scholarly journals Thermal and Torrefaction Characteristics of a Small-Scale Rotating Drum Reactor

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 489
Author(s):  
Nitipong Soponpongpipat ◽  
Suwat Nanetoe ◽  
Paisan Comsawang
Keyword(s):  
Heat Loss ◽  
Small Scale ◽  
Reactor Wall ◽  
Energy Yield ◽  
Exhaust Gas ◽  
Mass Yield ◽  
Rotating Drum ◽  
Reactor Types ◽  
Purge Gas ◽  
Rotating Drum Reactor

The small-scale rotating drum reactor (SS-RDR) was designed and constructed without using purge gas for the purpose of household application. The thermal and torrefaction characteristics of SS-RDR were studied and compared with other reactor types. It was found that the heat loss at the reactor wall and heat loss from exhaust gas of the SS-RDR were in the range of 6.3–12.4% and 27.9–42.8%, respectively. The increase of flue gas temperature resulted in the decrease of heat loss at the reactor wall and the increase of heat loss from exhaust gas. The heating rate of the SS-RDR was in the range of 7.3–21.4 °C/min. The higher heating value (HHV) ratio, mass yield, and energy yield ofthe SS-RDR were in the range of 1.2–1.6, 35.0–81.0%, and 56.2–96.5%, respectively. A comparison of torrefaction characteristics of various reactor types on HHV ratio-mass yield-iso-energy yield diagram indicated that the torrefaction characteristics of the SS-RDR were better than that of the rotating drum reactor with purge gas.

Effects of Reactor Design on the Torrefaction of Biomass

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Alok Dhungana ◽  
Prabir Basu ◽  
Animesh Dutta
Keyword(s):  
Energy Density ◽  
Fluidized Beds ◽  
Process Conditions ◽  
Convective Heating ◽  
Energy Yield ◽  
Mass Yield ◽  
Rotating Drum ◽  
Volumetric Heating ◽  
Direct Heating ◽  
Common Basis

Torrefied biomass is a green alternative to coal, and thus the interest in the torrefaction process is rising fast. Different manufacturers are offering different patented designs of torrefier with data on varying operating and process conditions each claiming their superiority over others. The choice of torrefaction technology has become exceptionally difficult because of a near absence of a comparative assessment of different types of reactors on a common base. This work attempts to fill this important knowledge gap in torrefaction technology by reviewing available types of reactors, and comparing their torrefaction performance common basis and examining the commercial implication of reactor choice. After reviewing available patent and technologies offered, torrefiers are classified broadly under two generic groups: indirectly heated and directly heated. Four generic types of reactors, convective heating, fluidized bed, rotating drum and microwave reactor were studied in this research. Convective and fluidized beds have direct heating, rotating reactors has indirect heating while microwave involves a volumetric heating (a subgroup of direct heating) mechanism. A standard sample of biomass (25 mm diameter × 64 mm long poplar wood) was torrefied in each of these types of reactors under identical conditions. The mass yield, energy density and energy yield of the wood after torrefaction were measured and compared. Rotating drum achieved lowest mass yield but highest energy density. The difference between two direct heating, convective heating and fluidized beds was small. Microwave provided only localized torrefaction in this series of tests. Indirectly heated reactors might be suitable for a plant near the biomass source while directly heated plant would give better value at the user end.

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 Maize intercropping in the milpa system. Diversity, extent and importance for nutritional security in the Western Highlands of Guatemala

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Santiago Lopez-Ridaura ◽  
Luis Barba-Escoto ◽  
Cristian A. Reyna-Ramirez ◽  
Carlos Sum ◽  
Natalia Palacios-Rojas ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Farm Households ◽  
Small Scale ◽  
Agricultural System ◽  
Energy Yield ◽  
Common Beans ◽  
Nutritional Security ◽  
Nutrient Adequacy ◽  
Faba Beans ◽  
Total Productivity

