(The Gist of Science Reporter) Methanol and DME Economy in India [FEBRUARY-2019]
(The Gist of Science Reporter) Methanol and DME Economy in India
Methanol and DME Economy in India
Globally, production and utilization of methanol have been on the rise
due to multiple drivers like availability of cheap raw material like coal
and natural gas: securing energy supplies among increasing oil prices;
strategic like reduction of oil import bills, and environmental concerns
about pollution and climate change.
Use of methanol as a fuel and chemical intermediate provides multiple
avenues for its utilisation with rapidly increasing demand for automobile
and consumer sectors. Methanol is an efficient fuel due to its high octane
number (~100) and emits lesser pollutants like SOx. NQx and Particulate
Matter (PM) as compared to gasoline.
Methanol-gasoline blends ranging from M15 to M85 have been adopted in
countries like China, and it has been established as a transportation fuel
along with other applications.
Methanol can be dehydrated to produce Dimethyl Ether (DME) which can
replace diesel and also can be blended with LPG. Other applications of
methanol include conversion to chemicals formaldehyde, acetic acid and
various olefins like ethylene and propylene.
The initiative by Niti Aayog towards the “Methanol Economy” promises to
help our nation in mitigating petroleum import costs and at the same time
counter problems associated with global warming due to excess CO2,
emissions. India imported 37% of its total primary energy demand in 2015-16,
whereas the import dependence of crude oil and natural gas has increased
from 73% and 17% in 2005-06 to 81% and 40% in 2015-16 respectively.
The current production process for biomethanol involves gasification of
biomass to generate syngas which can be converted to methanol using existing
catalyst and conversion technology. However, the technology requires
cleaning of gas generated and is viable at large scale.
Due to its relatively high cost biomethanol production is limited as
compared to standard methanol Also the challenge in logistic of biomass
collection provides the opportunity to develop novel approaches in smaller
scale and decentralised production processes that reduce the capital costs
of biomethanol plant and benefit the rural communities.
Biogas as Feedstock for Methanol Production
Anaerobic digestion of agro-residues and agro-industrial waste into
biogas provides a sustainable source of energy Biogas contains methane (CH4)
as the major component (50%
-70%) and is an emerging renewable feedstock for fuels and chemicals.
Currently, the total biogas production in India is around 2.07 billion
m’/year, Biogas produced by digestion of distillery spent wash, food waste,
Municipal Solid Waste (MSW), sugar and oil industries can serve as a major
feedstock for production of methanol.
The new biofuel policy of India has also put major thrust on the
development of Biogas/Bio-CNG plants across the country. According to the
estimates of oil marketing companies, approximately 100-120 million tonnes
of biogas (50- 60 million tonnes of Bio-CNG) can be produced from different
sources. This provides an investment opportunity of around 5000 biogas
plants with a capacity of 50 tonnes/day of biogas assuming 300 days of
Growth in biogas plants can support several applications including
methanol along with replacement of imported natural gas for existing
applications, Methane can be thermo-chemically converted to methanol using
syngas route, but the process requires expensive metal catalysts and
operates at high temperatures (200°C-900 °C) and pressures (5-20 MPa),
Thermo chemical technologies have a high capital expenditure due to large
size of plants and require a methane source that is free of impurities.
Moreover, existing technologies for methanol production are inefficient due
to multiple steps and by-product generation.
Biogas contains carbon dioxide (30%-50%) and trace impurities such as
hydrogen sulphide (0-2000 ppm) and purification processes to enrich methane
makes it an expensive feedstock for chemical conversion.
Biological conversion of biogas to methanol is an emerging, attractive
approach as it may not require biogas purification and uses ambient
conditions, reducing operational costs and energy Demands.
The interest in methanol production is the main driver for research into
novel process technologies. However, the current scale of production in the
natural gas based methanol plants increases the risks and challenges in the
introduction of renewable technology routes. The new biomass based
technologies may be better deployed in small-scale plants through savings in
feedstock supply chain and consumption in local markets.
Improvements in gasification technology can be applied to both renewable
and non-renewable sources of methanol. Conventional gasification such as
fixed bed, fluidized bed and entrained flow reactors have been proven for
commercial biomass to power applications and can be adapted to produce
biomethanol. However, high investment costs, low gas quality and poor
efficiencies have limited their application to liquid fuel production.
New developments in gasification technologies are focused on plasma
gasification along with exploration of improved process integration and
intensification for biomethanol production. Although these approaches are
technically feasible they are not yet economically attractive for biomass to
A fermentation-based technology for methanol production can be developed
using methanotrophic bacteria, which possess the ability to convert methane
to methanol using methane monooxygenase enzyme. The major advantage of a
fermentation-based technology lies in the direct conversion of methane to
methanol vis-a-vis indirect conversion by chemical catalysis route. Direct
biochemical conversion to biomethanol at ambient temperatures provides
several benefits like improvement in overall yield and selectivity of the
process. Fermentation based processes also have lesser operating cost and
can be economical at smaller scale as compared to a chemical process. From
environmental viewpoint, fermentation processes are cleaner as they generate
lesser effluent and greenhouse gases.
