Needle coke formation derived from co-carbonization of ethylene tar pitch and polystyrene

Ethylene tar pitch was co-carbonized with waste polystyrene to prepare needle coke. The modified properties of mesophase, which were greatly improved due to increasing naphthenic and other alkyl content, availed the formation of needle coke with high quality. The coefficient of thermal expansion value was decreased from 3.2 × 10 −6/°C to 0.3 × 10 −6/°C and the optical texture of the coke was changed from coarse mosaic texture to flow domain of high uniaxial orientation after adding waste polystyrene into ethylene tar pitch. The low viscosity of the mesophase pitches favored the development of mesophase and highly uniaxial arrangement. The increase in alkyl group content greatly improved characteristics of the needle coke.