The effects of water vapor on the adiabatic flame temperature, premixed flame temperature and laminar premixed flame velocity of methane combustion were studied by using Chemkin 17.0, and the effect of water vapor on the chain reaction process of methane combustion was also studied. The results show that with the increase of water vapor content, the temperature of methane flame and premixed laminar flame speed decrease, and the concentration of H,O,OH free radicals is also reduced, while the proportion of OH free radical is raised, leading to the dominance of reactions transmitted by OH free radicals. The addition of water vapor changes the chain reaction of methane combustion, enhances the reaction of CH3 to CH2(s),CH2(s) to CH2,CH2 to CH,CH to CH2O, and enhances the reaction of CH3 to CH3O,CH3O to CH2O at the same time.

Three⁃dimensional finite element model of buried casing is established using ANSYS software. Through laboratory tests, the relationship between the stress within the center of buried casing and the load on the ground, and the stress distribution in the direction of casing length under different loads is analyzed,respectively. Finally, a three⁃dimensional finite element model is established according to several casing cases in an oilfield. The magnitude of the load on the ground is obtained when the casing reaches the yield strength. The research results can provide a certain reference for the safety protection of pipelines and casing.

Under different temperature and different stress conditions, the creep experiment of polyurethane foam was carried out, and the creep constitutive equation of polyurethane foam under high temperature was obtained by fitting the obtained creeptime curve with Modified Time Harding model. Comparing the steady state creep rate fitted by model with the steady state creep rate measured by experiment, it is found that the creep property of polyurethane polymer has an important relationship with temperature and stress level. As the temperature and the stress level increases, the creep behavior of the material is more pronounced. The creep curve at high temperature is divided into two phases. In the first phase, the creep rate is larger and the creep rate gradually decreases with time. In the second phase, the creep rate is small and remains basically constant. Modified Time Harding model can better predict the creep rate of polyurethane materials under high temperature conditions.

Due to the similarity of the routing between HVDC transmission lines and buried pipelines, the local pipelines inevitably enter the HVDC transmission interference zone. In order to study the law of interference and mitigation of HVDC grounding electrode on buried pipeline, boundary element software was used to calculate the effectiveness of various mitigation methods including anti-corrosion coating, the distance between the pipeline and the grounding electrode, insulating joints and zinc ribbon. The results indicated that the smaller the coating breakdown factor was, the more concentrated the interference current was , and the higher the local corrosion risk was. After installing the insulating joints, the strongest interfered section of pipe was alleviated, while the interference of the other section of pipe was aggravated. The protection range of the zinc ribbon was equivalent to the length of the zinc ribbon. Finally, the paper put forward the comprehensive protection measures which included insulating joints, cathodic protection and zinc ribbon.

People around the world have paid more and more attention to the problem of oil volatilization, because of the enforcement of laws on energy saving and lots of accidents caused by oil diffusion. It is important for people to find the laws of oil volatilization. That could reduce the oil diffusion during its transportation and storage, decrease the pollution, and prevent the occurrence of related accidents. Data of oil and gas diffusion in tank is obtained using the model of VOF that comes from CFD by considering the influence of wind speed, wind direction and tank type. It is also a good choice to use UDF as the source of the simulation analysis. The results show that wind speed has a great effect on oil evaporation. And the wind direction that perpendicular to the wall of the tank has evident effects. According to the study on evaporation loss of oil, the petrochemical plants must take some effective measures to reduce the oil diffusion, and reduce the risk of explosion. 