Etanolaminas

Korean J. Chem. Eng., 26(6), 1504-1511 (2009) DOI: 10.1007/s11814-009-0254-z

RAPID COMMUNICATION

Simulation and optimization of ethanol amine production plant
Gholamreza Zahedi*,†, Saeideh Amraei**, and Mazda Biglari***
*Process Systems Engineering Centre (PROSPECT), Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor Bahru, Johor,Malaysia **Simulation and Artificial Intelligence Research Center, Chemical Engineering, Department, Razi University, Iran ***Department of Chemical Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3 (Received 6 April 2009 • accepted 7 April 2009)
Abstract−An industrial Ethanol Amine (EA) production plant was simulated and optimized. Due to lack of accurate reaction rateinformation, the first step involved obtaining reliable kinetic data from the SRI (Stanford Research Institute) industrial database and calculation using error minimization method. In the next step, by implementing the obtained reaction kinetics the whole plant was simulated using Hysys software. Simulation results were compared with the SRI data and showed that there is acceptable agreement betweensimulation and the measured industrial data. In the next step of study by applying the gradient search (GS) optimization technique the plant was optimized using: feeding ammonia to ethylene oxide (EO) molar ratio, water flow rate in the feed stream, and reactor temperature as optimization variables. Employing process profit as objective function the optimal operating conditions were found to be: ammoniato EO ratio of 5 (mol/mol), water flow rate of 52.59 kg mol/hr and reactor temperature of 85 oC. Key words: Simulation, Optimization, Ethanol Amine Production, Ethylene Oxide, Ammonia

INTRODUCTION Regarding the broad application of Ethanol Amine (EA), its production is of great interest to the petrochemical industry. The industrial production of EA was accomplished in 1930 followed by thelarge-scale production in 1945, when alkoxylation with ethylene oxide (EO) and propylene oxide was replaced by chlorohydrins [1,2]. The commercial importance of EA increased from 1970, when industrial production of EO began. The modern industrial production of EA is operated exclusively by reaction of EO and excess amount of ammonia in presence of water [3]. It has been proved that a small amount ofwater is necessary to promote reaction. When there is not any water in the system, EO does not react with ammonia. In fact, water plays a catalytic role in the corresponding reactions [2,4]. Based on operational conditions monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) are produced through three parallel-consecutive competitive reactions [1]. EAs react with a large number ofcompounds such as ammonia, carbon dioxide, sulfuric acid, sodium hydroxide, carbon disulfide, thionyl chloride and also with acids and aromatic aldehydes [4-6]. In general, they are very desirable as H2S and CO2 absorbents for natural gas treatment [7]. Because of alcoholic characteristics, MEA and DEA have broader industrial applications. On the other hand, DEA and TEA are used in makingdetergents, textiles, pharmaceuticals, emulsifiers in drilling and excavation of oil wells, corrosion inhibitors as well as additives to cement [2]. EAs are hygroscopic, colorless and viscous liquids at room temperature. TEA boils at 27 oC, whereas the other two EAs have higher boiling points. Their densities are slightly greater than water den†

sity and have ammonia-like odor. The EA freezing pointis considerably decreased by adding water. MEA and DEA are soluble, with any proportion, in water and alcohol but considerably less in ether. All amines form white crystalline solids when freeze [7]. Very few quantitative studies have been conducted for EA synthesis. One source is the study conducted by Japanese researchers [8], yet the lack of confirmed data renders it unsuitable to construct...