Separation of carbon dioxide,

FoUowiag Monsanto s success, several companies produced membrane systems to treat natural gas streams, particularly the separation of carbon dioxide from methane. The goal is to produce a stream containing less than 2% carbon dioxide to be sent to the national pipeline and a permeate enriched ia carbon dioxide to be flared or reinjected into the ground. CeUulose acetate is the most widely used membrane material for this separation, but because its carbon dioxide—methane selectivity is only 15—20, two-stage systems are often required to achieve a sufficient separation. The membrane process is generally best suited to relatively small streams, but the economics have slowly improved over the years and more than 100 natural gas treatment plants have been installed. 

In gas separation with membranes, a gas mixture at an elevated pressure is passed across the surface of a membrane that is selectively permeable to one component of the mixture. The basic process is illustrated in Figure 16.4. Major current applications of gas separation membranes include the separation of hydrogen from nitrogen, argon and methane in ammonia plants the production of nitrogen from ah and the separation of carbon dioxide from methane in natural gas operations. Membrane gas separation is an area of considerable research interest and the number of applications is expanding rapidly. 

Pex, P.P.A.C. and Y.C. van Delft, Silica membranes for hydrogen fuel production by membrane water gas shift reaction and development of a mathematical model for a membrane reactor, in Carbon Dioxide Capture for Storage in Deep Geologic Formations—Results from the C02 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources, eds., D. Thomas, and B. Sally, Vol. 1, Chapter 17, 2005. 

The million-fold difference in rates for the C-C bond-breaking step in model decarboxylation reactions for thiamin systems and their very similar enzyme intermediates might be understood in terms of the enzyme being able to overcome the reverse reaction with great efficiency. Since the reaction occurs within an active site, where proton donors and/or electron acceptors are available without diffusion to quench the carbanion, separation of carbon dioxide can be more efficient. This increases the overall throughput, increasing the observed rate of the reaction. 

Hodges, C. T., Matson, R. F. Gas chromatographic separation of carbon dioxide, carbonyl sulphide, hydrogen sulphide, carbon disulphide and sulphur dioxide. Anal. 

Thomsberra, W. L. Isothermal gas chromatographic separation of carbon dioxide, carbon sulfide, hydrogen sulfide, carbon disulfide and sulfur dioxide. Anal. Chem. 

Techniques of this type guarantee rapid, nearly complete absorption, not only of hydrogen sulfide, but also of CO , alone or mixed with H S. They arc unaffected by variations io partial pressure of the acid components, and are accordingly better adapted to installations operating at low pressure and requiring the separation of carbon dioxide up to very low contents. 

Separation of carbon dioxide and hydrocarbons by inorganic membranes... 

Kusakabe, K., and S. Morooka, 1994, Preparation of pcrovskitc-typc oxide membrane for separation of carbon dioxide at high temperature, presented at 3rd InL Conf. Inorg. Membr., Worcester, MA, USA. 

Quinn R, Appleby JB, and Fez GP. New facilitated transport membraness for the separation of carbon dioxide from hydrogen and methane. J. Membr. Sci. 1995 104 139-146. 

Kusakabe K, Kuroda T, and Morooka S. Separation of carbon dioxide from nitrogen using ion-exchanged faujasite-type zeolite membranes formed on porous support tubes. J Membr Sci 1998 148(l) 13-23. 

Falk-Pedersen O and Dannstrom H. Separation of carbon dioxide from offshore gas turbine exhaust. Energ. Convers. Manag. 1997 38 S81-S86. 

Bolland, O., Kvamsdal, H.M, and Boden, J.C. A comparison of the efficiencies of the oxy-fuel power cycles water cycle, Graz cycle and Matiant cycle. In Carbon Dioxide Capture for Storage in Deep Geological Formations—Results from the C02 Capture Project. Capture and Separation of Carbon Dioxide from Combustion Sources (ed. D.C. Thomas), Vol. 1. Amsterdam Elsevier, p. 499-511, 2005. 

In this section, the major developments regarding the separation of carbon dioxide from other gases, such as H2, O2, CO, N2, and CH4, using mobile carrier systems are reported. 

Myers C, Pennline H, Luebke D, llconichb J, Dixon JK, Maginn EJ, Brennecke JF (2008) High temperature separation of carbon dioxide/hydrogen mixtures using facilitated supported ionic liquid membranes. J Membr Sci 322 28-31... 

Hu, Q. Klugee, R. 2005 f. Am. Chem. Soc. 127, 12242-12243 Making thiamin work faster acid-promoted separation of carbon dioxide. 

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