摘要
天然气掺氢输送是实现大规模、远距离氢能转运的主要手段之一,但混氢天然气在放空过程中存在爆轰或爆燃的风险,对放空管壁施加的超压过大还会造成管壁破裂。因此,亟需明晰混氢天然气放空自燃与流场演化过程,进而量化放空管壁的一次超压。为此,利用计算流体力学方法数值模拟了混氢天然气管道放空自燃过程,对比分析了不同掺氢浓度条件下对自燃及压力波传播的影响规律,揭示了混氢天然气在阀门通道和放空管中的爆燃机制。研究结果表明:①高压气体在阀门通道内以压力波形式传播并不断地碰撞反射与叠加,形成马赫环结构,加热气体使温度升至自燃点,并触发自燃;②在阀门通道和放空管内均出现了爆燃现象,但压力波在放空管内能量迅速衰减,一段距离后温度大幅降低,气体不再燃烧;③掺氢比越大,压力波传递速度越快,自燃触发的时间越短,对放空管壁产生的一次超压也越大。结论认为,在确定的泄放压力与阀门开度工况下,降低掺氢浓度可有效减轻爆燃风险和减小壁面超压,实际工程中需结合输送经济成本和安全风险控制掺氢量在合理的浓度范围。混氢天然气管道放空自燃过程数值模拟分析取得的新认识有助于指导掺氢天然气管道的安全运行,将助力于绿色氢能的大规模混合输运。
Hydrogen-mixed natural gas transportation is one of the important ways for large-scale and long-distance hydrogen energy transportation.In the venting process of hydrogen-mixed natural gas,however,there are risks of detonation or deflagration,which exert excessive overpressure on the pipe wall,leading to its fracture.Therefore,it is in an urgent need to clarify the spontaneous combustion and flow field evolution process during the venting of hydrogen-mixed natural gas,so as to quantify the primary overpressure on the wall of the venting pipe.In this paper,the spontaneous combustion process during the venting of hydrogen-mixed natural gas pipeline is numerically simulated by using the computational fluid dynamics(CFD)method,the influence laws of different hydrogen concentrations on spontaneous combustion and pressure wave propagation are comparatively analyzed,and the deflagration mechanisms of hydrogen-mixed natural gas in valve channels and venting pipes are revealed.And the following research results are obtained.First,high-pressure gas is propagated in the form of pressure wave in valve channels.During the propagation,it undergoes continuous collision,reflection and superimposition to form Mach ring structure,which heats the gas to the spontaneous combustion temperature,resulting in spontaneous combustion.Second,the phenomenon of deflagration appears in valve channels and venting pipes.In venting pipes,however,the energy of pressure wave decays rapidly,resulting in a significant reduction of temperature and hence the disappearance of gas combustion.Third,the larger the hydrogen concentration is,the faster the pressure wave propagates,the shorter time it takes to trigger the spontaneous combustion,and the greater the primary overpressure on the venting pipe wall.In conclusion,with given discharge pressure and valve opening,reducing the hydrogen concentration can effectively reduce the deflagration risks and the overpressure on the pipe wall.In actual engineering,the hydrogen mixing volume shall be controlled within a reasonable concentration range based on transportation economic costs and safety risks.These new understandings provide useful guidance for the safe venting of hydrogen-mixed natural gas pipelines and the large-scale mixed transportation of green hydrogen energy.
作者
朱红钧
李佳男
陈俊文
粟华忠
唐堂
ZHU Hongjun;LI Jianan;CHEN Junwen;SU Huazhong;TANG Tang(Petroleum Engineering School,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Southwest Company,China Petroleum Engineering&Construction Corporation,Chengdu,Sichuan 610041,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2023年第9期149-161,共13页
Natural Gas Industry
基金
四川省杰出青年科学基金项目“混氢输送管道非线性耦合动力学行为与流固耦合机制研究”(编号:2023NSFSC1953)
中国石油集团工程股份有限公司支撑课题“含氢输气管道系统关键技术研究”(编号:2019ZYGC-01-09)
中国石油集团工程股份有限公司支撑课题“氢/氨储运及储存设备关键技术研究”(编号:2021ZYGC-03-01)。
关键词
混氢天然气
放空
爆燃
超压
自燃
数值模拟
Hydrogen-mixed natural gas
Venting
Deflagration
Overpressure
Spontaneous combustion
Numerical simulation
作者简介
朱红钧,1983年生,教授,博士研究生导师,主要从事多场多相耦合力学方面的教学与研究工作。地址:(610500)四川省成都市新都区新都大道8号。ORCID:0000-0001-5977-5028。E-mail:ticky863@126.com。
