Coal is a main energy resource and many households in our country use honeycomb briquettes made of coal for heating and cooking. In summer honeycomb briquettes are mainly used as fuel for cooking. But they reveal some shortcomings such as difficulty in ignition and low combustion efficiency due to the need for high ignition temperature.
The most important thing is to reduce the time and energy needed for ignition of honeycomb briquette as much as possible, and to raise the combustion rate up to the level of gas combustion for instant cooking. 150 to 200 grams of wood sticks are needed for ignition of honeycomb briquettes. If the calorific value of wood is 16MJ/kg, as much energy as 2 400 to 3 200kJ is consumed for ignition alone. What is more, a large amount of flame and harmful gases are released due to the difference in the activation energy between coal and biomass, which pollutes the environment.
Therefore, many researchers have conducted studies to lower the ignition temperature and raise the combustion rate by lowering combustion activation energy of coal. To this end, they added combustion additive to coal or mixed coal and biomass. To prevent the release of much flame during ignition with wood sticks, some researchers have developed double-layer or multi-layer ignition honeycomb briquettes to be ignited with a sheet of paper or a match stick. The problem is that if biomass like raw sawdust is added to the upper sides of briquettes as it is, it produces smoke and exerts bad influence on coking power.
Jon Chol, a researcher at the Faculty of Mining Engineering, on the basis of the analysis of biomass ignition characteristics for its size, has studied the ignition and combustion characteristics of upper side ignition honeycomb briquettes and determined appropriate crushing size and blending rate of biomass.
The results showed that the upper side ignition honeycomb briquette added with biomass has ignition time of two to three minutes on average, combustion time of 75 minutes and combustion rate of 156.12g/min, and that the most appropriate biomass crushing size is 125㎛.
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