Evaporation compression startup and control
Start Compression evaporation model with default parameters. The objective of this exercise is to start the installation and set it to produce a 20% mass fraction concentrate from a 7% mass fraction feed
- Fully open reboiler shell degasing valve to atmosphere
- Start centrifugal compressor at 10% power, follow suction and discharge pressure, and look at anti-surge controller (mini-flow)
- Controlling suction and discharge pressure, increase compressor power to reach boiling in the evaporator
- When boiling occur, maintain inert purge to atmosphere until condensation begins
- Increase slowly compressor power up to 80%
- Set condensate level controller to automatic mode and start condensate pump
- Feed evaporator to keep bottom level constant until concentrate mass fraction objective of 20% is reached
- When evaporator concentrate is at objective, feed evaporator to keep this concentrate composition
- When installation is in steady state, check global and partial mass balances
- Check the energy balance, comparing various heat flux: feed pre-heat, vaporization in evaporator, condensation on condenser shell side, compressor power
- Calculate evaporator economy (or performance coeficient) as the ratio between power given to evaporator and power used by centrifugal compressor
Page précédente : Double effect evaporation startup and control
Page suivante : Reaction