Post on 23-Feb-2016
description
CO2control system
Lukasz Zwalinski – PH/DT17.06.2010
There will be one PCO with 3 option modes driven by allowance table
Plant operation
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Stop Stand-By RunStop x 1 x
Stand-By 1 x 1Run 1 1 x
Switch between modes is executed manually by the operator request.Stop (Option Mode 1)
All devices are in safety position.
Stand-By (Option Mode 2)Operator can safely move system from “warm” environmental conditions to the state where accumulator is cooled down.
Run (Option Mode 3)Run is defined as an option in which plant is fully operated and tested structure can be entered with certain inlet enthalpy.
PCO is in run OrderOne PCO Alarm is blocked
Push button to open sequencer panel
PCO is in manual mode
Current selected option mode
Plant operation
In option mode Stand-By we can distinguish stepper with 4 steps associated
2
Start up1
CO2 PCO
T2
Cool down loop
Safety position
3
0
Cool down accumulator
T3
T0
T0
T0
Start up request
Cool down request
Cool down accumulator request
T1
T0
Safety position – It is preparation step before plant start up. Before first operation accumulator will be filled up to 75% of volume. This step in P-h diagram Fig.3 is somewhere along 220C isotherm in the 2-phase region. Pump inlet temperature will be 220C. Pump head and system pressure will be about 60 Bar. In this step all objects are switched off.Start up – accumulator is heated up to 270C and the system pressure increase to the corresponding saturation pressure 67 bar. In the first stage of plant operation set-point selection has to be done manually by the operator. When this condition is fulfilled, loop should be filled with liquid and then pump might be manually switched on. The liquid level in accumulator will decrease.Cool down loop – once liquid circulation is achieved chiller might be switched on. Accumulator is still kept at high pressure and the condenser will sub-cool the liquid. This is important to assure that CO2 is out of the 2-phase region flowing sub-cooled liquid in to the pump.Cool down accumulator – starting the accumulator cooling spiral will drop the pressure and the liquid temperature to the desired set point. The vapor in the accumulator will condense; therefore the liquid level will start to increase.
Transition conditions:
T0 = Not Run Order OR Not Option Mode Stand-by
T1 = Run Order & Option Mode Stand-by
T2 = Run Order & Option Mode Stand-by & liq. circulation is achieved Pump ON & FT1901 > 0.0
T3 = Run Order & Option Mode Stand-by & TT1110 – 30C < TTsat(calculated from PT1104)
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
PCO alarms
PCO alarms:
Start interlock: all requests are blocked when ON, prevents the object from starting
SI1 – NOT Option Mode Selected; [0s delay] Temporary Stop interlock: sends OFF request to the object when ON (Resetting does not require the intervention of the operator except when in
manual or forced mode. If Run-order was active before interlock appear then after the elimination of interlock source Run- order becomes active automatically)
TS1 – NOT 24V PS01 Status OK; [0s delay] Full Stop interlock: sends OFF request to the object & waits acknowledge when ON (Restarting requires the elimination of the interlock and the
operator attending to do it. If Run-order was active before interlock appear then after the elimination of interlock source Run- order rest deactivated)
Run-order – indicate that the object start is requested and there is no interlock.
