基于熔融层结晶+减压发汗的油脂高效分提过程关键技术理论基础的研究

Crystallization fractionation is the key step in top chain of the oil refining processing, which is considered as an important way to make full use of oil resources. To a certain extent, it determines the application field and the economic value of the oil. At present, the dry fractionation is widely used in oil refining industry. However, the disadvantages of this method are the poor controllability and hardness in solid-liquid separation, which will lead to high energy consumption, low efficiency and poor products quality. According to the former research, an high efficient oil fractionation critical technique was put forward based on the layer crystallization and decompression sweating and a research idea is also brought on fractionation process . In this research, the thermal and dynamics database of the complicated oil system during layer crystallization will be systematicly investigated. The nucleation, growth and sweating dynamics models for crystals layer will be also established and the phase behavior of layer crystallization process will be revealed. Furthermore, the density distribution function of triacylglycerol during the crystal layer growth and sweating process will be analyzed, which will light on understanding the mass transfer mechanism during the oil crystallization and the mathematical model of solid-liquid interface mass transfer will be established. Above theoretical research will provide basic data for the new layer crystallization combined with sweating process. The control theory and scientific base of complex oil system in the fractionation will be developed. This study will open a new path for the high efficient and recyclable use of oil resource.

结晶分提是油脂精炼加工顶端产业链的关键节点，是充分利用油脂资源的重要途径，很大程度上决定着油脂的应用领域及经济价值。目前工业上油脂分提多采用干法分提，但该法可控性差、固液分离不易进行，导致高能耗、低效率、分提物质量不高等问题。申请者在前期研究基础上，提出基于熔融层结晶+减压发汗的油脂高效分提关键技术并对其分提过程进行基础研究的思路。本申请通过系统分析油脂复杂组成体系层结晶+发汗过程的热、动力学基础数据，建立晶层成核、生长及发汗动力学模型,同时揭示层结晶过程油脂相行为。分析晶层生长及发汗过 程固液界面甘三酯的密度分布函数，揭示固液相界面甘三酯传质机制并建立固液相界面传质数学模型。通过以上基础理论研究，为油脂层结晶+发汗过程的控制提供基础数据群，深化油脂复杂体系分提控制理论并提供科学依据。本研究将为油脂高效利用及油脂资源的循环再利用开辟新途径。

结晶分提是油脂精炼加工顶端产业链的关键节点，是充分利用油脂资源的重要途径，很大程度上决定着油脂的应用领域及经济价值。目前工业上油脂分提多采用干法分提，但该法可控性差、固液分离不易进行，导致高能耗、低效率、分提物质量不高等问题。申请者在前期研究基础上，提出基于熔融层结晶+减压发汗的油脂高效分提关键技术并对其分提过程进行基础研究的思路。完成了棕榈仁油一元及二元体系熔融相平衡基础数据的测定及熔融固液相图的分析与绘制。研究了棕榈仁油的结晶动力学数据的测定与分析，得到棕榈仁油及其软、硬脂晶体生长方式及晶体生长动力学模型，为棕榈仁油熔融结晶过程的工艺控制提供了理论基础。完成了棕榈油族甘油三酸酯结晶过程晶体微观结构及晶型演化，分析了晶层生长过程亚稳多晶型的相互转化，完成了熔融层结晶介稳区测定及成核诱导期并进行成核数据的关联与分析。分析了不同甘三酯在晶层生长过程中的相互或协同作用机制。棕榈油甘油三酸酯具有典型低共熔相行为特征，棕榈油结晶过程甘油三酸酯的共结晶现象，导致结晶过程不易控制。测定层结晶过程固液相甘油三酸酯，脂肪酸组成，结合固液相甘油三酸酯组成，分析晶层甘三酯变化规律，建立了晶层生长动力学数学模型。完成了棕榈油层结晶过程导热系数的测定与分析，建立层结晶过程界面传质数学模型并进行了数据的模拟分析。完成了晶层发汗过程晶层厚度与汗液排出速率数据的测定，建立了汗液排出速度与温度梯度关系的数学模型。完成了棕榈油层结晶分提工艺设计，初始外层温度为38 °C和14 °C，优化得到熔点为19.79±0.14 ℃，20 ℃下的20 °C下固体脂肪指数为16.51±0.19%、碘价为61.2±0.17的较为理想的棕榈油软脂产品。基于36 °C的夹套温度和24 °C的结晶管温度的初始结晶条件以及30 °C和0.5 °C/h的发汗温度和发汗加热速率的结晶优化，可以得到熔点为45.65±0.37℃，20℃时固体脂肪含量为80.48±0.49%，碘值为35.80.15%的较为理想的棕榈油硬脂产品。该工艺设计为工业上棕榈油及其他油脂分提提供重要的理论指导。