API Plan 53B

API Piping Plan 53B FSA Knowledge Series

DISCLAIMER While the FSA makes every reasonable attempt to ensure that the information contained in this document is accurate and current, the FSA, its officers, directors, volunteers, and authorized agents are not responsible for any errors or omissions contained therein nor are they responsible for any results obtained from the use of or reliance upon its content. All information is provided “AS IS,” with no guarantee of completeness, accuracy, timeliness or of the results obtained, and without warranty of any kind, express or implied. In no event shall FSA or its officers, directors, volunteers, or authorized agents be liable to you or anyone else for any decision made or action taken in reliance on the information con tained herein or for any for any consequential, indirect, special, or similar damages, even if advised of the possibility of such damages. The informa tion contained in this document is for informational purposes only and does not constitute professional advice. It also includes references to certa in standards that may change over time and should be interpreted only in light of particular circumstances. It is your sole responsibility to confi rm the current state of any referred to standards. FSA reserves the right to modify or update the document content and to modify this Disclaimer at any t ime, effective upon posting of an updated version of this Disclaimer. © August 2025, Fluid Sealing Association. All Rights Reserved.

Abstract This Fluid Sealing Association Knowledge Series training presentation introduces API Piping Plan 53B. A description is provided on: ▪ What is an API Plan 53B? ▪ How an API Plan 53B Works ▪ What does an API Plan 53B do?

▪ What an API Plan 53B cannot do ▪ Optional Features for an API Plan 53B ▪ Cost to Operate With An API Plan 53B ▪ How to Size an API Plan 53B ▪ How to Install an API Plan 53B ▪ General API Plan 53B Commissioning Guidelines ▪ How to Operate an API Plan 53B ▪ General Troubleshooting of an API Plan 53B ▪ Alternatives to an API Plan 53B 3

What Are Piping Plans?

4

▪

Piping plans collectively are different piping arrangements of fluid used to improve the conditions the mechanical seal operates in with the objective of improving the mechanical seal’s life.

▪

The American Petroleum Institute adopted numbers and created definitions for each piping plan configuration, thereby allowing a common language across the industry to simply describe a particular configuration.

▪

The American Petroleum Institute standard API-682 is where the definition of each piping plan can be found and where they may periodically be updated.

What is an API Plan 53B? An API Plan 53B is one of a series of piping plans that provide a pressurized liquid barrier fluid to a dual liquid lubricated mechanical seal.

An API Plan 53B provides: ▪

Zero emissions of the pumped fluid to the environment

▪

A method to pressurize the barrier fluid

▪

A reservoir of barrier fluid to replace fluid consumed by the mechanicals seal

▪

A heat exchanger to dissipate heat generated by the mechanical seal and absorbed from the pump

▪

Instrumentation to monitor seal performance and detect early onset of seal performance deterioration

▪

Containment of pumped fluid in the event of seal or support system failure

5

What is an API Plan 53B? API Plan 53B consists of the following components: Gas Bladder Pre-charge Port Barrier Fluid Refill High Point Vent Mechanical Seal

Optional Temperature Transmitter Bladder Accumulator

Pressure Transmitter

6

Heat Exchanger

Drain

How an API Plan 53B Works Dual liquid lubricated mechanical seals contain a pumping device within the mechanical seal that circulates barrier fluid in a cooling circulation loop, through a heat exchanger, returning to the mechanical seal. An API Plan 53B is used to pressurize the fluid in this cooling circulation loop and provide a reservoir of fluid to replace fluid consumed by the mechanical seal through normal leakage.

Pressurized Gas Stored Barrier Fluid 7

Circulating Loop Mechanical Seal

Bladder Accumulator Heat Exchanger

How an API Plan 53B Works To move the barrier fluid through the circulating loop, a pumping ring can be incorporated into the mechanical seal design. There are various styles and shapes of pumping rings, however they are all driven by the rotating shaft of the equipment.

Radial flow pumping ring

With higher shaft speeds, the pressure and flow generated by the pumping ring will increase.

Axial flow pumping ring Barrier fluid Process fluid

8

Atmosphere side

How an API Plan 53B Works Gas Port Pressure is generated in an API Plan 53B with a bladder accumulator containing a gas pressurized rubber bladder.

