SELECTIVE ADSORPTION-BASED MULTI-STAGE DRY PURIFICATION SYSTEM FOR BIOMETHANA PRODUCTION FROM BIOGAS

Abstract

The present invention relates to a multistage dry purification system that uses a selective adsorption process to improve the quality of biogas to high-quality biomethane. The system comprises a pre-filter unit (1), a condenser unit (2), a water trap unit (3), a stage 1 adsorber unit (4), a stage 2 adsorber unit (5), an accumulator tank (6), a biomethane collection tank (8), a safety tank (9), and a user distribution tank (10), equipped with valves to distribute biomethane to end users in a safe and controlled manner. The purification method begins with fine particle filtration using a screen filter, followed by cooling in a shell-and-tube condenser without the use of a refrigerant, which reduces the gas temperature from 35–40 °C to below 25 °C and condenses water vapor into the water trap. The dry biogas is then passed to two adsorbent units containing 25 kg of activated carbon to remove H₂S and NH₂.The pure gas was temporarily stored in an accumulator tank before being automatically compressed into a storage tank pressurized at 10 bar. The results showed an efficiency in removing Hâ‚‚O of 97.95%, Hâ‚‚S of 99.99%, and NH₃ of 94.96%, as well as an increase in CHâ‚„ content from 38.2% to 84.12%.