濃硫酸による木材糖化プロセスに関する研究 : (第14報)透気乾燥糖化プロセスの研究(その2) : 「木材チップの乾燥糖化」

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In order to study the through flow drying operation in connection with the selection of the best type of drying equipment for wood saccharification, white birch chips were chosen. After having them sufficiently impregnated with a solution of calcium chloride and sulfuric acid solution of a medium strength, the correlation between the conditions of the drying operation and the drying rate, and the correlation between the operating conditions and the reaction therein were observed to discover the most effecient operating conditions.The pre-hydrolysis rate and the main-hydrolysis rate in this wood saccharification process were controlled by the length of the chips in the direction of the fibers and it was assumed that 3-4mm were most suitable.In the early stage of the drying of pre-hydrolyzed chips, there was a short period where they were kept at a constant drying rate equivalent to the constant drying rate of ordinary drying.In the case of the chips impregnated with sulfuric acid solution, the heat transfer capacity coefficient ha (Kcal/m^3hr. ℃) was expressed as a function of air flow velocity (cm/sec) by the following formula : ha=4.73Va^<1.18>In this reaction, drying was different from other drying conditions in that air humidity was required to be lower than 2.0×10^<-3> H_2O/kg of dry air in the later period of drying for satisfactory control of the reaction.It became apparent that the simultaneous regulation of temperature and hydrolysis rate of the chips was very important for preventing the decomposition of the reducing sugar produced.Temperature ranges of 50-70℃ in the early stage and 40-55℃ for the later stage were necessary as satisfactory operating conditions.Unequal reaction mainly due to the local uneven temperatures in the chips bed could be prevented by turning the reaction bed.In this respect, air velocity also had some influence and an air current higher than 60 cm/sec necessary for preventing uneven reaction.The pressure drop, air passing through the layer of chips, was much varied by the size of chips, pre-hydrolysis method, and the method of filling chips, but it was discovered that little variation in the air pressure drop took place during the drying process.Observed pressure drop through the bed of pre-hydrolyzed white birch chips baving a size 4×1.5×10〜15mm is expressed by the following equation : ΔP/L=6〜11×10^<-4> Va^<1.73〜1.75> Where ΔP represents pressure drop in the bed of chips in mm Aq L depth of prehydrolysed chips in cm.Va air velocity varying with the cross-sectional area of the bed in cm/sec From this study of the main-hydrolysis process, it may be concluded that : (1) The process of employing the through-flow drying operation should be divided into two parts from the standpoint of operation control;(2) The first part of the drying operation can be performed at a relatively high temperature, high humidity and high air velocity for a short period;(3) The second of the drying operation must be performed under the control of air flow by maintaining the temperature, humidity, and velocity low in a state of low level for obtaining a satisfactory reducing sugar yield.
社団法人日本生物工学会の論文
1962-08-15

濃硫酸による木材糖化プロセスに関する研究 : (第14報)透気乾燥糖化プロセスの研究(その2) : 「木材チップの乾燥糖化」

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