Optimum Design Of A Solar Biogas Project And Research On The Effect Of Raising Temperature

There is little gas production from the biogas projects because of the low air temperature in north area,and it need to increased fermented liquid temperature to rely on fuel and renewable energy consumption.Based on this existing condition,biogas projects toward to the direction of less investment, increased fermentation temperature by using renewable energy, management simple, low operating costs, high gas production rate, gas production stability, have gas production in winter, non secondary pollution, save the land resources, use for long years. In this paper,we optimal design and build a small solar biogas projects .And study on the effect of it’s raise the fermenting liquid temperature through solar hot-water facilities,solar greenhouse and solar-sweltering pools—use solar by triple effects. The result of research is as follows:(1)In winter,the fermenting liquid average temperature for the treatment of solar hot-water facilities and solar greenhouse is 13.21℃.It’s 2.23℃higher than the treatment of solar greenhouse,3.56℃higher than comparison.And its gas production could reach 16.16 m3/d,77.58% more than comparison,the gas production of only using greenhouse is 12.14m3/d,33.14% more than comparison;In summer,the fermenting liquid average temperature for the treatment of solar hot-water facilities and solar greenhouse is the highest,up to 29.63℃.It’s 3.30℃higher than the treatment of solar greenhouse,4.78℃higher than comparison.And gas production is 39.24m3/d, 46.69% higher than comparison,the gas production of only using greenhouse is 32.32m3/d,20.82% higher than comparison; Therefore,the effects of raising temperature and gas production of solar hot-water facilities and solar greenhouse is best the other treatments,The comparison is the worst.(2)During the trials, the fermenting liquid average temperature in solar-sweltering pools is higher than the temperature in the solar greenhouse,and less affected by the atmospheric temperature,temperature fluctuations also relatively small.In winter, average temperature of the fermenting liquid in solar-sweltering pools is 18.40℃,the average temperature topped 21.90℃, the lowest 15.20℃;In summer, the average temperature is 45.13℃,the haightest was 48.10℃,the lowest was 41.80℃.If we raised the fermenting liquid from the biogas projects into the solar-sweltering pools for raise temperature cycles ,that the liquid can anaerobic fermentation at ambient temperature, ensure the gas production in winter ;But in summer,the fermenting liquid can be raise to 34.24℃,anaerobic fermentation at normal temperature,which greatly improved the raw material utilization and the gas yield.(3)Having been influenced by solar radiation intensity,the every effects of it raise the fermenting liquid temperature is better in summer than in winter were significant at 0.01 level,and the effect is better on an additional effect,it is have a high utilization ratio of solar through use solar by triple effects which well proved the heating system design rationality and high efficiency.