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.

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.

NOx and N2O Emission Formation Tendency From Multifuel CFB-Boilers: A Further Development of the Predictor

2005 ◽  
Author(s):  
Markus Engblom ◽  
Pia Kilpinen ◽  
Fredrik Klingstedt ◽  
Kari Era¨nen ◽  
Ranjit Katam Kumar
Keyword(s):  
Nitrogen Oxides ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Wood Pellets ◽  
Char Particle ◽  
Technical University ◽  
Fuel Mixtures

Present paper is a part of our on-going model development activities with aim to predict formation tendency of gaseous emissions from CFB combustion of different fuels, and especially, fuel-mixtures in real furnaces of various scale. The model is based on detailed description of homogeneous, catalytic, and heterogeneous chemical kinetics, and a sound but simple 1.5D representation of fluid dynamics. Temperature distribution is assumed known. With the tool, different fuels and fuel mixtures can be compared in respect to their tendency to form nitrogen oxides (NOx, N2O). In this paper the model was tested to predict nitrogen oxide emissions from mono- or co-combustion of coal, wood, and sludge. The plants simulated were the 12MWth CFB combustor located at Chalmers Technical University (A = 2.25m2, h = 13.6m) and the pilot scale CFB unit at the Technical University Hamburg-Harburg (d = 0.1m, h = 15m). The results gave reasonable representation of the measured emission data, and reflected correctly to the changes in the fuel characteristics and in the furnace operating conditions in most cases. An extensive laboratory fixed-bed reactor study was also performed in order to obtain input values for the kinetic constants of the catalytic reactions for the reduction and decomposition of nitrogen oxides. In literature, there is a limited data available regarding the catalytic activity of CFB solids during combustion of wood- and waste-derived fuels, especially at co-firing conditions. The kinetics for the NO reduction by CO in the temperature range of 780–910°C was determined to be of the following form (NO = 300ppm, CO = 5000ppm): −rNO=k·[NO]0.48·[CO]0.55mol/g-s with k=8.15·exp(−8869/T)m3/kg-s(emptyreactoreffectincluded)ork=830·exp(−14930/T)(emptyreactoreffectexcluded), when using a bed sample (250–355 μm) taken from the transport zone in the CTH boiler while burning a mixture of wood pellets and a pre-dried municipal sewage sludge. The role of char particle size and shape as well as the incorporation of energy balance on the char reactivity and the formation of nitrogen oxides is further illustrated by single char particle oxidation simulations.

Study of the reaction front thickness in a counter-current fixed-bed combustor of a pelletised biomass

2012 ◽  
Vol 159 (3) ◽  
pp. 1296-1302 ◽  
Author(s):  
Jacobo Porteiro ◽  
David Patiño ◽  
Jose L. Miguez ◽  
Enrique Granada ◽  
Jorge Moran ◽  
...  
Keyword(s):  
Reaction Front ◽  
Fixed Bed ◽  
Counter Current

scholarly journals Experimental Studies on Wood Pellets Combustion in a Fixed Bed Combustor Using Taguchi Method

Fuels ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 376-392
Author(s):  
Carlos Castro ◽  
Lelis Fraga ◽  
Eduardo Ferreira ◽  
Jorge Martins ◽  
Pedro Ribeiro ◽  
...  
Keyword(s):  
Taguchi Method ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Wood Pellets ◽  
Split Ratio ◽  
Excess Air ◽  
Bed Temperature ◽  
Secondary Air ◽  
Co Reduction ◽  
Co Emission

The combustion of wood pellets in a fixed bed combustor of a 20 kW capacity domestic pellet boiler was tested according to several factors including Power, Excess Air (EA), Primary/Secondary air Split Ratio (SR) and Grate Area (GA). The Taguchi method was applied to program the experimental design. Several parameters were measured, including gas emissions (CO), fuel bed temperature (measured at 4 different heights), and efficiency. The experimental results show that the lower CO emission and the higher efficiency were obtained at medium thermal loads and the highest temperature on the fuel bed was obtained at about ¼ of its height (15 mm). The results obtained from the analysis of variance (ANOVA) show that the SR and the Power are the most important factors contributing to the CO reduction and also increase the fuel bed temperature.

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.

Enhanced Yield of Hydrogen From Wastes Using High Temperature Steam Gasification

2005 ◽  
Vol 128 (3) ◽  
pp. 179-185 ◽  
Author(s):  
W. Jangsawang ◽  
A. Klimanek ◽  
Ashwani K. Gupta
Keyword(s):  
Carbon Monoxide ◽  
Fixed Bed ◽  
Calculated Data ◽  
Steam Gasification ◽  
Fixed Bed Reactor ◽  
Effect Of Temperature ◽  
Gas Composition ◽  
Wood Pellets ◽  
Feed Composition ◽  
High Yields

Equilibrium calculations using the element potential method have been used to determine optimum conditions for the gasification of wood pellets and to understand the limitations and influence of preheated gasifying agent on the product gas composition. The calculations were carried out under isobaric (1 atm) and isothermal conditions using cellulose as the waste fuel. For each isothermal case results were obtained for the effect of feed gas composition. Various mixtures of steam/cellulose [mol/mol] and oxygen/steam [mol/mol] were examined to determine conditions for high yields of H2 and CO at a given temperature. The yield of hydrogen and carbon monoxide with different input feed composition and temperature of the process are therefore considered. The results showed strong effect of temperature on hydrogen and carbon monoxide yield in the gasified product stream. High temperatures resulted in high yields of hydrogen. Pure steam resulted in higher yields of hydrogen than steam-air gasifying agent. The experimental results using a fixed bed reactor showed good trends with the calculated data. These results assist in the design and development of enhanced hydrogen production from steam gasification of wastes.

scholarly journals Oxidative pyrolysis of wood chips and of wood pellets in a downdraft continuous fixed bed reactor

Fuel ◽  
2017 ◽  
Vol 196 ◽  
pp. 408-418 ◽  
Author(s):  
Elias Daouk ◽  
Laurent Van de Steene ◽  
Frederic Paviet ◽  
Eric Martin ◽  
Jeremy Valette ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Wood Chips ◽  
Fixed Bed Reactor ◽  
Wood Pellets ◽  
Oxidative Pyrolysis
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