MVR技术在液态奶蒸发系统中的应用

Application of Mechanical Vapor Recompression Technology in Liquid Milk Evaporation System

针对目前液态奶蒸发浓缩领域的能耗高、热效率低等缺点,提出了基于MVR技术的液态奶蒸发浓缩系统,设计了基于MVR技术的蒸发工艺流程,介绍了MVR热泵系统的蒸发工作原理;采用单效MVR热泵蒸发系统,对系统主要工作部件进行了设计计算;采用火用分析模型对系统及各个部件进行了能效分析;并对影响系统性能的主要参数:压缩比、蒸发温度进行了分析。应用结果表明该系统具有运行稳定、能耗低等特点;火用分析结果指出了系统在用能方面的薄弱环节及改进系统性能的方向;参数分析表明,当压缩比增大时系统的性能系数η和火用效率减小,而当蒸发温度升高时呈相反的变化趋势,因此,MVR乳品蒸发系统应尽量采用较小压缩比的压缩机和维持较高的蒸发温度。

Concentrating on the high energy consumption and low thermal efficiency in evaporation of liquid milk, the MVR evaporation concentration craft was proposed. The evaporation process based on MVR technology was designed and the evaporation working principle of MVR heat pump system was introduced. Main working parts of system were calculated and designed by using single effect MVR heat pump evaporation system. Analysis of energy efficiency of systerm and each part was carried on by exergy analysis method. Main parameters that affected the performance of the system such as the compression ratio, evaporation temperature were also analyzed. The application results show that the system has stable operation and low energy consumption. The results of the exergy analysis point out the weak links of the system in energy consumption and the improvement of performances of the system. The parameters analysis shows that the system coefficient of performance and exergy efficiency decreases with compression ratio increasing and increases with evaporation temperature rising. Therefore, the dairy MVR evaporation system should adopt compressors of small compression ratio and keep a high evaporation temperature.