Jul 8, 2008

Flue gas or Fuel ? : India's CTL Dilemma

India currently imports 72% of its crude oil consumption. It does have recoverable reserves of 50-71 billion tonnes of coal, currently primarily used for power generation. Here is a recent article on possible externalities from adopting coal to liquids (CTL) technologies in India. The authors (Ananth Chikkatur and Sunitha Dubey) underscore three issues surrounding the implementation of CTL technologies in India : the availability of coal, water requirements for CTL plants, and the emissions from CTL processes.

The article outlined three different proposals submitted by OIL, Tata-Sasol and Reliance. The OIL proposal is a direct liquefaction facility using low-ash, Assam coal, significantly lower in initial process investment (2.5 billion $) compared to Tata-Sasol and Reliance (8 billion $), which use high-ash coals. Both Tata-Sasol and Reliance proposals are expected to produce 80,000 barrels of liquids/day by consuming more than 30 million metric tonnes of coal/year. Accordingly, both Tata-Sasol and Reliance have ~1.4-1.6 billion tonnes of coal as their requirements (over the plant lifetime). This is 2-3 % of India's recoverable coal reserves. There is considerable resistance within the Indian government to open up coal for fuel production, mainly because Indian coal imports for power generation are projected to increase.

According to the article, the water requirements for CTL processes are around 12-14 barrels/barrel liquid fuel. Most of this is projected to come from ground water because of low supply of surface water in the areas where these CTL plants are planned to be sited. However, I think that this is less of a limiting factor, because coal can be transported relatively easily in trains. Therefore, the exact siting of the CTL facility may not be near the mining site itself, but where adequate water supplies are available. Additionally, because the direct liquefaction process uses hydrogen to cook coal to liquids, I would expect the water requirements for direct liquefaction process to be lower than the indirect liquefaction process.

The third challenge outlined in the article is the emissions from CTL plants. Being a believer in industrial ecology, I think that the emissions of H2S and VOCs can be used for fruitful purposes. For example: H2S can be captured and used as a source of sulphuric acid (H2SO4), which is an intermediate in the production of ammonium phosphate-based fertilizers. Therefore, I do not agree with all the points in the article. However, the article does raise valid questions regarding the CO2 emissions from CTL processes.

Summing up, the article does not advocate that India promote CTL plants in a normal business-as-usual scenario. On the other hand, I think that increased demand for coal (arising from CTL and power generation) will lead to improved coal mining technologies. I have been told that coal mines in India are relatively inefficient compared to their couterparts in the US. Why are such technologies not being put in place currently? There is no additional incentive for the coal mining company(ies) to invest because the profit margins on power generation will be small compared to the profit margins on CTL plants. Additionally, I think that high crude prices are here to stay. Therefore, I think a balanced approach, promoting energy conservation as well as cleaner, novel technologies are what India needs to develop sustainably.

More links below:
Is India ready for CTL fuels?
Articles on Indian coal from Ananth Chikkatur, on his website.


deviousdiv said...

The thing about CO2 & wastewater from CTL plants is that these can be effectively utilised for Algae cultivation for the manufacture of Algal Lipids for Biofuels.

But an excellent analysis of India's Coal-to-Liquids potential.


TheLight said...

"The thing about CO2 & wastewater from CTL plants is that these can be effectively utilised for Algae cultivation for the manufacture of Algal Lipids for Biofuels."

Interesting observation, this is another aspect of industrial ecology of CTL plants that I have completely overlooked.

Thanks deviousdiv !

Anonymous said...

Of course it should also remember that the wastewater from a CTL plant comes from 2 sources - the goal gasification black liquour which is is a pleasant witches brew with Phenols and the likes or the reactor product where it contains a diversity of alchols from C1- C8 , not to mention up to 5% of ketones, organic acids, aldehydes and the likes.

without some treatment - requiring coal/energy of some kind, this is probably not suitable for most algal species.

TheLight said...

"without some treatment - requiring coal/energy of some kind, this is probably not suitable for most algal species."

Hmm...thanks for the comment. This puts a dent in the algal biofuels argument. Given that algal biofuels production by itself still requires some energy input (google for semi-technical analyses of GreenFuel's algal biomass process), using additional energy to separate the organics from the "wastewater" only worsens the economics of the plant.

On the other hand, in countries with a history of implementing strong environmental legislation (USA), the CTL plant will be mandated to treat its "wastewater" or recycle this into the FT reactor. Wonder if responsible chemists could cook something useful from the "witches brew" of phenolic compounds or the reactor product.

Anonymous said...

You only need to look as far as Secunda to see what is done today - and what you may have to do - albeit on a smaller scale facility. It is a witches brew - but of some quite high value molcules no longer available by any other route. Still added capex, added energy needed, and questionable returns on the margin.

Anonymous said...

I appreciate CTL for power production. CTL Process and oil production ease energy crunch in India.

At national level its a comparison of CO2 pollution Vs SO2 pollution in cities. India coal produces both in all cities & industries.

CTL is great for all coal from NE states. MEghalaya and NAgaland probably (un-quantified) hold coal more than five times of what Assam (Coal India) has. However this coal has Sulphur, and thus has restricted use. Therefore it is mostly sold through un-regulated market (may be black market also) to un-registered industries all over India, mainly Punjab and U.P. I encourage CTL to convert all that coal in Assam (at the bank of BrahamPutra) and let Assam export power. Business makes sense to me (Students and terrorists can be handled).

TheLight said...

Because the NE Indian coals have high sulfur content, it is imperative that the government set regulations on how the H2S from the flue gases could be recovered. Assuming indirect liquefaction, it should not be technologically challenging to put a H2S/CO2 scrubber operating via the Selexol or Rectisol processes.
"Business makes sense to me (Students and terrorists can be handled)"
I do not think that the credit agencies and banks would think in a similar manner...

In a situation where Indian coking- and steam-coal imports would only increase in the near-future, how can India justify using coal to produce diesel?

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