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.