bobtail delivery operations module 6 injecting methanol and evacuating containers

BOBTAIL DELIVERY OPERATIONS

MODULE 6

Injecting Methanol and Evacuating Containers

LESSON 1


Introduction

In Propane Delivery Operations and Cylinder Delivery, you learned how to purge containers that have been exposed to air or moisture, or have not been vacuum purged by the manufacturer. This module contains procedures for safely injecting methanol into containers. Most stationary tanks are not designed to be moved once filled with liquid propane. However, in some cases, you may need to transport a tank from a customer location back to the plant for repair. As a result, it may be necessary to evacuate a stationary tank in the field.

Objectives

After completing this module, you will be able to:

Identify procedures for injecting methanol into containers Identify the features and functions of evacuation equipment Identify procedures for evacuating propane from an ASME tank using a portable

compressor Identify procedures for evacuating propane from an ASME tank using a bobtail

pump

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LESSON 1

Injecting Methanol Into Containers

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LESSON 1


Introduction

This lesson provides safety precautions for handling methanol and detailed procedures for injecting methanol into new containers which are not all alike.

Some marketers pre-treat new containers for moisture by adding a small quantity of methanol to them. Some container manufacturers have made this process easier by purging air from new containers and then sealing the container valves to create a vacuum condition inside the container.

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LESSON 1


Methanol Hazards

Although methanol looks just like water, it is a toxic substance and must be handled as a hazardous material.

Methanol is poisonous and should never come in contact with your skin, eyes, or mouth.

Methanol is highly flammable. Methanol fires are difficult to see. Methanol vapors in confined spaces have an

effect similar to ether. Breathing methanol that is soaked into clothing or spilled in the warm tightly closed cab of your vehicle can make you drowsy, or in high concentration render you unconscious.

Always wear appropriate personal protective equipment (PPE) when handling methanol, according to your company policy.

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LESSON 1


Preparing to Inject Methanol

Two different container conditions require the injection of methanol into propane containers:

Negative pressure: New containers that have been vacuum purged by the manufacturer have negative pressure.

Positive pressure: New containers that have not been vacuum purged by the manufacturer but have been purged with propane, have positive pressure. Containers already in service filled with propane also have positive pressure.

The procedures for injecting methanol under these two conditions are different. In this lesson, we will present these two different procedures.

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LESSON 1


Preparing to Inject Methanol into a Negative Pressure Container

Before injecting methanol into a container with negative pressure:

Gather the appropriate materials and equipment including the container of methanol and a short length of hose with male POL connector on one end.

Next, ensure the container’s pressure is negative by using the process recommended by the tank manufacturer. Do not add methanol unless the container pressure is negative.

Pull the bobtail’s liquid delivery hose to the receiving container and place it within arms reach of the service valve.

Check your company policy for the amount of methanol to be injected.

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LESSON 1


Preparing to Inject Methanol into a Negative Pressure Container cont.

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Gather the appropriate materials and equipment.

Ensure the container’s pressure is negative by using the process recommended by the tank manufacturer.

Pull the bobtail’s liquid delivery hose to the receiving container and place it within arms reach of the service valve.

LESSON 1


Steps for Injecting Methanol into a Negative Pressure Container

Once you are prepared to inject the methanol:

1. Attach the male POL adapter of the short hose to the service valve of the container and tighten.

2. Place the short hose into the methanol container to minimize air entering the tank during injection. Be sure the hose in the methanol container goes all the way to the bottom of the container and that the service valve on the tank is closed before the methanol level reaches the level of the hose opening.

3. Slowly open the service valve by turning it counter-clockwise and let the methanol flow into the tank.

4. Close the service valve as soon as the methanol is injected and disconnect the short hose. Check your company policy for the amount of methanol to be injected.

5. Attach the male POL adapter on the delivery hose-end valve to the service valve on the tank and tighten.

6. Slowly open the delivery hose-end valve, then open the service valve and let the tank pressurize.

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LESSON 1


Steps for Injecting Methanol into a Negative Pressure Container cont.

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Attach and tighten the male POL adapter of the short hose to the service valve of the container.

Place the short hose into the methanol container to minimize air entering the tank during injection.

Slowly open the delivery hose-end valve, then open the service valve and let the tank pressurize.

LESSON 1


After Injecting Methanol into a Negative Pressure Container

After injecting methanol into the container you should:

Close all valves once the container is pressurized.

