Dilute CO2 Research Articles

Dow to close pet plant in Pisticci, Italy

This paper evaluates the opportunities and associated costs for post-combustion capture at a world-scale complex refinery. It is concluded that it is technically feasible to apply post-combustion capture at such a refinery. The costs for capture and sequestration from a gasifier are calculated to be lowest at about 30 Euro per ton; this process currently already produces a concentrated CO2 stream. Next, the CO2 source most suited for capture appears to be a combined stack, but there are a number of other sources that may be targeted at comparable costs. In total these sources may form about 40% of the overall refinery emissions. Our evaluations show the costs of capture from such sources based on available amine technology will be in the range of 90–120 Euro per ton, which is about 3–4 times higher than the current carbon trading values. The capture of CO2 from a large amount of smaller CO2 sources will bring along even much higher costs. A high-level study of the CO2 emissions profile of a number of Shell refineries shows that, typically, up to 50% of the emitted CO2 may be captured at similar costs. About 10–20% of concentrated CO2 associated with hydrogen manufacturing may be captured at lower costs. The remainder of emitted dilute CO2 will bring along significantly higher costs. Based on this study, it is concluded for the justification of the implementation of post-combustion capture at refineries, either a significant increase in carbon trading values, mandatory regulations, or a major technological break-through is required.

Rapid 18O analysis of small water and CO2 samples using a continuous-flow isotope ratio mass spectrometer.

High-frequency throughput is often needed in isotopic studies in biological and medical fields. Here we report that high-precision oxygen isotope ratio measurements of water (+/-0.13 per thousand) were rapidly and routinely made on small samples (40-100 microL) using an isotope ratio mass spectrometer operated in continuous-flow mode. Simple modifications to existing instrumentation allow for rapid manual analyses of dilute CO2 (10% CO2/90% N2), including the addition of a septum port and water trap prior to the gas chromatography (GC) column (elemental analyzer column in this study) and the extension of fused-silica capillary tubing between the mass spectrometer source and the effluent tubing from the GC column (located within the CONFLO unit on Finnigan mass spectrometers). We routinely analyzed 20 small-volume samples per hour using this technique, without sacrificing precision of the oxygen isotope ratio measurement.

ABSORPTION AND DESORPTION OF CO2 BY AQUEOUS SOLUTIONS OF STERICALLY HINDERED 2-AMINO-2-METHYL-1-PROPANOL IN HYDROPHOBIC MICROPOROUS HOLLOW FIBER CONTAINED CONTACTORS

To understand the behavior of separation of CO2 from CO2-N2 mixtures using a hydrophobic microporous hollow fiber (polytetrafluoroethylene) contained gas-liquid contactor with aqueous solutions of 2-amino-2-methyl-l-propanol (AMP) as liquid media in the shell side, first, the absorption of dilute CO2 into aqueous AMP solutions and the desorption of CO2 from CO2-loaded AMP solutions into N2 stream were investigated separately for various combinations of operational variables. Secondly, the simultaneous absorption and desorption in a single unit was performed to check the possibility of a long-term continuous operation. The resistance to diffusion in the hollow fiber phase during absorption amounted to ca. 86% of the total resistance, and slightly decreased with increasing AMP concentration. The AMP solution partially leaks into pores of the hollow fiber, and both the diffusion and chemical reaction of dissolved CO2 in the liquid-filled pores under the slow-reaction regime mainly control the overall absorption rate. If the physical diffusion in the liquid-filled part of the pore completely controlled the absorption process in the present hollow fiber contactor, the length of the liquid-filled part would be evaluated to be 72 ˜ 108 urn as compared to the total pore length of 500 um. The desorption rate was found to be independent of the gas velocity in the lumen side. The desorption process can be regarded as being controlled by diffusion and chemical reaction in both the stagnant film of the liquid phase and the liquid-filled pore of the hollow fiber phase under the slow or intermediate reaction regime. Simultaneous absorption and desorption process in a single contactor was found to be kept in a stable state at least until 20 h.

CO2 Coordination to Nickel Atoms: Matrix Isolation and Density Functional Studies

The interaction of the CO2 molecule with nickel atoms was studied by using matrix isolation spectroscopy and density functional theory. In argon dilute matrices, no reaction occurs, even after annealing the deposit. In neat CO2 matrices, it is shown that carbon dioxide forms a 1:1 complex with nickel which is characterized by its UV−visible and FTIR absorptions, including isotopically labeled species. Theory predicts the side-on coordination mode to be the most stable. The binding energy of the side-on Ni(CO2) complex is estimated to be 18 kcal/mol. The calculated OCO angle is 145°, which is quite a large value compared to those encountered in other known CO2 complexes. In dinitrogen matrices, the yield of CO2 complexation is considerably enhanced relative to that in argon dilute and neat CO2 matrices, which is attributed to the formation of unsaturated Ni(N2)n complexes prior to CO2 coordination. The CO2 binding energies calculated for the Ni(CO2)(N2)n (n = 1, 2) complexes (respectively 32 and 4 kcal/mol...

Photosynthetic carbon metabolism in Euglena gracilis. Part XXIII. Effects of photosynthetic intermediates on the activation state of ribulose 1,5-bisphosphate carboxylase/oxygenase from Euglena gracilis Z.