Pressure Vessel

A bladder accumulator consists of a metallic pressure vessel with a gas port at one end, and a liquid port at Gas Volume the other. Connected to the gas port is a rubber Rubber Bladder bladder that is pressurized internally via a valve connected to the gas port.

Liquid Volume

The liquid port communicates with the space between the outside of the rubber bladder and the inside of the pressure vessel. A spring-loaded poppet valve is placed in the liquid port to prevent the rubber bladder from extruding into the liquid port when it is pressurized.

9

Poppet Valve Liquid Port

How an API Plan 53B Works As a liquid, a barrier fluid is incompressible. When pumped into the bladder accumulator liquid port, the incompressible liquid will compress the gas in the gas bladder there by pressurizing the liquid. As more liquid is introduced into the bladder accumulator liquid port, gas in the bladder is further compressed, increasing the pressure of liquid.

The relationship between the size of the bladder accumulator, gas bladder pre-charge pressure, and liquid in the accumulator can be described with the combined gas laws. As the combined gas laws also consider temperature, changes in ambient temperature can also affect the pressure of the gas inside of the bladder.

10

How an API Plan 53B Works Combined gas law: 𝑃1 · 𝑉1 𝑃2 · 𝑉2 = 𝑇1 𝑇2 Where: P = Pressure (in absolute pressure units of measure) T = Temperature (absolute temperature - Kelvin or Rankin) V = Volume of gas in the accumulator gas bladder Subscript 1 represents the conditions when the gas bladder was pre-charged.

Subscript 2 represents the conditions being evaluated.

Note: liquid volume = total accumulator volume less gas volume

11

How an API Plan 53B Works

Pressure

With addition of liquid barrier fluid into the accumulator, the gas bladder is compressed and pressure increases

Pressure

Stored liquid volume

Gas Liquid

12

Stored liquid volume

Pressure

How an API Plan 53B Works

Pressure

Stored liquid volume

13

Stored liquid volume

With increasing temperature, liquid volume remains constant, however gas pressure increases resulting in a corresponding increase in liquid pressure.

How an API Plan 53B Works During operation of a liquid dual pressurized mechanical seal, barrier fluid is consumed as a result of normal leakage. Stored liquid volume in the bladder accumulator will exit the accumulator into the cooling loop to replace the lost fluid.

This will result in a decrease of the pressure of the barrier fluid as the gas bladder expands to replace the lost fluid.

When the liquid volume in the accumulator reaches a minimum, an alarm is triggered for the operator to refill the accumulator with fresh barrier fluid.

The refill alarm can be simply based on a minimum pressure to represent an approximate volume of liquid remaining (ignoring temperature effects) or a combination of pressure and gas bladder temperature to determine a more precise volume of liquid remaining.

14

What does an API Plan 53B do?

15

▪

Provides a source of pressurized barrier fluid without the need for external utilities (e.g. live pressure source)

▪

The rubber bladder separates the barrier fluid from the pressurized gas eliminating pressurized gas dissolving into the barrier fluid

▪ ▪

Can be used for high pressure applications (no gas solubility issues) Allows the selection of a wide variety of heat exchangers that can accommodate higher heat loads

▪

Has a small footprint – the bladder accumulator does not need to be immediately adjacent to the cooling loop

▪

Barrier pressure will change with stored liquid volume and ambient temperature

▪

The only flow within the accumulator is to replace fluid lost by normal consumption (leakage) by the mechanical seal and to refill the accumulator

What an API Plan 53B cannot do An API Plan 53B cannot:

16

▪

Guarantee any pumped fluid will not reach the environment

▪

Predict when a mechanical seal will fail

▪

Provide a visible liquid level of barrier fluid

▪

Provide a constant barrier pressure

▪

Provide a simple and easy sizing and selection process without support from your mechanical seal vendor

▪

Provide continuous operation without periodic refilling of the accumulator

▪

Operate for extended periods of time in a failure mode

▪

Provide an extended barrier fluid life when compared to alternative pressurized systems due to higher thermal cycling of the barrier fluid

▪

Be used with a single seal

Optional Features for an API Plan 53B Valve and Instrumentation Options: ▪

Gas bladder temperature transmitters – allows calculation of remaining liquid volume in the accumulator

