Study On The Anti-fouling Characteristics Of Assembled Rotors

The heat transfer equipment as a key equipment in the petrochemical industry, its heat transfer performance impact energy efficiency, economic and environmental greatly. And fouling is the significant factor of thermal performance of heat exchanger. So we need to develop a technology which can anti-fouling and enhance heat transfer urgently.In this paper, the research progress of heat exchanger's fouling mechanism and fouling countermeasure at home and abroad is summarized. In addition, the research status of inserts technology, including spiral spring,twisted tape and assembled rotors, is also summarized. Based on the above research, this paper uses the experimental and simulation methods to study the anti-fouling performance of the assembled rotors.First, the fouling experimental device of assembled rotors is designed and built, and the calcium carbonate is selected to simulate the growth of crystallization fouling in the tube. The influence of flow rate and flow bath temperature on anti-fouling performance of the assembled rotors is studied,and the anti-fouling performance of helical two-blade rotors with grooves and twisted tape is compared. The experimental results show that as the velocity increase, anti-fouling performance increased. What's more, as the temperature increase, anti-fouling performance decreased. But the influence of the flow bath temperature on the deposition of the enhanced tube with assembled rotors is smaller than that of the flow rate. Moreover, the asymptotic value of the dirt in the enhanced tube with helical two-blade rotors with grooves is 72% of twisted tape, which indicates that the helical two-blade rotors with grooves has a good prospect in the self-cleaning of the fouling.Secondly, the MgO particles are used as the circulating fluid to study the growth of the particles in the tube and the enhanced rotor with assembled rotors. In addition, the surface morphology of particulate fouling is observed by scanning electron microscopy (SEM), and performance of assembled rotors is analyzed from the microscopic point. The experimental results show that,compared with the tube, particulate fouling in enhanced tube with assembled rotors is less, sparser and more evenly distributed. It can say that assembled rotors have good anti-fouling performance, which, the anti-fouling performance of helical three-blade rotors better.Lastly, the numerical simulation method was used to study the anti-fouling performance of the assembled rotors with different spacing and different eccentricity distance. The variation curve of the volume fraction of particles in the axial length was obtained. The simulation results show that assembled rotors with no space have the best anti-fouling performance. For the eccentric position of assembled rotors, the increase of the eccentricity distance makes the particle fouling volume fraction decrease and when the eccentricity distance is 2mm, the best performance is inhibited.