Design And Experimental Study Of Household Biogas Fermentation System With Solar Heating

In cold regions of northwest china,because of the low air temperature and the low ground temperature,there are many problems about producing methane.For example,the rates of producing and using methane are low,even the digester fermenting is freezed.In reaction to the phenomenon,in conjunction with the features that Northwest China is rich areas in solar energy,we design a new solar biogas fermentation system which integrating the solar energy collector system and the anaerobic fermentation device.This device can produce methane with solar heating in winter of northwest China.The biogas yield could meet the demand of the peasant family's.The research contents and achievements as follow:1.Design of a complete set of solar biogas fermentation device.It contents a solar energy collector system and a anaerobic fermentation device.First of all, according to the needs of farmers for biogas digesters to determine the volume,and then we can have the shape of methane fermentation to optimize device design. According to the mechanical properties of and prices to determine the suitable fermentation device and the thickness of material.We needs additional insulation layer on the external of the fermentation device to reduce the heat loss of the external surface.Through the heat balance analysis of the fermentation devices,calculated the solar collector areas and the size of storage tanks that in the local real winter weather conditions to ensure the device running stably.2.Placed the device under the environmental conditions of winter to test. Monitoring the changes in the pH value of the fermentative liquid,the changes in gas production,and the temperature changes of various parts of the system.Though monitor the pH and the gas production dates we can determine the stability of the fermentation process and the gas production performance of the fermentation device. Through the temperature dates can heat up the sets of characteristics and insulation characteristics of the fermentation device.The experimental results show that the set of devices with good heating and thermal insulation effect.3.Using the method of dynamic economic to appraise the entire system。The results showed that the four evaluation indices,include the net present value,benefit, the internal returns ratio and the investment Recovery period are in line with the requirements.The promotion of this set of devices can generate good value for money, with good good prospect of application and extension.4.Through the ecological and social benefits analysis that the Solar household biogas fermentation system with solar heating,the promotion and the use of devices with better ecological and social benefits.The review on the study of attribution theory can help learn the development of the study,which can promote the study in this field.Achievements have been made on the study of this subject,but still with certain flaws.Through the Further Study, enhance the performance of various aspects of the system,and then,to promote it in rural area,it can improve the proportion of Renewable energy sources in China's energy structure.