METHOD FOR DIRECT DISPOSAL OF PLASTIC WASTE BY CHEMICAL RECYCLING IN A PARTIAL OXIDATION PROCESS

摘要

The invention relates to a method for the chemical recycling of plastic waste materials by means of an improved partial oxidation, gasification process comprising gasification, waste heat recovery and carbon removal in a scrubber unit during formation of a soot water slurry containing the unburned carbon and ash. The plastic waste material and oil feedstock are fed directly into the reactor together. Unburned carbon and ash are separated and removed completely from the gasification process thereby establishing a continuous once-through partial oxidation without the need to recirculate carbon/ash residue. The soot/water slurry resulting from the carbon removal step is filtered to form a filtercake containing at least 20 % dry matter, said filtercake being processed into a reclaimable ash. Two types of polyelectrolytic flocculating agents are added to the soot slurry prior to filtration, one being cationic and the other anionic. The flocculants are added in a total amount of 60-100 ppm and at a ratio of cationic: anionic polyelectrolyte of 1-5 : 0.5-2.