The burning characteristics of interacting coal particles in a convective flow are numerically investigated at various Reynolds numbers. The transient combustion of 2-dimensionally arranged particles, both the fixed particle distances of 5 radii to 20 radii horizontally and 4 radii to 24 radii vertically, is studied. The results obtained from the present numerical analysis indicate that the transient flame configuration and retardation of particle temperature augmentation with the horizontal or vertical particle spacing substantially influence devolatilization process and carbon conversion ratio of interacting particles. Volatile release and carbon conversion ratio of the second particle with decreasing horizontal and vertical particle spacing decrease gradually, whereas those of the first particle with decreasing vertical particle spacing increase due to flow acceleration. When the vertical particle spacing is smaller than $6R_0$, volatile release and carbon conversion ratio of the second particle decrease due to reduction of flame penetration depth and interference of oxygen diffusion by the first particle.