A PHYSICOCHEMICAL STUDY OF CARBONIZATION PHASES .2. QUENCHING EXPERIMENTS AT THE PILOT-SCALE

Previous experiments carried out on several carbonization phases showe d a relationship between tar migration and the coking pressure, In the present study, tests analogous in principle to the previous ones were conducted at a pilot scale with 400 kg coal charges. Two coals were u sed: C28, which leads to no pressure (''safe''), and C19, which induce s pressure (''dangerous''). N-methyl-2-pyrrolidinone (NMP) extractions from the carbonization phases of the two coals confirm that tar migra tion is dependent on the nature of the parent coal, i.e. whether ''saf e'' or ''dangerous'', In the case of dangerous coal, the impregnation of non-coked coal by tars has been evidenced, In relation to this phen omenon, increased coking pressure is likely to develop due to the enri chment of non-transformed coal by volatile matter, as well as to the d rop in permeability of this phase, It is also suggested that heavy tar s clog up the pores of the semi-coke of dangerous coals.