Performance evaluation of a flatbed maize dryer with a biomass heat source

The technical performance of a 3-tonne capacity flatbed grain dryer was assessed based on its drying rate and drying efficiency. In addition, the quality of maize grains dried in the drying system was investigated through stress-crack analysis and germination test. Maize grains at an initial moisture content of 18.4% ± 0.1% (wb) were dried to a safe moisture content of 13.3% ± 0.2% (wb) in 5 hours, resulting in a drying rate of 1.02%/h at a drying efficiency of 67.35%. The average temperature observed in the plenum (55.8°C±1.5°C) was about twice higher than the ambient temperature during the drying period. The use of the flatbed dryer did not have any adverse effect on the viability of grains dried with a stress-crack index of 75 and percentage germination of 90%. This study demonstrated the viability of using the flatbed biomass-assisted dryer for drying maize and can reduce post-harvest losses of maize at the smallholder level. Int. J. Agril. Res. Innov. Tech. 11(2): 37-41, Dec 2021

Structure Optimization of Outlet Uniformity for a Comas Tower Dryer

Tobacco drying is an important part in the whole process of cigarette production, and its quality is directly related to the quality of cigarettes. CTD (Comas Tower Dryer) is a new type of airflow dryer, which is widely used in the tobacco industry because of its high drying efficiency. In actual production, the uneven outlet of the tobacco cutter leads to a stacking phenomenon, which affects the subsequent process of production. In this paper, the distribution of the internal flow field of the drying tower was studied from the aspects of the overlap degree of the orifice plate and deformation of the top structure at the top of the drying tower to explore the way to optimize the inner flow field to lead to the uneven distribution of the outlet. The results show that the structure whose contact position between the wall and the outlet extending outward can improve the uniformity of the outlet, while the overlap degree of the orifice plate had no effect on the uniformity of the outlet.

Energy Performance Analysis of Convective Drying of Sorghum Gruel Residue

This research is concerned with the energy performance analysis of convective drying of sorghum gruel residue. The process was carried out on a hot air dryer conducted at four drying air temperatures of 40, 50, 60, and 70 °C respectively, three different air velocities 0.8, 1.0 and 1.2m/s and three different varieties of sorghum gruel residue, Caudatum,Durra and Guineense respectively. The effects of drying temperature and air velocities on the specific energy consumption, energy efficiency, drying efficiency and thermal efficiency were investigated. The specific energy consumption for Caudatum,Durra, Guineensevarieties ranges from 169530.001 J/kg - 71433.758 J/kg, 170557.25 J/kg - 76732.96 J/kg and 179367.266 J/kg - 83750.923 J/kg respectively while the energy efficiency for Caudatum,Durra, Guineensevarieties ranges from 35.5% - 13.934%, 31.188% - 13.836% and 28.463% - 13.157% respectively. The results of this study also confirmed that the convective drying process is energy intensive and drying fresh agricultural produce with heated-air dryers requires a relatively large amount of energy.

Effect of Spray Dryer Scale Size on the Properties of Dried Beetroot Juice

Experiments detailing the spray drying of fruit and vegetable juices are necessary at the experimental scale in order to determine the optimum drying conditions and to select the most appropriate carriers and solution formulations for drying on the industrial scale. In this study, the spray-drying process of beetroot juice concentrate on a maltodextrin carrier was analyzed at different dryer scales: mini-laboratory (ML), semi-technical (ST), small industrial (SI), and large industrial (LI). Selected physicochemical properties of the beetroot powders that were obtained (size and microstructure of the powder particles, loose and tapped bulk density, powder flowability, moisture, water activity, violet betalain, and polyphenol content) and their drying efficiencies were determined. Spray drying with the same process parameters but at a larger scale makes it possible to obtain beetroot powders with a larger particle size, better flowability, a color that is more shifted towards red and blue, and a higher retention of violet betalain pigments and polyphenols. As the size of the spray dryer increases, the efficiency of the process expressed in powder yield also increases. To obtain a drying efficiency >90% on an industrial scale, process conditions should be selected to obtain an efficiency of a min. of 50% at the laboratory scale or 80% at the semi-technical scale. Designing the industrial process for spray dryers with a centrifugal atomization system is definitely more effective at the semi-technical scale with the same atomization system than it is at laboratory scale with a two-fluid nozzle.

Analysis of heat energy in the drying process of Moringa Oleifera leaves using a greenhouse effect dryer (ERK)

Moringa leaves have a high enough nutrient content so that they are used as a source of natural nutrients. Fresh moringa leaves have a high water content, so they need to be dried to reduce post-harvest loss. This study aims to analyze heat energy in the drying process of moringa leaves using a greenhouse effect type dryer (ERK). The study was an experimental method on drying of moringa leaves using a Greenhouse Effect (ERK) in the field and was analyzed using mass and energy equilibrium approaches. In this study, two different treatments were carried out i.e not crushed and crushed leaves. The result shows that the water content of the uncrushed and crushed leaves were 74.9%wb and 71.4%wb, dried moringa leaf water content was 4.8 %wb and 4.5%wb. Total energy entered by dryers 7415038.8 kJ and 7780575.4 kJ, Total useful energy of 767089.470 kJ and 2171369.143 kJ, total energy discharged through outlet/ventilation and lost through successive walls were is 4148.222 kJ, 5718.912 kJ, 8.924 kJ and 7.194 kJ as well as heat lost from opening consecutive doors of 771246.62 kJ and 2177095.25 kJ. The input masses were 0.75 kg and 1.35 kg, the output mass were 0.180 kg and 0.391 kg, the accumulated mass were 0.570 kg and 0.959 kg. Drying efficiency values were 18.25% and 29.26%.

