Exploration on feasibility of novel purification-combustion technology in activation, high-efficiency combustion and NOx emission reduction of typical low-quality carbonaceous fuels

Abstract

To enhance the utilization efficiency of low-quality carbonaceous fuels and reduce NO_x emissions during their utilization, exploring innovative technologies for clean and effective combustion was essential. Purification-combustion technology exhibited great advantages in fuel activation, high-efficiency combustion and NO_x emission reduction. The novelty of this study was associated with an in-depth analysis of the feasibility of this technology in clean and effective combustion of low-quality carbonaceous fuels. This study investigated two-stage fuel modification, combustion and NO_x emission characteristics of bituminous coal, semi-coke and lean coal in a 30-kW purification-combustion test bench and compared their differences of carbonaceous fuels with different qualities. Purifying burner exhibited significant benefits in enhancing particle structure and reactivity of low-quality carbonaceous fuels, including specific surface area, pore diameter, pore volume, carbon microcrystalline structure and fuel conversion rates. The differences in these indexes of the reductive chars between bituminous coal and the other two low-quality carbonaceous fuels was smaller than those of the activated char, proving the advantages of purification-combustion on the modification of low-quality carbonaceous fuels. Additionally, purification-combustion technology exhibited great advantages in realizing clean and effective combustion of low-quality carbonaceous fuels. NO_x emissions remained below 100.00 mg/m³ when semi-coke and lean coal were used as raw materials, and they were close to those with bituminous coal as raw material. By contrast, though the difference in combustion efficiency was larger, it still remained at about 98.00 % when semi-coke and lean coal were used as raw materials.