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No.30 (1983/11) >

 
Title :沖縄の製糖工場における各中間産物の粘性挙動(農業工学科)
Title alternative :Viscositic Behavior of Products in Several Steps in Sugar Cane Mills in Okinawa (Department of Agricultural Engineering)
Authors :國府田, 佳弘
川崎, 聖司
Authors alternative :Kohda, Yoshihiro
Kawasaki, Seiji
Issue Date :19-Nov-1983
Abstract :沖縄の製糖工場から得られた各工程中の産生物である清浄汁, 濃縮汁, 白下, 糖蜜を用いて定常流粘性を測定し, それらの流動特性を解析した。またこれらの知見をもとにハワイ製糖工場における測定結果と比較を行った。糖蜜は粘度が約20ポイズ以上になると顕著に非ニュートン流動を示すようになった。各ずり速度と温度は両対数グラフ上で直線近似ができ, アレニウス型の粘性挙動をとることが示された。これら直線の勾配及び切片は各製糖工場に特徴的であり, 製造工程中の操作条件や装置の相異がこれら産生物の流動特性に大きな影響を及ぼしていることが明らかとなった。清浄汁及び濃縮汁は50℃において粘度が各々0.01及び0.1ポイズであり, ともにニュートン流動を示した。三番白下は一番と比較すると粘度が10倍程度高くなっているが, これは晶出操作に伴う高分子画分の増加や, あるいは蔗糖の結晶が粘性の増加に起因しているものと思われる。本実験によって得られた糖蜜の粘性挙動はハワイ産糖蜜の結果とよく一致した。
The viscosity of suger cane juice were measured as a function of shear rate, temperature and process variables. Sample solutions of clear juice, syrup, molasses and massecuite were kindly supplied by five sugar manufacturing factories in Okinawa. The measurements of viscosity were carried out with a co-axial viscometer at various temperatures and shear rate. The flow properties of these solutions were also compared with that of Hawaiian factories. The results obtained were as follows : When viscosity exceeded about 20 poise or more, rheological behavior of molassess exhibited non-Newtonian flow. Temperature dependence of viscosity for molasses was different from each other among five factories. Logarithm of viscosity (log η) versus logarithm of temperature (log t) curves of five kinds of molasses were proximated by the straight line, which indicated that temperature dependence of viscosity could be expressed by the Arrhenius type equation. In general, the slope (-d log η/d log t) of the molasses which was produced by the diffusion method had larger values than the molasses by roll mill method. These results indicated that the difference of process variables including extraction method of cane juice, concentration of clear juice and crystallization of sugar so on reflected the flow properties of the molasses. Viscosity of clear juice were almost independent to shear rate and their absolute values were about 0.01 poise at 50℃. Syrup also showed Newtonian flow and viscosity was about 0.1 poise at 50℃. Viscosity of the third massecuite was 10 times as large as the first massecuite, and their flow propeties exhibited non-Newtonian behavior more significantly with increasing crystallization times. These results seems to reflect that the increase in high molecular weight substance or impurities in addition to the sugar crystal in the massecuite would enchance the molecular interaction of massecuite solution giving non-Newtonian flow. Viscosity values of suger cane juice in this study were coincide very well with that of Hawaiian factories within a reasonable defference.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4004
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.30 p.489 -497
Appears in Collections:No.30 (1983/11)

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