Union Road Transport Minister Nitin Gadkari on August 7, 2024 said the government will allow mixing of lignin (bio-bitumen) up to 35% in petroleum-based bitumen, a large part of which is imported from other countries.
Bitumen
Bitumen, also known as Asphalt, is a black substance produced through the distillation of crude oil and is widely used for making roads and roofs.
Asphalt also occurs naturally, similar to crude petroleum. Like petroleum, asphalt is a hydrocarbon made of the remnants of long-dead living organisms, such as algae.
90% of Indian roads are using bituminous layers. Bitumen consumption in 2023-24 was 88 lakh tonnes. In 2024-25 it is expected to be 100 lakh tonnes. 50% of the bitumen is imported. And annual import cost is ₹25,000-30,000 crore.
Bio-bitumen
Bio-bitumen is a type of asphalt mixture that is made with lignins from various waste streams. Lignins are polymeric biopolymers that can be found in the cell walls of plants.
When these lignins are blended with other polymers, such as bitumen and sulfur, they form a binding agent that can be used in asphalt. This is called bio-asphalt or bio-bitumen, and it has many benefits over conventional asphalt.
Thus, bio-bitumen is a sustainable, petroleum-free alternative to traditional bitumen derived from fossil fuels.
Indian Institute of Petroleum, Dehradun, had developed bio-bitumen from paddy straw. One tonne of parali (paddy straw) is giving 30% of bio-bitumen, 350 kg of bio-gas and 350 kg of biochar.
The substitution of up to 35% bio-bitumen into bitumen is successful.
The foreign exchange saving is expected to be ₹10,000 crore and a patent has been already submitted.
The cost of petroleum-based bitumen is ₹50 per kg while the cost of bio-bitumen from biomass (rice straw) is ₹40 per kg.
Indian Oil Corporation has a project in Panipat for making one lakh litres of ethanol per day from rice straw apart from 150 tonnes of bio-bitumen per day, and 88,000 tonnes per year of bio-aviation fuel.
Envisaged benefits of bio-bitumen are reduction in bitumen import, reduced Green House Gas (GHG) emissions and opportunity for farmers/MSMEs to generate revenue and provide employment.
