Search

Heat exchanger network synthesis (HENS) is an effective tool for heat recovery in chemical and petrochemical industries. This study aims to show a method for HENS with the consideration of different shell-side flow arrangements in shell-and-tube heat exchangers. The proposed MINLP model is modified from the stage-wise superstructure model, incorporating newly developed correlations for shell-side pressure drop calculation for the helical baffle. The objective is to minimise the total annual cost (TAC) with a trade-off between the cost of different shell-side heat exchangers, utility cost, and pumping cost. The selection of baffle design is decided by the saved pumping cost and the increased area cost. The proposed model is tested from different points of view: with/without utility constraints and different statuses of the streams. Three case studies are presented and compared with the results from the literature. The proposed method with different shell-side baffles can reduce the heat transfer area and pressure drop. For fixed utility consumptions, the TAC in a case study is decreased by 8.9% with mixed baffle types. Although the unit per area cost of the helical baffle is higher than the segmental baffle, the increased investment cost could be compensated by the reduced operation cost, especially for plants with high viscosity streams and long-term cost-saving. [ABSTRACT FROM AUTHOR]

In the present work, the effect of the baffle pattern on the heat transfer and fluid flow characteristics of shell-and-tube heat exchangers are experimentally investigated, including tri-flower baffle, pore plate baffle, rod baffle, segmental & pore baffle and segmental baffle. In order to compare the hydrodynamics and heat transfer characteristics of the five heat exchangers, a water-water heat transfer experiment system is built. Based on the experimental data, and at the same flow rate, comparison with segmental baffle, the h s of tri-flower baffle and pore plate baffle augment 33.8% and 17.7%. The pressure drop of the rod baffle, tri-flower baffle and segmental & pore baffle decrease are 70.1%, 19.5% and 31.1% lower than that of the segmental baffle. The comprehensive performances h s /Δ p of the rod baffle, tri-flower baffle and pore plate baffle are all superior to that of the segmental baffle. Finally, the experimental correlative formula is raised for the four heat exchangers, and an optimal design scheme for shell side heat transfer enhancement is proposed. • Four types of baffle pattern of heat exchangers are experimentally compared. • Pressure drop and heat transfer performance are experimentally investigated. • Experimental correlative formula is fitted for the four heat exchangers. • An optimal design scheme for shell side heat transfer enhancement is proposed. [ABSTRACT FROM AUTHOR]

In this study, diverse baffled longitudinal flow shell-and-tube heat exchangers (STHX) are contrasted with segmental baffle shell-and-tube heat exchanger (SG-STHX). Experimental data are obtained with municipal water served as the working fluid, and the shell-side volume flow rate ranges from 1.79 m3/h to 7.42 m3/h. The components of the shell-side pressure drop are discussed stand on different flow patterns. The maximum proportion of pressure drop in tube bundle section of rod baffle shell-and-tube heat exchanger (RB-STHX) is 12%, while it has nearly taken up 70% shell-side pressure drop for both SG-STHX and large-and-small hole baffle shell-and-tube heat exchanger (LSHB-STHX). The energy efficiency of three tested STHXs is deliberated from three perspectives, including entropy generation, exergy destruction, and efficiency evaluation criterion. The longitudinal flow pattern performed superior energy efficiency, particularly for RB-STHX with the least irreversible energy loss and the most available work. Grounded on the energy-saving potential of RB-STHX, further numerical simulations on the shell-side thermo-hydraulic performance of RB-STHX are conducted. The nexus between geometrical parameters of RB-STHX and its thermal-hydraulic performance are studied. The thermal-hydraulic performance and energy efficiency discussed in this study support further design and application of longitudinal flow STHX to retain inherent superiorities with advanced performance. • Only 12% of the total pressure drop in the shell-side of RB-STHX is derived from the tube bundle section. • RB-STHX performs 173%∼223% higher EEC than LSHB-STHX with the least irreversible energy loss. • Rod baffle shell-and-tube heat exchanger shows the best comprehensive performance. • Numerical investigation of the heat transfer enhancement. • Factors: tube arrangement, rod shape, baffle arrangement, and baffle number. [ABSTRACT FROM AUTHOR]