燃煤/秸秆成型燃料层燃混烧试验研究

以一台额定热负荷为7 MW的燃煤链条锅炉为试验对象,系统研究了燃煤/秸秆成型燃料层燃混烧过程。热重热流分析结果显示,燃煤/秸秆成型燃料层燃混烧可显著降低灰渣和飞灰的含碳量,从而使固体不完全燃烧热损失降低、锅炉热效率提高。炉排上混合燃料的特殊分布形式一方面改善了燃煤的着火特性,另一方面降低了通风阻力、提高了氧气在燃料层内的渗透能力;同时,有效抑制了受热面结渣和尾部烟道飞灰沉积现象。掺混比例对炉膛温度以及CO、NOx和SO2的生成量具有一定的影响,随着掺混比例的增大,炉膛温度、NOx和SO2生成量均有所降低,但CO排放有所提高。在组织燃煤/秸秆成型燃料层燃混烧时,应控制燃料层厚度在115~120mm左右,炉排转速在550r/min以下,掺混比例以23%~25%为宜,并应强化挥发分燃烧区域的气流扰动。研究成果为农业废弃物能源化利用开辟了一条新途径。

Experimental Investigations on the Layer Co-combustion of Coal/Biomass Briquette Blends

Co-firing process of coal/biomass briquettes blends was investigated in a 7 MW grate boiler.The results of thermo-gravimetric and heating flow analysis show that co-combustion could reduce carbon value in residue and fly ash evidently.So the heat losses from solid incomplete combustion decreased and the boiler thermal efficiency increases.The distributions of coal/straw briquette blends improve the fire properties of coal and aggrandize the diffusion process of oxygen.At the same time,co-combustion of coal/straw briquette blends in grate boiler could restrain slag and fly ashes deposits.The biomass/coal mass ratio influences the temperature of furnace and the quantities of CO,NOx and SO2.The temperature of furnace and the quantities of NOx,SO2 would decrease with the increasing of biomass/coal mass ratio slightly,whereas the quantities of CO would increase.This paper suggests the thickness of blends should be 115~120 mm,the rotate speed of chain should be lower than 550 r/min and the biomass/coal mass ratio should be 23%~25%.Simultaneity,the mixing process of volatiles and air should be strengthened properly.Co-combustion of coal/straw briquette in grate boiler is a new approach of waste-to-energy technologies.