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Abstract Carbide slag pellets fabricated by bagasse templating using extrusion-spheronization were proposed to simultaneously remove SO 2 /NO from flue gas. The effects of the reaction temperature, O 2 concentration, mass ratio of bagasse to carbide slag and particle size on the simultaneous SO 2 /NO removal performance of carbide slag pellets were investigated in a bubbling fluidized bed reactor. CaO in the carbide slag pellets has a significant promotion effect on NO reduction by CO. SO 2 and NO are completely removed by the carbide slag pellets at 825–875 °C. The presence of O 2 in the reaction gas results in an adverse effect on NO removal by carbide slag pellets, while it leads to a positive effect on SO 2 removal. With an increase in the mass of bagasse in the pellets, the duration for the complete NO removal becomes longer and the porosity of the pellets appears higher. Carbide slag pellets with a smaller particle size possess a higher NO removal capacity. The higher mass ratio of bagasse to carbide slag leads to a larger surface area and pore volume of the pellets during SO 2 /NO removal process but results in a slight decrease in the attrition resistance. Carbide slag pellets by bagasse templating for simultaneous SO 2 /NO removal seems promising in the industrial application. Highlights • Bagasse templated carbide slag pellets are fabricated by extrusion-spheronization. • Carbide slag provides a significant promotion effect on NO reduction by CO. • Bagasse template improves SO 2 sorption capacity of carbide slag pellets. • Carbide slag pellets achieve efficient simultaneous SO 2 and NO removal. [ABSTRACT FROM AUTHOR]

CaO/CaCO 3 thermochemical energy storage has been considered as a promising technology in the concentrated solar power plants. In this work, the high-alumina granule stabilized soda residue, which contains CaO, MgO, Ca 12 Al 14 O 33 , and Ca 2 SiO 4 , was manufactured by wet-mixing method, and explored for thermochemical energy storage via CaO/CaCO 3 cycles. The effects of the addition amount of high-alumina granule, carbonation pressure, and number of cycles on the energy storage capacity of the stabilized soda residue were investigated. MgO, Ca 12 Al 14 O 33 , and Ca 2 SiO 4 inhibit the growth and agglomeration of CaO grains and enhance the sintering resistance of soda residue; besides, the addition of high-alumina granule increases the basicity of soda residue. Moreover, the increase of carbonation pressure improves the energy storage performance of the stabilized soda residue. Hence, the stabilized soda residue with the mass ratio of high-alumina granule to CaO = 10:100 exhibits the excellent energy storage capacity and cyclic stability in the CaO/CaCO 3 cycles. The energy storage density and effective conversion of the stabilized soda residue are approximately 2394 kJ·kg−1 and 75% after 30 cycles at 1.1 MPa. The stabilized soda residue is an efficient material for CaO/CaCO 3 energy storage system. [Display omitted] • High-alumina granule stabilized soda residue is used for CaO/CaCO 3 energy storage. • The stabilized soda residue contains CaO, MgO, Ca 12 Al 14 O 33 , and Ca 2 SiO 4. • MgO, Ca 12 Al 14 O 33 , and Ca 2 SiO 4 inhibit the growth and sintering of CaO grains. • The stabilized soda residue has high energy storage capacity and cyclic stability. • The stabilized soda residue retains porous and stable structure in CaO/CaCO 3 cycles. [ABSTRACT FROM AUTHOR]

CaO/CaCO 3 thermochemical heat storage has been considered as a competitive technology in concentrated solar power plants. Carbide slag and red mud are solid wastes from the chlor-alkali industry and aluminum industry, respectively. In this work, the red mud/Mn co-doped high alumina cement-stabilized carbide slag was synthesized for CaO/CaCO 3 heat storage. The effects of the addition of high alumina cement and red mud/Mn on the heat storage capacity, cyclic stability, and optical absorption of the modified carbide slag were investigated. The modified carbide slag exhibits excellent heat storage capacity and optical absorption. The Ca 3 Al 2 O 6 and CaMnO 3 inhibit the growth of CaO grains. FeMnO 3 and Ca 2 Fe 2 O 5 possess high optical absorption properties. The additions of Mn and red mud enhance the heat storage rate and basicity of the carbide slag. The effective conversion of the modified carbide slag is 0.62 after 30 cycles, which is 3.1 times as high as that of the untreated carbide slag. The modified carbide slag reaches the optical absorptance of ~58%, which is 6.5 times as high as that of the untreated one. Thus, the red mud/Mn co-doped high alumina cement-stabilized carbide slag is a potential candidate for the CaO/CaCO 3 heat storage system. • A red mud/Mn co-doped high alumina cement-stabilized carbide slag was fabricated. • The composite was proposed to use in CaO/CaCO 3 heat storage cycles. • High alumina cement improves cyclic stability due to formation of Ca 3 Al 2 O 6 in cycles. • The composite shows excellent heat storage capacity and optical absorption in cycles. • Red mud and Mn both enhance optical absorption of the composites in cycles. [ABSTRACT FROM AUTHOR]

