What is the Num 2 Diesel Fractionator Bottoms System?
Why Do We Need the Num 2 Diesel Fractionator Bottoms System?
How Does the Num 2 Diesel Fractionator Bottoms System Work?
Fractionator Bottoms Pumps P-1607A/B
Fractionator Feed/No. 2 Diesel Product Exchangers E-1604A - D
No. 2 Diesel Product Cooler E-1608
No. 1 Diesel Stripper Reboiler E-1606
Fractionator Reboiler H-1602
Num 2 Deisel Fractionator Bottoms
Contents
What is the Num 2 Diesel Fractionator Bottoms
System?
Why Do We Need the Num 2 Diesel Fractionator Bottoms
System?
How Does the Num 2 Diesel Fractionator Bottoms
System Work?
Fractionator Bottoms Pumps P-1607A/B
Fractionator Feed/No. 2 Diesel Product Exchangers
E-1604A - D
No. 2 Diesel Product Cooler E-1608
No. 1 Diesel Stripper Reboiler E-1606
Fractionator Reboiler H-1602
Num 2 Deisel Fractionator Bottoms
What is the Num 2 Diesel Fractionator Bottoms
System?
What is the Num 2 Diesel Fractionator
Bottoms System?
The is a system of piping, valves, pumps, heat exchangers,
a furnace and associated instrumentation that provides the means to get the No.
2 Diesel/Fractionator Bottoms from the Fractionator, T-1601; to the
Fractionator Bottoms Pumps P-1607A, P-1607B; to the tube side of No. 1 Diesel
Stripper Reboiler, E-1606; through the Fractionator Reboiler, H-1602; to the
tube side of Fractionator Feed / No. 2 Product Exchangers E-1604A, E-1604B,
E-1604C, E-1604D; and No. 2 Diesel Product Cooler Intercooler, E-1608; and to
storage or reject.
Why Do We Need the Num 2 Diesel Fractionator Bottoms
System?
Why Do We Need the Num 2 Diesel
Fractionator Bottoms System?
The is needed to take the No. 2 Diesel Fractionator Bottoms
from the bottom of the Fractionator, T-1601; recover heat from it in the
Fractionator Feed / No. 2 Product Exchangers E-1604A, E-1604B, E-1604C,
E-1604D; use it to add heat to the Side Stripper, T-1602 in the No. 1 Diesel
Stripper Reboiler; heat it back up in the Fractionator Reboiler, H-1602; return
the heated product to the Fractionator, T-1601 where it is cooled off to make
final product out the Fractionator Bottoms; and then routed to
storage.
How Does the Num 2 Diesel Fractionator Bottoms System
Work?
How Does the Num 2 Diesel Fractionator
Bottoms System Work?
Note: With the unit feed in the summer being 100% DF2 from
the Crude Unit, there is no No. 1 Diesel (DFA) to separate out as there is in
the winter mode of operation. During the summer, the Side Stripper, T-1602 and
associated equipment will be idled. This will be discussed in the DDU Overview.
The Fractionator Bottoms Product (No. 2 Diesel) is pumped
from the bottom of the Fractionator, T-1601 by Fractionator Bottoms Pump,
P-1607A, P-1607B. During winter operations, part of the Fractionator Bottoms
Product off T-1601 flows through the tube side of the No. 1 Diesel Stripper
Reboiler, E-1606 where it is cooled by exchanging heat with T-1602 Bottoms,
which is circulating through the shell side of the exchanger. The remainder of
the Fractionator Bottoms Product is pumped by P-1607A, P-1607B to the tube side
of the Fractionator Feed / No. 2 Product Exchangers E-1604A, E-1604B, E-1604C,
E-1604D where it is cooled by exchanging heat with the Fractionator Feed, which
is flowing through the shell side of the exchanger and then goes on to the No.
2 Diesel Product Cooler Intercooler, E-1608 where it is cooled. The No. 2
Diesel Product then flows to storage.
The major components of the are the Fractionator Bottoms
Pumps P-1607A, P-1607B, tube side of the No. 1 Diesel Stripper Reboiler,
E-1606, channel head side of the Fractionator Feed / No. 2 Product Exchangers
E-1604A, E-1604B, E-1604C, E-1604D, Fractionator Reboiler, H-1602, and No. 2
Diesel Product Cooler Intercooler, E-1608.
The Fractionator Bottoms Product off T-1601 is No. 2
Diesel. This flows out of T-1601 through a vortex breaker and 10-inch line with
ANSI 150-lb. class flanges. This line off T-1601 has a 3-inch connection with a
block valve, a blind, and is piped up to the . It has a sight glass to visually
observe flow to the . The 10-inch line also has a 1½-inch connection with
TE-16155 that sends a signal to TI-16155 in the DCS. This indicates the
temperature on the Fractionator Bottoms liquid. Then the Fractionator Bottoms
piping splits into two 10-inch lines and the piping changes to ANSI 300-lb.
class flanges where on each branch there is a 10-inch block valve, a blinding
station and a ¾-inch bleed valve. Both 10-inch branches reduce to 8 inches and
flow into the suction of P-1607A, P-1607B.
Fractionator Bottoms Pumps P-1607A/B
Fractionator Bottoms Pumps P-1607A/B
The Fractionator Bottoms Pumps P-1607A, P-1607B are
centrifugal pumps with 200-hp electric drivers. They have local mounted
start/stop switches. Hand Switch, HS-16179 on P-1607A and Hand Switch,
HS-16180 on P-1607B indicate the run status in the .
P-1607A, P-1607B have 8-inch suctions and 4-inch
discharges. P-1607A, P-1607B use an API plan 23/52 seal flush. The primary
seal flush (API plan 23) uses a tap off the case and routes the seal flush
through a heat exchanger where glycol circulates through the shell, cooling
the No. 2 Diesel Product in the tube coil. The cooled No. 2 Diesel Product
is then routed to the primary seal flush. The secondary seal flush (API plan
52) uses a local mounted reservoir to circulate buffer fluid through the
secondary seal by thermo-syphoning. The cooler fluid, being denser, flows
from the bottom of the reservoir and the warmer fluid returns to the top of
the reservoir. The reservoir is vented to the through a restriction orifice.
This captures vapors released if the primary seal fails.
P-1607A, P-1607B have a ¾-inch bleed valve routed to
the off the bottom of the case. There is a sight glass on this line for a
visual verification of flow to the . P-1607A, P-1607B have a 2-inch
connection that ties into the line to the .
P-1607A, P-1607B discharge through a 4-inch pipe that
increases to 8 inches and has a ¾-inch bleed valve with a local mounted
PI-16177 on P-1607A and local mounted PI-16178 on P-1607B for local
indication of discharge pressure. There are 8-inch check valves in the
discharge piping to prevent backflow through P-1607A, P-1607B. The 8-inch
discharge piping has a ¾-inch bleed valve, a blinding station and an 8-inch
block valve. Both 8-inch discharge lines combine into a single 8-inch pipe,
then the flow splits and has a 6-inch connection where part of No. 2 Diesel
Product flows toward the Fractionator Feed / No. 2 Product Exchanger,
E-1604A, E-1604B, E-1604C, E-1604D. The other part of the No. 2 Diesel
Product flows through an 8-inch connection to the tube side of the No. 1
Diesel Stripper Reboiler, E-1606. On the 6-inch line, there is a ¾-inch
bleed valve on the piping prior to flowing into the top of the channel head
on Fractionator Feed / No. 2 Product Exchanger, E-1604D through a 6-inch
nozzle.
Fractionator Feed/No. 2 Diesel Product Exchangers E-1604A - D
Fractionator Feed/No. 2 Diesel
Product Exchangers E-1604A - D
There are four Fractionator Feed / No. 2 Product
Exchangers E-1604A, E-1604B, E-1604C, E-1604D which all function in the same
manner. The channel head inlet nozzle has a 1-inch and a 1½-inch connection
that are both blind-flanged. There is a ¾-inch plugged connection on the top
and bottom of the channel head. From the inlet nozzle, the No. 2 Diesel
Product flows through the tubes in the tube bundle inside the shell where it
is cooled by the Fractionator Feed flowing through the shell. The tube
bundle is a 4-pass “U tube” design. The channel head has internal pass
partitions that direct the flow through the first pass where the “U tubes”
return the flow through the second pass back into the channel head. From
there, it is directed into the third pass. The “U tubes” return the No. 2
Diesel Product through the fourth pass back to the channel where it flows
out the 6-inch outlet nozzle. The channel outlet nozzle of E-1604D is
connected to the channel inlet nozzle of E-1604C where TW-16290 is installed
in a 1½-inch connection. There is also a 1-inch connection that is
blind-flanged. The flow through E-1604C is identical to E-1604D. The No. 2
Diesel Product leaves the bottom of the channel on E-1604C through a 6-inch
outlet nozzle that has a 1-inch connection and a 1½-inch connection that are
both blind-flanged. There is a ¾-inch bleed valve on the 6-inch piping just
out of E-1604C and another ¾-inch bleed valve prior to entering the top of
the channel on E-1604B. The 6-inch inlet nozzle on E-1604B has a 1½-inch
connection with a local mounted TW-16153. It also has a 1-inch blind-flanged
connection. The flow through the bundle is the same as in E-1604D and
E-1604C. The channel outlet nozzle off E-1604B is connected to the channel
inlet nozzle of E-1604A where there is a local mounted TW-16288 installed in
a 1½-inch connection. There is also a 1-inch connection that is
blind-flanged. It then flows through the bundle in E-1604A and exits the
bottom of the channel head through a 6-inch nozzle that has a 1-inch
connection and a 1½-inch connection that are both blind-flanged. The 6-inch
outlet piping has a ¾-inch bleed valve and a 1½-inch connection for
and TE-16157 that send signals to
TI-16157 in the . This indicates the temperature of the No. 2 Diesel Product
after E-1604A, E-1604B, E-1604C, E-1604D prior to final cooling. The No. 2
Diesel Product flow then enters the No. 2 Diesel Product Cooler Intercooler,
E-1608 through a 6-inch connection with a blinding station.
No.
2 Diesel Product Cooler E-1608
No. 2 Diesel Product Cooler E-1608
The No. 2 Diesel Product Cooler Intercooler, E-1608 is
designed for 300 psig at 350 °F. The bay is 7 feet 4 inches wide and 32 feet
long and has an inlet and outlet tube header box with 210 finned tubes and a
return header box. The tubes are 1 inch OD. The No. 2 Diesel Product flows
through the tubes in 4 passes as directed by baffles within the header
boxes. On the return header box is a 1½-inch connection on the top and
bottom with block valves and blind flanges. The 6-inch inlet and outlet
nozzles each have two 1½-inch connections that are blind flanged.
The exchanger has 2 fans driven by 20-hp electric motors
with local start/stop switches mounted at grade. These fans are shared by
the No. 1 Diesel Product Cooler, E-1607. The fan motor on the inlet end is a
variable speed and the one on the opposite end is a fixed speed. The speed
on the variable speed motor is controlled by a Speed Controller, SC-16253 in
the . SC-16253 is linked to TIC-16240 in the DCS. TIC-16240 receives a
signal from TE-16240 on the outlet piping from E-1608. Vibration Switch
High, XSH-16254 sends a signal to the Vibration Alarm High, XAH-16254 in the
DCS if the vibration reaches a predetermined set point on the fixed speed
fan. Vibration Switch High, XSH-16255 sends a signal to the Vibration Alarm
High, XAH-16255 in the DCS if the vibration reaches a predetermined set
point on the variable speed fan.
There are air exhaust louvers on top of E-1608 to
control air flow and avoid freeze-ups. The louvers have a pneumatic actuator
TV-16322 to open and close them as necessary. The louvers on E-1608 are
controlled by local mounted TIC-16322.
The No. 2 Diesel Product exits E-1608 through a 6-inch
nozzle on the bottom of the header where there is a blinding station. On the
outlet piping there is FE-16237 and FT-16237 that sends a signal to
FIC-16237 for indication in the DCS of the No. 2 Diesel Product flow rate.
FIC-16237 sends a signal to FY-16237 to control the No. 2 Diesel Product
flow rate by controlling FV-16237 on the No. 2 Diesel Product line.
FIC-16237 is linked to LIC-16182 in the DCS. LIC-16182 is the Fractionator,
T-1601 level controller and will open FV-16237 if the level in T-1601 rises
and will close FV-16237 if the level falls. There is a ¾-inch bleed valve
with a local mounted PI-16238 to indicate pressure on the No. 2 Diesel
Product line. There is 6-inch block valve with a ¾-inch bleed valve, then
the piping reduces to 4 inches at FV-16237. FV-16237 controls the No. 2
Diesel Product flow rate which controls the level in T-1601 as mentioned
above. Downstream of FV-16237, the piping increases to 6 inches and there is
a 6-inch block valve and a ¾-inch bleed valve. Downstream of the 6-inch
block valve downstream of FV-16237, the piping changes to ANSI 150-lb. class
flanges. There is a 4-inch bypass around FV-16237 with a 4-inch globe valve.
There is also a ¾-inch bypass around FV-16237 with ¾-inch block valves on
each end of the bypass and a ¾-inch bleed valve on each end. In the middle
of this bypass is a ¼-inch needle bleed valve. On the 6-inch No. 2 Diesel
Product line there is a 1½-inch connection for and TE-16240 that sends
signals to TIC-16240 in the DCS to indicate the temperature of the No. 2
Diesel Product after final cooling. TIC-16240 will give a High Temperature
alarm in the DCS if the temperature rises above a predetermined set point.
TIC-16240 is linked to the Speed Controller, SC-16253 that controls the
speed on the variable speed cooling fan on E-1608. On the line is a 4-inch
connection with a normally closed 4-inch block valve. This line is insulated
and electrically heat traced. It has a ¾-inch bleed valve downstream of the
4-inch block valve and the line is used for recycling the No. 2 Diesel for
startup purposes. On the startup line there is FE-16001 and FT-16001 that
send signals to for indication in the DCS of the No. 2 Diesel Product
recycle flow rate. sends a signal to FY-16001 to control the No. 2 Diesel
Product recycle flow rate by controlling FV-16001 on the No. 2 Diesel
Product recycle line. The 4-inch line has a 4-inch block valve and a ¾-inch
bleed valve upstream of a 4-inch by 2-inch reducer at the FV-16001.
Downstream of FV-16001, the line increases back to 4 inches. There is a
3-inch bypass with a 3-inch globe valve outside the block valves on
FV-16001. There is a 4-inch check valve and a ¾-inch bleed valve where the
4-inch line ties into the upstream of the Feed Filter, F-1601A, F-1601B.
Back on the 6-inch No. 2 Diesel Product line there is a
6-inch block valve located next to the previously mentioned 4-inch No. 2
Diesel Product recycle block valve. The 6-inch No. 2 Diesel Product line
splits and there is a 4-inch connection that is available to route to reject
if needed. This line has a 4-inch check valve, a ¾-inch bleed valve, a
blinding station, and a 4-inch block valve at the battery limits. The 6-inch
No. 2 Diesel Product line splits and is routed to storage through two 6-inch
connections each having a 6-inch block valve with a blinding station
upstream and a ¾-inch bleed valve on either side. These 6-inch valves are at
the battery limits.
On the second route of flow from the Fractionator
Bottoms Pump, P-1607A, P-1607B is an 8-inch connection, which is routed to
the No. 1 Diesel Stripper Reboiler, E-1606. During the winter mode of
operation, the Side Stripper, T-1602 is in operation and the Fractionator
Bottoms is routed through the tube side of E-1606. During the summer
operation when E-1606 is idled, the flow is bypassed around E-1606. The
8-inch Fractionator Bottoms piping has FE-16297 and FT-16297 that sends a
signal to FIC-16297 for indication in the DCS of the Fractionator Bottoms
flow rate eventually returning to T-1601. FIC-16297 sends a signal to
FY-16297 to control the Fractionator Bottoms flow rate by controlling
FV-16297 on the Fractionator Bottoms line to the Fractionator Reboiler,
H-1602. A 6-inch connection with a 6-inch gate valve then reduces to 4
inches with a ¾-inch bleed valve upstream of FV-16297. After FV-16297, the
piping increases back to 6 inches where there is a 6-inch gate valve and a
4-inch bypass with a 4-inch globe valve outside the block valves on
FV-16297. This flow bypasses E-1606 and ties into the outlet piping from the
tube side of E-1606. It is used during the summer operation mode. Downstream
of the connection for FV-16297, the 8-inch Fractionator Bottoms piping
reduces to 4 inches where there is a FE-16298 and FT-16298 that sends a
signal to FIC-16298 for indication in the DCS of the Fractionator Bottoms
flow rate to the tube side of E-1606. FIC-16298 is linked to TC-16200, on
E-1606 outlet piping. FIC-16298 sends a signal to FY-16298 to control
FV-16298, which controls the Fractionator Bottoms flow through the tube side
of E-1606. This controls the temperature on E-1606. As TC-16200 senses
E-1606 outlet temperature fall, it sends a signal for FV-16298 to open more
and as it senses E-1606 outlet temperature rise, it sends a signal for
FV-16298 to close. There is a 4-inch block valve, a 4 -nch by 2-inch reducer
and ¾-inch bleed valve upstream of FV-16298. The line increases back to 4
inches and there is a 4-inch block valve downstream of FV-16298. There is a
2-inch bypass line outside the block valves with a 2-inch globe valve on the
bypass line. The Fractionator Bottoms enters the 4-inch channel inlet nozzle
on the top of E-1606 where it exchanges heat with the Side Stripper, T-1602
Bottoms, which is circulating through the shell side of the
exchanger.
No.
1 Diesel Stripper Reboiler E-1606
No. 1 Diesel Stripper Reboiler
E-1606
The No. 1 Diesel Stripper Reboiler, E-1606 channel head
is designed for 300 psig at 650 °F and full vacuum at 350 °F. The channel
head inlet nozzle has a 1-inch blind-flanged connection and a 1½-inch
connection that has TW-16299 installed in it. There is a ¾-inch plugged
connection on the top and bottom of the channel head. The reboiler bundle
has 54 “U tubes” and is 12 feet long. The tube bundle is a 4-pass “U tube”
design. The channel head has internal pass partitions that direct the flow
through the first pass where the “U tubes” return the flow through the
second pass back into the channel head. From there, it is directed into the
third pass. The “U tubes” return the Fractionator Bottoms through the fourth
pass back to the channel where it flows out the 4-inch outlet nozzle. The
channel head outlet nozzle has a 1-inch blind-flanged connection and a
1½-inch connection that has TW-16300 installed in it. The 4-inch outlet
piping increases to 8 inches and joins the 8-inch piping downstream of
FV-16297. Downstream of this intersection there is a 1½-inch connection with
and TE-16292 that sends signals to TI-16292 in the . This indicates the
temperature of the Fractionator Bottoms to the Fractionator Reboiler,
H-1602. The 8-inch piping then splits into two 6-inch streams feeding
H-1602. One 6-inch line has FE-16171 and FT-16171 that sends signals to
FI-16171 for indication in the DCS of the Fractionator Bottoms flow to one
pass of E-1606. FI-16171 gives a Low Flow alarm when the flow drops below a
predetermined set point. Local mounted FI-16171A gives a local indication of
flow to E-1606. The other 6-inch line has FE-16172 and FT-16172 that sends a
signal to FI-16172 to indicate in the DCS the Fractionator Bottoms flow to
the other pass of E-1606. FI-16172 gives a Low Flow alarm when the flow
drops below a predetermined set point. Local mounted FI-16172A gives a local
indication of flow to E-1606. Each pass has a 6-inch globe valve for
manually controlling flow into E-1606. Both of the 6-inch lines reduce to 5
inches and enter the convection section of H-1602.
Fractionator Reboiler H-1602
Fractionator Reboiler H-1602
Downstream of the , the 3-inch piping splits and feeds
the 4 individual burners through 2-inch block valves, 2-inch ball valves,
and flex hoses.
The Fractionator Reboiler, H-1602 is a Fuel Gas fired
cylindrical furnace that has internal coils in the convection or flue gas
section and the radiant or firebox section for the transfer of heat to the
Fractionator Bottoms flowing through the furnace tubes or coils. The furnace
has four natural gas fired pilots and four Fuel Gas fired burners in the
bottom of the firebox. As the gas rushes in through the pilots and burners,
combustion air is drawn around them into the furnace where it mixes with the
gas and burns. The combustion process creates heated flue gases rich in
carbon monoxide. The flue gases give off radiant heat, which transfers
through the walls of the heater tubes in the firebox to the Fractionator
Bottoms flowing through the tubes. The heated flue gas rises through the
convection section of the furnace where it flows around the convection tubes
and transfers heat through the wall of the tubes to the Fractionator Bottoms
flowing through the tubes. The flue gas then continues to rise up and out of
the furnace stack creating a draft or negative pressure in the furnace. This
draft (called induced draft) pulls combustion air into the furnace. In the
stack is a stack dampener designed to allow adjustments to control the
amount of draft in the furnace. The stack dampener has a mechanical stop set
at approximately 10 – 15% minimum closure to prevent the accidental closing
of the damper, creating a potentially dangerous condition of positive
pressure in the firebox. There is a 3-inch connection on the stack below the
dampener for a stack gas analyzer. Stack gas analyzer local mounted O2
Analyzer Transmitter, AT-16175 sends a signal to board mounted O2 Analyzer
Indicator, AI-16175A for local indication of flue gas oxygen (O2) content
and O2 Analyzer Indicator, AI-16175 gives an indication of O2 content to the
. The local mounted Co Analyzer Transmitter, AT-16176 sends a signal to
board mounted Co Analyzer Indicator, AI-16176A for local indication of flue
gas carbon monoxide (CO) content and Co Analyzer Indicator, AI-16176
indicates the CO content to the DCS. The furnace has an additional
blind-flanged 3-inch connection below the stack dampener and two 4-inch
blind flanged connections above the stack dampener. The two 4-inch
connections are for EPA sample connections. The furnace has two 1½-inch
connections for furnace pressure taps. One is near the bottom and one is
below the convection coil. Both connections reduce to ¾-inches with ¾-inch
tubing running to ¾-inch plug valves. These tie together downstream of the
plug valves where there is a ½-inch plug bleed valve at PT-16291. PT-16291
sends a signal to local mounted PI-16291A for local indication of furnace
firebox pressure and sends a signal to PI-16291 in the DCS to indicate
furnace firebox pressure. The furnace has two 1½-inch connections that
reduce down to 1 inch for temperature indications. One is below the
convection coil and one above it. The lower connection has with TE-16167 and
TI-16167 to indicate temperature in the DCS. The upper connection has with
TE-16166 and TI-16166 to indicate temperature in the DCS.
Two 2-inch connections in the firebox are supplied by a
single 2-inch 150-lb. steam line with a 2-inch plug valve. The plug valve is
mounted at least 50 feet from the furnace so that it can be accessible in an
emergency situation. Upstream of the 2-inch plug valve on this line, is a
¾-inch connection with a ¾-inch bleed valve and steam trap with ¾-inch block
valves and a ¾-inch bleed valve around the trap. This ¾-inch line is routed
to the and is designed to keep the 150-lb. steam line hot and free of
liquid. The 150-lb. steam line is used for firebox purging or snuffing of
any firebox emergency event such as liquid in Fuel Gas, furnace tube
rupture, etc.
The pilot gas system consists of a 2-inch natural gas
supply to a 2-inch plug valve that is mounted at least 50 feet from the
furnace so that it can be accessible in an emergency situation. Downstream
of the plug valve is a ¾-inch bleed valve and a 1-inch bypass line with a
block valve that is car sealed closed. The 2-inch natural gas line reduces
to 1 inch and there is a 1-inch block valve, a Shutdown Valve, XV-16251A, a
¾-inch bleed valve, and a Shutdown Valve, XV-16251B. Between the shutdown
valves is a ¾-inch connection for Shutdown Valve, XV-16251C that vents to a
safe location. The signal to control the shutdown and vent valves is routed
through a 3-way Solenoid Valve, XY-16251. Downstream of the second Shutdown
Valve, XV-16251B is a 1-inch block valve and connection for the bypass
around the shutdown valves. Next, there is a ¾-inch bleed valve, a 1-inch
block valve, a Y strainer with a ½-inch bleed valve, a ¾-inch bleed valve
and PCV-16164, which controls the backpressure on the pilot gas to the
burners. Downstream of PCV-16164 is a 1-inch block valve. There is a 1-inch
bypass with a 1-inch globe valve around PCV-16164. Also downstream of
PCV-16164 is a ¾-inch connection for a local mounted PI-16252 for local
indication of the pilot gas pressure. On the same connection is PT-16165
that sends a signal to PI-16165 in the DCS to indicate the pilot gas
pressure. It also gives a Low Pressure alarm when the pressure falls below a
predetermined set point. A little further downstream, there is another
¾-inch connection with PT-16325 that sends a signal to the PI-16325 in the
DCS.
The pilot gas will be shutdown by PT-16325 in the DCS
when the pilot gas pressure drops below a predetermined set point. This will
trip Solenoid Valve, XY-16251, which will shut off the air signal to and
close Shutdown Valve, XV-16251A and Shutdown Valve, XV-16251B and open
Shutdown Valve, XV-16251C, which vents to a safe location. This shutdown can
also be initiated by activating the plant ESD HS-16023 or the heater ESD
HS-16174 located in the control room or by activating the heater ESD
HS-16173 located in the field. HS-16331 bypasses the pilot gas shutdown
system for startup. (Refer to the Cause and Effects Chart for more
information).
Downstream of the pilot gas control system, the 1-inch
piping splits and feeds the 4 individual pilots through ¾-inch block valves
and flex hoses. Each pilot has it own individual ignitor. sends a signal to
the , ; HS-16295 sends a signal to the Transformer, XY-16296A which in turn
activates Igniter, XY-16296B; sends a signal
to the , ; sends a signal to the , ; each controlling one ignitor.
