Viabilidade econômica da implantação de uma etapa de purificação de biogás no processo de geração de energia elétrica em um abatedouro de aves

Abstract

The use of industrial waste as an alternative energy source from the use of biogas produced in biodigesters is already proven. However, although there are impurities that affect the combustion process, there are still few studies of biogas purification processes with emphasis on power generation. With the growing competition between companies, invest in reuse of wastewater has been an excellent choice for power generation and, consequently, increase the processes efficiency and reduce manufacturing costs, besides benefit the corporate image. But, that biogas can be used as an energy source, he needs to be purified, removing the hydrogen sulfide (H2S), which causes harm to human health and damage to electricity generation system. Therefore, the biogas purification is an important step to increase efficiency in the use of this alternative energy. The study aimed to evaluate the economic feasibility of a biogas purification system which uses the method of H2S removal by chemical absorption in Fe-EDTA solution, installed in a poultry slaughterhouse in the western Paraná. The methodology used was the annualized investment costs, making a comparison between the processes of energy generation with biogas unpurified and purified. In the economic analysis, the annual interest rate used was 7%, applied by FINEP, financer of the project of energy generation of the poultry slaughterhouse. The availability of the power generation plant was considered in 365 days, and the investment payback period, in 10 years. As revenue, was considered only the production of electricity for own industry consumption. The economic analysis found that inclusion of the purification step changed the biogas cost of 0,157 R$/m³ to 0,165 R$/m³, and the electricity cost of 0,218 R$/kW to R$ 0,222 R$/kW. Despite increases in the unit costs of the products, the purified biogas scenario presented IRR of 22,5% and payback time of 3 years and 11 months, better than the unpurified biogas scenario, which showed a IRR of 22,42%, and payback time of 4 years, which shows that the implantation of the biogas purification step in the electricity production is feasible, and that the system may become even more lucrative with the inclusion of new recipes, taking advantage of its full potential.