High Temperature Fluidized Bed Reactor Kinetics With Sintering Inhibitors for Iron Oxidation

2011 ◽  
Author(s):  
F. Al-Raqom ◽  
J. F. Klausner ◽  
D. Hahn ◽  
J. Petrasch ◽  
S. A. Sherif
Keyword(s):  
Particle Size ◽  
Reaction Kinetics ◽  
Fluidized Bed ◽  
Iron Powder ◽  
Experimental Studies ◽  
Fluidized Bed Reactor ◽  
Hydrogen Yield ◽  
Silica Powder ◽  
Powder Bed ◽  
Bed Temperature

High purity hydrogen is produced through a thermochemical water splitting process that utilizes iron reduction-oxidation (redox) reactions. An iron powder bed is fluidized to improve heat and mass transfer thus improving the reaction kinetics. Inert additives which act as sintering inhibitors, such as silica (SiO2) and zirconia (ZrO2), are added to the iron powder, and their effectiveness in inhibiting sintering in the oxidation step is evaluated. The influence of particle size, composition, mass fraction and bed temperature on reaction kinetics is investigated. Incorporation of zirconia in the powder bed is done by mixing it with iron powder or by coating the iron particles with a mixture of 1–3 μm and 44 μm zirconia particles. Two different batches of silica are used for blending with iron powder. The silica powder batches include particle diameters ranging from 0–45 μm and 200–300 μm. The mixing ratios of silica to iron are 0.33, 0.5, 0.67 and 0.75 by apparent volume. Experimental studies are conducted in a bench scale experimental fluidized bed reactor at bed temperatures of 450, 550, 650, 750 and 850 °C. It is verified that increasing the bed temperature and the steam residence time increases the hydrogen yield. Increasing the iron particle size reduces the specific surface area and reduces the hydrogen yield. It has been found that sintering can be completely inhibited by mixing iron with 0–45 μm silica powder and maintaining the reaction temperature below 650 °C.

scholarly journals Hydrogen Gas Production from Gasification of Oil Palm Empty Fruit Bunch (EFB) in a Fluidized Bed Reactor

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Siti Suhaili Shahlan ◽  
Kamarizan Kidam ◽  
Tuan Amran Tuan Abdullah ◽  
Mohamad Wijayanuddin Ali ◽  
Ljiljana Medic Pejic ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Oil Palm ◽  
Experimental Studies ◽  
Fluidized Bed Reactor ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Hydrogen Yield ◽  
Production Of Hydrogen ◽  
Palm Waste ◽  
Oil Palm Waste

Malaysia is one of the largest producers of palm oil and this industry plays an important role in Malaysia economic growth. As this industry grows larger, a significant amount of oil palm waste is generated, creating the problem of overloading biomass waste. Since the oil palm waste has many significant uses such as empty fruit bunches (EFB), the interest in production of hydrogen gas as the renewable energy from EFB also increases. The most common and favorable thermochemical processes to produce the hydrogen gas is gasification process in fluidized bed reactor. Regardless of tremendous experimental studies done on effectiveness of using EFB for production of hydrogen, the process implementation in industry is still discouraging. This is due to lack of proven technology and high capital cost of investment.  In this study, a computational modeling was developed for EFB gasification in fluidized bed gasifier using the ASPEN PLUS simulator (v. 8.8) to optimize the gasification temperature, pressure and to study the different of chemical behavior. The results indicated that increase in temperature will increases the production of hydrogen and enhances carbon conversion efficiency. The optimum temperature and pressure was 850 °C and 1.035 bar respectively. The result shows that the char was removed significantly after several gas cleaning process. The final product for purified hydrogen gas is 14.5 kg/hr which is around 21% of hydrogen yield. Based on the result, it indicates that EFB has a potential to be used as a source of energy in a future.

Cold-Model Study on Fluidized-Bed Photo-Oxidation Reactor for Shenfu Coal

2011 ◽  
Vol 201-203 ◽  
pp. 2741-2744
Author(s):  
Ya Ting Zhang ◽  
Guang Heng Wang ◽  
Wei Zhao ◽  
An Ning Zhou
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Pipe Diameter ◽  
Flow State ◽  
Cold Model ◽  
Photo Oxidation ◽  
Model Study ◽  
Oxidation Reactor

The flow state of both the solid and gas phase in the fluidized-bed photo-oxidation reactor for Shenfu coal was studied by cold-model tests. The results showed that the appropriate pipe diameter, particle size of coal, and the coal addition for the gas-solid fluidized-bed reactor were 22 mm, 60-80 mesh, and 10g, respectively.

