Simulating particle-wall micromechanical interaction in entrained-flow slagging gasifiers by cold impact experiments

This paper deals with particle–wall interaction phenomena in entrained-flow slagging coal gasifiers. Different micromechanical char–slag interaction patterns may establish, depending on the stickiness of the wall layer and of the impinging char particle. Micromechanical interaction patterns were studied by means of an appropriate experimental apparatus which permitted to record a single particle/droplet impact on a flat surface. Montan wax was used to simulate, at nearly ambient temperature, the char–slag rebound characteristics upon colliding the wall. Particle–wall collision was described in terms of the particle restitution coefficient. In particular, the influence of the particle temperature and the impact angle as well as the impact velocity and the target surface on the rebound characteristics was studied. Results highlighted that the particle restitution coefficient decreased when enhancing operating conditions (temperature and impact velocity) able to promote plastic deformation upon particle impact.