Process mode for the A7 example simulation

The objective of this mode is to provide a conceptual design that we can use to further refine process development. To meet the design requirements, we make the following specification changes in Process mode.

Heat exchangers

• For the HX1 heat exchanger, we calculate the heat duty (Duty) to specify the shell-side outlet temperature (Tso) at 43.5°C

• For the HX2 heat exchanger, we calculate the heat duty (Duty) to specify the tube-side outlet temperature (Tto) at 72°C.

• For the HX3 heat exchanger, we:

  • Calculate the heat duty (Duty) to specify the shell-side outlet temperature (Tso) at 38°C.

  • Calculate the cooling water feed rate (CWS1.W) to specify the tube-side outlet temperature (Tto) at 40°C.

• For the HX4 heat exchanger, we calculate the heat duty (Duty) to specify the tube-side outlet temperature (Tto) at 99°C.

• For the HX5 heat exchanger, we:

  • Calculate the heat duty (Duty) to specify the shell-side outlet temperature (Tso) at 38°C.

  • Calculate the cooling water feed rate (CWS2.W) to specify the tube-side outlet temperature (Tto) at 40°C.

Pumps

• For the P1 Pump, we calculate the pressure drop across the Pump (DP) to specify the outlet pressure (P2) at 827 kPa.

• For the P2 Pump, we calculate the pressure drop across the Pump (DP) to specify the outlet pressure (P2) at 690 kPa.

• For the P3 Pump, we calculate the pressure drop across the Pump (DP) to specify the outlet pressure (P2) at 1,724 kPa.

• For the P4 Pump, we calculate the pressure drop across the Pump (DP) to specify the outlet pressure (P2) at 862 kPa.

Conversion reactor

For the R1 reactor, we:

• Calculate the heat duty (Duty) to specify the outlet temperature (T2) at 55°C.

• Calculate the conversions of the base components in the second and third reactions (R1.Xrxn[2] and R1.Xrxn[3]) to specify the total reaction conversion of methanol and water (R1.X[MeOH] and R1.X[H2O]) at 0.93 and 1.0, respectively.

• Calculate the methanol feed flow to the reactor (MeOHFeed.W) to specify the molar ratio of methanol to isobutylene fed to the reactor (MEOH_ITBE_MOL_RATIO) at 1.

Columns

• For the T1 Column, we:

  • Calculate the BoilupRatio to specify the MTBE composition of the bottom liquid product (S7.z[MTBE]) at 0.995.

  • Calculate the condenser vapor fraction (VFcond) to specify the condenser outlet temperature (Tcond) at 43.5°C.

  • Calculate the pressure drop at each stage of the column (DPstage) to specify the total pressure drop across the column stages (DPCol) at 76.5 kPa.

• For the T2 Extractor, we calculate the fresh water feed to the Extractor (WMa.W) to specify the mass composition of the methanol in the top product (C4s.zm[MeOH]) at 10 ppmw.

• For the T3 Column, we:

  • Calculate the condenser vapor fraction (VFcond) to specify the condenser outlet temperature (Tcond) at 30°C.

  • Calculate the pressure drop at each stage of the column (DPstage) to specify the total pressure drop across the column stages (DPCol) at 69 kPa.

  • Calculate the condenser pressure drop (DPcond) to specify the condenser outlet pressure (Pcond) at 103.5 kPa.

  • Calculate the column diameter (Dcol) to specify the overall stage flooding factor (FFcol) at 0.8. This allows us to size the column to fit the desired flooding factor.

  • Calculate the RefluxRatio and BoilupRatio to specify the methanol recovery (MeOHRecovery) and the water recovery (WaterRecovery) at 0.995 and 0.9995, respectively.

Valve

For the XV1 Valve, we calculate the pressure drop (DP) to specify the outlet pressure (P2) at 241 kPa.