2013 2(13)

RESEARCH OF BURNING LOW QUALITY COAL

Yakimova I.S., Fursov I.D., Zhukov E.B.

I.I.Polzunov Altai State Technical University, Barnaul, Russia

Higher prices for oil and natural gas, as well as significantly lower their reserves, compared with reserves of fossil fuel, makes less attractive the use of gaseous and liquid fuels for steam and hydronic boilers of low and medium power.

Existing technologies for burning low-grade fuel have a number of fault that prevent full use of fuel's energy. The use of alternative fuel in power industry is also difficult because of insufficient knowledge of the properties of these fuels and combustion processes in a furnace.

Purpose is to involve lignite of Munayskiy coal mining in the fuel balance of the Altai Region and development of boilers contributing to efficiently burn this coal to increase efficiency of the boiler.

At the initial stage of the development of new furnace for boilers firing low-quality fuel numerical methods are widely uses to determine the geometry and arrangement of secondary/overfire air nozzles and air distribution to nozzles.

The next step is the experimental verification of the calculated data on scale facility or development of the project and construction of the boiler. In both cases, the experimental data are analyzed for error correction.

The results of combustion of single fuel particles experiments are shown in article. The experiments have carried out with particles of different masses lignite Munayskiy coal mining on the facility to determine the dynamics of the thermal decomposition of the fuel. The formula for calculating the time of the fuel combustion stages have proposed. The calculated and experimental data have been used for the numerical simulation of furnace’s aerodynamics in the calculation of the required residence time of the particles in a furnace to complete combustion. The proposed formula may use in the calculation of similar schemes of low-grade fuel firing.

Values refined the following factors on burning lignite of Munayskiy coal mining at vortex combustion chamber are the coefficient of thermal efficiency of furnace plate, coefficient considering the position of the flame maximum temperature, the heat loss from the chemical and mechanical incomplete combustion of fuel.

On the basis of analyzing the characteristics of lignite of Munayskiy coal mining prescriptions provided to further construction of furnace for efficient coal firing.

Profile of furnace have been proposed. Such profile allows keeping the fuel particles in the combustion chamber until they are burning out.

The results of the work have been used in the development of a series of hydronic boilers heat capacity of 1...3.5 MW. Boilers of this series operated in Russia (the Altai Region, the Kemerovo Region, the Novosibirsk Region, the Omsk region) and Belarus. In addition, these data have been used in the reconstruction of steam boilers with capacity of 10 t/h and hydronic boilers with capacity of 10 MW.

Results of numerical modeling are in accordance with the experimental tests. This is indicated the ability of mathematical modeling in the early stages of the new furnace development instead of experiments that reduce the cost and accelerate their entry into operation.

© SPIC "Kappa", LLC 2009-2013