两种类型生物制氢反应器的运行及产氢特性

为探求反应器型式对发酵法生物制氢过程的影响,分别采用连续流搅拌槽式反应器(CSTR)和颗粒污泥膨胀床反应器(EGSB)接种厌氧活性污泥,从糖蜜废水中制取氢气.运行中控制温度为35℃,通过缩短水力停留时间(HRT)和增加进水COD质量浓度的方式逐渐提高容积负荷(OLR),分别对CSTR系统和EGSB系统的产氢速率、pH、液相末端产物及生物量进行研究.结果表明,两个系统中,产氢速率均随OLR提高而逐渐升高.CSTR的最佳产氢OLR为25~35 kg/(m3.d),而EGSB的最佳产氢OLR为70~80 kg/(m3.d);此时,CSTR系统的最大产氢速率为6.21 L/(L.h),EGSB系统的最大产氢速率可达18.0 L/(L.h).稳定运行期,EGSB系统的生物量为27.6 gVSS/L,而CSTR的生物量仅为7.8 gVSS/L,说明较高的生物量是生物制氢反应器稳定运行和高效产氢的关键.两个系统均可形成乙醇型发酵,说明发酵类型的形成不受反应器型式影响.与CSTR反应器相比,EGSB反应器具有更好的耐酸能力.

Operation and hydrogen production characteristics in different types of reactors

CSTR reactor(suspended growth) and EGSB reactor(attached growth) were used to study the influence of biohydrogen production process through different types of reactors.Anaerobic activated sludge was used as inocula and molasses wastewater was selected as substrate.Keeping temperature at 35 ℃,the hydrogen production rate(HPR),pH value,liquid end products and biomass were examined to study the operation characteristics of the two reactors with the organic loading rate(OLR) adjusted firstly by increasing the COD concentration and then by shortening the hydraulic retention time(HRT).The results showed that HPR increased gradually with the increase of OLR.The optimal OLRs for CSTR reactor and EGSB reactor were 25-35 kg/(m3·d) and 70-80 kg/(m3·d) with the maximum HPR of 6.21 L/(L·h) and 18.0 L/(L·h),respectively.When in stable running periods,EGSB reactor maintained a high biomass concentration of 27.6 gVSS/L,while that was 7.8 gVSS/L for CSTR reactor.It is indicated that high biomass concentration effectively contributes to the high HPR and high stable running of hydrogen producing reactor.Both of CSTR reactor and EGSB reactor form ethanol-type fermentation,which suggests that fermentation type is not influenced by reactor types.Moreover,EGSB reactor presents more tolerance to low pH compared with CSTR reactor.