The Cold Simulated Experimental Study On 220t/h Pulverized Coal Boiler Using Reburning Rechnology

The cold model tests were completed on the mixing characteristicsbetween the reburning airflow and main airflow or between OFA and mainairflow in a cold model test-bed according to the practice situation of 6#boiler in Jianyou power plant in Sichuan Provice and the requirements ofindustrial tests for low NOx reburning test project from State Electric PowerCompany. The cold simulated experimental study included: 1. Different disposal style for the reburning air & burning out air(tangential or front and rear walls) and their disposal heights. 2. Different momentums of OFA ( under the condition of constant airflowof primary area and condition of constant flux inputted simulated boiler). 3. The mixture of main airflow and different combination betweenreburning airflow and OFA. In order to measure the mixing characteristic, different temperaturespout test method was used. The room air was used as main airflow and OFA.In the same time, heated air was served as reburning natural gas. A few layersof temperature measuring nets was fixed in the furnace in the test-bed. Thedistribution of the concentration of diffenent temperature air was gottenthrough measuring the distribution of the temperature in the furnace. Finally,the mixture situation in reburning area and burnout area were gotten totally.Some industrial data acquisition models were used to build a computer dataacquisition and treatment system to complete the temperature measuring intemperature measuring net in the cross level in the furnace. A graphicaltreatment software was used to treat temperature data and realize the visibleresults. Through analysing the distrabution of the temperature-rising, it wasfound that some mixing characteristic could to used to offer consults tocommercial-scale test. From the experiments and analysis, below results were gotten: (1) It was benefited to reduce the emisses of NOx that the tangentialreburning system was used, which was as the same as the test results before inour Lab. (2) 0FA jetting into model furnace from front and rear walls could reducethe power of whirl in above part of the furnace. And this distribution couldalso decrease the difference of the heat distribution and heat transfer in thefurnace. On the other hand, it was not very good for the mixture of the gasesand decrease of the heat transfer in the furnace if OFA was jetting into thefurnace tangentially. (3)Considered the effects of the arrangement heights of the jets, it wasbenefit to rebunning and borning out that reburning airflow was spoutedtangentially and OFA was spouted at middle height level from the front andrear walls. (4)It needed to consider the practice boiler's detail to have reburningairflow spouted tangentially and 0FA spouted into furnace at lower or upperlevels from the front and rear walls.