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In the previous work, YBaCo4O7 + δ and Y0.2Ti0.05Dy0.75BaCo4O7 + δ monolithic oxygen carriers worked at low temperature, were reported with good reactivity in oxygen absorption and desorption. Oxygen carriers reacted at low temperature can save amount of energy for the chemical looping air separation process. The objective of this work is to explore the detailed effect of new foreign ion K+ on reaction process of oxygen releasing and the reduction kinetics for YBaCo4O7 + δ and Y0.2Ti0.05Dy0.75BaCo4O7 + δ monolithic oxygen carriers in fixed‐bed reactor. The results showed that introducing K+ can improve the reaction rate of oxygen releasing. The process of oxygen releasing can be described by A model with different model exponentials of 2, 3, and 4. Adding K+ promotes reaction of oxygen releasing. The apparent activation energies and pre‐exponential factor of oxygen releasing process range from 23.11 to 29.72 kJ/mol and 12.46 to 29.73 min−1, respectively. The kinetic model of oxygen releasing process of monolithic oxygen carriers is established based on obtained kinetics parameters. The got kinetics parameters could be used for designing of a chemical looping air separation reactor. [ABSTRACT FROM AUTHOR]

From the thermodynamic analysis of the steam reforming process of raw coke oven gas, the H2 amplification factor after the reforming can reach the highest (over 3.5) in the temperature range between 650 and 800°C, where the bifunctional catalysts to be prepared should have the best CO2 adsorption performances as well as the excellent reforming catalytic performances. In this article, the bifunctional NiO/CaO@C12A7 catalysts were prepared at different preparation parameters, and among them, the catalyst sample prepared at the calcination temperature of 1,000°C and the calcination time of 4 h with co‐precipitation (CP) method showed the best CO2 adsorption capacity as well as the best characterizations. And, in the steam reforming experiments of tar component from RCOG (Raw coke oven gas), under the effect of the bifunctional catalyst, the higher H2 yield was obtained than that over the mixture of the independent reforming catalyst and CO2 sorbent. [ABSTRACT FROM AUTHOR]

In this article, the bifunctional NiO/CaO@C12A7 catalysts having reforming catalytic effect and CO2 adsorption effect were prepared with co‐precipitation method, and were used in the sorption‐enhanced steam reforming process of tar from RCOG for hydrogen production. Among six kinds of samples with different load ratios, the catalyst with the CaO:C12A7:NiO ratio of 70:15:15 showed the best catalytic performance for the steam reforming of tar to produce H2 as well as the excellent characterization. Under the action of this catalyst, the H2 yield obtained from the steam reforming process of 1‐methylnaphthalene (C11H10) as the tar model compound were higher than that from the common steam reforming process, and the best H2 yield was obtained at the reforming temperature of 750°C, the S/C ratio of 12 and the WHSV of 0.055 hr−1, with the value of 83.9%. [ABSTRACT FROM AUTHOR]

Chemical looping air separation, producing oxygen, is a non‐traditional and energy efficient process. Oxygen carrier is core of the process. In the article, practicability of YBaCo4O7+δ and substituted samples reacting at temperature lower than 500°C as oxygen carriers are studied for a chemical looping air separation process. First, the XRD analysis of synthesized samples was performed to discern the formation of 114 phase structure. The TG results obtained by temperature‐programmed thermogravimetry show that YBaCo4O7+δ and substituted samples have high oxygen storage capacity. The DTG results obtained by isothermal and temperature‐programmed thermogravimetry show that YBaCo4O7+δ and substituted samples have a faster oxygen desorption rate and a slower oxygen absorption rate. The isothermal TG results show that the conversion time decreases, and the amount of oxygen absorption/desorption first increases and then decreases, with increasing the operating temperature of oxygen absorption. With increasing the operating temperature of oxygen desorption, the conversion time decreases. The optimal temperature of oxygen absorption and desorption is 330 and 450°C, respectively. Oxygen absorption and desorption processes occur in a highly reversible manner. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 563–569, 2019 [ABSTRACT FROM AUTHOR]

