On-line Cleaning Of Heat Exchanger Fouling In Atmospheric And Vacuum Unit

The fouling formed in the process of heat transfer has affected the normal operation of the equipment seriously, and causes huge waste of energy. The comprehensive needs which come from economy, environmental protection and energy saving pose new challenge on the cleaning of the equipment fouling. In this research, compound fouling which formed in the heat exchanger in the atmospheric and vacuum unit is the object of study. Based on the formation process of the compound fouling in the shell side of the heat exchanger and the mechanism of dissolving the fouling, the homemade cleaning agents were studied. The on-line cleaning device was designed. In order to get a reasonable power for the cleaning device, the dynamics calculation of the internal flow field about the cleaning liquid will be done. The main works are as follows:(1) The formation and influencing factors of fouling were studied. Based on those, the effective measures to prevent and control the formation of fouling were present. The chemical cleaning mechanism and influencing factors were also studied. Make sure that concentration of chemicals, temperature and velocity are the key of on-line cleaning cycle.(2) Design process and equipment for on-line cleaning. The equipment includes electric heating, U-tube heat exchanger, store tank, pump and so on. Given on the structure size of each part, three-dimensional model was built by Solid works.(3) Analysis the flow field of shell side by FLUENT. Based on the minimum threshold theory (when Reynolds number is larger than25000, mechanical effects of fluid on the dirt could show obviously) and Esso formula, matching power is discussed.The completion of this study not only provides the experimental data for clearance, but also provides a digital guide in theory on the power design of on-line cleaning device. The research has an important guiding significance on the development of cleaning petrochemical plant.