• Title, Summary, Keyword: rice husk

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Production of Carbonized Rice Husk by a Cyclone Combustor(II) (사이클론 연소기를 이용한 탄화왕겨의 제조(II))

  • 김원태;노수영
    • Journal of Biosystems Engineering
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    • v.24 no.6
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    • pp.487-492
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    • 1999
  • One of effective utilization method of rice husk is to utilize it as culture material by carbonizing the rice husk. As a second part of a series to investigate the effective and continuous production of carbonized rice husk by a cyclone combustor, a non-slagging vertical cyclone combustor without vortex collector pocket was introduced. Isothermal and mixed firing with LPG and rice husk were undertaken in order to characterize the system. Inert rice husk was used during the isothermal test to find mass of rice husk collected. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. Cyclone combustor was operated at temperatures of 1,273~1,473K. Detailed combustion data were obtained from a pilot unit with the air flow rate of 70m$^3$/h and rice husk feed of 2kg. The equivalence ratio ranged from 0.66 to 3.48. The auxiliary gas flow rate was varied from 3.22 to 12.86$\ell$/min. The weight reduction, pH and particle size distribution of carbonized rice husk were measured to evaluate the quality of carbonized rice husk. An analysis of exhaust gas emission was conducted to characterize the combustor. The required carbonized rice husk could be obtained at equivalence ratio of 1.68~2.17, combustor temperature of 1,273~1,373K and auxiliary gas flow rate of 3.22~6.43$\ell$/min. A method to reduce CO emissions should be employed.

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Study of Rice Husk Pulping for utilization of Rice Husk Fiber (왕겨섬유 활용을 위한 왕겨 펄프화 연구)

  • Oh, Min-Taek;Sun, Yong-Joo
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.3
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    • pp.63-69
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    • 2012
  • The rice husk is one of the major agricultural residue in KOREA. In this paper, the effects of various pulping conditions on the properties of rice husk pulp and handsheets made of rice husk fiber were evaluated in order to utilize the rice husk as an alternative source for wood pulp. Two typical alkali pulping, such as soda pulping and Kraft pulping were applied with various conditions of the pulping processes. The higher effective alkali and higher pulping temperature resulted in the higher efficiency in removal of lignin and ash, which leaded to the higher strength properties of handsheets made of rice husk fiber, but the lower yield of rice husk pulp. The better efficiency in production of rice husk pulp and the stronger handsheets were obtained by the Kraft pulping.

Production of Carbonized Rice Husks by a Cyclone Combustor(I) (사이클론 연소기를 이용한 탄화왕겨의 제조(I))

  • 고길표;노수영
    • Journal of Biosystems Engineering
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    • v.23 no.1
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    • pp.13-20
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    • 1998
  • Carbonized rice husk(char from rice husk) can be used to improve soils for planting, seedlings, horiculture, pomiculture and truck gardening. Although it is not a fertilizer in nature, it stimulates the growth of plants. Carbonized rice husk is highly recommended for raising soil/water temperature, keeping moisture and aerating roots of plants. The objective of this study was to develop the effective production method of carbonized rice husks by a non-slagging vertical cyclone combustor. A cyclone combustor w vortex collecor Pocket in addition to central collector pocket was selected and tested. Isothermal tests and mixed firing with LPG and rice husk were performed in order to characterize the system. hut rice husk was used during the isothermal test to find the mass collected of rice husk. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. The composition of original and carbonized rice husks was analyzed by the ultimate analysis. With the air flow rate of 20 ㎥/h, LPG flow rate of 0.45 1/min, the required carbonized rice husk could be obtained.

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Hydration, Strength and pH Properties of Porous Concrete Using Rice Husk Ash

  • Kim, Young-Ik;Sung, Chan-Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.3
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    • pp.51-60
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    • 2007
  • This study was performed to evaluate void ratio, compressive and flexural strengths, and pH properties according to the content ratio of rice husk ash, aggregate size, and neutral treatment time of porous concrete with content of rice husk ash produced as an agricultural by-product. The SEM results for cement mortar with a 5% rice husk ash for the weight of cement formed more C-S-H hydrates due to the $SiO_2$ of rice husk ash. In the XRD test, cement mortar with a 5% rice husk ash for the weight of cement registered a higher peak point of approximately $2{\theta}=20{\sim}25^{\circ}$ compared to cement mortar without rice husk ash. According to the results of the XRD and SEM tests, the $SiO_2$ that was a major chemical element of rice husk ash generated a large amount of calcium hydroxide in the early stage of the hydration process of cement leading to the formation of ettringite. The void ratio of porous concrete with rice husk ash decreased with increasing content ratio of rice husk ash. In addition, the void ratio of porous concrete with rice husk ash decreased compared to porous concrete without rice husk ash. The compressive and flexural strength of porous concrete with a 5% and 10% content ratio of rice husk ash slightly increased compared to concrete without rice husk ash. The pH value of porous concrete rapidly decreased immediately after neutral treatment. Then, it gradually increased and decreased again after 14 days. However, the pH value was nearly the same regardless of neutral treatment time in 28 curing days. Also, for neutral treatment, the pH value of porous concrete showed appropriate pH levels (less than 9.5) in all mixtures for planting at 28 curing days.

