黄贮玉米秸秆在全混流、竖向推流、折流板竖向推流反应器中的厌氧发酵特性

Characteristics of anaerobic fermentation in CSTR,VPF and BVPF for yellow storage of corn straw

为提高厌氧发酵的效率和秸秆利用率,将玉米干秸秆经过物理生物联合预处理形成黄贮玉米秸秆。本研究通过实验考察了黄贮玉米秸秆在竖向推流反应器(vertical plug flow,VPF)、全混流反应器(continuous stirred tank reactor,CSTR)和由本文作者课题组首创的折流板竖向推流反应器(baffled vertical plug flow,BVPF)中的厌氧发酵产气性能。结果表明,VPF反应器在有机负荷率(organic loading rate,OLR)为0.5gVS/(L·d)时运行良好,但提高OLR会出现出料困难的问题。CSTR有搅拌装置,所以反应器能够快速达到产气平衡。在OLR为1gVS/(L·d)时,BVPF达到稳定所需时间比CSTR多7天,但最终趋于稳定时CSTR和BVPF反应器的单位挥发性固体(volatile solid,VS)的日产气量分别为390.9mL和382.4mL。在OLR为2gVS/(L·d)时,BVPF达到稳定所需时间仅比CSTR多2天,稳定时CSTR和BVPF反应器的单位VS日产气量分别为291.3mL和294.9mL。此外,3种反应器在运行阶段,pH和VFA/TIC值都能维持稳定。在提高OLR后,BVPF和CSTR能够达到新的平衡状态。本实验结果表明VPF反应器只能用于低OLR的情况;CSTR达到稳定状态所需的时间较短,但CSTR和BVPF在稳定运行时的产气效率基本持平。由于BVPF的耗能量、耗水量低,因此该类反应器有良好的商业应用前景。

In order to improve the efficiency of anaerobic fermentation and the utilization rate of straw,the corn straw could be pretreated with physical and biological methods to form yellow storage of corn straw(YSCS).In this study,the fermentation performances of YSCS in different kinds of reactors were comprehensively investigated,including vertical plug flow(VPF) reactor,continuous stirred tank reactor(CSTR) and baffled vertical plug flow(BVPF) reactor which was upgraded from VPF reactor.In the VPF reactor,YSCS could perform well when the organic loading rate(OLR) was 0.5 gVS/(L·d).However,it was difficult to discharge the materials with the increase of OLR.Besides,CSTR had a stirring sector,and thus the reactor could reach gas production equilibrium quickly.When OLR was 1 gVS/(L·d),the time required for BVPF to reach stability was 7 days longer than that of CSTR.After it finally reached stability,the gas production per volatile solid(VS) in CSTR and BVPF reactors were 390.9 mL and 382.4 mL,respectively.When OLR was 2 gVS/(L·d),BVPF needed two more days to reach equilibrium comparing to CSTR,and the gas production per VS of CSTR and BVPF reactors were 291.3 mL and 294.9 mL,respectively.In addition,pH and VFA/TIC values of all three reactors remained stable during the operation stage.After the increase of OLR,BVPF and CSTR were able to reach new equilibrium.These results indicated that VPF reactor could be used under the condition of low OLR.The time required for the CSTR to reach a steady state was short,but the gas production efficiency of the CSTR and BVPF was basically the same during stable operation.In conclusion,owing to the lower energy and water consumption,BVPF would have a promisingly commercial application prospect.