The challenging of this work is to present a thorough study of implementing heat transfer intensification in heat exchanger network (HEN) retrofitting, including all details of exchanger geometry, stream bypassing and splitting, temperature-variation of properties, LMTD and its correction, and pressure drops. This leads to very complex mixed integer nonlinear programming (MINLP) problems rarely reported before. By adopting the MILP-based iterative approach proposed in the earlier work (Pan et al., Chem Eng Sci. 2013;104:498-524.), temperature-variation of properties, LMTD and its correction are initialized to parameters at first, and the rest nonlinear terms are then linearized and expressed as first-order Taylor series expansions. Finally, two iteration loops are executed to find optimal solutions. A small-scale motivating problem and an industrial scale problem are presented to demonstrate the validity and efficiency of the proposed methods. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 2052-2077, 2018