Coal Coke Gasification in a Windowed Solar Chemical Reactor for Beam-Down Optics

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Tatsuya Kodama ◽  
Nobuyuki Gokon ◽  
Shu-ich Enomoto ◽  
Shouta Itoh ◽  
Tsuyoshi Hatamachi
Keyword(s):  
Size Fraction ◽  
Chemical Reactor ◽  
Power Input ◽  
Reaction Site ◽  
Coal Particles ◽  
Energy Peak ◽  
Thermochemical Processes ◽  
Efficient Heat Transfer ◽  
Co2 Flow ◽  
Reactor Operating

Solar thermochemical processes, such as solar gasification of coal, require the development of a high temperature solar reactor operating at temperatures above 1000°C. Direct solar energy absorption by reacting coal particles provides efficient heat transfer directly to the reaction site. In this work, a windowed reactor prototype designed for the beam-down optics was constructed at a laboratory scale and demonstrated for CO2 gasification of coal coke using concentrated visible light from a sun-simulator as the source of energy. Peak conversion of light energy to chemical fuel (CO) of 14% was obtained by irradiating a fluidized bed of 500–710 μm coal coke size fraction with a power input of about 1 kW and a CO2 flow-rate of 6.5 dm3 min−1 at normal conditions.

Application of an Internally Circulating Fluidized Bed for Windowed Solar Chemical Reactor with Direct Irradiation of Reacting Particles

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Tatsuya Kodama ◽  
Syu-ichi Enomoto ◽  
Tsuyoshi Hatamachi ◽  
Nobuyuki Gokon
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Chemical Reactor ◽  
Thermal Reduction ◽  
Storage Efficiency ◽  
Solar Reactor ◽  
Direct Irradiation ◽  
Thermochemical Processes ◽  
Reactor Operating ◽  
Reduction Of Metal Oxides

Solar thermochemical processes require the development of a high-temperature solar reactor operating at 1000–1500°C, such as solar gasification of coal and the thermal reduction of metal oxides as part of a two-step water splitting cycle. Here, we propose to apply “an internally circulating fluidized bed” for a windowed solar chemical reactor in which reacting particles are directly illuminated. The prototype reactor was constructed in a laboratory scale and demonstrated on CO2 gasification of coal coke using solar-simulated, concentrated visible light from a sun simulator as the energy source. About 12% of the maximum chemical storage efficiency was obtained by the solar-simulated gasification of the coke.

Using the Kalman Filtering for the Fault Detection and Isolation (FDI) in the Nonlinear Dynamic Processes

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Yahya Chetouani
Keyword(s):  
Fault Detection ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic System ◽  
Chemical Reactor ◽  
Fault Detection And Isolation ◽  
Decision Threshold ◽  
Normal Behaviour ◽  
Batch Mode ◽  
The Moment ◽  
Reactor Operating

This paper presents a Fault Detection and Isolation (FDI) method for stochastic nonlinear dynamic systems. First, the developed fault detection method is based on statistical information generated by the extended Kalman filter (EKF) and is intended to reveal any drift from the normal behaviour of the process. A fault of a chemical origin in a perfectly stirred batch chemical reactor, occurring at an unknown instant, is simulated. The purpose is to detect the presence of this abrupt change, and pinpoint the moment it occurred. It is also shown that the convergence of the EKF is accomplished more or less rapidly according to the nature of the noise generated by the measurement sensors. The state estimate is observed and discussed, as well as the time delay in detection according to the decision threshold. Then, this study shows another method of tackling the problem of the physical origin diagnosis of faults by combining the technique based on the standardized innovations and the technique using the multiple extended Kalman filters for a strongly non-stationary nonlinear dynamic system. The usefulness of this combination is the implementation of all the fault dynamics models if the decision threshold on the standardized innovation exceeds a determined threshold. In the other case, one EKF is enough to estimate all the process state. An algorithm is described and applied to a perfectly stirred chemical reactor operating in a semi-batch mode. The chemical reaction used is an exothermic second order one.

