Nature India | Indigenus

Pollution woes: Is methanol a solution?

Every winter, the northern plains of India are engulfed in toxic fumes, emanating from crop stubble burnt by farmers in the states of Punjab, Haryana, Rajasthan and Western UP. Coupled with that, air pollutants from power plants, and vehicles choke the mega cities. 

Avinash Kumar Agarwal from the Department of Mechanical Engineering at Indian Institute of Technology Kanpur argues in this guest post that methanol economy may offer a potential way out of the obnoxious levels of pollution India is faced with.

Delhi’s winter pollution problem has now caught global attention. The problem gets further complicated every year because of the cold weather conditions that do not allow pollutants to climb up to higher altitudes. Toxic pollutants accumulate near the ground, making a deadly chemical cocktail with secondary organic aerosols nurtured by moisture and sunlight.

The situation is so bad that sunlight can’t penetrate through the carbon black dispersed in the environment. Every winter, therefore, life for more than 250 million people living in the region becomes a chaotic mess of traffic snarls, flight and train delays and low visibility that makes roads hazardous and unsafe. The incidence of respiratory diseases increases exponentially during this time of the year. The economy goes for a toss with massive losses in productivity – millions of man hours are wasted on roads and the public health burden escalates.

The situation has aggravated in the last decade turning Delhi into a gas chamber, where ambient air quality consistently hovers way above safe limits for weeks together. Winters in India’s capital are now deemed life-threatening.

A smog-riddled Delhi day during peak winter, December 2017

A smog-riddled Delhi day during peak winter, December 2017

S. Priyadarshini

Can a methanol economy help?

Besides public policy measures to reduce pollution and stricter implementation of laws to stop crop burning, another way to address the menacing issue could be adopting a methanol economy.

Agriculture residues from farms, currently burnt to prepare the ground for fresh crop seasons, can be used to produce methanol. The carbon monoxide and hydrogen generated by gasification of this massive biomass of low-value feed stock can be used for production of methanol using simple, commercially available technologies. This will not only solve the problem of uncontrolled biomass burning and the associated problem of soot and particulate loading of atmosphere, but has the potential to generate valuable revenue and employment for Indian farmers.

Methanol can also be generated using municipal solid waste, millions of tonnes of which are accumulating in India’s mega cities. The technology for this also exists in the country. Another potential source of methanol is high ash coal, which may not be suitable for power plants or other large-scale economic activities. In theory, India has infinite potential for producing methanol to substitute all petroleum imports.

The methanol thus produced can be used to fire power plants to generate electricity, thus ridding northern India of the fly-ash generated by the power plants, which escapes the most efficient bag filters and electro-static precipitators (ESPs).

Vehicles fuelled by gasoline and diesel can be operated with methanol and di-methyl ether (DME). DME, an ultra-clean fuel known for its soot-less combustion, is a methanol derivative and can be produced by a simple one-step process.

Methanol has also been used for the last several decades as a fuel in Formula-1 race cars, thanks to its properties well suited to spark ignition engines. The octane number of methanol is 105 whereas the octane number of gasoline sold in the market is 91-94. Therefore, methanol can be blended in any proportion with gasoline or used in pure form in the engines. With some modifications in the engine, diesel engines can also operate with methanol as fuel. Older vehicles can be easily altered to use these new fuels using simple kits and new engines can be designed to take advantage of the excellent properties of these fuels. The Engine Research Laboratory at IIT Kanpur has successfully demonstrated methanol-powered spark ignition as well as compression ignition engines. These engines are extremely clean and can easily meet the most stringent emission norms applicable today, and upcoming Bharat Stage-6 norms, with appropriate prototype development.

As the Indian government is now taking a serious look at methanol economy as an alternate, it may be a good time to scale up these efforts through capacity building, production research and utilisation. Methanol economy has the potential to reduce fuel imports, increase energy security from domestic resources and contribute towards a cleaner India.

Limitations

Despite the many benefits it offers, methanol does not come without limitations. Methanol is hygroscopic, meaning it attracts moisture, and could corrode copper and brass engine components when used as a fuel. It is slightly toxic to skin and poisonous if consumed in large quantities. It could pose a health hazard if injected accidentally or intentionally. The gas is odourless, which makes leaks harder to detect. However, the trickiest bit about methanol is its invisible flame.

Cars require more frequent refuelling or larger fuel tanks because methanol has lower energy density. Use of methanol in hilly areas during winters may lead to ignition problems. Methanol is less volatile than gasoline which makes it difficult to fire up or start engines in cold weather conditions. Methanol has limited solubility in gasoline at low temperatures .Therefore phase separation may occur when using ‘gasohol’ blends because of the presence of water traces in methanol. Though methanol emissions are safer than gasoline, methanol results in relatively higher amount of formaldehyde emissions.

Considering the positives of methanol use as a fuel, these limitations can be taken care of during the design of engine and machine components or during the fuel formulation stage, where appropriate additives can be added to overcome the adverse properties of methanol. Methanol has not yet been explored in engines for large-scale implementation with the seriousness it deserves.

A methanol economy can also help regulate the ever-increasing price of gasoline and transport fuel in the world market.

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