▪

Isolation valve and pressure gauge to allow isolation and draining of the accumulator to check gas bladder integrity and pre-charge pressure

TIT

Temperature Transmitter

PI

Pressure Gauge

PIT

17

Isolation Valve

Optional Features for an API Plan 53B Valve and Instrumentation options: ▪

Pressure relief valve to prevent over pressurization of the barrier fluid

▪

Temperature measurement – Addition of thermowells and local temperature indicators to measure barrier fluid temperature in and out of the mechanical seal

Pressure Relief Valve

PIT TI

Typical temperature indicator and thermowell 18

TI

Temperature Indicators

Optional Features for an API Plan 53B Accumulator Temperature Control Options: Controlling the accumulator temperature to minimize changes from ambient temperature variations and solar radiation can be achieved with:

19

▪

Insulation of the accumulator for hot and cold climates

▪

Heat tracing the accumulator for cold climates

▪

Sunshades when installations are exposed to the sun

▪

Light colored paint to provide low surface emissivity

Accumulator Sunshade

Instrumentation Sunshade

Optional Features for an API Plan 53B Barrier fluid circulation: Internal to the mechanical seal ▪

Radial flow pumping ring

▪

Axial flow pumping ring

Radial flow pumping ring 20

Axial flow pumping ring

Optional Features for an API Plan 53B Heat Exchanger style: API Plan 53B allows the selection of a variety of different style heat exchangers.

Shell and tube heat exchanger

Tube-in-tube heat exchanger Natural convection heat exchanger 21

Forced convection heat exchanger

Optional Features for an API Plan 53B Accumulator Design Features ▪ Pressure vessel code and certification ▪ ▪ ▪ ▪ ▪ ▪

▪

Materials of construction ▪ ▪

22

ASTM (American Society for Testing and Materials) PED (Pressure Equipment Directive) GOST (Gosudarstvennyy Standard) UL (Underwriters Laboratory) CR (Canadian Registration) Region-specific design regulations Rubber bladder material choices for barrier fluid compatibility Pressure vessel material choices for barrier fluid compatibility and/or environment compatibility

Optional Features for an API Plan 53B Barrier Fluid Refilling Options Portable ▪ Portable wheeled cart with reservoir and pump Wheeled Cart with Hand (hand or pneumatic) Pump ▪ Local reservoir with pump (hand or pneumatic) ▪ Central reservoir with pump refilling multiple API Plan 53B accumulators ▪ Reservoir with automated refill control system (digital or pneumatically actuated)

Local Reservoir with Pneumatic Pump 23

Cost to Operate With an API Plan 53B Cost of barrier fluid Barrier fluid is consumed during the normal operation of the mechanical seal.

Consumption rate will vary with mechanical seal design, shaft speed, pressure, and barrier fluid.

Cost of utilities A method to remove heat absorbed into the barrier fluid requires utilities either in the form of cooling water (for a water-cooled heat exchanger) or electricity (for a forced convection heat exchanger). Natural convection heat exchangers do not require any utilities.

Cost of energy balance Heat is removed from the process via the API plan 53B system. This energy needs to be replaced within the pumping system and there is an associated cost for the energy to achieve this.

24

Cost to Operate With an API Plan 53B Friction losses The operation of a dual mechanical seal results in friction being generated by the seal faces.

This friction creates a drag on the rotation of the shaft which the drive needs to overcome.

There is a cost for the energy needed to overcome this frictional drag

Labor costs An API plan 53B system requires routine maintenance to: 1) Monitor the performance of the API Plan 53B system and mechanical seal 2) Periodically replenish the consumed barrier fluid

25

Cost to Operate With an API Plan 53B Typically, the initial investment for an API plan 53B system is high, however the ongoing operational costs are low after the system is installed.

▪

Energy to operate

▪

Carbon footprint

▪ ▪

$

$$$$

Initial investment

$

$$$$

Cost of operation

$

$$$$

Refer to the Fluid Sealing Association’s Lifecycle Cost Calculator (LCC) for a more detailed analysis.

