Dry water absorption balance control process method with low-temperature heat recovery

The invention relates to a dry water absorption balance control process method with a low-temperature heat recovery function. The dry water absorption balance control process method comprises a drying unit, a low-temperature waste heat recovery unit, a secondary absorption circulating acid concentration adjusting module, a desorption tower, a dry acid buffer tank and an underground tank which are arranged in sequence. The method has the beneficial effects that low-concentration sulfur dioxide conversion is realized, 98% acid-water balance cannot be maintained in the dry absorption process when a smelting flue gas acid making system containing converter blowing is started and stopped, and the extraction amount of dry acid is changed due to the fact that the converter is periodically operated, the flue gas amount and the sulfur dioxide concentration greatly fluctuate in the acid making process of the smelting flue gas containing converter blowing; the acidity of the HRS is relatively low in a short time, and eq