Zongliang Zuo

Hydrogen production via steam reforming of bio-oil model compounds over supported nickel catalysts

Abstract The steam reforming of four bio-oil model compounds (acetic acid, ethanol, acetone and phenol) was investigated over Ni-based catalysts supported on Al 2 O 3 modified by Mg, Ce or Co in this paper. The activation process can improve the catalytic activity with the change of high-valence Ni (Ni 2 O 3 , NiO) to low-valence Ni (Ni, NiO). Among these catalysts after activation, the Ce-Ni/Co catalyst showed the best catalytic activity for the steam reforming of all the four model compounds. After long-term experiment at 700 °C and the S/C ratio of 9, the Ce-Ni/Co catalyst still maintained excellent stability for the steam reforming of the simulated bio-oil (mixed by the four compounds with the equal masses). With CaO calcinated from calcium acetate as CO 2 sorbent, the catalytic steam reforming experiment combined with continuous in situ CO 2 adsorption was performed. With the comparison of the case without the adding of CO 2 sorbent, the hydrogen concentration was dramatically improved from 74.8% to 92.3%, with the CO 2 concentration obviously decreased from 19.90% to 1.88%.

Analysis of oxygen releasing rate of Cu-based oxygen carrier in N2–O2 atmosphere

Technologies of chemical looping with oxygen uncoupling (CLOU) and chemical looping air separation (CLAS) all depend on oxygen releasing property of oxygen carriers used. The oxygen releasing rate of oxygen carrier is controlled by heat and mass transfers as well as chemical reaction rate. In this work, Cu/Zr oxygen carrier was prepared. X-ray diffraction, scanning electron microscopy, and surface area analyzer (BET) were used to characterize the oxygen carrier before and after cyclic experiment. The effects of particle size, gas flow, reaction temperature, oxygen concentration, and cyclic number on oxygen releasing rate were investigated on the thermogravimetric analyzer. The results show that the oxygen releasing rate increases significantly with increasing of temperature. The starting temperatures of reduction reactions shift to high level as oxygen concentrations increase. The effects of particle size and gas flow are little. The oxygen releasing rates during cyclic experiment are almost the same. The main phases in fresh and reoxidized particles are CuO and ZrO2, and in reduced particles are Cu2O and ZrO2. The surfaces of reacted particles have no obvious agglomeration. The oxygen releasing rate is controlled by chemical reaction of the particle. The results obtained are essential to the design of CLOU and CLAS systems.

Thermogravimetric analysis of the biomass pyrolysis with copper slag as heat carrier

Thermo gravimetric analysis experiments were carried out on pyrolysis of three kinds of biomasses by temperature programming method. Employed by thermogravimetric analyzer, the effects of the type of biomass and the ratio of copper slag addition on pyrolysis were studied. Biomass pyrolysis process can be divided into four stages, dehydration, pre-pyrolysis, pyrolysis and carbonization. The experimental yields in this paper were modeled by CH4, C2H6, C3H8, C2H4 and C3H6, considering first-order primary reaction and reactions of alkanes and alkenes. Copper slag is beneficial for biomass pyrolysis. With Coats–Redfern method, nonlinear regression of biomass catalytic pyrolysis showed that reaction mechanism of pyrolysis process confirms well with shrinking core model (A3). The kinetic parameters and equations were also calculated. Copper slag promotes both the primary reactions of biomass pyrolysis and the Cracking reactions of alkanes and alkenes, but it cannot decrease the activation energy effectively.

Particles Flow Behavior Around Tubes in Moving Bed

Moving bed has been widely used in the field of heat and mass transfer and reaction between solid particles and gas. In order to enhance the heat exchange coefficient, there will be tube banks inserted in the moving bed. In the process of drying ammoniates particles or heat recovery from high-temperature particles with moving bed, the particles flow behavior around the tube banks is significant. In this paper, the particles flow behavior around the tube banks is investigated, and all the results can provide guidance for the design and operation of a moving bed.

Direct Reduction of Copper Slag Composite Pellets Within Lignite Using Biomass as Binder

The resource utilization of copper slag is an attractive option of iron resource. Thermal energy recovery and direct reduction (TER-DR) system was proposed in this study. By theoretical analysis, the exergy efficiency of this system can reach to 57.3%. To investigate the feasibility of TER-DR system, copper slag composite pellets within lignite were prepared. As a new binder, pine sawdust was added into the pellets. The diameter of pellets was 20 mm in experiments and the compressive strength of them was up to 831 N when the addition ratio of biomass was 29%. The results showed that the overall iron recovery reached to 90% and the separated iron concentrate was up to 93.5% when the temperature is at 1423 K for 90 min with CaO addition ratio of 0.3. The process reduces the secondary environmental pollution of copper slag and will be applied well in the future.

Preparation and Characterization of Activated Carbon from Waste Ion-Exchange Resin for CO 2 Adsorption

Activated carbons, derived from waste ion-exchange resin by CO2 physical activation, were applied to separate CO2 from flue gas against global warming. The BET specific surface areas of activated carbons at different activation temperatures and times were investigated. The CO2 adsorption capacity was tested under non-isothermal and isothermal conditions. The experimental results show that when keeping the activation temperature constant, the specific surface area increases firstly and then decreases with increasing activation time. For the given activation time, the specific surface area rises firstly and then declines with increasing activation temperature. The adsorption capacity decreases with increasing temperature. The maximum adsorption capacity is 51.46 mg/g under the condition of 298 K and pure CO2. Fractional order kinetic model is the best one to describe the kinetics of CO2 adsorption. The activated carbons show the potential to be an effective adsorbent for the removal of CO2 from flue gas.

Comparative kinetic study of coal gasification with steam and CO2 in molten blast furnace slags

To make a comparison between coal gasification in molten blast furnace slag (MBFS) in different ambience and choose an appropriate agent to recover BF slag’s waste heat entirely, coal gasification with steam and CO2 in molten blast furnace slags was studied by isothermal thermo-gravimetric analysis. The effects of temperature and addition of MBFS were studied. Carbon conversion and reaction rate increased with increasing temperature and MBFS. Volumetric model (VM), shrinking core model (SCM), and diffusion model (DM) were applied to describe the coal gasification behavior of FX coal. The most appropriate model describing the coal gasification was SCM in steam ambience and VM in CO2 ambience, respectively. The reaction rate constant k(T) in CO2 ambience is greater than that in steam ambience, which means the gasification reactivity of coal in CO2 ambience is better than that in steam ambience. BF slag can effectively reduce the activation energy EA of coal gasification reaction in different ambiences. But, the difference of activation energies is not large in different ambiences. Based on the results of kinetic analysis including k(T) and EA calculated by the established model, CO2 was chosen to be the most appropriate agent.