The sunliquid® process: Bringing new proven solutions for commercial cellulosic ethanol production to Thailand

Sustainability is not a hype. It marks a turning point for the global economy. With the Paris Agreement from 2015, a legally binding international treaty on climate change, 195 countries gave their commitment to limit global warming to 2 degrees by 2050 compared to preindustrial levels. Following Europe, the US has recently committed to enable the transformations required to reach net-zero by 20501 while China has outlined a roadmap to become carbon neutral by 2060. Other countries are globally following these examples.

Spotlight on Thailand

Looking at Thailand, the prime minister Gen. Prayut Chan-o-cha’s participation at the 26th United Nations Climate Change Conference (COP26) in Glasgow, United Kingdom has enabled Thailand to solidify its role in fighting climate change on the global stage and created awareness within the global community to achieve carbon neutrality within 2050 and net zero emissions by 2065.

In addition, Thailand has promoted the production and use of ethanol fuel in order to reduce energy imports, to promote the use and value of agricultural raw materials, and consequently to reduce carbon emissions compared to fossil fuels. According to the Alternative Energy Development Plan 2018 – 2037 (AEDP2018), the goal is to promote the production and use of ethanol fuel to reach 7.5 million liters per day by 2037. However, in 2020 and 2021, sugarcane production dropped to 74.89 and 66.65 million tons, respectively. In addition, cassava production did not increase enough to serve the demand. As a result, the prices of the molasses and cassava raw materials were higher, and the ethanol price rose to 25 – 26 baht per liter. This has caused the repeated cancellation of the phase-out of gasohol E10 octane 91, which is an important mechanism to increase the volume of domestic ethanol fuel use. Most recently, this phase-out has been postponed until the end of 2022.  

Possibilities to bring sunliquid® to Thailand

Apart from sugarcane molasse and cassava, which are limited, other materials can also be used to produce cellulosic ethanol, such as cassava pulps and rhizomes, sugar cane tops and leaves, rice straw, and empty fruit bunches (EFB). If the harvesting process and collection of these raw materials can be developed to be economically feasible for cellulosic ethanol, it will bring additional options to support Thailand’s targets. For example, there is a high potential in the use of regional rice straw as a raw material, which is currently underutilized. According to the assessment of the AEDP2018, up to 27 million tons of rice straw remain in the field, equivalent to up to 14 million liters of ethanol per day. At rice straw price of 1,200 baht per ton, moisture 12 percent, the feedstock cost is only 6-7 baht per liter of ethanol. Rice straw is valued at up to around 189 liters ethanol or 4,600 baht per ton, which could reduce energy imports from abroad by as much as 125,000 million baht per year.  

This feedstock could be utilized with Clariant’s sunliquid® process that converts regionally sourced agricultural residues into high quality bioethanol.  A one-hectare wheat field will produce about 2-3 tons of straw on average. At an average humidity of 13 percent, this straw can be converted to about 550 liters of ethanol using the sunliquid® process. Translating to a yield of just over 20 percent, this means five tons of straw will give nearly one ton of cellulosic ethanol (1 t = 1267 l). The two by-products of this process are lignin and vinasse, the latter can be used as an efficient organic fertilizer in agriculture.

The sunliquid® process shows a flexibility on a broad range of feedstock. Process conditions & biocatalysts were developed & performance runs executed in our pre-commercial plant for a wide range of lignocellulosic biomass.

The sunliquid® process shows a flexibility on a broad range of feedstock

“The technology was successfully implemented in pre-commercial plant in 2012 and five sunliquid® technology licenses have been sold in both Europe and China since then. The milestone of the construction completion of our first commercial sunliquid® plant in Romania underlines our commitment to building a more sustainable future”, says Christian Librera, Clariant’s Head of Business Line Biofuels and Derivatives. 

How does sunliquid® work?