Remove the manufacturer-applied shrink wrap plastic to indicate that the container is pressurized with LP-gas.

Properly stow and secure the hoses and the methanol container.

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LESSON 1


Preparing to Inject Methanol into a Positive Pressure Container

Before injecting methanol into the container:

Gather the appropriate materials and equipment including the container of methanol and the methanol injector.

Make sure that you have supplies available in case of a spill of methanol.

In existing service tanks, be sure to determine how much propane is in the tank so that the proper amount of methanol is added.

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LESSON 1


Steps for Injecting Methanol into a Positive Pressure Container

Once you are prepared to inject the methanol:

1. Attach the injection apparatus to the POL connection.

2. Check for leaks at the connection.

3. Follow the manufacturer’s recommendations on operating the methanol injector.

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LESSON 1


After Injecting Methanol into a Positive Pressure Container

After you inject methanol into the container:

Close the POL valve. Remove the injection apparatus following

manufacturer’s recommendations. Reconnect lines or cap POL fitting as required.

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LESSON 2

Evacuation Equipment

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LESSON 2


Introduction

If you need to transport an ASME tank from a customer location back to the plant for repair, you may need to evacuate the liquid propane from the tank before moving it.

According to U.S. DOT regulations, ASME containers with a capacity greater than 120 gallons are classified as bulk containers. ASME tanks filled to 5% of their capacity or less may be transported under certain conditions. ASME tanks with water capacities 126 to 500 G.W.C. filled to more than 5% may be transported one-way only from the consumer’s premises to the nearest bulk plant facility under certain conditions. For more information on the procedures for transporting an ASME tank, please review CETP Designing and Installing Exterior Vapor Distribution Systems. The propane evacuated from stationary tanks is normally transferred into the bobtail cargo tank. When a tank change out is done, an empty propane storage container of the same capacity is used.

This lesson introduces the different pieces of equipment you will use to evacuate propane from stationary tanks.

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LESSON 2


Portable Compressors

During the evacuation process, you may use either a portable compressor or your bobtail pump to transfer propane liquid from the customer’s tank to your cargo tank.

Portable compressors are usually belt-driven by an internal combustion engine and typically powered by propane vapor. Portable compressors are the more common and preferred method for evacuating propane from ASME tanks because they are more efficient and cause less wear and tear.

You should always use a portable compressor for evacuating if you are unable to position your bobtail close enough to the ASME tank. If a compressor is not available, you may need to move the ASME tank to a location that is closer to the bobtail. Do not use the tank’s lifting lugs when lifting an ASME tank with more than 5% liquid. Instead, use lifting slings with sufficient weight-bearing capacity ratings to cradle-lift the tank.

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LESSON 2


Bobtail Pumps

Using a bobtail pump is a less common method for evacuating propane. Some bobtail pumps are equipped with an auxiliary pump inlet that can also be used for evacuating propane in the field.

Whenever using your bobtail pump or auxiliary pump inlet to evacuate, be sure to position your vehicle so that the liquid transfer hose is as short as possible, but never longer than 50 ft.

The flow rate through the transfer hose is only 10-15 gallons per minute due to the limited flow capacity of the transfer and withdrawal valves. In comparison, the bobtail pump flow rate is 40-200 gallons per minute. With this large difference in flow rates, the bobtail pump can "starve" for liquid propane leading to pump damage. If the bobtail cannot be positioned any closer, use a portable compressor. A shorter hose also provides a faster flow of propane with less friction and resistance.

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LESSON 2


Liquid Transfer Hose

The liquid transfer hose connected between the stationary tank and the cargo tank must:

Be approved for LP- gas service. Be as short as possible and be at least ¾″ in

diameter. Have manual shutoff valves installed on both

ends. Contain a hydrostatic relief valve in the

liquid assembly. Contain appropriate fittings that will connect

the liquid supply line to the two tanks.

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LESSON 2


Vapor Hoses

With a Portable Compressor

You will use two vapor hoses if evacuating with a portable compressor: one connected between the cargo tank and the suction side of the compressor, and the other between the stationary tank and the discharge line of the compressor. If the stationary tank is not equipped with a vapor equalizing valve, install a purging adapter in the vapor service valve outlet before evacuating.

With a Bobtail Pump

You will use one vapor hose if evacuating with a bobtail pump connected between the stationary ASME tank and the cargo tank to balance the vapor pressure between the two tanks.

