Chemical Recovery Processes of CO2

2021 ◽  
Vol 25 (12) ◽  
pp. 30-37
Author(s):  
L.G. Pinaeva ◽  
A.S. Noskov

Existing (production of urea, dimethyl carbonate, polypropylene carbonate) and promising (production of methanol, synthesis gas, monomers dedicated to synthesis of polyurethanes and polycarbonate) chemical technologies which any, time soon, may become CO2 based economy for producing motor fuels and basic chemicals have been overviewed. Based on estimates of CO2 removals in these processes, it has been concluded that there is a potential for developing technologies to produce methanol from CO2 to a competitive cost of the target product. It is expected that interest in this process will decrease if stable carbon dioxide conversion catalysts for methane are introduced into the market.

Author(s):  
Zhanar Kudyarova ◽  
Anatoly Mironenko ◽  
Asel Kazieva ◽  
V. Аntonuk ◽  
Zulkhair Mansurov

The application field of materials based on lanthanum orthophosphate (LaPO4) including nanomaterials, has been permanently extending recently. The high level of mechanical properties and the compatibility with numerous oxides make it possible to consider the possibility of using lanthanum orthophosphate as a composite material for construction purposes. This application is particularly promising when nanoparticles with quasi-1D morphology (nanorods) are used. The high isomorphic capacity of the LaPO4-based phase for alkaline-earth ions and ions of lanthanides and actinides, high chemical stability, and high radiation hardness make promising the application of this compound as a matrix for immobilization of radioactive wastes. The possibility of obtaining lanthanum phosphate (LaPO4) by the hydrothermal method is considered in the work. Effects of pH, temperature and time of processing of hydrothermal synthesis on the morphology and structure of monostructured lanthanum phosphate are studied. It has been established that, with the increase of pH, the morphology of phosphate changed, the size of the crystallites increased, while the crystal structure changed from hexagonal to monoclinic. The catalytic activity of nanostructured low-percentage Mg-Ni-Co-catalysts based on high-temperature KT-11-TO grade fiberglass obtained by “solution combustion” (SC) method was studied at carbon dioxide conversion of methane (CDCM). The physico-chemical characteristics of samples were studied using X-ray diffraction phase analysis, temperature-programmed reduction (TPR) and transmission electron microscopy (TEM). The X-ray phase method showed the formation of several phases during the synthesis: NiCo2O4, 3CoO·5NiO, MgO, and Co3O4. According to TEM, active catalyst particles have a size of 5-10 nm proving the nanoscale size of the active component. TPR method showed the shift of maximum hydrogen absorption to higher temperatures. Apparently, it occurs due to the interaction of the active components with the carrier till the new phase formation. On the basis of the gas chromatographic analysis the high activity of fiberglass catalysts at the carbon dioxide conversion of methane into synthesis gas with a conversion of the initial components close to ~ 100% was disclosed. The optimal technological conditions for the CDCM process were established – a temperature in the range of 850-900°С, the volumetric rate of initial reactants 4000-10000 h-1 with a ratio of methane to carbon dioxide equal to 1.


2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Eric R. Morgan ◽  
Thomas L. Acker

A methanol synthesis unit (MSU) that directly converts carbon dioxide and hydrogen into methanol and water was developed and tested. The MSU consists of: a high-pressure side that includes a compressor, a reactor, and a throttling valve; and a low-pressure side that includes a knockout drum, and a mixer where fresh gas enters the system. Methanol and water are produced at high pressure in the reactor and then exit the system under low pressure and temperature in the knockout drum. The remaining, unreacted recycle gas that leaves the knockout drum is mixed with fresh synthesis gas before being sent back through the synthesis loop. The unit operates entirely on electricity and includes a high-pressure electrolyzer to obtain gaseous hydrogen and oxygen directly from purified water. Thus, the sole inputs to the trailer are water, carbon dioxide, and electricity, while the sole outputs are methanol, oxygen, and water. A distillation unit separates the methanol and water mixture on site so that the synthesized water can be reused in the electrolyzer. Here, we describe and characterize the operation of the MSU and offer some possible design improvements for future iterations of the device, based on experience.


