بررسي آزمايشگاهي و مدل سازي حذف CO2 از گاز طبيعي با استفاده از شبكه آلي- فلزي نانو جاذب هاي Cu-BTC

چكيده انگليسي :

Experimental Study and Modeling of CO Removal from Natural Gas by using Metal Organic Framework of Cu BTC Nano Adsorbents Tahereh Asadi t asadi@ce iut ac ir Department of Chemical Engineering Isfahan University of Technology Isfahan Iran Degree Ph D Language Farsi upervisor M R Ehsani Ehsanimr@cc iut ac ir S Abstract Natural gas contains a large quantity of methane typically to with heavier hydrocarbons such as ethane propane isobutane and normal butane It has also nitrogen and carbon dioxide as minor impurities Before reaching the customer natural gas has to pass several processing steps These steps are partly necessary to be able to transport the gas over long distances and partly necessary for the recovery of valuable components contained in the gas Removal of CO from the natural gas may be required in order to meet pipeline standards and prevent corrosion To meet pipeline quality methane the maximum amount Carbon Dioxide cannot exceed Adsorption is one of the attractive methods for the separation of CO from natural gas So in this work experimental and modeling study of CO adsorption for methane purification using metal organic framework of Cu BTC powder and tablet nano adsorbent were performed The first requirement in the design of any adsorption process is to determine the equilibrium of adsorption of the pure components With this purpose single gas equilibrium adsorption data for carbon dioxide and methane adsorption on nanoporous metal organic framework Cu BTC powder and tablets were measured in a magnetic suspension balance in the temperature range K and pressure range bar and fitted with Langmuir model The tablets adsorption loading is mol kg for methane and mol kg for carbon dioxide at bar and K while these values are and mol kg for powder in the same conditions Isosteric heats of adsorption were and kJ mol for carbon dioxide and methane respectively on both adsorbents which indicates a strong adsorption of carbon dioxide In the next step the diffusion coefficients of carbon dioxide and methane on Cu BTC adsorbent were studied by ZLC technique in one temperature K three different flow rates and one concentration of CO or CH balanced in He The results showed that the gas desorbs from the pores of adsorbent very fast and so intra particle diffusion is so fast that always there is a uniform concentration inside adsorbent and the concentration curve versus time are independent of diffusion coefficients and only is a function of flow rate and mass transfer coefficient So it was concluded that the process is controlled by external mass transfer and the diffusivity coefficients cannot be estimated using the ZLC curves Finally using one column of the PSA unit filled with Cu BTC tablets carbon dioxide and methane single component breakthrough curves were obtained by feeding the corresponding gas to the adsorbent bed initially filled with helium at bar and K Also a complete mathematical model that describes the dynamic behavior of multicomponent adsorption in a fixed bed composed of material momentum and energy balances was used in the simulation of breakthrough curves and solved in gPROMS environment Process System Enterprise London UK using the orthogonal collocation on finite elements as the numerical method A good agreement was observed between the experimental data and the predicted molar fraction and temperature histories by this model So the preferential adsorption capacity of CO on nanoporous Cu BTC metal organic framework and binary breakthrough curves confirmed that this material can be used for methane purification from natural gas by adsorption process PDF created with pdfFactory trial version www pdffactory com

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بررسي آزمايشگاهي و مدل سازي حذف CO2 از گاز طبيعي با استفاده از شبكه آلي- فلزي نانو جاذب هاي Cu-BTC