Composite bed purification tower

The invention relates to a composite bed purification tower. The composite bed purification tower comprises a purification tower body and an ammonia spraying system, a desulfurization bed, an ammonia spraying mixing chamber and a denitration bed are arranged on the purification tower body from the air inlet side to the air outlet side in sequence; the desulfurization bed is communicated with flue gas to be treated, the ammonia spraying mixing chamber is communicated with the desulfurization bed, and the denitration bed is communicated with the ammonia spraying mixing chamber. According to the composite bed purification tower, the desulfurization bed and the denitration bed are arranged in the same tower body, the structure is compact, space is saved, and the overall cost of equipment is lowered; by means of a crossflow high-speed ammonia spraying mode in a narrow cavity of the ammonia spraying mixing chamber, gas injection kinetic energy is fully used to achieve forced convective mixing, the mass transferring