Recently, one of the new methods to enhance the heat transfer performance of the working fluids is dispersing metallic nanoparticles in a liquid. This solid-liquid mixture called nanofluid. Experiments have shown that nanofluids have substantial higher thermal conductivities compared to the base fluids [1]. One of the most important application of these nanofluids is heat exchangers. Increasing the heat transfer coefficient in these industrial systems reduces the heat transfer time and minimizes the size of the heat exchangers. In this study, application of alumina nanofluid in an industrial shell and tube heat exchanger has been investigated. One of the shell and tube heat exchangers of the Xylene petrochemical unit was selected for this goal. TEMA standard was used to design this exchanger. Al2O3 nano particles with the volume fraction of were applied. Exchanger design was performed at two stages: (i) using pure water as cooling water and (ii) using alumina-water as cooling water. The effective physical properties of the nanofluid such as density, thermal conductivity [2] and specific heat [3] were calculated from literatures. According our design procedure, petrochemical fluid was placed inside shell and cooling water was entered inside tubes. The heat transfer coefficient of nanofluid inside tubes versus Peclet number was estimated from literature [4]. Results show that using nanofluids as coolant increases the overall heat transfer coefficient of the exchanger from 45 to 50 Btu/ft2.R.h. Calculated results indicate that petrochemical fluid has the main effect on the overall heat transfer coefficient. So, there is no significant difference between overall heat transfer coefficient at these two cases. But this low change has an influential impact on the exchanger structure since it decreases the number of required tubes from 340 to 284 that reduces 9.3% of the required heat transfer surface. Moreover, it decreases the shell diameter from 29 inches to 27 inches. These changes in the exchanger size have an influential economic effect on the total cost. Our results show that using alumina nanofluids reduces the required tubes price of about 16% and also has a reduction of 6.9% of the shell cost. Finally, calculated results suggest that using nanofluids as cooling water in the shell and tube heat exchangers has a positive effect on the total cost reduction. However, the nanoparticles price should be defined in the overall cost.

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