Patent ID: 8182583

Claim:
A method for managing powdered activated carbon (PAC) injections for controlling mercury emissions from coal-fired boilers, comprising the steps of: storing (i) an operator selectable setpoint for a mercury concentration in flue gases, and (ii) a timer setpoint for checking the mercury concentration in flue gases exiting through a gas exhaust stack in a plant control system database; storing a mercury concentration value received from a mercury continuous emissions monitor in the plant control system database; storing a PAC injection rate from an activated carbon injection system in the plant control system database; determining if the processing logic for managing PAC injections is running on a plant control system; reading the mercury concentration setpoint, the mercury concentration value, the timer setpoint, and a rate of PAC injection from the plant control database; comparing the mercury concentration value to the mercury setpoint by the plant control system; comparing the PAC injection rate to a PAC injection threshold value; sending a signal from the plant control system to the activated carbon injection system to increase PAC injection by a predetermined amount if the mercury concentration value is greater than the mercury setpoint, and if the PAC injection rate exceeds the PAC injection threshold value; and sending a signal from the plant control system to the activated carbon injection system to decrease PAC injection by a predetermined amount if the mercury concentration is less than the mercury setpoint, and if the PAC injection rate exceeds the PAC injection threshold value.