[Objective] Online atmospheric-pressure laser-ignition calorimeters perform effectively in measuring high-quality coals with low ash content and relatively high calorific values. However

for high-ash

difficult-to-burn coals

an insufficient burnout ratio severely restricts measurement accuracy. Therefore

there is an urgent need to explore efficient atmospheric combustion intensification methods to improve the burnout ratio of coal samples during instrument operation and expand the fuel adaptability of the instrument. [Methods] Based on the existing calorimeter architecture

an atmospheric combustion experimental testing system was established. A diverse set of pulverized coal samples encompassing various coal quality parameters was selected to comparatively study the effects of different intensification techniques on the combustion and burnout characteristics. The investigated methods included the regulation of the oxygen flow rate and jet velocity

the addition of a thermal insulation layer around the crucible to minimize heat dissipation

and the introduction of a novel active mechanical agitation device. Specifically for the mechanical agitation strategy

which utilizes a tiltable and rotatable crucible

a multi-parameter coupled optimization was conducted using an orthogonal experimental design to systematically evaluate the interactive effects of critical operating parameters. [Results] The experimental research indicates that conventional approaches

such as oxygen parameter regulation and thermal insulation

yield very limited improvements in the burnout ratio of high-ash coal samples

as they fail to eliminate the oxygen diffusion barrier. In contrast

the active mechanical agitation strategy based on continuous crucible tilting and rotation proved to be highly effective. Through the orthogonal experiment optimization

the optimal operating conditions were precisely determined to be a crucible tilt angle of 45°

a rotation start time of 60 s

which corresponds to the early stage of the main combustion process

and a rotation speed of 30 r/min. Under these specific conditions

the continuous mechanical tumbling dynamically and effectively disrupts the formation of the dense ash shell structure

thereby significantly intensifying gas-solid contact between the unreacted carbon particles and the oxidizing atmosphere. [Conclusion] The combustion intensification method driven by the mechanical agitation of the tilted and rotating crucible expands the applicable fuel range of this calorimeter from the original high-quality coals(ash content 10%

calorific value 25 000 J/g) to a much broader spectrum of coals(ash content 60%

calorific value 11 000 J/g). This research significantly enhances the coal type adaptability of the instrument and provides an efficient and reliable technical pathway for the design of atmospheric online calorimeters.