Device for recycling hydrogen in purge gas of synthetic ammonia refrigeration system

The utility model discloses a device for recycling hydrogen in purge gas of a synthetic ammonia refrigeration system, which comprises a hydrogen-nitrogen compressor, a cooling system, a first ammonia washing tower, a second ammonia washing tower, a methanol washing tower and a liquid nitrogen washing tower, the cooling system, the first ammonia washing tower, the methanol washing tower and the liquid nitrogen washing tower are communicated in sequence, and the hydrogen-nitrogen compressor is connected with the second ammonia washing tower through a pipeline. An inlet of the second ammonia washing tower is communicated to an ammonia cooler in the synthesis ammonia freezing system; and the cooling system is connected with an outlet of the synthesis ammonia conversion system. On the basis of the original system, the purge gas passing through the second ammonia washing tower can be compressed and boosted by the hydrogen-nitrogen compressor and then is introduced into the cooling system to be mixed and cooled with