| Waste heat resource is seen as the fifth conventional energy sources,after coal,oil,gas and hydraulic power.Energy efficiency in the industrial production of our country is lower than that of foreign advanced level generally,which is partly because of the tremendous waste of waste heat.According to current situation of industrial waste heat and heat requirements,a new steam heat pump system used for recovering industrial waste heat was proposed in this paper,which was composed of a vapor compression type high temperature heat pump(VCHTHP)and an injector heat pump.The experimental results showed that,if the primary steam was superheated vapor of300?,3.5MPa and the secondary steam of 0.20-0.22MPa,then the compressible steam of which the condensing temperature is about 160? could be obtained,with the highest entrainment ratio of 0.39.The maximum efficiency of injector heat pump occurs in the design condition P_H=0.22MPa,P_C=0.6MPa,with a maximum value of0.31,and the farther from design condition,the lower the efficiency.Through a combination of the VCHTHP and injector heat pump,the whole heat pump system could recover waste heat from the industrial sewage of 80? to produce compressible steam,the condensing temperature of which is about160?,and the coefficient of performance(COP)of the optimum condition was 1.19.If the compressible steam talked above was used as the heating medium of the reboilers in a chemical industry,28%of the high pressure steam was saved compared with original heating mode,while the power consumption only occupied 34.8%of the recovered heat.Based on the experiments,the energy saving effect of this pump system was discussed.As to the same secondary steam pressure,the energy saving effect of this heat pump system rises with the decrease of compressible steam saturation temperature.It will save 50%of the heating steam if the saturation temperature was 140?,which realizes a remarkable energy-saving effect. |
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