Sub:  Our Comments on Control Philosophy prepared by Techno Force (TF)
 
Ref:   P&I Diagram PIA 911, Rev P1 for ATFE
 
 
1)  TF to specify the operating parameters for process streams and utilities like
     flow rate / pressure / temperature at preheater, degasser,  ATFE and DCT.
 
2)   ATFE Feed Pump P 9213 A/B shall be metering type.  Hence control valve
     on feed line is not required.
 
3)  Temperature at V 9217 / V 9218 / V 9219 / V 9219A to be specified.
     Is temperature in these vessels to be controlled?  For these vessels, heating
    in jacket with MPS (8 kg/cm²g) has been shown based on discussions with
    TF on 6-4-11.  TF to confirm if LPS (3.5 kg/cm²g) or hot water at 70 deg C can be used instead.
 
4)  As per email dated 12-5-11 from TF, Degasser pressure is 20 mm Hga and
    ATFE pressure is 1 mm Hga. PIA 911 shows a common vacuum pump
    J 9112 A/B for Degasser and ATFE.  TF to suggest if any controls are
    required to achieve two different operating pressures with a common  vacuum
    pump.
 
5)  As per email dated 12--5-11 from TF, the pressure at Receivers is 5-10 mm Hga.
    However, as per the Control Philosophy, there is a water ring vacuum pump in
    this system.  TF to confirm if the water ring vacuum pump is the same as
    the auxiliary vacuum pump J 9113 A/B shown in PIA 911.
 
6)  As per the Control Philosophy, there is a Dissilate Pump PU-107.  It is
    not shown in PIA 911 Rev. P1.  It is proposed to drain distillate from V 9219A
    to V 9220 by gravity every 2 hrs. instead of pumping it out.  TF to confirm
    their agreement.
