The technical pre-feasibility to use briquettes made from wood and agricultural waste for gasification in a downdraft gasifier for electricity generation

2011 ◽  
Vol 22 (4) ◽  
pp. 2-7 ◽  
Author(s):  
Pholoso Malatji ◽  
Ntshengedzeni Sampson Mamphweli ◽  
Martina Meincken
Keyword(s):  
Bulk Density ◽  
Electricity Generation ◽  
Energy Content ◽  
Agricultural Waste ◽  
Fixed Bed ◽  
High Energy ◽  
Residual Moisture ◽  
Waste Products ◽  
Downdraft Gasifier ◽  
Thermochemical Processes

Biomass can be converted to energy through various thermochemical and biological processes. Gasification is one of the thermochemical processes that has recently gained popularity, because it achieves higher conversion efficiencies than, for example, incinerators, boilers or furnaces. Fixed-bed downdraft gasifiers are preferred for electricity generation, because they produce very little tar, but on the other hand, they are limited with regard to biomass properties, such as particle size, bulk density and moisture content. Biomass material with a heterogeneous size is usually processed into pellets or briquettes, which have to be mechanically strong enough to be handled. Cohesive strength is provided by residual moisture and lignin present in most biomass. However, the briquetting process becomes more complicated if one wants to add agricultural waste products that do not necessarily contain lignin as binders. The aim of this work was to process wood chips, grape skins and chicken litter into briquettes that are mechanically stable and have a sufficiently high energy content, as well as adequate bulk density for gasification. The performance of these briquettes in a downdraft gasifier was simulated with a program developed for wood, which was modified to optimise the briquette yield. The results showed a gasification performance comparable to solid pine wood, implying that the blended briquettes could be used as fuel for a downdraft biomass gasifier. Unfortunately, the briquettes proved too instable to experimentally verify the performance in a gasifier. This paper describes the properties of the briquettes as well as the gasification simulation results.

scholarly journals COMBUSTION PERFORMANCE OF SYNGAS FROM PALM KERNEL SHELL IN A GAS BURNER

2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Asmadib Yusoff @ Adnan ◽  
Muhammad Roslan Rahim ◽  
Mohammad Nazri Mohd. Jaafar ◽  
Norazila Othman ◽  
Mohd Shuisma Mohd Ismail ◽  
...  
Keyword(s):  
Alternative Energy ◽  
Energy Content ◽  
Palm Kernel ◽  
High Energy ◽  
Flame Length ◽  
Palm Kernel Shell ◽  
Downdraft Gasifier ◽  
Combustion Performance ◽  
Rich Condition ◽  
Gas Burner

Insufficient and various environmental issues of fossil fuels as the current world dominated energy is now becoming a serious global issue. The rapidly increasing demand for alternative energy sources has contributed to the steady growth of renewable energy. Owing to the fact of the abundant presence of palm kernel shell (PKS) as one of palm biomass wastes in South East Asia region, this paper investigates syngas produced from gasified PKS. The investigation is regarding its composition and combustion performance in a gas burner system. It covers emissions analysis, temperature profile and flame length. The produced syngas from downdraft gasifier was burned in the combustion chamber in air-rich and fuel-rich combustion conditions.  From the experiment, the results showed that the oxidation zone temperature of above 750°C for the downdraft gasifier is suitable for producing syngas. Produced syngas can be classified as pure-carbon monoxide (CO) syngas due to 94.9% CO content with no hydrogen (H2) content and low heating value (LHV) of 10.7 MJ/kg. The wall temperature profiles for burnt syngas produced via downdraft gasification was higher with longer pattern at fuel-rich condition, which signified higher energy of syngas produced from downdraft gasifier compared to fluidised bed gasifier.  The associated flame length was also longer at fuel-rich condition. Produced emission of 56 ppm NOX, 37 ppm CO and 1 ppm SO2 can still be considered as acceptable to human.  It can be concluded that syngas produced from PKS shown a high potential to serve as an alternative source of energy due to its high energy content.

Upgrading of automobile shredder residue via innovative granulation process ‘ReGran’

2016 ◽  
Vol 35 (1) ◽  
pp. 110-119
Author(s):  
Philip Holthaus ◽  
Moritz Kappes ◽  
Wolfgang Krumm
Keyword(s):  
Bulk Density ◽  
Energy Content ◽  
High Energy ◽  
Rotational Frequency ◽  
Regulatory Requirements ◽  
Granulation Process ◽  
Shredder Residue ◽  
Automobile Shredder Residue ◽  
Refuse Derived Fuel ◽  
Interesting Possibility

