Semi-coke is a low-volatile solid carbonaceous fuel, which is quite difficult to combustion individually. Co-processing semi-coke with bituminous coal has the potential for efficient and clean utilization of powdery semi-coke, while the co-pyrolysis is an important step and the physical-chemical properties of residual solid products yield great influences on subsequent combustion characteristics and NO_x formation. However, less work, if any, has aimed at the co-pyrolysis of bituminous coal and semi-coke, and the synergistic mechanisms on physical and chemical properties of solid products have yet to be fully understood. Even limited oxygen may generate remarkable influences on co-pyrolysis behaviors. In addition, limited oxygen is possibly present during pyrolysis process, which has been rarely paid attention to. In this work, the physicochemical properties of solid co-pyrolysis products of bituminous coal and semi-coke were investigated experiment, while the effects of multiple atmosphere composition were also emphasized, including CO₂/N₂ atmosphere, N₂ atmosphere with limited O₂, and CO₂/N₂ atmosphere with a little O₂. The results indicate that the dehydrogenation and polycondensation of bituminous aromatics are observed over 700 °C. The semi-coke and bituminous coal have the synergistic effect in the co-pyrolysis process. In N₂ atmosphere with little oxygen, the pore development mainly occurs as the O₂ concentration is below 3%. The residual char is over-ablated with the further increasing oxygen content. When the atmosphere contains O₂, a small number of nitrogen oxides are formed. The present work can provide a scientific guidance for the utilization of semi-coke in large-scale and the design of power plant co-fired with semi-coke. This work is also beneficial to improve combustion reactivity of blended fuel, determine the optimal blending ratio and control NO_x emissions.

半焦是一种低挥发性固体碳质燃料，单独燃烧非常困难。半焦与烟煤协同处理具有高效清洁利用粉状半焦的潜力，而共热解是一个重要步骤，残余固体产物的理化性质对后续燃烧特性和NO _X形成。然而，针对烟煤和半焦共热解的研究较少，固体产品理化性质的协同机制尚未完全了解。即使是有限的氧气也可能对共热解行为产生显着影响。此外，在热解过程中可能存在有限的氧气，这很少受到关注。本工作对烟煤和半焦固体共热解产物的理化性质进行了实验研究，同时强调了多种气氛组成的影响，包括CO ₂ /N ₂气氛、N ₂气氛和有限O ₂ , 和 CO ₂ /N ₂气氛与一点O ₂。结果表明，在 700 °C 以上观察到沥青芳烃的脱氢和缩聚反应。半焦和烟煤在共热解过程中具有协同作用。在含氧量较少的N ₂气氛中，孔隙发育主要发生在O ₂浓度低于3%时。随着氧含量的进一步增加，残留的炭被过度烧蚀。当大气中含有 O ₂，形成少量氮氧化物。该工作可为半焦的规模化利用和与半焦混烧的电厂设计提供科学指导。这项工作也有利于提高混合燃料的燃烧反应性，确定最佳的混合比，并控制NO _X的排放。