The Institute of Chemical Technology (ICT), Mumbai has developed India’s first home grown technology to convert biomass to ethanol with speed and efficiency.
The technology which converts agricultural waste into ethyl alcohol, or bio-ethanol, is superior as the rate of conversion is four times faster than other technologies currently available in the international market.
With other technologies, the time taken is 4 to 7 days, the one developed by the DBT-ICT Centre for Energy Bio-Sciences team at Institute of Chemical Technology; Mumbai converts it in 18-20 hours and produces about 300 litres of ethanol per ton of biomass. The produce can be blended with petrol to be used in vehicles as fuel.
The country’s first second-Generation (2G) Ethanol plant was inaugurated by Union Minister for Science and Technology and Earth Sciences Dr Harsh Vardhan at Kashipur in Uttarakhand.
Subsequently, the technology was transferred to Bharat Petroleum Corporation Limited (BPCL) and Hindustan Petroleum Corporation Limited (HPCL) to build commercial scale biomass ethanol plants based on the technology. The plants are scheduled to be operational by 2018.
Memorandum of Understandings (MOUs) were signed by Institute of Chemical Technology with the petro giants BPCL and HPCL for technology transfer and building commercial scale biomass to ethanol plants entirely based on the technology developed by the DBT-ICT Centre for Energy Biosciences.
BPCL is setting-up 2G Biomass Ethanol Bio-refinery in Bina, MP with a capacity to process 400 tonnes/day of Biomass (equivalent to 100 KL/day of ethanol generation capacity). The plant is expected to produce around 32000 KL Ethanol/year. A 100 KL per day capacity Second Generation Ethanol plant is proposed to be set up by HPCL in Bhatinda, Punjab. The proposed plant is expected to utilize approx. 140000 tonnes of biomass per year and yield 32000 KL of ethanol.
Using agricultural waste as raw material will deter farmers from burning it away, as practised by most rice and wheat farmers in the Indo-Gangetic plains. Production of bio fuel, in turn, will not only help cut down the country’s oil imports, but also reduce carbon dioxide emissions into the atmosphere.
“The technology is suited for both Indian and global needs and it is projected to be capable of converting all types of agricultural residues like bagasse, rice and wheat straw, bamboo, cotton stalk, corn stover, wood chips to ethanol in less than 24 hours, with optimum product yields,” Dr Harsh Vardhan said during the inauguration of the Kashipur plant.
He pointed out that if successfully operated and scaled-up, it will establish India as a major global technology provider in the arena of renewables and reduction in carbon-emissions, besides effecting considerable savings in import of crude-oil.
He added that more such examples are needed, for the initiatives like Make in India and Swachh Bharat Abhiyan to be truly successful and that such technological breakthroughs can make India stand out as a leader in the worlds struggle to save the earth from challenges of global warming,” he noted.
The Government has set a mandate of 5 per cent blending of renewable biofuel in both petrol and diesel. While diesel biofuel blending is near zero, the petrol blending today stands at an overall of about 3 per cent in the form of first generation (1G) or molasses-based Ethanol. While the annual requirement of 1G-ethanol stands at about 500 crore litre, the current total installed capacity is about just 265 crore litre.
A technological breakthrough
The technology developed by ICT involves three steps—chemical fractionation, enzymatic hydrolysis and fermentation. In the first step, lignocelluloses are broken down to cellulose, lignin and C5 sugars by means of acid fractionation. A mixture of cellulose and lignin through alkali fractionation then separates to cellulose and lignin streams.
Cellulose through enzymatic hydrolysis breaks down to C6 sugars.
The non-sugar organic components can be simply converted into energy by direct burning while inorganic silica can be recovered and sold as by-product. The burning provides steam, as energy, required for ethanol distillation, while both C6 and C5 sugars through fermentation yield the desired ethanol.
While fermentation of C6 sugars is relatively simple, C5 sugars (xylose) need special yeast strains. In the new technology, innovative fermentation has led to innovative bioconversions of both C6 and C5 sugars to ethanol. High-density continuous fermentation with controlled concentrations of clean sugars gives high-speed efficient fermentations with high yields.
At present, the cellulose degrading enzymes used in the process are imported, and the challenge is to produce these enzyme production technologies in India. The DBT-ICT Centre is working alongside several other Indian institutes to meet this objective.
Today, the technology stands out as potentially one of the best in the world for efficient and controlled fractionation of biomass to its components cellulose, hemi cellulose and lignin; rapid enzyme hydrolysis of cellulose with enzyme recycle and reuse using a patented technology; and high cell density continuous fermentation of both C6 and C5 sugars using our own developed strains to provide rapid and efficient fermentation.
Biomass structure is complex and varies with feedstock and its age. The challenge is to treat all types through a single technology and yet obtain intermediates of a consistent quality. Specific enzymes break cellulose structure in complex ways. Understanding their action is key to their effective use at a large scale.
A two-step controlled chemical deconstruction of any biomass gives consistent high quality of cellulose. Xylose and lignin is recovered for processing. Carefully designed slurry flows permit rapid reactions with high efficiencies. This followed by a continuous and rapid enzyme hydrolysis yields clean sugar in high yields for efficient fermentation.
Important features of the DBT-ICT 2nd generation ethanol technology are low capital cost compact technology; continuous processing from size reduction to fermentation; recycle and reuse of chemicals, enzymes and water; high recoveries of sugars with almost zero toxics formation. The last feature helps effective production of sugars that can also be diverted to other products.