小球藻热解油在Ni-Cu/ZrO2催化剂上的加氢脱氧

在小型固定床反应器中以Ni-Cu/ZrO₂为催化剂，对小球藻热解油进行催化加氢脱氧，以改善生物油性能。利用XRD、H₂-TPR、TG、NH₃-TPD等技术对催化剂进行了结构表征。结果表明，Cu的加入有效促进了Ni-Cu/ZrO₂催化剂活性相的表面分散，提高了该催化剂对小球藻热解油加氢脱氧反应的催化活性。在2 MPa、350 ℃反应条件下，随Cu/Ni的增大，Ni-Cu/ZrO₂的催化活性先升高后降低，Cu/Ni质量比为0.40时的催化性能最好，连续运行3 h后所得精制生物油脱氧率达82.0%。Ni-Cu/ZrO₂催化剂在反应过程中，表面结焦少，活性粒子及催化剂性能稳定，连续运行24 h后所得精制生物油脱氧率依然维持在77.0%以上。小球藻热解油经催化加氢脱氧所得的精制生物油，低位热值由31.5 MJ·kg^-1提高至35.0 MJ·kg^-1，40℃运动黏度由20.5 mm²·s^-1降至9.5 mm²·s^-1，且油品中水分更易于脱除。精制生物油中高级脂肪酸的含量减少，油品稳定性大幅提高。

Catalytic hydrodeoxygenation of fast pyrolysis bio-oil of chlorella over Ni-Cu/ZrO2 catalyst

The catalytic hydrodeoxygenation of bio-oil obtained by fast pyrolysis of chlorella over Ni-Cu/ZrO₂ catalyst was carried out in a fixed-bed reactor to improve the quality of the bio-oil. The catalysts were characterized by XRD, H₂-TPR, TG and NH₃-TPD techniques. The results showed that the addition of Cu promoted dispersion of active species, and increased catalytic hydrodeoxygenation activity of Ni-Cu/ZrO₂ catalysts. However, the activity went up first, and then went down with increase of Cu loading. A possible theoretical explanation was also given. At reaction conditions of 2 MPa and 350℃, the performance of Ni-Cu/ZrO₂ catalyst was stable and it made the oxygen content in the bio-oil decreased sharply. For the Ni-Cu/ZrO₂ catalyst with Cu/Ni mass ratio of 0.40, the efficiency of oxygen removal was 82.0% after 3 h reaction and larger than 77.0% after 24 h reaction. The heat value of upgraded bio-oil increased from 31.5 MJ·kg^-1 to 35.0 MJ·kg^-1, while the kinetic viscosity at 40℃ fell from 20.5 mm²·s^-1 to 9.5 mm²·s^-1 after hydrodeoxygenation reaction. In addition, the water in upgraded bio-oil could be removed easily. Furthermore, the stability of upgraded bio-oil was improved significantly due to the reduction of unstable acids.