Design, a Study of Laboratory-scale Experimentation and Economic Analysis of Biogas Plant for Phuentsholing Area

Abstract

The project focuses on designing the biogas plant considering the normal temperature of Phuentsholing area and carrying out the laboratory experiment for the different feedstock. Factors like temperature (ambient temperature), pH value of leachate, pressure, and the ratio of the feedstock to water has been considered. The paper also presents the amount of gas produced by the different feedstock. The three different feedstocks used are rice water, brewery waste, and the cow dung. The total solid suspended (TSS) test for each feedstock was performed to ensure the minimum content of 20,000 mg/l. For hydraulic retention time (HRT) of 10 and 21 days, the readings were recorded from the laboratory scale experimental setup. For measurement of the gas volume, the U-tube manometer is used. The volumes of gas produced per kg are 0.1411 cm3 /kg, 0.0641 cm3 /kg, and 0.1026 cm3 /kg for cow dung, brewery waste, and rice water respectively in 10 days. Besides, the result of the experiment, the volume of gas produced is integrated for real-time quantities of the feedstock. Based upon the result of the experiment, the design of the plant was made, whereby the digester volume is calculated theoretically, and the cost involved in building the plant is also estimated. The energy content of biogas produced is also calculated and compared with two other energy sources, which are electricity and liquified petroleum gas (LPG).