Development of a High Pressure Dry Coal Feed System for a 100 kWt Oxy-Coal Reactor

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Taylor Schroedter ◽  
Bradley R. Adams ◽  
Jacob Tuia ◽  
Andrew Fry
Keyword(s):  
Particle Diameter ◽  
Flow Ratio ◽  
Feed System ◽  
Horizontal Pipe ◽  
Bench Scale ◽  
Coal Particles ◽  
Simplifying Assumptions ◽  
Coal Flow ◽  
Co2 Flow ◽  
Burner Operation

Abstract A design concept to feed dry coal from a hopper to a 100 kWt pressurized oxy-coal (POC) reactor using CO2 at 2 MPa was developed using transient computational fluid dynamics (CFD) simulations and bench-scale measurements. The feed system was required to maintain a steady flow of gas and solids at a coal flowrate of approximately 3.8 g/s and a CO2-to-coal mass ratio in the range 1–2. A 5.08-cm diameter vertical coal hopper feeding into a 0.635-cm diameter horizontal pipe was used to represent key elements of the feed system. A fluidized bed concept was found capable of providing the desired coal flowrate and CO2-to-coal flow ratio. Use of separate fluidization and dilution flows allowed the coal flowrate and CO2-to-coal flow ratio to be controlled independently. The amount of coal transported from the hopper was dependent on the net CO2 flow in the hopper but independent of the CO2 dilution flow. Pipe exit coal flowrates were found to fluctuate at levels acceptable for steady burner operation. Tests from a bench-scale apparatus using Pittsburgh 8 coal with a median particle diameter of 50 µm and moisture content of 6% confirmed the feasibility of the fluidization design. However, for a given CO2 fluidization flowrate, experimental coal flowrates were lower than predicted coal flow, in part due to simplifying assumptions of dry, spherical coal particles and smooth piping in the simulations.

scholarly journals Poisoning-induced exchange of steady states in a catalytic chemical reactor

1980 ◽  
Vol 22 (2) ◽  
pp. 237-253 ◽  
Author(s):  
D. D. Do ◽  
R. H. Weiland
Keyword(s):  
Steady State ◽  
Asymptotic Expansions ◽  
Phase Plane ◽  
Exchange Process ◽  
Chemical Reactor ◽  
Matched Asymptotic Expansions ◽  
Catalyst Poisoning ◽  
Independent Variables ◽  
Sudden Failure ◽  
Reactor Operating

AbstractSlow catalyst poisoning can result in the sudden failure of a chemical reactor operating isothermally with substrate-inhibited kinetics. At failure, a satisfactory steady state is exchanged for one of low conversion. The method of matched asymptotic expansions is used to give a detailed description of the exchange process in the phase plane. The structure of the jump is ascertained by separate asymptotic expansions across two adjoining transition regions in which the independent variables contain unknown shifts.

scholarly journals Increase of Productivity and Neutralization of Pathological Processes in Plants of Grain and Fruit Crops with the Help of Aqueous Solutions Activated by Plasma of High-Frequency Glow Discharge

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2161
Author(s):  
Yuri K. Danilejko ◽  
Sergey V. Belov ◽  
Alexey B. Egorov ◽  
Vladimir I. Lukanin ◽  
Vladimir A. Sidorov ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Aqueous Solutions ◽  
Chemical Reactor ◽  
Fruit Crops ◽  
Plasma Chemical Reactor ◽  
Set Up ◽  
Reactor Operating ◽  
Short Time ◽  
First Time ◽  
Positive Effect

