Vapor
Holders
·
Double the Size of Your Current Vapor Recovery/Combustion
System
·
Greatly Reduce or Eliminate Assist Gas
·
Reduce System Emission Rates By Stabilizing Loading
Volumes
·
Reduce System Operating and Maintenance Costs
R.
A. Nichols Engineering Vapor Holders store excess vapor, which is later
processed by a vapor recovery or combustion system. The Vapor Holder is sized to
ensure that the terminal equipment can operate for a minimum 5-minute cycle and
still be large enough to handle any rack surge. A blower package is used with
the Vapor Holder and is sized to send vapor to the process system at a constant
flow rate, typically 60% of capacity. In many cases, a Vapor Holder can double a
system thru-put by eliminating high flow rates during peak loading, which can
overload a system. Vapor Holders, used in conjunction with a R. A. Nichols
Equalizer, have been used extensively with terminal combustion systems. They
stabilize the vapor concentration and flow, removing the need for assist gas to
maintain burner efficiency. In addition, Vapor Holders used with Carbon Units
provide constant loading and remove concentration and volume spikes, which can
fail the unit. Furthermore, the unit is only activated when it is necessary to
process vapor, this reduces the operating time of the unit and assist gas cost.
Many vapor holders are oversized for the terminal in which they are installed,
to allow maintenance time for the system equipment, without having to disrupt
loading.
The
R. A. Nichols Engineering Vapor Holder is a cylindrical, self-supporting roof,
steel tank with a vapor bladder. The R. A. Nichols Vapor Holder has free
floating ring, a top bladder fabric across the ring, and a truncated conical
fabric which is attached at the large diameter to the tank and at the small
diameter to the ring. The ring and bladder effectively form a piston that floats
within the cylindrical tank. As vapor causes the ring to rise from the floor to
the tank roof, the bladder measurable vapor storage volume equals a high
percentage of the total tank volume.
Vapor can be stored in a Vapor Holder until
processed. We typically start our process units when the system has reached the
intermediate fill level. A vapor blower is used to pull vapor from the tank to
be processed.
R. A.
Nichols Ring bladders are designed to not experience unstable behavior or rub
against the walls and/or roof in either operating or full bladder modes. The
proprietary R. A. Nichols Ring design provides a stable, roughly linear vapor
volume versus ring position. The R. A. Nichols Vapor Bladder uses approximately
85% of the tanks total volume. Ring bladders have over twice the measurable
volume of hemispherical and non-ring designs. Over 120 R. A. Nichols Vapor
Holders have been built with measurable volumes from 3,000 cf to 222,000 cf.
Tank sizes range from 10' dia. x 20' high to 70' dia. x 64' high and are in
service in the United States, Mexico, Europe, Asia, and Australia; some bladders
have been in continuous service for more than 20 years.
The
effectiveness of vapor holders has led four major oil distributors to retrofit
R. A. Nichols Vapor Holders to their condensation and charcoal systems. Vapor
holders have been so effective that charcoal manufactures have designed special
charcoal systems for use with R. A. Nichols Vapor Bladders. The vapor holder
cuts operating time for on-line refrigeration and carbon systems and therefore
cuts operating and maintenance costs.
The
R. A. Nichols Engineering Vapor Holder has little to no maintenance costs when
installed properly. The vapor bladder has an average seal life of approximately
7 years and an approximate bladder life of over 10 years. We have units
installed in the field that have been in operation even longer without failure.
The tank gauging and vents must be checked to ensure proper operation and the
blower package must be maintained to ensure long life.
R. A. Nichols Engineering Vapor Recovery Systems
have been designed to utilize our Vapor Holders. By using a Vapor Holder we can
minimize our initial costs, as well as our maintenance and operating cost. Vapor
Holders provide flexibility that cannot be achieved otherwise. Systems can be
engineered to handle pipeline deliveries while truck loading is occurring,
usually without increasing the size of your current unit. Vapor Holders have
been used with cone roof tankage to provide vapor balance and greatly reduce the
use of the process system. Maintenance can be done, on process equipment until
the Vapor Holder is full, without taking down the rack. R. A. Nichols
Engineering Vapor Recovery Systems can be designed to process the vapor from the
Vapor Holder with our Vapor Recovery Unit and Burner or directly with a Burner.
