| A large number of low-temperature waste heat will produce on the production process of sugar plant. Especially Evaporation final effect steam juice and vapor juice circulating water contained the huge of waste heat energy.This energy grade is low and is difficult to directly use. The recycled water were taken to the cooling tower and the recycled water contains heat directly discharged into the environment, have caused the local ecological environment from thermal pollution and wasted alot of waste heat,but also caused a certain amount of soda evaporative heat loss,and resulting in waste of water resource. If these part of the circulating water waste heat in the sugar can be recycled, it will bring enormous economic and environmental benefits to the sugar mills.Absorption heat pump(AHP) is a recovering the low-temperature waste heat to preparate the high-temperature heat circulatory system.AHP has been widely used in brewing, textiles, wood, food processing, petrochemical, desalination, power plant and metallurgical industries.If the waste heat of circulating water in the sugar plant can be recycled by the AHP,will has broad application prospects to improve the energy efficiency of sugar plant.Guang Xi Lai bin Yong Xin Sugar Co.conducted the project about recycling the waste heat of circulating waterin the sugar plant by the AHP in the 2013/2014 crushing season.The project is the first case of AHP application in the sugar cane. This paper relies on the project,The paper will optimize the AHP operating condition of recycling the waste heat of circulating water in the sugar plant.will analyze exergy efficiency of the heat pump heating way and tradition heating way for mixed juice,and will explore the AHP applies to the cane sugar plait economy.First, according to thermodynamic principles, the paper established the AHP energy balance equations and determined the optimal parameters and constructed the AHP operating conditions optimization model.Using the steepest descent method to solve the model by using MATLAB software,Looking for the operating conditions when system performance(COP) optimal,and studying the main parameters how to affect the heat pump properties.The results of model solving show that, In the heat pump system is completely non-destructive internal heat exchange, heating steam flow can be reduced to 3.012t/h,the heating temperature of the heat pump system of the hot water outlet up to 72.74℃, then the optimum value of the heat pump COP to 2.784.When the internal heat loss in the heat pump system under the conditions of 6%, heating steam flow can be reduced to 3.378t/h,the heating temperature of the heat pump system of the hot water outlet up to 72.61℃,then the optimum value of the heat pump COP to 2.453.Combining these optimization results show that the use of sugar circulating water heat pump system heat recovery still has a large energy saving space, indicating the direction of energy efficiency improvements for sugar, while sugar and technical innovation to provide a new energy-efficient methods and theory.Secondly,the paper established of relevant exergy model though the analysis of Absorption heat pump system and mixed juice two heaters,calculated the exergy efficiency of the heat pump system optimization before and after;compared the exergy efficiency of the heat pump heating way and tradition heating way for mixed juice.The results showed that the exergy efficiency of AHP system before and after optimization is 54.68%,89.6% respectively,after optimization to improve 34.92%.In actual operating conditions, the exergy efficiency of the secondary heating mixed juice with traditional heating method only 48.38%, while the use of heat pump mode exergy efficiency can reach 83.39%, compared with conventional heating methods improved 35.01%.Heat pump heating method can achieve better energy cascade utilization.Finally,the paper evaluated the AHP applies to Lai bin Yong Xin Sugar Co.in the 2014/2015 crushing season to recycle the waste heat of circulating water economy by the dynamic investment payback method.The results show that the dynamic payback period of the project (10.29 years)<equipment life (20 years), that is the 10th year that is profitable.the sugar plant can save the amount of bagasse 4879.55t in the entire crushing season after application absorption heat pump heat recovery system. Converted into improved 0.66% C the rate of bagasse package.According to the market price of 380 yuan bagasse/ton, can save about 1.854 million yuan of funds.the crushing season can reduce the amount of cooling water 34819.2t to the cooling tower,saved 64,400 yuan for add water.AHP system is applied to sugar plant for recycling circulating water heat has significant benefits. |
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