26

How to Size an API Plan 53B Working Principle The pressure generated by the accumulator is determined by the initial pressure (precharge) of the gas-charged rubber bladder. As barrier fluid is pumped into the accumulator, the pressure increases from the initial pre-charge pressure. Any temperature changes to the gas stored in the accumulator caused by variations in ambient temperatures can cause changes in the pressure. The pressure at any point can be described by the combined gas law: 𝑃1 · 𝑉1 𝑃2 · 𝑉2 = 𝑇1 𝑇2

Where: P = Pressure (in absolute pressure units of measure) T = Temperature (absolute temperature - Kelvin or Rankin) V = Volume of gas in the accumulator gas bladder 27

How to Size an API Plan 53B When graphed, the relationship between stored fluid volume, pressure, and ambient temperature can be shown.

Example: Summer:

40°C (104°F)

Winter:

10°C (50°F)

40°C (104°F)

Pre-charge: 20°C (68°F) 20°C (68°F) 10°C (50°F)

28

How to Size an API Plan 53B Alarm Set Points Alarms are established to notify the operator that actions is required. There are two critical set points: Refill Alarm This alarm notifies the operator to add barrier fluid to the accumulator

Full Set Point This alarm notifies the operator to stop adding barrier fluid to the accumulator

There are two different alarm strategies where these set points are based on a fixed pressure or based on a floating pressure (fixed fluid volume) in the accumulator.

29

How to Size an API Plan 53B Fixed Pressure Alarm Strategy This method measures pressure only and offers a much simpler approach to alarm the barrier system. This method can use either a pressure switch or transmitter. However, as pressure also varies with temperature, the remaining fluid volume in the accumulator is not directly linked to the accumulator pressure.

Advantages ▪ ▪ ▪ ▪

Simple to instrument Lower initial cost Simple to operate Local readout of accumulator pressure available

Disadvantages ▪ ▪ ▪ 30

Reduced working volume with low ambient temperatures Larger accumulator needed Higher differential pressure between full and empty

How to Size an API Plan 53B Floating Pressure Alarm Strategy This method uses the ability to create an algorithm within the end user’s data acquisition system to correlate stored barrier fluid volume with accumulator pressure and temperature. This method requires monitoring of the barrier pressure and gas temperature in the accumulator gas bladder using transmitters. The algorithm computes the remaining barrier fluid volume with the input of temperature and pressure and compares this volume to the alarm set points.

Advantages ▪ ▪

Allows a smaller effective working volume and hence small accumulator size Reduces the pressure differential between the accumulator full and empty

Disadvantages

31

▪ ▪ ▪

Complex instrumentation and higher initial cost required No local readout of fluid volume remaining Requires an algorithm to be programmed into the data acquisition system

How to Size an API Plan 53B The hydraulic accumulator stores barrier fluid that is consumed by the normal operation of the mechanical seal. In addition, a safety volume is also retained within the accumulator to provide a safety cushion between barrier fluid refill intervals.

The volume of barrier fluid consumed by the mechanical seal over a predefined period of time, typically one month, is the working volume. Your mechanical seal vendor can assist performing the API Plan 53B sizing calculations.

The safety volume is typically up to 10% of the working volume.

The total stored fluid volume in the accumulator is the combination of the safety and working volume. This volume will deplete over time as the barrier fluid is consumed by the mechanical seal.

32

How to Size an API Plan 53B Accumulator size The total stored fluid volume is typically 15 to 25% of the internal volume of the accumulator. Common accumulator sizes are: 20 L (5 US Gallon) 35 L (9 US Gallon) 50 L (13 US Gallon)

Example:

33

Seal leakage: 10 ml/hr (0.34 fl. oz./hr) Refill interval period: 28 days Working volume: 6.72 L (1.78 US Gallons) Safety volume: 0.67 L (0.18 US Gallons) Total liquid volume: 7.39 L (1.95 US Gallons) Accumulator size: 35 L (9 US Gallon) Liquid volume: 21.1 %

How to Size an API Plan 53B Pre-charge Pressure The internal bladder of the accumulator is pre-charged with nitrogen gas. The precharge pressure of the gas bladder is selected to achieve a pressure differential above the maximum seal chamber pressure with the safety volume stored in the accumulator.

The combined gas laws are used to calculate the pre-charge pressure knowing the minimum barrier pressure and safety volume.

This pressure is adjusted based on the ambient temperature at the time the gas bladder is pressurized, and this temperature must be recorded.