In this work, we, for the first time, manufactured a plasma-chemical reactor operating at a frequency of 0.11 MHz. The reactor allows for the activation of large volumes of liquids in a short time. The physicochemical properties of activated liquids (concentration of hydrogen peroxide, nitrate anions, redox potential, electrical conductivity, pH, concentration of dissolved gases) are characterized in detail. Antifungal activity of aqueous solutions activated by a glow discharge has been investigated. It was shown that aqueous solutions activated by a glow discharge significantly reduce the degree of presence of phytopathogens and their effect on the germination of such seeds. Seeds of cereals (sorghum and barley) and fruit (strawberries) crops were studied. The greatest positive effect was found in the treatment of sorghum seeds. Moreover, laboratory tests have shown a significant increase in sorghum drought tolerance. The effectiveness of the use of glow-discharge-activated aqueous solutions was shown during a field experiment, which was set up in the saline semi-desert of the Northern Caspian region. Thus, the technology developed by us makes it possible to carry out the activation of aqueous solutions on an industrial scale. Water activated by a glow discharge exhibits antifungicidal activity and significantly accelerates the development of the grain and fruit crops we studied. In the case of sorghum culture, glow-discharge-activated water significantly increases drought resistance.

A 300 kW Solar Chemical Pilot Plant for the Carbothermic Production of Zinc

Solar Energy ◽  
2006 ◽  
Author(s):  
C. Wieckert ◽  
E. Guillot ◽  
M. Epstein ◽  
G. Olalde ◽  
S. Sante´n ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Chemical Reactor ◽  
Packed Bed ◽  
Power Input ◽  
Energy Conversion Efficiency ◽  
Reaction Chamber ◽  
Solar Absorber ◽  
Optical Configuration ◽  
Reduction Of Zno ◽  
Eu Project

In the framework of the EU-project SOLZINC, a 300 kW solar chemical pilot plant for the production of zinc by carbothermic reduction of ZnO was experimentally demonstrated in a beam-down solar tower concentrating facility of Cassegrain optical configuration. The solar chemical reactor, featuring two cavities, of which the upper one is functioning as the solar absorber and the lower one as the reaction chamber containing a ZnO/C packed bed, was batch-operated in the 1300–1500 K range and yielded 50 kg/h of 95%-purity Zn. The measured energy conversion efficiency — ratio of the reaction enthalpy change to the solar power input — was 30%. Zinc finds application as a fuel for Zn-air batteries and fuel cells, and can also react with water to form high-purity hydrogen. In either case, the chemical product is ZnO, which in turn is solar-recycled to Zn. The SOLZINC process provides an efficient thermochemical route for the storage and transportation of solar energy in the form of solar fuels.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Isothermal Continuous Flow Chemical Reactor

1994 ◽  
Vol 59 (8) ◽  
pp. 1772-1787
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Continuous Flow ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Chemical Reactor ◽  
Point Of View ◽  
General Point ◽  
Stochastic Description ◽  
One Dimensional ◽  
Reactor Operating ◽  
Parameter Values

A model of an isothermal one-dimensional continuous flow chemical reactor operating at the steady state was derived using a stochastic description of motion of the reacting molecules. The model enables evaluation of the conversion of the reacting components. At the limiting parameter values the model yields results identical to those of the simplified models conventionally used in chemical reactor engineering. The model also enables the applicability of Danckwerts' boundary conditions to be assessed from a more general point of view.

New Solar Water-Splitting Reactor With Ferrite Particles in an Internally Circulating Fluidized Bed

2007 ◽  
Author(s):  
Nobuyuki Gokon ◽  
Shingo Takahashi ◽  
Hiroki Yamamoto ◽  
Tatsuya Kodama
Keyword(s):  
Metal Oxide ◽  
Fluidized Bed ◽  
Water Splitting ◽  
Circulating Fluidized Bed ◽  
Thermal Reduction ◽  
Solar Irradiation ◽  
Solar Water Splitting ◽  
Oxide Particles ◽  
Efficient Heat Transfer ◽  
Reactor Operating

