Study On Monitoring Of Coal-BFG-COG Blended Combustion And Control In Power Plant Boiler

Co-firing of coal with BFG (Blast Furnace Gas) and COG (Cove Oven Gas) is an important study in the boiler combustion field. With the development of national economy, co-firing of coal and gas study is becoming increasingly important. The objective of co-firing study should solve not only the safety and economy in the co-combustion of pulverized coal and gas, but also the problem of environmental emissions.Through an in-depth analysis of combustion characteristics of multi-fuel fired 670t/h boiler in a power plant, we established a combustion program of burning coal and gas mixture, identified the largest proportion of gas, and built a flame image detecting system used for testing coal/gas mixed combustion.By monitoring the real-time combustion conditions through the flame image detectors arranged in certain furnace position, we can extract the common combustion characteristic parameters, set a reasonable threshold, achieve the diagnosis of combustion stability of the multi-fuel fired boiler and early warning function. The data of three-dimensional temperature field displayed that at different ratios of blended gas, the furnace temperature characteristics will take on different changes. With increasing gas proportion, furnace flame core temperature drops, and flame center moves up. When combining these kinds of early warning signals with burning radiation, temperature level and the furnace flame ON/OFF signals, we can also make an effective integration of the boiler fire warning signals and FSSS systems, and ultimately develop a new method of combustion warning. Visualization system can reflect changes in operating conditions and power loads, create the corresponding relations between furnace average/maximum temperature and load, and then be utilized to optimize the unit's part of the circuit using the radiation signal.Leading radiation energy as a feed-forward signal into the opium volume of the main steam temperature control loop can improve the quality of the temperature as well as the stability of steam parameters while blending with gas combustion. Experimental analysis indicates that at different air/fuel ratios, the radiation signal has a favorable corresponding relation with the actual generation power. Reasonable regulating the proportion of coal, the amount of BFG and COG through the previously mentioned corresponding relationship between them, and through the monitoring and analysis of the combustion and unit parameters lead to form a multi-fuel on-line combustion adjustment system and thus obtain better furnace combustion efficiency and low NOx emissions.