两级双液相萃取棉籽联产生物柴油和无毒棉粕

Combined production of biodiesel and nontoxic cottonseed meal from cottonseed using two-step two-phase solvent extraction

采用两级双液相萃取棉籽联产生物柴油和无毒棉粕。与一步双液相萃取法处理棉籽技术相比,该法在保持甲醇总量不变的基础上,将双液相萃取分为两级进行,二级萃取用的甲醇在完成了萃取功能以后再作为酯交换反应原料使用,不再需要重新加入新鲜的甲醇进行反应,减少了甲醇用量和溶剂再生的负荷。得出酯交换反应的最佳条件为:一级萃取甲醇用量为甲醇总量的60%,催化剂用量为棉籽油质量的1.1%,反应温度60℃,反应时间120 min。在最佳反应条件下,生物柴油产物中脂肪酸甲酯含量可达98.8%;萃取棉粕中游离棉酚含量为0.013%,符合美国国家棉籽产品协会的贸易标准,可用作动物饲料等。

Biodiesel and nontoxic cottonseed meal were co-producted from cottonseed using two-step two-phase solvent extraction （ TS-TSE） . Comparing with one-step two-phase solvent extraction of cottonseed, TS-TSE was conducted in two steps on the basis of invariant total dosage of methanol. Methanol from the second-step extraction of TS-TSE could be used as raw material in transesterifica-tion, and there was no need for fresh methanol, so methanol dosage and regeneration load of solvent re-duced. The optimal transesterification conditions were obtained as follows：methanol dosage in the first-step extraction 60% of total methanol dosage, catalyst dosage 1. 1% （ based on the mass of cottonseed oil） , reaction temperature 60℃and reaction time 120 min. Under these conditions, the content of fatty acid methyl ester in the biodiesel product reached 98. 8%, and the content of free gossypol in cottonseed meal extracted was 0. 013%, which was accord with USA National Cottonseed Products Association standard and suitable for being used as animal feed.