Energy conservation certification for coal layer-combustion industrial boiler

The effect of boiler load on main operation parameters and the boiler efficiency were investigated, and the thermal efficiency distribution of nearly 300 coal-fired boilers was further analyzed. The results show that the exit gas temperature decreases as the boiler load decreases, while the unburned carbon contents in ash and slag, and CO content in flue gas usually increase. Correspondingly, the loss due to exit gas decreases, and the loss due to unburned solids usually increases. The loss due to surface radiation and convection increases. Taking into account changes of all the losses, the boiler efficiency decreases at lower loads. With reference to TSG G0002, Technical Specification for Energy Conservation Certification of Coal Layer-Combustion Industrial Boiler under off-Design Conditions has been drafted and the evaluating values of energy conservation for products have been proposed, including boiler efficiency under different test loads and CO concentration in flue gas. The target efficiency values vary according to the boiler capacity and fuel type. The CO concentration value is a limit that can be achieved by most boilers.