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Hydrogen-rich syngas was successfully produced from catalytic steam gasification of petroleum coke. This work studied the steam gasification of petroleum coke over KOH, K 2 CO 3 , KNO 3 , CaO, Fe 2 O 3 , K 2 CO 3 –CaO and K 2 CO 3 –Fe 2 O 3 in a pressurized fixed bed. KOH and K 2 CO 3 demonstrated good catalytic activity compared with other catalysts. The carbon conversion efficiency (CCE) increased from 14.7 wt% to 61.4 wt% and 87.9 wt% after adding 10 wt% K 2 CO 3 and 10 wt% KOH, respectively, and H 2 content increased from 60.9 vol% to 66.7 vol% and 64.2 vol%. The increase of gasification temperature and pressure resulted in the increase of CCE. However, raising temperature was beneficial to the increase of H 2 and CO contents, while the elevated pressure was in favor of the formation of CH 4. In addition, the K-catalytic steam gasification of petroleum coke accorded with the oxygen transfer and intermediate hybrid mechanism. Image 1 • Higher gasification temperature helped to increase H 2 and CO contents, while raising pressure favored CH 4 formation. • Using KOH and K 2 CO 3 for steam gasification of petroleum coke could obviously improve CCE and syngas quality. • H 2 contents increased to 66.7 vol% and 64.2 vol% after adding K 2 CO 3 and KOH. • K-promoted catalytic steam gasification accorded with the oxygen transfer and intermediate hybrid mechanism. [ABSTRACT FROM AUTHOR]

Abstract Numerous coal-fired power plants, cement plants and steel mills are concentrated in coastal areas of China, and are three major CO 2 emitters. Seawater may be a potential resource to capture CO 2 in coastal areas. In this study, we used seawater as a CO 2 absorbent to capture CO 2. An online chromatography apparatus was used to determine CO 2 solubility in seawater with different temperatures, pressures and salinities. Then, the thermodynamics and kinetics were studied for the influences of temperature and salinity on CO 2 capture in seawater. The experimental results show that increasing temperature and salinity were adverse to CO 2 capture by seawater because of an increase in Henry's constant from a thermodynamics aspect. The kinetic results show that high temperature and low salinity can increase the CO 2 absorption rate. In order to improve the CO 2 absorption ability of seawater and promote CO 2 fixation in carbonate precipitation, we added CaO as major components of industrial alkaline substances to enhance the seawater absorption of CO 2. CO 2 solubility in seawater with 0.4% CaO increased by 79.25%. It shows that the addition of CaO can enhance greatly seawater capture of CO 2. The seawater and its reinforcement with CaO is a potential method to capture CO 2. Highlights • CO 2 solubility in seawater was measured experimentally at different temperatures and salinities. • A thermodynamic model was built to simulate CO 2 solubility in seawater. • The kinetics of CO 2 absorption in seawater was studied. • Seawater with CaO added can enhance greatly CO 2 capture. [ABSTRACT FROM AUTHOR]

• Mechanism of CO 2 capture in steel-slag-enhanced seawater system was studied. • CO 2 capture ability in seawater with different steel slag components investigated. • Combination of CaO and MgO had strong synergistic effect on CO 2 capture by seawater. • Two-third of CO 2 was captured and stored in calcium carbonate form in the system. • Optimum process for CO 2 absorption capacity and energy consumption was evaluated. Coal-fired power plants, cement plants and steel mills are three major CO 2 emitters in the coastal areas of China. To examine potential CO 2 reduction techniques in coastal areas, we used seawater as a CO 2 absorbent with steel slag added to study the CO 2 absorption capacity. An online chromatography apparatus was used to determine CO 2 solubility in steel-slag-enhanced seawater, and the thermodynamics and kinetics were studied. CO 2 was more soluble in seawater with steel slag than that in seawater alone, and as the concentration of steel slag increased, the CO 2 solubility increased and mass transfer coefficient increased, favoring CO 2 absorption rate by seawater. CO 2 solubility increased on average by 115.56% when the steel slag increased by 1.0%. Among steel slag components, MgO had the strongest ability to enhance CO 2 capture. CO 2 solubility of seawater with 0.4% MgO was 0.0044 at 25 °C and 0.3 MPa. In addition, the combination addition of MgO and CaO had a strong synergistic effect on CO 2 capture by seawater. Fe 2 O 3 had a more remarkable capacity to accelerate CO 2 capture than other steel slag components. The process was simulated by Aspen Plus to study the optimum operating conditions on the CO 2 -seawater-steel slag system. The optimum conditions (a liquid-gas mass ratio of 260, absorber temperature of 30 °C, absorber pressure of 1 atm, and steel slag-gas ratio of 0.10) ensured that CO 2 absorption capacity was above 90% with low energy consumption and cost. Moreover two-thirds of the CO 2 was captured and stored in calcium carbonate form. This process can provide CO 2 capture and storage for coastal areas. [ABSTRACT FROM AUTHOR]

In order to show the structure-activity relationship for CO 2 absorbent, and identify or screen novel and efficient physical solvents of CO 2 , the constant-volume method, the Peng-Robinson equation of state, and a molecular simulation were used to investigate the impacts of type of functional groups, carbon chain length and number of functional groups for nine physical solvents. The three methods produced highly consistent results. Comparison of the CO 2 solubility in solvents with the same carbon numbers but different functional groups suggested that the ester group could promote CO 2 absorption. Investigation of the CO 2 solubility in solvents with one ester group but different carbon chain lengths revealed that longer carbon chains could enhance CO 2 absorption. Analyses of the CO 2 solubility of solvents with one and two ester groups demonstrated that more ester groups could further increase the CO 2 absorption. Therefore, the presence and number of ester groups and increased carbon chain length could promote CO 2 absorption. It provides direction and method for screening of highly efficient CO 2 absorbents and for the design and synthesis of new solvents. • Three methods were used to screen for physical solvents for CO 2 capture. • The ester group could promote CO 2 absorption in physical solvents. • Physical solvents with long carbon chains might facilitate CO 2 absorption. • Physical solvents with more ester groups could enhance CO 2 capture. [ABSTRACT FROM AUTHOR]