Natural Gas Dehydration by Absorption Process: A comparative simulation study towards high effective natural gas dehydration using TEG technology

Natural gas dehydration by absorption using triethylene glycol (TEG) is one of the most effective techniques with high efficiency. There are many processes using this approach but any of them is able to combine the high performance and the economic energy consumption. In this study water hydrocarbon phase behavior was determined for different gas dehydration unit. The effects of the operating conditions of the gas dehydration unit in determining the outlet gas dew point and water content remaining in dry gas were studied by means of simulation run using ASPEN HYSYS software. DRIZO process showed the most significant change of water dew point curve followed by conventional stripping gas dehydration process and then the typical gas dehydration process. At the other hand, study was done on improving the absorption capacity of TEG as the water absorbent by adding additives to the absorbent. Lastly, comparisons between theoretical and simulation results are justified to determine whether it shows a good validation of the results to meet the requirements of current industry practices

Evaluation of Chemically Modified Mono-Ethylene Glycol as a Potential Solvent for Enhanced Natural Gas Dehydration Process

Natural gas dehydration using glycol absorption process is one of the gaseous phase water removal technique which is efficient and cost effective. Glycols used for the absorption ranging from mono-ethylene glycol, di-ethylene glycol , tri-ethylene glycol to tetra-ethylene glycol in which tri-ethylene glycol is widely used due to its high dehydration performance. However, many industries in Malaysia that used this approach rarely able to combine high performance, economic energy consumption and low environmental emission. The main problem with the usage of tri-ethylene glycol is BTEX emission, which BTEX are classified as carcinogenic chemicals and are considered as air toxin. Besides, the non-availability of tri-ethylene glycol locally in Malaysia increases the cost of dehydration. Therefore, the locally produced mono-ethylene glycol by OPTIMAL Glycols (M) Sdn. Bhd. with a production of 365000 MTPA make it an attractive candidate. In this study, chemically modified mono-ethylene glycol is used as a new solvent to replace tri-ethylene glycol. The objectives are to simulate different natural gas dehydration processes using mono-ethylene glycol as new solvent, to validate and optimize the simulation besides to investigate enhancement of the dehydration process through chemical modification of mono-ethylene glycol. The scope of study includes comparing the chemically modified mono-ethylene glycol with tri-ethylene glycol in terms of performances; for example, the outlet natural gas water content and BETX emission. The data and results are obtained by process modeling using Aspen HYSYS 8.4 (latest) simulation software

Model of the expansion process for R245fa in an Organic Rankine Cycle (ORC)

An Organic Rankine Cycle (ORC) is considered as one of the most environmental-friendly ways to convert different kinds of low temperature energies, i.e. solar, geothermal, biomass and thermal energy of exhaust gases into electrical energy. Two important facts about the ORC must be considered: An organic fluid is selected as the working fluid and a high expansion ratio is usually presented in the machinery due to thermodynamic and efficiency factors. In the past, the pre-design of turbomachinery has been based on the usage of ideal fluid laws, but the real gas effects have a significant influence in the ORC working condition, due to its proximity to the saturation vapor line. In this article, the Equations of State (EoS) (Ideal gas, Redlich-Kwong-Soave and Peng-Robinson) have been evaluated in a typical ORC expansion in order to observe the inaccuracies of the ideal gas model with different thermodynamic variables. Finally an isothermal process followed by an isochoric process is proposed to reproduce the thermodynamic process of the organic fluid expansion by means of simpler equations. In the last point of this paper, several examples of this expansion process have been calculated, in order to analyze the proposed methodologies. It has been concluded that in typical expansion process of ORC (2.5 MPa-0.1 MPa and 1.6MPa-0.1MPa), the PR and RKS equations show deviations between 6% and 8% in specific energy. These deviations are very low compared with the ideal gas equation whose deviations are above 100 %.This work was partially funded by the "Programa de Formacion de Profesorado Universitario (F.P.U)", "Programa de Apoyo a la Investigacion y Desarrollo de la Universidad Politecnica de Valencia 2010", "Proyectos I+D para grupos de investigacion emergentes 2011" and "Programa de apoyo a la investigacion y desarrollo de la U.P.V (PAID-06-09)". The authors thanks to R. Gatzweiler for his help to improve the English grammar.Lujan Martinez, JM.; Serrano Cruz, JR.; Dolz Ruiz, V.; Sánchez Serrano, J. (2012). Model of the expansion process for R245fa in an Organic Rankine Cycle (ORC). Applied Thermal Engineering. 40:248-257. https://doi.org/10.1016/j.applthermaleng.2012.02.020S2482574

Evaluation of Chemically Modified Mono-Ethylene Glycol as a Potential Solvent for Enhanced Natural Gas Dehydration Process

Natural gas dehydration using glycol absorption process is one of the gaseous phase water removal technique which is efficient and cost effective. Glycols used for the absorption ranging from mono-ethylene glycol, di-ethylene glycol , tri-ethylene glycol to tetra-ethylene glycol in which tri-ethylene glycol is widely used due to its high dehydration performance. However, many industries in Malaysia that used this approach rarely able to combine high performance, economic energy consumption and low environmental emission. The main problem with the usage of tri-ethylene glycol is BTEX emission, which BTEX are classified as carcinogenic chemicals and are considered as air toxin. Besides, the non-availability of tri-ethylene glycol locally in Malaysia increases the cost of dehydration. Therefore, the locally produced mono-ethylene glycol by OPTIMAL Glycols (M) Sdn. Bhd. with a production of 365000 MTPA make it an attractive candidate. In this study, chemically modified mono-ethylene glycol is used as a new solvent to replace tri-ethylene glycol. The objectives are to simulate different natural gas dehydration processes using mono-ethylene glycol as new solvent, to validate and optimize the simulation besides to investigate enhancement of the dehydration process through chemical modification of mono-ethylene glycol. The scope of study includes comparing the chemically modified mono-ethylene glycol with tri-ethylene glycol in terms of performances; for example, the outlet natural gas water content and BETX emission. The data and results are obtained by process modeling using Aspen HYSYS 8.4 (latest) simulation software