TITLE: Reaction and heat transfer in a wall-cooled fixed bed reactor.

AUTHOR: S. H. Skaare.

INST.  AUTHOR: Norges Tekniske Hoegskole, Trondheim.

LANGUAGE: English

PUB.  TYPE: Thesis

PUB.  COUNTRY: Norway

SOURCE: Department of Energy [DEE],  Dec 93,  196p.  ISBN: 82-7119-571-9

NTIS ORDER NO.: DE95717546INW

ABSTRACT:

The problem of heat transfer in a catalyst filled wall-cooled reactor tube where a strongly exothermic reaction takes place has been studied.  The reaction was hydrogenation of carbon monoxide over a commercial cobalt supported on silica catalyst. A highly instrumented pilot reactor with measuring and analytical systems for recording of axial and radial temperature profiles and axial concentration profiles was constructed. Furthermore, mathematical models were developed for prediction of the reactor performance under steady state conditions, and an experimental investigation was carried out to obtain data for model discrimination and parameter estimation. The models were discretized into a set of algebraic equations by the method of orthogonal collocation. Experimentally determined temperature and concentration profiles were provided from measurements in the pilot reactor at steady state operating conditions.  Due to a very narrow limit of possible operating conditions the possibilities of variations of experimental parameters were rather restricted. This was due to instability problems commonly encountered in highly exothermic fixed bed operations. The experiments were performed at temperatures around 500 K, partial pressure of synthesis gas in the range 0.18-0.3 MPa and a H(sub 2):CO ratio of about 2.2 giving conversions in the range 25-50%. The reaction mixture was diluted with N(sub 2), keeping the total pressure constant at 1.0 MPa. Different reactor models including both heat and mass transfer were investigated. The models were adapted to give a best fit to the experimental data by estimation of parameters related to the thermal conductivity of the bed. The fit of the different models was evaluated by comparison of calculated and measured data for the optimal parameters. 113 refs., 29 figs., 6 tabs.

REPORT  NUMBER: NEI-NO-453