34

How to Size an API Plan 53B Accumulator volume: 35 L (9 US Gallon) Pre-charge Pressure Example

Pressure-Volume relationship at maximum temperature (35°C (95°F))

Pressure-Volume relationship at 20°C (68°F)

ressure olume Rela onship

Maximum seal chamber pressure: 15 Barg (218 psig)

Minimum barrier pressure differential: Minimum barrier pressure with safety volume at maximum temperature: 16.4 Barg (238 psig)

Safety Volume: 0.67 L (0.18 US Gallons)

Minimum barrier pressure differential Maximum seal chamber pressure

Accumulator pre-charge pressure at 20°C (68°F): Accumulator pre-charge 14.3 Barg (207 psig) 35

ressure

arg

1.4 Bar (20 psi)

pressure at ambient temperature (20°C (68°F))

i uid olume Remaining in the Accumulator

Safety Volume

Pressure-Volume relationship at minimum temperature (0°C (32°F))

How to Size an API Plan 53B - Continued Pressure-Volume relationship at maximum temperature (35°C (95°F))

Fixed refill alarm strategy Once the pre-charge pressure at ambient conditions has been established, the liquid full set point can be established. arg

Full set point pressure

16.4 Barg (238 psig)

Working volume:

Refill Alarm Pressure

ressure

Refill Alarm:

ressure olume Rela onship

6.72 L (1.78 US Gallons)

Full set point pressure: 25.1 Barg (364 psig) i uid olume Remaining in the Accumulator

Pressure-Volume relationship at minimum temperature (0°C (32°F)) 36

Working Volume

How to Size an API Plan 53B

ressure olume Rela onship

arg

Once the safety volume and working volume have been established, an algorithm can be created that will convert Full set point volume temperature and pressure measurements recorded by the Refill Alarm transmitters and convert these Volume inputs into the volume of liquid remaining in the accumulator.

Alarms can be established based on liquid volume remaining.

Pressure-Volume relationship at minimum temperature (0°C (32°F))

Pressure-Volume relationship at maximum temperature (35°C (95°F))

ressure

Floating pressure alarm strategy

i uid olume Remaining in the Accumulator

Working Volume 37

How to Size an API Plan 53B Barrier fluid circulation The barrier fluid flow produced by the mechanical seal pumping ring (or external pump) needs to be sufficient to enable transfer of the heat absorbed into the barrier fluid (a combination of energy from seal heat generation and heat soak from the equipment) to the heat exchanger.

Seal Face Heat Generation

Barrier Fluid Circulation

Seal Heat Soak from Equipment 38

Natural Convection Heat Loss

Heat Dissipated by Heat Exchanger

How to Size an API Plan 53B An insufficient flow rate will result in large differential temperatures between the barrier fluid in and out connections at the mechanical seal and an increase in the overall temperature of the barrier fluid.

Excessive barrier fluid temperatures result in a number of problems affecting the performance and reliability of the mechanical seal.

Mechanical seals with internal pumping devices (pumping rings) have a strong correlation to shaft speed. Flow can dramatically reduce when shaft speeds are low and may require the use of an external circulation pump.

39

How to Size an API Plan 53B Heat Exchanger One of the main advantages of an API Plan 53B is the flexibility offered in the choice of heat exchanger style and capacity. With the absence of physical restrictions of traditional API Plan 53A systems, larger cooling capacity heat exchangers can be selected.

When matching the heat exchanger cooling capacity to the heat load placed on the barrier fluid, consideration needs to be made to the effect of increases in the resistance to barrier fluid flow commonly associated with larger heat exchangers.

Undersized heat exchangers will result in excessive barrier fluid temperature which creates a rapid decrease in mechanical seal reliability.

40

How to Install an API Plan 53B Heat Exchanger location The position of the heat exchanger relative to the mechanical seal is important. It should be located as close as possible and a short distance above the mechanical seal centerline (without obscuring access for pump maintenance activities).

Accumulator location The accumulator can be mounted a substantial distance away from the barrier fluid circulating loop without any impact to the system’s performance. However, many installations will mount the heat exchanger and accumulator together on the same stand.

41

How to Install an API Plan 53B Interconnection pipe/tubing Tube or piping connecting the mechanical seal to the heat exchanger should be selected to produce minimal resistance to barrier flow. Large diameter bores, smooth radius bends, short distances, minimal ancillary equipment added into the circulating loop all help lower the resistance to barrier fluid flow.