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Portable Compressor

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LESSON 2


Vapor Hoses cont.

During evacuation, occasionally check for vapor flow to ensure that the ASME tank’s excess flow feature in the vapor equalizing valve does not “slug” shut. One way to do this is to hold a section of the hose next to your ear and listen for flow. It may be necessary to momentarily close the vapor hose-end valve and then partially re-open it after the excess flow valve resets and opens.

Note: Check with your supervisor if your bobtail is not equipped with a vapor equalizing hose.

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Bobtail Pump

LESSON 2


Liquid Withdrawal Valves

ASME tanks built before the early 1960s have a combination filler valve and liquid withdrawal tube for evacuation. The liquid withdrawal tube is attached to the bottom of the filler valve and extends to the bottom of the container.

Newer ASME tanks have a separate evacuation valve called an actuated liquid withdrawal excess flow valve or simply, liquid withdrawal valve. This may be installed in the bottom, top, or side of the tank. An internal withdrawal tube extends to the bottom of the container and connects to the valve. During evacuation, this valve also serves as an excess flow valve.

Propane should never be vented into the atmosphere through these valves except as required during installation and removal of the transfer valve.

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LESSON 2


Liquid Withdrawal Valves cont.

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Pre 1960s Post 1960s

LESSON 2


Transfer Valves

Always install the appropriate transfer valve with a machined adapter into the liquid withdrawal valve before evacuating propane from the tank. When the transfer valve and adapter are screwed into the liquid withdrawal valve, the machined adapter forces the operator shaft down and moves the valve disc off of its seat.

Install a transfer valve with a ¾″ NPT inlet and 1¾″ ACME hose connector in the outlet. Use the machined adapter supplied by the liquid withdrawal valve manufacturer.

Remember, exposure to liquid propane when installing transfer valves can result in frostbite or freeze burns.

Note: Always where appropriate PPE and take special care with angle valves to ensure they point away from people.

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LESSON 2


Additional Equipment

The liquid propane in the stationary ASME tank can be removed through either a top or bottom opening. A special unloading adapter is needed to operate the filler valve.

Always read the manufacturer's instructions for each adapter.

An operating stem extends through the bottom of each of the unloading adapters. Rotating the lever (or hand wheel) moves the operator stem. When the adapter is installed on a filler valve, the moving operator stem pushes open the back checks in the filler valve so the liquid can be removed from the stationary ASME tank.

Some marketers insert a sight gauge that allows you to visually see the liquid propane moving through hose from the ASME tank to the bobtail.

Note: Any person using an unloading adapter to evacuate a container through a filler valve must have a thorough working knowledge of the liquid withdrawal adapter and its effect on the double back check feature of the filler valve. These adapters were not intended to be, nor should they be used as, a permanent means of dispensing liquid for any purpose.

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LESSON 2


Additional Equipment cont.

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Unloading Adaptor Sight Gauge


LESSON 3

Evacuation Procedures

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LESSON 3


Introduction

This lesson provides safety precautions and detailed procedures for using a portable compressor or a bobtail pump to evacuate propane from a stationary ASME tank. The procedures described in this lesson are based on the following assumptions:

Liquid will be evacuated from stationary ASME tanks with water capacities between 125 and 1,000 gallons.

Liquid will be withdrawn through a liquid withdrawal valve with a transfer valve installed.

The tank used to receive the liquid from the stationary tank being evacuated is a bobtail cargo tank.

Note: These procedures are based on common industry practice and provisions in NFPA 58. Check state, local, and company procedures for any additional guidelines, methods, or equipment requirements.

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LESSON 3


Evacuation Safety Precautions

During evacuation, it is important to remember that propane is a flammable gas and that exposure to liquid propane can result in frostbite or freeze burns. Use these precautions during evacuation.

Wear appropriate personal protection equipment (PPE) and use proper transfer procedures.

Be thoroughly familiar with ASME tank construction, valves, and all other evacuation equipment used.

Check that all hoses used in the evacuation procedure are designed and listed for use with liquid propane. They must be 1,750 psig bursting pressure, and 350 psig working pressure.

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LESSON 3


Evacuation Safety Precautions cont.

Remove sources of ignition from the point of transfer. Also, ensure that all internal combustion engines within 15 ft of the point of transfer are shut down during the transfer operation.

Keep at least one recently inspected fire extinguisher with a minimum capacity of 18 pounds dry chemical and B:C rating within reach during the entire operation.

