Journal of Applied Research in Chemical-Polymer Engineering

Abstract Research subject: The scarcity of freshwater resources and the rapid growth of population have made the development and deployment of efficient desalination technologies an undeniable necessity for securing reliable supplies of drinking and industrial water. In this regard, the present study focuses on the modeling, validation, and techno-economic assessment of two widely applied technologies, reverse osmosis (RO) and multi-effect distillation (MED), as well as their integration in standalone and hybrid configurations.
Research approach: In the modeling stage, the key components of each process, including pumps, pressure exchangers, pretreatment units, and main desalination modules, were simulated with high accuracy using established mathematical correlations. Calibration and validation were carried out with the aid of WAVE software and field data from existing industrial plants, ensuring consistency between simulation results and practical operation. Four configurations, including RO, MED, RO-MED, and MED-RO, were investigated under identical feedwater conditions (50,000 m³/day, salinity of 30,000 mg/L) and defined operational constraints. The evaluation criteria included product water quality, recovery ratio, electrical and thermal energy consumption, and specific water production cost.
Main results: The results showed that, among the four standalone and hybrid RO and MED scenarios, the standalone RO system had the lowest levelized cost of water at 0.386 USD/m³, making it the most economical option. Its cost was about 38%, 19%, and 58% lower than MED, RO-MED, and MED-RO, respectively. In contrast, the product water quality of RO was 93%, 42%, and 47% lower than these alternatives. Sensitivity analysis revealed that increasing electricity price raised the cost of standalone RO by up to 78%, while higher fuel cost increased the MED cost by 85%. Moreover, variation in the interest rate had the strongest impact on MED-RO, raising its cost by up to 40%. In addition, the RO-MED hybrid configuration proved to be an economical alternative compared with other options, while ensuring higher water quality. These findings highlight that the optimal choice of technology strongly depends on local conditions such as energy price, availability of waste heat, and required product quality.

Abstract Research subject: This study focuses on the design and evaluation of a novel integrated system for simultaneous multi-generation production. The objective is to develop an efficient process capable of co-producing four outputs: electricity, heat, cooling, and pure carbon dioxide. The main innovation lies in the combined use of biogas produced from corn cob fermentation and a carbon capture unit with net-negative emission capability. Distinctive features of this design include thermal integration, such as utilizing recovered heat from gas turbine exhaust to supply energy to the carbon capture unit, and leveraging the cooling potential from the liquefied natural gas (LNG) process.
Research approach: The designed system comprises key components, including a gas turbine, a chemical carbon dioxide absorption unit, an Organic Rankine Cycle for waste heat recovery and additional power generation and a hot water boiler for heating supply. The system was simulated using Aspen HYSYS software. For a comprehensive performance evaluation, four parallel analyses were conducted on the system: energy analysis, exergy analysis, economic analysis, and finally, a sensitivity parametric analysis. The aforementioned parametric analysis was performed to examine the impact of key operational parameters on performance indicators and to propose improvement strategies.
Main results: Based on the simulation results, the overall energy efficiency of the process was calculated as 52.19%, the exergy efficiency as 40.59%, and the specific electrical efficiency as 41.96%. A major advantage of the system is approximately 34.1% fuel savings compared to separately producing the same products. From an economic perspective, the total system cost rate was estimated at $ 496 per hour, and the cost per unit product at $ 25.74/GJ. Exergy analysis also revealed that the total exergy destruction within the system equals 8694 kW. Key results from the parametric analysis indicated that increasing the combustion air temperature, due to reduced exergy destruction in the burner and heat exchanger E-100, leads to a significant improvement in all performance indicators. Consequently, with this increase, the energy efficiency, exergy efficiency, electrical efficiency, and fuel saving rate were enhanced to 0.6269, 0.4587, 0. 4720, and 0.4288, respectively.