【作者】 赵丽娜；

【导师】 孙卫东；

【作者基本信息】 广西大学 ， 制糖工程， 2008， 硕士

【摘要】 传统亚硫酸法制得白砂糖含硫量高,质量不够理想,而且随着新的白砂糖国家标准的出台,其弊端显得更加突出。为了加入国际市场的竞争行列,应谋求改进亚硫酸法工艺,生产出高质量的白砂糖,提高现有糖厂产品的产值,增加收益。根据我国国情,可以尝试一些过渡的新型澄清工艺,设备和方法来改善当前现状。本课题探索研究了一项制糖澄清过程的新型无硫澄清工艺,该工艺采用传统石灰法和新型阳离子蔗渣澄清剂相结合的方法,对甘蔗混合汁进行两步澄清应用研究。除此之外,还就该蔗渣澄清剂的吸附动力学、再生及澄清后糖汁的稳定性等方面进行了系统试验研究。由于此工艺不添加SO₂,成品糖中无残硫,并且成本较低,这将在糖液脱色和提纯方面取得全新突破。论文的主要研究内容和结果如下:1.依据单因素试验,设计了包括阳离子蔗渣澄清剂加入量、反应温度、接触时间和pH值四个重要因素以确定它们对澄清作用的影响情况。然后,在单因素试验的基础上,该论文又设计了正交试验并进行了结果分析。最优澄清条件如下:阳离子蔗渣澄清剂加入量0.4g/100mL清汁、反应温度80℃、接触时间40min及pH8。2.通过静态吸附试验,得出:表明脱色反应是以液膜扩散为主控步骤,即交换速率大小控制了在固-液界面上交换质的滞留时间,交换反应速率常数k=5.57×10^-3S^-1,并且该阳离子蔗渣澄清剂的脱色过程遵循Freundish等温式。通过动态吸附试验,得出:随着待脱色清汁样品流速的增大,脱色率降低;增加离子交换柱高径比,可提高脱色效果。3.最佳再生条件的研究:质量分数1%HCl+质量分数10%NaCl的组合再生剂,再生后澄清剂的交换容量损失少;在80℃时再生效果较好,解吸为吸热过程,提高温度利于解吸,但是温度太高时,可能由于澄清剂纤维在高温下发生化学降解和结构变化,导致脱色效果下降。4.清汁热稳定性研究及色素废水的处理:未经蔗渣澄清剂脱色处理的清汁热稳定性差,随温度升高色值上升很快。而脱色后的清汁在高温下较稳定,说明阳离子蔗渣澄清剂对色素的清除彻底,高温条件下不再产生新的色素物质。解吸出来的色素废水中不含蔗糖成分。因此色素废水可以用来冲锅炉煤灰,没有废液排出,符合环保要求。更多还原

【Abstract】 The white granulated sugar which made from traditional sulfitation process contains high content of SO₂, with poor qualities, and along with the establishment of new standard about white granulated sugar, its disadvantages become even more obvious. For the sake of joining international market, the sulfurous acid processe should be improved, then the qualities of white granulated sugar will be enhanced, as well as, the sugar-refinery products value and profit will be also improved. Based on the situation of our country, the transitional new clarified processes, equipment and methods should be tried out to improve the current condition.In this paper, the approach we explore is a novel sulfur-free clarification technics which is the combination of defecation process and cationic bagasse clarifying agent. It contribute to the gradual clarification of the sugar juice. In addition, a series of tests were carried out to study adsorption kinetics and rebirth of cationic bagasse clarifying agent, as well as the stability of sugar juice which was obtained by the new technics described above. In virtue of no accession of SO₂, we can gain sulfur-free sugar product. Besides, low cost is another merit we think a lot of. So it is remarked that this novel sulfur-free clarification technics might serve as a promising industrial protocol for sugar juice clarifying approach. The main research contents and results of the thesis are reported as follows:1. According to the monofactorial tests, four important factors including cationic bagasse clarifying agent dosage, react temperature, contact time and pH value were focus to ascertain their influence on defecatation effect. Whereafter, on the basis of monofactorial tests, the orthogonal design and results were presented in the paper. And the optimal clarification condition was found as follows: the cationic bagasse clarifying agent dosage 0.4g per 100mL preclarified sugar juice, react temperature 80°C, contact time 40min and pH8.2. According to static adsorption test, it indicate that liquid-film pervasion is the main control step of decoloration reaction. Namely, the retain-time of the exchange matters which are at the interphase is controled by the exchange velocity （k） that equal to 5.57×10^-3s^-1 numerically. Also, the decoloration process of catinic bagasse clarifying agent follows Freundish isothermal equation. And according to dynamic adsorption test, it educes that along with the enhance of velocity, the decoloration rate of sugar juice becomes much lower and when the length-diameter ratio increases the decoloration effect can be advanced. 3. The optimal clarification condition: combined regeneration agent of 1%HC1 and 10%NaCl which bears the merit of low loss on exchange capacity. On account of decalescence during regeneration at 80℃we can achieve regeneration of cationic bagasse clarifying agent preferably. Yet if the temperature is too high, meybe cause the decline of decoloration effect as a result of chemical decompose and mutative structure.4. Thermal stability of clarified sugar juice and disposal of pigment waste: the sugar juice which is not decolored by cationic bagasse clarifying agent possesse a trait of poor thermal stability and when it heats gradually the color value may increase soon. However, the sugar juice which is decolored by cationic bagasse clarifying agent is stable which means the removal of pigment is complete and there give birth to no pigment on the condition of high temperature. The pigment waste contains no sucrose, so it can be used to wash boilers, and meet the need of protection of environment.更多还原