烘焙提升生物质燃料品质的研究

Improving the Quality of Biofuel by Torrefaction

以稻壳(RH)和木屑(PS)为原料,使用小型烘焙装置,研究了烘焙对生物质燃料品质的提升作用。相比原料,烘焙稻壳(TRH)和烘焙木屑(TPS)固定碳质量分数的最大上升量分别为7.18%和11.76%;C元素质量分数的最大上升量分别3.50%和5.80%,挥发分和O元素质量分数明显下降,H元素质量分数小幅降低;热值有所提升,最大提升幅度分别为11.1%(RH)和15.9%(PS);半纤维素大量分解,至300℃后烘焙的稻壳和木屑中半纤维素质量分数仅为2.41%和1.06%,降幅均超过90%,木质素质量分数显著增加,最大增幅分别为119%(RH)和208%(PS)。生物质烘焙后,内部纤维结构被破坏,可磨性提高,随着烘焙程度的加深,烘焙稻壳研磨后粒径在0.15 mm以下的颗粒显著提升;—OH和C—O等含氧官能团减少,疏水性提升,250℃烘焙30 min的稻壳和木屑的疏水性提升幅度分别为28.08%和25.66%。

The effect of torrefaction on the quality of biofuel was investigated through a small torrefaction experimental equipment with rice husk(RH)and pine sawdust(PS)as the raw materials.The results showed that torrefied rice husk and sawdust exhibited an increase in fixed carbon content by 7.18%and 11.76%,compared with the raw materials.And the C element content with the largest increased of 3.50%and 5.80%for rice husk and sawdust,respectively.The contents of volatile matter and O element decreased significantly,and the content of H element also decreased slightly.The calorific value increased by 11.1%(RH)and 15.9%(PS),respectively.The hemicellulose contents in the torrefied rice husk and sawdust after reaching 300℃were only 2.41%and 1.06%,respectively.The hemicellulose was decomposed both more than 90%.The relative content of lignin increased significantly,with the largest increases of 119%(RH)and 208%(PS),respectively.After biomass torrefaction,the internal fiber structure was destroyed and the grindability was improved.With the deepening of the torrefaction degree,the particles with the size below 0.15 mm increased significantly after torrefied rice husk being ground.The study found that oxygen-containing functional groups such as—OH and C—O were reduced,and the hydrophobicity of torrefied rice husk and sawdust increased by 28.08%and 25.66%,respectively,when torrefied at 250℃for 30 min.