Document aBXxN45rp3DNG5kB6zzY0qwDN
CHECKLIST ( ATTACHMENT 1 )
Record Number 460552
NOTIFICATION OF PROCESS CHANGE CHECKLIST T>ptChlnge M.jor Q Moderate [7] Minor
Originator:............... CoUeenlice------------ r>ate of Origination:.8/19/9.6______________________ ____ --
Proposed Date of Change .8/22/96_______ Area: ........ HydracMonnation-------- Followup Required: ID Yes H No I
Permanent
Temporary......... From -------------- To -------------- Temp MOCRetumed to Original Status: ID Yes DNo]
Description and Location of ChangeAdri.steam.toi.faexl.ratio.Mo.d.Y..control.lo..C.rfi0f).........
Impact on:
----
Type of Change;
Safety
column.
Alarm Instrument
Shutdown Point z Process Computer Control
z Loss Prevention
Addition or Removal ofEquipment Equipment/Matcrial Modification Piping Modification
1 Environment
Job Procedure
Chemical Other
Health
Pre-Modiflcation Checklist:
Applicable N/A
Initials
....... ....... .......
...x.. ...x.. ...x..
...... Consult piping and equipment specifications. Perform Reactive Chemicals testing. 8/19/96In-Progress?
...... Add materials involved to Toxic Substance Control Act (TSCA) inventory.
.......
...x..
..... Calculate impact on F&EI and CEI
.......
...x.. ...i...
...... Comply with Engineering Practices. Comply with Technology Center guidelines.
...... Comply with Dow LAD Environmental Project Checklist.
0 A
Coi^pj ^5466
.................
...i...
..............
Comply with Safety and Loss Prevention requirements.
T A'_
......
...i...
..... Consult maintenance. (Name) .............................................................................................................
......
...i...
..... Consult instrument and electrical technician.
(Name)..............................................................................................................................................
...X..
Consult parts technician. (Name).........................................................................................................
...X...
Evaluate and modify relief system. (Name) ......................................................................................
...X...
Contact Industrial Hygiene. (Name).....................................................................................................
...X...
Contact Process Engineering. (Name)...............................................................................................
...X...
Complete required reviews. (Name them).......
...x...
...X...
...X... ...X... ...X... ,,.x... ...X..
Consult Computer programming support (Name)
Consult Operations (Name) ............................. Contact Environmental (Name ).............................................................................
Champs work order (List) ..................................................................................
Review Trailing Needs With Operations Supervisors or Technologist (Name)
Consult With Quality Person to determine if product MOC Required
(Name)
Other ...........................................................................................................
Approvals^
Originate
LW
*tlp First Reviewer
(Before startups
i?'9
0 Final Reviewr
App Na
laturej? J Date
M..
........
..X...
..X...
...X... .*... ..X... ...X...
...X.*
..X...
Perform pre*startup audit.
.......
................ Instrument loop drawings
Complete or update training program.
................................ Electrical drawings.
Job procedures written and approved.
P&ID's, process flow sheets and plot plans updated.
Personnel trained on the change. Training Documentation Attached PYS PNo Dn |
Critical instrument checklist updated. MOD check sheet completed, computer code and documentation changed.
Complete and Update Plant Files and equipment files
___y //-----------
CHLORINATED METHANE PRODUCTS COMMUNIQUE'
Review & Initial
DATE: Tue, Aug 20,1996 FROM: Rizzo
SUBJECT: Please read the following attached changes made to system A AO(5Q3) - Steam to feed ratio was added__________________ AO(502) & AO(512) - ramp down when disabled
This form is used to insure the attached information is communicated to the appropriate plant personnel. INITIATOR: Place a check mark by the group(s) needing to review. "MPLOYEE: Please initial and date when you have reviewed and understood the material.
Day Staff
PERSONS NEEDING TO REVIEW
Coaches X
SOS's X
OS's
Loaders
Init. Date
Inin. Dale
Clebert __________ Cook J* td-L -C Breaux
/fit it Date
Init. Date
Init. Date
Bishop
Armand
Haney (Jk
Dugas
fht Beieler
)*: Bourg
Doucet
Kelley__________ Tice \ ,T ;
Day Oper.
