Study On The Optimization Technology Of Large-capacity “W” Flame Supercritical Boiler

There are a variety of coal resources in our country, but the quality of coking coal is relatively scarce. Meanwhile, China is a country with coal as the main energy source, which the coal consumption in China’s total energy consumption accounts for about more than 70%. Such a pattern of energy consumption results that the energy structure of electric power industry in our country has a significant difference compared with developed countries. Up to now, the installed capacity of thermal power units in China has accounted for over 80% of the total installed capacity.In recent years, China’s rapid social economic development results in a substantial increase in energy demand, so the national energy policy requires that the thermal power plant uses less oil, more coal especially inferior coal. Due to the high carbonization degree and the low volatile matter of anthracite and lean coal, therefore the utility value in the chemical industry is not very high, but they can be used to generate electricity. In order to adapt to the needs of the development of power industry and solve the problem that the anthracite is difficult to burning, we began to introduce the “W” shape flame boiler from the 1980 s. Compared with the traditional boiler burning low volatile coal, this boiler has an unparalleled advantage in the aspects of combustion stability, burning performance, combustion efficiency and adaptability of coal. Large unit has the advantages of high efficiency, clean and green, less areas covering, etc…. However, the overall level of parameters is constrained by the metal material, manufacturing technology and technological level. The parameters of the mature thermal power units burning low volatile coal still remain in the subcritical level with the capacity of 600 MW. Under the general direction of the units’ parameters and capacities to ultra-high, the major power groups pay great attention on the 600 MW supercritical unit fueled with low volatile coal.However, from the current operation of the “W” shape flame boiler, the boiler of this type still exist the following problems: poor combustion stability, the pressure fluctuations are serious, there is no wind and the unit often runs in low oxygen conditions; slagging serious, which may lead to the shutdown and result in serious economic losses; generally high concentration of NOx emission which can cause serious environmental pollution; low economicality, low efficiency and serious heat loss.This paper is based on the actual, takes the Guodian Xingyang Coal&Electricity integration company’s 600 MW supercritical boiler as the research object and aims at the representative problems in the actual operation, such as NOx emissions with higher volume fraction, water wall temperature fluctuation in the process of load lifting, heat up faster, slagging serious and low economicality to conduct operation optimization adjustment and technical innovation. From the phenomena of the problem, we analysis the causes of the problem firstly. On the basis of clear reasons, we conduct the actual optimization; the optimization process includes two parts, operation and combustion adjustment and equipment modification. As we can see from the results of the adjustment, the operation of the boiler has been improved markedly and we have achieved great returns. This article has great guiding significance for other production units.