Plate heat exchangers and microstructured reformers

Different flow arrangements exist for heat exchangers, namely, cross flow, countercurrent, and cocurrent flow. The main disadvantages of the cross-flow design are uneven temperature distributions, which also deteriorate the gas composition 

The channels of most plate heat exchanger/reactors are switched in parallel, which reduces the pressure drop compared to alternative flow patterns such as serpentine flow fields. However, flow equipartition is crucial for parallel flow arrangements. It is achieved by perforated plates [89] when a whole stack of plates is fed in parallel from the plate front. Such pinhole plates create additional pressure drop. In case the feed gas is distributed to each plate first and then by a dedicated inlet section to each channel of the plate, a sophisticated geometry of this inlet section [90] helps to achieve flow equipartition. An alternative is the variation of the channel width over the reactor length axis [91]. 

Catalysts from Siid Chemie were chosen for methanol steam reforming by Cremers et al. [100]. Because the catalyst activity was relatively low, a micro fixed-bed reactor was built with integrated heat exchanging capabilities. The reactor contained 60 micro fixed-bed passages, which took up 15.9 g of catalyst and 62 heating passages. The reactor was designed to produce 

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