Cryogenic pressure temperature swing adsorption process for natural gas upgrade
March 5-10, 2017
The energy and chemical sectors are suffering remarkable changes. In this way, producing abundant quantity of energy with high quality, economic and environmental viability and sustainability is the main concern of the present times. One of such vital components of the world’s energy supply that fulfills the abovementioned requirements is natural gas .
Natural gas consists of 85–95% methane, but it also contains considerable amounts of heavier hydrocarbons as well as other compounds (CO2, N2, Hg, He, H2S) . In order to meet the pipeline quality standard specifications or Liquefied Natural Gas (LNG) production, impurities must be removed. Carbon dioxide is one of the major contaminants in natural gas, reducing its energy content and becoming acidic and corrosive in the presence of water, damaging pipelines and equipment. In LNG processing plants CO2 can solidify, blocking the pipeline systems and causing transportation drawbacks . In order to meet the pipeline quality standard specifications an upper limit for nitrogen and carbon dioxide of 4 and 2% is necessary, respectively. While, to inhibit the formation of dry ice in the liquefaction step, CO2 content must be reduced to 50 ppm level [2, 3].
Among the several separation technologies available for natural gas upgrade, such as chemical absorption, physical absorption, cryogenic distillation and membrane processes, adsorption processes are considered a competitive solution. Removal of carbon dioxide from natural gas for LNG production, can be carried out by cryogenic distillation using a multicolumn sequence to obtain a product stream with less than 50 ppm of CO2 . Cryogenic adsorption-based processes, particularly pressure thermal swing adsorption, arise as a reliable and innovative alternative to replace the distillation columns, in particular the last one.
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Mariana A. Moreira, Ana M. Ribeiro, Alexandre F.P. Ferreira, and Alírio E. Rodrigues, "Cryogenic pressure temperature swing adsorption process for natural gas upgrade" in "Separations Technology IX: New Frontiers in Media, Techniques, and Technologies", Kamalesh K. Sirkar, New Jersey Institute of Technology, USA Steven M. Crame, Rensselaer Polytechnic Institute, USA João G. Crespo, LAQV-Requimte, FCT-Universidade Nova de Lisboa, Caparica, Portugal Marco Mazzotti, ETH Zurich, Switzerland Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/separations_technology_ix/52