JoeChem
Chemical
- Dec 9, 2002
- 50
Greetings,
Working on a prelimiary design for a new processing facility - reactor followed by 3 distillation columns. Need to develop a sized equipment list for approximate total installed costs.
The columns are to be operated under vacuum conditions and working on sizing vacuum pumps for the application. The systems are totally condensed and vapor pressures in the reflux drum are low so at this point looking for an air leakage estimate to get a decent idea of required pump capacity.
Have little else to go on at this point so attempting to use the air leakage curves published by the Heat Exchange Institute as a starting point but the resulting leakage numbers seem very low. For one situation we have a column with an estimated internal volume of ~ 350 ft3 to be operated at 50 mmHg. Based on the system volume and operating pressure the HEI curves predicts the leakage rate at ~ 7 lb/hr or about 31 ACFM. Comparing to vacuum pump specs on P&ID's from other processes thinking this capacity should be an order of magnitude higher. Realize safety factors should be applied but the ACFM result just seems way off.
Admittedly in uncharted territory here as first time using the HEI charts so looking for some insight.
Does anyone have vacuum pump sizing experience using the HEI charts?
Are there better air leakage estimate guidelines for early capacity sizing?
Thanks,
JoeChem
Working on a prelimiary design for a new processing facility - reactor followed by 3 distillation columns. Need to develop a sized equipment list for approximate total installed costs.
The columns are to be operated under vacuum conditions and working on sizing vacuum pumps for the application. The systems are totally condensed and vapor pressures in the reflux drum are low so at this point looking for an air leakage estimate to get a decent idea of required pump capacity.
Have little else to go on at this point so attempting to use the air leakage curves published by the Heat Exchange Institute as a starting point but the resulting leakage numbers seem very low. For one situation we have a column with an estimated internal volume of ~ 350 ft3 to be operated at 50 mmHg. Based on the system volume and operating pressure the HEI curves predicts the leakage rate at ~ 7 lb/hr or about 31 ACFM. Comparing to vacuum pump specs on P&ID's from other processes thinking this capacity should be an order of magnitude higher. Realize safety factors should be applied but the ACFM result just seems way off.
Admittedly in uncharted territory here as first time using the HEI charts so looking for some insight.
Does anyone have vacuum pump sizing experience using the HEI charts?
Are there better air leakage estimate guidelines for early capacity sizing?
Thanks,
JoeChem