Stricter regulatory requirements concerning end-of-life vehicles and rising disposal costs necessitate new ways for automobile shredder residue utilisation. The shredder granulate and fibres, produced by the VW-SICON-Process, have a high energy content of more than 20 MJ kg−1, which makes energy recovery an interesting possibility. Shredder fibres have a low bulk density of 60 kg m−3, which prevents efficient storing and utilisation as a refuse-derived fuel. By mixing fibres with plastic-rich shredder granulate and heating the mixture, defined granules can be produced. With this ‘ReGran’ process, the bulk density can be enhanced by a factor of seven by embedding shredder fibres in the partially melted plastic mass. A minimum of 26–33 wt% granulate is necessary to create enough melted plastic. The process temperature should be between 240 °C and 250 °C to assure fast melting while preventing extensive outgassing. A rotational frequency of the mixing tool of 1000 r min−1 during heating and mixing ensures a homogenous composition of the granules. During cooling, lower rotational frequencies generate bigger granules with particles sizes of up to 60 mm at 300 r min−1. To keep outgassing to a minimum, it is suggested to melt shredder granulate first and then add shredder fibres. Adding coal, wood or tyre fluff as a third component reduces chlorine levels to less than 1 wt%. The best results can be achieved with tyre fluff. In combination with the VW-SICON-Process, ReGran produces a solid recovered fuel or ‘design fuel’ tailored to the requirements of specific thermal processes.

scholarly journals Gasification and Power Generation Characteristics of Rice Husk, Sawdust, and Coconut Shell Using a Fixed-Bed Downdraft Gasifier

2021 ◽  
Vol 13 (4) ◽  
pp. 2027
Author(s):  
Md. Emdadul Hoque ◽  
Fazlur Rashid ◽  
Muhammad Aziz
Keyword(s):  
Rice Husk ◽  
Fixed Bed ◽  
Cost Effective ◽  
Coconut Shell ◽  
Energy Sources ◽  
Airflow Rate ◽  
Gas Generation ◽  
Biomass Feedstocks ◽  
Downdraft Gasifier ◽  
Synthetic Gas

Synthetic gas generated from the gasification of biomass feedstocks is one of the clean and sustainable energy sources. In this work, a fixed-bed downdraft gasifier was used to perform the gasification on a lab-scale of rice husk, sawdust, and coconut shell. The aim of this work is to find and compare the synthetic gas generation characteristics and prospects of sawdust and coconut shell with rice husk. A temperature range of 650–900 °C was used to conduct gasification of these three biomass feedstocks. The feed rate of rice husk, sawdust, and coconut shell was 3–5 kg/h, while the airflow rate was 2–3 m3/h. Experimental results show that the highest generated quantity of methane (vol.%) in synthetic gas was achieved by using coconut shell than sawdust and rice husk. It also shows that hydrogen production was higher in the gasification of coconut shell than sawdust and rice husk. In addition, emission generations in coconut shell gasification are lower than rice husk although emissions of rice husk gasification are even lower than fossil fuel. Rice husk, sawdust, and coconut shell are cost-effective biomass sources in Bangladesh. Therefore, the outcomes of this paper can be used to provide clean and economic energy sources for the near future.

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

Autothermal biodrying of municipal solid waste with high moisture content

2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Agnieszka Zawadzka ◽  
Liliana Krzystek ◽  
Stanisław Ledakowicz
Keyword(s):  
Moisture Content ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Energy Content ◽  
Plastic Material ◽  
Initial Moisture Content ◽  
Tubular Reactor ◽  
Calorific Value ◽  
High Energy ◽  
Total Capacity

AbstractTo carry out autothermal drying processes during the composting of biomass, a horizontal tubular reactor was designed and tested. A biodrying tunnel of the total capacity of 240 dm3 was made of plastic material and insulated with polyurethane foam to prevent heat losses. Municipal solid waste and structural plant material were used as the input substrate. As a result of autothermal drying processes, moisture content decreased by 50 % of the initial moisture content of organic waste of about 800 g kg−1. In the tested cycles, high temperatures of biodried waste mass were achieved (54–56°C). An appropriate quantity of air was supplied to maintain a satisfactory level of temperature and moisture removal in the biodried mass and high energy content in the final product. The heat of combustion of dried waste and its calorific value were determined in a calorimeter. Examinations of pyrolysis and gasification of dried waste confirmed their usefulness as biofuel of satisfactory energy content.

scholarly journals Influence of mechanical activation of AL2O3 on synthesis of magnesium aluminate spinel

2004 ◽  
Vol 36 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Zhang Zhihui ◽  
LI. Nan
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Bulk Density ◽  
Milling Time ◽  
High Energy ◽  
Magnesium Aluminate ◽  
Reaction Sintering ◽  
Air Atmosphere ◽  
Energy Ball ◽  
Analytical Reagent

Magnesium aluminate (MA) spinel is synthesized by reaction sintering from alumina and magnesia. The effects of mechanical activation of Al2O3 on reaction sintering were investigated. Non-milled a - Al2O3 and a - Al2O3 high-energy ball milled for 12h, 24h and 36h were mixed with a MgO analytical reagent according to the stoichiometric MA ratio, respectively and pressed into billets with diameters of 20mm and height of 15mm. The green-body billets were then sintered at high temperature in an air atmosphere. The results show that bulk density, relative content of MA and grain size of MA increase with increasing high-energy ball milling time of Al2O3. However prolonged milling time over 24h has a small beneficial effect on the densification of MA. Bulk density and grain size of a sample of a- Al2O3 milled for 24h are 3.30g/cm3 and 4-5 mm, respectively.

