Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Comparison of energetic model applied to desalination unit with multiples effects
Submission Author:
Erick Breno Azevedo dos Santos , RN
Co-Authors:
Erick Breno Azevedo dos Santos, Eduardo José Cidade Cavalcanti
Presenter: Eduardo José Cidade Cavalcanti
doi://10.26678/ABCM.COBEM2023.COB2023-0766
Abstract
In the past years, the phenomenon of El niño is causing drought in some regions and heavy rains in others, intensifying the demand for fresh water in industrial activities, agriculture and domestic use. The fresh water has become a scarce resource in some locations, and desalination has gained importance as a sustainable option for solving the problem. There are several energy sources used in desalination plants and equipment. The main problem is the high cost of operation, resulting in a more expensive product than the traditional methods used for potable water production. The use of cogeneration with desalination plants is a very effective solution to increase the performance of the desalination process. This system has shown higher thermodynamic efficiency when compared to isolated processes, due to it allows the use of waste thermal energy associated to with high discharge temperature of exhausted gases. Aligned with this method, the use of multi-effect evaporators coupled with steam thermocompressors increases the efficiency of thermal desalination. The present study evaluated a gas turbine electric power generation system with capacity of 40 MW coupled to a multi-effect thermal distillation unit with 6 effects driven by a steam thermocompressor (MED-TVC). The process is modeled using mass and energy balances. A model in literature uses the specific heat constant between the mass flow rate of input and output of brine. The effect of boiling point elevation (BPE) due to salinity of the water was considered. The research has developed a thermal model based on the enthalpy of the saline solution at each mass flow. The models were compared. The power cycle, natural gas combustion and water desalination process were evaluated by energy analysis. The data of base model has a daily production of 13,112 m3 of desalinated water for 17.81 kg/s of motive steam, resulting in a Gain Output Ratio (GOR) of 8.52
Keywords
Energy Recovery, desalination, cogeneration, Multi-effect distillation, Gas Turbine
