Thinking about low carbon emissions, the Raízen plant is producing electricity through biogas produced from sugarcane residues
Brazil is one of the largest producers of sugar cane in the world and it is from it that comes the main source of renewable energy in the country. In addition to producing ethanol, the plants use waste from sugarcane crushing to produce electricity. Raízen is an integrated energy company of Brazilian origin with presence in the sectors of sugar and ethanol production, fuel distribution and power generation and the first to produce electricity to be used on a commercial scale in the Brazilian market.
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Electricity production using biogas
First, sugarcane bagasse was used, which started to be burned to feed the boilers, and soon after, biogas, which is obtained from straw, sugarcane filter cake and vinasse. In Guariba, São Paulo, a Raízen plant is producing electricity from biogas on a commercial scale, the first time in the country.
According to the chemical engineer from the University of São Paulo (USP), Marcelo Zaiat, this large-scale experiment is a new milestone for Brazil. At the Raízen plant, vinasse and filter cake are used, which in previous processes were used only as fertilizers. Vinasse is the liquid part left over from the distillation of sugarcane juice. It is extracted from the plant through pipelines and returns to the crop due to its potassium excess. The filter cake, on the other hand, is the solid part that comes out of the filtration of the sugarcane juice, it is rich in phosphorus and is also reused in the field.
Biogas production at the Raízen plant
The vinasse and filter cake are taken to the biodigesters at the Raízen plant, before going to the fields. In this process, a large part of the organic matter in the two residues is transformed into biogas through the action of bacteria.
The methane gas that is produced during the process goes to the surface of the biodigesters and is taken through pipelines to the motor generators, where it is burned and generates electricity.
According to the Automation Engineer, Paulo Miranda, Filter Cake is a strategic residue for them due to its storage that can generate electricity throughout the year.
The search for new energies
One of the initiatives that seek more sustainability is in the laboratory of the Federal University of São Carlos (UFSCar), where equipment is measuring the amount of methane that is released during the biodigestion of waste.
According to UFSCar agronomist Otávio Valsechi, the focus is to remove the methane in the vinasse to separate the carbon due to the presence of hydrogen. The world will move on electrical energy and one of the biggest sources of energy will be hydrogen.
