Parallel fixed bed reactor and fluid contacting apparatus and method

The present invention relates to an apparatus for evaluating catalytic performance of members of a catalytic library, comprising a reaction vessel assembly with a plurality of reaction vessels; a fluid handling system for providing fluid flow simultaneously through the plurality of vessels; and a detector for simultaneously analyzing vessel effluents of at least two of the plurality of vessels, the fluid handling system comprising an entrance control volume in fluid communication with the inlet of each of the plurality of vessels, a plurality of flow restrictors, and an exit control volume in fluid communication with the outlet of each of the plurality of vessels, each of the plurality of flow restrictors being other than a flow controller and being arranged upstream or downstream of one of the plurality of vessels, and wherein each of the plurality of flow restrictors provides fluid communication between one of the plurality of vessels and the entrance control volume or the exit control volume, and wherein maintaining a pressure in the entrance control volume higher than in the exit control volume results in fluid flow through the vessels, the flow restrictors being adapted such the resistance to fluid flow in each of the flow restrictors is approximately the same.