Chemical Compositions and Thermal Characteristics of Rice Husk and Rice Husk Ash in Korea (왕겨 및 왕겨재의 화학적 조성 성분과 열적 특성)

  • Park S. J.;Kim M. H.;Shin H. M.
    • Journal of Biosystems Engineering
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    • v.30 no.4
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    • pp.235-241
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    • 2005
  • For better and large utilization of rice husk, the production and consumption status, differences in chemical composition and heating value due to region and variety, and thermogravimetric characteristic of rice husk were studied. In addition, the differences in chemical composition due to region and variety and the crystallization characteristic of rice husk ash were also studied. Approximately 800,000 M/T of rice husk was produced per year in Korea, which is about $18\%$ of the paddy production by weight. Noticeable varietal and regional difference pattern in chemical composition was not found among the domestic rice husk samples. Their average ash content and higher heating value were $16.4\%$ and 16,660 kJ/kg by dry basis, respectively. A relation seemed to exist between the carbon content and higher heating value. Noticeable difference pattern in chemical composition was not found among the domestic rice husk ash samples. The $SiO_2$ contents were a little low, the maximum being $92.9\%,$ and the contents of major components such as CaO, MgO, and $K_2O$ were also lower compared with foreign rice husk ash due to the deficiency of compost matters in domestic soils. Thermogravimetry study showed the thermal decomposition of rice husk started at about $250^{\circ}C,$ followed by relatively fast combustion of combustible gas until the temperature rose to $350^{\circ}C.$ After $350^{\circ}C,$ combustion of the carbon component proceeded relatively slowly as the temperature increased. Therefore, the ignition temperature of the rice husk could be estimated around $300^{\circ}C$. Crystallization of $SiO_2$ in the rice husk ash was found from the combustion temperature of $750^{\circ}C$ and became distinctly when the combustion temperature exceeded $900^{\circ}C$. The ash became darker with $SiO_2$ crystallization.

Void ratio and Strength Properties of Porous Concrete Utilizing Rice Husk Ash and Recycled Aggregate for Planting (식생 적용을 위한 왕겨재와 순환골재를 활용한 포러스 콘크리트의 공극률 및 강도 특성)

  • Kim, Young-Ik;Sung, Chan-Yong
    • Korean Journal of Agricultural Science
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    • v.33 no.2
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    • pp.167-177
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    • 2006
  • This study was performed to evaluate void ratio, compressive and flexural strength, and pH properties according to the admixture ratio of rice husk ash, aggregate size, and neutral treatment time of porous concrete with an admixture of rice husk ash produced as an agricultural by-product. The SEM results for cement mortar with a 5% rice husk ash admixture for the weight of cement formed more C-S-H hydrates due to the $SiO_2$ present in the applied rice husk ash. According to the results of the SEM test, the $SiO_2$ that was a major chemical element of rice husk ash generated a large amount of calcium hydroxide in the early stage of the hydration process of cement leading to the formation of ettringite. The void ratio of porous concrete with an admixture of rice husk ash decreased with increasing admixture ratio of rice husk ash. In addition, the void ratio of porous concrete with an admixture of rice husk ash decreased compared to porous concrete with no admixture of rice husk ash. The compressive and flexural strength of porous concrete with a 5% and 10% admixture ratio of rice husk ash slightly increased compared to concrete with no admixture of rice husk ash. The pH value of porous concrete rapidly decreased immediately after neutral treatment. Then, it gradually increased and decreased again after 14 days. Also, for neutral treatment, the pH value of porous concrete showed appropriate pH levels(less than 9.5) in all mixtures for planting at 28 curing days.

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Thermogravimetric Analysis of Rice Husk Flour for a New Raw Material of Lignocellulosic Fiber-Thermoplastic Polymer Composites

  • Kim, Hyun-Joong;Eom, Young-Guen
    • Journal of the Korean Wood Science and Technology
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    • v.29 no.3
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    • pp.59-67
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    • 2001
  • Rice husk flours were analyzed by chemical composition and thermogravimetric methods in nitrogen atmosphere to discuss its feasibility as a raw material for manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite. It was revealed in the chemical composition analysis that rice husk flour was composed of moisture, 5.0%; lignin, 21.6%; holocellulose, 60.8%; ash, 12.6%. In the thermogravimetric analysis (TGA), thermal decomposition behavior of rice husk flour from room temperature to $350^{\circ}C$ was similar to that of wood flour, but rice husk flour was more thermally stable from 350 to $800^{\circ}C$ than wood flour because of higher silica content in the rice husk flour and smaller particle size of rice husk flour. The activation energy of thermal decomposition was evaluated using Flynn & Wall expression. As the thermal decomposition proceeded in rice husk flour, the activation energy of thermal decomposition appeared almost constant up to ${\alpha}=0.25$, but thereafter increased. Activation energy of thermal decomposition in wood flour, however, decreased steeply up to ${\alpha}=0.3$, but thereafter remained almost constant. From the results, rice husk flour was thought be a substitute for wood flour in manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite in the aspect of thermal decomposition.

