Department of Chemical Engineering, University of Alicante, 99 P.O. Box, E-03080 Alicante, Spain.
Department of Chemical Engineering, University of Alicante, 99 P.O. Box, E-03080 Alicante, Spain.
Waste Manag. 2019 Nov;99:49-59. doi: 10.1016/j.wasman.2019.08.022. Epub 2019 Aug 28.
Hydrothermal liquefaction (HTL) of Animal By-Products (ABP) is a promising technology for their recycling and disposal. Different operating parameters have been studied to determine their influence on the process. Higher heating values of biocrudes ranging between 35 and 39 MJ/kg have been obtained showing a maximum yield of 61% at 225 °C. At low HTL temperature, the products are similar to those of rendering process and the biocrude is mainly formed by triglycerides and fatty acids in a 90:10 ratio, approximately. By increasing temperature, the free fatty acid yield increases, as well as amides and heterocyclic compounds as a result of the triglycerides and protein reactions. Between 250 and 290 °C a great difference in the composition of the biocrude obtained is observed. Water content also showed significant effects on the product yields. Large amounts of foams were obtained at low water contents that were minimised when it is increased. This is a very important feature to be considered for scaling up the phase separation process. Glycerine amount in the aqueous phase was remarkable, as a consequence of fat hydrolysis. Increasing pH to 9 increases the extraction of organics into the aqueous phase, whereas operating at pH 5 yields similar amounts of biocrude as compared with neutral pH, with a higher percentage of fatty acids. Reusing of the aqueous phase is necessary for the viability of the process and leads to increasing amounts of dissolved organics in the aqueous phase with the number of cycles, reaching a saturation level after three-four recycling rounds.
动物副产品（ABP）的水热液化（HTL）是一种很有前途的回收和处理技术。已经研究了不同的操作参数来确定它们对该过程的影响。获得的生物油高位热值在 35 到 39MJ/kg 之间，在 225°C 时产率最高可达 61%。在较低的 HTL 温度下，产物与炼油过程相似，生物油主要由三酰基甘油和脂肪酸以 90:10 的比例组成。随着温度的升高，游离脂肪酸的产率增加，同时由于三酰基甘油和蛋白质的反应，酰胺和杂环化合物也增加。在 250 到 290°C 之间，获得的生物油的组成有很大的差异。水含量对产品产率也有显著影响。在低水含量下会产生大量泡沫，当水含量增加时，泡沫会减少。这是在放大相分离过程时需要考虑的一个非常重要的特征。由于脂肪水解，在水相中会产生大量的甘油。将 pH 值提高到 9 会增加有机物向水相的萃取，而在 pH 值为 5 时，与中性 pH 值相比，生物油的产率相似，但脂肪酸的比例更高。为了使过程可行，需要重复使用水相，这会导致水相中的溶解有机物随着循环次数的增加而增加，在三到四个循环后达到饱和水平。
