Developing a mathematical model for the completekinetic cycle of direct synthesis of DME fromSyngas through the CFD technique

摘要

It is well known that the direct synthesis of Di-Methyl Ether (DME) from the Syngas ishighly exothermic; therefore, the temperature control for its production and hence asuitable heat transfer pattern is of ought most significance to the success of suchprocess. As such, slurry bubble column reactor is recognized to be a more suitablemeans for this purpose than other choices including fixed bed reactor which is the usualtype of system in which direct DME synthesis takes place. In other words, slurryreactors are desirable due to having suitable heat and mass transfer properties. In thisresearch a mathematical model for direct synthesis of DME from synthesis gas in aslurry reactor for a complete kinetic cycle including; CO consumption, Water-Gas shiftreaction and methanol dehydration steps has been developed and evaluated. This is donethrough FLUENT software incorporating k-ε model with 10% intensity (I.e.; usualindustrial value) and reactor hydrodynamic diameter of 8 cm. Then, investigation ofeffects of various parameters such as pressure (in the range of 25 to 40 bars),temperature (between 220-280 °C), inlet feed flow rate (of 200 ml/min) and inlet feedcomposition (of CO:HH2 = 1:1) on the performance of the reactor in terms of COconversion and selectivity toward production of the DME in this process wereundertaken. It is noteworthy, that the maximum error resulted from comparison ofresults obtained from current model and those of experimental data is less than 10% forconversion of CO selectivity toward DME which are reasonable consideringassumptions utilized.