Elimination of flue gas by-pass is a gradually developing new tendency in flue gas desulphurization(FGD) area.The problems may occurin operation of wet FGD without by-pass are as follows:during cold-state start-up of boilers

the unburned oil stain and carbon particles etc in combustion-suppoting oil may result in pollution of the slurry from absorption tower of the FGD system

making it to cease being effective

and result in contamination and blockage of blades in the demister;the change of operation condition

such as sudden change of sulfer content in fuel coal

may affect the FGD system etc..For these

some general countermeasures have been put forward

i.e.before ignition and start-up of the boiler

especially before cold-state start-up

it is necessary to heat the ash hopper

insulating post sleeve

and insulated chamber of discharge electrodes for the electrostatic precipitator in advance of 24 h;ensure reliably putting the emergency sparying desuperheating devive at inlet of the desulphurization tower into service;at stage of injecting combustion-supporting oil to start the boiler up from cold-state

as well as injecting combustion-stabilizing oil under low load

the flushing frequency and flushing water quantity for the demister have to be increased;during abnormity of slurry from the absorpton tower

the slurry has to be replaced;controlling the quality of fuel coal

especially the ash content and sulfer content in the coal;strengthening chemical supervision for the FGD system

and enhancing the level of repair

maintenance

and management for the FGD system.