Apparatus and method for evaporating waste water and reducing acid gas emissions

A method for evaporating waste water and reducing acid gas emissions, comprising:

• adding an alkaline reagent to a waste water to produce alkaline waste water;
• transporting a first portion of a flue gas emitted by a combustion unit to an evaporator device such that the first portion of the flue gas bypasses a pre-heater and is contacted by the alkaline waste water to evaporate the alkaline waste water, to reduce acid gas emissions, to produce a cooled and humidified first portion of the flue gas, and to produce dry solid particulates;
• separating the dry solid particulates using a particulate collector to obtain separated dry particulates;
• transporting a second portion of the flue gas emitted by the combustion unit to the pre-heater to heat a fluid in the preheater to produce a heated fluid supplied to the combustion unit;
• and
• merging the cooled and humidified first portion of the flue gas with the second portion of the flue gas, after the second portion of the flue gas has passed through the pre-heater, to produce a merged flue gas.