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Strength Improvement of Lime-treated Soil with Fly Ash and Rice Husk Ash (Lime - Fly Ash / Rice Husk Ash에 의한 해성퇴적토의 강도특성 개선)

  • 민덕기;황광모;이경준;김현도
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.55-62
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    • 2000
  • In this paper, a laboratory investigation was carried out to estimate the strength improvement of quicklime mixture with fly ash and rice husk ash for the effective use of surplus soils, and the shear strength with curing time was estimated at lime 10 percent with the change of fly ash and rice husk ash content. The effect of strength improvement has been established through the change of fly ash and rice husk ash content from the samples taken at Samsan region, Ulsan. The test results indicated that the presence of lime with fly ash and rice husk ash encouraged the stabilization efficiency of lime with fly ash and rice husk ash, and increased shear strength. Furthermore, it is necessary for inquiring into the relationship between the characteristics of strength and the chemical components.

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Developmemt of Rice Husk Pellets as Bio-filter Media of Bio Scrubber Odor Removal System (왕겨펠렛 생물담체 개발 및 이를 이용한 bio scrubber형 악취제거 시스템 성능평가)

  • Bae, Jiyeol;Han, Sangjong;Park, Ki Ho;Kim, Kwang-Soo
    • Journal of Korean Society for Atmospheric Environment
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    • v.34 no.4
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    • pp.554-566
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    • 2018
  • The rice husk contains nutrients which can be easily utilized by microorganisms, and also has a water retaining ability, which played a crucial part in enabling it to become a biofilter media. In this study, we evaluated the applicability of rice husk pellet bio-scrubber as a microbiological carrier. The pelletization experiment of rice husk as a biological media was performed using PVA and EVA binder. Also, the feasibility tests of rice husk as a biological media for odor removal were carried out in order to know whether rice-husk contains useful components as a media for microbiological growth or not. Lastly, a combined test for odor gas absorption and biological oxidation was conducted using a lab scale bio-filter set-up packed with rice-husk pellets as wet-scrubber. The major components of the rice husk were carbon, hydrogen, nitrogen, and oxygen, while carbon acted as the main ingredient which comprised up to 23.00%. The C : N : P ratio was calculated as 45 : 1 : 2. Oxygen uptake rate, yield and decay rate of the rice husk eluent was calculated to be $0.0049mgO_2/L/sec$, 0.24 mgSS/mgCOD and 0.004 respectively. The most stable form of rice husk pellets was produced when the weight of the rice husk, EVAc, PVAc, and distilled water was 10 : 2 : 0.2 : 10. The prepared rice husk pellets had an apparent density of 368 g/L and a porosity of 59.00% upon filling. Dry rice husks showed high adsorption capacity for ammonia gas but low adsorption capacity for hydrogen sulfide. The bio-filter odor removal column filled with rice husk pellets showed more than 99.50% removal efficiency for NH3 and H2S gas. Through the analysis of circulation water, the prime removal mechanism is assumed to be the dissolution by water, microbial nitrification, and sulfation. Finally, it was confirmed that the microorganisms could survive well on the rice husk pellets, which provided them a stable supply of nutrients for their activity in this long-term experiment. This adequate supply of nutrients from the rice husk enabled high removal efficiency by the microorganisms.

Properties of Sawdust-Rice Husk Mixed Ceramic According to The Rice Husk Mixing Ratios (왕겨의 혼합비율에 따른 톱밥⋅왕겨 혼합세라믹의 성질)

  • Oh, Seung Won
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.4
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    • pp.420-427
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    • 2014
  • The physical and mechanical properties of sawdust-rice husk mixed ceramic were investigated with rice husk mixing ratios. The mixed ceramic board was produced with carbonization and resin impregnated sawdust-rice husk board at high temperature. At the same percentage of resin impregnation condition, density and bending strength of the mixed ceramic board increased with increasing the mixing rates of rice husk, whereas weight loss of the ceramic boards decreased. At the same temperature condition for the carbonization of resin impregnated sawdust-rice husk board, the density and bending strength were the highest with 40% of rice husk mixing ratio.