scholarly journals Development of a Hammer Mill with Double Sieving Screens

2020 ◽  
Vol 5 (5) ◽  
pp. 617-621
Author(s):  
Oluyemisi Adebanjo Ojomo ◽  
A. J. Fawohunre
Keyword(s):  
Moisture Content ◽  
Specific Energy ◽  
Energy Requirement ◽  
Hammer Mill ◽  
Performance Indices ◽  
Dual Purpose ◽  
Specific Energy Requirement ◽  
Level Of Significance ◽  
Machine Speed ◽  
The Relationship

A hammer mill with double sieving device was designed and fabricated from locally available materials for grinding grains and other agricultural products. The conceptual design was based on the principle of design by analysis. The test carried out on the machine showed that the crushing capacity of the machine is 51.5 Kh/hr. The moisture content, machine speed and the interaction between them had significant effect on the milling power and specific energy requirement at 5 % level of significance. Milling power and specific energy requirement of the machine increased with increase in moisture content. The maximum crushing efficiency of 79.3 %, minimum milling power and specific energy requirement of 0.09 Kw and 3.04 Kwh/mg respectively were obtained at moisture content of 8 % (wb) and machine speed of 2000 rpm. Regression models that could be used to express the relationship existing between the hammer mill performance indices, product moisture content and machine speed were established. The machine has dual purpose for either electric motor or petrol engine.

Energetic relationships for crushing of soil clods

2006 ◽  
Vol 2 (1) ◽  
pp. 51-72
Author(s):  
István Patay ◽  
Virág Sándor
Keyword(s):  
Moisture Content ◽  
Specific Energy ◽  
Soil Moisture Content ◽  
Energy Requirement ◽  
Clay Content ◽  
Clay Soils ◽  
Rigid Support ◽  
Soil Plasticity ◽  
Specific Energy Requirement ◽  
The Relationship

Clod crushing is a principal problem with soils of high clay content. Therefore, there is a need for determining the conditions for clod breaking and clod crushing. The objective of the work was to develop a special purpose tool for single clod breaking both by rigid support of the clod and by a single clod supported by soil and to develop a machine for clod crushing. Furthermore, the purpose was to determine the relationship between the specific energy requirement for clod crushing in the function of soil plasticity and the soil moisture content by the means of the developed tool and machine. The main result of the experiments is summarized in a 3D diagram where the specific energy requirement for soil clod crushing is given in the function of the moisture content and the plasticity index for different clay soils.

scholarly journals DEVELOPMENT OF WOOD GRINDING. 3. FURTHER TESTING OF GRINDING MODELS

2021 ◽  
Vol 55 (7-8) ◽  
pp. 795-797
Author(s):  
BRUNO LÖNNBERG
Keyword(s):  
Energy Balance ◽  
Moisture Content ◽  
Specific Energy ◽  
Energy Requirement ◽  
Wood Properties ◽  
Wood Moisture Content ◽  
Critical Examination ◽  
Stone Surface ◽  
Wood Moisture ◽  
Specific Energy Requirement

"The study is the continuation of a sequence of works devoted to describing the mechanisms occurring during stone grinding of wood. This part was aimed at further testing of pressurised grinding of spruce wood, which was conducted under controlled laboratory conditions. Testing of the developed theoretical model for power ratio (Pc/Pt) versus energy specific production (Ġw/Pt) produced linears for data representing constant wood moisture content. However, the linears showed almost identical results for fresh woods, and also for drier wood, e.g. wood containing saturated fibres and air-dried wood, although one would expect some differences due to the widely varying constant moisture, from 65% to 15% moisture content. Simplification of the model resulted in (cw + X cm) ΔTp-w ≈ Pt / Ġw, and it led to specific linears, when the members as such were correlated between themselves at several constant wood moisture contents. The results were briefly as follows. Increasing wood feed rate – 0.7, 1.0 and 1.3 mm/s – decreased the specific energy requirement, while increased stone surface speed – 20 and 30 m/s – increased it. The left-hand member or the “X-factor” as named in this context, correlated with the right-hand member or the specific energy requirement and resulted in declining linears. The lower the wood moisture content – 65, 58, 44, 28 and 15% – the smaller was the linear declination, and also the difference due to stone surface speed. The application of an energy balance could be useful in searching for a working wood grinding model. Such a model would enable critical examination of wood grinding conditions. Also, it would help understanding the mechanism of various factors, such as grinding parameters, wood properties and stone burr and sharpness. It seems that there are factors that are not known well enough for further development of grinding. Shower water flow and temperature affect the stone surface temperature as known, but their significance for the energy balance or grinding mechanism are not known. Also, the thin film of pulp slurry between the stone surface and the heat activated wood layer is evidently a significant factor that is connected to the local energy transfer. "

Convective and microwave drying characteristics, energy requirement and color retention of dehydrated nettle leaves (Urtica diocia L.)