High point vents must be installed to allow removal of air from the system during commissioning. Lines should slop upwards to the vent point with a minimum slope of mm per meter .5” per foot

Low point drains should be provided to remove barrier fluid when decommissioning the equipment.

42

How to Install an API Plan 53B Alarm Set Points With your alarm strategy determined, set the alarm set points to the predetermined values for each instrument.

Refill/Precharge Accumulator

For Item No.: xxx For It em

Alarm Setting

Temperature

min.

normal

max.

Caution: Caution:

Gauge Pressure Precharge Refill Alarm °C °F MPa (bar) (psi) MPa (bar) (psi) MPa (bar) (psi) -17 1 2.61 26.1 378 3.25 32.5 472 2.63 26.3 382 -15 5 2.63 26.3 381 3.28 32.8 476 2.65 26.5 385 -10 14 2.68 26.8 389 3.34 33.4 485 2.71 27.1 393 -5 23 2.73 27.3 396 3.41 34.1 495 2.76 27.6 400 0 32 2.79 27.9 404 3.47 34.7 504 2.81 28.1 408 5 41 2.83 28.3 411 3.54 35.4 513 2.86 28.6 415 10 50 2.88 28.8 418 3.60 36.0 522 2.92 29.2 423 15 59 2.94 29.4 426 3.67 36.7 532 2.96 29.6 430 20 68 2.99 29.9 433 3.73 37.3 541 3.02 30.2 438 25 77 3.03 30.3 440 3.79 37.9 550 3.07 30.7 445 30 86 3.09 30.9 448 3.85 38.5 559 3.12 31.2 453 35 95 3.14 31.4 455 3.92 39.2 568 3.17 31.7 460 40 104 3.19 31.9 463 3.99 39.9 578 3.22 32.2 467 45 113 3.24 32.4 470 4.05 40.5 587 3.28 32.8 475 50 122 3.30 33.0 478 4.11 41.1 596 3.32 33.2 482 55 131 3.34 33.4 485 4.17 41.7 605 3.38 33.8 490 60 140 3.39 33.9 492 4.24 42.4 615 3.43 34.3 497 65 149 3.45 34.5 500 4.30 43.0 624 3.48 34.8 505 70 158 3.50 35.0 507 4.36 43.6 633 3.53 35.3 512 Do not adjust gas precharge pressure with liquid barrier fluid or pressure in the auxiliary piping system.

Do not add barrier liquid to exceed maximum refill pressure @ temperature

Typical API Plan 53B Nameplate 43

xxx

No.:

How to Install an API Plan 53B Ambient weather conditions Installations where large variation in ambient temperatures occur, a shade hood or insulation should be fitted to the accumulator and consideration to changing the accumulator’s color to white or silver should be reviewed.

Excessive temperature variations can impact the maximum barrier pressure, minimum barrier pressure margin above the seal chamber pressure and reduce the effective barrier fluid working volume when the refill alarm is activated.

For extreme cold environments, insulation and heating can be provided for the accumulator, interconnecting piping, and instrumentation.

44

General API Plan 53B Commissioning Guidelines Commissioning must occur with the pump depressurized!

Gas Bladder Commissioning In most installations, the hydraulic accumulator is received with the gas bladder factory pre-charged with nitrogen to the selected pre-charge pressure. If the gas bladder needs to be charged, follow the manufacturers procedures to charge the bladder.

45

General API Plan 53B Commissioning Guidelines Filling the Accumulator Typically, the accumulator is filled from a portable cart fitted with a liquid reservoir and pump. The pump is often a hand pump or a pneumatically driven piston pump. Use clean, fresh barrier fluid to fill the accumulator.

When first filling the accumulator, the pressure will rise rapidly until sufficient pressure is available to lift the poppet valve that is being pushed closed by the pressure in the gas bladder. Once the poppet valve has lifted, liquid will flow into the space between the accumulator shell and gas bladder, where the added liquid will start to squeeze the gas bladder.

Continue adding barrier fluid until the Full set point pressure has been reached.

