Hajilary Nasibeh, Rezakazemi Mashallah
Department of Chemical Engineering, Faculty of Engineering, Golestan University, Gorgan, Iran.
Faculty of Chemical and Materials Engineering, Shahrood University of Technology, Shahrood, Iran.
Chem Cent J. 2018 Nov 23;12(1):120. doi: 10.1186/s13065-018-0493-3.
The gas sweetening unit of phase 2 and 3 in South Pars Gas Field (Asalouyeh, Iran) was first simulated to investigate the effect of mono ethylene glycol (MEG) in the amine loop. MEG is commonly injected into the system to avoid hydrate formation while a few amounts of MEG is usually transferred to amine gas sweetening plant. This paper aims to address the points where MEG has negative effects on gas sweetening process and what the practical ways to reduce its effect are. The results showed that in the presence of 25% of MEG in amine loop, HS absorption from the sour gas was increased from 1.09 to 3.78 ppm. Also, the reboiler temperature of the regenerator (from 129 to 135 °C), amine degradation and required steam and consequently corrosion (1.10 to 17.20 mpy) were increased. The energy consumption and the amount of amine make-up increase with increasing MEG loading in amine loop. In addition, due to increasing benzene, toluene, ethylbenzene and xylene (BTEX) and heavy hydrocarbon solubility in amine solution, foaming problems were observed. Furthermore, side effects of MEG presence in sulfur recovery unit (SRU) such as more transferring BTEX to SRU and catalyst deactivation were also investigated. The use of total and/or partial fresh MDEA, install insulation and coating on the area with the high potential of corrosion, optimization of operational parameters and reduction of MEG from the source were carried out to solve the problem. The simulated results were in good agreement with industrial findings. From the simulation, it was found that the problem issued by MEG has less effect when MEG concentration in lean amine loop was kept less than 15% (as such observed in the industrial plant). Furthermore, the allowable limit, source and effects of each contaminant in amine gas sweetening were illustrated.
对伊朗阿萨卢耶南帕尔斯气田2期和3期的气体脱硫装置进行了首次模拟，以研究单乙二醇（MEG）在胺回路中的影响。通常向系统中注入MEG以避免水合物形成，而少量MEG通常会转移到胺法气体脱硫装置中。本文旨在探讨MEG对气体脱硫过程产生负面影响的关键点以及降低其影响的实际方法。结果表明，当胺回路中存在25%的MEG时，酸性气体中H₂S的吸收量从1.09 ppm增加到3.78 ppm。此外，再生器的再沸器温度（从129℃升至135℃）、胺降解以及所需蒸汽量，进而腐蚀（从1.10 mpy增至17.20 mpy）均有所增加。随着胺回路中MEG负荷的增加，能耗和胺补充量也会增加。此外，由于胺溶液中苯、甲苯、乙苯和二甲苯（BTEX）以及重烃溶解度的增加，出现了发泡问题。此外，还研究了MEG在硫磺回收装置（SRU）中的副作用，如更多的BTEX转移到SRU以及催化剂失活。为解决该问题，采取了使用全部和/或部分新鲜MDEA、在高腐蚀风险区域安装隔热材料和涂层、优化操作参数以及从源头减少MEG等措施。模拟结果与工业实际结果吻合良好。通过模拟发现，当贫胺回路中MEG浓度保持低于15%时（如工业装置中所观察到的），MEG引发的问题影响较小。此外，还阐述了胺法气体脱硫中每种污染物的允许限度、来源及影响。
