Pinch technology Flashcards
Why is heat integration used?
-Reduces utility cost
-Improves energy efficiency
-A trade off between capital and operating cost of the plant should be achieved
What are examples of capital costs for a network
-Heat exchangers
-Material of construction
-Pumps and compressors
What are examples of operating costs for a network
-Fuel & steam import/export
-Power import/export
-Refrigeration loads & levels
-Steam loads & levels
-Pumping costs
What is interchange on a temp-enthalpy diagram?
Maximum amount of heat that can be exchanged between the process streams
What does overshoots show on a temp-enthalpy diagram
-Indicates the external heating or cooling requirements of a process (the utilities)
-Hot overshoot requires cooling and cold overshoot, heating
What targets should be considered to optimise MER design
-Zonal targeting
-Pressure drop targeting
-No. of exchanger units targeting
When use zonal targeting?
When two parts of a plant are physically separated and a long pipe runs between the two to exchange heat, high capital cost for the pipe
When use pressure drop targeting?
When the higher pressure drop caused by additional HXs and pipework is beyond the capabilities of existing pumps, additional pumps are required and therefore further expenditure
When use no. of exchanger units targeting?
Capital cost is dominated by the no. of units so for a HX network there is a strong incentive to reduce the number of matches (HX units) between streams
