Systems and methods for removal of mercury and/or hydrochloric acid from gas streams using calcium-containing particles

An industrial facility, comprising:

• a lime kiln configured to produce a lime kiln gas stream including lime kiln dust and mercury;
• a temperature adjustment zone downstream of the lime kiln and positioned to receive the gas stream,
• the temperature adjustment zone being configured to cool the gas stream;
• a temperature sensor positioned downstream of the temperature adjustment zone and configured to measure a temperature of the cooled gas stream;
• a controller in communication with the temperature sensor and the temperature adjustment zone,
• wherein the controller is configured to cause the temperature adjustment zone to cool the gas stream,
• based on the measured temperature, to about 250-350° F.;
• and
• an injection system configured to inject at least one of powder activated carbon or calcium-hydroxide.

A system for removing one or more air pollutants from a gas stream of an industrial facility, the system comprising:

• a cooling apparatus positioned to receive a gas stream including a first plurality of calcium-containing particles, wherein the cooling apparatus is configured to cool the gas stream;
• a temperature sensor positioned downstream of the cooling apparatus and configured to measure a temperature of the cooled gas stream;
• a controller in communication with the temperature sensor and the cooling apparatus, wherein the controller is configured to cause the cooling apparatus to cool the gas stream, based on the measured temperature, to about 250-350° F.;
• a pollutant sensor configured to measure at least one of mercury (Hg) or hydrochloric acid (HCl);
• and
• an injection system configured to inject a second plurality of calcium-containing particles, based at least in part on the measured Hg or HCl.