The Influence of Straw Shape on the Formation of Deposits during Straw Briquette Combustion

During the combustion of straw, the formation of deposition, which destines to furnace erosion and exerts great influence on safety operation, on heating surface is affected by many factors. This paper studies influences of straw shape on the formation of deposits. Results are as follows: The shape change of fuel affects the process of fuel combustion, accordingly, it affects the formation law and properties of deposits: first, The change rule of deposition rate is different from the combustion of native straw, second, the deposition rate and amount are significantly lower than that produced by the native straw, at last, the shape of fuel has an important influence on the characteristics and composition of deposits: in fifteen minutes, the deposits are made up of black carbon, gray-black, feel smooth and are scattered, after an hour, the deposits are silver-gray, feel rough and are bonded together to form massive particles, whose surface was glassy and sintering phenomenon. The amount of alkali metal escaping from fuel increases with the furnace temperature rising, in addition, the shape of fuel is also conducive to form low melting point eutectic of alkali metal and SiO2.