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Calcium Looping Process

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Yingjie Li – 1st expert on this subject based on the ideXlab platform

  • Simultaneous NO/CO2 removal by Cu-modified biochar/CaO in carbonation step of Calcium Looping Process
    Chemical Engineering Journal, 2020
    Co-Authors: Wan Zhang, Yingjie Li, Yuqi Qian, Boyu Li, Yuzhuo Wang, Zeyan Wang

    Abstract:

    Abstract A novel method to realize the simultaneous NO/CO2 removal by Cu-modified biochar and CaO in the carbonation stage of Calcium Looping was proposed. Cu-modified biochar was added in the carbonation stage as a NO reductant, meanwhile CaO was added as a CO2 sorbent. The simultaneous NO/CO2 removal performance of Cu-modified coconut shell char/CaO in the carbonation stage of Calcium Looping was investigated in a bubbling fluidized bed reactor. CO is generated by the oxidation of the coconut shell char in the presence of O2 in the carbonation. Cu-modified biochar and the generated CO efficiently reduce NO. Cu in Cu-modified biochar shows a strong catalysis on NO reduction by both char and CO. Besides, Cu enhances the conversion of CO to CO2, which is absorbed by CaO. CaO also catalyzes NO removal by CO, but the catalytic effect gradually becomes weak as the carbonation proceeds. When Cu content in Cu-modified coconut shell char is 0.77%, mass ratio of Cu-modified biochar to CaO is 1:16 and O2 concentration is 3%, NO removal and CO2 capture efficiencies of Cu-modified biochar/CaO in the carbonator are 94% and 80% at 650 °C, respectively. To reach the same NO removal efficiency of 94% in the carbonator, the required addition amount of Cu-modified biochar is only approximately 20% of untreated biochar.

  • simultaneous no co2 removal by cu modified biochar cao in carbonation step of Calcium Looping Process
    Chemical Engineering Journal, 2020
    Co-Authors: Wan Zhang, Yingjie Li, Yuqi Qian, Boyu Li, Yuzhuo Wang, Zeyan Wang

    Abstract:

    Abstract A novel method to realize the simultaneous NO/CO2 removal by Cu-modified biochar and CaO in the carbonation stage of Calcium Looping was proposed. Cu-modified biochar was added in the carbonation stage as a NO reductant, meanwhile CaO was added as a CO2 sorbent. The simultaneous NO/CO2 removal performance of Cu-modified coconut shell char/CaO in the carbonation stage of Calcium Looping was investigated in a bubbling fluidized bed reactor. CO is generated by the oxidation of the coconut shell char in the presence of O2 in the carbonation. Cu-modified biochar and the generated CO efficiently reduce NO. Cu in Cu-modified biochar shows a strong catalysis on NO reduction by both char and CO. Besides, Cu enhances the conversion of CO to CO2, which is absorbed by CaO. CaO also catalyzes NO removal by CO, but the catalytic effect gradually becomes weak as the carbonation proceeds. When Cu content in Cu-modified coconut shell char is 0.77%, mass ratio of Cu-modified biochar to CaO is 1:16 and O2 concentration is 3%, NO removal and CO2 capture efficiencies of Cu-modified biochar/CaO in the carbonator are 94% and 80% at 650 °C, respectively. To reach the same NO removal efficiency of 94% in the carbonator, the required addition amount of Cu-modified biochar is only approximately 20% of untreated biochar.

