VERSENE Chelating Agents

Bulk Unloading and Loading

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Description
Unloading
Unloading Control Logic
Recycle Tank
Downloads
Tank Control Logic
Loading
Loading Control Logic


Bulk Unloading and Loading VERSENE Chelating Agents – Description and Control Logic

The following information is intended to provide a brief summary of transfer, loading and unloading operations. The user should ensure that their own operations are conducted safely and in compliance with all national and local requirements.

Description

Unloading and loading operations are possible out of tank cars or tank trucks using an open dome system. Take care while performing these operations to prevent damage to equipment.

Unloading

After a tank car or tank truck has been received and properly secured, proceed as follows:
  1. Open the bleed valve at the top of the tank car or tank truck.
  2. Open the dome.
  3. Connect a flex hose with a 1/2 inch receiving line purge valve to the unloading pump.
  4. Line up the manual valves from the tank car or tank truck to the storage tank. Close all the bleeds.
  5. Turn on the unloading pump.
  6. After unloading is complete, turn off the pump.
  7. Connect regulated air or nitrogen purge (not more than 20 psig) to the 1/2 inch receiving line and purge for 5 minutes.
  8. Turn off the purge and close all the manual valves in unloading lineup.
  9. Disconnect the flex hose.
  10. Close the dome on the tank car or tank truck.

Unloading Control Logic

Two level-sensing instruments are used to protect against overfilling the storage tank; one is a primary and the other is a backup, included in case the primary fails.

When either of these is activated, prevent wiring from energizing the unloading pump and keep the unloading valve closed.

During normal operations if the tank approaches being overfilled, the unloading valve will close and the unloading pump will shut off, securing the unloading operation. An alarm activated by the level-sensing instruments will notify the unloader of the overfilled state.

Recycle Tank

Prior to unloading or filtering the tank may be mixed to get a representative sample. Take the following steps:

  1. Close the line to the loading station and all bleeds.
  2. Open the manual valves in the recycle lineup.
  3. Turn on the pump and allow the tank to recycle.
  4. The inline process filter should be protected with a safety relief valve to prevent filter over-pressure.
  5. Filters need changing if the pressure difference gets high across the filters, an indication of plugging. A range of 15 to 20 psi drop may be used as a starting point. This will vary with pumping rates and piping. Experience will dictate filter changes.
  6. A 10-micron cartridge filter may be used for this application. When changing filters, always isolate the filter pot and bleed internal pressure. Failure to do this can result in personal injury.
  7. The tank can be set up for top or bottom recycle. If a bottom recycle is chosen, use a tank mixing eductor for better results.
  8. To secure recycling operations, turn off the transfer pump and close the manual valves in the line.

Downloads

Typical Bulk Handling System for VERSENE* Chelating Agents (20KB PDF).

Notes

  1. Recycle can be bottom entry by using tank mixing eductor typ. Fig 268-B Schutte & Koerting Co.
  2. Piping materials are typically 304 SS.
  3. Tank vent should be sized for adequate tank protection.
  4. Low amp pump shutdowns may be adapted to prevent dry pump operation.
  5. Tank linings: Amercoat 74 or 75, Chem-Pon 231OR, DERAKANE*, Plasite 7122, Sigma Phenguard, Phenoline 37.
  6. If tank is lined, lapweld inside seams.
  7. Valves: gate, ball or plug, SS with seams.
  8. Tank inlet/discharge 12" off bottom.

Tank Control Logic

The storage tank should be equipped with a float type tank level indicator. It should be equipped with a high/low level alarm to inform personnel of tank conditions.

Loading

After tank car or tank truck has been prepared for loading and secured, proceed as follows:

  1. Open the bleed valve at the top of the tank car or tank truck.
  2. Open the dome and move the loading line in place.
  3. Place the level-sensing instrument in the dome of the tank car or tank truck.
  4. Set the flow element to the desired transfer.
  5. Close all bleed valves in the loading lineup.
  6. Open all manual valves in the loading lineup.
  7. Turn on the transfer valve and begin transfer.
  8. Monitor loading conditions and filter pressure during the transfer.
  9. The transfer valve will close when the counter on the flow element is complete. This should be used as a secondary indicator and control. Primary responsibility rests with the loading operator to monitor and insure the quantity of transfer.
  10. The level sensing equipment in the tank car or tank truck is a backup system that will only alarm on high-level conditions.
  11. When transfer is complete, shut off the transfer pump and close the manual valves to the loading station.
  12. Remove the loading line and close the dome on the tank car or tank truck.

Loading Control Logic

The loading operations are monitored by use of a turbine meter or equivalent type flow meter equipped with a preset counter and shutoff output. The preset is used for setting the transfer quantity. The shutoff output should be wired to close the transfer valve to stop the transfer. An alarm should notify the loading operator that transfer is complete. A level-sensing instrument installed in the tank car or tank truck dome will monitor the level and alarm when overfilling conditions exist, either due to error or failure of the flow element preset counter or automatic shutoff.

Primary responsibility should rest with the loading operator to monitor this operation.


®™* Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow