General Information Deck 1 Flashcards
Air Products & Praxair could be set on ________________ or __________________ control depending on make, take or pay contracts.
Pressure or Flow
Air Products normal pressure set point ranges between ____________ & ____________ psig when on flow control.
(this can change based off complex needs)
240 & 245 psig
Praxair Normal Pressure setpoint while in flow control is ______________ psig.
250 psig
To make a change to the Air Products or Praxair pressure set point we must ___________________.
Call Air Products or Praxair and make the request.
What does WABT stand for?
Weighted Average Bed Temperature
Which Units is WABT most important? Why?
- 633 & 635
- Because these units produce a final product
Normally it takes approximately ________________ minutes for feed to work its way thru the units.
45 minutes
Name the 2 primary ways a console operator will know that there is an increase in the sulfur content of the feed being sent to their units.
- Sulfur Indication in the product produced on the back-end of the unit (sulfur analyzer)
- Console operator providing feed to your unit can provide you a verbal warning if they are aware of issues on their complex.
If sulfur content of the feed being sent to your unit begins to rise what is the primary mode to treat high sulfur feed?
- Increasing the WABT in the Reactor is the primary mode of treating feed with higher sulfur concentration
What is a secondary method of treating feed with an increased rate of sulfur content? Why is this usually not an option?
- Increase Hydrogen Partial Pressure
- Usually we try to run units MAXED on Partial Pressure
What is Hydrogen Partial Pressure?
- A calculation of the amount of Hydrogen vs the amount of feed & the hydrogen purity being sent thru a unit
Why is it preferable to run units on MAXED Partial Pressure?
- Maximizing partial pressure, reduces the temperature in the Reactor needed to treat feed. By reducing this temperature in the reactor we can extend catalyst life.
Which streams are normally rated by 95% point?
- Feed Streams
Which streams are normally rated by 90% point?
- Product Streams
Define 95% Point:
- the temperature in which 95% of the product burns off
Define 90% Point:
- the temperature in which 90% of the product burns off
For Tank Spot testing:
- 90% point has a set point of:
- 640 degrees maximum
For Tank Spot testing:
- Final Boiling Point (FBP) has a set point of:
- 680 degrees maximum
For Tank Spot testing:
- Sulfur target is ________________ & is Off Spec @ ______________________.
- 9.00 ppm
- 10.00 ppm
For Tank Spot testing:
- H2S target is ________________ ppm & anything over _________________ is considered Off-Test.
- 0.0 ppm
- 0.0 ppm
Define Diesel Flash Point:
The point in which the product ignites or becomes combustible
Define Cloud:
- the visual clarity of a product stream
For Tank Spot testing:
- Cloud Stream set point is: ____________________
- 14 - 15 degrees Fahrenheit
When we go into a new tank we document the following:
- Tank Number
- Date & Time
- Heal
- Target
- Total
Define Tank “Heal”.
- Level in a tank when we swap into the tank.
Define Tank “Target”.
- How much we plan on flowing into the tank
Define Tank “Final”.
- Total product to be in tank after we reach our target goal (Heal + Target = Final)
List 634 Feed Sources. (5)
- 634 Cold Feed From Tank (64FC0017.PV)
- 536 Total HVGO Product Release (56FC0068.PV)
- 536 Hot HVGO Product Release (56FC0285.PV)
- 537 MVGO Product to 634 (57FC0046.PV)
- 537 HVGO Product to 634/636 (57FC0048.PV)
List 636 Feed Sources. (4)
- 636 Cold Feed From Tank (64FC0117.PV)
- 536 Hot HVGO Release (56FC0285.PV)
- 537 MVGO Product to 636 (57FC0148.PV)
- 537 HVGO Product to 634/636 (57FC0048.PV)
List 633 Feed Sources. (9)
- Off-Test Diesel / Tank 609 (Mis-Labeled Tank 619) (63FC0244.PV)
- Off-Test Diesel / Tank 100 (63FC0245.PV)
- 536 Cold Diesel Product Release (56FC0129.PV)
- 536 LVGO Product (56FC0102.PV)
- 537 Diesel Product (57FC0090.PV)
- 537 LVGO to 633 / Tank 594 (57FC0201.PV)
- 636 Diesel Product to 633 (66FI0040.PV)
- 636 Frac OH Product (Naptha) (66FI0055.PV)
- 633 LCGO (Coker Feed) (66FC0237.PV)
List of 635 Feed Sources. (7)
- Off-Test Diesel / Tank 100 (65FC0200.PV)
- 536 Hot Diesel Release (56FC0059.PV)
- 536 LVGO Product (56FC0102.PV)
- 537 LVGO Product (57FC0043.PV)
- 537 Diesel Product (57FC0150.PV)
- 636 Diesel Product to 635 (66FI0040.PV)
- 736 LGO (65FC0046.PV)
What’s the quickest ways to decrease hydrogen consumption on HDS units (633, 634, 635 & 636)
- Drop unit pressure (10-30 psi ; 10 psi intervals)
- Divert Crack-Stock from units (Coker Feeds & Cold Feeds)
Which of these are associated with trip points?
DCS or SIS
SIS
Which of these are associated with standard alarm points and won’t trip equipment?
DCS or SIS
DCS
636 Unit
F-1 Heater: If you lose H2 to all 4 passes it will trip heater.
True or False
True
(Review IP21 to confirm)
636 Unit
F-1 Heater: If you lose H2 & Feed to a single pass it will trip heater.
True or False
True
(Review IP21 to confirm)
636 Unit
F-2 Heater: If you lose feed flow thru any pass it will trip heater.
True or False
True
(Review IP21 to confirm)
BMS stands for:
Burner Managment Systems
MV’s are typically _____________.
Flow
CV’s are typically ______________.
Level
9 times out of 10 Air Products is in _______________ control.
(This year in 2023)
Pressure
9 times out of 10 Praxair is in _______________ control.
(This year in 2023)
Flow
Lowest suggested PC-21 Hydrogen Pressure Setpoint is ____________.
257psi
What tool would we use to confirm if an alarm is DCS or SIS?
Cause & Effect Matrix
Define MEASTOL (Measureable Tolerance)
Amount of deviation allowed before alarm
Define MEASDB (Measurable DeadBand)
Amount of correction needed before alarm will clear
Which 3rd party H2 provider buys Channelview H2, cleans it and resells back to us?
Praxair
If reactor is cold, we run the risk of ending up with higher/lower sulfur in final product?
higher
Where does H2S come from in our process?
Two Hydrogen molecules bond with One Sulfur molecule inside the Reactor (Chemical Reaction) to form H2S.
After being created in the process, H2S begins separating from the liquid product how?
Pressure drops in various vessels (depending on units: strippers, hot flash drums, cold flash drums, product separators, fractionators) allows the separation of H2S rich Hydrogen in the overhead flows, from liquid product in the bottom flows.
H2S rich Hydrogen flows have H2S removed from the hydrogen streams how?
The Gas contactors remove H2S from the Hydrogen with the cross-flow of lean amine and H2S rich hydrogen. The resulting rich amine (h2s rich) is sent to the SRU for regeneration back into lean amine. The resulting hydrogen is recycled back into the unit
633 Unit
What are the 2 primary moves to adjust backpressure regulator issues?
- Manipulate H2 Bypass around the Heater
- Add or Remove a Make-Up Load on the compressors
633 Unit
Adding or Taking away a load will adjust H2 flow by ~ ________________ MSCFS
350
635 Unit
Adding or Taking away a load will adjust H2 flow by ~ ________________ MSCFS
250
On IP21, White Regulators are in ______________
DMC
On IP21, Blue Regulators are in ________________
Cascade
Cascaded regulators are (subordinate or master) regulators
subordinate
634 & 636 Unit (VGO Treaters)
How can we clear H2S out of product on our VGO treaters?
Increase Stripping Steam. (You can’t adjust temperature or pressure on these units)
How many pre-heat temperature controllers are on 633 unit?
3
How many pre-heat temperature controllers are on 634 unit?
0
How many pre-heat temperature controllers are on 635 unit?
2
How many pre-heat temperature controllers are on 636 unit?
1
What is the approximate WABT High Limit for all Heavy HDS Reactors?
730 degrees
Why is a feed’s 95 degree results important?
The higher the 95 degree feed results, the higher we need to get temp in the Reactor to treat the feed & the more/quicker we kill catalyst
What is/are the stripping medium(s) & vessel(s) in which stripping takes place on 634 unit?
Steam utilized in Stripper
What is/are the stripping medium(s) & vessel(s) in which stripping takes place on 635 unit?
Nitrogen(N2) & Natural Gas (NG) utilized in Stripper
What is/are the stripping medium(s) & vessel(s) in which stripping takes place on 636 unit?
Steam utilized in the Stripper & Fractionator
What is/are the stripping medium(s) & vessel(s) in which stripping takes place on 633 unit?
Hydrogen(H2) & (Heat) utilized in the Stripper
What is the “preferred” method for controlling product flash point?
Pressure manipulation (increasing/decreasing frac/stripper pressure)
What is the 90 degree product spec?
Temperature @ which 90% evaporation occurs
How can you reduce the 90 degree point product test results?
Increasing overhead pressure of tower will force more light ends into the bottom of the tower and final product which will reduce our 90 degree point results.
What is the desired 90 degree point product spec range?
600 - 640 degrees
634’s CFD liquid into the Stripper acts as what?
a liquid coolant to control Stripper temperature
1st Stage Spillbacks on all compressors are primarily used for what?
To regulate the amount of H2 that we are pulling into the units.
Explain how the 1st stage spillback works on compressors.
When the 1st stage spillback is opened it brings compressed hydrogen to the front end of the 1st stage suction line, this creates head pressure that backs out make-up hydrogen from the plant header
When the 1st stage spillback is closed it pushes more compressed hydrogen forward into the unit and allows more make-up gas to flow into the unit from the plant header
635 Unit
Explain how the 2nd stage spillback works on the 635 unit.
Opening the 2nd stage spillback on the 635 unit allows compressed recycle hydrogen to flow into the suction of the Make-up 2nd stage which is then compressed and pushed into the unit; more H2 will go to unit as we open the 2nd stage spillback.
633 2nd stage spillback is
rarely ever manipulated
How do you know when to load or unload the compressor on the 633 unit?
633 will load or unload the compressor based on the H2 needs of the 634 & 636 unit. If we need to increase H2 purge to these units we can add load to the compressor which will allow us to purge more off the back of the unit. * We can also close 1st stage spillback to take in more gas from plant header which will also increase our purge on the back of the unit*
How do you know when to load or unload the compressor on the 635 unit?
635 will load or unload the compressor based on the H2 needs of the 634 unit or based on whether or not we are purging excessively to the plant header.
636 Unit
Explain the relationship between PC8 (Unit Pressure Regulator) & MGC 3rd Stage Spillback:
PC8 controls the position of the 3rd stage spillback. The 3rd stage spillback adjusts itself to maintain the set point for unit pressure.
636 Recycle compressor can or can’t adjust its RPM’s.
Can’t
634 Compressor can or can’t adjust its RPM’s.
Can
RPM’s can be adjusted to increase or decrease __________________.
Flow
Hydrogen Header is where:
The 3 Hydrogen providers join together.
Plant Line is where:
Hydrogen purges are sent to.
How does Hydrogen System (38PY0022) Switch work when PC0022 is lined up?
Under this configuration the valve is purposed to maintain a set back-pressure on the High Purity Header.
How does Hydrogen System (38PY0022) Switch work when PC0040A is lined up?
Under this configuration the valve is purposed with maintaining the plant line set pressure by opening and closing the High Purity Flow into the plant line.
Purging H2 to fuels impact the refinery __________________ values
BTU
What units does the 635 Cooling Tower Feed?
Fluid, BBC 637 & 236
Cooling Water High Temperature Alarms @
95 degrees
Cooling Water Low Pressure Alarms @
55 psi
Cooling Water Pressure Set Point @
78 psi
High HRVOC Alarm is a Priority ___________ alarm?
1
What are two things you must do if High HRVOC’s are identified in the cooling tower
- Inform Chief
- Start taking bag samples
How do you respond to High Sulpur in Final Product?
Increase WABT
How do you respond to High H2S in Final Product?
- Increase Final Product Tower (Stripper/Fractionator) Temperature
- Lower Final Product Tower (Stripper/Fractionator) Pressure
Diesel Spec:
- IBP Deg F = Initial Boiling Point
Temperature at which the first drop of diesel vaporizes (Distillation obtained). Measures the volatility and quality of diesel
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- T10 (10%)
Temperature at which 10% evaporation occurs
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- T50 (50%)
Temperature at which 50% evaporation occurs
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- T90 (90%)
Temperature at which 90% evaporation occurs
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- FBP = Final Boiling Point
Temperature at which the highest boiling compounds evaporates
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- Residue Volume
Tendency of a fuel to form carbon deposits (coke) deposits under high temperature conditions in a inert atmosphere
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
-Fuel Loss Volume
Refers to the amount of fuel that is lost or wasted during various stages of production, transportation, storage & consumption
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- D976 2pt
Calculation of the cetane index of distillate fuels, such as diesel. The centane index is a measure of how easily the fuel ignites in a diesel engine
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- Pour PT F & Pour PT C
The lowest temperature at which diesel can still flow. (Affects the performance of engines in cold weather
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
-Cloud PT F & Pour PT C
The temperature at which wax crystals start to form in the fuel, making it cloudy and potentially clogging the fuel filters and injectors
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- Deg API
measurement of the density or specific gravity of diesel fuel
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- Density @ 60F
measurement of the density of diesel fuel at a standard temp of 60 degrees F
Density affects the performance & handling of diesel engines
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
-Color ASTM
Measuring the color of diesel fuel using a standard color scale. Color can indicate the quality, purity, and composition of the product
Feed Slate Change is the only thing that can improve this spec
Diesel Spec:
- PM Flash PT F
The lowest temperature in which diesel can form a flammable mixture with air. important for safety, quality & environmental reasons
Increasing Final Product Stripper or Fractionator pressure
What are three responses to plant Hydrogen Loss?
1st.
- Cut 537 MVGO feed from 634 & send to tank
* This is the easiest feed to divert; Just verbally tell the 537 Console Operator
* Try and pull feed from 634 because it’s easier to put on circulation
* This move will take time to impact loss of hydrogen
* This move helps because less feed requires less hydrogen
2nd.
- Drop unit pressures accross all 4 units (~10 PSI drop on each unit was discussed)
* 634 unit could experience level swings if pressure dropped too low
* Dropping unit pressure will help Hydrogen Header loss by “shrinking” ballon, requiring less pull on header
3rd.
- Lower WABT on 634 & 636 units
* Reducing RX temps on these units reduces Hydrogen needs for the units and pulls less from header (Less RX in the Reactor)
If your sulfur analyzer is above __________________ from lab sample then we have to do the following steps.
- 5 ppm
Steps
1. Resample
2. Write Notification if resample still has a deviation greater than 5 ppm
3. Monitor Tank Sulfur more frequently to ensure tank still sellable.
4. Turn Off Sulfur analyzer in DMC
5. Run the unit off WABT SetPoint
What is CVEUHI (Change Value High Limit)
Prevents you from mistakenly making a large change
Why do we control unit pressure off of the CFD instead of the Reactor Pressure?
To allow Reactor pressure to float so that it can remain as high as possible.
