煅烧Mg-Al水滑石催化油脂裂化的性能研究Performance of calcined Mg-Al hydrotalcite as catalyst for oil cracking

Abstract

旨在为固体碱催化剂催化油脂裂化制备生物基燃料油提供参考，采用共沉淀法制备Mg-Al水滑石，煅烧后作为催化剂，催化菜籽油裂化制备生物基燃料油。采用XRD、FT-IR、SEM等分析方法对催化剂进行表征分析，并通过对其催化油脂裂化液体产物收率、酸值、皂化值的分析，对其催化性能进行评价，同时采用GC-MS分析了液体产物的组成。结果表明：当催化裂化温度为470 ℃，镁铝比为3∶ 1时，液体产物的收率（60.20%）较高，酸值（KOH）（1.1 mg/g）和皂化值(KOH)(9.3 mg/g)较低；催化剂的最佳使用次数为5次；催化剂的镁铝比为3∶ 1时，液体产物的烷烃和烯烃含量较高。煅烧后的Mg-Al水滑石虽然部分结构遭到破坏，但仍具有很高的结晶度和碱活性，在一定程度上提高了生物基燃料油的品质。 In order to provide a reference for the preparation of bio-based fuel oil by oil cracking catalyzed with solid base catalyst, the Mg-Al hydrotalcite was prepared by co-precipitation method, and then was calcined. The calcined Mg-Al hydrotalcite was used as catalyst to produce bio-based fuel oil by oil cracking.The catalyst was characterized by XRD, FT-IR and electron microscope, and its catalytic performance was evaluated by analyzing the yield, acid value and saponification value of liquid product produced by oil cracking. In addition, the composition of the liquid product was analyzed. The results showed that under the conditions of cracking temperature 470 ℃and ratio of magnesium to aluminum in catalyst 3∶ 1, the yield of liquid product(60.20%) was higher, the acid value (1.1 mgKOH/g)and saponification value(9.3 mgKOH/g) of liquid product were lower. The optimal using times of catalyst were 5. The contents of alkanes and olefins in the liquid product were higher when the ratio of magnesium to aluminum in the catalyst was 3∶ 1. Although part of the structure of calcined Mg-Al hydrotalcite was destroyed, it still had high crystallinity and alkali activity, which improved the quality of bio-based fuel oil to a certain extent.

Keywords

• 水滑石；催化裂化；油脂；生物基燃料油
• hydrotalcite; catalytic cracking; oil; bio-based fuel oil