Palma Alberto, Loaiza Javier Mauricio, Díaz Manuel J, García Juan Carlos, Giráldez Inmaculada, López Francisco
Research Center in Technology of Products and Chemical Processes, PRO2TECS-Chemical Engineering Department, "El Carmen" Campus, University of Huelva, Huelva, Spain.
Prof. J.C. Vílchez-Martín" Chemistry Department, El Carmen" Campus, University of Huelva, Huelva, Spain.
Biotechnol Biofuels. 2021 Apr 8;14(1):89. doi: 10.1186/s13068-021-01930-0.
Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production.
The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6-9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses.
Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.
燃烧速生树木用于能源生产可成为煤炭燃烧的有效替代方案。因此，木质纤维素材料可用于获取高附加值化学品，其储量丰富、易于再生且通常价格低廉。在本研究中，对三种不同作物（多花金雀儿、异叶银合欢和三倍体泡桐）的植物生物质进行酸水解提取半纤维素的过程进行了建模，并将所得固体残渣用于能源生产。
研究了木质纤维素原料的性质以及用于提取半纤维素部分的操作条件对后续燃烧过程的热容量和活化能的影响。发现燃烧过程的热功率和活化能明显取决于原料中的半纤维素含量。因此，半纤维素含量低会导致酸水解阶段后能量产率的增加较低。该过程还受到酸水解处理操作条件的影响，相对于起始原料，固体残渣的总热值提高了0.6 - 9.7%。此外，多花金雀儿（银荆）和三倍体泡桐（泡桐）酸水解残渣的燃烧活化能明显低于起始原料，随着转化率的提高以及酸水解中温度和酸浓度的增加，差异增大。银荆和泡桐酸水解固体残渣的燃烧活化能随着转化率的提高以及酸水解处理中温度和酸浓度的增加而显著降低。由于异叶银合欢（银合欢）半纤维素含量低，未观察到类似趋势。
对银荆、银合欢和泡桐进行酸水解可得到含有大量半纤维素的可增值液体以及热功率增加的固体残渣，该固体残渣适合通过燃烧进行高效增值利用。富含半纤维素和富含木质素的部分有许多潜在应用，例如作为3D打印生物基原料的多组分、用于能源和其他增值化学品。
