Batch reactors for scalable hydrogen production.

摘要

A novel batch reactor concept is proposed for the catalytic production of hydrogen in distributed and portable applications. In the proposed CHAMP (CO2/H2 Active Membrane Piston) reactor, a batch of hydrocarbon or synthetic fuel is held in the reaction chamber where it reacts, or breaks apart, producing hydrogen. Simultaneously, the hydrogen is separated from the mixture by permeation through an integrated selective membrane. These processes proceed to the desired level of completion at which point the reaction chamber is exhausted and a fresh batch of fuel mixture brought in. Unique to the CHAMP reactor is the ability to precisely control the residence time, as well as the ability to compress the reaction chamber dynamically, or mid-cycle, in order to increase the instantaneous hydrogen yield rate.;Reactor models were developed in order to study the performance characteristics and optimize the design and operation of the CHAMP reactor. First, the ideal limits of performance (in the absence of transport limitations) were contrasted with those for continuous flow designs. Then, a coupled transport-kinetics model is employed to quantify the effects of mass transport limitations on reactor performance and search the design parameter space for optimal points. Two modes of operation are studied: fixed-volume mode wherein the piston is stationary and constant-pressure mode in which the rate of compression matches the permeation of hydrogen through the membrane. Finally, to validate these numerical models and confirm the understanding of the key operating principles, test reactors were built and experimentally characterized.