What is Second Generation Bioethanol?
Second generation biofuel technologies have been developed because first generation biofuels manufacture has limitations. First generation biofuel processes are useful but limited in most cases: there is a threshold above which they cannot produce enough biofuel without threatening food supplies and biodiversity. Many first generation biofuels depend on subsidies and are not cost competitive with existing fossil fuels such as oil, and some of them produce only limited greenhouse gas emissions savings. When taking emissions from production and transport into account, life cycle assessment from first generation biofuels frequently approach those of traditional fossil fuels.
Second generation biofuels however can help solve these problems and can supply a larger proportion of our fuel supply sustainably, affordably, and with greater environmental benefits. Bioethanol is the principle fuel used as a petrol substitute for road transport vehicles.
The principal of second generation biofuel processes is to extend the amount of biofuel that can be produced sustainably by using biomass consisting of the residual non-food parts of crops grown specifically for energy use including corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses and sorghum plants. The process can also utilise industrial waste such as woodchips, skins and pulp from fruit pressing, etc. The problem that second generation biofuel processes address is to extract useful feedstocks from this woody or fibrous biomass, where the useful sugars are locked in by lignin, hemicellulose and cellulose
BioEthanol burns to produce carbon dioxide and water. Ethanol itself is a high octane fuel and has replaced lead as an octane enhancer in petrol. By blending ethanol with gasoline we can also oxygenate the fuel mixture so it burns more completely and reduces polluting emissions. Ethanol fuel blends are widely sold in the United States and South America and only flexible fuel vehicles can run on up to 85% ethanol and 15% petrol blends (E85). The Model T Ford was originally produced to run on Ethanol.
How do we produce 2G Bioethanol?
TMO has developed a fully integrated process for the production of second generation bioethanol. We only focus on the non-food parts of crops, such as stems, leaves and husks that are left behind once the food crop has been extracted.
Our technology has been specifically developed to break down the fibrous cellulosic material or feedstock and convert into a fermentable broth from which cellulosic ethanol can be produced. This process has been refined and engineered around the proprietarily developed thermophilic (heat-loving) Geobacillus bacteria and is a fully integrated pre-treatment, high solids enzyme hydrolysis and fermentation process
The integrated TMO Process can be broken down into a number of steps:
This prepares the feedstock for the best possible enzyme hydrolysis using steam with mild conditions which are specific to the feedstock. This breaks the material down into a more manageable solution of cellulose fibres.
High solids enzyme hydrolysis
The pretreated material at high solids concentration is treated with to a feedstock-specific enzyme cocktail at temperatures between 50-60°C to further break down the cellulose. An optimum cellulose sugar stream is transferred to the fermentation system.
The TMO organism uses its inherent enzymes to break down the shorter cellulose and hemicelluloses chains in the hydrolysed material into simple sugars to generate alcohol. Fermentation is usually between 55-65°C.
Finally, the fermentation broth is sent to a separation and dehydration system where ethanol is distilled and recovered.