Simulation and Optimization of the Acid Gas Absorption Process by an Aqueous Diethanolamine Solution in a Natural Gas Sweetening Unit

Abstract

The presence of carbon dioxide in natural gases can lower the quality of natural gas and can cause CO 2 freezing problems. Therefore, using reliable techniques for the reduction and elimination of carbon dioxide from natural gases is necessary. The aqueous diethanol amine (DEA) solution’s ability to simultaneously absorb H 2 S and CO 2 from sour natural gases makes it possible to use this solution in the natural gas sweetening process. The goal of this work was to determine the maximum amount of the removed CO 2 by an aqueous DEA solution in one of the gas sweetening plants of the National Iranian South Oilfields Company (NISOC). For this purpose, based on the obtained designed experiment results using the L9 orthogonal array Taguchi method, the experiments were conducted and three levels of amine concentrations (25, 28, and 30 wt %), temperatures (40, 50, and 60 °C), and circulation rates of lean amine (220, 240, and 260 m 3 h –1 ) were considered as the key operational parameters on CO 2 removal. To evaluate the ability of the HYSYS simulation software and the Kent–Eisenberg thermodynamic model to predict CO 2 absorption by an aqueous DEA solution in the gas sweetening process, the field data were compared with the results of the simulation. It was observed that the maximum removal of CO 2 is achieved at a lean amine concentration of 30 wt %, a temperature of 40 °C, and a circulation rate of 260 m 3 h –1 . Also, the experimental results indicate that the effects of the selected process variables on CO 2 absorption are not linear and the most effective parameter on carbon dioxide removal is the concentration of amine in an aqueous solution and the temperature of the lean amine has the least effect. Besides, the obtained simulation results are in the range of the unit design basis but have some deviations from field data. The findings of this study can help in better understanding of the selection of the effective variables in the natural gas sweetening process and obtaining their appropriate values to achieve the highest efficiency.

Comparison of DEA and TEA performance for CO2 capture from synthesis gas of ammonia under different operational conditions

“…The simulation model of the acid gas removal process was successfully created, and the process flow diagram of the plant is presented in figure [2]& [3]. However, this study aimed to study the influence of using DEA &TEA amine on the efficiency of the acid gas removal process, by considering several variables.…”

“…Figure 3. Schematic of co2 capture process using TEA solvent As shown in table [2], different solvent amines were used to improve the performance of the acid gas removal process while maintaining the same operating conditions. As a result, a few process parameters loading will be recorded and discussed, such as CO2 in treated gas, CO2 stripping to atmosphere, Amines and Energy requirements, and so on.…”

“…It is the primary focus of this paper. The simulation results of acid gas removal in software programme Figure [2][3] are shown in tables [3] & [4]. by employing two solvent types, di ethanolamine and tri ethanolamine The CO2 capture in the case of DEA is greater than in the case of TEA, as shown in tables [3] and [4].…”

“…Fossil fuels currently meet approximately 85 percent of the world's commercial energy needs, and anthropogenic greenhouse gas emissions to the atmosphere are expected to cause significant global climate change. [1], [2] CO2 is the most significant anthropogenic greenhouse gas, resulting primarily from the use of fossil fuels and many industries. As a result, the development of a good CO2 capture technology is critical.…”

“…The goal of these various investigations is to figure out which solvent is best for removing CO2 from synthesis gas under various conditions and to construct a recovery plant with the best state. [2] Each analysis has been performed for different SOLVENT RATE for CO2 Capture in the synthesis gas of AMMONIA production [1], [3]…”