Design And Small Size Biogas Engineering Economic Evaluation Of The Fermentation Reactor On Biogas From The Chopped Straw

In order to match the operating conditions of the traditional biogas fermentation equipment,the straw,as a biogas fermentation material,usually needs to be comminuted and pretreated during the engineering operation,and the operation is complicated and the biogas production is not continuous and stable at the same time.According to the present situation of agricultural mechanization in China,a biogas fermentation device suitable for mechanized harvesting of chopped straw?with 30⁵0 mm of particle size?was designed and studied in order to reduce the complex pretreatment procedure of raw materials.The optimum reflux ratio and fermentation load of the plant are studied in order to realize the simple operation of the segmental straw in the biogas fermentation plant,to continuously stabilize the gas production.Finally,the economic benefits of the certain scale engineering in construction and operation process are evaluated.This study provides some basis for the construction and development of straw biogas engineering.The main results are as follows:?1?Chopped straw for anaerobic digestion can reduce the time and energy consumption of pre-treatment process.The porous sieve plate fixed the chopped straw in the reactor to prevent the straw from floating and crusting.And the reactor run with liquid reflux stirring.The batch fermentation experiment was carried out with the small scale test device.Compared with the anaerobic digestion reactor with height to diameter?H/D?of1:1,the biogas production of the reactor with H/D of 3:1 is increased by 12.5%.The fermentation reactor on biogas from the chopped straw designed 3:1 of H/D as a result of the actual construction of the project and the effect of H/D ratio on biogas production are taken into account.?2?Designing the anaerobic digestion reactor with H/D 3:1 for continuous feeding and discharging test.the fermentation load is 60 g/L?TS?and the fermentation period of straw is 20 d,and under the condition of 5 d import and export,the experiment continuous operate about 90 d.The biogas production and the concentration of CH₄ are stable,it indicated that The fermentation reactor on biogas from the chopped straw can long-time and stable operation.And when the daily reflux ratio?reflux slurry to the device volume ratio?is 3:10,there has the best biogas production effect.?3?Based on the design and operation parameters of the fermentation reactor on biogas from the chopped straw.The economic was evaluated to the 100 m³ small size biogas project of crop straw.From the project net present value of finance,financial benefit-cost ratio,internal rate of return and the investment recovery period,the fermentation reactor on biogas from the chopped straw used in project construction and operation has economic feasibility.