Improving heat transfer to recovery boiler superheaters using optimization and computational fluid dynamics

Viljami Maakala, Mika Järvinen, Ville Vuorinen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    The flow field in the superheater region of a recovery boiler has a great effect on the heat transfer to the superheaters. By optimizing the How field, it is possible to utilize the heat transfer surfaces better and improve the total heat transfer to the superheaters. When the heat transfer performance is optimized, the area of the superheaters can be minimized, which leads to substantial cost reductions. The objective of this work is to find a superheater region design that maximizes the heal transfer to the superheaters in a typical modern 7000 tds/d recovery boiler. The optimization procedure is carried out by using a developed program which combines a simulated annealing (SA) optimization method, a polynomial regression surrogate model, and a superheater region computational fluid dynamics (CFD) model in a novel way. The present study is the first work that uses optimization coupled with CFD to investigate the superheater region of a recovery boiler. The optimization program found a large number of designs that improve the heat transfer to the superheaters, compared to the initial design. We chose two designs, A and B, among the best designs found and propose them as alternatives for an improved superheater region design. The design A, which is the best design found during the optimization, is characterized by a large furnace nose, and it improves the heat transfer to the superheaters by 5%. The design B, which conversely has a small furnace nose, improves the heat transfer by 3%. The results of this work can be used to redesign the superheater region with less superheating surface than in the original design. This will lead to major cost reductions, considering the large size of the boiler and the expensive materials required in the superheaters.

    Original languageEnglish
    Title of host publicationPEERS Conference 2015
    PublisherTAPPI Press
    Pages717-730
    Number of pages14
    Volume2
    ISBN (Electronic)9781510817586
    Publication statusPublished - 2015
    MoE publication typeA4 Conference publication
    EventTAPPI PEERS Conference - Atlanta, United States
    Duration: 25 Oct 201628 Oct 2016

    Conference

    ConferenceTAPPI PEERS Conference
    Country/TerritoryUnited States
    CityAtlanta
    Period25/10/201628/10/2016

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