废聚苯乙烯的热裂解与催化裂解

对废聚苯乙烯(WPS)的热裂解与催化裂解进行了研究,考察了反应温度、反应时间及催化剂用量对裂解率、产油率和各产物选择性的影响。实验结果表明,WPS的裂解产物主要是苯乙烯,副产物为苯、甲苯、乙苯和α-甲基苯乙烯。无论是热裂解还是催化裂解,裂解率和苯乙烯选择性均随反应温度的升高而增大;延长反应时间,裂解率增大,但苯乙烯选择性下降。在反应温度380℃、反应时间60min的条件下,催化剂用量(相对于WPS的质量分数)由2.0%增至8.0%时,裂解率由75.0%降至61.2%,产油率在90.0%以上;副产物α-甲基苯乙烯的选择性与催化剂的用量成正比。WPS裂解制取苯乙烯具有工艺简单、成本低等优点,具有较好的经济效益和社会效益。

Catalytic Cracking and Thermal Cracking of Waste Polystyrene

Both catalytic cracking and thermal cracking of waste polystyrene(WPS) were investigated.Fluid catalytic cracking catalyst from refinery was used in catalytic cracking of WPS.Effects of reaction temperature,reaction time and catalyst dosage on conversion of WPS,oil yield and selectivities of liquid products were studied.The products of both crackings mainly and similarly comprised styrene,benzene,toluene,ethyl benzene and α-methyl styrene.In both crackings,conversion of WPS and selectivity to styrene increased with increasing of reaction temperature.Although prolonging the reaction time also led to rising of conversion,drop of selectivity to styrene accompanied.For catalytic cracking when the reaction was carried out at 380 ℃ for 60 min and the mass fraction of catalyst(based on WPS) increased from 2.0% to 8.0%,the conversion went down from 75.0% to 61.2% and yield to oil kept above 90.0%.Selectivity to α-methyl styrene was directly proportional to mass fraction of catalyst.Both crackings of WPS have high economical and social benefits due to its simplicity and low cost.