Research On The Initiation And Operation Of Mega Scale CSTR Biogas Project With The Material Of Corn Stover

Environmental Pollution and the Energy Dilemma have been the main barriers of Chinese rapid economy development.As a huge agricultural country,there are abundant agricultural biomass resources with the data of about 0.75 billion tons per year,among which 0.14 billion tons can be collected,anaerobically fermented and turned into 21 billion cubic meters BNG(Bio-Natural Gas).This equals to 9.1%of 2017 National Natural Gas Consumption.Besides,the livestock manure,municipal sludge,kitchen waste,and industrial organic waste can also be turned into biogas or BNG.It makes the large amount of biomass resources.In the recent 10 years,the Chinese government has taken out more than 40 billion Yuan to support the construction of biogas projects,but the problems like slow project initiation and low material usage are the limitations to develop the biogas project.In this study,the initiation and operation of mega scale CSTR Biogas Project with the material of corn stover were studied,the conclusions are as followed:1.The methods of concentration gradient and continuous expansion were adopted to study how to start up the anaerobic fermentation system rapidly using biogas slurry,cow manure and sludge as inoculum.Research showed that both concentration gradient method and continuous expansion method could successfully start up the anaerobic fermentation system with the inoculation of lOgTS·L-1,and the former could avoid the acidification,be more excellent than the latter,and take less time.Combined inoculum of biogas liquid and cow manure prevailed over those single-component inoculums like biogas liquid,cow manure and sludge.When the organic loading was 80gTS·L-1,VLR(Volume loading rate)in digesters initiated by combined inoculum was 4.5%-16.3%more than by single-component inoculum,and the system was much more stable.2.Concentration gradient method was adopted to start up mega scale CSTR biogas project.Research showed that it's quite fit for the project,the fermentation system was quite stable and safe during the initiation,and the more inoculum,the faster startup.3.Systematic research on the material of corn stover in mega scale CSTR biogas project showed:on monthly average OLR of 0.38-2.78KgTS·(m3·d)-1,the anaerobic fermentation system was stably operated,monthly average pH was 7.1-7.4,monthly average methane content was 50.7%-55.6%,and the ammonia nitrogen and the alkalinity were all in reasonable threshold value ranges.According to Spearman correlation analysis,higher value of TS concentration and pH led to higher methane content.The higher value of TS concentration meant the faster accumulation of ammonia nitrogen,and the more buffer ability of the fermentation system.On the OLR of 2.78 Kg TS·(m 3·d)-1,TS concentration of 12%,HRT of 43 days,the anaerobic fermentation system performed well,and the pH was 7.2,VLR was 1.03m3·(m3·d)-1,methane content was 52.5%,the biogas yield was 411 m3·t-1TS,and the methane yield was 216 m3·t-1TS.4.High-throughput sequencing of microflora in super mega CSTR biogas project with the material of corn stover indicated high microbial diversity and species richness.Phylum-level predominant bacteria included Chloroflexi,Firmicutes and Bacteroidetes.Phylum-level predominant archeobacteria included Euryarchaeota,Crenarchaeota.