The sunliquid® process is divided into four technological sections. In the first step, the straw is shredded and thermally pre-treated to open the stable lignocellulosic structure. This makes it easier for the enzymes, added in the second production step, to access the sugar chains. Our pre-treatment process has been optimized so that the need for any chemicals could be eliminated.                                                                                                                                                                                

In the second step, enzymes are added to the pre-treated straw to liquefy and split its cellulosic and hemi-cellulosic components into different sugar types. As part of the integrated enzyme production, a small fraction of the sugars is used to feed microorganisms to produce feedstock and process-specific enzymes. These enzymes act to break up the long cellulose chains into fermentable sugars, such as glucose, xylose and arabinose. The insoluble woody component of the straw, lignin, is separated to generate energy which can be used to operate the cellulosic ethanol production plant.                                                             

In the third step, the C5 and C6 sugars are simultaneously fermented into ethanol in a one-pot reaction. Our proprietary yeast strain is specifically modified and adapted to these conditions, leading to a 50% higher ethanol yield, compared to standard yeasts.

In the final step, a highly optimized purification process removes the water to yield pure ethanol.

Clariant’s sunliquid® process

Second generation biofuels produced from non-edible feedstocks offer additional CO2 savings compared to first generation biofuels.

The bioethanol produced using the sunliquid® process helps decarbonize the transport sector by providing up to 95 percent CO2 savings compared to fossil fuel, and by as much as 120 percent if carbon sequestration is considered and used as part of the production process. In other words, a sunliquid® plant with an output of 50,000 tons per year can help avoid ~120,000 tons of CO2 emissions per year, equivalent to the annual CO2 emissions of ~35,000 cars.

Producing cellulosic ethanol from agricultural biomass could not only help to reduce carbon footprints but also prevent burning of biomasses, particularly, rice straw and sugarcane leaves. Farmers currently still burn them because of less labor & cheaper harvesting costs for sugarcane, and a faster preparation of the rice fields for next round of crop. These activities contribute to significantly increasing smog and PM2.5 pollution at crisis levels every year, especially in the period of November to March in the main agricultural provinces, Bangkok and its surrounding provinces. In Bangkok, scientific estimates for biomass burnings’ contribution to the PM2.5 levels vary from 24percent to 38percent, with the majority of it coming from sugarcane and rice burning2.

sunliquid® in action

On October 15 2021, Clariant announced the official completion of its sunliquid® cellulosic ethanol plant in Podari, Romania, 50,000 TPA of ethanol, consuming around 250,000 tons of straw. The completed construction is an important next step for the commercial deployment of sunliquid® technology, with a range of 12kta to 50kta, and thus supports Clariant’s sunliquid® licensing business strategy. The plant in Podari, Dolj county, is built on a 10-hectare area on which construction was initiated in 2019 with up to 800 workers onsite. Contracts with more than 300 local farmers have been signed to ensure the supply of the necessary feedstock.

This investment also brings substantial economic benefits to the region. By locally sourcing feedstock, greenhouse gas emission reduction can be maximized. Also, additional business opportunities will arise along the regional value chain. Co-products produced by the process will be used for the generation of renewable energy, making the plant independent of fossil energy sources. Therefore, the resulting cellulosic ethanol is an almost carbon neutral second-generation biofuel. Besides application as a drop-in solution for fuel blending, this offers further downstream application opportunities into bio-based chemicals and for sustainable aviation fuel.

Summary

Clariant’s sunliquid® is ready to use technology that can provide sustainable cellulosic ethanol with commercial proven technology, flexibilities in both feedstocks, project scalability, and sugar platform for other biobased chemicals. It is a prime example for circular economy which is not only help to increase farmers income but also it is a potential solution for decarbonization and fuel ethanol promotion under Thailand AEDP2018.

For more information contact:
Dr. Seksan Phrommanich, Business Development Manager SEAP, Business Line Biofuels & Derivatives | Email : seksan.phrommanich@clariant.com

CLARIANT (THAILAND) LTD.

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