Butadiene tail gas hydrogenation unit and hydrogenation method

The invention discloses a butadiene tail gas hydrogenation unit and hydrogenation method. The unit comprises a hydrogenation reactor and a product tank, wherein a diluting tank, a compressor, a condenser and a gas-liquid separating tank are arranged in front of the hydrogenation reactor; the diluting tank is sequentially connected with the compressor, condenser and gas-liquid separating tank, and then connected with the inlet of the hydrogenation reactor; the hydrogenation reactor is connected with the product tank; an outlet pipeline of the product tank is connected with the inlet of the hydrogenation reactor; and a heat exchanger is arranged between the product tank and the diluting tank. The hydrogenation method comprises the following steps: butadiene tail gas is diluted, compressed, condensed, and subjected to hydrogenation reaction. The unit and method disclosed by the invention can solve the problem that the butadiene tail gas can not be easily liquefied; and the unit has the advantages of high operation safety, energy saving and low C4 loss.