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Thermopervaporation for regeneration of triethylene glycol (TEG):Experimental and model development

Dalane, Kristin, Josefsen, Natalie Therese, Ansaloni, Luca, Hillestad, Magne, Deng, Liyuan
Journal of membrane science 2019 v.588 pp. 117205
air, artificial membranes, distillation, ecological footprint, energy use and consumption, liquids, mathematical models, natural gas, oil and gas industry, oils, permeability, pervaporation, temperature, triethylene glycol
Subsea processing is getting increased interest in the oil and gas sector as it can provide broader exploration of the oil and gas with a lower environmental footprint. Dehydration of natural gas with the use of triethylene glycol (TEG) is one of the main processing step for natural gas treatment to avoid transportation problems caused by the presence of water. Distillation is a commonly used technology for topside regeneration of TEG. However, for subsea operation alternative technologies are required to avoid complexity and the large energy consumption. Membranes are evaluated as promising solutions as they fulfil the subsea design criteria of compact design, flexible operation, and high modularity. In this work, the use of thermopervaporation for regeneration of TEG has been assessed. A mathematical model of a plate-and-frame thermopervaporation membrane module has been developed, where two-dimensional flow are considered for the liquid phases and the air gap is treated as a stagnant phase. Experimental pervaporation data were provided for the tuning of the model and the development of a temperature dependent permeability correlation. In addition, the effects of operation conditions and membrane properties on the separation performance were investigated. From this evaluation, it is clearly shown that the air gap significantly affects the separation performance and is a key parameter in the design of the thermopervaporation module.