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随着石油开发逐渐向深海发展,海底管道蜡沉积已成为石油工业面临的一个严峻的流动安全保障问题。采用室内环道装置进行了2组不同温度、不同流速条件下不同沉积时间的蜡沉积试验,分析了含蜡原油沉积物密度、含蜡量、碳数分布、屈服强度等性质的变化情况。结果表明:1沉积物质量随时间延长而增加,且在开始阶段增加较快,而后变缓,沉积厚度是油壁温度与油流冲刷共同作用的结果;2沉积物密度、含蜡量、屈服应力随时间延长而增大,且随着时间延长,沉积物中大于临界碳数(在蜡沉积过程中,大于某一碳数的蜡分子可以向沉积物内部扩散,而小于这一碳数的蜡分子则只能从沉积物内部向外扩散,这一碳数称为临界碳数)的蜡分子含量增加,而小于临界碳数的蜡分子含量减小;3油温越高,更多大碳数的蜡分子可以扩散到壁面并沉积下来,峰值蜡分子向大碳数方向移动。(图12,表1,参18)
With the development of oil gradually developing to the deep sea, the wax deposition of submarine pipelines has become a serious problem of liquidity security for the petroleum industry. Two sets of wax deposition tests were carried out at different deposition temperatures and velocities under different flow velocities using indoor loop equipment. The changes of density, wax content, carbon number distribution and yield strength of waxy crude sediments were analyzed. The results show that: (1) the mass of sediment increases with time and increases rapidly at the beginning and then slows down. The sediment thickness is the result of oil wall temperature and oil flow scouring together. 2 The sediment density, wax content, yield The stress increases with time, and over time, the sediment is greater than the critical carbon number (in the wax deposition process, more than a certain number of carbon atoms in the wax molecules can diffuse into the sediment, and less than the carbon number Wax molecules can only be diffused from the inside of the sediment, the carbon number is called the critical carbon number) of the wax molecular content increases, while less than the critical carbon number of the wax molecular content decreases; 3 the higher the oil temperature, more The carbon wax molecules can diffuse to the wall and deposit, and the peak wax molecules move toward the larger carbon. (Figure 12, Table 1, reference 18)