  • Simultaneous NO/SO 2 removal by coconut shell char/CaO from Calcium Looping in a fluidized bed reactor
    Korean Journal of Chemical Engineering, 2020
    Co-Authors: Boyu Li, Yingjie Li, Wan Zhang, Yuqi Qian, Zeyan Wang

    Abstract:

    A simultaneous NOx/SO2 removal system using bio-char and CaO combined with Calcium Looping Process for CO2 capture was proposed. The simultaneous NO/SO2 removal performance of coconut shell char/CaO experienced CO2 capture cycles was investigated in a fluidized bed reactor. The effects of reaction temperature, mass ratio of CaO to coconut shell coke, CaO particle size and number of CO2 capture cycles from Calcium Looping Process were discussed. The NO removal efficiency of char is improved under the catalysis of CaO. The reaction temperature plays an important role in the simultaneous NO/SO2 removal. Coconut shell char/CaO achieve the highest NO and SO2 removal efficiencies at 825 oC, which are 98% and 100%, respectively. The mass ratio of CaO to coconut shell char of 60: 100 is a good choice for the simultaneous NO/SO2 removal. Smaller CaO particle size contributes to higher NO and SO2 removal efficiencies of coconut shell char/CaO. The NO and SO2 removal efficiencies of coconut shell char and cycled CaO from Calcium Looping declined slightly with the number of CO2 capture cycles. In addition, the Ca-based materials balance in Process of simultaneous NOx/SO2 removal combined with Calcium Looping is given. The novel simultaneous NO/SO2 removal method using bio-char and cycled CaO from Calcium Looping Process appears promising.

Chunmei Lu – 2nd expert on this subject based on the ideXlab platform

  • co2 capture using carbide slag modified by propionic acid in Calcium Looping Process for hydrogen production
    International Journal of Hydrogen Energy, 2013
    Co-Authors: Yingjie Li, Jianli Zhao, Chunmei Lu

    Abstract:

    Abstract Lime enhanced gasification (LEGS) Process based on Calcium Looping in which CaO is employed as CO2 sorbent is an emerging technology for hydrogen production and CO2 capture. In this work, carbide slag which was an industrial solid waste was utilized as CO2 sorbent in hydrogen production Process. Modification of carbide slag by propionic acid was proposed to improve its reactivity. The CO2 capture behavior of raw and modified carbide slags was investigated in a dual fixed-bed reactor (DFR) and a thermo-gravimetric analyzer (TGA). The results show that modification of carbide slag by propionic acid enhances its CO2 capture capacity in the multiple calcination/carbonation cycles. The favorable carbonation temperature and calcination temperature for modified carbide slag are 680–700 °C and 850–950 °C, respectively. Prolonged carbonation treatment is beneficial to CO2 capture of raw and modified carbide slags. The prolonged carbonation for 9 h in the 21st cycle increases the conversions of raw and modified carbide slags in this cycle. And then the carbonation conversions of the two sorbents were also improved in the subsequent cycles. Calcined modified carbide slag shows more porous microstructure compared with calcined raw one for the same number of cycles. Modification of carbide slag by propionic acid increases the surface area, pore volume and pore area. In addition, the volume and area of the pores in 20–100 nm in diameter were improved, which had been proved to be more effective to capture CO2. The microstructure of calcined modified carbide slag favors its higher CO2 capture capacity in the multiple calcination/carbonation cycles.

  • utilization of lime mud from paper mill as co2 sorbent in Calcium Looping Process
    Chemical Engineering Journal, 2013
    Co-Authors: Yingjie Li, Chunmei Lu

    Abstract:

    Abstract Lime mud (LM), a solid waste that results from the causticization reaction in alkali recycling Process of paper manufacture industry, was utilized as CO 2 sorbent in Calcium Looping Process in this study. The carbonation behavior of LM in the calcination/carbonation cycles was investigated in a dual fixed-bed reactor and a thermo-gravimetric analyzer. The results show that the carbonation conversions of LM are lower than those of limestone at the same reaction conditions. It attributes to the high chlorine content in LM which leads to more pronounced sintering and decreases the CO 2 capture performance of LM. A pre-wash Process was employed to decrease the chlorine content in LM. Based on an overall consideration of various factors, the pre-wash Process is effective enough if the Cl/Ca molar ratio in LM is smaller than 1:100. Pre-washed lime mud (PLM) achieves higher carbonation rates and carbonation conversions, compared with LM. When calcined at 850 °C and carbonated at 700 °C, the carbonation conversion of PLM maintains at 36% after 100 cycles, which is 1.8 and 4.8 times as high as LM and limestone after the same number of cycles, respectively. The pore volume and surface area of calcined PLM were greater than those of calcined LM after the same number of cycles, especially the volume of the pores in the range of 10–100 nm in diameter. That is the reason why PLM exhibits higher CO 2 capture capacity than LM in the multiple calcination/carbonation cycles. The carbonation conversions of LM and PLM are further enhanced by hydration of their calcines.

