Study On Fouling Monitoring And Sootblowing Optimization For Coal-Fired Boilers

Coal-fired boilers of power stations mostly take coal as their fuel, which produce ash and slag during the operation, inevitably leading to fouling problems on the interior surfaces. Fouling can has an adverse effect on the heat transfer efficiency between gas and water. Sootblowing is an effective method to clean fouling and enhance boiler heating surfaces performance, which consumes high pressure and high temperature steam. A common practice for sootblowing scheduling is the operation personnel utilizing fixed time sequences for the sootblowing equipments, and the timing sequence is established based on plant measurements and experiences, which is usually incomplete and leads to over-cleaning and waste of sootblowing steam.This thesis lucubrates the research of fouling monitoring and sootblowing optimization for coal-fired boilers. Firstly, according to the study of 300MW coal-fired boiler, the library of corresponding physical parameters and structural parameters is set up and some of the major calculations of the thermal system are described. As for the radiation heating surface of the furnace, take the effective coefficient of the thermal water wall as the fouling characteristic parameter, and then establish the overall monitoring model of a slagging heating surface based on the lumped parameter model and furnace exit gas temperature. Then , Cleanliness Factor is the fouling characteristic parameter of convection heating surface. This monitoring model is based on energy conservation and mass conservation principles, and taking the variable condition into account. Lastly, a method of determining the best blowing cycle is proposed based on the principle of minimum operating cost. The heat loss caused by fouling and sootblowing cost are both converted into heat units so as for the calculation of optimization.Through the research methods of this thesis and the corresponding calculations using off-line data collected by DCS, a result can be concluded that the fouling monitoring and sootblowing optimization can be achieved to some extent.