2017 ◽  
Author(s):  
Fuat Lule ◽  
Turhan Koyuncu
Keyword(s):  
Moisture Content ◽  
Air Temperature ◽  
Energy Requirement ◽  
Color Difference ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Color Retention ◽  
Specific Energy Requirement

In this research, convective and microwave drying characteristics, energy requirement and color changes of nettle leaves (Urtica diocia L.) were reported. Samples of freshly harvested nettle leaves were dehydrated under three air temperatures of 50 °C, 60 °C and 70 °C and at three microwave power levels of PL-1, PL-2 and PL-3. Selected drying air velocity was 0.30 m/s for all temperatures. This is coming from the fact that it was understood from the preliminary studies that the temperature less than 50 °C and the air speed more than 0.30 ms-1 increase the drying time and energy requirement, extremely for these products. Nettle leaves were dehydrated from the initial moisture content of 320 (percentage dry basis) to a final moisture content of 7 % to 9 %. During convective drying experiments, product were weighted automatically by the balance per (5 to10) min. Data were transferred to the computer and processed by a software. During microwave drying, the product were weighted and data recorded manually per (15 to 60) min. The influence of drying method, drying air temperature and microwave power level have also been studied. Hunter L, a, b values system was also used to evaluate changes in total color difference (DE) on dried products. The results showed that convective drying air temperature and microwave oven power levels influenced the total drying time, total energy requirement, specific energy requirement and color difference for nettle leaves. The minimum specific energy requirement were determined as 6.95 kWhkg-1 and 23.63 kWhkg-1 for 70 °C and PL-2 respectively. 70 °C drying air temperature and PL-3 was found to yield better quality product in terms of color retention of Hunter L, a, b and DE. As a result, to reduce drying energy consumption and to keep better color retention, convective drying can be recommended for this application.

Specific Energy Requirement for Compacting Corn Cobs

2010 ◽  
Vol 148-149 ◽  
pp. 245-252
Author(s):  
Zhi Qiang Jin ◽  
Shun Xi Wang
Keyword(s):  
Particle Size ◽  
Specific Energy ◽  
Energy Requirement ◽  
Linear Regression Analysis ◽  
Specific Energy Consumption ◽  
Hydraulic Press ◽  
Corn Cob ◽  
Corn Cobs ◽  
Specific Energy Requirement ◽  
Ground Corn

Corn cobs are potential feedstock for producing heat, power, fuels, and chemicals. Densification of corn cobs into briquettes/pellets would improve their bulk handling, transportation, and storage properties. The objective of this study was to investigate the densification characteristics and specific energy requirements for the compression of corn cobs under four pressure levels (10, 12, 14, 16MPa) and with two particle size levels (2.41mm, 0.86mm). The compression behavior of ground corn cobs was studied using a hydraulic press briquetteing machine whose cylindrical die diameter was about 30 mm. The corn cobs moisture content and preheat temperature before compaction was 10% (w.b.) and 75 °C, respectively. The cylindrical die temperature was maintained at 90 ± 5 °C. It was found that the briquette density ranged from 809 to 1043 kg m-3; while the total specific energy requirement to compress and extrude briquette ranged from 17 to 26 MJ t-1, with an increase in pressure. Particle size had also a significant effect on briquette density and specific energy requirement. The finer corn cob grinds (0.86mm) resulted in higher density and lower specific energy requirement than the coarser corn cob grinds (2.41mm). New statistical models were developed to describe the total specific energy consumption of ground corn cobs during densification using a multiple linear regression analysis.

Energy consumption, thermal utilization efficiency and hypericin content in drying leaves of St John’s Wort (Hypericum Perforatum)

2014 ◽  
Vol 25 (3) ◽  
pp. 27-35 ◽  
Author(s):  
Saeid Minaei ◽  
Hossein Ahmadi Chenarbon ◽  
Ali Motevali ◽  
Akbar Arab Hosseini
Keyword(s):  
Energy Consumption ◽  
Specific Energy ◽  
Energy Requirement ◽  
Sample Thickness ◽  
Utilization Efficiency ◽  
Total Energy Consumption ◽  
St John’S Wort ◽  
St John's Wort ◽  
Specific Energy Requirement ◽  
Air Dryer

Massive consumption of energy in the drying industry has prompted extensive research regarding various aspects of drying energy and requirements. Thermal utilization efficiency, specific energy requirement, total energy consumption and hypericin content in drying of St John’s Wort were determined using a hot-air dryer. Experiments were conducted at four air temperature levels (40, 50, 60, and 70°C), three air velocities (0.3, 0.7, and 1 m/s) and three sample thicknesses (1, 2 and 3 cm). Based on the results of data analysis, minimum and maximum levels of energy consumption were 0.56 and 3.24 kWh, respectively. The required specific energy decreased with increasing sample thickness. The minimum and maximum required specific energies were 4.41 and 17.53 for 2 cm thick and 4.28 and 13.67 for 3 cm thick layers (kWh/kg), respectively. The maximum and minimum values of thermal utilization efficiency in different treatments were found to be 14% and 72%, respectively. Hypericin content decreased with increasing temperature and increased with air velocity and product sample thickness, so that the minimum and maximum hypericin amounts were 67 and 355 ppm, respectively.

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