The thermal reduction of metal oxides as part of a thermochemical two-step water splitting cycle requires the development of a high temperature solar reactor operating at 1000–1500°C. Direct solar energy absorption by metal-oxide particles provides efficient heat transfer directly to the reaction site. This paper describes experimental results of a windowed thermochemical water-splitting reactor using an internally circulating fluidized bed of the reacting metal-oxide particles under direct solar irradiation. The reactor has a transparent quartz window on the top as aperture. The concentrated solar radiation passes downward through the window and directly heats the internally circulating fluidized bed of metal-oxide particles. Therefore, this reactor needs to be combined with a solar tower or beam down optics. NiFe2O4/m-ZrO2 (Ni-ferrite supported on zirconia) particles is loaded as the working redox material in the laboratory scale reactors, and thermally reduced by concentrated Xe-beam irradiation. In a separate step, the thermally-reduced sample is oxidized back to Ni-ferrite with steam at 1000°C. As the results, the conversion of ferrite reached about 44% of maximum value in the reactor by 1kW of incident solar power. The effects of preheating temperature and particle size of NiFe2O4/m-ZrO2 were tested for thermal reduction of internally circulating fluidized bed in this paper.

A 300kW Solar Chemical Pilot Plant for the Carbothermic Production of Zinc

2006 ◽  
Vol 129 (2) ◽  
pp. 190-196 ◽  
Author(s):  
C. Wieckert ◽  
U. Frommherz ◽  
S. Kräupl ◽  
E. Guillot ◽  
G. Olalde ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Chemical Reactor ◽  
Packed Bed ◽  
Power Input ◽  
Energy Conversion Efficiency ◽  
Reaction Chamber ◽  
Solar Absorber ◽  
Optical Configuration ◽  
Reduction Of Zno ◽  
Eu Project

In the framework of the EU-project SOLZINC, a 300-kW solar chemical pilot plant for the production of zinc by carbothermic reduction of ZnO was experimentally demonstrated in a beam-down solar tower concentrating facility of Cassegrain optical configuration. The solar chemical reactor, featuring two cavities, of which the upper one is functioning as the solar absorber and the lower one as the reaction chamber containing a ZnO/C packed bed, was batch-operated in the 1300–1500 K range and yielded 50 kg/h of 95%-purity Zn. The measured energy conversion efficiency, i.e., the ratio of the reaction enthalpy change to the solar power input, was 30%. Zinc finds application as a fuel for Zn/air batteries and fuel cells, and can also react with water to form high-purity hydrogen. In either case, the chemical product is ZnO, which in turn is solar-recycled to Zn. The SOLZINC process provides an efficient thermochemical route for the storage and transportation of solar energy in the form of solar fuels.

New Solar Water-Splitting Reactor With Ferrite Particles in an Internally Circulating Fluidized Bed

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
Nobuyuki Gokon ◽  
Shingo Takahashi ◽  
Hiroki Yamamoto ◽  
Tatsuya Kodama
Keyword(s):  
Metal Oxide ◽  
Fluidized Bed ◽  
Water Splitting ◽  
Circulating Fluidized Bed ◽  
Thermal Reduction ◽  
Beam Irradiation ◽  
Solar Water Splitting ◽  
Oxide Particles ◽  
Efficient Heat Transfer ◽  
Reactor Operating

The thermal reduction of metal oxides as part of a thermochemical two-step water-splitting cycle requires the development of a high-temperature solar reactor operating at 1000–1500°C. Direct solar energy absorption by metal-oxide particles provides direct efficient heat transfer to the reaction site. This paper describes the experimental results of a windowed small reactor using an internally circulating fluidized bed of reacting metal-oxide particles under direct solar-simulated Xe-beam irradiation. Concentrated Xe-beam irradiation directly heats the internally circulating fluidized bed of metal-oxide particles. NiFe2O4∕m‐ZrO2 (Ni-ferrite on zirconia support) particles are loaded as the working redox material and are thermally reduced by concentrated Xe-beam irradiation. In a separate step, the thermally reduced sample is oxidized back to Ni-ferrite with steam at 1000°C. The conversion efficiency of ferrite reached 44% (±1.0%), which was achieved using the reactor at 1kW of incident Xe lamp power. The effects of preheating temperature and NiFe2O4∕m‐ZrO2 particle size on the performance of the reactor for thermal reduction using an internally circulating fluidized bed were evaluated.

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