3.7.5 CETP Instructor PowerPoint Template

Transcript 3.7.5 CETP Instructor PowerPoint Template

3.7.5

Identifying Procedures for Evacuating DOT Intermodal (IM) Tank at Bulk Plants

A full understanding of the operation of the liquid evacuation process if essential to the removal of the liquid from propane containers safely.

In this module you will learn to identify: 1.

Hazards and safety precautions associated with evacuating propane liquid Proper equipment for evacuating the DOT IM tank Procedures for evacuating propane form a DOT IM tank 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 1

Identifying Hazards and Safety Precautions Associated with Evacuating Propane Liquid

• Because DOT Intermodal tanks, used for LP-gas services, must conform to DOT 51 specifications, it is permissible to transport the IM tank while filled with propane. It is therefore likely that evacuation of a DOT IM will be done at the bulk plant site. In most instances such evacuation will be done in preparation for repairing or replacing tank valves or fittings or to perform other maintenance operations 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 1

Identifying Hazards and Safety Precautions Associated with Evacuating Propane Liquid

• Exposure to liquid propane can result in freezing of the skin • Exposure to flammable gas and other materials at high pressure • Potential ignition of flammable gas • All sources of ignition within 25 feet of the point of transfer must be removed, extinguished, or turned off for the duration of the operation. Internal combustion engines within 15 feet (5m) of the point of transfer must be shut down while transfer operations are in progress, except for engines on transfer equipment and others as listed in NFPA 58 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 1 & 2

Identifying the Proper Equipment for Evacuating the IM tank

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Plant Pump or Compressor Liquid Transfer Hose

• It should be listed and approved for liquid propane gas service (350 psig operating pressure, 1750 psig bursting pressure). • The length should be as short as possible and at least 3/4" (preferably 1") in diameter • Manual shutoff valves such as snap-action globe valves, hand wheel-operated globe valves, or ball valves should be installed on both ends of the hose Figure 1. Liquid Transfer Hose 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 2 & 3

Identifying the Proper Equipment for Evacuating the IM tank

• • •

Liquid Transfer Hose

A hydrostatic relief valve should be installed in the liquid assembly. The relief valve prevents the hose from bursting due to liquid expansion when liquid propane gas is trapped between the two shut-off valves.

Fittings must be selected that will connect the liquid supply line to the two tanks. The inlet to the liquid supply line (stationary tank) will be connected to the transfer valve (installed in the withdrawal valve). The outlet of the liquid supply line will be connected to either the pump-off adapter or directly to the fill connection on the plant storage tank (when a compressor is used).

All threaded connections in the liquid line should be sealed with thread sealing compound (except POL and ACME threads).

Identifying the Proper Equipment for Evacuating the IM tank

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Vapor Hoses

– If the tank is not equipped with a vapor-equalizing valve, install a purging adapter (Figure 2) in the vapor service valve outlet.

Identifying the Proper Equipment for Evacuating the IM tank

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Additional Adapters or Valves

Figure 3a. Sherwood 902A Figure 3b.

Identifying the Proper Equipment for Evacuating the IM tank

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Actuated Liquid Withdrawal Excess Flow Valves

• If a significant amount of liquid continues to be blown from under the closing cap for more than 30 seconds, it can be assumed that the internal seat will not prevent a dangerous amount of gas from escaping. IF IN DOUBT, DO NOT REMOVE THE CLOSING CAP. Should only vapor be leaking from under the cap, the connection to the liquid withdrawal valve can usually be made Figure 4. Actuated Liquid Withdrawal Excess Flow (Evacuation) Valve Figure 5. Transfer Valve with Machined Adapter 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 5 & 6

Identifying the Proper Equipment for Evacuating the IM tank WARNING

Exposure of body tissues to liquid propane when installing transfer and withdrawal valves can result in frostbite or freeze burn. Protect your hands and other body parts with appropriate PPE.

Special care is required with angle valves to ensure that they do not direct liquid toward people or ignition sources.

