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INDIAN SCENARIO

4.3 Processing of Different Feedstocks Simultaneously

Presently, the largest syngas producer in India is the fertilizer industry. The breakup of the
feedstock is approximately 56:26:12:6 for natural gas: naphtha: Fuel oil: coal or Residue
[58]. Most of the technologies deployed by the majority of fertilizer manufacturers are steam
reforming for production of hydrogen. Therefore, few options are available for using heavier
feedstocks than naphtha. However, there is a possibility of replacing some of the feed gas
with biogas or other flue gases. In such case the gases need to be economically available in
proximity.

On the other hand there are large numbers of coal based power plants in India. Most of these
plants operate in complete combustion mode. The coal is normally fired with air rather than
oxygen. Practically none of them has carbon capturing capability. As it has been noted, the
prerequisite for syngas production via partial oxidation should be free from nitrogen. If a power
plant operates in IGCC mode then both power and syngas could be made. The syngas could
be either burnt for direct power generation or used for methanol production. If air is used as
firing agent nitrogen needs to be separated after combustion. Alternatively, the air could be
separated before combustion. This co-processing capability adds to lots of flexibility to the
operating plant to cope up with variable demand for power. The excess power during low
demand period could be stored in the form of methanol. It is also possible to produce ammonia
using the nitrogen from the air separation unit.

Unfortunately, today India has only negligible capacity operating in IGCC mode. Probably
only one plant at Tiruchirapalli is operating in this mode with coal. In the near future we may
have some plants coming up with coal gasification. As per projection, IGCC will be introduced
commercially in India during 2037 and during 2042 - 2047 there is likely to be only 30% of the
total coal based power production from IGCC gasifiers [59]. Therefore, possibility for linking the
existing power plants for syngas or methanol production is minimal at least in the near future.
However, carbon dioxide capture and conversion to methanol from these power plants may be
possible if carbon free hydrogen is available nearby.
Only about 12% of the power plants today are operating with natural gas. Many of them are
operating with Combined Cycle [60] but none of them produce syngas with IGCC mode via
partial gasification. Therefore, no syngas is available from these plants as well. It seems that
in power sector there is not much possibility to produce methanol, unless some major changes
are carried out or additional capacity is created. Recently BHEL has started working on a 370
MW Combined Cycle power plant at Karnataka, but again it is apparently not via gasification
(IGCC) [61].

It is technically complex to process coal and gas simultaneously in the same plant. While
coal based ammonia plants go via syngas, the gas based plants use steam reforming route.
Therefore, it is impossible to process coal and gas together in an ammonia plant. It could
however be possible to process heavy residual fuels or even biomass in solid fuel based
ammonia plants. At least this could reduce the GHG burden to that extent.
Mixing of all kinds of solid waste / residue feedstock is possible in fluid bed gasifies. There
are many operating plants handling different types of feedstock either simultaneously or in
blocked out operation. In India, most of our biomass or agricultural residue is utilized in heat
or power generation, with complete combustion or partial combustion, to produce low calorific
value producer gas. Since the producer gas is the product of gasification using air rather than
oxygen, this gas contains large amount of carbon dioxide and nitrogen, making it uneconomical
to convert to methanol [62]. Although it is a good way to reduce carbon emission impact, such
plants as are not suitable for producing syngas for methanol production. However, with addition
of oxygen separation facility upfront the combustor, these plants could be easily converted to
methanol plant.

Methanol and DME Production: Survey and Roadmap | 2017 71