AbstractWe present an assessment of the extent, diversity, and nutritional contribution of the milpa through a quantitative analysis of data from a survey conducted in 989 small scale farm households in the Western Highlands of Guatemala (WHG). The milpa is a traditional agricultural system in which maize is intercropped with other species, such as common beans, faba beans, squashes or potatoes. Our study shows that more than two-thirds of the 1,205 plots recorded were under the milpa system, with a great diversity of crop combinations. As shown with the 357 plots for which specific yields were available, milpa systems present higher total productivity than monocropped maize, expressed as total energy yield of the harvested crops in the respective system, and were also better at providing the recommended daily allowances of fourteen essential nutrients, based on a Potential Nutrient Adequacy (PNA) indicator. Maize-bean-potato, maize-potato, and maize-bean-faba intercrops had the highest PNAs, and monocropped maize, the lowest. These results support the implementation of milpa systems tailored to different agro-ecologies in order to improve nutrition in the WHG and a variety of similar regions.

Shifting of the flame front in a small-scale commercial downdraft gasifier by water injection and exhaust gas recirculation

Fuel ◽  
2021 ◽  
Vol 303 ◽  
pp. 121297
Author(s):  
A. Zachl ◽  
M. Buchmayr ◽  
J. Gruber ◽  
A. Anca-Couce ◽  
R. Scharler ◽  
...  
Keyword(s):  
Flame Front ◽  
Water Injection ◽  
Exhaust Gas Recirculation ◽  
Small Scale ◽  
Exhaust Gas ◽  
Downdraft Gasifier ◽  
Gas Recirculation

scholarly journals Triggering avalanches by transverse perturbations in a rotating drum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vicente Salinas ◽  
Cristóbal Quiñinao ◽  
Sebastián González ◽  
Gustavo Castillo
Keyword(s):  
Hopf Bifurcation ◽  
Theoretical Model ◽  
Order Parameter ◽  
Small Scale ◽  
Rotating Drum ◽  
Governing Parameter ◽  
Stick Slip ◽  
Slip Regime ◽  
Axis Of Rotation

AbstractWe study the role of small-scale perturbations in the onset of avalanches in a rotating drum in the stick-slip regime. By vibrating the system along the axis of rotation with an amplitude orders of magnitude smaller than the particles’ diameter, we found that the order parameter that properly describes the system is the kinetic energy. We also show that, for high enough frequencies, the onset of the avalanche is determined by the amplitude of the oscillation, contrary to previous studies that showed that either acceleration or velocity was the governing parameter. Finally, we present a theoretical model that explains the transition between the continuous and discrete avalanche regimes as a supercritical Hopf bifurcation.

Research and Improvement on Calculation Method of Optimal Excess Air Ratio

2014 ◽  
Vol 536-537 ◽  
pp. 1583-1586
Author(s):  
Jun Xiong Qi
Keyword(s):  
Heat Loss ◽  
Correction Factor ◽  
Calculation Method ◽  
Traditional Method ◽  
Combustion Efficiency ◽  
Exhaust Gas ◽  
Incomplete Combustion ◽  
Excess Air

By analyzing the relations of the excess air ratio to heat loss due to exhaust gas, chemical incomplete combustion and combustibles in refuse, the traditional method for solving the optimal excess air ratio is improved. A correction factor is proposed for heat loss due to combustibles in refuse, making the solving method more accurate, which is of great importance for improving the combustion efficiency of the boiler.

scholarly journals Experimental Study on Hydrothermal Carbonization of Lignocellulosic Biomass with Magnesium Chloride for Solid Fuel Production

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 444 ◽  
Author(s):  
Samuel Carrasco ◽  
Javier Silva ◽  
Ernesto Pino-Cortés ◽  
Jaime Gómez ◽  
Fidel Vallejo ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Solid Fuel ◽  
Magnesium Chloride ◽  
Calorific Value ◽  
Hydrothermal Carbonization ◽  
Volatile Matter ◽  
Matter Content ◽  
Operating Conditions ◽  
Energy Yield ◽  
Mass Yield

