• Journal of environmental and Sanitary engineering
• /
• v.13 no.1
• /
• pp.9-15
• /
• 1998

Microwave heating and drying processes have been well established in various industrial applications. Feasibilities of successful application of microwave drying to many material have been shown on the laboratory or pilot-plant scale. The microwave drying behavior of plating sludge are considered in this paper. The plating sludge containing 70%, 80% and 90% water exposed to microwave power at 2,450 MHz, 700W. An experimental microwave drying apparatus was designed and constructed to monitor weight loss during drying. By studying the drying characteristic curve, the moisture in sludge was almost classified into two categories : free moisture and intestinal moisture. And the critical moisture contents at which the drying rate ceases to be constant were from 10.1 to 10.5%. A simple drying model is proposed which may be used to describe drying behavior of plating sludge. The constant rate and the falling rate periods in microwave drying were addressed separately. From the eqation of constant rate period the drying rate constants decreased exponentially with increasing depth. Microwave heating compared with conventional heating offered higher heating rates from 9 to 16 times. Therefore, microwave drying process can be effective in removing moisture from plating sludge.

• Journal of Environmental Science International
• /
• v.30 no.2
• /
• pp.135-143
• /
• 2021

This study executed evaluation of drying characteristics based on the polymer injection rate (8%, 10% and 12%) and the drying method[NIF(near-infrared ray). According to this study analyzed VS, VS/TS, and calorific value compared with 'the auxiliary fuel standard of the thermoelectric power plant and the combined heat & power plant'. The results are as follows. In the case of NIR, the VS was slightly changed at the early stage of the material preheating period and the constant drying rate period with low moisture evaporation. But VS reduction was shown higher as moisture was dried. In the case of non-digested sludge with high VS content, the VS reduction rate by drying was shown lower than that of digested sludge. As the flocculant injection rate increased, the VS loss due th drying was found to be small. Also, the higher the flocculant injection rate was the longer the drying time. Especially, in the case of the NIR drying equipment, as the moisture content of sewage sludge decreased(moisture content 20~40%), the loss of net VS also showed a tendency to increase sharply. It is shown that the high calorific value according to the drying time of the non-digested sludge was changed from 590 kcaℓ/kg to 3,005 kcaℓ/kg and from 539 kcaℓ/kg to 2,796 kcaℓ/kg.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.25 no.1
• /
• pp.23-33
• /
• 2017

In this study, water and organic treatment efficiency and operating characteristics (temperature, salinity effect) were evaluated when food waste with high water content was treated by Bio-dying method. In addition, the optimum conditions for producing pellets for evaluating the decomposition products as SRF(Solid Refuse Fuel) after Bio-drying and evaluating the use value of SRF as a solid fuel were analyzed. As a result, the temperature, $CO_2$ concentration, organic matter removal rate and weight reduction rate according to the daily dose were about 86% and 68% at the input of 2.4 kg/day. The optimal food waste input was estimated to be 2.4 kg/day. As a result of the pellet molding and produce, Pellets can be produced within 10~25% of raw material water content. It was judged that the water content of 25%, which showed the best quality results in terms of external shape maintenance and strength. The high calorific value of SRF of decomposition products after Bio-drying was more than 3,500 kcal/kg.

• Korean Journal of Food Science and Technology
• /
• v.46 no.5
• /
• pp.636-640
• /
• 2014

This study was conducted to provide basic information about the drying methods (daylight, hot-air, and freeze drying) used for Platycodon grandiflorum radix. We investigated the mineral, free sugar, and saponin contents of dried P. grandiflorum. The potassium and calcium contents of hot-air-dried samples were the highest (22.6 and 9.2 mg%, respectively), when compared to those of daylight- or freeze-dried samples. Glucose and sucrose contents were the highest in freeze-dried samples (1,552 and 145.0 mg%, respectively), while fructose content was the highest in hot-air-dried samples (611.9 mg%). Platycodin D content was the highest in hot-air-dried samples (622.0 mg%); however platycodin D3, polygalacin D, and deapioplatycodin D contents were the highest in daylight-dried plant (113.5, 756.6, and 109.2 mg%, respectively). Glucose content was highly negatively correlated (p<0.01) with platycodin D, platycodin D3, and deapioplatycodin D (-0.924, -0.957, -0.861, p<0.01, respectively). These results suggest that the drying method affects the saponin content of P. grandiflorum and daylight and hot-air drying methods are more suitable and beneficial than freeze-drying.

• Archives of Pharmacal Research
• /
• v.29 no.10
• /
• pp.921-927
• /
• 2006

Prolonged release micro particles of clarithromycin (CL) were prepared using Eudragit RL 100 and RS 100 by spray-drying and casting-drying techniques. For the characterization of those microparticles, preparation yield, particle size distribution, X-ray diffraction, thermal behavior, active agent content and in vitro dissolution from the microparticles were performed. HPLC was used for the assay of clarithromycin and the assay method was validated. All the formulations obtained showed prolonged release when compared to pure clarithromycin. Microparticles prepared by spray-drying method had a slower release compared to those of casting drying method. Spray-drying method seems to be a more suitable method to prepare microparticles for prolongation in release.

