Post-combustion CO2 capture from the flue gas is one of the key technology options to reduce greenhouse gases, because this can be potentially retrofitted to the existing fleet of coal-fired power stations. Adsorption processes using solid sorbents capable of capturing CO2 from flue gas streams have shown many potential advantages, compared to other conventional CO2 capture using aqueous amine solvents. In view of this, in the past few years, several research groups have been involved in the development of new solid sorbents for CO2 capture from flue gas with superior performance and desired economics. A variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed. Different methods of impregnating functional groups, including grafting techniques and modifying the support materials, have been discussed to en...

Post-Combustion CO2 Capture Using Solid Sorbents: A Review

In the last few years there has been a rapid growth in governmental funding and research activities worldwide for CO2 capture, storage and utilization (CSU), due to increasing awareness of the link between CO2 accumulation in the atmosphere and global warming. Among the various technologies and processes that have been developed and are emerging for CSU of CO2, solid CO2-adsorbents are widely applied. In this review, these solid CO2-adsorbents are classified into three types according to their sorption/desorption temperatures: low-, intermediate- and high-temperature adsorbents with temperatures ranging from below 200 °C, between 200–400 °C and above 400 °C, respectively. For each type of solid CO2-adsorbent, the synthesis, interaction mechanism with CO2 and sorption performance, potential applications and problems are reviewed. In the last section, several representative CO2-sorption-enhanced catalytic reactions are discussed. It is expected that this review will not only summarize the main research activities in this area, but also find possible links between fundamental studies and industrial applications.

CO2 capture by solid adsorbents and their applications: current status and new trends

Carbon dioxide (CO2) capture using solid sorbents has been recognized as a very promising technology that has attracted intense attention from both academic and industrial fields in the last decade. It is astonishing that around 2000 papers have been published from 2011 to 2014 alone, which is less than three years after our first review paper in this journal on solid CO2 sorbents was published. In this short period, much progress has been made and the major research focus has more or less changed. Therefore, we feel that it is necessary to give a timely update on solid CO2 capture materials, although we still have to keep some important literature results published in the past years so as to keep the good continuity. We believe this work will benefit researchers working in both academic and industrial areas. In this paper, we still organize the CO2 sorbents according to their working temperatures by classifying them as such: (1) low-temperature ( 400 °C). Since the sorption capacity, kinetics, recycling stability and cost are important parameters when evaluating a sorbent, these features will be carefully considered and discussed. In addition, due to the huge amounts of cost-effective CO2 sorbents demanded and the importance of waste resources, solid CO2 sorbents prepared from waste resources and their performance are reviewed. Finally, the techno-economic assessments of various CO2 sorbents and technologies in real applications are briefly discussed.

Recent advances in solid sorbents for CO2 capture and new development trends

Modeling of biomass gasification in fluidized bed

Advances in CO2 capture technology: A patent review

Capturing CO2 in flue gas from fossil fuel-fired power plants using dry regenerable alkali metal-based sorbent

The CO2 capture characteristics of dry potassium-based sorbents were investigated with thermogravimetric analysis (TGA) and a bubbling fluidized-bed reactor. Potassium-based sorbents were prepared by impregnation with potassium carbonate on supports such as coconut activated charcoal (AC1), coal active carbon (AC2), silica gel (SG), and activated alumina (Al2O3). Sorbents such as K2CO3/AC1, K2CO3/AC2, and K2CO3/Al2O3 showed excellent carbonation capacity; The total conversion rates of those sorbents were 97.2, 95.9, and 95.2%, respectively in the TG test, and 89.2, 87.9, and 87.6%, respectively, in the fluidized-bed test. However, K2CO3/SG showed poor carbonation capacity, the total conversion rates were only 34.5 and 18.8%, respectively, in TG and fluidized-bed tests. The differences in carbonation capacity of those sorbents were analyzed by studying the microscopic structure and crystal structure of the supports and the sorbents with X-ray diffraction, scanning electron microscopy, and N2 adsorption tests.

CO2 Absorption Using Dry Potassium-Based Sorbents with Different Supports

Thermogravimetric apparatus (TGA) and X-ray diffraction (XRD) have been used to study the characteristics of potassium-based sorbents for CO2 capture. The carbonation reactivity of K2CO3·1.5H2O and K2CO3 dehydrated from K2CO3·1.5H2O was weak. However, K2CO3 calcined from KHCO3 showed excellent carbonation capacity and no deactivation of sorbents during multiple cycles. The XRD results showed that the sample dehydrated from K2CO3·1.5H2O was K2CO3 with structure of monoclinic crystal (PC#1). The carbonation products of PC#1 included K2CO3·1.5H2O and KHCO3, and K2CO3·1.5H2O was the main product. Correspondingly, K2CO3 with structure of hexagonal crystal (PC#2) was the product calcined from KHCO3, and the main carbonation product of PC#2 was KHCO3. The byproduct of K4H2(CO3)3·1.5H2O for PC#2 would affect the carbonation processes. Hydration tests confirmed the two hypotheses: the hydration reaction will first occur for K2CO3 with structure of monoclinic crystal, and the carbonation reaction will first occur f...

Carbonation and Hydration Characteristics of Dry Potassium-Based Sorbents for CO2 Capture

The sorbent of K2CO3/Al2O3 is a good choice for CO2 capture from flue gas of fossil-fuel-fired power plants. The CO2-capture capacity and regeneration property for K2CO3/Al2O3 were investigated in a bubbling fluidized-bed reactor during multiple cycles. Results show that the carbonation conversion for K2CO3/Al2O3 is greater than 90% during 10 cycles. The microstructure character of K2CO3/Al2O3 is stable. The changes of surface area and pore volume are 8.3 m2/g and 0.036 cm3/g, respectively, after 10 cycles, and there is little change in the pore size distribution. Careful temperature control is important because of the narrow temperature window available for CO2 capture and the highly exothermic nature of the carbonation process. After 10 cycles, the elutriated sorbent is only 2.8 wt % and the reducing rate of average particle size is 0.005 mm/h. The sorbent of K2CO3/Al2O3 shows excellent attrition resistance performance.

Chuanwen Zhao

Papers

Capturing CO2 in flue gas from fossil fuel-fired power plants using dry regenerable alkali metal-based sorbent

CO2 Absorption Using Dry Potassium-Based Sorbents with Different Supports

Carbonation and Hydration Characteristics of Dry Potassium-Based Sorbents for CO2 Capture

Multiple-Cycles Behavior of K2CO3/Al2O3 for CO2 Capture in a Fluidized-Bed Reactor

Two-dimensional computational fluid dynamics simulation of coal combustion in a circulating fluidized bed combustor