System for hydrogen production by dehydrogenation of formic acid (HCOOH), said system comprising: - a reactor vessel comprising a reactor space bound by a reactor wall, wherein said reactor vessel is arranged for holding a mixture of a catalyst and said formic acid in said reactor space, said reactor vessel further comprising a mixture inflow opening for allowing said mixture to enter, via said mixture inflow opening, said reactor space and a mixture outflow opening for allowing said mixture to exit, via said mixture outflow opening, said reactor space, and a gas outflow opening for allowing hydrogen originating from said mixture, via said gas outflow opening, to exit said reactor space; - an inflow conduit, communicatively coupled for fluid flow, via said mixture inflow opening, to said reactor space, wherein said inflow conduit is arranged such that said mixture, in use, is introduced in said reactor space, via said mixture inflow opening, in a predetermined direction having a tangential component arranged for stirring, in use, said mixture in said reactor space; - a pump, communicatively coupled for fluid flow, via said mixture inflow opening and said mixture outflow opening, to said reactor space, wherein said pump is arranged for withdrawing, via said mixture outlet opening, said mixture from said reactor space and introducing, via said inflow conduit, said mixture into said reactor space; - a temperature control arrangement, communicatively coupled for fluid flow to said pump, wherein said temperature control arrangement is arranged outside the reactor space for heating and/or cooling, in use, said mixture withdrawn from said reactor space to a predetermined temperature range before introducing, via said inflow conduit, said mixture into said reactor space. - a reactor vessel comprising a reactor space bound by a reactor wall, wherein said reactor vessel is arranged for holding a mixture of a catalyst and said formic acid in said reactor space, said reactor vessel further comprising a mixture inflow opening for allowing said mixture to enter, via said mixture inflow opening, said reactor space and a mixture outflow opening for allowing said mixture to exit, via said mixture outflow opening, said reactor space, and a gas outflow opening for allowing hydrogen originating from said mixture, via said gas outflow opening, to exit said reactor space; - an inflow conduit, communicatively coupled for fluid flow, via said mixture inflow opening, to said reactor space, wherein said inflow conduit is arranged such that said mixture, in use, is introduced in said reactor space, via said mixture inflow opening, in a predetermined direction having a tangential component arranged for stirring, in use, said mixture in said reactor space; - a pump, communicatively coupled for fluid flow, via said mixture inflow opening and said mixture outflow opening, to said reactor space, wherein said pump is arranged for withdrawing, via said mixture outlet opening, said mixture from said reactor space and introducing, via said inflow conduit, said mixture into said reactor space; - a temperature control arrangement, communicatively coupled for fluid flow to said pump, wherein said temperature control arrangement is arranged outside the reactor space for heating and/or cooling, in use, said mixture withdrawn from said reactor space to a predetermined temperature range before introducing, via said inflow conduit, said mixture into said reactor space.