I've been asked to review some VRU designs for a tank terminal containing HC (activated carbon beds with PSA followed by a scrubber), but admittedly I do not have hands-on experience with VRUs so would like to seek everyone's experience. Design is for 1000 NCMH.
Couple initial questions:
1. Tank products are mainly gasoline but do include heavier HC. Most VRU designs call for adsorption with activated carbon bed, followed by desorption/regeneration at 25-50 mmHg for 10-15 minutes cycles. Are these vacuum pressure and duration settings enough for full regeneration? I'm a bit incredulous because the heavier HC will be harder to desorb, and I worry that they will accumulate over time to kill the effectiveness of the VRU.
2. From what I understand, adsorption of lighter HC (e.g. ethanes) by activated carbon is poor. Does the adsorption truly improve with specialty activated carbon pellets (I saw a quote for a specialty 4mm cylindrical activated carbon product that was multiples of the price of a "generic" brand)?
2. Vacuum pump - From what I've read, it seems that the top reason for VRU failure is the vacuum pump. Do people have a favorite type (or brand/model?) for this application? I understand that oil seal vacuum pump seems to be most popular, but I would prefer to rely on advice from folks with real VRU experiences.
Thank you!
Couple initial questions:
1. Tank products are mainly gasoline but do include heavier HC. Most VRU designs call for adsorption with activated carbon bed, followed by desorption/regeneration at 25-50 mmHg for 10-15 minutes cycles. Are these vacuum pressure and duration settings enough for full regeneration? I'm a bit incredulous because the heavier HC will be harder to desorb, and I worry that they will accumulate over time to kill the effectiveness of the VRU.
2. From what I understand, adsorption of lighter HC (e.g. ethanes) by activated carbon is poor. Does the adsorption truly improve with specialty activated carbon pellets (I saw a quote for a specialty 4mm cylindrical activated carbon product that was multiples of the price of a "generic" brand)?
2. Vacuum pump - From what I've read, it seems that the top reason for VRU failure is the vacuum pump. Do people have a favorite type (or brand/model?) for this application? I understand that oil seal vacuum pump seems to be most popular, but I would prefer to rely on advice from folks with real VRU experiences.
Thank you!
