Why producing CBG, LBG, hydrogen, methanol from biogas can be beneficial?

Published
20th Oct, 2022

Context

It has been observed that due to the unavailability of biogas in bulk, absence of infrastructure to generate & market these fuels main hurdles. So, there is a need to enhance the renewable energy sector via product transformation like CBG, LBG, hydrogen and Methanol using Biogas.

About

What is Bio-gas?

It mainly comprises hydro-carbon which is combustible and can produce heat and energy when burnt.
Biogas is produced through a biochemical process in which certain types of bacteria convert the biological wastes into useful bio-gas.
Since the useful gas originates from a biological process, it has been termed as bio-gas.
It is primarily composed of methane (50-65 per cent), carbon dioxide (30-40 per cent), hydrogen sulphide (1-2.5 per cent) and a very small fraction of moisture.

How it is produced?

Biogas is produced when bacteria digest organic matter (biomass) in the absence of oxygen. This process is called anaerobic digestion.
It occurs naturally anywhere from the within the digestive system to the depth of effluent ponds and can be reproduced artificially in engineered containers called digesters.

Method of Purification:

The removal of unwanted components like carbon dioxide, hydrogen sulphide and moisture from raw biogas yields pure methane (over 97 per cent content).
Some of the common methods to purify biogas include;
- water scrubbing,
- membrane separation,
- pressure swing adsorption and
- Adsorption.

Other related products:

Biogas Products

features

1. Compressed Biogas (CBG)

2. Liquefied Biogas (LBG)

3. Bio-Methane

4. Hydrogen produced by Bio-gas

The upgraded or high-purity biogas compressed at 250 bar pressure results in a fuel called compressed biogas (CBG).
Uses: This has properties similar to compressed natural gas (CNG) and could be directly used to power CNG engines.

If the biogas-derived methane is liquefied by cooling it at -162 degrees Celsius, the fuel thus obtained is liquefied biogas (LBG).
It has a higher energy density that lowers storage space requirements.
Uses: LBG has become a viable alternative fuel for heavy-duty road transportation since it has a comparatively high energy density (1 litre of LBG against 2.4 litres of CBG), low sulphur content and lower life cycle greenhouse gas emissions than diesel.

Bio-methane can also be transformed into other fuels such as hydrogen and methanol.

The primary method for producing hydrogen encourages the reforming of light hydrocarbons, particularly methane, which makes up a significant portion of biogas.
Gasification is performed by limiting the amount of oxygen and steam present in the reaction and heating the bio-methane to high temperatures (usually over 600°C).

Syngas, a mixture of hydrogen and carbon monoxide, is created as a result of this process.

The hydrogen produced after the removal of carbon monoxide could be used in fuel cells to generate power.

Government Initiatives

SATAT Scheme: CBG is the only transportation fuel from biogas for which commercialisation efforts have been made.
The Indian government has been encouraging private businesses to set up CBG plants and provide CBG to oil marketing companies for sale as automotive and industrial fuels under the Sustainable Alternative towards Affordable Transportation (SATAT) scheme launched in 2018.

Future goals:

Currently, LBG, hydrogen and methanol are not produced from biogas in India.
The main reasons are the unavailability of biogas in bulk for such derivatives, the absence of infrastructure to generate and market these fuels, the deficiency of modified automobile engines as well as the lack of effective research and development push to improve process economics.
The Indian government and Niti Aayog have outlined roadmaps to hasten our transition towards green fuels and promote LBG, hydrogen and methanol.