The effect of magnesium chloride as an additive of hydrothermal carbonization (HTC) of lignocellulosic biomass (Pinus radiata sawdust) was studied. The HTC tests were carried out at fixed conditions of temperature and residence time of 220 °C and 1 h, respectively, and varying the dose of magnesium chloride in the range 0.0–1.0 g MgCl2/g biomass. The carbonized product (hydrochar) was tested in order to determine its calorific value (HHV) while using PARR 6100 calorimeter, mass yield by gravimetry, elemental analysis using a LECO TruSpec elemental analyzer, volatile matter content, and ash content were obtained by standardized procedures using suitable ovens for it. The results show that using a dose of 0.75 g MgCl2/g biomass results in an impact on the mass yield that was almost equal to change operating conditions from 220 to 270 °C and from 0.5 to 1 h, without additive. Likewise, the calorific value increases by 33% for this additive dose, resulting in an energy yield of 68%, thus generating a solid fuel of prominent characteristics.

scholarly journals Experimental Investigation of Discoloration Generated by a CI ICE's Exhaust Gas on Various Stone Types

2018 ◽  
Vol 46 (3) ◽  
pp. 158-163 ◽  
Author(s):  
Orsolya Farkas ◽  
György Szabados ◽  
Ákos Antal ◽  
Ákos Török
Keyword(s):  
Particulate Matter ◽  
Construction Materials ◽  
Exhaust System ◽  
Mass Effect ◽  
Small Scale ◽  
Exhaust Gas ◽  
Colour Measurement ◽  
Compression Ignition Engine ◽  
Before And After ◽  
The One

The effect of particulate matter - as a component of an internal combustion engine's exhaust gas - on 8 different types of construction materials have been studied under laboratory conditions. Our aim was double. On the one hand it was to investigate the degree of discolouration, whether there is a difference between the 8 types of rock in the same exposure, after laboratory contamination. On the other hand to measure the mass effect of particulate on the rocks. For testing the adverse effects of diesel soot and particulate matter on stones a small scale laboratory exposure chamber was constructed and built in the exhaust system of the engine. A compression ignition engine was used to pollute directly the set of stones. Mass and colour measurement tests have been carried out on the stones before and after the exposure. The result is as expected small difference in the mass properties and a greater changes in terms of colour measurement.

The Staged Thermal Conversion of Sewage Sludge in the Presence of Oxygen

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Halina Pawlak-Kruczek ◽  
Mateusz Wnukowski ◽  
Krystian Krochmalny ◽  
Mateusz Kowal ◽  
Marcin Baranowski ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Sewage Sludge ◽  
Thermal Processing ◽  
Thermal Conversion ◽  
Single Step ◽  
Energy Yield ◽  
Mass Yield ◽  
Optimal Conditions ◽  
Kinetics Of ◽  
By Products

This study compares a staged thermal processing of the sewage sludge, with single step, integrated thermal processing. The aim of this study is to find the optimal conditions for drying and subsequently for carbonization/torrefaction of sewage sludge, regarding the energy consumption. This study presents the results of the drying tests performed at laboratory scale convective dryer for different parameters of drying agent (air). The tests were focused on finding and developing a method of drying that allows to minimize the energy consumption. Subsequently, both dry and vapothermal torrefaction was performed in the presence of oxygen. The kinetics of drying, using low quality heat as well as the properties of products and by-products of torrefaction in both regimes were determined. The process was characterized by mass yield and energy yield in both of the cases. There has been only scarce amount of literature studies published on the torrefaction of sewage sludge so far, without a detailed study of the composition of the torgas and tars of such origin. Performed study enables a comparison of two distinct scenarios of the processing, i.e., drying followed by dry torrefaction with a single stage of vapothermal torrefaction.

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