Source: TH
Context: The Automotive Research Association of India (ARAI) is conducting a pilot project to blend isobutanol with diesel, after ethanol–diesel blending failed.
About Isobutanol:
- What It Is?
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- Isobutanol is a four-carbon alcohol (C4H10O), clear, flammable liquid with higher energy density than ethanol.
- Used as a solvent in paints, coatings, and now being explored as a biofuel blendstock for diesel engines.
- Formation Process:
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- Produced by fermenting natural sugars (cane juice, molasses, grains) using genetically engineered microbes under sterile conditions.
- Requires fermentation tank retrofitting and distillation units to separate ethanol and isobutanol in sugar refineries.
- Aim:
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- Blend with diesel to create a cleaner-burning fuel, reduce crude oil imports, and contribute to net-zero 2070 goals.
- Provide new avenue for surplus ethanol feedstock utilization, supporting sugar sector viability.
- Key Features:
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- Higher Flash Point: Safer than ethanol for diesel blending as it is less volatile and reduces fire risk.
- Better Miscibility: Blends more uniformly with diesel without extra additives (unlike ethanol).
- Energy-Dense: Higher calorific value than ethanol → improved fuel efficiency.
- Flexible Production: Can be co-produced with ethanol using existing infrastructure with minor modifications.
- Emission Benefits: Potential to lower particulate emissions and reduce carbon intensity.
- Applications:
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- Biofuel Blend: Up to 10% blend with diesel (recommended) for transport sector.
- Solvent Industry: Used in paints, coatings, chemical synthesis.
- Aviation & Marine Fuel: Research ongoing for future sustainable fuel use.
- Feedstock for Chemicals: Can be converted to jet fuel, plastics, and rubber intermediates.
- Limitations:
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- Low Cetane Number: Reduces ignition quality, may cause knocking unless additives are used.
- Engine Compatibility: Over 10% blend may impact engine performance and durability.
- Incremental Cost: Additives and blending infrastructure upgrades raise costs.
- Miscibility Concerns: Needs biodiesel as co-solvent for full homogeneity.