  • CO2 capture using carbide slag modified by propionic acid in Calcium Looping Process for hydrogen production
    International Journal of Hydrogen Energy, 2013
    Co-Authors: Rongyue Sun, Yingjie Li, Jianli Zhao, Changtian Liu, Chunmei Lu

    Abstract:

    Lime enhanced gasification (LEGS) Process based on Calcium Looping in which CaO is employed as CO2 sorbent is an emerging technology for hydrogen production and CO2 capture. In this work, carbide slag which was an industrial solid waste was utilized as CO2 sorbent in hydrogen production Process. Modification of carbide slag by propionic acid was proposed to improve its reactivity. The CO2 capture behavior of raw and modified carbide slags was investigated in a dual fixed-bed reactor (DFR) and a thermo-gravimetric analyzer (TGA). The results show that modification of carbide slag by propionic acid enhances its CO2 capture capacity in the multiple calcination/carbonation cycles. The favorable carbonation temperature and calcination temperature for modified carbide slag are 680-700 C and 850-950 C, respectively. Prolonged carbonation treatment is beneficial to CO2 capture of raw and modified carbide slags. The prolonged carbonation for 9 h in the 21st cycle increases the conversions of raw and modified carbide slags in this cycle. And then the carbonation conversions of the two sorbents were also improved in the subsequent cycles. Calcined modified carbide slag shows more porous microstructure compared with calcined raw one for the same number of cycles. Modification of carbide slag by propionic acid increases the surface area, pore volume and pore area. In addition, the volume and area of the pores in 20-100 nm in diameter were improved, which had been proved to be more effective to capture CO2. The microstructure of calcined modified carbide slag favors its higher CO2 capture capacity in the multiple calcination/carbonation cycles. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Shwetha Ramkumar – 3rd expert on this subject based on the ideXlab platform

  • Process simulation and economic analysis of the Calcium Looping Process clp for hydrogen and electricity production from coal and natural gas
    Fuel, 2013
    Co-Authors: Daniel P. Connell, David A. Lewandowski, Shwetha Ramkumar, Nihar Phalak, Robert M. Statnick

    Abstract:

    Abstract The Calcium Looping Process (CLP) is being developed to facilitate carbon dioxide (CO 2 ) capture during the production of hydrogen (H 2 ) from syngas. The Process integrates CO 2 , sulfur, and halide removal with the water–gas shift (WGS) reaction in a single-stage reactor. In the CLP, a regenerable Calcium oxide (CaO) sorbent is used to chemically react with and remove CO 2 and other acid gases from syngas at high temperature (i.e., 550–700 °C). The removal of CO 2 drives the WGS reaction forward via Le Chatelier’s principle, obviating the need for a WGS catalyst and enabling the production of high-purity H 2 . The spent sorbent is heated in a calciner to regenerate CaO for reuse in the Process and to release a concentrated CO 2 stream, which can be dried and sequestered. The regenerated sorbent is then reactivated in a hydrator, to improve its recyclability, before being reintroduced into the H 2 production reactor. Techno-economic analyses were performed to evaluate the application of the CLP to a coal-to-H 2 plant, a steam methane reforming (SMR) plant, and an integrated gasification-combined cycle (IGCC) plant, all including ⩾90% CO 2 capture. In each case, use of the CLP resulted in a 9–12% reduction in the cost of H 2 or cost of electricity when compared with the use of conventional CO 2 capture and WGS technologies. The economic advantage afforded by the CLP is realized because of the large amount of high-quality heat produced in the Process, which is recovered to raise steam for electricity generation. This heat arises from the combustion of supplemental fuel in the CLP calciner and from the exothermic CO 2 removal, WGS, and hydration reactions, which are carried out at high temperature (i.e., ⩾500 °C) in the CLP. As a result of recovering this heat, the CLP-based coal-to-H 2 and SMR plants, which are designed to produce 26,000 kg/h H 2 , necessarily co-produce 320 MW e and 190 MW e of net electric power, respectively. Although the CLP can reduce the cost of producing H 2 from coal, the resulting cost is still about 26% greater than the cost of H 2 produced from natural gas using conventional WGS and CO 2 capture technologies, assuming coal and natural gas prices of $1.55/GJ and $6.21/GJ, respectively. The lowest cost of H 2 with CO 2 capture for these fuel prices is achieved by applying the CLP to an SMR plant.

