"BIOGAS" , When we listen this word what comes first in our mind? It is a GAS which is made by the biological products, and its true.
Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen.
Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste.
So, we can produce BIOGAS easily by the waste products which are available in our nearby.
Biogas is used as transportation fuel in a number of
countries, but in Europe it has only reached a major breakthrough
in Sweden. All of the biogas plants in Sweden that
are in the planning or construction phase will be equipped
with possibilities to deliver a biogas that is upgraded to
natural gas quality, either for direct use as vehicle fuel or
for injection into the natural gas grid.
The development of biogas as vehicle fuel in Sweden is
a result of a combination of a surplus of gas from biogas
plants, primarily at the sewage treatment plants, and a low
electricity price that forces the biogas into markets other
than electricity production.
SOURCES OF BIOGAS
Sewage treatment plants: Many sewage treatment plants
produce methane rich gases in the sludge fermentation
stage. Utilisation of methane from sewage plants is used
on a large scale in many countries. Optimised process
conditions can enhance the production and collection
of these gases.
Cleaning of organic industrial waste streams: Anaerobic
digestion processes are often successfully applied to clean
the waste streams of agricultural processing industry,The methane rich gases are mainly utilised to produce
electricity and heat in local co-generation plants.
Landfills: All landfills produce methane rich gases.
Collection and utilisation of the gases is applied quite
widely. Improved collection, processing and utilisation
of landfill gases will be an important tool to increase
the importance of landfill gas.
Mesophilic and thermophilic digestion of organic waste:
Compact installations convert organic waste to methane
rich gases at higher temperatures. The main difference
between the two methods is the digestion temperature
(35°C in the mesophilic process and 55°C in the ther
mophilic process).
Composition of BIOGAS
- Methane -60-65%
- Carbon dioxide - 35-40%
- Hydrogen sulphide - 0.5-1.0%
Properties of biogas
- Biogas is non-toxic, color less and flammable gas.
- It has an ignition
temperature of 650 - 7500C.
- Its density is 1.214kg/ m3
(assuming about 60% Methane and 40%
CO2).
- Its calorific value is 20 MJ/m3
(or 4700 kcal.).
- It is almost 20% lighter than air.
Upgrading of biogas to natural
gas quality
Biogas has to be upgraded to natural gas quality in order
to be used in normal vehicles designed to use natural gas.
The most common technologies are the water scrubber
technology and the PSA-technology. Gas upgrading is
normally performed in two steps where the main step
is the process that removes the CO2 from the gas. Minor
contaminants are normally removed before the CO2-
removal and the water dew point can be adjusted before
or after the upgrading (depending on the process).
Biogas vehicles
Biogas can be used in both heavy duty and light duty vehicles.
Light duty vehicles can normally run both on natural
gas and biogas without any modifications, whereas heavy
duty vehicles without closed loop control may have to be
adjusted, if they run alternately on biogas and natural gas.
Sweden is the only country in the world with a national
standard for biogas as vehicle fuel today. This standard
essentially states that the methane content must be higher
than 95% and also sets limits for dew point, sulphur content
and some other minor constituents.
Today there are more than 4.000 vehicles in Sweden
running on natural gas and biogas and several local fleets
(e.g. Linköping, Uppsala, Kristianstad) where the major
part of the urban public transports are operated on biogas.
Scope of BIOGAS in India
India is implementing one of the World’s largest programme in renewable energy. The country
ranks second in biogas utilization. Biogas can be generated and supplied round the clock in contrast to
solar and wind, which are intermittent in nature. Biogas plants provide three-in-one solution of gaseous
fuel generation, organic manure production and wet biomass waste disposal/management.
Technology Demonstration on Biogas Bottling under RDD&D
First time in the country during the year 2008-09, a new initiative was taken for technology
demonstration on biogas bottling projects in entrepreneurial mode, for installation of medium size mixed
feed biogas plants for generation, purification and bottling of biogas under RDD&D policy of MNRE
after R&D. Installation of such plants aims at production of CNG quality of Compressed Biogas (CBG)
to be used as vehicular fuel in addition to meeting stationary & motive power, electricity generation,
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thermal application etc. needs in a decentralized manner through establishment of a sustainable business
model in this sector. There is a huge potential for installation of such plants in various areas. Under the
demonstration phase, the Ministry has sanctioned a central financial assistance for a limited number of
such projects for implementation following an entrepreneurial mode in different states namely
Chhattisgarh, Gujarat, Haryana, Karnataka, Maharashtra, Punjab, Madhya Pradesh, Andhra Pradesh and
Rajasthan.
So far, 11 numbers of biogas bottling projects of various capacities and technologies have been
commissioned in the country after obtaining required licenses for filling and storage of compressed
biogas in CNG cylinders from Petroleum & Explosives Safety Organization (PESO), State Pollution
Control Board (PCB) etc.
IIT, Delhi is assigned for technical monitoring & handholding of the consultants/promoters and
preparation of documentation on different types of technology which may emerge out of these projects.
Thanks for reading.
