The invention discloses a method which applies in a PLC
control system to implement
calcium spraying and desulfurization inside a
circulating fluidized bed boiler, comprising the steps that outsourcing desulfurizer is transported and stored; a star unloader is used for feeding, a
solid flowmeter is used for measuring, and a helicoidal pump is used for transporting;
powder lot is blown into the boiler for
calcination and desulfurization by a lobe fan; a
flue gas SO2 sampling device is arranged on a
chimney, the concentration value of SO2 which is measured by a monitor is uploaded to the monitoring network of environment protecting department in a
wireless way by a
data collecting instrument, at the same time, the concentration value of SO2 is transmitted to the PLC
control system by the on-line monitor of the SO2; the
frequency conversion rotating speed of a motor of the unloader in controlled by the PLC, so that the desulfurizer can be automatically added; wherein, the instantaneous and integrated flow of the
solid flowmeter is transmitted to the monitoring network of environment protecting department by the PLC for being referred in real time. The method realizes the
automatic control of a desulfurization
system and on-line monitoring of the usage of limestone
powder in real time, at the same time, the desulfurization efficiency is improved, thus remarkably saving the usage of limestone
powder, reducing the running cost, and simultaneously lightening the labor intensity of operating staffs.