Improving The Removal Efficiency of Carbon Dioxide and Hydrogen Sulfide from Biogas Using Different Stirring Methods for Chemical Solutions Used in The Purification Process تحسين کفاءة عملية الإزالة لغاز ثاني أکسيد الکربون وکبريتيد الهيدروجين من الغاز الحيوي باستخدام طرق التقليب المختلفة للمحاليل الکيميائية المستخدمة في عملية التنقية.

Abstract

The main purpose of this study was to improve the biogas quality by keeping the methane content above 90%. To achieve this goal, it has been used a combined stage of slaked lime solution 50%and sodium hydroxide of 10 and 20% respectively at different stirring methods. The stirring methods were; without stirring, manual stirring, and mechanical stirring at speeds of 250, 200 and 150 rpm.The obtained results indicated that, a combined stage of slaked lime solution 50% and sodium hydroxide of 10%and 20%respectively with mechanical stirring at speed of 150 rpm showed a highly removal performance compared with the other different treatments. The methane content was above 99% through the first 32 hours compared with 19, 28 and 29 hours for manual stirring and mechanical stirring speeds of 250 and 200 rpm respectively. Moreover, the methane content was remained above 90% at removal time of 44 hours compared with 32, 40 and 41 hours for manual stirring and mechanical stirring at the same speeds respectively. In addition, the mechanical stirring at speed of 150 rpm gave the highest average removal efficiency of carbon dioxide 95.9% which keeping it less than 10% compared with 92.1, 94.6 and 94.7% for manual stirring and mechanical stirring at speeds of 250 and 200 rpm respectively. On the other hand, the highest average removal efficiency of hydrogen sulfide during purification process period off 44 hours was 79.2% compared with 78.5 and 78.9% for the two other mechanical stirring speeds of 250 and 200 rpm respectively.