Análise de biorrefinaria integrada à indústria de celulose e papel para síntese de amônia

Abstract

The gasification of biomass residues makes it possible to synthesize various compounds, which are currently collected by sources of non-renewable origin, through syngas. The black liquor is part of this list of lignocellulosic residues from kraft pulping. The latter is one of the most used lignin removal methods in the pulp and paper industries. For each ton of processed wood, half a ton corresponds to the portion generated from this waste. Currently, this by-product is burned in the recovery boiler, giving rise to high-pressure steam that is converted into energy. The precipitate from this stage is then dissolved in water and returned to the kraft pulping process, however, it is believed that black liquor has properties that allow its destination for more noble processes in related industries. Thus, the present work aims to evaluate the implementation of a biorefinery coupled to an industrial pulp and paper plant for the production of ammonia, a product with high added value, through the reuse of black liquor. The process was simulated using the UniSim® Design software, in which it was possible to implement gasification with black liquor flow rate of 1,233 ton / h, the air separation unit (ASU) was implemented in a cryogenic distillation column, the gasification in a drag bed reactor, removal of acid gas (AGR) in a solvent absorption tower, Rectisol, enrichment of the gas in H2 in catalytic reactors (WGS) operating at 13.8 bar and, finally, tuning of ammonia in a 0.427 equilibrium reactor on a molar basis. Expecting a plant operating 24 hours a day, with the conditions proposed by this work, an average revenue of 826 ton / d of ammonia is possible. Therefore, the adoption of a gasification system integrated with the pulp and paper industry, makes it possible to maximize the maximum utilization of all the products of this synthesis, in addition to reducing emissions of greenhouse gases, and promoting the possibility of profit for the industry, which may choose to process other products, or sell them as raw material for other industries available on the market.