Study Of The Pinch Design Method For Heat Exchanger Networks Based On The Oil Physical Properties

This thesis, use the system engineering theory as a guide, based on thermodynamic analysis,for the Linnhoff exchanger network pinch point design method is based on an average heat capacity flow rate within the temperature range to conduct the enthalpy balance calculation. The process not only failed to take into account the heat capacity flow rate changes with temperature, but also ignores the effect of heat loss to the heat exchanger network. Set tow oil atmospheric-vacuum distillation unit’s networks as examples, Proposed based on heat capacity flowrate, enthalpy and heat loss three new heat exchanger network pinch point design methods.(1)Proposed the based on heat capacity flow rate heat exchanger network pinch point design method, through studies of examples, we can see that considering the factor the flow rate of heat capacity change with temperature in the heat exchanger network,will impact the pinch point position、the minimum temperature difference, the number of heat exchanger and investment costs.(2)Proposed the based on enthalpy heat exchanger network pinch point design method.The results show that this method will make the minimum temperature、the public works more accurately,estimate the investment costs are closer to reality.(3)Proposed the based on heat loss heat exchanger network pinch point design method.The results show that this method will impact the pinch point position, utilities consumption and total cost greatly; have less impact on minimum temperature difference△Tmin.