Date of Award


Degree Name

Master of Science in Engineering


Mechanical and Aerospace Engineering

First Advisor

Dr. Bade Shrestha

Second Advisor

Dr. HoSung Lee

Third Advisor

Dr. Chris Cho


Biogas purification, portable, commercialization of biogas, condensation, gravity separation

Access Setting

Masters Thesis-Open Access


Biogas is produced from the decomposition of organic materials like manure, sewage sludge or crop fodders in anaerobic digesters. It consists mainly of 40 – 75 % of methane (CH4), 15 – 60 % of carbon dioxide (CO2) and trace amounts of other components. The principle constituents of biogas are similar to natural gas. Natural gas has 87 – 97 % of methane (CH4) and 0.1 – 1 % of carbon dioxide. Natural gas is known to be an alternative fuel with a wide range of applications. The commercial purification technologies exist for large-scale biogas units. However, there are no such commercial purification technologies available for small biogas units (farm scale or household). The aim of this project is to propose a commercial portable purification and storage system for small biogas units that can be handled by a single person. This portable technology will provide an opportunity to generate an extra income source to the deprived and poor biogas unit owners, who are often located in the very poor and deprived areas where even general transportations may not available.

This work has identified and designed the components required for the proposed portable purification and storage system and their components. The proposed system has two compressors, two heat exchangers, a liquid-gas separator and a storage tank, with a total portable weight of about 12 kg excluding the storage tank. The system is capable of purifying 15 kg of biogas per hour producing and storing 4 kg biomethane. The numerical simulation of each individual component to validate the proposed purification method are also presented and discussed.