US Patent 9737869 Reactor

A reactor includes a reaction-side flow passage through which a reaction fluid being a fluid constituting a reaction object flows; a temperature controller (heat-medium side flow passage) configured to heat or cool the reaction fluid from outside the reaction-side flow passage; and a catalyst configured to promote a reaction of the reaction fluid, the catalyst provided in the reaction-side flow passage so that a contact area with the reaction fluid is larger on a downstream side than on an upstream side in the reaction-side flow passage.