The potential for the metal organic framework (MOF) Cu-BTC to selectively adsorb and separate CO 2 is considered. Isotherms for CO 2 , CH 4 , and N 2 were measured from 0 to 15 bar and at temperatures between 25 and 105 °C. The isotherms suggest a much higher working capacity (×4) for CO 2 adsorption on Cu-BTC relative to the benchmark zeolite 13X over the same pressure range. Higher CO 2 /N 2 and CO 2 /CH 4 selectivities in the higher pressure range (1-15 bar) and with lower heats of adsorption were also demonstrated. Cu-BTC was observed to be stable in O 2 at 25 °C, but its crystallinity was reduced in humid environments. The CO 2 adsorption capacity was progressively reduced upon cyclic exposure to water vapor at low relative humidity (<30%), but leveled out at 75% of its original value after several water adsorption/desorption cycles.

Capture of CO 2 from flue gas streams using adsorption processes must deal with the prospect of high humidity streams containing bulk CO 2 as well as other impurities such as SO x , NO x , etc. Most studies to date have ignored this aspect of CO 2 capture. In this study, we have experimentally examined the capture of CO 2 from a 12% synthetic flue gas stream at a relative humidity of 95% at 30°C. A 13X adsorbent was used and the migration of the water and its subsequent impact on capture performance was evaluated. Binary breakthrough of CO 2 /water vapor was performed and indicated a significant effect of water on CO 2 adsorption capacity, as expected. Cyclic experiments indicate that the water zone migrates a quarter of the way into the column and stabilizes its position so that CO 2 capture is still possible although decreased. The formation of a water zone creates a "cold spot" which has implications for the system performance. The recovery of CO 2 dropped from 78.5% to 60% when moving from dry to wet flue gas while the productivity dropped by 22%. Although the concentration of water leaving the bed under vacuum was 27%(vol), the low vacuum pressure prevented condensation of water in this stream. However, the vacuum pump acted as a condenser and separator to remove bulk water. An important consequence of the presence of a water zone was to elevate the vacuum level thereby reducing CO 2 working capacity. Thus although there is a detrimental effect of water on CO 2 capture, long term recovery of CO 2 is still possible in a single VSA process. Pre-drying of the flue gas steam is not required. However, careful consideration of the impact of water and accommodation thereof must be made particularly when the feed stream temperature increases resulting in higher feed water concentration.

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The reactions of a strain of marine alga Chlorococcum sp. and of a polystrain containing a mixture of marine algae with CO/H 2 O have been studied. The yields and chemical composition of the products obtained from the reactions with CO/ H 2 O were compared with those using N 2 and H 2 . The effects of selected potential catalysts (Na 2 CO 3 , NaAlO 2 , and Fe) and the water-to-algae ratio on the product yields and composition when the reactions were carried out under CO/H 2 O are also described. Both algae gave high product yields at 285 °C, but the quality of the product as a liquid fuel increased at higher temperature. The reactions with CO/H 2 O tended to give higher oil yields and higher-quality products (lower nitrogen, higher atomic H/C ratio) than those using H 2 or N 2 and, in addition, reduced the amount of dewatering of the algae that is required.