Heat Exchange Reformers are a recent commercial technology that are a scaling down of tubular steam reformers used for hydrogen production in refineries. A common design element of Heat Exchange Reformers is the bayonet tube. The tube is closed at one end and has an interior wall that divides it into a central tube and an annulus. Typically, the feed enters the central tube and exits via the annulus. Usually a catalyst, in the form of a conventional pellet, is placed in the tubes of the reformer and a hot gas (i.e. from a combustor) or other process effluent circulated external to the bayonet to provide the heat of reaction.

Heat Exchange Reformers have been able to achieve a high thermal efficiency and are compact unit both in volume and mass.

In a preceding investigation, a bayonet tube for methanol reforming was designed for an approximately 4 kWe auxiliary power unit based upon conventional performance metrics and operation at steady state.

This intent of this investigation is to compute the transient characteristics of the above reformer for a large step increase in the feed flowrate from low or standby power to full power. An important metric is the time required for the reformer to re-establish steady state and attain full continuous power. Using this metric (and others), the suitability of the design will be reassessed.

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