A hydroformylation system for making aldehyde by reacting olefin with synthesis gas by way of hydroformylation is improved by multi-stage condensation of gaseous reactor effluent for providing liquid feed to a gas-liquid contact zone. the tower is in the interval 0\xb0 to 40\xb0, most preferred around 30\xb0. In one detailed embodiment, the airfoil trip strips in the passages having constant height and constant pitch over each leg in most legs of the passages except for the legs closest to the edge regions of the airfoil. When the connection of the external power supply for charging the rechargeable battery to the apparatus is not detected, the power supply does not supply electrical power to the electronic device even during operation of the apparatus. The self-expanding stent extends across the tubular conduit into the ascending aorta.