Propuesta de diseño de una planta de tratamiento de aguas amargas proveniente de la refinación del petróleo aplicando el simulador Aspen Plus®

Abstract

The aim of this research is a design proposal for a sour water treatment plant applying the Aspen Plus® process simulator. Bitter water is the effluent of some of the fundamental processes within oil refinement, such as: fluid catalytic cracking, hydro-treatment, hydrodesulphurization and visco-reduction. Bitter water has a high percentage of ammonia and sulfuric acid that in order to be eliminated into natural sources must first undergo treatment in which said components are separated.

For the simulation a bitter water capacity of 36000 kg/h was established with an ammonia concentration of 5000ppm and a sulfuric acid concentration of 1000ppm based on data gathered on our technical visit at the Esmeraldas State Refinery. For the simulation the NRTL thermodynamic model was used.

The key equipment to accomplish the goal of removing contaminants from bitter water is the exhaust column, which was initially designed from a basic model DSTWU to obtain the necessary parameters, such as the number of stages, supply stage, reflux and warming service in the reboiler. Once the initial parameters had been obtained a 21 stage RADFRAC rigorous column was designed, with supply at stage 8, without a condenser and with a thermosiphon reboiler, from where the scrubbed water exits with a NH3 concentration of 0,0137ppm and 2,1290e-13ppm of H2S, which complies with what is established in the ECUADORIAN NORMS FOR ENVIORNMENTAL QUALITY AND DISCHARGES OF EFFLUENTS.