Patent ID: 7125007
Filing Date: 2006-10-24
Classification: B05B,Y10S

Abstract:
1. A control system for controlling the compressed air applied to one or more spray nozzles used in a flue gas cooling system wherein the one or more nozzles are of the type that operate to receive pressurized liquid and pressurized air and to provide an atomized liquid oriented at the flue gas to thereby cool the same, comprising: a liquid supply line coupled with the one or more spray nozzles including a flow meter disposed therein for sensing a flow rate of liquid supplied to the one or more spray nozzles; a compressed air supply line including an air flow valve disposed to adjust the amount of compressed air supplied to the one or more spray nozzles; and a spray controller coupled with the flow meter and the air flow valve, the controller operable in accordance with an algorithm based on flue gas flow and temperature characteristics at various operating conditions to provide a control signal to the air flow valve to adjust the amount of compressed air being supplied to the one or more nozzles as a function of sensed liquid flow rate; an adjustable liquid flow valve disposed in the liquid spray supply line disposed to receive a control signal from the controller to adjust the amount of liquid supplied to the one or more spray nozzles; and a temperature sensor located in proximate relation to the flue gases and disposed to provide a temperature sensing signal to the controller, wherein the spray controller having means for calculating, in response to receipt of the temperature sensing signal, a desired valve position for the liquid flow valve as,  with m being the desired valve position of the liquid flow valve, e being a difference between a measured temperature indicated by the temperature sensing signal and a set-point temperature, and Kp, Ki and Kd being proportional, integral and differential factors, respectively, and supplying a control signal to the liquid flow valve to adjust the liquid flow valve to the desired valve position to cause a change in a liquid flow rate through the liquid flow valve.