Note: A qualified individual must be present during the entire evacuation procedure.

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LESSON 3


The Portable Compressor Method

Follow these steps to evacuate liquid propane using a portable compressor:

Step 1: Determine the amount propane to be transferred.

Step 2: Prepare the Evacuation Site Step 3: Connect and Inspect Pressurized

Hoses Step 4: Evacuate Liquid Propane Step 5: Bleed Down and Disconnect Hoses

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LESSON 3


Step 1: Determine Amount of Propane to Transfer

Before leaving the bulk plant, check to see that the liquid level in the bobtail cargo tank is low enough to handle the entire water capacity of the ASME tank to be evacuated.

These steps will prevent overfilling your cargo tank:

1. Read the percent volume indicated by the rotary or float gauge on the bobtail’s cargo tank.

2. Multiply the percent volume by the water capacity of the cargo tank. The resulting number is the current volume, in gallons, of propane in the bobtail’s cargo tank.

3. Add the water capacity of the stationary ASME tank to be evacuated to the volume of propane in the bobtail’s cargo tank.

The total amount must not be higher than the maximum permitted filling level for the cargo tank on the bobtail.

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LESSON 3


Step 1: Determine Amount of Propane to Transfer cont.

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LESSON 3


Step 2: Prepare the Evacuation Site

Position the bobtail and compressor: Place the compressor between the bobtail and the stationary tank being evacuated. The bobtail should be at least 10 ft from the suction side of the compressor. The maximum distance between the compressor and the two tanks will depend on the length of the vapor hose.

Carefully and slowly loosen the plug or cap from the liquid withdrawal valve: Be extremely cautious when loosening the cap. Take extreme care to loosen and remove just the plug or cap, not the entire withdrawal valve. Never loosen the plug or cap more than one turn.

If propane liquid stops escaping from the weep hole, it is safe to continue removing the plug or cap. Remember that there are different manufacturers of liquid withdrawal valves, so please follow their instructions as well as your company policy.

Lay out the liquid transfer hose between the stationary tank and the cargo tank: Ensure the fitting on the hose-end valve is protected from rocks, dirt, and other debris. Hoses should be capped when not in use.

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LESSON 3


Step 2: Prepare the Evacuation Site cont.

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Position the bobtail and compressor.

Connect the transfer valve to the inlet of the liquid withdrawal valve on the stationary tank.

Lay out the liquid transfer hose between the stationary tank and the cargo tank.

LESSON 3


Step 3: Connect and Inspect Pressurized Hoses

Connect the liquid transfer hose—Connect one end of the liquid transfer hose to the outlet of the transfer valve and the other end to the fill connection on the bobtail cargo tank.

Connect the vapor hoses—Connect one vapor hose between the discharge side of the compressor and the vapor equalizing valve (or purging adapter) on the stationary tank. Connect the second vapor hose between the suction side of the compressor and the vapor equalizing connection on the bobtail’s cargo tank.

Test the vapor and liquid hoses—Slowly open the transfer valve in the stationary tank to pressurize the liquid supply line. Then open each valve downstream and check all hoses for damage and connections for leaks. Close all valves in the line and make repairs if necessary.

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LESSON 3


Step 3: Connect and Inspect Pressurized Hoses cont.

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Connect the liquid transfer hose. Connect the vapor hoses. Test the vapor and liquid hoses for leaks.

LESSON 3


Step 4: Evacuate Liquid Propane

Turn on the portable compressor to begin evacuating propane. Portable compressors are run to create a pressure differential to move product between the two tanks. When running the portable compressor, be sure to monitor the pressure in the stationary ASME tank to avoid over-pressurization. For example, if the excess flow valve closes, stopping the flow of liquid during the procedure, the compressor must be shut down or excess pressure will build in the stationary tank.

Observe the liquid level gauges on the ASME tank and the cargo tank. As product transfers between the tanks, the liquid level gauge should be reducing on the ASME tank and increasing on the cargo tank. Be careful not to overfill the cargo tank. When the liquid level in the ASME tank reaches 5% or less, turn off the compressor and close all valves.

Note: Always read and follow manufacturer instructions before using a portable compressor.

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LESSON 3


Step 4: Evacuate Liquid Propane cont.

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Turn on the portable compressor. Observe the liquid level gauges on the ASME tank and the cargo tank.

