Investigação da Utilização do Glicerol como Matéria-Prima para a Produção de Metanol

Abstract

Glycerol, a byproduct of biodiesel production, has been produced in large quantities in recent years and may prove to be an environmental problem. The study of new ways of exploiting this component has been increasingly investigated with the aim of promoting a profitable destination for biodiesel producers andreducing the impact on the environment. In this sense, this work has the objective of evaluating the feasibility of the injection of a glycerol stream within the natural gas feed in the methanol production process, considering the scenario of an existing plant, without the need of significant changesin the initial design. A mathematical model was developed to generate the data of techno-economic analysis involving two scenarios: the conventional operation of the plant, using only natural gas and the operation of the plant with the partial substitution of the supply of natural gas by glycerol, both scenarios with the same methanol production. The costs associated with the operation were considered as the consumption cost of natural gas, calculated by the price and consumption of the gas at 20ºC and 1 atm. The results indicate that the injection of glycerol is able to reduce the total consumption of natural gas in the plant, which represents an alternative for the methanol industries in regions associated to high prices of natural gas. An analysis of the breakeven point is provided to determine the glycerol price limit that makes its utilization economically feasible, which is US $ 91.3 per tonne of pure glycerol and US $ 80.3 per tonne of crude glycerol (88 % purity). The analysis also considers the variation of the price of natural gas and its impact on the feasibility of glycerol, being verified that with natural gas prices below 6,16 dollars per million btu the use of glycerol is infeasible.