The half-saturating concentration of ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) from Euglena gracilis Z for CO2 in its activation by CO2 in the presence of a saturating concentration of MgCl2 (Ka) was measured by analyzing the partial reversible inactivation of the fully activated enzyme in the medium with dilute CO2. The Ka of the Euglena enzyme was 12.5 μM. The Ka values were 6.3 μM for the enzyme from soybean, 10.8 μM from maize, 23.3 μM from Scenedesmus obliquus, and 20.8 μM from Anabaena 7120. The activated state of Euglena RuBisCO was stabilized by 6-phosphogluconate, fructose 1, 6-bisphosphate, and 3-phosphoglycerate in the medium containing low concentrations of CO2. Both fructose 6-phosphate and ATP stimulated inactivation in the medium. NADPH not only stabilized the activated state of the enzyme, but also enhanced the enzyme activity over the full activity measured in the absence of NADPH. NADP+ did not nullify the effects of NADPH on the activation at all. The physiological significance of the effects of these photosynthetic metabolites on the activated state of Euglena RuBisCO is discussed.

Pressure effect on the Curie temperature in dilute ferromagnetic alloys

The pressure dependence of the Curie temperature dTC/dP in dilute transition metal alloys and rare earth Co2 compounds is calculated in the combined model of localised spins and itinerant d electrons. It is found that dTC/dP varies as -TC at low TC and this result agrees qualitatively with many experimental results in dilute transition metal alloys. The calculated values of d ln TC/d ln V for Pd-Fe, Pd-Co, Pd-Ni, Pt-Fe and Pt-Co alloys and for the GdCo2 compound are compared with the experimental results. The calculated values of d ln TC/d ln V for Pd-Fe alloys agree well with the experimental values, which show a maximum at about 60K. The calculated results predict that there also exists a maximum in the experimental values of d ln TC/d ln V for (Gd-Y)Co2 compounds and Pd-Co alloys.

Synthetic carbonaceous fuels and feedstocks from oxides of carbon and nuclear power

A study has been made on converting alternative sources of oxides of carbon (CO and CO2) to synthetic methanol with nuclear-power-generated electrolytic hydrogen and oxygen. The sources of CO and CO2 include 1.(1) the oxygen-blown blast furnace which produces CO as a by-product from hot-metal production,2.(2) the steam calcination of limestone which products CO2 as a by-product of the lime and cement industry,3.(3) fossil-fuel power plant stack-gas as a source of CO2, and4.(4) the atmosphere, from which CO2 is recovered in a novel carbonate electrolytic cell. The recovered CO or CO2 is catalytically combined with electrolytic H2 to produce the synthetic fuels. In these systems, the conservation, efficiency, and environmental control of coal utilization is significantly improved. Blast-furnace CO could supply up to 20% of the gasoline demand in the USA at a 1985 cost of 56 to 60cent/US gallon, breaking even with $19/Bbl imported oil. The CO2 from steam calcination of limestone could supply about 9% of the gasoline demand and the recovered CO2 from only 60% of the coal-fired power plants in the country could supply all of today’s gasoline demand in the country (≈1011 US gal/yr). The 1985 cost estimates for carbon-dioxide-based gasoline range from 68¢/US gal for the highly concentrated calciner-CO2 feedstream to 83¢/gal for the very dilute atmospheric CO2 feed, breaking even with $21 to $28/barrel oil for conventional gasoline. The dominating cost factor is the electrical power cost from the nuclear plant. The sharing of peaking and base-load costs between the power and synthetic-fuels consumers offers a cost and energy effective system.

Charge Exchange of Fast Iodine Ions in a Dense Jet of Carbon Dioxide

Charge distribution measurements were made with 10-75 MeV iodine ions of various incident charge states traversing either a supersonic CO2-jet of variable density in the range 5 x 1014 to 1.5 x 1017 molecules/cm3 or a target of dilute CO2 with a maximum density of 5 x 1014 molecules/cm3. The equilibrium mean charge ts of the iodine ions in the jet is found to be higher than in the dilute gas. The maximum difference of about one charge unit is observed at 75 MeV. Ihere is no indication for a further increase of Lat gas densities above 5 x 1016 molecules/cm3. Cross sections for electron capture and loss were determined by means of a least-squares-evaluation of non-equilibrium charge distributions. Considerable decrease of the capture cross sections for some lower charge states has proved to be responsible for the increase ?, whereas the loss cross sections do not change measurably with increasing target density.

Polarized Crystal Spectra of CoF2 and Co0.06Zn0.94F2

Polarized spectra of oriented single-crystal CoF2 and Co0.06Zn0.94F2 are presented in the range 5000–25 000 cm−1 at 298, 77, and 20.4°K. Molar extinction coefficients and oscillator strengths are calculated. The spectra of CoF2 and of dilute Co2+ in ZnF2 are very similar. The principal bands are identified as transitions from the T1g4 (4F) ground level to T2g4 (4F), A2g4 (4F), and T1g4 (4P) levels. A value of Dq = 715 cm−1 is obtained. A sharp electric dipole line, 10 cm−1 wide, is seen at 22 768 cm−1 in CoF2 at 20.4°K.