为了大幅降低蔗糖厂蒸发工艺的能耗,首次将蒸汽喷射式热泵技术、冷凝水闪蒸和引出额外蒸汽预热糖汁等3种节能措施,同时运用于糖汁浓缩并流多效蒸发系统中,并建立了用矩阵方程描述的该系统的数学模型.模型具有很强的通用性,可实现上述节能措施的自由组合和热泵在任意效抽汽的功能,还可推广用于食品工业其它热敏性溶液的蒸发浓缩;模型存在最佳的热泵喷射系数和抽汽位置,同时采用上述3种节能措施且在最佳条件下可以高效节能.用迭代法结合矩阵法求解浓缩糖汁的热泵并流四效蒸发系统的模型,结果表明,同时采用上述3种节能措施,并在满足约束条件的前提下,将糖汁预热至90℃,热泵的喷射系数为0.5,抽汽位置在第2效时节省的生蒸汽消耗量高达41％左右.

为了全面提升布谷鸟搜索算法(CS)的性能,提出了一种改进的布谷鸟搜索算法(MCS).MCS算法采用了能大幅提高局部搜索能力的局部搜索策略、能使步长控制因子随算法进程由大到小自适应变化的自适应策略和能加强布谷鸟个体间信息交流的学习策略.2个标准测试函数被用于检验算法的性能,性能测试结果及对比试验表明,MCS算法在继承了CS算法强大的全局寻优能力的同时,具有更快的收敛速度、更高的收敛精度和更好的鲁棒性.最后,将MCS算法应用于求解多效蒸发系统的优化设计问题,优化效果显著.

In order to greatly reduce the energy consumption of fruit juice concentration process, a general mathematical model of countercurrent multiple effect evaporation (MEE) system contains various energy saving measures simultaneously (such as steam jet heat pump technology, solution flash and condensed water flash) is established in this paper. The systematic material balance equations and heat balance equations are described as the form of matrix equation to realize the generality of this model. The general model can be simplified to a countercurrent multi-effect evaporation model contains several or none energy saving measures and it can achieve the function of pumping steam at any effect. The model is solved by matrix method combining with iteration method, which has advantages of less sensitive to initial values, high convergence speed and stability. The developed model is used to simulate the fruit juice concentration process under different operating strategies. The simulation results indicate that heat pump is an effective energy saving measure in countercurrent MEE system. The larger values of ejection coefficient and effect for pumping, the more fresh steam consumption saves and heat transfer area increases when some constraint conditions are satisfied. After combining condensed water flash and solution flash, it achieves a more pronounced effect. (C) 2014 Elsevier Ltd. All rights reserved.