Performance Study of a Microturbine System for Cogeneration Application Using Biogas from Manipueira

Cassava is a commodity that has great importance in food security in many developing countries. The main product in Brazil produced from cassava is the flour, representing approximately 60% of the cassava final destination. As a by-product of this process, we have a wastewater called manipueira. This effluent is highly toxic because it contains cyanidric acid. The manipueira has great potential for biogas production, adding values to the cassava production chain and, also, reducing the content of cyanidric during the methanation process. This study analyzes the energy and economic efficiency of the biogas production from the manipueira produced in a large power plant, using it as an energy source in the feeding of a cogeneration system composed of a gas microturbine and a heat recovery system, whose purpose is to generate electric and thermal energy. The use of the microturbine system instead of other conversion technology is based on the power it presents when it is used for cogeneration, increasing the system efficiency. The study showed that from the economic feasibility calculation, it was possible to determine the cost of producing electricity of US$ 0.16/kWh and of thermal energy of US$ 0.04/kWh with an amortization period of 1.3 years. The results obtained from these analyzes showed that the use of this biofuel is a good choice for energy generation.