维生素低温蒸发结晶单元的自回热设计及分析

Advanced energy saving in vitamin evaporation crystallization section at low temperature with self-heat recuperation technology

针对传统维生素生产过程中的蒸发结晶单元耗能高、排放量大的特点,提出了一种基于自回热原理(self-heat recuperation technology,SHRT)的改进设计。利用能量分析和?分析的方法对系统进行分析。并研究了最小传热温差的特性,以及压缩机的绝热效率和闪蒸进口过热度对系统能耗的影响。结果表明,利用自回热思想改进的蒸发结晶单元比传统过程所需的输入能减少了73.0%,输入?减少了68.3%。在文中的条件下,潜热比显热有更大的利用空间,利用的潜热占总循环热量的93.5%。同时,最小传热温差的增大虽然会使需要的换热器的面积减小,但也会导致更大的能量输入。系统的能耗随着过热度的增大而增大,随着绝热效率的增大而减小。

To solve the problem of high consumption and great emission of the evaporation unit in production of a vitamin, an advanced process is proposed based on the self-heat recuperation technology. The sensible and latent heat of the effluent stream is recuperated and reused to heat the inlet stream of flash evaporator by vapor recompression without any heat addition. The advanced process is evaluated by energy and exergy analysis. The relation between energy consumption and the minimum heat transfer temperature difference are studied, as well as the effect of adiabatic efficiency on energy required. The results indicate that the advanced system with self-heat recuperation technology is able to save great energy and exergy. The energy input is decreased by 73.0% and the exergy input is decreased by 68.3%. There is a larger potential space for latent heat than sensible heat, which only accounts for 6.5% of the total heat recycled. Although larger minimum temperature difference needs less heat transfer area, it requires more energy input. Higher adiabatic efficiency and lower superheat mean less energy required.