Method for preparing high-purity sodium formate by using tail gas of synthesis ammonia liquid nitrogen wash device

The invention provides a method for preparing high-purity sodium formate by using tail gas of a synthesis ammonia liquid nitrogen wash device. The method comprises the following steps that: the tail gas generated by the synthesis ammonia liquid nitrogen wash device is compressed to a proper pressure by a compressor, the compressed tail gas is mixed with sodium hydroxide liquid conveyed by using a liquid alkaline pump, and the mixture is preheated and then enters a synthesis reactor to react to generate qualified diluted sodium formate; and the generated diluted sodium formate solution is concentrated in an evaporating manner, centrifugally separated and dried with air to obtain the high-purity sodium formate with the purity being above 99 percent. The method provided by the invention solves the problem that the tail gas of the synthesis ammonia liquid nitrogen wash device is used as a combustion gas, is low in recycling value and pollutes the environment, and solves the defects of lagging production equipment