LESSON 3


Step 5: Bleed Down and Disconnect Hoses

During this step, any liquid propane trapped in the hose connections is bled off to the atmosphere at the customer location.

Disconnect the liquid transfer hose—Bleed down and disconnect the liquid transfer hose connections at the transfer valve and at the bobtail fill connection.

Close the excess flow valve—Quickly open the transfer valve and allow propane to flow through until the excess flow check valve “slugs” shut. If the excess flow valve fails to close, the shutoff valve must be fully closed and must NOT be removed until the system is evacuated and the unit repaired.

Remove the liquid withdrawal and transfer valves from the ASME tank—Ensure you have the plug/cap and Teflon washer readily available for the liquid withdrawal valve. Remove the liquid withdrawal valve and transfer valve from the ASME tank. Reinstall the plug/cap and Teflon washer into the liquid withdrawal valve.

Disconnect the vapor hose—Bleed down and disconnect the vapor hose from the ASME tank either at the vapor equalizing valve or the purging adapter. Remove the purging adapter from the vapor service valve, if applicable. Install any dust caps on the hoses or stationary valves. Bleed down and disconnect the vapor hose from the bobtail cargo tank. Bleeding down liquid and vapor hoses on a customer site is very serious business—be careful. Install any dust caps on the hose or the vapor connection on the cargo tank.

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LESSON 3


Step 5: Bleed Down and Disconnect Hoses cont.

Disconnect from the compressor—Bleed down and disconnect the suction and discharge hose fittings from the compressor.

Disconnect the fill connection hose—Disconnect the hose from the fill connection on the cargo tank, if applicable.

Store all equipment—Store all tools, supplies, hoses, and transfer equipment.

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Bleed down and disconnect the liquid transfer hose connections.

Bleed down and disconnect the vapor hose from the ASME tank.

Store all tools, supplies, hoses, and transfer equipment.

LESSON 3


The Bobtail Pump Method

Follow these steps to evacuate liquid propane using a bobtail pump or an auxiliary pump inlet.

Step 1: Determine the Amount of Propane to Transfer

Step 2: Prepare the Evacuation Site Step 3: Connect and Inspect Pressurized

Hoses Step 4: Evacuate Liquid Propane Step 5: Bleed Down and Disconnect Hoses

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LESSON 3


Step 1: Determine the Amount of Propane to Transfer

Before leaving the bulk plant, check to see that the liquid level in the bobtail cargo tank is low enough to handle the entire water capacity of the ASME tank to be evacuated.

These steps will prevent overfilling your cargo tank:

1. Read the percent volume indicated by the rotary or float gauge on the bobtail’s cargo tank.

2. Multiply the percent volume by the water capacity of the cargo tank. The resulting number is the current volume, in gallons, of propane in the bobtail’s cargo tank.

3. Add the water capacity of the stationary ASME tank to be evacuated to the volume of propane in the bobtail’s cargo tank.

The total amount must not be higher than the maximum permitted filling level for the cargo tank on the bobtail.

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LESSON 3


Step 1: Determine the Amount of Propane to Transfer cont.

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LESSON 3


Step 2: Prepare the Evacuation Site

Position your bobtail—Position your bobtail as close as permitted to the stationary ASME tank being evacuated, usually 10 to 50 ft away, depending on the length of the liquid delivery hose. Position the bobtail parallel to the stationary ASME tank if the auxiliary pump inlet is on the side of the vehicle. Back the bobtail toward the side of the ASME tank if the auxiliary pump inlet is at the rear of the vehicle.

Lay out the liquid transfer hose between the stationary tank and the cargo tank.

Inspect the hose-end fitting—Ensure the fitting on the hose-end valve is protected from rocks, dirt, and other debris. Hoses should be capped when not in use.

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LESSON 3


Step 3: Connect and Inspect Pressurized Hoses

Connect liquid transfer hose—Connect one end of the liquid transfer hose to the outlet on the unloading adapter or the transfer valve on the stationary tank. Connect the other end to the auxiliary pump inlet on the bobtail.

Connect delivery hose—Connect the end of the delivery hose to the fill connection on the bobtail.

Connect vapor hoses—Connect the vapor equalizing hose between the vapor equalizing connection on the bobtail cargo tank and the vapor equalizing valve (or purging adapter) on the stationary tank.