The study on CO2 sorbent to be used in the sorption‐enhanced steam reforming process of raw coke oven gas (RCOG) was performed via thermodynamic and experimental analysis in this article. From the thermodynamic analysis, CaO showed the highest CO2 adsorption capacity in the SR reaction temperature zone of RCOG and the best CO2 desorption efficiency at the higher temperature among eight candidate metal‐oxides, and thus was selected as the active component of CO2 sorbent. Then, the CaO‐based sorbents were prepared with Ca12Al14O33 as carrier and their adsorption performances were tested via thermogravimetric experiment. Under the preparation conditions with the calcined time of 4 h, the calcined temperature of 900°C and the CaO content of 75%, the sorbent sample showed the better CO2 adsorption and cycle stability than the other prepared samples and pure CaO, with its adsorption capacity reaching 47.38%. From the sorption‐enhanced steam reforming experiments, the addition of the selected sorbent can obviously improve the H2 yield, with its concentration approaching 100%, and the optimal reforming temperature was deceased, with the H2 yield obtaining 83.76% at 800°C. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 89–97, 2019 [ABSTRACT FROM AUTHOR]

The combined CLG and CLHG is a novel technology for the co‐generation of syngas and H2‐riched gas. In CLG process, the reduction of oxygen carrier with biomass can produce syngas. In CLHG process, the oxidation of oxygen carrier with steam can produce H2‐riched gas. In this study, the Ce‐based oxygen carrier was selected as the candidate material based on the Gibbs free energy changes (ΔG) of the splitting water reactions. The redox mechanism of the Ce‐based oxygen carrier was discussed and thermodynamic analysis of syngas and hydrogen generation was performed by Gibbs free energy minimization method. The optimal O/C in the GR was determined as 0.6–0.8 and the total dry concentration of CO and H2 was higher than 95.0% under 850–1000°C. The optimal S/C in the SR was determined as 2–3 and the H2 fraction was higher than 70.0% under 850–1000°C. In the AR, all of the Ce oxides can be regenerated to CeO2 in the air flow of 0.5 kmol at 700°C. After one CLG–CLHG cycle, there was no carbon deposition on the surface of oxygen carrier. The redox mechanism of the Ce‐based oxygen carrier was defined as: CeO 2 ↔ CeO 1 . 83 ↔ CeO 1 . 72 ↔ Ce 2 O 3 . © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1132–1139, 2018 [ABSTRACT FROM AUTHOR]

Activated carbons were produced using waste ion‐exchange resin, and the effects of different activation temperatures were researched in this article. The experimental results indicate that the activated carbons are microporous carbons. The BET specific surface area and total volume increase at first and then decrease as the activation temperature increases. The maximum adsorption capacity is 81.24 mg/g at 30°C. A higher adsorption temperature and lower CO2 partial pressure resulted in a lower CO2 adsorption capacity. After 20 adsorption–desorption cycles, the CO2 adsorption capacity decreases slightly, and the regeneration degree is always at a high level, which indicates that the activated carbons can be used for a long time. The results in this work suggest that waste ion‐exchange resin‐based activated carbons show great potential as adsorbents for postcombustion CO2 capture. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 703–711, 2018 [ABSTRACT FROM AUTHOR]

The catalytic activities of the Ni-based catalysts with Ca12Al14O33 as carrier for the steam reforming of tar from coke oven gas were studied. The carriers were prepared with three methods, high temperature roasting (HTR), coprecipitation (CP) and sol−gel (SG), respectively. Compared to the catalyst with CP, the catalyst with HTR showed stronger peaks of NiO as well as Ca12Al14O33, similar to the one with SG, and had obviously higher catalytic activity than those with CP and especially with Al2O3 as carrier, just slightly lower than that with SG. When the calcination temperature was 1350°C (HTR-1350), the prepared catalyst showed the strongest peaks of Ca12Al14O33 and NiO and the highest surface area, resulting in the excellent performance for tar reforming. For Ni/Mg−Ca12Al14O33 catalyst with HTR-1350, the catalytic activity and stability were improved as the reforming temperature and the steam/carbon ratio (S/C) rose, and especially at 850°C and the S/C ratio of 12:1, the hydrogen yield can reach 93.16%, with the carbon conversion reaching 97.14%. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 729-735, 2017 [ABSTRACT FROM AUTHOR]

