Materials Damage Mechanisms
There are a number of mechanisms that can cause damage to materials in a
hydrogen plant. Some of these have been alluded to in the above discussion. For
a complete review of the damage mechanisms and management practices, please
refer to API RP-571. This is an excellent resource for any type of system.
For general reference, the mechanisms highlighted in RP-571 for hydrogen
plants are summarized in Table 3.
Operations and Monitoring
Operations
The following discussion will briefly describe the main operating phases of an SMR
hydrogen plant from start-up through shutdown. Initial commissioning of a hydrogen plant is beyond the scope of this discussion. For additional detail, consult the
references listed at the end of this chapter.
• Start-up
Start-up of a hydrogen plant follows this general outline:
– Inventory water in the steam system. If the unit has solvent CO 2 purification,
the solvents are inventoried in parallel.
– Air-free the process system with nitrogen.
– Pressure and circulate the process system with a noncondensable gas.
This is often nitrogen, but pure hydrogen or natural gas can also be used. Do
not use reformer hydrogen.
It is also possible to heat the furnace to 800 F in the flue without circulation.
The downside of this approach is that the high-temperature shift converter
is not heated up, so it must be bypassed when steam is introduced and then
heated later with process flow.
If the system uses a LTS converter, this converter should be bypassed. It will
be activated later.
– Fire the reforming furnace and heat to about 800
F in the furnace outlet flue
gas (convection inlet) at 50–100
F per hour.
When the flue gas reaches the required conditions, the SCR (if applicable) can
be started.
Initially, you would use only a few burners evenly distributed in the furnace.
As the furnace heats up, add more burners and ensure they are evenly
distributed in the firebox to avoid tube failures from flame impingement.
These comments apply throughout the start-up procedure.
– Slowly start process steam and increase steam rate to at least 50 % of design
with continued heating to 1,000
F in the process outlet temperature from the
furnace.
Inert circulation can be discontinued at this point since the main flow is now
steam.
Hydrogen Production and Management for Petroleum Processing
601
There are a number of mechanisms that can cause damage to materials in a
hydrogen plant. Some of these have been alluded to in the above discussion. For
a complete review of the damage mechanisms and management practices, please
refer to API RP-571. This is an excellent resource for any type of system.
For general reference, the mechanisms highlighted in RP-571 for hydrogen
plants are summarized in Table 3.
Operations and Monitoring
Operations
The following discussion will briefly describe the main operating phases of an SMR
hydrogen plant from start-up through shutdown. Initial commissioning of a hydrogen plant is beyond the scope of this discussion. For additional detail, consult the
references listed at the end of this chapter.
• Start-up
Start-up of a hydrogen plant follows this general outline:
– Inventory water in the steam system. If the unit has solvent CO 2 purification,
the solvents are inventoried in parallel.
– Air-free the process system with nitrogen.
– Pressure and circulate the process system with a noncondensable gas.
This is often nitrogen, but pure hydrogen or natural gas can also be used. Do
not use reformer hydrogen.
It is also possible to heat the furnace to 800 F in the flue without circulation.
The downside of this approach is that the high-temperature shift converter
is not heated up, so it must be bypassed when steam is introduced and then
heated later with process flow.
If the system uses a LTS converter, this converter should be bypassed. It will
be activated later.
– Fire the reforming furnace and heat to about 800
F in the furnace outlet flue
gas (convection inlet) at 50–100
F per hour.
When the flue gas reaches the required conditions, the SCR (if applicable) can
be started.
Initially, you would use only a few burners evenly distributed in the furnace.
As the furnace heats up, add more burners and ensure they are evenly
distributed in the firebox to avoid tube failures from flame impingement.
These comments apply throughout the start-up procedure.
– Slowly start process steam and increase steam rate to at least 50 % of design
with continued heating to 1,000
F in the process outlet temperature from the
furnace.
Inert circulation can be discontinued at this point since the main flow is now
steam.
Hydrogen Production and Management for Petroleum Processing
601