US tyre manufacturer
Tire & Rubber Company plans to use silica extracted from rice husk ash, which is cheaper than getting it from sand. Silica also helps to reduce the rolling resistance in tyres by about 20% compared with traditional carbon black-filled tyres. Nabeel A Khan recently met Goodyear’s global R&D head, Surendra Chawla, who has been with the company for 34 years. He said Goodyear is working on an airless tyre with NASA. Excerpts from the interview:
How did the idea of extracting silica from rice husk come about and what is the advantage of this technology?
The concept came to us at a conference in the United States for small business innovations and research. Here, we saw one of these small business entrepreneurs with the concept of extracting silica from rice husk ash. So our instinct was to look at this opportunity in parts where rice is grown, like China, India, Brazil, even the United States. We found there are many scientists in research institutes working to try and extract silica from husk ash. What can be done with husk? About 20% of paddy by weight is husk. It’s a huge volume. So what they do is that they burn this husk to generate electricity. And when they burn the husk to generate electricity, the remainder is the ash.
How cost-effective is this compared with extracting silica from sand?
There are two aspects to this. The cost, of course, is lower. But the bigger aspect is that the energy consumed in extracting silica from the traditional source, which is sand, is much higher. To extract silica from sand, you have to heat the sand up to 1,400 degrees Celsius.
We don’t have a plant yet to produce silica from husk ash – only a pilot facility. But the power required, the temperature required for extracting silica from ash is only 100 degrees Celsius versus 1,400 degrees Celsius in the case of sand.
What is the advantage of using silica in tyres instead of traditional carbon black?
Traditionally, we use carbon black to provide strength to rubber. But silica has certain unique properties over carbon black. It is mostly silica that we are using today in the tread (the part of the tyre that’s in contact with the road). Silica gives much better strength, stiffness to the tread and it provides lower rolling resistance. So by replacing carbon black with silica, we can reduce the rolling resistance by almost by 20% and improve the fuel economy by about 3-5%. However, silica is costlier, so the application is limited right now. Currently, carbon black is about one-third to one-fourth the cost of silica.
Do you think there is a way to reduce the cost? How do you see the consumption of silica in tyres increasing?
This is right now in a very early stage. But over the years, it can become the most commonly used filler material in tyres. The consumption of silica in tyres will continue to grow. Today, the level of silica consumption as a filler material versus carbon black is very small — about 10%-15%. The growth we expect is about 7-8 % every year, depending on the markets.
Is there a way to use synthetic rubber in place of scarce natural rubber?
Goodyear has a very interesting programme for that very reason — sustainability. We do have a plant where we produce our own synthetic rubber. But we are also collaborating with a biotech company in the US, which is now owned by DuPont, to produce Biolsoprene, which is used to make synthetic rubber.
Globally, what are the trends in terms of radial and bias tyres? What are the innovations that could come up in radial tyres?
The world has changed quite a bit in terms of moving from bias to radial tyres. In parts like India, it is also moving in that direction but it is still in a transition phase and it will continue to grow. As our infrastructure in India becomes better, that transition will take place.
The other technology we are working on is a non-pneumatic tyre. We also have a spring tyre, for which we are working with NASA. It is non- pneumatic. This type of tyre doesn’t require air. But at the same time, you have to see where that technology is. If it is non-pneumatic, it will be much heavier. Will that provide enough fuel efficiency? A lot of research work is still going on. Will it happen in our near future in consumer tyres? I think it will have mixed applications.