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Heat integrated distillation : the impact of heat transfer on Murphree tray efficiency

The design of a heat transfer sieve tray and its operation in an adiabatic 150 mm diameter distillation column is described. The capability to transfer a significant amount of heat is pivotal; hence, altering the vapour and liquid composition in a traceable way. The design philosophy of the heat transfer sieve tray and appropriate sampling devices are explained in detail. A review of heat integration technology is included. Numerous experiments with a binary mixture of methanol-water have been conducted in the cooling and heating mode respectively. The influence on Murphree tray efficiency of key variables like vapour flow rate, reflux ratio and heat flux were investigated. Simultaneously, overall heat transfer coefficients and plate-to-forth heat transfer coefficients were measured. Prediction methods for Murphree tray efficiency and stage models are reviewed. Based on the review, a model for stimulating a diabatic tray is proposed. The model is a modified nonequilibrium model including material and energy balances, rate equations and equilibrium relations. A set of equations for modelling a binary mixture is presented. Prediction methods for the overall and plate-to-forth heat transfer coefficients are presented. The prediction methods utilised heat flux, plate temperature, heat transfer medium temperature and froth temperature profile data. The experimental heat transfer coefficients were correlated with the plate-to-froth temperature difference in the heating mode, in which nucleate boiling is promoted and with the vapour velocity in the cooling mode, where convective cooling/condensation takes place along the vapour path. The experimentally obtained heat transfer coefficients and heat transfer correlations might be useful as contributor of real data in the modelling of diabatic distillation trays.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:653177
Date January 2004
CreatorsKaeser, Michael
PublisherUniversity of Edinburgh
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://hdl.handle.net/1842/12324

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