Internally Circulating Fluidized Bed Reactor Using m-ZrO2 Supported NiFe2O4 Particles for Thermochemical Two-Step Water Splitting

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Nobuyuki Gokon ◽  
Hiroki Yamamoto ◽  
Nobuyuki Kondo ◽  
Tatsuya Kodama
Keyword(s):  
Fluidized Bed ◽  
Water Splitting ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Thermal Reduction ◽  
Input Power ◽  
Light Irradiation ◽  
Bed Temperature ◽  
N2 Flow Rate

A windowed internally circulating fluidized bed reactor was tested using m-ZrO2-supported NiFe2O4(NiFe2O4/m-ZrO2) particles as redox material for thermochemical two-step water splitting to produce hydrogen from water. The internally circulating fluidized bed of NiFe2O4/m-ZrO2 particles is directly heated by solar-simulated Xe light irradiation through a transparent quartz window mounted on top of the reactor. A sun simulator with three Xe lamps at laboratory scale has been newly installed in our laboratory for testing the fluidized bed reactor. The input power of incident Xe light can be scaled up to 2.6 kWth. Temperature distributions within the fluidized bed are measured under concentrated Xe light irradiation with an input power of 2.6 kWth. Hydrogen productivity and reactivity for the fluidized bed of NiFe2O4/m-ZrO2 particles are examined using two different reactors under the N2 flow rate and flow ratio, which yield a higher bed temperature. The feasibility of successive two-step water splitting using the fluidized bed reactor is examined by switching from N2 gas flow in the thermal reduction step to a steam/N2 gas mixture in the water decomposition step. It is confirmed that hydrogen production takes place in the single fluidized bed reactor by successive two-step water splitting.

Experimental Studies on H2-Rich Gas Production by Co-Gasification of Coal and Biomass in an Intermittent Fluidized Bed Reactor

2013 ◽  
Vol 724-725 ◽  
pp. 1127-1131 ◽  
Author(s):  
Li Qun Wang ◽  
Zhao Sheng Chen
Keyword(s):  
Fluidized Bed ◽  
Experimental Studies ◽  
Fluidized Bed Reactor ◽  
Gas Production ◽  
Molar Ratio ◽  
Carbon Conversion ◽  
Mass Ratio ◽  
Heating Value ◽  
Product Gas ◽  
Gasification Temperature

This paper illustrates the experimental results of co-gasification of biomass and coal in an intermittent fluidized bed reactor, aiming to investigate the effects of gasification temperature (T) and steam to biomass mass ratio (SBMR) on the composition, yield, low heating value (LHV) and carbon conversion efficiency of the product gas. The results show that H2-rich gas with a high LHV is generated, in the range of 12.22-18.67 MJ/Nm3, and the H2 content in the product gas is in the range of 28.7-51.4%. Increases in temperature lead to an increase in CO and H2 content. The H2/CO molar ratio in the product gas is close to 1 at temperature above 925 °C. With steam addition, the H2 content increases gradually, while the content of CO increases first and then decrease correspondingly. The molar ratio of H2/CO is close to 1 with the smallest supplied amount of steam addition (SBMR =0.4).

scholarly journals COMPUTATIONAL AND EXPERIMENTAL STUDY OF GRANULATION IN FLUIDIZED BED REACTOR

2019 ◽  
Vol 62 (5) ◽  
pp. 97-103
Author(s):  
Vadim E. Mizonov ◽  
Andrey V. Mitrofanov ◽  
Katia Tannous ◽  
Lev N. Ovchinnikov
Keyword(s):  
Experimental Study ◽  
Particle Size ◽  
Fluidized Bed ◽  
Transition Probabilities ◽  
Cell Model ◽  
Size Fraction ◽  
Fluidized Bed Reactor ◽  
The State ◽  
Time Step ◽  
A Cell

The objective of the study is to build a simple but informative model to describe the kinetics of layering granulation in a batch fluidized bed reactor. A cell model based on the theory of Markov chains to describe this kinetics is proposed. Several parallel chains of perfectly mixed cell according to the number of size fractions, which are under observation, were introduced. The vectors of particles volume content in the cells describe the state of the process. Evolution of the state is conditioned by particles transition from the cells of one chain to another due to their size enlargement during granulation and by particles migration along the chains due to their interaction with fluidizing gas upstream flow. The process is observed in a discrete moments of time. It is supposed that the volume of binding solution coming into a cell of a chain during one time step interacts only with the particles that can enlarge their size to transit to the cell of the next larger size fraction. The migration of the particles of a size fraction along its chain is controlled by the matrix of transition probabilities, which is different for each size fraction and depends on the total particles concentration. The model allows qualitative estimating of influence of the process parameters on the granulation kinetics. In order to validate the model, the experimental study of ammonium sulphate granulation in the lab scale fluidized bed reactor was carried out. The comparison of theoretical and experimental results was done for the example of particle size enlargement at different flow rate of the binding solution feed. A good correlation between theoretical and experimental data was found for both the mean particle size growth and the fraction size distribution at different moments of time.

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