46

General API Plan 53B Commissioning Guidelines Venting the System Using the high point vent valve(s) installed in the interconnecting piping, vent the air trapped in the piping. As air is vented, barrier fluid will flow into the interconnected piping and pressure will drop.

This will require multiple cycles of refilling the accumulator and venting the high point vents to completely remove any air from the system.

When possible, the shaft should be rotated by hand to assist purging the mechanical seal barrier cavity of air.

Bleed all instrument block and bleed valves.

Continue the refill and vent cycles until you get a solid stream of liquid with no bubbles flowing from the vent valves.

47

General API Plan 53B Commissioning Guidelines Alarm Set Point Verification During the fill and vent cycles, the changes in pressure can be used to confirm the alarm set points and to validate communication between the instrument, the data acquisition system, and the local readout.

Leak Checks Check all connections and fitting for visible leakage. Tighten any fittings if leakage is found.

48

General API Plan 53B Commissioning Guidelines Heat Exchanger Commissioning Depending on the style of heat exchanger in use, any required utilities, such as cooling water or electrical fan, should be activated and verified that cooling water or air is flowing.

External Barrier Fluid Circulating Pump When present, any external barrier fluid circulating pump should be switched on to start barrier fluid circulation.

49

General API Plan 53B Commissioning Guidelines Pump Commissioning The pump is now ready to be flooded and the equipment operators standard commissioning procedures followed.

50

How to Operate an API Plan 53B Periodic Barrier Fluid Refilling Barrier fluid is consumed during the normal operation of the mechanical seal.

This will require periodic replenishment of barrier fluid into the accumulator to make up for the fluid consumed. Barrier fluid is added to the accumulator until the Full set point pressure has been reached.

The barrier fluid consumption rate is a strong indicator of the health of the mechanical seal. A decrease in the refill interval is an early warning of declining mechanical seal performance.

51

How to Operate an API Plan 53B Periodic Inspection of Utilities Periodic measurement of the barrier fluid temperature into and out of the heat exchanger should be performed to monitor heat exchange efficiency.

An increase in the differential temperature across the heat exchanger inlet and outlet is an indication of a decrease in efficiency that can be caused by insufficient cooling flow or fouling of the heat exchanger heat transfer surfaces.

52

How to Operate an API Plan 53B Gas Bladder Pre-charge Pressure Verification The gas bladder pre-charge pressure can only be verified when the pump has been decommissioned and the barrier fluid has been depressurized and drained from the system.

The best opportunity to complete this inspection is during a pump overhaul when the pump has been removed from service. The local temperature as well as the measured gas bladder pressure will be needed to determine if there has been any loss of the pre-charge pressure.

Pre-charge pressure verification can be helpful when diagnosing mechanical seal performance issues.

53

General Troubleshooting of an API Plan 53B Symptom

54

Potential causes

▪

Decreasing refill interval

Increasing mechanical seal leakage Leaking fittings

▪

Elevated temperature

Insufficient barrier fluid circulation Heat exchanger fouling Insufficient heat exchanger cooling flow Undersized heat exchanger Inadequate venting Change in process pressure or temperature

General Troubleshooting of an API Plan 53B Symptom

55

Potential causes

▪

Rapid decrease in pressure

Major mechanical seal failure Poppet valve closed and isolated the accumulator Delayed maintenance refilling of the accumulator Gas bladder rupture

▪

Changes in pressure between day and night

This is normal resulting from ambient temperatures cooling overnight

Alternatives to an API Plan 53B Alternative piping plans that are similar:

DPIT

LI LT

API Plan 53A Gas pressurized vessel

56

API Plan 53C Piston accumulator pressurized system

Alternatives to an API Plan 53B Alternative piping plans that are similar:

PIT

API Plan 54 Fluid from an external system

57

FIT

API Plan 74 Dual pressurized non-contacting gas seal

API Plan 53B Summary API Plan 53B pressurized seal systems offer a safe and reliable solution for a wide range of applications exceeding the scope of traditional API Plan 53A systems.

The minimal utility requirements and installation flexibility offer significant advantages over other dual seal systems.

The correct sizing of the accumulator, the heat exchanger and the barrier fluid flow rate together with best installation & operational practices and effective alarm strategy are the keys to years of reliable performance from an API Plan 53B system.

58

THANKS!

www.fluidsealing.com

59