摘要
分别以费托合成直馏柴油和异构柴油为原料,通过尿素/硫脲对正构烷烃和异构烷烃进行分离,从而提高产品附加值。通过尿素或硫脲法分离直馏柴油中的正/异构烷烃实验可以看出,采用尿素法一次脱蜡得到的产品中正构烷烃含量达到97.0%(质量分数,下同),二次脱蜡得到的正构烷烃含量达到98.0%;通过硫脲法分离正/异构烷烃,产品中正构烷烃含量为96.5%,但硫脲量使用量降低。通过对尿素法分离异构柴油的研究,可以看出尿素量增加有利于降低异构柴油的凝点。对比尿素法和硫脲法的分离结果,可以看出,尿素和硫脲均可与正/异构烷烃反应,但稳定性存在差异。相对而言,尿素与高碳异构烷烃或低碳正构烷烃形成络合物更稳定,硫脲与高碳正构烷烃或低碳异构烷烃形成络合物更稳定。
In order to improve additional value of straight-run diesel and heterogeneous diesel in F-T synthesis, normal and isomerous hydrocarbon were separated by urea/thiourea inclusion method, respectively. By studying the separation process of straight-run diesel, optimum experimental conditions(20 g urea, 200 mL anhydrous ethanol, 20 g raw oil, 30 ℃) were obtained. It can be seen that n-paraffin content in complex phase product could reach 97.0% by primary urea separation and add up to 98.0% by secondary urea separation at the optimum experimental conditions. Separation of straight-run diesel by thiourea inclusion method was also studied. The content of n-paraffin in the product was about 96.5%, but the amount of thiourea was decreased. In separation process of heterogeneous diesel by urea inclusion method, the increase of urea addition can reduce the condensation point. Comparing the result of urea and thiourea separation, urea is more stable with low-carbon n-paraffin and high-carbon iso-paraffin, while thiourea is more stable with high-carbon n-paraffin and low-carbon iso-paraffin.
引文
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