Study On Energy Saving Of Concurrent Multiple Effect Evaporation With Heat Pump For Fruit Juice Concentration

Multi-effect evaporation(MEE)is the most important and the most widely used method in the fruit juice concentration process.But its energy consumption and operating cost are also taking larger proportion in the total production costs.In order to greatly reduce the energy consumption and enhance the economic benefit of enterprise,the following aspects have been studied in this paper.A general mathematical model of concurrent MEE system contains various energy saving measures simultaneously(such as steam jet heat pump technology,excess vapor elicitation to preheat the fruit juice and condensed water flash)is established in this paper for the first time.The developed model is expressed as the form of matrix equation to realize its generality.And then,the matrix method combining with iteration method is used to solve the conventional design model and the conventional operation model of concurrent MEE system.The experiment results show that the aforementioned three kinds of energy saving measures all have outstanding energy saving effect in the grape juice concurrent triple effect evaporation system.And the energy saving effect from high to low is steam jet heat pump technology,excess vapor elicitation to preheat the fruit juice and condensed water flash.Under some constraint conditions,it has a most obvious energy saving effect to use these three kinds of measures simultaneously in concurrent MEE system for fruit juice concentration,the annual flesh steam cost saves 38.41%and the annual total cost saves 36.19%.In order to rapidly and efficiently solve the complex optimization model of concurrent MEE system for fruit juice,the local search strategy,adaptive strategy and learning strategy are presented to modified Cuckoo Search algorithm(CS).And then,the Intelligent Search algorithm is obtained(ICS).The performance experiment results show that ICS algorithm has better overall performance and particularly applicable to solve some large-scale complex optimization problems.The optimization design model of fruit juice concurrent MEE system is established in this paper,in which the total annual cost is regarded as an objective function and the ejection coefficient of steam ejector heat hump uq,pumping position q,flesh steam temperature Ts,condenser temperature TK,outlet temperature of fruit juice in pre-heater tp,n,coefficient of temperature difference ?i and ?pj as decision making variables.And then,ICS algorithm is used to solve it.The results show that the annual flesh steam cost saves 48.73%and the annual total cost saves 46.31%,after optimized the grape juice concurrent triple effect evaporation system,which contains various energy saving measures simultaneously.Meanwhile,selecting ejection coefficient of steam ejector heat hump uq,feed rates of fruit juice FO and condenser temperature TK as decision variables and the minimum concentration cost as target,the optimization operation model of fruit juice concurrent MEE system is established.Similarly,ICS algorithm is used to solve it.The results show that optimizing the operation model of grape juice concurrent triple effect evaporation system can decrease the concentration cost.And the more energy saving measures adopted in the system,the smaller space can be optimized.Besides,after operation ptimization,the concentration cost of the system can be saved up to 16.53%.In conclusion,after creatively designed and optimized,the concurrent MEE system for fruit juice concentration is high efficiency and energy saving,which can bring better economic benefit for fruit processing enterprise.