Bio Gas To CNG


VPSA system has different stages to perform for purification of the Bio gas. Firstly, Bio gas stored in the gas holder goes through Suction process by Blower and pressurized. The pressurized Biogas passes through water Scrubber. In this process, water is used as an absorbent to remove partially H2S and ammonia.

The water is supplied from the top of the column while the raw biogas is allowed to pass from the bottom to top. Ammonia and H2S trapped in the water and CH4 with CO2 and some traces of other gases along with moisture leave at the top of the water scrubber. After water scrubbing the gas passes through Chemical Scrubber where further H2S is trapped in iron flakes.

After Chemical Scrubber process, the gas is made to pass through customized Biogas Dehumidifier where gas is cooled down to 8-10 Deg C and moisture is condensed and removed in cyclonic moisture separator which is automatically discharged through auto drain valve.

Now the outgoing low temperature gas is passed through economizer / reheater to reduce the inlet Biogas temperature to reduce load on chiller and also outgoing gaows is heated up to 30 Deg C for enhancing the RH of the Dehumidified gas so that no further condensation takes place due to expansion in Adsorber Towers. Next,

we are using Activated Carbon Filter to remove impurities like H2S, VOC & Siloxane etc., For further purification of Bio Gas, we use VPSA technology. This method is particularly used to remove CO2 present in cleaned and dehumidified biogas. The dry biogas (after moisture removal) enters at the bottom of the adsorption column filled with different grades of molecular Sieves,

Activated Alumina/Silica Gel where CO2 is adsorbed and pure dry methane leaves from the top of the towers which is sent to a surge vessel for analysis. When one tower is in Adsorption process the other adsorber tower undergoes in Regeneration by depressurization process and vacuum with the help of a vacuum pump.

The exhaust gas mainly containing CO2 is released into the atmosphere at elevated height. After a preset timing the process is changed from one tower to another to keep producing the pure gas continuously. It is done through automatic changeover valves signaled through a PLC. Stored pure gas in surge vessel is analyzed for purity and sent to the final storage if minimum methane percentage is achieved.


     M/s MAAS AIR-N-GAS TECHNOLOGIES PVT. LTD., are pioneers in PSA/VPSA based gas separation technology manufacturing Biogas Purification Plants, N2 and O2 generation plants, Custom designed Biogas & Air Dehumidifiers, Industrial Dryer and filters since 2007 having its Corporate Office and Manufacturing units in Ahmedabad. M/s. MAAS AIR-N-GAS TECHNOLOGIES PVT. LTD., is an ISO 9001 certified fully integrated engineering company having accreditations from TUV NORD, TUV SUD, Bureau Veritas and worked with consultants like SAIPEM. With more than 500 satisfied customers pan India and abroad which includes NTPC, ISRO, ONGC, RELIANCE, ADANI, PIRAMAL GROUP, ZYDUS ETC, M/s. MAAS AIR-N-GAS TECHNOLOGIES PVT. LTD., has carved its name among the top few in this technology. The CEO of M/s MAAS AIR-N-GAS TECHNOLOGIES PVT. LTD., Mr. Shailesh Verma has a rich hands-on experience of 30+ years in this technology, having worked with companies like INDCON and thereafter running his own manufacturing unit since 2007.

     In 2012, M/s. MAAS AIR-N-GAS TECHNOLOGIES PVT. LTD., entered into a research agreement with SARDAR PATEL RENEWABLE ENERGY RESEARCH INSTITUTE (SPRERI) at Ananad – Gujarat thru which the institute agreed to jointly develop commercially scalable PSA/VPSA technology in the field of renewable energy and more particularly into CNG equivalent gas from Biogas using PSA/VPSA technology. Having jointly conducted various experiments for 5 years on upgradation of Methane using different adsorbent under Indian Conditions more specifically the pre-treatment of Biogas required for consistent purity of Methane and longer life of Molecular Sieve, we entered this market of BIOgas purification with in-depth knowledge and elaborate data on different composition of Biogas and use of VPSA/PSA method for its purification.


  1. Proficient 4 stage pretreatment process for removal of contaminants like H2S, VOCs and Moisture etc…
  2. Complete Pretreatment System in SS 304, ensuring long life of the plant.
  3. Moisture removal up to -60 Degree ADP ensured thru custom designed fully SS low pressure zero loss dehumidifier.
  4. Only world renowned and recognized CECA (Arkema) Molecular Sieves are used in PSA towers.
  5. Proprietary, scientifically designed purge loss recovery system to ensure negligible losses of Methane.
  6. Man Less Operations thru PLC with HMI. Provision for remote access to process control.
  7. Clean Process with high Performance, stable and user-friendly operations.
  8. Well researched design to ensure long life and trouble-free operations of the Plant