today are generally special low-NOx styles. In PSA hydrogen plants, the burners
have an extra, low-pressure-drop nozzle for PSA off-gas.
Arrangement or design of the burners must avoid flame impingement on the
tubes. All burners may not be the same size, as dictated by the heat input
requirements in a given section of the heater.
• Convection section – The convection sections of hydrogen plant furnaces generally have a series of services. Typically, you will see coils for:
– Steam superheat
– Mixed steam/feed preheat
– Steam generation (one or more levels)
– BFW economizer/preheat
– Combustion air preheat
Inlet from Pigtail
Inlet from
Pigtail
Cat
Bed
Cat
Bed
Outlet to
Pigtail
Bottom Flange for Dumping
Outlet to Header
(May Have Short Pigtail)
Tubes are 35-55 ft Long
Packed with Catalyst
Tubes may be top
or bottom
supported.
Catalyst
Support
Cone or
Grid
Fig. 14 Some typical SMR tube arrangements. Note: These are examples only. There are many
styles in use
596
S.A. Treese