Biogas purification system

About Biogas purification system

Biogas is comprised of Methane (CH4, about 45-75% by volume), Carbon Dioxide (CO2, 25-55%), and other compounds including Hydrogen Sulphide (H₂S, present in concentrations from several hundred to a couple of thousand parts per million), water, and other trace gas compounds. Methane, if extracted from the biogas would be used as replacement of CNG or LPG.

Various methods are available for Methane extraction from the biogas are water scrubbing, chemical absorption, Membrane separation, Bio-filter, cryogenic separation and Pressure swing absorption.

Each method has its own advantages and disadvantages. Most of the purification systems are capital intensive and attract very high cost. Further, operating such systems at larger scale is very much viable but, high capital and operational cost makes it unfeasible for smaller projects.

Hence, in order to address this problem and to provide viable gas purification solution for smaller plants, we alongwith IIT Bombay have designed a water based biogas purification system.

In this system biogas is passed through the innovative rotating contacting disk-based biogas purification system - designed and developed by IIT Bombay. The system has several advantages like low energy consumption, near to zero pressure drop, easy to operate, low capital and operating cost.

The purification system removes the CO2 and other impurities and delivers the cleaner gas.

The system consist of a water reservoir or a tray of adequate capacity. The stored water is pumped to the rotating drums. The flow of water rotates the drums. The gas is passed through the rotating drums. When gas comes in contact with water, the CO2 is absorbed in the water and pure methane is obtained from the outlet. The absorbed CO2 is released into air while passing water through the strippers.