Numerical Reconstruction of the Catalyst Bed Temperature Distribution in a Multitubular Fixed-Bed Reactor by Karhunen–Loève Expansion

2013 ◽  
Vol 52 (23) ◽  
pp. 7818-7826 ◽  
Author(s):  
Jie Fu ◽  
Rongchun Shen ◽  
Zhongming Shu ◽  
Xinggui Zhou ◽  
Weikang Yuan
Keyword(s):  
Temperature Distribution ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Numerical Reconstruction ◽  
Bed Temperature

Slow Pyrolysis of Cystoseira Barbata Brown Macroalgae

2018 ◽  
Vol 69 (3) ◽  
pp. 553-556 ◽  
Author(s):  
Doinita Roxana Cioroiu ◽  
Oana Cristina Parvulescu ◽  
Tanase Dobre ◽  
Cristian Raducanu ◽  
Claudia Irina Koncsag ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Heat Flow Rate ◽  
Slow Pyrolysis ◽  
Process Factor ◽  
Bed Temperature ◽  
Cystoseira Barbata ◽  
Bio Oil

Slow pyrolysis of algal biomass of Cystoseira barbata was performed in a fixed bed reactor using carbon dioxide as a sweeping gas and a reactant in the process. Pyrolysis products consisted of a biochar, a bio-oil, and pyrolytic gases. According to a 23 factorial experiment, 8 tests were conducted for 1 hr at two levels of each process factor, i.e., specific heat flow rate (7540, 9215 W/m3), carbon dioxide superficial velocity (1.3, 2.6 cm/s), and bulk density of fixed bed biomass (221, 332 kg/m3). Correlations between these factors and final process responses in terms of mean bed temperature (461-663 oC), biochar yield (15.2-26.7%), bio-oil yield (29.9-34.8%), and BET surface area of biochar (45.17-91.12 m2/g) were established.

scholarly journals Investigation of the Olive Mill Solid Wastes Pellets Combustion in a Counter-Current Fixed Bed Reactor

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1965 ◽  
Author(s):  
Mohamed Mami ◽  
Hartmut Mätzing ◽  
Hans-Joachim Gehrmann ◽  
Dieter Stapf ◽  
Rainer Bolduan ◽  
...  
Keyword(s):  
Reaction Front ◽  
Mass Loss Rate ◽  
Fixed Bed ◽  
Solid Wastes ◽  
Fixed Bed Reactor ◽  
Electricity Production ◽  
Wood Pellets ◽  
Bed Temperature ◽  
Counter Current ◽  
Olive Mill

Combustion tests and gaseous emissions of olive mill solid wastes pellets (olive pomace (OP), and olive pits (OPi)) were carried out in an updraft counter-current fixed bed reactor. Along the combustion chamber axis and under a constant primary air flow rate, the bed temperatures and the mass loss rate were measured as functions of time. Moreover, the gas mixture components such as O2, organic carbon (Corg), CO, CO2, H2O, H2, SO2, and NOx (NO + NO2) were analyzed and measured. The reaction front positions were determined as well as the ignition rate and the reaction front velocity. We have found that the exhaust gases are emitted in acceptable concentrations compared to the combustion of standard wood pellets reported in the literature (EN 303-5). It is shown that the bed temperature increased from the ambient value to a maximum value ranging from 750 to 1000 °C as previously reported in the literature. The results demonstrate the promise of using olive mill solid waste pellets as an alternative biofuel for heat and/or electricity production.

Temperature Distribution Near a Heat Exchanger Wall Immersed in High-Temperature Packed and Fluidized Beds

1992 ◽  
Vol 114 (1) ◽  
pp. 50-55 ◽  
Author(s):  
G. Flamant ◽  
N. Fatah ◽  
G. Olalde ◽  
D. Hernandez
Keyword(s):  
Temperature Distribution ◽  
Fluidized Beds ◽  
Solid Phase ◽  
Particle Temperature ◽  
Fixed Bed ◽  
Temperature Fields ◽  
Gas Temperature ◽  
Bed Temperature ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Experimental results dealing with both particle and gas temperature distribution in the vicinity of a water-cooled wall immersed in fixed and fluidized beds are presented. The measurement of particle temperature is based on the use of a mobile optical fiber connected to a two-color radiometer. The gas temperature is obtained on the basis of the indications of a bare thermocouple. Particle and gas temperature fields are compared in fixed and fluidized beds for alumina and silicon carbide particles. In the fixed bed, temperature differences as large as 300°C between the gas and the solid are measured. In the fluidized bed, temperature decreases of both solid and gas phase are shown for large particle at incipient fluidization. The temperature variation reaches more than 100°C for corundum particles and 200°C in the gas. The temperature distribution in the solid phase is shown to be dependent on the thermophysical properties of the particles (thermal conductivity and emissivity).

Steam Gasification of Catalytic Pyrolysis Char for Hydrogen-Rich Gas Production

2013 ◽  
Vol 316-317 ◽  
pp. 105-108
Author(s):  
Wu Xing Sun ◽  
Yan Zhou ◽  
Qi Wang ◽  
Shu Rong Wang
Keyword(s):  
Atmospheric Pressure ◽  
Catalytic Pyrolysis ◽  
Fixed Bed ◽  
Gas Production ◽  
Steam Gasification ◽  
Fixed Bed Reactor ◽  
Bed Temperature ◽  
Production Of Hydrogen ◽  
Pyrolysis Of Biomass ◽  
Gasification Temperature

Steam gasification of biochar from catalytic pyrolysis of biomass was studied in a fixed bed reactor at atmospheric pressure. The experiments were carried out at bed temperature of 700, 750, 800 °C at steam flow rate of 0.1 g/min with reaction time of 3h. The gases produced included mainly H2, CO, CO2 and some small molecular hydrocarbons. The results showed that high gasification temperature was favorable for the production of hydrogen-rich gases. The maximum concentration of hydrogen exceeded 85% at 800 °C and the total gas yield increased with temperature rising. Meanwhile, the conversion efficiency of biochar at 700, 750, 800 °C was 48%, 60%, 72% respectively.