Net energy efficiencies of Holstein, Jersey and Holstein-Jersey F1-crosses

2001 ◽  
Vol 72 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. Schwager-Suter ◽  
C. Stricker ◽  
D. Erdin ◽  
N. Künzi
Keyword(s):  
Body Weight ◽  
Body Condition ◽  
Fixed Effects ◽  
Energy Content ◽  
High Energy ◽  
Repeated Measurements ◽  
Low Energy ◽  
Body Tissue ◽  
Net Energy ◽  
Tissue Change

Abstract Net energy efficiencies were calculated from data of an experimental herd with respect to type of cow, lactation number, stage of lactation and diet. The trial consisted of 71 Holstein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses in 1st, 2nd and > 2nd lactation. Data were collected during 210 days of lactation, from calving to week 30 and included total dry matter intake, energy content of foods, milk yield, milk solids, body weight, body condition scores and several body measurements. The cows were divided into four feeding groups : high and low energy content of roughage as well as high and low proportion of concentrates. Net energy efficiency was calculated as the ratio of milk energy to total net energy intake after subtracting energy utilized for maintenance and body tissue change. Body tissue change was calculated either via body-weight changes or body condition-score changes. Due to the distribution of the efficiencies being skewed, efficiencies were transformed applying a Box-Cox transformation. Transformed net energy efficiencies were analysed using a repeated measurements design considering the sequential nature of the observations. Mixed models with a compound symmetry structure for the variance components were applied. Final models contained the fixed effects of type, lactation number, feeding group and the covariates week of lactation and its square. Holstein-Jersey crosses were more efficient than purebreds, second lactation cows were least efficient, cows given low energy roughage and a lower proportion of concentrates were more efficient than cows on the other diets. Least efficient were the cows belonging to the high energy roughage and higher proportion of concentrates group. The coefficients of determination of the final models were between 0·357 and 0·492.

Optimization of a Biomass Micro-Gasification Process for the Production of Synthesis Gas From Palm Shell

2015 ◽  
Author(s):  
Luz M. Ahumada ◽  
Arnaldo Verdeza ◽  
Antonio J. Bula
Keyword(s):  
Particle Size ◽  
Fixed Bed ◽  
High Energy ◽  
Operating Conditions ◽  
Air Velocity ◽  
Output Variable ◽  
Heating Value ◽  
Palm Shell ◽  
Gasification Process ◽  
Air Speed

This paper studied, through an experiment design, the significance of particle size, air speed and reactor arrangement for palm shell micro-gasification process in order to optimize the heating value of the syngas obtained. The range of variables was 8 to 13 mm for particle size, 0.8–1.4m/s for air velocity, and updraft or downdraft for the reactor type. It was found that the particle size and air velocity factors were the most significant in the optimization of the output variable, syngas heating value. A heating value of 2.69MJ / Nm3 was obtained using a fixed bed downdraft reactor, with a particle size of 13 mm and 1.4 m/s for air speed; verification of the optimum point of operation under these conditions verified that these operating conditions favor the production of a gas with a high energy value.

Hydrogen Generation in an Annular Micro-Reactor: an Experimental Investigation of Water Splitting Reaction Using Aluminum in Presence of Potassium Hydroxide

2018 ◽  
Vol 17 (2) ◽  
Author(s):  
Shyam P. Tekade ◽  
Diwakar Z. Shende ◽  
Kailas L. Wasewar
Keyword(s):  
Water Splitting ◽  
Potassium Hydroxide ◽  
Hydrogen Generation ◽  
Energy Content ◽  
Average Rate ◽  
High Energy ◽  
Low Flow ◽  
Flow Rates ◽  
Metal Aluminum ◽  
Micro Reactor

Abstract Hydrogen is one of the important non-conventional energy sources because of its high energy content and non-polluting nature of combustions. The water splitting reaction is one of the significant methods for hydrogen generation from non-fossil feeds. In the present paper, the hydrogen generation has been experimentally investigated with water splitting reaction using metal aluminum in presence of potassium hydroxide as an activator under flow conditions. The rate of hydrogen generation was reported in the annular micro- reactor of 1 mm annulus using various flow rates of aqueous 0.5 N KOH ranging from 1 ml/min to 10 ml/min. The complete conversion of aluminum was observed at all the flow rates of aqueous KOH. The hydrogen generation rate was observed to depend on the flow rate of liquid reactant flowing through the reactor. At 1 ml/min of 0.5 N KOH, hydrogen generates at an average rate of 3.36 ml/min which increases to 10.70 ml/min at 10 ml/min of aqueous KOH. The Shrinking Core Model was modified for predicting the controlling mechanism. The rate of hydrogen generation was observed to follow different controlling mechanisms on various time intervals at low flow rates of aqueous KOH. It was observed that chemical reaction controls the overall rate of hydrogen generation at higher flow rates of aqueous KOH.

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