Friday, 13 August 2010

Storage and Mixing Vessel - with em's and phases

Responding to the initial version on the Process Automation Modelling LinkedIn Group, we have

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  • Group: Process Automation Modelling
  • Subject: New comment (1) on "A combined storage and mixing vessel"
I think the design is flexible and not unique. See my quick idea as below:

(Physical Level)
Unit: UNIT (TK101)
EM: EQM01 (XV911, XV912, XV913, XV914), EQM02 (XV101, XV102, XV103), EQM03 (XV104, XV105, XV106, P102)
CM: VALVE (XV101-XV106, XV911-XV914), MOTOR (M101, P102), TRANSMITTER (WT101, TT104), DI (LSL102)

(Procedure Level)
Phase: AGIT PHASE (agitator), JCKT PHASE (jacket), TXIN PHASE (tank transfer in), TXOT PHASE (tank transfer out), WGHT PHASE (weight)

(Equipment Phase Logic in Controller):
AGIT PHASE: Use agitator on-off command, motoe speed setpoint etc. phase parameters to control M101 start/stop and speed. LSL from WGHT PHASE can interlock the agitator for protecting purpose.

JCKT PHASE: Use Cool, Heat, temperature setpoint etc. phase parameters, and operate EQM01 valves matrix, compare with TT104, to control tank temperature.

TXIN PHASE: Use source route setpoint (eg. 1=Solvent, 2=Upstream1, 3=Upstream2), quantities setpoint etc. phase parameters and operate EQM02 valves matrix, compare with WT101, to transfer liquid into tank.

TXOT PHASE: Use destination route setpoint (eg. 1=Down Stream, 2=Drain), quantities setpoint etc. phase parameters and operate EQM03 valves matrix, compare with WT101, to transfer material out from tank. LSL from WGHT PHASE can also interlock the P102 for protecting purpose.

WGHT PHASE: Use LSL setpoint, density setpoint etc. phase parameters to monitor level and generating LSL alarm message etc.

I think for process engineer, it will be easy to combine these phases and create the different type recipes.

Here is a diagram with the equipment modules and phases shown

1 comment:

  1. Francis -
    I am puzzled and need some clarity on a couple (or more) points.
    1. May I presume that EQM01 is a generic EM (no equipment phase)? If not, what is its procedure?
    2. I can see no reason at all for EQM02. It looks like three control modules to me. If solvent is an infinite source (open the valve and you have solvent) that works pretty nicely as a gain-in-weight algorithm within the reactor itself. However, it looks to me that Up stream 1 and Up stream 2 (presuming they are units) would like to have some control of the transfer. If that is the case, I think the valves would belong to the upstream unit(s) - with proper interlocking to make sure the valves cannot be opened unless this reactor unit wants to allow it. EQM03 looks like a very workable way to drain independently or transfer on request from the downstream unit.

    Am I in left field or was this a test to see if we are paying attention? :)