Simulation of Fixed Bed Reactor for the Dehydration Reaction from Alcohol Gas to Ethylene

2014 ◽  
Vol 910 ◽  
pp. 123-126 ◽  
Author(s):  
Ying Tao Song ◽  
Ming Yan Dang
Keyword(s):  
Temperature Distribution ◽  
Fixed Bed ◽  
Axial Direction ◽  
Fixed Bed Reactor ◽  
Outlet Temperature ◽  
Target Product ◽  
Dehydration Reaction ◽  
Gas Velocity ◽  
Reaction Characteristics ◽  
Radial Heat

A numerical model has been established and solved to describe the dehydration reaction from alcohol to ethylene. The influences of the gas velocity and the temperature of the feeding gas to the process of the reaction were discussed. The results showed that, the influence of the radial diffusion on the reaction characteristics could be ignored while the influence of radial heat conduction to the temperature distribution was significant. The temperature distribution decreased alone the axial direction at first and then increased, that is a lowest point of the temperature could be found. When the velocity of the gas slowed down or the temperature of the feeding gas increased, the conversion of the reactant and the selectivity of the target product could be improved, the distance of the lowest temperature point to the entrance got closer and the outlet temperature became higher.

scholarly journals Thermal Degradation of Cassava Rhizome in Thermosyphon-Fixed Bed Torrefaction Reactor

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 267 ◽  
Author(s):  
Nitipong Soponpongpipat ◽  
Suwat Nanetoe ◽  
Paisan Comsawang
Keyword(s):  
Temperature Distribution ◽  
Fixed Bed ◽  
Decomposition Reaction ◽  
Fixed Bed Reactor ◽  
Energy Yield ◽  
Mass Yield ◽  
The Difference ◽  
Laboratory Reactor ◽  
Decomposition Behavior ◽  
Purge Gas

A thermosyphon-fixed bed reactor was designed and constructed to investigate the temperature distribution of the cassava rhizome and its decomposition behavior. To study the properties of torrefied char obtained from this reactor, cassava rhizome was torrefied in five different configurations, including the thermosyphon-fixed bed reactor, a laboratory reactor in compact bulk arrangement with N2 as the purge gas and without any purge gas, and another one in a hollow bulk arrangement with and without purge gas. It was found that the use of thermosyphons with a fixed bed reactor improved the uniform temperature distribution. The average heating rate to the cassava rhizome bed was 1.40 °C/min, which was 2.59 times higher than that of the fixed bed reactor without thermosyphons. Compared to the other configurations, this reactor gave the highest higher heating value (HHV) and the lowest mass yield of 23.97 MJ/kg and 47.84%, respectively. The water vapor produced in this reactor played an autocatalyst role in the decomposition reaction. Finally, the thermosyphon-fixed bed reactor gave an energy yield in the range of 70.43% to 86.68%. The plot of the HHV ratio–mass yield diagram indicated the difference of torrefied char obtained from different reactors. The thermosyphon-fixed bed reactor produced torrefied biomass with the highest HHV ratio compared to that of other reactors at the same energy yield.

scholarly journals Valorization of Vine Prunings by Slow Pyrolysis in a Fixed-Bed Reactor

Processes ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Suzana Ioana Calcan ◽  
Oana Cristina Pârvulescu ◽  
Violeta Alexandra Ion ◽  
Cristian Eugen Răducanu ◽  
Liliana Bădulescu ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Pyrolysis Product ◽  
Fixed Bed Reactor ◽  
Slow Pyrolysis ◽  
23 Factorial Design ◽  
Bed Temperature ◽  
Bio Oil ◽  
Mean Size ◽  
Ft Ir ◽  
Water Holding

The paper aimed at studying the slow pyrolysis of vine pruning waste in a fixed bed reactor and characterizing the pyrolysis products. Pyrolysis experiments were conducted for 60 min, using CO2 as a carrier gas and oxidizing agent. The distribution of biochar and bio-oil was dependent on variations in heat flux (4244–5777 W/m2), CO2 superficial velocity (0.004–0.008 m/s), and mean size of vegetal material (0.007–0.011 m). Relationships among these factors and process performances in terms of yields of biochar (0.286–0.328) and bio-oil (0.260–0.350), expressed as ratio between the final mass of pyrolysis product and initial mass of vegetal material, and final value of fixed bed temperature (401.1–486.5 °C) were established using a 23 factorial design. Proximate and ultimate analyses, FT-IR and SEM analyses, measurements of bulk density (0.112 ± 0.001 g/cm3), electrical conductivity (0.55 ± 0.03 dS/m), pH (10.35 ± 0.06), and water holding capacity (58.99 ± 14.51%) were performed for biochar. Water content (33.2 ± 1.27%), density (1.027 ± 0.014 g/cm3), pH (3.34 ± 0.02), refractive index (1.3553 ± 0.0027), and iodine value (87.98 ± 4.38 g I2/100 g bio-oil) were measured for bio-oil. Moreover, chemical composition of bio-oil was evaluated using GC-MS analysis, with 27 organic compounds being identified.

Sign in / Sign up

Export Citation Format

Share Document