Two-Phase High-Temperature Anaerobic Digestion Experiment of Crop Straw

Abstract

: With the rapid development of agriculture, the output of crop straw has also increased year by year. The treatment and development and utilization of crop straw have become the focus of attention from all walks of life. In order to improve the utilization rate of crop stalks, save energy and protect the environment, this article conducted an in-depth study on the two-phase high-temperature anaerobic digestion test of crop stalks. First, the response surface method is used to control the organic loading ratio and the inoculation ratio respectively, and analyze the daily methane production and daily cumulative production. The test results showed that the A5 group on the 5th day (the organic loading ratio was 20gVS/L) had the highest single-day and cumulative methane production, which were 6.15mL/gVS and 19.57mL/gVS, respectively. When the inoculation ratio was 0.4 on the 25th day, the B1 group had the highest methane production, which was 2.88 mL/gVS. Then, the rice straw was treated by ammoniating treatment and multi-strain cooperative treatment to analyze the differences in pH value, ammonia nitrogen content and lignocellulose degradation rate. The test data showed that the pH values of the two groups were between 7 and 8. The ammonia nitrogen content of the ammoniated treatment reached 4485.1mg/L, and the degradation rates of lignocellulose on the 35th day of the ammoniated treatment and the multi-strain co-treatment were 24.14% and 35.33%, respectively. This shows that the effect of multi-strains synergistic treatment is better than ammoniated treatment, with lower ammonia nitrogen content and higher lignocellulose degradation rate. Finally, under the same experimental conditions, two-phase high-temperature anaerobic digestion experiments were carried out using rice straw and corn straw, respectively, to analyze the differences in pH, ammonia nitrogen content and lignocellulose degradation rate. The pH values of the rice straw and corn straw reactors were 7.56 and 8.21, the ammonia nitrogen content was 984.2 and 1128.6 mg/L, respectively, and the lignocellulose degradation rate was 34.54% and 25.38%, respectively. This shows that under the same reaction conditions, rice straw is better than corn straw, has lower ammonia nitrogen content and higher lignocellulose degradation rate, and its gas production and utilization are higher.