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15 Cards in this Set
- Front
- Back
What does the Anhydrous Amonia tank use as a means to pressure up? |
Vaporizer Skid |
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What pressure does the Amonia tank normally run at? |
Approximately 55 - 75 psi. The vaporizers are used to heat and pressure up the tank. |
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What are the reliefs set at on the Anhydrous Amonia NH3 tank? On the liquid lines? Why are these different? |
Tank - 275 psi Line - 400 psi This is due to thermal expansion, there are reliefs on the liquid lines anywhere it can be isolated from the tank. |
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What special precautions must be taken when bleeding off sections of NH3 piping? |
NH3 should be bled into a bucket of water and not to atmosphere. |
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What is considered a high temperature downstream of the vaporizer heaters? When will the trip? |
Alarm 110° F Trip 114° F |
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What actions would you take on high pressure and/or temperature in the Anhydrous NH3 tank? |
Ensure the vaporizers are turning off. If temperature downstream of the heaters should shut off automatically at 114F if not shut off manually. This could be a sign of water in the vaporizers or tank and the temperature switch is malfunctioning. |
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What actions would you take on low pressure in the Anhydrous Amonia tank? |
Check vaporizers and breakers. Check regulators. |
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What pressure would be considered acceptable at the inlet on the SCR Skids? |
41-65 psi (typically regulated to 42 psi) |
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What is the temperature permissive for placing the Amonia injection in service? |
>500° F SCR inlet Gas temp |
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Explain the aux operators actions in the event of a total loss of the NH3 system? |
Work with the control room and see if there is anything that can be checked in the field. If the loss is due to a regulator failure then the regulators will need to be swapped using caution not to trip the excess flow valve. |
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What would cause the offload valve to go closed and not allow them to open? |
Amonia detector in alarm or tank high level. |
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When should an offload be stopped to avoid hitting the high level lockout? |
75% or 10,000 gallons because the lockout will trip at 10,200 and there needs to be room to blow the lines out. |
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Why should you open the valves slowly when swapping Anhydrous Amonia regulators? |
It could trip the excess flow valve causing a loss of flow of the Amonia system to the units. |
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At the NH3 storage tank and Amonia gas warning will initiate at ____ ppm and reset at ____ ppm. An alarm will initiate at ____ ppm and reset at ____ ppm. |
30/25 50/45 |
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Amonia = TWA ____ ppm, STEL ____ ppm. |
5/20 |