Identifying the Proper Equipment for Evacuating the IM tank

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Commonly Used Withdrawal Valve Installations

• • •

Rego Chek-Lok 7572FC/7580FC and the Chek-Loc 7590U/7591U Sherwood Checkmate 5133S or 5135S Fisher SafEvac F171 and F210 WARNING

Read and strictly follow manufacturer instructions for the installation, use and removal of evacuation transfer valves.

Observe all warnings and precautions.

If you do not have experience evacuating containers, ask your supervisor for assistance.

Identifying Procedures for Evacuating Propane from a DOT IM Tank

Information outlining features of liquid withdrawal valves, unloading adapters and installation methods is given in the Supplemental Information section of this module. Always read and follow manufacturers’ instructions for use. Use the adapters specified by manufacturers and wear personal protective equipment while evacuating propane containers.

Remember at all times that you are working with a pressurized flammable gas

. Follow all company-specific procedures that apply.

Identifying Procedures for Evacuating Propane from a DOT IM Tank

• Regardless of the equipment used, since evacuation requires the transfer of both propane liquid and vapor, all procedures and safety precautions should be fully understood and applied. Note the procedures described below are limited to the following tanks and equipment: – DOT IM tanks with water capacities between 250 gallons 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 tank being evacuated is a bulk plant storage tank, or other appropriate tank .

– A bulk plant pump or compressor will be used to evacuate the liquid in the IM tank .

Identifying Procedures for Evacuating Propane from a DOT IM Tank

• • • •

Determine the Quantity of Propane to be Transferred

: Read the percent volume indicated by the rotary or float gauge on the plant storage tank .

Multiply the percent volume indicated by the water capacity of the storage tank. The resulting number is the current volume, in gallons, of propane in the cargo tank .

Add the water capacity of the DOT IM tank to be evacuated to the volume of propane in the plant storage tank .

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

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 1: Step 2:

Uncap and connect one end of the transfer hose to the outlet on the unloading adapter or the transfer valve on the IM tank. Connect the other end to the plant storage tank system. Connect vapor-equalizing hoses between the equalizing connection on the plant storage tank and the vapor-equalizing valve (or purging adapter on the IM tank).

•Ensure that all shut off valves are open in the liquid transfer and vapor equalizing hoses •Ensure that all valves are open between the pump off inlet and delivery hose. The internal self-cleaning stop valve should be closed 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 8

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 3: Step 4: Step 5:

Start Pump . Stop the pump immediately when there is no indication of liquid transfer. Check the float gauge in the IM tank to be sure that most of the liquid propane gas has been removed. The excess-flow valve in the evacuation valve could have slugged if the gauge indicates more than 5%. Allow the excess-flow valve to reset and restart the pump if this is the case. Monitor the flow with the sight gauge.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 6: Step 7: Step 8:

When liquid has been lowered to the lowest level possible, shut down the pump. Close all valves in the liquid transfer hose, including the transfer valve and any shut-off valve between the pump-off inlet and the delivery hose.

Close all valves in the IM delivery hose assembly and at the fill connection of the storage tank. Close all valves in the vapor equalizing hose. Close the vapor service valve in the IM tank (with purging adapter attached), if applicable.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 9:

Bleed Down and Disconnect all Hoses. During this procedure, liquid propane gas trapped in the hose connections is bled off to the atmosphere. Any liquid propane gas trapped in the hose itself (between shut-off valves) must be bled off at the customer location. The steps for bleeding down the transfer hose are as follows.

•Bleed down and disconnect the fitting of the liquid transfer hose connected to the closed transfer valve, and the storage tank.

•Fully open the transfer valve and allow liquid propane gas to flow through until the excess-flow check valve "slugs" shut.

CAUTION:

If the excess-flow valve does not "slug" shut, immediately close the transfer valve. Do not remove the transfer valve until the pressure in the tank has been reduced to 0 psig. Once the pressure has been reduced, the withdrawal valve must be serviced before the IM tank is returned to service.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 9:

•Remove the transfer valve, Teflon washer, and adapter from the IM tank after the excess flow valve has been "slugged.“ •Reinstall the plug and Teflon washer into the liquid withdrawal valve.

CAUTION:

Do not cross thread the plug during installation. Also, avoid tightening or moving the withdrawal valve when installing the plug.