A Ca 3 Al 2 O 6 -stabilized carbide slag from calcium looping cycles for CO 2 capture was proposed as a H 2 S sorbent in zero emission carbon process. The H 2 S removal performance of Ca 3 Al 2 O 6 -stabilized carbide slag experienced different calcium looping cycles was investigated in a muti-fixed-bed reactor. The fabricated sorbent containing the mass ratio of CaO to Ca 3 Al 2 O 6 = 73:27 shows higher CO 2 capture capacity. The sulfidation temperature and H 2 S concentration exhibit the important effects on H 2 S removal by the fabricated sorbent from CO 2 capture cycles. The number of CO 2 capture cycles has a little effect on H 2 S removal by the fabricated sorbent. The sulfidation conversions of the fabricated sorbent after 100 CO 2 capture cycles at 60 and 120 min can reach 1.3 and 1.6 times as high as those of carbide slag, respectively. Ca 3 Al 2 O 6 restrains the rapid growth of CaO grains in the fabricated sorbent in CO 2 capture cycles. Compared with carbide slag, the fabricated sorbent possesses larger surface area and more stable structure during CO 2 capture cycles because of the support of Ca 3 Al 2 O 6 , so it exhibits higher sulfidation conversion. H 2 S removal using Ca 3 Al 2 O 6 -stabilized carbide slag from calcium looping cycles seems promising in zero emission carbon process. • C3A-modified carbide slag has high CO 2 uptake and stability in multiple CaL cycles. • The modified carbide slag after CO 2 capture cycles shows excellent H 2 S uptake. • C3A improves CO 2 and H 2 S removal capacities of carbide slag from CaL cycles. • CO 2 capture and H 2 S removal by modified carbide slag can be realized in ZEC process. [ABSTRACT FROM AUTHOR]

A hollow nanostructured CaO-based material fabricated from calcined limestone and glucose by hydrothermal carbonization method was proposed to be used in the process coupled Ca-looping for CO 2 capture and CaO/Ca(OH) 2 heat storage. The effects of hydrothermal temperature and interval in the preparation process on CO 2 capture and heat storage capacities of the hollow CaO were studied. The interaction effect of Ca-looping and heat storage on the performance of the hollow CaO was determined. The hollow nanostructure of CaO decreases the diffusion resistance of CO 2 and steam in its inner. The CO 2 capture capacity of the hollow CaO reaches 0.45 g/g after 20 Ca-looping cycles, which is 1.7 times as high as that of limestone. The hollow CaO (hydrothermal temperature of 170 °C for 6 h) after 10 Ca-looping cycles achieves a heat storage capacity of 0.85 mol/mol during the subsequent heat storage cycles, which is 1.3 times as high as that of limestone. A few heat storage cycles improve pore structure of the sintered hollow CaO after Ca-looping cycles, so its CO 2 capture capacity in the following Ca-looping cycle is enhanced by 94%. Thus, the hollow nanostructured CaO seems promising in the process coupled Ca-looping and CaO/Ca(OH) 2 heat storage. • Hollow nanostructured CaO is prepared from limestone by the carbonaceous templating. • The hollow CaO is used in a process coupled Ca-looping and CaO/Ca(OH) 2 heat storage. • The hollow CaO simultaneously achieves high CO 2 capture and heat storage capacities. • The hollow CaO maintains porous structure during Ca-looping and heat storage cycles. • A few heat storage cycles alleviate the sintering of hollow CaO in Ca-looping cycles. [ABSTRACT FROM AUTHOR]