EFFECT OF DRYING KINETICS ON THE QUALITY OF THE GREEN CAPSICUM

The effect of power (Watt) of microwave assistance drying on consumption of energy, drying efficiency and kinetic studies in green capsicum (Capsicum annum) was studied. For describing green capsicum drying behavior two mathematical models (Lewis model and Parabolic model) are used. Based on their root mean square error, χ2 and R2, values of predicted and experimental moisture content to models are compared. The drying time of green capsicum was decreased from 47 minutes to 22 minutes due to increasing power of microwave from 180 Watt to 900 Watt. The drying process was showing a falling rate period. In Lewis model the result shown most appropriate model for the study. For co-relation of moisture content with effective moisture diffusivity a third-order relationship was found. The effective moisture diffusivity of Green Capsicum samples increased as the moisture content decreased. Over the microwave power spectrum tested, the effective diffusivity ranged from 1.5 X 1012 m2/sec to 4.3 X 108 m2/sec, with an energy activation of 31.74 W/g. As microwave power and moisture content increased, so did energy efficiency.

Analysis of the Sand Drying Process in the Biomass-Energized Rotary Drying Machine

Hebel brick (also known as a lightweight brick) is a product of modern building materials because it has a lighter weight but it is stronger than cement bricks and red bricks. Hebel bricks can withstand pressures of more than 4 MPa and are suitable as building wall materials, and speed up construction, and save on cement material costs. One of the most important materials is silica sand in the manufacture of Hebel bricks. The silica sand used in the manufacture of Hebel bricks must have a moisture content of 10 % to 15 %. The purpose of this study is to provide a solution in the form of a drying technique design using a rotational speed control method and a machine that uses biomass-based energy sources. This rotary drying machine is designed to be able to dry wet silica sand into silica sand with water content according to standards. The development of this drying machine begins with making an initial design and parameter analysis. Then proceed to the design, manufacture, and performance testing. The calculation results show that the wet base moisture content has decreased from 33.17 % to 16.58 %, the dry base moisture content decreased from 49.63 % to 19.88 % and drying efficiency also decreased from 63.11 % to 17.11 %. Hence it can be seen that the percentage of wet base moisture content reduced by 50 %, the percentage of dry base moisture content reduced by 59.94 %, and the percentage of drying efficiency reduced by 72.9 %.

Thermally Induced Silane Dehydrocoupling: Hydrophobic and Oleophilic Filter Paper Preparation for Water Separation and Removal from Organic Solvents

Organic solvents with high purity are essential in various fields such as optical, electronic, pharmaceutical, and chemical areas to prevent low-quality products or undesired side-products. Constructing methods to remove impurities such as water residue in organic solvents has been a significant challenge. Within this article, we report for the first time a new method for the preparation of hydrophobic and oleophilic filter paper (named OCFP), based on thermally induced silane dehydrocoupling between cellulose-based filter paper and octadecylsilane. We comprehensively characterized OCFP using various characterization techniques (FTIR, XPS, XRD, and EDS). OCFP showed super-hydrophobic and oleophilic properties as well as remarkable water separation and removal efficiency (>93%) in various organic solvents with sustained reusability. In addition, the analytical results both before and after filtration of an NMR solvent using OCFP indicated that OCFP has an excellent solvent drying efficiency. This work presents a new strategy for the development of super-hydrophobic cellulose-based filter paper, which has great potential for solvent drying and water separation.

Experimentation and performance analysis of solar-assisted heat pump dryer for intermittent drying of food chips

A solar-assisted heat pump dryer is fabricated for intermittent drying. The experiment is performed for different intermittency ratios for radish drying using future refrigerant R1234yf. The effects of total drying time (on-period + off-period) on various energetic, exergetic, and economic performances are investigated. Radish chips were dried to extract moisture from 92.4% to 11.9%. Energy efficiency and drying efficiency are estimated higher for a lower intermittency ratio. The moisture extraction rate and specific moisture extraction rate are higher for intermittent drying as compared to continuous drying and increase with a decrease in intermittency ratio. The economic analysis concludes that the payback period is lower for a lower intermittency ratio. The payback period for intermittency ratio of 1, 0.66, 0.33 and 0.2 are estimated as 1.617 years, 1.459 years, 1.384 years, and 1.347 years, respectively. Present experimental thermo-economic analysis reveals that intermittent drying is much better (maximum enhancement of specific moisture extraction rate is 60.6%, that of energy efficiency is 56.4% and maximum reduction of drying cost is 37.9% with studied conditions) than continuous drying.