Chemical looping with oxygen uncoupling and chemical looping air separation technologies all depend on the redox property of oxygen carrier. The present work investigated the redox properties of Cu/Zr oxygen carrier under different oxygen concentrations by TG technique. The durability and stability of oxygen carrier is also investigated under 1065°C reduction and 800°C oxidation temperatures. For reduction, the starting and ending temperatures and the peaks of DTG curves shift to high values with oxygen concentration increasing. The effect of oxygen concentration on oxidation is little and the regeneration of Cu/Zr oxygen carrier can be achieved in thin oxygen environment. For reduction and oxidation, times for complete conversion decrease with heating rates increasing. Kinetic models were proposed based on the nucleation and nuclei growth model. The reduction mechanism function is: [ABSTRACT FROM AUTHOR]

Through thermodynamic analysis, the CO2 sorbent(s) used in the steam reforming process of ethanol as the model compounds of bio-oil was selected from nine common metal oxides. Among them, calcium oxide shows the best CO2 adsorption capacity in the condition of the co-existence of CO2 and H2O in the temperature zone (600-1100 K) where ethanol steam reforming can obtain a higher hydrogen yield, and its carbonate (CaCO3) can easily decompose at slightly higher temperature. Compared to the ethanol steam reforming process with the addition of no any sorbent, the hydrogen yield and purity in the process with CaO as a sorbent were obviously improved, and the temperature range of more than 90% hydrogen yield is widened from 860-1010 K to 705-1085 K. Before the sorbent addition, the maximum hydrogen concentration appear at over 750 K, yet just around 74%, but the hydrogen concentration can overtake 90% in the range of 590-935 K after the addition of CaO. With thermogravimetric analysis, CaO from calcinated calcium acetate shows the highest CO2 adsorption capacity and the best cycle stability, as compared to the other two kinds of CaO, with analytical pure and from calcinated calcium hydroxide. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 1208-1214, 2015 [ABSTRACT FROM AUTHOR]

Dry granulation, as a new process of molten blast furnace slag (BFS) treatment, is an attractive alternative to water quenching. The performance of BFS obtained from dry granulation must be assessed. The glass content, which is a significant factor to evaluate the performance of BFS as a replacement material for Portland cement, was investigated using the X-ray diffraction method. The results indicated that the glass content of BFS decreased as the slag droplet velocity was increased and decreased with an increase in the diameter of the slag particles. For a 2.04 m/s velocity and 0.80 mm diameter of slag particles, the value of the glass content is 94%, which is higher than the 91% content obtained from water quenching. To obtain much higher glass content, it is better to cool the molten BFS from a higher initial temperature. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 485-491, 2015 [ABSTRACT FROM AUTHOR]

With the minimization of the Gibb's free energy, the thermodynamical analysis of the steam reforming processes for the four typical model compounds (ethanol, acetic acid, acetone, and phenol) of bio-oil was systematically performed. In the steam reforming process, the four model compounds can be completely converted. The higher hydrogen yields of the four compounds were obtained via steam reforming than via thermal decomposition. The hydrogen yields first increased and then remained constant and even decreased with temperature, monotonically decreased with the pressure increase, and obviously increased with the steam to carbon ratio. As the steam to carbon ratio rose, the temperatures of the maximum hydrogen yields move afterward to low temperature. When the S/C ratio was 6, the increase rate of hydrogen was decreased. In the co-existence of CaO/CO2/H2O, the reaction between CaO and CO2 was dominant to the reaction between CaO and H2O. By adding CaO, a CO2 sorbent in the steam reforming system, both the yields and the concentration of hydrogen were obviously more pronounced than the processes without CaO. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1008-1016, 2014 [ABSTRACT FROM AUTHOR]