Tube bundle replacement for segmental and helical shell and tube heat exchangers: Experimental test and economic analysis

• Helix bundle achieved two to three times of operation run times than segmental bundle.
• Inspections show little fouling on the helix bundle in comparison with segmental bundle.
• The total cost for helix bundle is less than segmental bundle.
• The effectiveness of helix bundle is obviously higher than that with segmental bundle.

In this investigation, the second test analysis with more comprehensive evaluation with a focus on fouling mitigation, increased running-time and economic analysis are shown and then, the thermal design procedure for tube bundle replacement of critical heat exchanger of Butene-1 unit in Petrochemical Company as a case study are described. Finally, experimental data for the average heat transfer coefficient and pressure drop of shell-side in segmental and helix bundles are measured and calculated for the mass flow rate of 14.24 kg/s and then these data are compared with the data from code and EXPRESS. Moreover, additional comparison between code and EXPRESS results are provided to ensure the accuracy of calculation program in various mass flow rates. Based on the same shell in the case studies, the results showed that in addition to improved heat transfer performance of the helix bundle over segmental bundle, helix bundle achieved two to three times longer operational run times. From economic point of view, the results for replacement of segmental bundle with a helix bundle showed that initial and installation costs of helix bundle to segmental bundle could be increased, but maintenance and operating costs can be decreased in the helix bundle, 60% and 20%, respectively. Comparison between code and EXPRESS results with experimental data for the mass flow rate of 14.24 kg/s showed that the deviation in heat transfer coefficient and pressure drop are quite reliable for segmental and helix bundles.