A comparison of CBG (Compressed Bio Gas) and CNG

Why in News?
Verbio AG, a German company is setting up compressed biogas(CBG) plant in  Bhutal Kalan village in Punjab. Increasing CBG production is much more beneficial compared to the Production of CNG.

Facts:

• Compressed Biogas(CBG): It is a purified form of biogas. It can be produced from waste including municipal solid waste, sludge from wastewater treatment plants, market residues, agricultural residues, cattle dung, sugarcane press mud among others.

Process of Producing CBG: CBG from biomass involves a two-pronged approach.

1. First Step: Biogas is produced through the anaerobic decomposition of biomass.
   • Anaerobic Process: In this process, microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels.
2. Second Step: Biogas contains 55 to 60% methane, 40 to 45% carbon dioxide (CO2) and trace amounts of hydrogen sulphide. The second process involves purifying the gas to remove carbon dioxide and hydrogen sulphide gases to prepare CBG.

How is CBG different from Compressed Natural Gas(CNG)?

1. Chemically, CBG is the same as CNG — both are compressed methane — and have the same calorific value.
2. But, CNG is a by-product of petroleum, and CBG can be produced from any biomass, be it crop residue, cattle dung, sugarcane press mud, municipal wet waste, or effluents from a sewage treatment plant.
3. Hence, this makes CBG a commercially viable option as it can be directly used to replace CNG in transportation fuel. Just like CNG, CBG too can be transported through cylinders or pipelines to retail outlets.

Other advantages of CBG:

1. Compressed biogas has the potential to minimize India’s need to import fuel.
2. The solid by-products of CBG can be used as bio-manure. According to experts, bio-manure produced using paddy straw can result in a 20% increase in crop yield.
3. The other by-product from CBG is CO2. It is used to produce a liquid or solid CO2. It has a high demand for food preservation or to be used in fire extinguishers.

Government Initiative to promote CBG:

1. Sustainable Alternative to Affordable Transport(SATAT) Initiative: It was launched in October 2018 to promote the Compressed Biogas (CBG)
2. The scheme targeted the production of 15 million metric tonnes (MMT) of CBG by 2023.
3. Public sector undertakings oil marketing companies(OMCs) including IOCL partnered with potential entrepreneurs under this initiative to set up plants and supply CBG to them for sale as automotive and industrial fuels.

Source: Down To Earth