Anaerobic Fermentation Characteristics Research Of Wheat And Rice In Different Organs And Heights

Straw was the solid residue after harvesting the crops,including crop stalks,leaves.The wheat also includes meet shell and mans,etc.Agricultural straw yield is more than 700 million tons per year in China,including rice and wheat straw accounted for nearly 50%which is the main source of agricultural straw.The main components f agricultural straw is lignocellulose.It's utilization technology includes composting,feed,industrial raw materials,binders,etc.In recent years,with the shortage of clean energy in rural areas and the processing of straw has become increasingly prominent,the use of straw biogas at the same time solve the above two problems,and is one of the most important ways of straw recycle.Current research of straw biogas utilization exists a lot,but mostly focused on the pretreatment of raw materials,fermentation process optimization,etc.The research on gas potential of different organs of straw,physical and chemical properties,gas characteristics in different heights of the ground straw residue has not been reported.It is important to guide the straw collection way,such as stubble height,straw collection area,etc.As the straw technology progress of collection,crushing and grinding and separation,straw can be divided into different parts.To give full play to different organs of straw utilization potential,based on rice and wheat straw as raw material,The physical and chemical properties,and anaerobic fermentation gas production of the rice and wheat straw was studied in different organs and different height above ground.The research contents and conclusions of this thesis were as follows:According to ear shell,mans,stems,leaves,and according to the different height of the 0 to 10 cm,10-20 cm,20-30 cm,>30 cm,three different varieties of wheat and rice are divided into different parts.Then their TS,VS,C,N,organic matter,the cold water and hot water extract content,three contents(Hemicellulose,cellulose and lignin)are determined.The results of three different varieties of wheat to produce methane potential were as follows:the leaf of Xu 30 is the maximum gas potential of different tissues organs.TS gas production rate is 341.2 mL/g.The average methane content is 53.89%.Different height of straw exist different gas potential.The gas potential of>30 cm height is the best site;TSgas production rate is 311.45 mL/g and the average methane percentage is 58.06%.In Xu33,stems is the maximum gas potential part of different organs;TS gas production rate is 386.63 mL/g;the average methane percentage is 52.1%.The best gas potential part of the different height is about 20 to 30 cm;TS gas production rate is 327.6 mL/g and the average methane percentage is 54.38%.In Bao1082,stems is the maximum gas potential part of different organs;TS gas production rate is 364.25 mL/g and the average methane percentage is 56.03%The best gas potential part of the different height is about 10-20 cm height;TS gas production rate is 334.58 mL/g and the average methane percentage is 57.37%.For the biggest gas potential of different organs,difference of three wheat is not too big.The stalks of Xu33 is 13.31%higher than the leaf of Xu30,and is 6.14%higher than it of Bao1082.Referred to the straw gas potential maximum of different height,differences between three different varieties of wheat is not obvious.The results of three different varieties of rice to produce methane potential were as follows:According to the organs of rice straw,the stem has always been the greatest potential to produce gas.The TS gas production of NANJING44,NANJING45 and YANG6 rice,respectively,is 325.8mL/g,322.7mL/g,345.9mL/g;The average methane fraction is 62.6%,63.2%,62.5%.Straw divided according to different height,the part with the biggest potential of NANJING44 is above 30 cm.TS gas production is 322.1 mL/g;The average methane fraction is 54.9%.The part with the biggest potential of NANJING45 is from 10cm to 20 cm.TS gas production is 268.2mL/g,and average methane fraction is 60.76%.The part with the biggest potential of YANG6 is on 20-30cm.TS gas production is 319.5mL/g,and average methane fraction is 61.74%.In the varieties of rice,the difference between stem and leaf gas production is obvious.The gas potential of different height straw exists significant difference.The difference of the stalk gas potential in different varieties of rice is not obvious.The biggest gas potential of rice stem and leaf organs is lower than that of wheat.Different tissues and organs of straw gas potential is related to its chemical composition,Founded that the largest gas potential parts corresponds to the higher organic matter content,three contents also satisfy at least one condition:Cellulose content is the highest or higher,hemicellulose content is the highest or higher,lignin content is the lowest or lower.