In view of the influence of different factors on the leakage and diffusion of hydrogen?doped natural gas pipelines in the pipe gallery, the leakage and diffusion model of hydrogen?doped natural gas pipelines in the pipe gallery was established by numerical simulation software, and the influence of factors such as hydrogen doping ratio, pipeline pressure，leakage hole size and the model of ventilation on the gas diffusion process was studied. The results show that the hydrogen blending ratio can affect the mass transfer ability of hydrogen?doped natural gas, and the higher the hydrogen blending ratio, the faster the diffusion rate of hydrogen?doped natural gas. The pipeline pressure and leakage hole size mainly affect the leakage gas diffusion by affecting the initial kinetic energy and leakage volume of the leakage gas, and the leakage gas diffusion range becomes larger with the increase of pipeline pressure and leakage hole size. The ventilation mode plays a dominant role in the distribution of leaked gas in the pipe gallery, and the ventilation frequency is inversely proportional to the height of the leaked gas jet.

The effects of a single emulsifier octylphenol ethoxylate 10 (OP?10) and its compounding system on emulsion stability, rheology and the effect of organic bases on the interfacial tension were investigated. The results show that the optimal binary composition is as follows: The mass fraction of OP?10 is 1% and the mass fraction of sodium oleate (YSN) is 0.6%.The optimum compounding method can produce stable emulsion with thick oil, and the viscosity can be reduced from 1 168.22 mPa?s to 57.57 mPa?s, with the viscosity reduction rate of 91.03% and the water separation rate of 21.33%. The organobase triethanolamine (TEOA) can reduce the interfacial tension of the compounded system to the 10^-2 mN/m level.

Using the synergistic effect of surfactant mixture to reduce oil?water interfacial tension and crude oil viscosity is an important method to improve oil recovery in recent years.The content of each component of crude oil produced from each oil field is different, so it is necessary to screen the suitable surfactant according to the component content.In this paper, the interfacial tension and emulsifying properties of sodium dodecyl benzene sulfonate (SDBS) and lauryl glucoside (APG1214) in Liaohe crude oil were studied by rotating drop interfacial tensiometer and bottle test method. The interfacial tension was studied by changing different compounding ratios, salinity and pH value, and the viscosity of the emulsion was measured by viscometer.The results show that the interfacial tension between oil and water can be reduced and the stable heavy oil emulsion can be formed by adding proper amount of inorganic salt in combination of surfactant.

To study the influence of hydrogen mixing ratio on the leakage of natural gas pipelines, a mathematical model for the leakage and diffusion of directly buried high?pressure hydrogen mixed natural gas pipelines was established based on computational fluid dynamics theory and numerical simulation method.The leakage status, volume fraction distribution of hydrogen mixed gas,and the distribution of soil pressure and gas velocity around the pipeline were analyzed under different hydrogen mixing ratios.The results show that with the increase of hydrogen mixing ratio, the explosion radius of hydrogen mixed gas in the atmosphere will gradually decrease,and the range of high?pressure area around the pipeline will gradually decrease,and the gas flow rate at the leakage port will gradually increase.When the hydrogen mixing ratio is 30%,the explosion radius in the atmosphere is reduced by 43%,and the gas flow rate at the leakage port is increased by 68%.This provides a theoretical reference for the safety and emergency repair of hydrogen?doped natural gas pipelines and has important practical significance for promoting the large?scale application of hydrogen?doped natural gas.

To investigate the structure?function relationship of novel extended surfactants and the mechanisms of reducing interfacial tensions (IFTs) at oil?water interface, the interfacial tension values of 13?P series 13?P（I?C₁₃（PO） _x S,x=5,10,15,20）with different concentrations of NaCl and n?hexane to n?tetradecane at fixed concentration were measured by rotary drop interfacial tension meter. The result indicates that at higher numbers of PO（x=15,20), the n_min values become higher with increasing concentration of NaCl. At lower numbers of PO（x=5,10), the n_min values become lower with increasing concentration of NaCl. It reflects two mechanisms on reducing IFTs: Hydrophilic lipophilic equilibrium effect and hydrophilic hydrophobic group in size matching effect, both of which work together, and the size matching plays a crucial role at lower numbers of PO and HLB dominates at higher numbers of PO.

This paper proposed a method to improve the safety of shell and tube heat exchangers by adding a heat insulation layer at the inlet end of the heat exchange tube. Based on the SIMPLE algorithm, the transient change model of end temperature difference of three?dimensional shell and tube heat exchanger was established, and the effects of the changes of insulation thickness and insulation material on the safety of heat exchanger were compared. The results show that the temperature difference between the two sides of the heat exchange tube is significantly reduced when the pipe end insulation layer is installed, regardless of the material of the pipe end insulation layer; The greater the thickness of the insulation layer at the pipe end and the thermal conductivity of the insulation material, the greater the reduction of temperature difference, instantaneous thermal shock stress and temperature difference thermal stress on both sides of the heat exchange tube, and the higher the safety of the heat exchanger; When the thickness of the pipe end insulation layer is 247.5 mm and the thermal conductivity is 2.090 0 W/(m?K), the maximum instantaneous temperature difference on both sides of the heat exchange pipe can be reduced by 10.1%, the maximum temperature difference can be reduced by 12.5% during stable operation, and the instantaneous thermal shock stress and temperature difference thermal stress can be reduced by 10.1% and 12.5%.

The effect of the compound system of IAEC?1306H (Isotridecyl alcohol polyoxyethylene ether carboxylic acid solution), alcohol solution and alkali agent on the viscosity of heavy oil was studied. The results show that under the same mass fraction conditions, maltitol has better viscosity?reducing effect on heavy oil than sorbitol, and NH₃·H₂O water has better viscosity?reducing effect on heavy oil than IAEC?1306H and alcohol solution.The mmonia water and IAEC?1306H have similar on the viscosity reduction effect of on heavy oil.With the increase of the volume fraction of NH₃·H₂O and the mass fraction of IAEC?1306H, the viscosity of the heavy oil gradually stabilizes.In the binary compound system, the binary system formed by compounding sorbitol and maltitol with IAEC?1306H respectively has the same viscosity reducing effect on heavy oil. And due to the nature of the alkali agent, the compounding of the alkali agent and IAEC?1306H is more conducive to the viscosity reduction of heavy oil.In the ternary compound system, the ternary system formed by the combination of NH₃·H₂O, maltitol and IAEC?1306H has a better viscosity?reducing effect on heavy oil, with a viscosity?reducing rate of more than 96%, and the dosage of NH₃·H₂O, IAEC?1306H, and maltitol are used less.

Erosion corrosion often occurs in oil pipeline system. The main reason for erosion corrosion is the impact of particles on the wall. DPM model was used to study the erosion effect of solid particles on the pipe wall, analyze the flow characteristics of π?shaped pipe, and study the influence of fluid velocity, particle mass flow rate, particle diameter and density on the erosion corrosion rate of the pipe. The simulated results show that the erosion corrosion of π?shaped pipe is the most serious at the elbow. The maximum erosion corrosion rate increases with the increase of fluid velocity and particle mass flow rate. As the particle diameter and density increase, the erosion effect is weakened.