The consists of an insulated 3-inch gas supply to a
3-inch plug valve that is mounted at least 50 feet from the furnace so that
it can be accessible in an emergency situation. Downstream of the plug valve
is a ¾-inch bleed valve and a ¾-inch bypass line with a block valve that is
car sealed closed. Downstream of the ¾-inch bleed valve is FE-16159 and
FT-16159 that send signals to FIC-16159 to indicate furnace Fuel Gas flow in
the DCS. FIC-16159 is linked to TIC-16170, which gets a signal from TE-16170
located on H-1602 outlet piping. TIC-16170 controls the Fuel Gas to H-1602
by sending a signal to FY-16159 that sends a signal to the Fuel Gas
FV-16159. The has a 3-inch block valve, Shutdown Valve, XV-16160A, ¾-inch
bleed valve and Shutdown Valve, XV-16160B. Between Shutdown Valve,
XV-16160A, XV-16160B is a ¾-inch bleed valve and a ¾-inch take off for
Shutdown Valve, XV-16160C that vents to a safe location. The signal to
control the shutdown and vent valves is routed through 3-way Solenoid Valve,
XY-16160. Downstream of the second Shutdown Valve, XV-16160B is a 3-inch
block valve and tie in for the bypass around the Shutdown Valve, XV-16160A,
XV-16160B, XV-16160C. Next, there is a 3-inch block valve, a ¾-inch bleed
valve, then the piping reduces to 1½ inch where FV-16159 controls Fuel Gas
flow to the burners. There is a 3-inch bypass line with a 3-inch globe valve
to bypass FV-16159. Downstream of FV-16159 the piping increases to 3 inches
and there is a 3-inch block valve. Downstream of the outlet block valve on
FV-16159 is a ¾-inch connection for a local mounted PI-16162 for local
indication of the Fuel Gas pressure. On the same connection is PT-16161
which sends a signal to PI-16161 in the DCS where it gives a read out of the
Fuel Gas pressure. No alarms shown on P & IDs???? A little further
downstream, there is another ¾-inch connection with PT-16163 that sends a
signal to PI-16163 in the DCS to indicate Fuel Gas pressure to H-1602 and
initiate a High High Fuel Gas pressure shutdown and Low Low Pressure
shutdown when the pressure rises above or falls below a predetermined set
point. This will trip Solenoid Valve, XY-16160, which will shut off the air
signal to and close Shutdown Valve, XV-16160A and Shutdown Valve, XV-16160B
and open Shutdown Valve, XV-16160C, which vents to a safe location. This
shutdown can also be initiated by activating the plant ESD HS-16023 or the
heater ESD HS-16174 located in the control room or by activating the heater
ESD HS-16173 located in the field. HS-16332 bypasses the Fuel Gas shutdown
system for startup. (Refer to the Cause and Effects Chart for more
information).
The Fractionator Bottoms flows into the tubes in the
convection section where it picks up heat from the hot convection gases
traveling up the furnace from the firebox out the stack. After flowing
through all the convection tubes, the Fractionator Bottoms exits the
convection section through 5-inch external crossover piping and then
increases to 6 inches and enters the tubes in the furnace radiant section.
While flowing through the radiant tubes, the Fractionator Bottoms picks up
the heat necessary for partial vaporization to flow up the Fractionator,
T-1601. It does this by absorbing radiant heat given off by the combustion
of Fuel Gas inside the firebox of the furnace. The heated Fractionator
Bottoms exits H-1602 in two 6-inch outlet lines. One 6-inch line has a
1½-inch connection with and TE-16168 that sends a signal to TI-16168 in the
DCS giving a readout of H-1602 pass outlet temperature. The other line has a
1½-inch connection with and TE-16169 that sends a signal to TI-16169 in the
DCS giving a readout of H-1602 pass outlet temperature. The two 6-inch lines
increase to 12 inches and combine into a single 12-inch pipe. On the 12-inch
outlet piping is a 1½-inch flanged connection with and TE-16170 that sends a
signal to TIC-16170 in the DCS to indicate the combined H-1602 outlet
temperature. TIC-16170 is linked to FIC-16159 to control the Fuel Gas to
H-1602 by sending a signal to the Fuel Gas FV-16159. TIC-16170 also gives a
High Temperature alarm in the DCS when the temperature rises above a
predetermined set point. There is a ¾-inch bleed valve on H-1602 outlet
piping and another ¾-inch bleed valve on the 12-inch piping prior to
entering T-1601 through a 12-inch connection below tray 35. The hot material
enters T-1602 where the hot vapors rise up and liquid falls to the
bottom.