Dry scrubbing systems are used to control acid gas emissions primarily from combustion sources such as utility and industrial boilers, municipal and medical waste incinerators or industrial processes such as glass furnaces.

Dry scrubbing systems only remove acid gases and therefore must be followed by a particulate control device (ESP or fabric filter) prior to exhausting the gases to the atmosphere.

Dry sorbent injection involves the addition of a dry alkaline material (usually hydrated lime or sodium bicarbonate) into the gas stream to react with any acid gases that are present. The sorbent can be injected directly into the flue gas duct ahead of the particulate control device or into an open reaction chamber. The acid gases are adsorbed onto and react with alkaline sorbents to form solid salts which are removed in the particulate control device.