Pressure and temperature increase of LPG in a thermally coated pressure vessel exposed to fire: Experimental and model results

Damage caused by incidents with transport tanks with compressed liquified gas is amongst the most extreme that can be encountered with transport vessels. This is particularly the case with the Boiling Liquid Expanding Vapor Explosion (BLEVE), which may occur if such a tank is exposed to fire for a prolonged period. Therefore, the local Dutch LPG transport sector adopted a thermally insulating tank coating as a ‘standard outfit’ for their tank trailers, with the aim to delay a BLEVE for a sufficiently long period for emergency services to take appropriate measures and for people near the accident location to be evacuated. On a European scale however, no consensus has been reached on the cost-benefit of such measures.With the current drive towards “greener” and renewable energy sources, this issue has regained attention with alternative fuels such as LNG, CNG and Hydrogen and a need was felt for (better) theoretical models and experimental data concerning the behavior of transport tanks carrying these substances.In this paper a new tank thermal (equilibrium) model is described to predict pressure and temperature behavior of a multi layered, thermally insulated tank containing a compressed liquified gas exposed to heat. Results are compared with data of three bonfire experiments, in which 3 m³ tanks, filled for ca. 50% with LPG were exposed to fire. A good match between modelled and experimental pressure and temperature evolution in time could be obtained using a constant value for the thermal conductivity of the insulation layer. The modelling showed that the thermal insulation value is crucial for an accurate prediction of these parameters as well as the opening time for a pressure safety valve. As relevant temperatures may cover a very wide range (from cryogenic in LNG-tanks to over 1000 °C in a fire) knowledge of the thermal (and physical) behavior of the insulating layer over a large temperature range is essential.The same holds for the behavior of the PRV when subjected to fire. Extreme temperatures may also lead to deviating behavior from what is expected based on the initial settings.     

石油化工物料长输管线安全设计问题探讨

针对石油化工物料长输管线设计、审查过程中存在的问题进行了较为全面的分析,并提出了解决的方法,为进一步完善相关工程设计规范和如何有效地执行这些规范提供了实例,给同类工程提供有益借鉴。     

EFE-1100回转切换定位反吹风旁插扁袋除尘器在济钢原料厂汽车受料槽除尘系统的应用

EFE-1100旁插扁袋除尘器采用一个电动回转切换阀实现对各室依次进行定位反吹清灰。具有结构紧凑、机构简单、组装灵活、换袋方便、维护量小、控制自动化、运行可靠等特点,在原料厂汽车受料槽、一炼铁铁水罐间、第二烧结厂原料场等除尘系统中广泛应用,均取得了明显的效果,以原料厂为例将除尘器的设计及应用做详细的介绍。     

高炉贮矿槽除尘系统的设计与分析

文章以河南青浦合金材料有限公司2座580m^3高炉贮矿槽除尘共用一台1450m^2的长袋低压脉冲袋式除尘器的总体设计方案为例,结合实践分析了高炉贮矿槽除尘系统的特点,总结并改进了整个除尘系统中的设计缺陷和制作结构,使该除尘系统得到了成功应用。     

城市燃气管道地震安全控制演示系统

介绍了一种用于展示城市燃气管道地震安全控制系统工作机理和控制效果的演示系统。对演示系统地震阀门的原理和性能作了阐述,对演示系统的组成、工作原理和效果做了较为详细的介绍。该系统可用于科普场馆或相关单位介绍城市燃气管道地震紧急处置的原理,系统已在唐山市地震博物馆安装应用。     

蒸汽系统安全阀泄漏原因分析及改进措施

从技术及管理两方面分析了蒸汽系统安全阀泄漏的原因,提出了预防措施。     

An improved gas chromatography for rapid measurement of CO2,CH4 and N2O

Combining improved injector, gas line and valve-driving modules, a GC equipped with FID and ECD, could simultaneously measure CH4, CO2 and N2O in an air sample within 4 min. Test results showed that the system has high sensitivity, resolution and precision; the linear response range of the system meets the requirement of in situ flux measurements. Thus, the system is suitable for monitoring fluxes of main greenhouse gases in terrestrial ecosystem since it is easy to use, efficacious, stable and reliable to collect data.     

气举压缩机止回阀的改进

分析现用摆臂式止回阀在多年的使用中暴露出的关闭不严、阀板脱落、密封损坏等问题,针对气举压缩机气流脉动的特点,应用压缩机气阀原理,对气举压缩机使用的摆臂式止回阀进行了改进,大大提高了设备运行的安全性.     

滑套式井下安全阀设计及动态特性分析

为防止井喷、保证油气井正常生产,设计了1种滑套式井下安全阀,对其结构、控制方式和工作原理进行了介绍;采用有限元的方法对井下安全阀由开启到关闭的动态过程进行模拟,在滑套阀不同倒角情况下,对滑套阀内部流场特性和所受压力的变化规律进行分析。分析结果表明,在滑套阀关闭过程中流体最大速度达到275 m/s,滑套阀所承受最大压力超过40 MPa;流体速度和滑套阀所受压力都随着滑套阀开度的减小而增大,随滑套阀倒角的增大而减小。此滑套式井下安全阀采用压力脉冲控制方式,液压管线只需要传递压力脉冲信号,杜绝了因管线泄漏而造成的井下安全阀失效。同时,驱动方式改为电机驱动,直接控制滑套式阀门的开合,反应迅速,提高了安全性和可靠性,具有较好的实用价值。