2011 ◽  
Vol 14 (7-8) ◽  
pp. 780-785 ◽  
Author(s):  
Danielle Ballivet-Tkatchenko ◽  
João H.Z. dos Santos ◽  
Karine Philippot ◽  
Sivakumar Vasireddy

2018 ◽  
Vol 20 (2) ◽  
pp. 131 ◽  
Author(s):  
K. Dossumov ◽  
Y. Yergaziyeva ◽  
L. Myltykbayeva ◽  
M. Telbayeva

The catalytic activity of carriers: θ‒Al2O3, γ‒Al2O3, 5A, 4A, 3A and 13X and the oxides of metals of variable valency ‒ NiO, La2O3, CuO, MoO3, MgO, V2O5, WO3, CoO, Cr2O3, ZnO, ZrO2, CeO2, Fe2O3, supported on the effective carrier γ‒Al2O3 by the method of capillary impregnation of the support with solutions of nitric salts of metals were investigated in the process of carbon dioxide conversion of methane (DRM). The optimal technological regimes for the process were: the reaction temperature -800 °C, the space velocity of the initial reactants ‒ 1500 h-1 with a methane to carbon dioxide ratio equal to 1. It was found that among the studied catalysts the highest activity is shown by the NiO/γ‒Al2O3 catalyst, where the yields of hydrogen and carbon monoxide reaches 45.4 and 42.4% by volume, respectively, when methane conversion is 89%. The XRF method showed that the content of alumina and nickel oxide after the reaction remained unchanged at 96.7 and 3.0%, respectively. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray scattering (XRS) determined that nickel-containing NiO/γ‒Al2O3 catalyst form nickel nanoparticles (6.4‒10 and 50‒150 nm) and a uniform their distribution on the surface of the carrier takes place. These physical chemical characteristics have a positive effect on the activity of NiO/γ‒Al2O3 catalyst in the process of carbon dioxide conversion of methane to synthesis gas.


2020 ◽  
pp. 1-18
Author(s):  
Yu.V. Bilokopytov ◽  
◽  
S.L. Melnykova ◽  
N.Yu. Khimach ◽  
◽  
...  

CO2 is a harmful greenhouse gas, a product of chemical emissions, the combustion of fossil fuels and car exhausts, and it is a widely available source of carbon. The review considers various ways of hydrogenation of carbon dioxide into components of motor fuels - methanol, dimethyl ether, ethanol, hydrocarbons - in the presence of heterogeneous catalysts. At each route of conversion of CO2 (into oxygenates or hydrocarbons) the first stage is the formation of CO by the reverse water gas shift (rWGS) reaction, which must be taken into account when catalysts of process are choosing. The influence of chemical nature, specific surface area, particle size and interaction between catalyst components, as well as the method of its production on the CO2 conversion processes is analyzed. It is noted that the main active components of CO2 conversion into methanol are copper atoms and ions which interact with the oxide components of the catalyst. There is a positive effect of other metals oxides additives with strong basic centers on the surface on the activity of the traditional copper-zinc-aluminum oxide catalyst for the synthesis of methanol from the synthesis gas. The most active catalysts for the synthesis of DME from CO2 and H2 are bifunctional. These catalysts contain both a methanol synthesis catalyst and a dehydrating component, such as mesoporous zeolites with acid centers of weak and medium strength, evenly distributed on the surface. The synthesis of gasoline hydrocarbons (≥ C5) is carried out through the formation of CO or CH3OH and DME as intermediates on multifunctional catalysts, which also contain zeolites. Hydrogenation of CO2 into ethanol can be considered as an alternative to the synthesis of ethanol through the hydration of ethylene. High activation energy of carbon dioxide, harsh synthesis conditions as well as high selectivity for hydrocarbons, in particular methane remains the main problems. Further increase of selectivity and efficiency of carbon dioxide hydrogenation processes involves the use of nanocatalysts taking into account the mechanism of CO2 conversion reactions, development of methods for removing excess water as a by-product from the reaction zone and increasing catalyst stability over time.


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