Evaluation of Laminated Porous Metal sintered felt as catalyst support

A laminated porous metal fiber sintered felt acting as a catalyst support was used in a cylindrical methanol steam reforming microreactor for hydrogen generation.

Microreactor is widely used in diverse chemical reactions for its small size, high specific surface area and outstanding heat and mass transfer properties. Liquid hydrocarbon as fuel can be instantly transformed into hydrogen-rich gas in suitable catalytic reaction conditions. This post gives a feasible idea to solve the hydrogen source problem for fuel cell. The microreactor with porous materials used as catalyst support is featured by a reaction flow path and low pressure drop. The catalyst supports have three dimensional porous structure and large specific surface area, so the catalyst can be easily coated on the porous material to develop a stable catalyst structure.

Metal foams are developed by direct forming of metals comprising of three dimensional pore structure, high specific surface area and low density. Although the fabrication of metal foam requires the specialized equipment with high production cost. It prevents the widespread application of metal foams. The foams made from copper, Nickel and FeCrAl materials are widely used in different types of catalytic reaction processes.

Porous copper sintered fiber felt had a relatively uniform three dimensional interconnect structure, that was advantageous to the homogenous loading of the catalyst. Additionally it is very easy to find out that copper/zinc/aluminium/zirconium catalyst could be effectively loaded on the sintered fiber felt with 80% porosity by using two layer impregation method.

Catalyst support by sinteredfiber felt  with uniform porosity structure offered good performance. When the reaction temperature was up to 300oC, the methanol conversion was reduced, and hydrogen gas flow rate increased. The sintered fiber felt with 80% porosity showed a much better reaction performance of microreactor.

A performance comparison of fiber felt with uniform porosity structure and gradient porosity structure serving as catalyst support operated at different reaction temperatures. When the reactant was into sintered fiber felt with gradient porosity changing from 90% to 70%, the maximum methanol conversion and hydrogen gas flow rate was discovered at different reaction temperatures. When the reaction was performed at temperature up to 380oC, the methanol conversion and hydrogen gas flow rate could be above 98%. This result can be attributed to the gradient porosity structure that could increase the capillary diffusion to enhance the heat and mass transfer of gas reactants in the sintered fiber felt. Additionally the reactant diffusion rate could match with the reactant chemical rate in the sintered fiber felt featuring a gradient pore structure because of optimal catalyst distribution.

It can be easily concluded that a higher reaction performance can be received when the reactant is fed from high porosity to low porosity part for the sintered felt with a gradient porosity structure.

To increase the hydrogen production, the laminated sintered mesh fiber felt as the catalyst support was used in the cylindrical methanol steam reforming microreactor for hydrogen development. It is found that sintered fiber felt attained better reaction performance .