Comparação entre as rotas via nafta e via etanol para a produção de eteno: análise de custos e emissões de CO2

Abstract

Ethene has a diversified chain of derivatives, which corroborates its economic relevance. The use of ethanol for the production of ethylene (the so-called green ethylene) can lead to a negative emission of CO2, since in addition to the CO2 being captured during sugarcane growth, the fuel is not burnt and CO2 is not emitted. Although more expensive than the traditional route via naphtha, the alcohol chemistry could gain competitiveness if CO2 emissions are valued. This work analyzes two ethene production routes, in order to ascertain their levelized costs and CO2 emissions. Results indicate that the levelized costs correspond to US$ 813.7/ tonne of ethene for the route via naphtha and US$ 1391.9/ tonne of ethene for the route via ethanol. The sensitivity analyses for feedstock prices show that in, some scenarios, given the historical price series, the route through ethanol is already more competitive than the route via naphtha. Moreover, if CO2 emissions are valued at US$ 97 to US$169/ tCO2, depending on the process configuration, the routes would have equivalent levelized costs. Finally, the Brazilian green ethylene could still be introduced into the Chinese market if that valuation reaches US$ 46 to US$ 68/ tonne of CO2. This indicates that the valuation of CO2 could increase the competitiveness of the Brazilian ethylene in the international market, particularly in a country where the production scale of ethene plants make its production less costly than in Brazil.