YungPlantEng
Chemical
- Jan 19, 2022
- 82
We have around 20 pumps that are relatively small in size (3600 RPM / 1800 RPM 6-12" impellers) that are used to pump bisulfite fertilizer and soda ash slurries. These currently use a single-pass flush of soft water that is pre-heated to 100 F via direct steam contact PRIOR to entering the seal. A 1 GPM variable orifice flowmeter is used to provide this single-pass flush, and the seal return goes to our neutralization system.
Senior technicians are positive the seals will salt up on the atmospheric side if we don't use hot soft water or at the very least a single-pass flush. They had bypassed the original air-pressurized seal pots existing on these systems years ago and I would like to make use of them. I have the following questions:
1. Is there an actual phenomenon related to solute fall-out in the case of cold water (60 F) contacting a slightly higher temperature stream (70F - 120F)? I can understand sulfides crusting over on the seal over time but this seems more related to the original pressures the pots ran at than anything else.
2. When using variable flowrate orifices in a single-pass flush would I be able to reduce these orifice flowrates to less than 1 GPM? Best practices seems to recommend 1 GPM as an absolute minimum but it sounds like we're already breaking all the rules using these and pre-heating the water....
3. Would anyone have experience with upstream pump rings (JC)? I was planning to modify the existing air-pressurized seal pots that aren't in use and modify the mechanical seals - there is not a massive concern about losing a couple gallons a day to product but in the event of a seal failure an unpressurized system doesn't sound very safe.
Thanks for any input on this guys.
Senior technicians are positive the seals will salt up on the atmospheric side if we don't use hot soft water or at the very least a single-pass flush. They had bypassed the original air-pressurized seal pots existing on these systems years ago and I would like to make use of them. I have the following questions:
1. Is there an actual phenomenon related to solute fall-out in the case of cold water (60 F) contacting a slightly higher temperature stream (70F - 120F)? I can understand sulfides crusting over on the seal over time but this seems more related to the original pressures the pots ran at than anything else.
2. When using variable flowrate orifices in a single-pass flush would I be able to reduce these orifice flowrates to less than 1 GPM? Best practices seems to recommend 1 GPM as an absolute minimum but it sounds like we're already breaking all the rules using these and pre-heating the water....
3. Would anyone have experience with upstream pump rings (JC)? I was planning to modify the existing air-pressurized seal pots that aren't in use and modify the mechanical seals - there is not a massive concern about losing a couple gallons a day to product but in the event of a seal failure an unpressurized system doesn't sound very safe.
Thanks for any input on this guys.
