造纸法烟草薄片与天然烟叶吸湿-解湿行为差异性研究

Study on the Differences in Moisture Absorption-Desorption Behaviors Between Reconstituted Tobacco Sheets Prepared by Natural Tobacco Leaves via Papermaking Method

关键词:  烟草薄片  天然烟叶  等温吸湿  解湿动力学  环境温湿度

Key Words:reconstituted tobacco sheet  natural tobacco leaf  isothermal moisture absorption  moisture desorption kinetics  environmental temperature and humidity

摘要:采用多种模型对天然烟叶与烟草薄片在制丝生产线环境下的等温吸湿-解湿行为进行拟合，借助最优等温吸湿模型与解湿动力学模型，对其等温吸湿-解湿行为进行分析。结果表明，DLP模型对天然烟叶与烟草薄片的等温吸湿行为拟合效果最好，二者的等温吸湿线分别为Ⅲ型和Ⅱ型，等温吸湿行为有较大差异；烟草薄片的吸湿滞后现象不明显，而天然烟叶在相对湿度较低时，吸湿滞后现象明显。Page模型对天然烟叶与烟草薄片的解湿过程拟合效果最好；在干燥前期，温度升高加快了烟叶的解湿速率，而在干燥后期，温度升高使得解湿速率降低；相同环境下，烟草薄片的失水速率高于天然烟叶。经验证，Page模型对烟草薄片与天然烟叶含水率的理论值和实测值相对误差均在5%内，能够较好地预测其在实际生产环境下的解湿情况。

Abstract:Various models were used to fit the isothermal moisture absorption-desorption behaviors of natural tobacco leaves and reconstituted tobacco sheets under the conditions of cut tobacco processing production line with the help of the optimum isothermal moisture absorption model and desorption kinetics model. The findings showed that the DLP model exhibited the best fitting performance for the isothermal moisture absorption behaviors of natural tobacco leaves and reconstituted tobacco sheets， and the isothermal hygroscopic curves were of type Ⅲ and type Ⅱ respectively， indicating significant differences. The moisture absorption hysteresis in reconstituted tobacco sheets was not apparent， when the relative humidity in natural tobacco leaves was low， moisture absorption hysteresis was evident. Page model provided the best fitting for the desiccation process of natural tobacco leaves and reconstituted tobacco sheets. In the early drying stages， higher temperatures accelerated the moisture desorption rate of tobacco leaves. While in the late drying stages， increasing temperature led to a slower moisture desorption rate. Under the identical conditions， the water loss rate in reconstituted tobacco sheets exceeded that of natural tobacco leaves. It was verified that calculated values from the Page model and measured values had a relative error of moisture content within 5%， which could better predict the moisture desorption behaviors of natural tobacco leaves and reconstituted tobacco in actual production settings.