Sorbent Development

As briefly introduced in the previous sections, the sorbent is the most important component in an enhanced reactor since it determines the reactor design and the performance of the process. The sorbent material must have the following characteristics  

Able to adsorb and desorb CO2 over several hundred thousands of cycles from gases with high partial pressures of both steam and CO2  

Show both good mechanical and chemical stability that is a lifetime of at least 5 years  

High cyclic capacity for CO2 and high selectivity over hydrogen and other (trace) components in the gas  

In particular, the high cyclic capacity of the sorbent is one of the key characteristics. The higher the capacity, the more CO2 can be adsorbed per m reactor volume and the less steam for sorbent regeneration is needed reducing the primary energy consumption per ton of CO2 captured. Lifetime and specific sorbent cost are the other two key parameters predominantly affecting the operational cost of the CO2 capture process. 

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AUTO-PUREX G A process for removing carbon dioxide from air by PSA, using alumina as the sorbent. Developed by Marutani Chemical Plant Engineering Company, Japan. 

Applications for adsorption have been limited by the availability of sorbents. The economics of all adsorption processes are also limited by the sorbent improvement in the sorbent will lead to improved economics. Hence, major advances in gas adsorption technology will come from the development of new sorbents. For this reason, special attention will be given to new sorbent development during the last decade. 

Sorbent development. During liquid-phase experiments, 7t-complexation sorbents adsorbed more sulfur (e g. thiophene) at low concentrations than commercial sorbents. Table 1 compares the performance of selected sorbents. 

The second phase of the solid sorbent development was conducted at the Research Triangle Institute (RTI) (3) where many aromatic polyimides were synthesized with the objective of finding a solid sorbent or sorbents that collect VOCs in ambient air. Four polyimides met the study objectives and will be further tested. 

So far many different techniques, such as sol-gel, mechanical mixing, wet-impregnation or co-precipitation have been appUed to develop novel CaO-based CO2 sorbents. However, the new materials were often tested under very different carbonation and calcination conditions than those which would be employed in a practical CO2 capture systan, thus making a proper comparison between the different sorbents developed essentially impossible. Therefore, it is critical that in the future, newly developed CO2 sorbents are tested under identical, standardized conditions, i.e. calcination at 900 C in a pure CO2 atmosphere. 

Eftitz R, Kierzkowska AM, Broda M, MUller CR (2012) Highly efficient CO2 sorbents development of synthetic, calcium-rich dolomites. Environ Sd Technol 46 559-565... 

In this section, the advancement in sorbent development for SERF and SEWGS is presented. 

In theFP7 CAESAR project [9], sorbent development focused on addressing these issues with the hydrotalcite-based sorbent. The objectives here were to increase the cyclic capacity, to reduce the amount of steam needed for regeneration, to increase the mechanical strength of the sorbent pellets and finally to reduce the specific sorbent cost. The key issue was to develop a HTC-based sorbent material that did not form notable amounts of MgC03... 

D., Nickens, and A. (2006) U.S. Navy sorbent development for liquid-phase removal of sulfur from logistics fuels for fuel cell applications. Presented at Fuel Cell Seminar, San Antonio, TX. 

The w-complexation bond is typically a weak bond that can be formed between the sorbent and sorbate. The sorbents that are used for separation and purification based on w-complexation are called w-complexation sorbents. Development of r-complexation sorbents began only recently. A number of such sorbents have already been used commercially, and tremendous potential exists for future applications in separation and purification, both for the chemical/petrochemical industry and environmental applications. For this reason, jr-complexation sorbents are discussed in a separate chapter. 

Sorbent development for methane storage has been an active research area since the 1980 s. The aim of the research is to develop a competitive storage system for natural gas for vehicular use, known as adsorbed natural gas (ANG). 

The large C/Hg ratio could be a result of either mass transfer limitation or a limited mercury capacity of carbon because of the extremely small concentration of mercury in the flue gas, or the limited reactivity of the carbon. To reduce the operating cost of the carbon injection process, either a more efficient sorbent that can operate at a smaller C/Hg ratio, or a lower-cost sorbent, or both is required. An understanding of physical and chemical processes that affects mercury removal from flue gas and a systematic sorbent development study would be required to develop an efficient, cost-effective carbon injection process for removal of mercury from coal-fired utility flue gas. 

Bakker, W.J.W., et al.. Sorbent development for continuous regenerative hydrogen sulphide removal in a rotating monolith reactor. Can. J. Chem. Eng., 74(5). 713-718 (1996). 

Zinc Ferrite and Titanate Sortents Sorbent Development... 

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