Study of Standpipe and Loop Seal Behavior in a Circulating Fluidized Bed for Geldart B Particles

The loop seal aeration effect on the supply side has been studied through small scale CFB experimentation. Parameters affected include inventory allocation and entrainment. The gas velocity in the standpipe is influenced by loop seal aeration and riser velocity. Variation in slugging behavior above and below solid downflow velocity of 0.025 m/s is analyzed and discussed here

Progress in Calcium Looping Post Combustion CO2 Capture: Successful Pilot Scale Demonstration

AbstractThe development of Calcium-Looping for CO2 capture has made vast progress in recent time. The technology has become a serious option for CO2 capture from fossile fuel fired power plants. Calcium-Looping is a highly efficient process which uses broadly available natural limestone as a CO2 sorbent. The process uses the reversible reaction (CaCO3↔CaO+CO2) between calcium carbonate and calcium oxide in the temperature range of 650 and 900°C. This publication presents the results of the work done at IFK to demonstrate the Calcium-Looping process in pilot scale at realistic process conditions. The first experimental campaings with the 200 kWth Dual Fluidized Bed (DFB) Facility have shown hydrodynamic stability as well as high flexibility in operation. CO2 capture efficiencies above 90% were achieved consistently over a broad range of process conditions during multiple hours of operation. The presence of water vapor, which is found naturally in flue gas, was found to significantly improve the CO2 capture efficiency. Sorbent attrition measurements fell within a reasonable range, giving confidence that attrition will not be a major restraint for Calcium Looping

Experimental validation of the calcium looping CO2 capture process with two circulating fluidized bed carbonator reactors

[EN] Postcombustion CO2 capture using CaO as a regenerable solid sorbent in a circulating fluidized bed (CFB) carbonator is emerging as a promising CO2 capture technology. Experimental validation of this concept is provided through a comparative analysis of the results obtained in two laboratory-scale dual fluidized bed (DFB) installations located at INCAR-CSIC (Spain) and IFK (Germany). The analysis is focused on the performance of the CFB carbonator reactors operated with continuous solid circulation of CaO. A reasonable closure of the carbon balances (i) between the CO2 that has disappeared from the gas phase, (ii) the CaCO3 circulating between the reactors and (iii) the CaCO3 that is formed within the carbonator bed has been established. A necessary condition for the capture of a given molar flow of CO2 is experimentally demonstrated and requires that a slightly over-stoichiometric molar flow of active CaO is supplied to the carbonator. The deactivation behavior of the sorbents during continuous looping conditions has been measured. The key parameter to interpret the carbonator reactor results has been the active space time, that is indicative of the CaO inventory per molar flow of CO2 participating in the carbonation reaction and of the reaction rate of the solid inventory in the reactor. Two different approaches have been utilized in order to find a suitable expression for this parameter, thus achieving its correlation with the CO2 capture efficiency. A simple model assuming instant mixing of solids and plugflow of the gas has been tested. Based mainly on carbonator active space time variation, the CO2 capture efficiency are shown to lie between 30 % and above 90 %. These results confirm the technical viability of the calcium looping postcombustion CO2 capture process. They have been used for designing the current pilot-plant facilities which are scaled up 20-50 times in regard to the lab-scale units. Moreover, the lab-scale results obtained allow for simulation work to be initiated in regard to the full scale Ca looping application.We thank the European Commision for the financial support under the “CaOling” Project, funded under the 7th Framework ProgrammePeer reviewe

Improvements in Compassion and Fears of Compassion throughout the COVID-19 Pandemic: A Multinational Study

During large-scale disasters, social support, caring behaviours, and compassion are shown to protect against poor mental health outcomes. This multi-national study aimed to assess the fluctuations in compassion over time during the COVID-19 pandemic. Respondents (Time 1 n = 4156, Time 2 n = 980, Time 3 n = 825) from 23 countries completed online self-report questionnaires measuring the flows of compassion (i.e., Compassionate Engagement and Action Scales) and fears of compassion toward self and others and from others (i.e., Fears of Compassion Scales) and mental health at three time-points during a 10-month period. The results for the flows of compassion showed that self-compassion increased at Time 3. Compassion for others increased at Time 2 and 3 for the general population, but in contrast, it decreased in health professionals, possibly linked to burnout. Compassion from others did not change in Time 2, but it did increase significantly in Time 3. For fears of compassion, fears of self-compassion reduced over time, fears of compassion for others showed more variation, reducing for the general public but increasing for health professionals, whilst fears of compassion from others did not change over time. Health professionals, those with compassion training, older adults, and women showed greater flows of compassion and lower fears of compassion compared with the general population, those without compassion training, younger adults, and men. These findings highlight that, in a period of shared suffering, people from multiple countries and nationalities show a cumulative improvement in compassion and reduction in fears of compassion, suggesting that, when there is intense suffering, people become more compassionate to self and others and less afraid of, and resistant to, compassion

Compassion Protects Mental Health and Social Safeness During the COVID-19 Pandemic Across 21 Countries

International audienc