Carbon dioxide capture by indirect thermal swing adsorption using 13X zeolite

Insights on Cryogenic Distillation Technology for Simultaneous CO2 and H2S Removal for Sour Gas Fields

Natural gas demand has dramatically increased due to the emerging growth of the world economy and industry. Presently, CO2 and H2S content in gas fields accounts for up to 90% and 15%, respectively. Apart from fulfilling the market demand, CO2 and H2S removal from natural gas is critical due to their corrosive natures, the low heating value of natural gas and the greenhouse gas effect. To date, several gas fields have remained unexplored due to limited technologies to monetize the highly sour natural gas. A variety of conventional technologies have been implemented to purify natural gas such as absorption, adsorption and membrane and cryogenic separation. The application of these technologies in natural gas upgrading are also presented. Among these commercial technologies, cryogenic technology has advanced rapidly in gas separation and proven ideally suitable for bulk CO2 removal due to its independence from absorbents or adsorbents, which require a larger footprint, weight and energy. Present work comprehensively reviews the mechanisms and potential of the advanced nonconventional cryogenic separation technologies for processing of natural gas streams with high CO2 and H2S content. Moreover, the prospects of emerging cryogenic technologies for future commercialization exploitation are highlighted.

Carbon Dioxide Capture from Flue Gas Using Tri-Sodium Phosphate as an Effective Sorbent

Fossil fuels are dominant as an energy source, typically producing carbon dioxide (CO2) and enhancing global climate change. The present work reports the application of low-cost tri-sodium phosphate (TSP) to capture CO2 from model flue gas (CO2 + N2) mixture, in a batch mode and fixed-bed setup. It is observed that TSP has a high CO2 capture capacity as well as high CO2 selectivity. At ambient temperature, TSP shows a maximum CO2 capture capacity of 198 mg CO2/g of TSP. Furthermore, the CO2 capture efficiency of TSP over a flue gas mixture was found to be more than 90%. Fresh and spent materials were characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and Fourier transformed infrared spectroscopy (FTIR). Preliminary experiments were also conducted to evaluate the performance of regenerated TSP. The spent TSP was regenerated using sodium hydroxide (NaOH) and its recyclability was tested for three consecutive cycles. A conceptual prototype for post-combustion CO2 capture based on TSP material has also been discussed.

Molecular Layer Deposition-Modified 5A Zeolite for Highly Efficient CO2 Capture

Effective pore mouth size of 5A zeolite was engineered by depositing an ultrathin layer of microporous TiO₂ on its external surface and appropriate pore misalignment at the interface. As a result, a slightly bigger N₂ molecule (kinetic diameter: 0.364 nm) was effectively excluded, whereas CO₂ (kinetic diameter: 0.33 nm) adsorption was only influenced slightly. The prepared composite zeolite sorbents showed an ideal CO₂/N₂ adsorption selectivity as high as ∼70, a 4-fold increase over uncoated zeolite sorbents, while maintaining a high CO₂ adsorption capacity (1.62 mmol/g at 0.5 bar and 25 °C) and a fast CO₂ adsorption rate.

Rational design of thermo-responsive adsorbents: demand-oriented active sites for the adsorption of dyes

A smart adsorbent is fabricated by incorporating a di-block copolymer through the combination of thermo-responsive groups and demand-oriented active sites into mesoporous silica for temperature swing adsorption of dyes.

Electrical current stimulated desorption of carbon dioxide adsorbed on graphene based structures

The objective of this study was to investigate Joule heating/electric swing adsorption (ESA) as a mode of regeneration and to compare the carbon dioxide (CO₂) adsorption capacity of pristine graphene films and reduced graphene oxide (rGO) aerogels.

Molecular simulation study of the competitive adsorption of H2O and CO2 in zeolite 13X

The presence of H2O in postcombustion gas streams is an important technical issue for deploying CO2-selective adsorbents. Because of its permanent dipole, H2O can interact strongly with materials where the selectivity for CO2 is a consequence of its quadrupole interacting with charges in the material. We performed molecular simulations to model the adsorption of pure H2O and CO2 as well as H2O/CO2 mixtures in 13X, a popular zeolite for CO2 capture processes that is commercially available. The simulations show that H2O reduces the capacity of these materials for adsorbing CO2 by an order of magnitude and that at the partial pressures of H2O relevant for postcombustion capture, 13X will be essentially saturated with H2O .

Challenges of electric swing adsorption for CO(2) capture

This work focuses on the application of electric swing adsorption (ESA) as a selective postcombustion technique to capture and concentrate CO(2) from flue gases of power plants. The initial application should be the capture of CO(2) from flue gases of combined cycle natural gas (NGCC) power plants: the CO(2) content ranges from 3-5 %, with up to 12 % of oxygen. Several challenges to deploy this process for a large-scale application are pointed out. Materials such as amine-modified resins or zeolites should be good candidates for this process (indirect ESA) because they exhibit good loadings at low partial pressures of CO(2). The process design should take into account the temperature increase due to adiabatic operation, pushing the effective loadings to values around 20 % of maximum loading. Several process operations are suggested in order to improve the CO(2) purity and recovery and also to integrate the ESA process with other sources of heat, which may have an important impact in energy consumption.