The utility model discloses a gas countercurrent liquid-
solid downer reactor and belongs to the technical field of chemical reactors. The reactor mainly comprises main structural units such as a liquid-
solid inlet, a gas separator, a
demister, a gas outlet, a gas baffle plate, a reactor main body, a gas inlet, a gas
distributor and a liquid-
solid outlet. In the reactor, gas moves upwards in the form of bubbles and is in countercurrent contact with a
liquid phase and a solid phase, so that the
interphase contact efficiency is improved, the
liquid phase and the solid phase move downwards along a gravity field, backmixing is small, downward drag force is applied to the bubbles, and the
gas retention time can be regulated and controlled by adjusting the
apparent velocity of the
liquid phase and the solid phase; the efficiency and the performance of the reactor are improved. The gas-liquid-solid three-phase reactor has the characteristics of simple structure, flexibility in operation, high
interphase contact efficiency, small backmixing degree, excellent reactor performance and the like, can be widely applied to a gas-liquid-solid three-
phase reaction process, and has a huge industrial application prospect.