Tube bundle replacement for segmental and helical shell and tube heat exchangers: Performance comparison and fouling investigation on the shell side

摘要

Conventional segmental baffles in shell and tube heat exchangers, while having an excellent record of acceptance and functionality, represent some limitations and shortcomings. In particular, shell-side flow path is wasteful which causes excessive pressure loss while recovering less heat transfer. This particular arrangement of baffles also limits maximum thermal effectiveness and encourages dead zones where fouling occurs. This paper describes the results of tube bundle replacement of a segmental shell and tube heat exchanger with a helical heat exchanger, which was conducted in Tabriz Petroleum Company. The aim of the project was to reduce fouling and pressure drop of the critical heat exchanger and; as a result, reduce operation and maintenance costs. Present paper consists of 3 phases. First, tube bundle replacement in industrial field and also the advantages of helical baffles over conventional segmental baffles are going to be discussed. Then, due to limits on the access to the heat exchangers in production lines, comparison of shell-side flow behavior in both cases is going to be presented by CFD means. Finally, computational code is going to be introduced to investigate on heat transfer and pressure drop for both segmental and helical shell and tube heat exchangers.