Page 162 - AWSAR 2.0

138 || AWSAR Awarded Popular Science Stories - 2019
production economics of methanol produced, making it costly. Then, the question arises: What about coal? India has abundant coal reserves. A recent analysis estimates the geological coal reserves of India to be approximately 300 billion tonnes. Then why is the coal of Indian origin not used for production of methanol? In order to elucidate the reason, it is necessary to understand the process for conversion of coal to methanol.
For production of methanol, the mined coal is washed, and subjected to a process called gasification at high temperature and pressure. Gasification of coal leads to the formation of synthesis gas, which is essentially a gaseous mixture of carbon monoxide (CO) and hydrogen (H2) along with impurities. This synthesis gas is supposed to be fed to a reactor for its conversion to methanol by a reaction between CO and H2. This gas- phase reaction is extremely slow even at high temperatures and pressures
and hence a solid material
called a catalyst is added to the
reactor to speed up the reaction
of methanol production. This
catalyst is, however, extremely
sensitive to the presence of
impurities in the reacting gas
as they can literally poison the
catalyst. A poisoned catalyst no
more speeds up the methanol
production reaction, becomes
useless quickly and needs to
be replaced. That is why, it is
essential to identify and remove
any contaminants present in the
syngas before feeding it to the
methanol production reactor.
The clean-up of the
syngas produced, hence, is an
important, inescapable bridge
between coal gasification and methanol production. Such clean-up processes have
been established worldwide for syngas derived from high-grade coal. However, as compared to the coals of Australian or American origins, Indian coals are low-grade and have lower energy content and produce large amount of ash. Further, they also retain more volatile impurities. Thus gasification of Indian coal leads to syngas, which has more and diverse impurities. This ‘dirty’ nature of syngas produced from Indian coal forms a major barrier in the methanol production process. The syngas clean-up processes established worldwide developed for high-grade coal cannot be directly applied or simply modified for Indian coal-based syngas due to the aforementioned heterogeneous composition oftheIndiancoal.ThisisthereasonwhyIndia does not have even a single establishment for methanol production from coal.
Hence, if we intend to set up the roots of coal-based methanol production industry in India, the design of a commercial technology for clean-up of the contaminated raw syngas produced from Indian coal is a must. This is where our research comes into
picture.
The primary objective
of this research is to develop the first, one of its kind, commercially viable process for removal of contaminants from raw syngas produced from low-grade Indian coal so as to make it suitable for methanol production. Your next question probably would be: How easy is it? To answer this, the nature of the impurity in coal-derived syngas needs to be studied.
As mentioned earlier, gasification of Indian coal leads to syngas which has more and diverse impurities. The
Transportation sector constitutes a major part of these energy demands and we have been relying upon imported crude oil and the fuels derived from it to meet them. However, the crude oil is available only in limited quantity under the earth’s crust. Further, burning of the fuels derived from the crude-oil results in emission of several harmful compounds in the atmosphere leading to air pollution.