• Korean Journal of Plant Resources
• /
• v.26 no.3
• /
• pp.389-396
• /
• 2013

The antioxidant enzyme and DPPH radical scavenging activity with variations in drying methods of diploid and tetraploid in Platycodon grandiflorum were determined. Antioxidant enzyme activities were measured as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX). The roots of Platycodon grandiflorum were freeze-dried, indoor-dried, hot-air dried, and microwave dried. The root extract of P. grandiflorum have shown the highest SOD enzyme activity of 92% in tetraploid of freeze-dried and indoor-dried while diploid of microwave dried showed the lowest SOD enzyme activity of 47.5%. The activity of CAT showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all drying methods. The APX activity showed relatively higher values in the root extract of freeze-dried both the diploid and tetraploid, but the difference in comparison with other extracts was not significant. The POX activities according to drying methods of diploid and tetraploid in P. grandiflorum showed relatively high values in freeze-dried and indoor-dried compared with other drying methods, and the POX activity between the diploid and tetraploid was not significant difference in each drying method. The DPPH radical scavenging activity with variation in drying methods of diploid and tetraploid in P. grandiflorum was the highest in the freeze-dried, and was higher in tetraploid than diploid in all the concentrations. In conclusion, the root of P. grandiflorum had the potent biological activities in both diploid and tetraploid. In particular, the tetraploid root of P. grandiflorum showing high antioxidant enzyme activity could be good materials for development of source of functional healthy food.

• Journal of Korea Society of Waste Management
• /
• v.35 no.7
• /
• pp.600-605
• /
• 2018

In this study, the combustion characteristics were investigated based on the biodrying solid recovered fuel (SRF) in a 5 Ton/day scale combustion boiler. The composition of the combustion gas containing the biodrying SRF was analyzed, the particulate matter, and its HCl content was determined with the air pollutant process test method. Mass balance, carbon balance, and combustion efficiency were calculated according to the equivalence ratio (ER) method; the energy recovery efficiency of the combustion boiler was also analyzed. The overall combustion efficiency of the biodrying SRF was 97.3 % and the energy recovery efficiency was 80.2%.

• Journal of agriculture & life science
• /
• v.53 no.5
• /
• pp.137-143
• /
• 2019

To manufacturing of solid fuel by reuse of the wastes, the drying unit which have 500 kg/hr of drying capacity was developed and experimentally evaluate the performance. The spinach grown in Nam-hae island were used for the experiments and investigated of the heated-air drying characteristics as the inlet amount of raw materials, raw material stirring status, conveying type and drying time. The drying air heated by the energy derived from the steam which is supplied from the incineration plant. The moisture contents of raw materials were measured 85.65%. The inlet flow rate of drying air made a difference as the depth of the raw materials loaded on the drying unit and temperature has showed 108~144℃. The drying speed of the mixed drying more than doubled as that of non mixed drying under the same drying type, inlet amount, drying time and drying air temperature. In each experiment, the drying capacity have showed over 500 kg/hr. A drying efficiency of the ratio of drying consumption energy to input energy was 33.46%, lower than the average of 57.76% for the 157 conventional dryers. Because developed dryer must have a drying time of less than one hour, it is considered that the dry efficiency has been reduced due to the loss of wind volume during drying. If waste heat from incineration plant is used as a direct heat source, the dry air temperature is expected to be at least 160℃, greatly improving the drying capacity.

• Applied Chemistry for Engineering
• /
• v.31 no.2
• /
• pp.208-214
• /
• 2020

In this study, the characteristics and mechanism of microwave-assisted drying were investigated to improve the efficiency of the storage and extraction of biomass through the removal of moisture from plant cell Taxus chinensis. The efficiency of microwave-assisted drying increased with increasing microwave power. When the experimental data were fitted to typical drying kinetic models, the page and modified Page models were the most appropriate. The microwave-assisted drying was determined to be a spontaneous endothermic process, and randomness increased during the drying process. The effective diffusion coefficient (3.445 × 10^-9~7.163 × 10^-7 ㎡/s) and mass transfer coefficient (3.1529 × 10^-5~1.2895 × 10^-2 m/s) increased with increasing microwave power. The small Biot number (0.3890~0.7198) indicated that the mass transfer process was externally controlled.

• Korean Journal of Plant Resources
• /
• v.17 no.3
• /
• pp.219-226
• /
• 2004

Transplantings of onion (Allium cepa L.) seedlings are required for higher germinability and uniformity. This study was done to determine effects of various seed treatments (seed cleaning, priming, GA$_3$, prechilling, drying, and light quality during seed drying) on germination and seedling emergence. Nongwoodaego and Changnyungdaego were used as cultivars for checking seed germination, and two cultivars and Cheonjuguhyeonghwang were investigated with seedling production rate. Seed cleaning using water prior to the other treatments greatly increased germination rate. Priming with 200mM Ca(NO$_3$)$_2$ solution somewhat alleviated the germination rate while GA$_3$ did not. Prechilling had the highest rate among the treatments. Seed drying after prechilling enhanced the rate compared to non drying, and during drying the prechilled seeds red light illumination showed the greatest rate in comparison with dark, blue, and far-red ones. Seedling production rate was enhanced in sequential treatments of seed cleaning, prechilling for 3 to 5 days, and red light treatment during 6 hour seed drying.