Additional discussion of PSAs follows later in this chapter.
Other Options
Over the Fence
A refiner does not necessarily have to operate his own hydrogen plant, or even
hydrogen recovery units. Several industrial gas supply companies will build and
operate facilities to make or recover hydrogen for a refinery. This service can be
provided onsite or offsite. Here, this arrangement is referred to as “over-the-fence”
supply. The supplier will charge for the hydrogen. The charge includes cost of
operation, cost of the facilities he needs to build (amortized over time), and a profit
margin. There is usually a take-or-pay arrangement for a minimum volume of
hydrogen. Handling of emissions impacts can be negotiated.
This type of arrangement is especially advantageous where several facilities in
an area need hydrogen. An industrial gas supplier can build a pipeline connecting
the facilities, along with one or more hydrogen production or recovery units to
supply the pipeline. The supplier may take refinery off-gases to make the hydrogen
and return steam as well as hydrogen. The potential for multiple sources of
hydrogen producing into the pipeline improves the reliability of hydrogen supply.
Involvement over the fence can also be as simple as the gas supplier installing a
membrane unit inside the refinery to recover hydrogen from off-gas from a catalytic
reformer, for instance. The supplier operates and maintains the membrane unit for
a fee.
Industrial gas companies often are better (i.e., more reliable) at operating
hydrogen plants and recovery facilities than a refiner, since this is their main
business. The resulting reliable hydrogen supply means fewer production problems
in the refinery.
This type of service is well established by companies like Air Products, Air
Liquide, Praxair, and others.
~300 psig
Low Purity
Feed Gas
Feed Gas
Compressor
(If Required)
Offgas
Compressor
(If Required)
Offgas to
Fuel Gas
~50-75 psig
Liquids
~290 psig, 99%+ H2
Recovered
Hydrogen
Offgas/Tailgas
~3-10psig, Low purity
Liq
KOP
PSA
Unit
(70-90%
Recovery)
Fig. 21 An example of a hydrogen recovery PSA application
Hydrogen Production and Management for Petroleum Processing
625
Other Options
Over the Fence
A refiner does not necessarily have to operate his own hydrogen plant, or even
hydrogen recovery units. Several industrial gas supply companies will build and
operate facilities to make or recover hydrogen for a refinery. This service can be
provided onsite or offsite. Here, this arrangement is referred to as “over-the-fence”
supply. The supplier will charge for the hydrogen. The charge includes cost of
operation, cost of the facilities he needs to build (amortized over time), and a profit
margin. There is usually a take-or-pay arrangement for a minimum volume of
hydrogen. Handling of emissions impacts can be negotiated.
This type of arrangement is especially advantageous where several facilities in
an area need hydrogen. An industrial gas supplier can build a pipeline connecting
the facilities, along with one or more hydrogen production or recovery units to
supply the pipeline. The supplier may take refinery off-gases to make the hydrogen
and return steam as well as hydrogen. The potential for multiple sources of
hydrogen producing into the pipeline improves the reliability of hydrogen supply.
Involvement over the fence can also be as simple as the gas supplier installing a
membrane unit inside the refinery to recover hydrogen from off-gas from a catalytic
reformer, for instance. The supplier operates and maintains the membrane unit for
a fee.
Industrial gas companies often are better (i.e., more reliable) at operating
hydrogen plants and recovery facilities than a refiner, since this is their main
business. The resulting reliable hydrogen supply means fewer production problems
in the refinery.
This type of service is well established by companies like Air Products, Air
Liquide, Praxair, and others.
~300 psig
Low Purity
Feed Gas
Feed Gas
Compressor
(If Required)
Offgas
Compressor
(If Required)
Offgas to
Fuel Gas
~50-75 psig
Liquids
~290 psig, 99%+ H2
Recovered
Hydrogen
Offgas/Tailgas
~3-10psig, Low purity
Liq
KOP
PSA
Unit
(70-90%
Recovery)
Fig. 21 An example of a hydrogen recovery PSA application
Hydrogen Production and Management for Petroleum Processing
625