系自燃诱导时间,同时考察了惰性气的加入对于自燃诱导过程的延长作用。研究结果有助于深入理解甲烷自燃诱导机理,同时指导高温条件的甲烷转化工艺的本质安全化设计与爆炸防控。

Experiment and Numerical Simulation of Ignition Delay of Methane

The transformation of methane plays an important role in the chemical industry. In recent years,many new processes involving mixing and reaction process of methane-pure oxygen systemat high temperature were proposed. A deeper understanding of the ignition delay of methane at high temperature is important for the design of the process,while the related research is still lacking. In this study,the ignition delay of typical mixtures,such as methane-pure oxygen,was experimentally studied by based on a rapid compression machine,and numerically studied based on GRI-Mech 3.0 mechanism. The experimental results matched with the numerical simulation results well. With the increase of temperature/pressure and the decrease of oxygen content,the ignition delay time of the mixtures decreased,and theignition delay process was greatly shortened when ethane or hydrogen was added into the fuel gas. In this study,the low oxygen content systems involved in many chemical processes were investigated for the first time,and the ignition delay time of typical systems under different equivalence ratios and temperatures was obtained.The prolongation of the ignition delay process with the addition of inert gas was also investigated. The results contribute to the deeper understanding about the mechanism of the ignition delay of methane, and guide the inherent safer design andexplosion prevention for related processes under high temperature conditions.