Ethanol production is the best example of a fermentation-based process
with wide-ranging capacity plants operating in a decentralised manner. A
sugar-ethanol distillery complex installed with a biomethanation system for
treating press mud and distillery spent wash can be retrofitted to produce
biomethanol from generated biogas, The other benefit of using methanotrophic
bacteria lies in its ability minimal media requiring to grow on lesser
process inputs. Methanotrophic organisms have better tolerance to impurities
like H2S and do not require the cleaning of biogas as in the case of a
chemical catalyst. Some of the methanotrophs are reported to utilize CO2, a
characteristic that can be further exploited in the biogas to methanol
R&D of Biomethanol Production National Status In India, agro-residues
and agro-industrial wastes form a major source of bio-resource having the
potential for bioenergy. Anaerobically converting them to biogas provides a
sustainable energy source as well as simultaneous route to nutrient
recycling (nutrient-rich compost) to soil. Some studies have been done on
the bioremediation potential of Trichloroethylene (TCE) using methanotrophic
organisms. Negligible reports are available on the development of wild type
or genetically engineered organisms for conversion of methane to methanol.
Also synergistic research areas like development of advanced gas
fermentation system for increasing gas to liquid mass transfer rates and
life cycle analysis studies of biogas to methanol conversion are lagging in
comparison to global status.
R&D of Biomethanol Production International Status
At the global level, both chemical and biotechnological routes of direct
methane to methanol conversion are under development. For direct methane to
methanol conversion using chemical catalysis, several approaches like
catalytic gas phase oxidation, catalytic liquid phase oxidation and
mono-halogenated methane have been studied. These approaches had challenges
like low conversion yields and expensive catalyst. Globally, no direct
conversion based plants have been built till date.
The development of MMOs as standalone biocatalysts for methane to
methanol bioconversion has been hindered by their structural complexity and
requirement for regeneration of reducing power for the biocatalytic
A polymeric hydrogel material immobilizing the membrane-bound pMMO has
been developed which was embedded in a silicone lattice to construct a
flow-through bioreactor for production of methanol up to 600 nmol/mg enzyme.
Genome scale metabolic reconstruction models have been studied in
Methylosinus trichosporium. Methylomicrobium buryatense and Methylomicrobium
alcaliphilum. The model for M. buryatense 5G(B1) strain incorporated 841
reactions using whole genome predictions and expression data. Such models
can be applied to study and predict metabolic parameters for nutrient and
genetic variations to devise strategies for enhanced methanol accumulation
and engineer cofactor regeneration. R&D Interventions to Bridge
In order to develop a commercially viable fermentation process for
methanol production, more research is required in the area of bioreactor
design to improve gas to liquid mass transfer rates. Gas-based fermentation
is fundamentally different and more challenging from ‘traditional’ glucose
based fermentation for several reasons including the low solubility of
methane in aqueous solution; the need to feed multiple gases at high mass
transfer rates; and significant heat loads generated from the metabolism of
the high-energy methane substrate.
Significant improvements in the methanotrophic strains would be required
to further improve the yield, titer and productivity of methanol. An
integrated approach based on modern techniques of genetic engineering,
enzyme engineering, reactor design and computational fluid dynamics tools
would be useful in designing an efficient biocatalyst and a robust
bioprocess for biogas to methanol conversion. Toxicity of methanol is one of
the major limiting factors in increasing methanol accumulation by
methanotrophic strains. To improve the tolerance of methanotrophs to
methanol directed evolution strategies like serial adaptation or chemostat
cultivations be employed. Directed evolution strategies can also be applied
for overcoming inhibitions from impurities like Hydrogen sulphide present in
Biomass/MSW based biogas plants can create a viable alternative for
methanol production in India which will be competitive at the global scale.
Addition of methanol production unit will result in significant value
addition to the. Biogas plants resulting in higher revenue for the biogas.
As compared to current applications of biogas like steam and power
generation, or enrichment to BioCNG, Biogas to Biomethanol conversion can
provide maximum returns per unit of biogas produced.
Development of indigenous technologies will create a viable alternative
for methanol production in India which will be competitive at the global
scale. The biomethanol production will result in significant value addition
to the biogas plants resulting in higher revenue for the biogas as well as
the construction of several decentralised small plants across the nation.
Biomass-based biogas plants will help in the creation of rural jobs and
additional income for fanners. Several small and medium scale industries
will be benefitted by the commercialization of biomethanol technology and
will help in improving the rural and national economy.