Hydrogen plant steam systems are highly stressed and require higher treatment
levels than normal boilers. In the WHB on the furnace outlet, for instance, the tube
walls will be over 1,000
F. When working with a boiler chemical vendor, you need
to be sure the vendor is experienced in hydrogen plant chemical treatment. One
specific caution is that BFW for a hydrogen plant should not use sulfite as an oxygen
scavenger. The small amount of residual sulfur that ends up in the steam will poison
the reforming catalyst.
Recycle of shift condensate can introduce higher levels of CO 2 into the steam
generated. The CO 2 becomes a corrosion problem in condensate systems using the
steam. Critical factors in preventing this corrosion are:
• Proper stripping of the shift condensate, as noted in the discussion of the watergas shift section above
• Injection of amine corrosion inhibitors into the export steam that will drop out
into the condensate headers at the correct pressures/temperatures
Unique Equipment Design and Metallurgy Considerations
In this section, we will review a few of the unique considerations in hydrogen plant
equipment design. Properly addressing these factors is critical to building and
operating a hydrogen plant.
SMR Furnace
Here, we will highlight only some of the more important considerations around an
SMR furnace. These furnaces are not “run-of-the-mill” units. They require design
experience. For very large furnaces, computational fluid dynamics (CFD) may be
employed to ensure heat release and flow in the firebox are properly designed.
• Style of furnace – The SMR furnaces are generally some of the largest, if not the
largest, fired heaters in a refinery. Several furnace types have been used, as
shown in Table 2. The table enumerates some of the key advantages and
disadvantages of each style of heater. Today, most hydrogen plants are either
down fired or terrace-wall fired.
• Radiant tubes – Some typical hydrogen plant tube configurations are depicted in
Fig. 14.
The tubes are made of high nickel alloys (HK-40, Manurite, etc.). Tube IDs
range from 1.5 to 5.5 in.. The tube design temperature is chosen based on the
calculated maximum expected end-of-run wall temperature. The design margin
today is about 50
F higher than the maximum expected wall temperature. This
can be very tight. Our ability to monitor tube temperatures is about +/À 100
F.
Monitoring will be discussed later.
• Burners – SMR furnaces use large numbers of burners to distribute heat evenly
to all the tubes. Because the firebox operates over 2,000
F, the burners used
Hydrogen Production and Management for Petroleum Processing
595
levels than normal boilers. In the WHB on the furnace outlet, for instance, the tube
walls will be over 1,000
F. When working with a boiler chemical vendor, you need
to be sure the vendor is experienced in hydrogen plant chemical treatment. One
specific caution is that BFW for a hydrogen plant should not use sulfite as an oxygen
scavenger. The small amount of residual sulfur that ends up in the steam will poison
the reforming catalyst.
Recycle of shift condensate can introduce higher levels of CO 2 into the steam
generated. The CO 2 becomes a corrosion problem in condensate systems using the
steam. Critical factors in preventing this corrosion are:
• Proper stripping of the shift condensate, as noted in the discussion of the watergas shift section above
• Injection of amine corrosion inhibitors into the export steam that will drop out
into the condensate headers at the correct pressures/temperatures
Unique Equipment Design and Metallurgy Considerations
In this section, we will review a few of the unique considerations in hydrogen plant
equipment design. Properly addressing these factors is critical to building and
operating a hydrogen plant.
SMR Furnace
Here, we will highlight only some of the more important considerations around an
SMR furnace. These furnaces are not “run-of-the-mill” units. They require design
experience. For very large furnaces, computational fluid dynamics (CFD) may be
employed to ensure heat release and flow in the firebox are properly designed.
• Style of furnace – The SMR furnaces are generally some of the largest, if not the
largest, fired heaters in a refinery. Several furnace types have been used, as
shown in Table 2. The table enumerates some of the key advantages and
disadvantages of each style of heater. Today, most hydrogen plants are either
down fired or terrace-wall fired.
• Radiant tubes – Some typical hydrogen plant tube configurations are depicted in
Fig. 14.
The tubes are made of high nickel alloys (HK-40, Manurite, etc.). Tube IDs
range from 1.5 to 5.5 in.. The tube design temperature is chosen based on the
calculated maximum expected end-of-run wall temperature. The design margin
today is about 50
F higher than the maximum expected wall temperature. This
can be very tight. Our ability to monitor tube temperatures is about +/À 100
F.
Monitoring will be discussed later.
• Burners – SMR furnaces use large numbers of burners to distribute heat evenly
to all the tubes. Because the firebox operates over 2,000
F, the burners used
Hydrogen Production and Management for Petroleum Processing
595