Plate and Channel Microreactors

A straightforward manner to apply microtechniques to electrochemical synthesis reactors is to develop parallel plate reactors with a sub-millimeter inter electrode gap. 

The plane electrodes are separated by isolating spacers, which may lead to the formation of parallel flow channels. In any case, the electrodes are plane sheets which can be replaced and thus made out of any plain material, e.g. nickel, lead, glassy carbon or graphite. Recent technolo cal developments made at the Institute of Microtechniques, Mainz [6, 7], have led to the construction of versatile microchannel electrochemical reactors. Indeed, the pressure can be elevated to up to 35 bar and the electrodes can be stacked in order to increase the overall electrode area. Moreover, polymer electrolyte membranes can be inserted, separating anodic and cathodic compartments if necessary, and finally heat exchangers may be integrated. 

A major interest of micro-scale plate and channel reactors is related to the high specific electrode area, permitting operation in a single-pass high onversion mode. This mode is characterized by some special features which are detailed in Sections 17.3.3.1-17.3.3.4. The subsequent sections discuss the experimental and theoretical investigations reported in the recent literature. 

---

Due to the important ratio between the reactor length and the inter-electrode distance, plate and channel microreactors behave like plug flow reactors. The maximum possible conversion is reached if the reaction is under mass transport control on the entire electrode surface. The combination of the local diffusion-limited... 

---