Abstract The hydro-liquefaction of high-density polyethylene (HDPE) was studied in the absence of a solvent. The influence of reaction temperature (400–440 °C), initial H2 pressure (1–4 MPa), and reaction time (2–6 h) on the product was investigated using Ni/Al2O3 as a catalyst. Results showed that increased reaction temperature and time promoted hydrocarbon cracking, thereby favoring the enhancement of C7–C16 selectivity, whereas the high initial H2 pressure (4 MPa) preferentially facilitated the production of C17–C27 hydrocarbons and improved alkene hydrogenation. The effect of catalyst support (Al2O3, SAPO-11, and HZSM-5) was also examined. Al2O3 presented the highest liquid yield because of its weak acidity, with the liquid product dominated by n-alkanes (78.88%), whereas the yield of the liquid obtained from HZSM-5 as a catalyst support was the lowest, and aromatics was the major component (56.75%). SAPO-11 exhibited excellent selectivity for iso-alkanes, which improved the quality of the liquid oil. Meanwhile, liquid oil obtained using SAPO-11 was compliant with commercial jet-fuel standards and can be directly used as a jet-fuel additive. From this perspective, the hydro-liquefaction is a technology with potential for energy recovery from waste plastic.

中文翻译：

---

高密度聚乙烯加氢液化产品工艺参数评价

摘要 研究了无溶剂下高密度聚乙烯 (HDPE) 的加氢液化。使用 Ni/Al2O3 作为催化剂研究了反应温度 (400–440 °C)、初始 H2 压力 (1–4 MPa) 和反应时间 (2–6 h) 对产物的影响。结果表明，提高反应温度和时间促进烃类裂解，从而有利于提高 C7-C16 选择性，而高初始氢气压力（4 MPa）优先促进 C17-C27 烃的生产并改善烯烃加氢。还检查了催化剂载体（Al2O3、SAPO-11 和 HZSM-5）的影响。Al2O3 呈弱酸性，液体产率最高，液体产物以正构烷烃为主（78.88%），而以HZSM-5为催化剂载体得到的液体收率最低，芳烃是主要成分（56.75%）。SAPO-11 对异烷烃表现出优异的选择性，提高了液体油的质量。同时，使用 SAPO-11 获得的液态油符合商用喷气燃料标准，可直接用作喷气燃料添加剂。从这个角度来看，加氢液化是一项具有从废塑料中回收能量的潜力的技术。