Purification method and device for tail gas of caprolactam device

The invention discloses a purification method and device for tail gas of a caprolactam device. The purification device comprises a tail gas induced-draft fan and is characterized in that a desulphurization device, a tail gas preheater, a gas-gas heat exchanger, a heater and a denitration reactor are sequentially arranged in a gas flowing direction, and the devices are communicated with one another through pipelines. The purification method provided by the invention adopts a combined technology of ammonia water absorption desulfurization and denitration based on an ammonia gas selective catalytic reduction method; the purification method adopts the purification device according to claim 1. Compared with the prior art, the purification method and device provided by the invention have the advantages of high safety and reliability, simple technology, low operating cost and the like.