  • Process simulation and economic analysis of the Calcium Looping Process (CLP) for hydrogen and electricity production from coal and natural gas
    Fuel, 2013
    Co-Authors: Daniel P. Connell, David A. Lewandowski, Shwetha Ramkumar, Nihar Phalak, Robert M. Statnick, Liang-shih. Fan

    Abstract:

    The Calcium Looping Process (CLP) is being developed to facilitate carbon dioxide (CO2) capture during the production of hydrogen (H 2) from syngas. The Process integrates CO2, sulfur, and halide removal with the water-gas shift (WGS) reaction in a single-stage reactor. In the CLP, a regenerable Calcium oxide (CaO) sorbent is used to chemically react with and remove CO2 and other acid gases from syngas at high temperature (i.e., 550-700 °C). The removal of CO2 drives the WGS reaction forward via Le Chatelier’s principle, obviating the need for a WGS catalyst and enabling the production of high-purity H2. The spent sorbent is heated in a calciner to regenerate CaO for reuse in the Process and to release a concentrated CO2 stream, which can be dried and sequestered. The regenerated sorbent is then reactivated in a hydrator, to improve its recyclability, before being reintroduced into the H2 production reactor. Techno-economic analyses were performed to evaluate the application of the CLP to a coal-to-H2 plant, a steam methane reforming (SMR) plant, and an integrated gasification-combined cycle (IGCC) plant, all including ≥90% CO2 capture. In each case, use of the CLP resulted in a 9-12% reduction in the cost of H2 or cost of electricity when compared with the use of conventional CO2 capture and WGS technologies. The economic advantage afforded by the CLP is realized because of the large amount of high-quality heat produced in the Process, which is recovered to raise steam for electricity generation. This heat arises from the combustion of supplemental fuel in the CLP calciner and from the exothermic CO2 removal, WGS, and hydration reactions, which are carried out at high temperature (i.e., ≥500 °C) in the CLP. As a result of recovering this heat, the CLP-based coal-to-H2 and SMR plants, which are designed to produce 26,000 kg/h H2, necessarily co-produce 320 MWe and 190 MWe of net electric power, respectively. Although the CLP can reduce the cost of producing H2 from coal, the resulting cost is still about 26% greater than the cost of H2 produced from natural gas using conventional WGS and CO2 capture technologies, assuming coal and natural gas prices of $1.55/GJ and $6.21/GJ, respectively. The lowest cost of H2 with CO 2 capture for these fuel prices is achieved by applying the CLP to an SMR plant. © 2012 Elsevier Ltd. All rights reserved.

  • Calcium Looping Process for clean coal conversion design and operation of the subpilot scale carbonator
    Industrial & Engineering Chemistry Research, 2012
    Co-Authors: Nihar Phalak, Shwetha Ramkumar, Niranjani Deshpande, Alan Wang, William S Y Wang, Robert M. Statnick

    Abstract:

    The Calcium Looping Process (CLP), which is being developed at The Ohio State University (OSU), is a clean coal technology for the production of hydrogen (H2) and electricity from coal-derived syng…