摘要
蓖麻籽是一种重要的高含油(约50%)、高含蛋白(约15%)和低含水(约6%)的工业油料,采用单轴冷态压榨制油的方式能保证饼中蛋白质的低变性程度,其后续环节多辅以溶剂浸提,以提高油料的出油率。对于冷态压榨过程,其中的临界压缩比一定程度上反映了预压制油的极限能力。直筒压榨时,受到轴向压力的作用不断被压缩,使其细胞被破坏,最终油从细胞中迁移析出并不断聚集,当油的数量达到某一临界值时便从榨筒孔壁中渗出并逐渐成股连续流出,榨筒底部流出的量远多于上部,压榨完成后,榨饼成为固结体系,成为半固态饱和物料,残余应力的存在导致榨饼与榨筒壁间存在极大的摩擦力,是影响低功耗、机械化分离的关键所在。笔者应用自制带压力数据采集系统的微型直筒式压榨试验装置,研究压榨压力、压榨速度和保压时间对蓖麻籽压榨出油率的影响;在此基础上,依据产油价值等于耗能价值,分别构建了蓖麻籽单轴压榨制油临界压缩比模型;根据出油率结果,求解得到完整蓖麻籽的临界压缩比为6.2,碾碎蓖麻籽的临界压缩比为3.6。研究结果可为蓖麻压榨机的设计及压榨实践操作提供可靠的数据支撑。
Castor is an important kind of industrial oil plant with nigh oil content of about 50%, high protein content of about 15%, and low moisture content of about 6%. A cold pressing process is required to ensure a low degree of protein denaturation when pressed for castor oil. Castor cake is then extracted by solvent to reduce the residual oil of the meal. Main contents of castor beans, feeding morphology and the operating temperature can affect the pressing effect directly. Critical compression ratio of oilseeds is a key reflection for pressing ability of pre-press. In the process of cold pressing, oilseeds are squeezed and ruptured under the interaction with the barrel by the axial compression and lateral limit. Oils in the cells are gradually squeezed out only leaving the cake inside the cylinder barrel. While oilseeds were compressed by axial pressure to make the cells destroyed, drop of the oil was pressed out from the cell through micro holes and gathered to form a flow where there were much more in the bottom than in the top. After pressing, the pressed cake becomes a kind of consolidated system with semi-solid material saturation. The presence of residual stresses caused big friction between barrel and cake, which has a significant effect on low power consumption and mechanized separation lines. Using self-made testing apparatus, experimental tests on castor oil rate were carried out in different pressing pressure and velocities, and the pressure holding time. Based on the principle that oil production value was equal to energy consumption value, the relationship model between critical compression ratio and residual oil rate was established. It was calculated that the parameters of critical compression ratios for intact castor beans were 6. 2 and 3.6 for crushed seeds, which will provide a reliable data support for the design and operation of castor beans squeezer.
出处
《林业工程学报》
北大核心
2017年第2期83-88,共6页
Journal of Forestry Engineering
基金
国家自然科学基金(31470594)
长沙市科技计划(K1508130-61)
关键词
蓖麻籽
压缩比
残油率
临界压缩比
产油价值
耗能价值
castor beans
compression ratio
residual oil rate
critical compression ratio
oil production value
energy
