Study On The Fresh Green Plant Crushing Equipment And Its Mixed Anaerobic Fermentation

Sweet potatoes and potatoes,as China’s major food crops,would produce a lot of vines and straw in the production process.Fresh green vines became corrupted easily and most of the dry straw was burned by farmers,which not only cause serious environmental pollution,but also cause waste of resources.At present,the most widely used agricultural waste disposal method is biogas fermentation technology,straw materials need to be pretreated in order to normal production of biogas.However,the current forage grinders have some defects,such as poor adaptability to raw materials of biogas engineering,huge supporting power,low productivity,lower shredder speed and the difference between installation angle of moving knife,which directly result in poor broken effect of fresh green plants.In the anaerobic fermentation,the traditional mixed anaerobic fermentation use different livestock manure and dried straw to produce biogas,there are some disadvantages in that fermentation process,such as floating crust,reaction start slowly,long reaction cycle and heat and mass transfer poorly.Therefore,it is of great theoretical and practical significance to study fresh green plant crushing equipment and the performance of anaerobic fermentation of pig manure and fresh sweet potato vine mixture& potato vine with different mixing ratios at different temperatures。Research combined with national major projects "rural biogas centralized gas supply technology integration and ancillary equipment and demonstration(201403019)".The contents of the research are as follows: researching and designing of fresh green plant crushing equipment;studing mixed anaerobic fermentation of pig manure and fresh sweet potato rattan or fresh potato vine;influences of crushing length of fresh green material to mixed anaerobic fermentation.The results as follows:(1)In the mixed anaerobic fermentation test,there was no significant difference between the cumulative gas production of length of 10 mm and 30 mm fresh material Therefore,9ZF-3 type of green plant shredder design is reasonable and meet the design requirements.(2)In the mixed anaerobic fermentation experiment of pig manure and fresh sweet potato vine or fresh potato vine,the cumulative gas production the treatment group is higher than than that of single material,and the variance analysis found significant difference.They both had the highest cumulative gas production at 35 ℃,pig manure and fresh material ratio of 1: 2 the,respectively: 10033 mL,8913mL.In each experiments,the correlation analysis among daily gas production,volatile fatty acid(VFA),pH,methane volume fraction and carbon dioxide volume fraction.The correlation between daily calorific value and other indexes is not significant,there is a significant positive correlation between VFA and pH,pH is positively correlated with methane fraction,there is a significant negative correlation between the volume fraction of methane and the volume fraction of carbon dioxide.(3)With the increase of the proportion of fresh materials,there is a difference between the daily production and cumulative gas production of anaerobic fermentation pig manure mixed with fresh sweet potato vines and fresh potato vines at different temperatures(35℃,45℃ and 55℃).The changes of indicators in the reaction system are as follows: pH increased at first and then decreased,VFA decreased at first and then increased,methane content decreased,carbon dioxide content increased.With the increase of temperature,the indicators in the reaction have changed,VFA and pH changes in the opposite direction,methane content increase at first and than rise,carbon dioxide content increase at first and than decreased.(4)At the same temperature,except 50℃,characteristics of anaerobic fermentation of different fresh materials mixed pig manure mixed are different.Compared with the anaerobic fermentation of pig manure and fresh sweet potato,pigs and fresh potatoes mixed anaerobic fermentation have longer gas production cycle,the gas production peak of that is concentrated in the latter part of the reaction,single anaerobic fermentation of potato was significantly inhibited by VFA,the cumulative gas production was significantly reduced.