粗磨粉碎对秸秆厌氧发酵产沼气的影响

Effects of coarse grinding machine shattered straw on biogas anaerobic fermentation

通过对高效粗磨机粉碎秸秆(RS-HECGM)和传统的切割机粉碎秸秆(RS-CTM)在酸解处理、厌氧消化、能耗、粒径分布等方面的比较,探究高效粗磨机粉碎的优劣。与RS-CTM相比,RS-HECGM酸解后半纤维素降解率提高了13.23%。厌氧发酵后,RS-HECGM中纤维素和半纤维素的降解率分别达到58.85%、48.47%,比RS-CTM分别提高了23.58%、29.15%;累积产气量达到10 375 mL,产气率为0.3127 L/gVS,较RS-CTM分别提高了17.43%和16.21%。RS-CTM发酵体系的总固体质量分数由发酵前的6.03%下降至3.94%,而RS-HECGM发酵体系的总固体质量分数则降至3.27%。高效粗磨机的能耗为68.75kW.h/t,虽较切割机高8.56%,但处理量却是切割机的2.67倍,为0.8t/h。RS-HECGM粒径分布较为均匀,10 mm以下的稻草占总量的74.08%;而RS-CTM粒径较大,10 mm以下的稻草仅占总量的39.74%。使用10L发酵罐验证,与添加RS-CTM的发酵体系相比,添加RS-HECGM的发酵体系在产气率提升19.01%的前提下,厌氧消化搅拌能耗降低了56%。

High Efficient Coarse Grinding Machine （HECGM） is a new type of shredder for processing agricultural crop-waste, such as rice or wheat straw. The present authors have done a comparative experimental study to find the advantages and disadvantages of crushing the above said straw while using the traditional cutting machine （CTM） with HECGM when it was treated in acid solution, anaerobic digestion, energy consumption and particle size distribution. Through the acid treatment, the hemicellulose destruction rate of the HECGM-treated rice straw can be increased by 13.23% in comparison with that of the CTM-treated rice straw. Through anaerobic fermentation, the cellulose and hemicelluloses destruction rate of the straw treated by HECGM could respectively reach 58.85%, 48.47%, that is an increase of a rate of 23.58%, 29.15% in comparison with it being treated by CTM. The biogas yield by using the HECGM-treated rice straw can be 17.43% higher and 16.21% higher as compared with CTM-treated. And in turn the cumulative biogas production is expected to achieve 10375 mL with biogas yield rising to 0.3127 L/gVS. However, the total solid content of fermentation system by using CTM-treated rice straw tends to reduce to 3.94% from 6.03% during the anaerobic fermentation. In contrast, with HECGM-treated rice straw, the total solid content of fermentation can be found vary from 6.03% to 3.27%. In addition, the energy consumption of HECGM is 68.75 kW＆middot;h/t, greater than 8.56% as compared with CTM. However, the treating capacity of HECGM can be increased to 0.8 t/h, that is, 2.67 times as that of CTM. With the HECGM-treated rice straw and the particle size of the distribution being equal, 74.08% of the straw would be found shorter than 10 mm. Whereas the particle size distribution of CTM-treated straw is found between 10-20 mm, only 39.74% of the straw turns to be shorter than 10 mm. Tested by using the 10 L fermentation system, the HECGM-treated rice straw tends to promote the biogas yield of 19.9% as compared with fermentation system adding the CTM-treated rice straw on the condition to energy saving of 56%. Thus, the experiments demonstrate that the pretreated rice straw with HECGM is likely to be a promising method for improving biogas production and decreasing energy consumption.