The Government of India has announced the National Policy on Biofuels, under which ethanol blending of petrol has already reached 10%, and is planned to go up to 20% by 2025. Blending locally produced ethanol with petrol will help India strengthen its energy security. It will enable local enterprises and farmers to participate in the energy economy and reduce vehicular emissions. This national goal can be met by augmenting supply chain for blending ethanol, where stainless steel has a significant role.

According to the Niti Ayog report 'Roadmap for Ethanol Blending in India by 2020-25’ released in June 2021, phased rollout of 20% of ethanol blending by 2025 is very much possible. The report says "Most of the petroleum products are used in transportation. Hence, a successful E20 program can save the country $ 4 billion per annum, i.e., Rs 30,000 crore.” Besides, immense benefits can accrue to the country in terms of energy security, lower carbon emissions, better air quality, self-reliance, use of damaged food grains, increasing farmers' income, employment generation, and greater investment opportunities.

According to Niti Aayog, initially, pan-India ethanol production will be raised from the current about 700 crore litres to 1500 crore litres to make 20% target feasible. Ethanol’s price is around Rs 50-60 per litre and therefore, its blending with petrol is highly cost effective. The differential price policy for ethanol blended petrol announced by Finance Minister in the Budget, making it cheaper by Rs 2/Litre, will further improve its economics.

However, oil marketing companies can face challenges in terms of additional storage tanks for ethanol at refineries/terminals/depots and need for ethanol compliant dispensing units. Thus, the right casing material needs to be considered for its safe storage, supply and transportation. In addition, it is crucial to note that ethanol cannot be stored in an average container because it causes corrosion. Although 100% pure ethanol is not corrosive to most metals, its impurities such as oxygen that cause high level of corrosivity. Some of the contaminants like water, organic acids and chlorides can cause high level of corrosion in ordinary steels and disrupt operations of ethanol supply chain.

There are two methods that can be used to store ethanol: Removing any oxygen content and other impurities in the ethanol sample, which is an expensive process, or storing it in a non-corrosive material which is more cost-effective.

Stainless steel is a corrosion resistant material which makes it the ideal choice for ethanol production and distribution systems worldwide. With stainless steel, pipes can often be made with a lighter wall thickness which makes it easier to distribute. In addition, stainless steel is easy to maintain which reduces costs implied with storage: no paint or other coatings on internal or external surfaces need to be maintained, surfaces remain smooth due to non-corrosion, has a longer life and allows for easier cleaning and disinfection and lower pumping costs. Therefore, stainless steel is the material of choice in ethanol production and distribution systems worldwide.

Secondly, ethanol is a highly flammable material and stainless steel is fire-resistant. Tanks containing ethanol are required to be fire resistant, and stainless steel will prevent the spreading of flames in the case of a standard structural conflagration.

Apart from the general benefits of using stainless steel, the successful impact really depends on the type of project it is used for. For example, tanks for food-grade ethanol are constructed using type 304(L) of stainless steel whereas very large tanks with heavy plates would use a high strength lean-duplex grade such as S32101. Type 304(L) is usually used in the more alkaline operating media of biodiesel processes, such as piping and tubing systems. Type 316(L) is used in places where the acid content is greater and the temperature is more extreme.

To summarize, the type of stainless steel normally required for ethanol projects is generally within grades of 304/316 and used in shell material for distillation columns, shell material for heat exchangers, fermenters and other process tanks, storage tanks, pipes and fittings, plates, tubes for heat exchangers, dryer and other equipment and ethanol tankers. A typical stainless-steel requirement for a 500 kilo litres per day ethanol plant is about 1300 tons. In line with the national priorities, stainless steel industry has geared up to meet this demand, with supplies expected to double this year.

Technical opinion of SSl as the ideal material choice for ethanol
Using the wrong container for ethanol has been a recurring concern at a global scale since the early 1990s: Research carried out by the American Petroleum Institute (API) has shown that Stress Corrosion Cracking (SCC) of steel in fuel ethanol environment is a subject matter where awareness of the issue is growing dynamically as a result of documentation of experiences and research works in progress.

The conversation around the ideal container for ethanol still continues today: In a recent webinar conducted by ISSDA on ‘Stainless Steel for building Ethanol supply Chain’ in association with Nickel Institute, the expert speakers pointed out that stainless steel is in fact used extensively for Ethanol sector in North America and Brazil, who are the world leaders in blending Ethanol in motor fuel. (The Nickle Institute, an international non-profit industry association was established for the purpose of offering guidance and neutral technological advice regarding stainless steel applications). International Energy Agency (IEA) has said that India is set to overtake China to become third largest Ethanol consumer by 2026, next only to Brazil and USA.

The Government has plan to even go beyond E20 fuel and working with automakers to develop flexi fuel engines which can use a range of fuel blends going up to 100% Ethanol, like in Brazil. In any case, whether the auto industry in India can successfully shift from petroleum to flexi fuels will depend entirely on what steps are taken to build and augment the ethanol supply chain down the line to ensure wider availability.

In this context, stainless steel is considered critical for the ethanol eco-system for blending in motor fuel across the entire supply chain. It is estimated that about 1,00,000 tons of high-grade stainless steel will be required to augment ethanol capacity for achieving national goal of 20% blending. The potential is even higher when flexi fuel engines are introduced. Indian stainless-steel producers have already stepped-up supplies to OEMs like Praj Industries, Excel Engineering, Alpha Level etc.to meet this national objective. Indian stainless-steel producers are capable and committed to meet the growing requirement of ethanol industry. However, Government policy support in terms of ensuring a level playing field with respect to dumped and subsidised import of stainless steel is also crucial to enable further investment, so that such critical requirements are met by domestically produced stainless steel only.

References:
1. Aayog, N.I.T.I., 2021. Committee reports: Report of NITI Aayog on Roadmap for Ethanol Blending in India 2020-25. PRS Legislative Research.
2. Stainless steels cost-efficient Materials for Bio Fuel Energy, Kristina Osterman, Nickel institute.
3. First Generation Ethanol Blended Petrol (EBP), programme. NACE International, 2013. ScienceDaily. {Accessed December 10, 2021}
4. Structural Integrity of Materials in Fuel Ethanol Environments, September 2019, DOI:10.5772/intechopen.86383

About the author:
Karan Pahuja is the President of Indian Stainless Steel Development Association (ISSDA).