Test the vapor and liquid hoses—Slowly open one valve at a time, starting with the transfer valve in the stationary tank, to test the liquid supply line. Check all connections downstream to the next closed valve for leakage once a valve is opened. Slowly open each valve downstream one at a time after each section of line is considered tight. Close all valves in the line and make repairs, if any leaks are detected.

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LESSON 3


Step 4: Evacuate Liquid Propane

Open all shutoff valves—Ensure that all shutoff valves are open in the liquid transfer hose, the vapor equalizing hose, and the truck delivery hose. Ensure that all valves are open between the auxiliary pump inlet and the delivery hose. Ensure that the liquid internal valve is closed.

Start the engine and engage the cargo tank pump—The pump should operate at the slowest possible speed. Over-speeding will only increase wear on the pump.

Observe the liquid level gauges on the ASME tank and the cargo tank—Stop the pump immediately when there is no indication of liquid transfer, the transfer pump becomes noisy or suddenly increases in speed, or when the ASME tank liquid level gauge reads at least 5% or less.

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LESSON 3


Step 4: Evacuate Liquid Propane cont.

Check the float gauge—Check the float gauge in the ASME tank to be sure that most of the propane has been removed. The excess flow valve in the evacuation valve could have slugged if the gauge does not indicate a decrease in container propane volume. Allow the excess flow valve to reset and restart the pump if this is the case. Monitor the flow with the sight gauge. When the liquid level in the ASME tank reaches 5% or less, shut down the pump.

Close all valves—Close all valves in the liquid transfer hose, including the transfer valve and any shutoff valve between the pump-off inlet and the delivery hose. Close all valves in the bobtail/CTMV delivery hose assembly and at the fill connection of the cargo tank. Close all valves in the vapor equalizing hose. Close the vapor service valve in the stationary ASME tank with the purging adapter attached, if applicable.

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LESSON 3


Step 5: Bleed Down and Disconnect Hoses

During this step, liquid propane trapped in the hose connections is bled off to the atmosphere at the customer location.

Disconnect the liquid transfer hose—Bleed down and disconnect the fitting of the liquid transfer hose connected to the closed transfer valve. Bleed down and disconnect the liquid transfer hose connection at the bobtail pump-off adapter or fill connection. Bleeding down liquid and vapor hoses on a customer site is very serious business—be careful.

Close the excess flow valve—Carefully and quickly open the transfer valve and allow liquid propane gas to flow through until the excess flow check valve “slugs” shut. If the excess flow valve fails to close, the shutoff valve must be fully closed and must NOT be removed until the system is evacuated and the unit is repaired.

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LESSON 3


Step 5: Bleed Down and Disconnect Hoses cont.

Remove the transfer valve from the ASME tank—Before removing the liquid withdrawal valve and transfer valve, have the liquid withdrawal valve plug/cap and Teflon washer readily available for installation. Then, while it is still connected to the liquid withdrawal valve, remove the transfer valve from the ASME tank after the excess flow valve has been “slugged.” Reinstall the plug/cap and Teflon washer into the liquid withdrawal valve.

Disconnect the vapor hose—Bleed down and disconnect the vapor hose fitting from the stationary ASME tank, either at the vapor equalizing valve or the purging adapter. Remove the purging adapter from the vapor service valve, if applicable. Install any dust caps on the hoses or stationary valves. Bleed down and disconnect the vapor hose fitting from the bobtail’s cargo tank. Install any dust caps on the hose or the vapor connection on the cargo tank. Disconnect the hose from the fill connection on the cargo tank.

Store all equipment—Store all tools, supplies, hoses, and transfer equipment.

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LESSON 3


Summary

Some important points to remember from this module are:

There may be times when you are required to add methanol to vacuum purged ASME tanks in the field. Remember, methanol is highly toxic so always wear appropriate PPE and use caution.

Evacuating ASME tanks is one of the most dangerous tasks you will perform as a bobtail driver. Pay close attention to the hazards associated with this process and always wear appropriate PPE, especially when installing transfer valves and liquid withdrawal valves.

The most common and preferred method used for evacuation is the portable compressor because it’s more efficient and causes less wear and tear.

When running a portable compressor, be sure to monitor the pressure in the stationary tank to avoid over-pressurization.

When using a bobtail pump, stop the pump immediately when there is no indication of liquid transfer, if the transfer pump becomes noisy or suddenly increases in speed, or when the ASME tank liquid has been lowered to the 5% level or less.

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bobtail delivery operations module 6 injecting methanol and evacuating containers

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