摘要
对天然气在管道内发生燃烧事故的原因进行分析,重点分析引起天然气在管道内着火的3个因素。从天然气的氧化燃烧机理出发,通过理论计算及现场试验的方法,计算出天然气-空气混合物最易燃烧的体积分数为8.7%。在此体积分数下,从能量平衡角度出发,提出天然气最小点火能量半经验关系式,计算最小点火能量,通过热渗透模型对天然气-空气混合物的燃烧过程进行研究。计算结果表明:通过单纯的绝热压缩,把天然气从0.1 MPa压缩到2.8 MPa,天然气-空气混合物的温度不能达到甲烷的自燃温度;天然气在燃气轮机进气管道内燃烧的主要原因为天然气管道内进入可燃物质柴油,在近似绝热压缩过程中,混合气体温度升高,达到可燃物质自燃点,从而引起管内天然气-空气混合物持续燃烧,直至氧气耗尽。根据现场实际情况,提出燃气进气系统改进方案,供同类型燃气进气系统设计及安装时参考。
Causes for natural gas combustion accidents in pipelines were analyzed from three factors.Analyzing from the oxidation combustion mechanism of natural gas,the volume fraction of the most flammable matter in natural gas-air mixture was obtained through theoretical calculation and tests on site,which was 8.7%.The semi-empirical function of the minimum ignition energy for natural gas with this volume faction was proposed based on energy balance.The minimum ignition energy was used in studying natural gas-air mixture combustion process,purely based on thermal penetration model.The calculation results showed that compressing natural gas from 0.1 MPa to 2.8 MPa only by adiabatic compression,the temperature of the natural gas-air mixture could not reach the self-ignition temperature for methane.The main reason for the natural gas combustion in the gas turbine inlet pipe was combustible materials,diesel fuel.During the approximate adiabatic compression process,the temperature of the mixed gas rose and reached the self-ignition point of the combustible material,diesel fuel,which caused the natural gas-air mixture continuous combustion in pipelines until the exhaustion of oxygen.According to the actual situation on site,an improvement scheme for gas intake system is proposed for the design and installation of the same type gas intake system.
作者
葛鹏
封坤
程佳其
周康伟
GE Peng;FENG Kun;CHENG Jiaqi;ZHOU Kangwei(China Energy Engineering Group Northwest Electric Power Test Research Institute Company Limited,Xi’an 710000,China)
出处
《华电技术》
CAS
2019年第10期53-59,共7页
HUADIAN TECHNOLOGY
关键词
天然气
管内燃烧
最小点火能量
能量平衡
热渗透模型
近似绝热压缩
自燃
nature gas
combustion in pipelines
minimum ignition energy
energy balance
thermal penetration model
approximate adiabatic compression
self-ignition