FS1 – NOT (Process Stop Button OK AND Process Stop OK); [0s delay] FS2 – Chiller Pressure Switch Low = 1 OR Pressure Switch High = 1 [0s delay] FS3 – Pump Thermal Switch TS1101 [5s delay]
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Accumulator Control
PT1103
Acc. Tsp
PC1104MV
SP
EH1104Out High limit
Out Low limit Low limit
High limit
0%
Dynamically calculated f(Rth)0 ÷ 100 %
PC1105
Out Low limit
Out High limitMV
SP
Psat(Tsp)
CV1104
Low limit
High limit
Dynamically calculated f(sub-cool)0 ÷ -100 %
0%
OutO
OutO
IF Out1 + Out2 > 0 Then EH1104 ActiveElse CV1105 Active
Analog Digital Object
Analog Digital Object
PWM
0÷100%PWM
0÷100%
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Accumulator Control
calculated every 5s
Thermal resistance:
thth
ththnew RR
OutHOutHRROutHOutHminmax
)(*max minmaxmin
CO2_B158_PC1104minRth 50 mK/WCO2_B158_PC1104maxRth 75 mK/WCO2_B158_ PC1104OutHmin 25 %CO2_B158_ PC1104OutHmax 100 %
subcool = Tsat(PT1103) – TT1110
Sub cooling:
LH
Lnew subcoolsubcool
OutLOutLsubcoolsubcoolOutLOutL
)(* minmaxmin
CO2_B158_PC1401scH 5 KCO2_B158_PC1401scL 3 KCO2_B158_ PC1401OutLmin -10 %CO2_B158_ PC1401OutLmax -100 %
PowerTAccuT
R satheaterth
_
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Accumulator Control
PowerTAccuT
R satheaterth
_
L.Zwalinski – PH/DT CO2 test stand control 17.06.2010
Logic
STOPStand-By
RunSafty
position Start-up Cool down loop Cool down accumulator
EH1101 Pump oil bath OFF OFF Reg TT1101 SP= Reg TT1101 SP= Reg TT1101 SP= Reg TT1101 SP=
EH1102 Dumper OFF OFF Reg TT1102 SP = Reg TT1102 SP = Reg TT1102 SP = Reg TT1102 SP =
EH1104 Accumulator OFF OFF Reg PT1103 SP=27C
Reg PT1103 SP=27C Reg PT1103 Reg PT1103
EH1301 Chiller OFF OFF OFF ON ON ON
EH1903 after supply/return HX OFF OFF OFF OFF OFF
IF TT1103 -20C ≤ Tsat(PT1105)
Positon request = (hrequested - h3) * Øm
CV1105 OFF OFF OFF OFF Reg PT1103 SP= Reg PT1103 SP=
Pump OFF OFF OFF
IF TT1110 – 3C < TTsat(calculated
from PT1104) THEN ON
IF TT1110 – 3C < TTsat(calculated
from PT1104) THEN ON
IF TT1110 – 3C < TTsat(calculated from PT1104) THEN ON
Chiller OFF OFF OFF Chiller = ON Chiller = ON Chiller = ON
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Enthalpy control
Øm = Qexperimet / (h5 - h4)
Qheater = (hrequested - h3) * Øm
It is not possible directly control the enthalpy in a PID loop.
The enthalpy can be derived from measured pressure and temperature only when the state point is present in the liquid phase which means that measured temperature should be at least 20C lower than calculated Tsat . Because the enthalpy of point 3 and 3’ (Fig.3) can be in the 2-phase area calculation procedure have to use previous measurements from state point 2 (Fig3.). The PLC is calculating enthalpy from measured temperature TT1103 and pressure PT1105 and it’s on only if TT1103 -20C ≤ Tsat(PT1105) is true.
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
PT to H conversion
50
100
150
200
250
300
0 10 20 30 40 50 60 70 80
Pressure (bar)
Enth
alpy
(kJ/
kg)
-50-45-40-35-30-25-20-15-10-50510152025
UNICOS user interface
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
Software preparation
SCADA server
Logic Generator
Instance Generator
Specyfication
SIEMENS PLC
UNICOS project creation:
1 – Exel specyfication preparation
2 – PLC hardware configuration
3 – PLC & PVSS instance generation
4 – Process logic programation
5 – Code compilation
6 – Loading to PLC
7 – Commisionig & operation
All generated files will be kept in Subversion Version Control (SVN) service.
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
L.Zwalinski – PH/DT CO2 test stand control system 17.06.2010
-Tsat, Psat-Enthaplpy serching method-SMS/Mail-…