Bickham ($)t lj/z Davis
Cook F.
Ekey
Instruments
McMurrav Michel Rizzo Taylor Witt
Init.
Donatto N
Grace
Cavalier
Date
Harrison
Grant "*' is-"*'- Jack
Gravouill^ YJir
Looney
Johnson Simonson
Jackson [X %-lJ Wolfe MetrejeaiT~|v ^ jft Vlillender
init. Date
Hunt $ J-J
Shanklin--------------
Young
Vavasseur_________
DO A 005467 CONFIDFNTIAL
System
C-600
Equipment Number
500
Can
Loss of Communications
If communications is lost between the VAX and the MOD, indicated by ALM(700) becoming true, the steam flow setpoint will hold the last value it had prior to the loss of communication. (See AC(1519))
When communications are restored, TA(51) & TA(52) values should be checked to ensure they are reading correctly before clearing the alarm.
Lead /lag Calculation
A lead / lag calculation was written, AC(1842) and AC(1843). This logic works like ramp code. Since feed increases/decreases can occur at a fast rate, to prevent the ratio calculation from resetting the steam flow setpoint at a fast rate, the lead lag ramps up/down to the incoming feed flow.
AK(503)
Since we use AK(503) during start up, logic was added to TERM(502) which require that the AK have a value greater than zero before termination. This prevent the logic from coming up on ratio control before the reactors are started up.
Also, alarm(514) will activate if seq(50) is in step(502) and AK(503) is equal to zero.
IF a high pressure condition exist which activates WARN(503), the steam will ramp down. When cleared, WARN(526) activates, notifying the board operator sets AK(503) equal to AC(576). This disables the steam to feed and clears the alarm. Once everything looks OK, you can go back to steam to feed ratio control by setting the AK to zero,
AO(502) & AO(512)
Presently, when AO(502) o( AO(512) are disable, the valves immediately close, swinging the level in the column. To prevent this, logic was written, which will ramp down the controller. See DC(1298) & DC(1299)
l
D0 A 0?5468 CONF T DFNT T Al
A
System
C-600
Equipment Number
500
AO(503) - C-600 Steam Control Valve
A steam/feed ratio controller was added to the steam controller.
C-200 & C-201 btms flows are being transferred from the PICSVAX to the mod as TA(51) & TA(52) where they are re-scaled from 25 to 25000 to keep the same scale factors that are on C-600.
Failure Logic
A type of failure logic for these flow has been written, DC(1257) & DC(1258). These DC's only become true if there is a sharp decrease in one or both flows. When a sharp decrease occurs, one of the above DC's will become true and hold the total flow calculation, AC(1846) at the value it had prior to the event, preventing the steam flow setpoint, AC(1519), from responding and disrupting the column operations even more.
When one of the DC* s activate WARN(515) will activate. To clear the DC you have to set DM(188) true. However, this shouldn't be done until a flow has been reestablished. When DM(188) is set true, the logic that initially set the DC true will line up with the actual flow, clear the alarm, and begin recalculating the new flow, thereby cutting steam to maintain the current ratio setpoint.
Enable Logic - DC(1254)
To enable the feed/steam controller, first make sure you are in step(503) or step(504), then check AC(1519) value to ensure that the calculated ratio steam flow setpoint is lined up with the current steam flow. Then set AK(503) to zero.
NOTE: The feed/steam has a minimum steam flow setpoint based on AP(1655). When
enabling the controller, if the calculation is below the minimum it will take the minimum
flow setpoint.
'
AK(504) is the steam to feed ratio setpoint which is currently set at a .2. If a ratio setpoint is set outside the parameters as set by AP(1651) & AP(1652), REQ(514) will activate
indicating and invalid setpoint. When the steam to feed is disabled, the controller will track the actual steam to feed ratio.
nO A 005469 CONFIDENTIAL