Ethanol and humans have a tumultuous connection. Of course, a lot of people consume it. Additionally, efforts to scale it up as a fuel and a chemical feedstock have been made for decades. The hope is that the chemical and energy sectors’ dependency on petroleum may be broken and their impact on the environment significantly reduced with the correct technology for producing and using ethanol, as reported by C&en.
Long debate
Conventional ethanol relies on sugars extracted from corn, sugar beets, and sugarcane.
To top it off, the ethanol fermentation process yields carbon dioxide as a by-product.
Yet ethanol has a good side too—namely, the crops it is derived from pulling CO2 from the air.
Critics, advocates, and academics have long debated which of the two sides prevails in the battle to find a fuel and chemical feedstock that has fewer greenhouse gas (GHG) emissions than petroleum.
Cellulose, in the form of lignocellulosic biomass, is abundant in agricultural and forestry waste.
Examples include corn stover—the stalks, leaves, and husks left over after kernels are harvested—as well as straw, and sugarcane bagasse—the dry, fibrous pulp left over from sugar production.
Additionally, converting such biogenic carbon into lasting items rather than fuel results in a specific type of CO2 sequestration. A new age for ethanol, according to some industry observers, is about to begin after decades of failed attempts due to the worldwide push for net-zero carbon emissions and an improved array of cellulosic technologies.
Promises of the past
Despite many attempts, cellulosic ethanol often called second-generation or 2G ethanol, has proved much more difficult to produce at scale than its first-generation cousin made from starch and sugar.
In the 2010s, a handful of ambitious companies spent hundreds of millions of dollars to build cellulosic ethanol plants in the US.
In 2017, Poet and DSM said those problems were sorted out.
Meanwhile, DSM sold its cellulose-to-sugar enzyme technology to Versalis, a subsidiary of the oil company Eni, in late 2022.
In 2015 it opened a $200 million plant in Nevada, Iowa, promising it was the first of many.
In a similar story, the renewable energy developer Abengoa started making ethanol from corn stover in 2014 at a facility in Hugoton, Kansas.
Praj opened India’s first commercial-scale cellulosic ethanol plant in August.
Owned by Indian Oil but built and operated by Praj, the plant will yield 30 million L of ethanol per year from rice straw when it reaches full capacity.
All three oil companies are owned or partially owned by the Indian government.
Start-up troubles led the firm to write off most of the plant’s value in December, but owning and operating such plants was never the main business plan, says Ralf Hortsch, Clariant’s head of marketing and strategy for biofuels and derivatives.
“We also sell the microorganisms that produce the enzymes integrated into the plant and the yeast that ferment the sugars to ethanol.”
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Source: C&en