Waste Water Heat Recovery And Utilizationin Technology Research In Shengli Oilfield

Waste water heat in the oilfield is abundant,as well as has great usage potential.Absorption heat pump can directly use the heat source,and send the heat from a low temperature to a high temperature sources.Thus it's an effective mean to recycle low level heat energy that have the function of energy saving and environmental protection.Four kinds of waste water heat recovery system are proposed based on the difference situation in Shengli oilfield,include direct heat exchange model,the first kind absorption heat pump model,the second kind absorption heat pump combined with the first kind absorption heat pump model and vapor-compression heat pump model.This article compares characteristics of the vapor-compression heat pump,the first kind absorption heat pump and the second kind absorption heat pump.According to the basic conditions of the project,the conclusion is that direct heat exchange model is suitable for station which has waste water temperature higher than 50?,absorption heat pump model is suitable for station has stable gas source and vapor-compression heat pump model is suitable for station has unstable gas source but enough power supply.In this paper,the thermodynamic calculation is finished about the first kind absorption heat pump,the second kind absorption heat pump and the high temperature vapor-compression heat pump.The effect of waste water temperature and feed water temperature are analysed.For high temperature vapor-compression heat pump,the effect of working liquid and exhaust superheat of compressor are also analysed.Exergy analysis is finished to find out the weak link in the system.We get the result that exergy loss of compresser and evaporator in high temperature vapor-compression heat pump,of generater and absorber in the first kind absorption heat pump,and of condenser and solution flash valve in the second kind absorption heat pump takes up a great proportion.We should try to diminish the exergy loss in these parts.We finished pinch analysis with question chart methond.Heat exchanger networks are optimized base on pinch methond.The optimized pinch point temperature differences is 20? for the fist kind absorption heat pump,and 4? for thesecond kind absorption heat pump.Then the change of average pinch temperature and minimum utilities load is explained.In the end,we introduce reformation process and operation effect in Ludong waste water heat comprehensive utilization project and Jingyaun waste heat utilization heating project.The conclusion is that waste water heat recovery and utilizationin technology is available and stable,as well as can make good economic benefit.