Abstract: To solve the issue of cold startup under the condition of no external heat source in a single Unit 5 of a certain power plant, the micro oil heating air preheating system is designed and installed at the inlet air duct of Coal Mill A to obtain the hot dry air for the mill. The plasma ignition technology is applied for the boiler ignition and soot blowing with the compressed air is adopted in the air preheater at the beginning of the ignition. The steam produced by the boiler itself is used to satisfy the demands of air preheater blowing, feedwater deaeration, turbine shaft sealing and steam pump switching, to realize the boiler startup closure and the cold startup being achieved in a single unit. This method can save fuel oil and reduce energy consumption during startup with electrostatic precipitation launched at the beginning of the ignition, which is valuable for saving the construction investment and reducing the operating costs in thermal power plants.

Key words: 600 MW supercritical unit, heat source free, startup boiler free, cold startup