•Disconnect the vapor hose fitting from the IM tank (either at the vapor-equalizing valve or the purging adapter).

•Remove the purging adapter from the vapor service valve, if applicable.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Pump Transfer Method Step 9:

•Bleed down and disconnect the vapor hose fitting from the plant storage tank. Install any dust caps on the hose or the vapor connection on the bulk propane storage tank.

•Bleed down and disconnect the bulk plant hose form the fill connection on the plant storage tank.

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

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method: Step 1:

Connect a transfer valve to the inlet of the withdrawal valve on the IM tank •Begin by screwing a machined unloading adapter into the inlet of the transfer valve.

•When removing the plug or cap from the liquid withdrawal valve, be sure only the plug is loosened and removed.

•While removing the plug, if an excessive volume of propane leaks from the valve, reinstall the plug and follow manufacturer’s instructions.

•Install the transfer valve according to manufacturer’s instructions.

•Once installed, close the transfer valve.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 2:

Close all valves in the liquid transfer line

Step 3: Step 4:

Lay out the liquid transfer hose between the stationary tank and the cargo tank •Ensure the liquid transfer hose-end valve is protected from foreign matter (rock, dirt, etc.) •Hoses should be capped when not in use. Connect on end of the liquid transfer hose to the outlet of the transfer valve and the other end to the fill connection located on the plant storage tank.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 5:

Connect the vapor hoses between the compressor and tanks. Connect the discharge hose between the discharge side of the compressor and the vapor equalizing valve (or purging adapter) on the IM tank.

•Connect the suction hose between the suction side of the compressor and the equalizing connection on the plant storage tank .

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 6:

Pressure Test the Vapor and Liquid Hoses. Slowly open one valve at a time, starting with the transfer valve in the stationary tank, to pressure tests 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 3.7.5 Student Book  © 2004 Propane Education & Research Council Page 11

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 7:

Transfer as much liquid as possible form the IM propane tank to the storage tank. Read and follow compressor manufacturer instructions. Typically, portable compressors are run only for short time periods of one or two minutes to create a pressure differential between the two tanks.

•Ensure that all external sources of ignition are at least 25 feet from any part of the transfer area before beginning the transfer operation. Also, ensure that all internal combustion engines within 15 feet of the point of transfer are shut down during the transfer operation, with exceptions as listed in NFPA 58 which includes an exception for internal combustion engines that power the transfer equipment .

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 8:

Bleed Down and Disconnection all Hoses. During this procedure, liquid propane gas trapped in the hose connections is bled off to the atmosphere. Any liquid propane gas trapped in the hose itself (between shut-off valves) must be bled off. The steps for bleeding down the transfer hose are as follows.

•Bleed down and disconnect the fitting of the liquid transfer hose connected to the closed transfer valve.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 8:

•Fully open the transfer valve and allow liquid propane gas to flow through until the excess flow check valve “slugs” shut

CAUTION:

•Remove the transfer valve, Teflon washer, and adapter from the IM tank after the excess flow valve has been “slugged.” •Reinstall the plug and Teflon washer into the liquid withdrawal valve.

CAUTION:

Do not cross thread the plug during installation. Also, avoid tightening or moving the withdrawal valve when installing the plug.

Identifying Procedures for Evacuating Propane from a DOT IM Tank Using the Plant Compressor Transfer Method Step 8:

•Bleed down and disconnect the vapor hose fitting from the IM 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 storage tank. Install any dust caps on the hose or the vapor connection.

•Bleed down and disconnect the suction and discharge hose fittings from the compressor, if applicable. •Disconnect the hose from the fill connection on the bulk plant storage tank.

Time to See If You Got the Key Points of This Module…

3.7.5 CETP Instructor PowerPoint Template

Transcript 3.7.5 CETP Instructor PowerPoint Template

Time to See If You Got the Key Points of This Module…

• Complete the Review on page 14 & 15.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 16.

3.7.5 CETP Instructor PowerPoint Template

Transcript 3.7.5 CETP Instructor PowerPoint Template

Time to See If You Got the Key Points of This Module…

• Complete the Review on page 14 & 15.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 16.

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